IT201800006586A1 - SENSOR DEVICE FOR LIQUID SUBSTANCE CONTAINERS - Google Patents

Description

DESCRIPTION of the industrial invention entitled:

"Sensor device for containers of liquid substances",

TEXT OF THE DESCRIPTION

Field of the invention

The present invention relates to sensor devices used in combination with generic containers intended to contain a liquid substance and has been developed with particular reference to sensor devices which include an optical arrangement for detecting at least one characteristic quantity of the liquid substance.

The invention finds a preferred application in the sector of vehicles or apparatuses in general which provide internal combustion or endothermic engines, particularly in combination with hydraulic systems or tanks intended to transit or contain a substance, such as a fuel or a liquid solution. necessary for the operation of an exhaust gas treatment system of an internal combustion engine, where the aforementioned optical arrangement is used to detect at least one concentration of the substance or solution.

State of the art

For the purposes of controlling substances contained in generic containers, the use of sensors with characteristics such as level, temperature, quality, etc. is common. A typical example is represented by tanks of liquid substances, belonging to exhaust gas emission systems of some types of vehicles, designed for the purpose of reducing the release of nitrogen oxides (NOx) into the atmosphere. A particularly popular system for this purpose is based on the process known as SCR (Selective Catalytic Reduction), which allows the nitrogen oxides of gases to be reduced by injecting a liquid reducing substance into the exhaust line. These treatment systems assume that the reducing agent is dosed and injected into the exhaust gas stream to convert nitrogen oxide (NOx) into nitrogen (N2) and water (H2O). The reducing substance typically consists of a solution of water and urea.

The correct functioning of these systems presupposes that the relative control unit recognizes the presence of the reducing substance inside the tank, particularly by measuring its level and signaling the possible need for topping up. In some cases, information relating to the characteristics of the reducing substance is also provided, such as, for example, characteristics related to its composition.

For example, WO 2010/151327 describes a reservoir of a reducing substance on which a level sensor is mounted, configured to generate a radio frequency signal in a resonant circuit and to propagate the resulting electromagnetic radiation in the substance, as well as to detect changes in the impedance and resonance of the aforementioned circuit, where these changes are considered representative of changes in the conductivity and dielectric properties of the substance which are proportional to the quantity of the substance, or its level. The level sensor can be equipped with capacitive and / or resistive probes to detect the quality of the substance. A further electro-optical sensor, able to detect other characteristics of the substance, can be optionally mounted in correspondence with a lateral wall of the tank. This further optical sensor is submerged by the substance when it has a sufficient level in the tank; an emitter directs a beam of light towards a prism which forms a tip of the sensor and is configured to refract the radiation in the liquid, the reflected light being detected by a receiver. The reflected light is considered to be directly proportional to the refractive index of the substance, which allows you to determine whether the substance contained is water, or a urea solution, and the concentration of this solution.

Optical sensors of this type are generally complicated in construction and assembly, particularly in view of the need to ensure the correct positioning of the emitter and receiver.

Summary and synthesis of the invention

The object of the present invention is essentially that of solving the drawbacks highlighted above in a simple, economical and reliable way.

This and still other objects, which will become clearer hereinafter, are achieved according to the present invention by a sensor device having the characteristics indicated in the attached claims. The claims are an integral part of the technical teaching provided herein in relation to the invention.

Brief description of the drawings

Further objects, characteristics and advantages of the present invention will become clear from the following detailed description, carried out with reference to annexed schematic drawings, provided purely by way of non-limiting example, in which:

- Figure 1 is a sectional perspective view of a generic container comprises a sensor device according to possible embodiments of the invention;

- Figure 2 is a partially sectioned perspective view of a sensor device in accordance with possible embodiments of the invention;

- Figures 3-4 are perspective views from different angles of a circuit of a sensor device according to possible embodiments of the invention;

- Figures 5-6 are exploded views, from different angles, of a sensor device according to possible embodiments of the invention;

- Figures 7-9 are perspective views, from different angles, of an optical module of a sensor device in accordance with possible embodiments of the invention;

- Figure 10 represents, with different perspective views, an emitter of electromagnetic radiation and a related component, usable in a sensor device in accordance with possible embodiments of the invention;

- Figure 11 is a possible electrical diagram of an optical module of a sensor device in accordance with possible embodiments of the invention;

Figures 12-14 are perspective views of semi-finished products which can be used to make an optical module of the type illustrated in Figures 7-9;

Figures 15-16 are perspective views of a mold that can be used for making an optical module of the type illustrated in Figures 7-9;

- figure 17 is a partial perspective view of a circuit of a sensor device according to possible embodiments of the invention, with an associated optical module of the type illustrated in figures 7-9;

- Figure 18 is a perspective view aimed at showing an assembly step of a sensor device in accordance with possible embodiments of the invention;

- Figures 19 and 20 are a sectional perspective view and a perspective view of a portion of a sensor device in accordance with possible embodiments of the invention;

- Figure 21 is a vertical section of a sensor device according to possible embodiments of the invention;

- Figures 22-26 are partial vertical sections aimed at exemplifying the operation of an optical sensor of a sensor device in accordance with possible embodiments of the invention;

- Figure 27 is a simplified block diagram of an optical sensor of a sensor device according to possible embodiments of the invention;

- Figures 28-29 are exploded views, from different angles, of a sensor device in accordance with possible embodiments of the invention;

- Figures 30-33 are perspective views aimed at showing some assembly steps of a sensor device in accordance with possible embodiments of the invention;

- Figure 34 is an exploded view of a sensor device according to possible embodiments of the invention;

- Figures 35-36 are perspective views from different angles of a protection element that can be used in a sensor device in accordance with possible embodiments of the invention;

- Figures 37-38 are perspective views, from different angles, of an optical module of a sensor device in accordance with possible embodiments of the invention;

- Figures 39-43 are perspective views aimed at showing some assembly steps of a sensor device in accordance with possible embodiments of the invention; - Figures 44 and 45 are perspective views of an elastic element and a relative locking element that can be used in a sensor device according to possible embodiments of the invention;

- Figures 46-48 are partial perspective views aimed at showing some fixing steps of an elastic element of the type illustrated in Figure 44, by means of a locking element of the type illustrated in Figure 45;

- Figures 49-50 are perspective views, from different angles, of an optical module of a sensor device in accordance with possible embodiments of the invention;

- Figure 51 is a perspective view of an elastic element usable in a sensor device according to possible embodiments of the invention;

- Figure 52 is a partial perspective view aimed at showing an assembly step of a sensor device in accordance with possible embodiments of the invention;

Figures 53-57 are partial perspective views aimed at showing some fixing steps of an elastic element of the type illustrated in Figure 51;

- Figures 58-59 are perspective views from different angles of a portion of a sensor device according to possible embodiments of the invention;

- Figure 60 is a perspective view showing a part of a sensor device according to possible embodiments of the invention;

- Figure 61 is an exploded view of a sensor device according to possible embodiments of the invention;

- Figures 62-63 are perspective views, from different angles, of an optical module of a sensor device in accordance with possible embodiments of the invention;

- Figure 64 is a perspective view of a protection element usable in a sensor device according to possible embodiments of the invention;

- Figures 65-69 are perspective views aimed at showing some steps of fixing a sensor device in accordance with possible embodiments of the invention;

- Figure 70 is a sectional perspective view of a portion of a sensor device according to possible embodiments of the invention;

- Figure 71 is a vertical section of a sensor device according to possible embodiments of the invention;

- Figure 72 is a partially exploded view of a sensor device according to possible embodiments of the invention;

- Figure 73 is a partial exploded view of a sensor device according to possible embodiments of the invention;

- Figures 74-75 are perspective views, from different angles, of an optical group of a sensor device in accordance with possible embodiments of the invention;

Figure 76 is an exploded view of an optical unit of the type illustrated in Figures 75-76;

- Figure 77 is a partial section perspective view of a portion of a sensor device according to possible embodiments of the invention;

- Figure 78 is a perspective view showing a part of a sensor device according to possible embodiments of the invention;

- Figure 79 is a partial and schematic section of a portion of a sensor device according to possible embodiments of the invention;

- figure 80 is an enlarged detail of figure 79;

- Figure 81 is a partially exploded view of a part of a sensor device according to possible embodiments of the invention;

- figure 82 is an exploded view of an optical module of a sensor device according to possible embodiments of the invention;

- Figure 83 is a partially exploded view of a part of a sensor device according to possible embodiments of the invention;

- Figures 84-85 are perspective views aimed at showing some assembly steps of a sensor device in accordance with possible embodiments of the invention;

- figure 86 is a vertical section of a sensor device according to possible embodiments of the invention;

- Figures 87-88 are partial vertical sections aimed at exemplifying the operation of an optical sensor of a sensor device in accordance with possible embodiments of the invention;

- Figures 89-90 are partially exploded views, from different angles, of a sensor device according to possible embodiments of the invention;

- Figure 91 is an exploded view of an optical module of a sensor device according to possible embodiments of the invention;

- Figures 92-93 are perspective views from different angles of an optical module of a sensor device in accordance with possible embodiments of the invention;

- Figures 94-95 are perspective views aimed at showing some assembly steps of a sensor device in accordance with possible embodiments of the invention;

- Figures 96-97 are vertical sections, according to two different parallel section axes, of a sensor device in accordance with possible embodiments of the invention;

- Figure 98 is an electrical diagram of an optical module usable in a sensor device in accordance with possible embodiments of the invention;

- Figure 99 is a simplified block diagram of an optical sensor of a sensor device according to possible embodiments of the invention;

- Figures 100-101 are partially exploded views, from different angles, of a sensor device according to possible embodiments of the invention;

- figures 102-103 are perspective views, from different angles, of an optical element of a sensor device in accordance with possible embodiments of the invention;

- Figure 104 is a partially exploded perspective view of a circuit of a sensor device according to possible embodiments of the invention, with a relative optical module;

- figures 105-108 are perspective views aimed at showing some assembly steps of a sensor device in accordance with possible embodiments of the invention;

- Figure 109 is a vertical section of a sensor device according to possible embodiments of the invention;

Figure 110 is a horizontal section of the sensor device of Figure 109; Figure 111 is a vertical section of the sensor device of Figures 109-110, according to a section plane orthogonal to that of Figure 109;

- Figure 112 is a schematic perspective view of an electrical connection element, in the form of a flexible circuit support, usable for the construction of optical modules in accordance with embodiments of the invention;

- figures 113 and 114 are schematic perspective views from different angles of a support and electrical connection structure integrating an element of the type shown in figure 112;

- Figures 115 and 116 are schematic perspective views from different angles of an optical module usable in a sensor device according to possible embodiments of the invention, in two different conditions;

- Figures 117 and 118 are partially exploded schematic views of a support structure and electrical connection of an optical module that can be used in a sensor device in accordance with possible embodiments of the invention; And

Figure 119 is a schematic perspective view of an optical module including the structure of Figures 117-118.

Description of preferred embodiments of the invention

The reference to an embodiment within this description indicates that a particular configuration, structure, or feature described in relation to the embodiment is included in at least one embodiment. Thus, phrases such as "in one embodiment", "in various embodiments" and the like, possibly present in different places of this description, do not necessarily refer to the same embodiment. In addition, particular conformations, structures or characteristics defined within this description can be combined in any suitable way in one or more embodiments, even different from those depicted. The numerical and spatial references (such as "upper", "lower", "high", "low", etc.) used here are only for convenience and therefore do not define the scope of protection or the scope of the forms of implementation. For example, it should be considered that, for the sake of greater clarity, in various attached figures the device object of the invention is represented in an inverted condition with respect to that of normal operation. It should be noted that, in the present description and in the attached claims, the adjective "external" - when referring to a surface of at least part of a wall (interface) of a body of the device described here - is intended to designate a surface intended for be facing the inside of a generic container or duct, or in contact with the liquid substance subject to detection, while the adjective "internal" is intended to designate an opposite surface of this wall, or a surface intended to be outside the tank or duct, and in any case not in contact with the substance. It is also specified that in this description and in the attached claims, "optical radiation" means that part of the electromagnetic spectrum that includes radiations between 100 nanometers (nm) and 1 millimeter (mm), including ultraviolet radiation (100 - 400 nm ), visible radiation (380-780 nm) and infrared radiation (780 nm –1 mm); The scope of the invention also includes both "coherent" or laser type optical radiation sources and "non-coherent" optical radiation sources. Furthermore, where not otherwise specified or evident from the context described, the term "material", for example when referring to a body of a described element, must be understood as indicative of a single material (for example a metal or a plastic material) or of a composition of several materials (for example a metal alloy, or a composite material, or a mixture of materials, etc.).

In Figure 1, 1 indicates as a whole a generic container, such as a tank, particularly a tank of a motor vehicle. In the following of the present description it is assumed that such container 1 (hereinafter also defined as a tank) is intended to contain a liquid additive, or reducing agent, and is part of a system for the treatment of exhaust gases of a combustion engine internal, schematically indicated by block 2. In various embodiments, the treatment system 2 is of the SCR type, as explained in the introductory part of the present description, used for the abatement of nitrogen oxide emissions, for example in motor vehicles, especially with diesel engine. The aforesaid reducing agent is therefore preferably a liquid solution, particularly urea in distilled water solution, such as the one known commercially by the name AdBlue ™. The container 1 could in any case be replaced by a conduit of a hydraulic system and / or used for other purposes and / or in sectors other than the automotive one, and intended to contain a different liquid or fluid substance of another type that can be detected optically (the following definitions occasionally referring to a liquid substance or to a reducing agent can therefore be understood as referring to a different liquid or fluid substance). The main body 1a of the tank 1 can be made of any material, preferably a material which is chemically resistant to the substance or liquid solution and, preferably, electrically insulating, for example a suitable plastic material, according to the known technique, such as a high density polyethylene (PEHD or HDPE). The tank 1 can optionally be associated with a heater of a per se known type, used to heat the tank itself and / or its contents, for example in the event of freezing. An electric heater is schematized in the figure by the block indicated with EH. Advantageously, in various embodiments, such a heater EH is associated or integrated in the sensor device according to the present invention.

In the schematic example shown, the tank has an upper part 3, for example one of its upper walls, in correspondence with which an opening 3a is provided for topping up the liquid solution. A lower part 4 of the tank 1, for example its bottom wall, then has an outlet opening 5, through which the solution comes out or is sucked in, for example by means of a pump, to feed the liquid to the system 2. Still in in correspondence with the lower part 4, the tank 1 has a second opening, indicated with 6, in correspondence with which a body of a sensor device according to various possible embodiments of the invention is sealed. In fact, in preferred applications, the sensor device object of the invention is intended to be installed in the lower part of a container or a duct, so that an external surface of its body is at least partially in contact with the liquid substance, even when this has a minimum level.

In various embodiments, a body of the sensor device according to the invention itself defines at least part of the outlet opening of the tank 1, with the latter which could therefore be provided with only one opening 6, instead of the openings 5 and 6 .

The sensor device, indicated as a whole with 10, includes a housing and / or mounting part 12, configured to be hermetically coupled to the opening 6. The part 12 in any case has a closing or bottom structure including at least one wall (hereinafter indicated with 21) which is intended to be in contact with the liquid solution contained in the tank 1. As will be seen, according to the invention, the sensor device 10 comprises a detection arrangement, particularly of the optical type, for the detection of one or more more characteristics of the substance or liquid solution contained in the tank 1: for this purpose, the sensor device 10 includes a detection part (hereinafter also defined as the optical positioning site), which in various embodiments can be configured as protruding towards the inside the tank 1.

It should be noted that, instead of being mounted directly in correspondence with the opening 6 of the tank 1, the device 10 according to the invention can realize, or be associated with or integrated into, a component which is mounted hermetically in correspondence with a different opening of the tank itself, for example defined in a component of the type commonly known as UDM, or Urea Delivery Module (see for example WO 2008/138960 A). Components of this type typically include other functional devices and / or a passageway for the withdrawal of the reducing agent from the tank, to which passageway is generally connected the inlet of the pump for the suction of the agent itself from the tank. . In any case, as will be seen, in preferred embodiments the casing body of the device 10, and in particular at least its housing portion 12, is intended to extend mainly outside the container or duct in which the substance is located. liquid, with the exception of at least a portion of one of its walls to which the optical detection arrangement is associated. In other words, therefore, the casing body of the sensor device object of the invention is preferably not intended to be completely or predominantly positioned within a volume containing the liquid substance, or intended to be completely or predominantly immersed in this liquid substance. 'last.

In Figure 2 a device 10 according to an embodiment is shown in isolation. The device 10 has a device body 10a which defines the housing and assembly part 12, which is preferably provided with a closing cover 13.

Preferably, the body 10a is internally hollow to house at least part of the components of an arrangement for detecting one or more characteristics of the substance contained in the tank 1, particularly a sensor of the optical type, preferably of the opto-electronic type, suitable for detecting the quality of the aforementioned substance (in the following, for simplicity, reference will therefore also be made to a quality survey of the substance).

In various embodiments the body 10a, or at least a part of its portion intended for contact with the liquid solution, is formed with a printable thermoplastic material, such as a polypropylene (PP) or a high density polyethylene (HDPE) or a polysulfone ( PSU). Practical tests carried out by the Applicant have also made it possible to ascertain that a particularly suitable material - also in view of the particular methods of quality detection described below - is a cyclo-olefin copolymer (COC - Cyclic Olefin Copolymer).

Materials of this type - also used in the medical field - have particularly advantageous characteristics for the application considered here, among which the low density, the very low water absorption, the excellent barrier properties to water vapor, must be emphasized. the high rigidity, strength and hardness, the high resistance to extreme temperatures and thermal shocks, the excellent resistance to aggressive agents such as acids and alkalis, the excellent electrical insulation properties, the easy processing using common methods of treatment of thermoplastic materials , such as injection molding, extrusion, blow molding, injection blow molding.

Again in Figure 2 it can be seen how the housing part 12 defines a cavity, indicated as a whole with H, which together with the cover 13 defines a housing for at least part of the electrical and electronic detection components. In a preferred embodiment, at least part of such components is mounted on an electrically insulating substrate 15 which forms a circuit support or PCB (Printer Circuit Board), hereinafter also referred to as a "circuit", since they are allocated and connected to it electrical and / or electronic components. The support 15 is preferably formed with material suitable for making printed circuits, such as for example FR4 or a similar composite material such as fiberglass, or again in ceramic or polymer-based material, preferably a printable material for the purposes of making the support 15.

Referring also to Figures 3 and 4, the support 15 is mainly associated with the electronic detection and / or control components of the device 10, which is connected to the optical sensor. The aforementioned components preferably includes components for the treatment and processing of signals relating to the detection of at least one characteristic of the substance, such as its quality.

The support 15 is also preferably associated with relative terminals for the external electrical connection of the device 10, preferably having a generally flattened shape, visible for example in Figures 5 and 6, where they are indicated by 16. These terminals 16 form, with a connector body 13a, a cover 13, an interface or connector for the external electrical connection of the device 10, for example to a control unit of the vehicle's on-board system 2.

In the illustrated example, a single circuit support 15 is provided, but in possible embodiment variants several circuit supports can be provided, connected to each other by suitable electrical interconnection means and possibly mechanical interconnection means, for example a circuit support including first components electrical / electronic and a circuit support including second electrical / electronic components, with electrical conductors or connectors to connect electrically conductive tracks of the two supports to each other, or a circuit support bearing part of the components relating only to quality detection (or other characteristic quantity of the substance), connected to a circuit support bearing at least part of the components relating to the detection of a different quantity, for example a temperature.

Still referring to Figures 3 and 4, in various embodiments the circuit support 15, preferably of a generally flattened shape, has associated on one of its major faces - here conventionally defined "rear" - a control circuit arrangement, generally indicated with 17, preferably comprising an electronic controller MP, for example a microprocessor or a microcontroller.

The MP controller preferably includes at least one processing and / or control logic unit, a memory circuit and inputs and outputs, including analog / digital inputs. The arrangement 17 or the controller MP then comprises elements for conditioning and / or processing the signals relating to the quality detection of the liquid solution. It should be noted that the components associated with the support 15 or the arrangement 17, with the exception of its connecting elements 16 and 53, have been shown only in figures 3-4, for the sake of clarity of the subsequent drawings. The components of the circuit arrangement 17 are connected to electrically conductive tracks provided in the support 15, not indicated.

In various embodiments, the device according to the invention comprises at least one temperature sensor, for detecting at least one between a temperature of the liquid solution and an ambient temperature, such as for example the temperature of the air inside the cavity H Preferably, at least one temperature sensor is provided on the circuit support 15. A temperature sensor, for example of the NTC type, can be mounted on the support 15 so as to be substantially in contact with the inner side of an interface wall. with the liquid substance (such as the wall hereinafter indicated with 21), as schematised by the temperature sensor 19a of figure 4. In the example shown a second temperature sensor 19b is also schematised. Assuming a mounting of the device 10 in the tank 1 of the type illustrated in Figure 1, the temperature sensor 19a can be used for measuring the temperature of the liquid, while the sensor 19b can be used to detect the temperature that exists in the cavity H, for example in order to compensate for variations or thermal drifts of the opto-electronic components and / or of the electronic components of the control circuit, in particular in order to improve the measurement of the device.

In various embodiments, such as the one exemplified here, the measurement carried out by the at least one temperature sensor provided in the device is an indirect measurement, since this temperature sensor is not directly in contact with the liquid substance. It will in fact be appreciated that, in various embodiments, the at least one temperature sensor 19a is housed inside the body 10a of the device (and specifically inside its portion 12), and therefore not directly in contact with the substance. liquid present in the tank 1, detecting at least one temperature outside the body 10a. For this purpose, in various embodiments, the control circuit arrangement 17 of the device 10 is arranged - in a per se known manner - to perform a suitable compensation of the measurement carried out by the temperature sensor 19a, which takes into account at least the presence of an interposed wall (here the wall indicated hereinafter with 21) between the temperature sensor and the substance (for example, relative corrective parameters, based on experimental analyzes, can be contained in a memory of the circuit arrangement 17).

In various embodiments, such as the one exemplified here, the measurement carried out by the at least one temperature sensor provided in the device is a direct measurement, since this temperature sensor directly detects the ambient or air temperature in contact with other components of the device, for example in the case of the temperature sensor 19b which detects the ambient temperature inside the enclosure of the device 10 in which it is located, such as the enclosure defined here by the parts 10a and 13. It will in fact be appreciated that, in various forms of actuation, at least one temperature sensor can be housed inside the enclosure of the device and intended to detect at least one temperature inside the enclosure itself.

In various embodiments, a measurement is provided carried out by two temperature sensors both located inside the device casing, preferably a direct measurement and an indirect measurement of the temperature, respectively for a measurement of the temperature inside and outside. of the casing itself.

In various embodiments at least one temperature sensor, for example one or more of those mentioned above, is provided in the device 10 to compensate for the value of the measurements carried out by means of the quality sensor.

In various embodiments, such as the one exemplified, all the sensors, in particular the quality and temperature sensors, are isolated with respect to the liquid substance, preferably through at least one wall of the body of the device.

As can be seen in Figures 5 and 6, in various embodiments the housing and / or mounting part 12 includes a peripheral wall 20 and a structure or bottom wall 21, which define the cavity H suitable for housing at least part of the components electrical and / or electronic devices of the device 10. Preferably, the peripheral wall 20 - here substantially cylindrical in shape - has a flange 20a defining a relative seat 20b, particularly a circumferential seat, for fixing in position and / or sealing the cover 13 . In the assembled condition of the device 10, at least a part of the structure or bottom wall 21 - and particularly of its external side - is intended to be in contact with the liquid solution contained in the tank: for this reason, the wall 21 will also be defined interface wall. As can be seen in particular in Figure 5, in various preferred embodiments, at their internal side, at least one of the wall 20 and the wall 21 defines / defines formations or seats for positioning the support 15 inside the cavity H, preferably but not necessarily a substantially vertical positioning; preferably, at least two formations or seats 22 in substantially opposite positions are provided in the cavity H for this purpose.

From Figures 5-6 it can be understood how, in preferential embodiments, the cover 13 also fulfills electrical connection functions, since it includes or defines a generally hollow connector casing 13a, to house the electrical terminals 16 and, possibly, at least part of the circuit 15 and / or of the optical sensor. In the example, the connector housing 13a protrudes in an axial direction of the cover 13 or of the sensor device 10 (in Figures 1 and 2, the main axis of the device is indicated with X), but other orientations are of course possible, for example orthogonal or angled to that axis. The cover 13 is intended for fixing on the main body 10a, particularly on its housing and assembly part 12, so as to close - preferably airtight - the cavity H.

In various embodiments, the cover 13 defines for this purpose a flange 13b, for fixing to the flange 20a of the part 12, for example by gluing or welding (particularly of the laser or vibration or remelting type of at least part of the perimeter of the flanges 13b and 20a in plastic material), or by other mechanical fixing between these flanges, such as a thread or a bayonet coupling, possibly with the interposition of sealing means, such as an elastic gasket. In the example of figures 5 and 6, the flange 13b of the cover 13 defines an annular projection 13b1, intended for coupling in the seat 20b of the flange 20a of the body 10a (see also figure 21 for reference), preferably, in at least one of the bodies 10a and 13 include means for fixing the device 10 to the tank, such as perimeter holes, for example holes 13d in one or more radial formations 13c of the flange 13b (see for example Figure 5).

In the assembled condition of the device 10, the terminals 16 are intended to protrude inside the connector housing 13a of the cover 13. For this purpose, the cover 13 has relative passages for these terminals, indicated with 13e in figure 6; alternatively, the terminals 16 could be overmolded by the plastic material of the cover 13. From the same figure 6 it can be seen how, in various embodiments, inside the cover 13, which also defines a relative cavity, formations or seats of positioning 13f for the support 15, preferably in positions homologous to the formations or seats 22 of the body 10a.

In accordance with the invention, as mentioned, the sensor device 10 includes at least one optical arrangement for detecting the quality (or other characteristic / characteristics) of the substance subject to control and possibly an arrangement for detecting a temperature, where preferably such arrangements of detection comprise common parts of the device 10. These common parts can be of an essentially mechanical type, such as for example a single body, such as the one indicated with 10a, or several bodies coupled together, for example welded or glued or hooked together, or even several bodies grafted at least partially into each other. In addition and / or alternatively, the common parts can be of the electrical and / or electronic type, and include for example a circuit support (such as that indicated with 15), a connection connector (such as the connector 13a, 16), one or more control circuit components (such as the MP controller).

In embodiments in which both the quality sensor and at least one sensor of another size, such as the temperature sensor, are provided, the device according to the invention, and in particular its control electronics, is designed to transmit both first information representative of the quality of the substance and second information representative of the at least one other quantity, such as a temperature value, through an electrical connector and / or through electrical terminals in common with the two (or three) detection arrangements. In various embodiments, both the first information and the second information are transmitted through the same signal, preferably the same serial signal containing a plurality of data or values, such as data or values in digital format or encoded according to a predefined protocol. For this purpose, the control electronics of the device is preferably arranged for the transmission of data, preferably in the aforementioned serial format, most preferably by means of an interface and / or a serial protocol, such as for example a SENT (Single Edge Nibble Transmission) or CAN (Controller Area Network).

In preferred embodiments of the invention, the quality detection arrangement comprises at least one optical radiation emitter and at least one optical radiation receiver, and a part of the sensor device 10, i.e. of its body 10a, is configured so as to contribute to the propagation of optical radiation from the emitter to the receiver. In the following, for the sake of simplicity, assume that the aforementioned optical radiation is in the frequencies of the visible, however it may be a different frequency of optical radiation for the purposes of the implementation of the invention: in the following, therefore, reference will be made to rays or beams of light visible. For the sake of simplicity, in the following, the quality sensor or other / other characteristic / characteristics will also be referred to as an optical sensor.

For this purpose, in various embodiments, the wall 21 which delimits the cavity H of the housing part 12 below is formed at least in part with a material suitable for the propagation of light, at least by refraction and / or reflection, and in correspondence with this part is operatively associated with the emitter and the receiver.

This material is preferably a transparent material, for example selected from cyclo-olefin copolymers (COC) or a polysulfone (PSU) or a polypropylene (PP) or a high density polyethylene (HDPE).

In various embodiments, at least a part of the wall 21 is shaped to define an optical site for positioning the aforementioned emitter and receiver.

In various preferred embodiments, said emitter and receiver are part of the same optical module, which is mounted in correspondence with the aforementioned optical positioning site. With reference to figure 5, a said site is indicated as a whole with 30, while a aforementioned module is indicated as a whole with 40 in figure 2. As will be apparent later, in various embodiments, the optical positioning site comprises a particular conformation of the wall 21, or of a part of it dedicated to the propagation of the light beam. In preferred embodiments, the optical site 30 realizes the previously mentioned second detection part of the device 10, belonging to the optical sensor, which in various embodiments is intended to protrude at least partially towards the inside of the tank 1.

Figures 7-9 show an optical module made in accordance with possible embodiments of the invention. The module 40 has a support and electrical connection structure 41 (see also Figures 5 and 6), made partly with electrically insulating material and partly with electrically conductive material. The structure 41 of the module is designed for mounting a light emitter 42 (only partially visible in figure 8, as it is covered by a relative spatial filter 43, described below, but visible in figures 5-6) and at least one receiver of light 44. In preferred embodiments of the invention, the emitter is a light source with a non-diffused Lambertian emission, for example a suitable emitter LED diode. In accordance with preferred embodiments of the invention, the light receiver 44 comprises two distinct receivers, indicated with 44a and 44b, for example photo-detectors or photo-diodes suitable for detecting the light emission generated by the emitter 42.

In various embodiments, the emitter 42 and the receiver 44 have their respective active emitting and receiving parts, respectively, which are generally turned towards each other, but arranged at an angle to each other, preferably in such a way that the respective axes intersect. Referring for example to Figure 22, the emitter 42 and the receiver 44 are arranged according to their respective planes 42x, 44x which form an angle α between them which is less than 90 °; on the other hand, the two planes passing through the axes 42y, 44y of the receiver and the emitter, respectively, (meaning by this two planes orthogonal to the axis of the sheet of figure 22), form an angle greater than 90 ° between them; in general, therefore, the axes 42y, 44y of the receiver and the emitter are inclined with respect to the main axis X of the device 10 (see figures 1 and 2).

The angle α is predefined according to the plastic material used for the interface wall (i.e. a wall of the body 10a, here the wall 21, particularly in substantial correspondence with the positioning site 30), the type of optical radiation (i.e. the type of emitter 42) to be adopted and the type of fluid to be measured.

Preferably, with the use of certain plastic materials, the angle α and / or the angle of incidence of the beam emitted by the emitter with respect to the interface surface, or the critical angle, is between 50 ° and 70 °. For example, for measuring the quality of urea in aqueous solution using COC as a plastic material, considering a light emission with a wavelength equal to or close to 630 nm, the angle α must preferably be between 52 ° and 54 °, in particular equal to 53 °. Alternatively, in the same application and using the PSU as a plastic material for the interface wall, the angle α must preferably be between 63 ° and 65 °, in particular equal to 64 °. However, in a similar configuration a suitable angle α can be predefined for other materials of the interface wall, such as for example a PP or an HDPE. Alternatively, an infrared light source or emission can be provided, for example with a wavelength equal to or close to 850 nm or 860 nm, providing an appropriate angle α, also taking into account the material of the interface wall, such as for example a COC plastic material or a PSU or a PP or HDPE. The emitter and the receiver (or its individual photo-detectors) must be positioned with their axes 42y and 44y orthogonal to the optical surfaces, so that the ray R1 affects the surface 211 at an angle (with respect to the vertical or with respect to an axis parallel to the X axis or to an axis perpendicular to the surface 211), equal to the critical angle: referring to the previous examples, with COC-urea solution this angle will preferably be between 62 ° and 66 °, in particular equal to 64 ° and with PSU-urea solution this angle will preferably be between 56 ° and 60 °, in particular equal to 58 °.

In various other embodiments, however, the emitter and receiver can be arranged in another way, for example with the respective axes 42y, 44y generally parallel (as for example in the embodiments of Figures 81-88, 89-99, 100- 111).

In preferred embodiments, the structure 41 includes a plurality of bodies formed of insulating material, which are connected to each other by means of electrically conductive elements at least partially elastically deformable. Preferably, the structure 41 includes electrical connection terminals, also at least in part elastically deformable.

In the case exemplified in Figures 7-9, the structure 41 comprises a main body 45, in a central position, essentially performing centering and fixing functions, and two lateral support bodies 46 and 47, these bodies being preferably formed of plastic or thermoplastic material, or with a printable resin.

As can be seen particularly in Figure 7, mechanical and electrical connection elements 48 and 49 protrude at two opposite peripheral sides of the central body 45, preferably constituted by elastically flexible or deformable metal conductors, to which the supporting bodies 46 and 47 are associated , respectively. At another peripheral side of the body 45, on the other hand, electrical connection terminals 50 protrude, also preferably consisting of elastically flexible metal conductors. The terminals 50 are used for the electrical connection of the module 40 to the control electronics of the device, particularly to the circuit support 15, while the conductors 48 and 49 are used for the electrical connection of the emitter 42 and of the receiver 44, i.e. detectors 44a and 44b. As will be seen, the conductors 48, 49 and the terminals 50 are arranged in such a way as to make the relative mechanical and / or electrical connection elastic or deformable, in order to guarantee the precise relative positioning between parts of the device, as well as compensate for any dimensional tolerances and / or positioning to avoid damage caused by assembly and / or vibration during operation.

In various embodiments, a first centering and / or locking formation 51 is defined in correspondence with the upper face of the central body 45, preferably having a substantially cylindrical shape and affected by a transversal cut, not indicated. As will be seen, this upper formation 51 is configured to contribute to a centering and / or locking of a locking and / or positioning element, indicated with 60 in Figures 5 and 6, hereinafter described. Preferably, the formation 51 is also internally hollow, in order to contribute to a centering of the module 40 with respect to the relative positioning site 30. In preferred embodiments, the body 45 is crossed by two through openings 51a, which open substantially in correspondence with of two diametrically opposite parts of the formation 51, particularly respectively at the ends of the aforementioned transverse cut.

In various embodiments, a second formation 52 is defined in correspondence with the lower face of the central body 45, also intended to perform centering or positioning functions of the module 40 relative to the site 30, in order to ensure the correct positioning of the emitter 42 and of the receiver 44 with respect to optical surfaces obtained at the site 30. To this purpose, as will be seen, the elasticity or at least partial elastic deformability of the conductors 48 and 49 contributes. In preferred embodiments, the formation 52 or part of the body 45 also performs optical screen functions, as described below.

The formation 52 includes at least one projecting wall 52a, which extends in a generally orthogonal direction with respect to at least part of the conductors 48 and 49, such as a part overmoulded by the body 45.

Preferably, at the two longitudinal ends of the wall 52a two further projecting walls 52b are provided, transversal to the wall 52a: in these embodiments, therefore, the formation 52 substantially has an H-shaped plan profile, including a projecting wall; at the ends of the walls 52b further small reinforcing walls or ribs can optionally be provided, as illustrated.

As can be seen, particularly from Figures 8 and 9, the two through openings 51a open, at the lower face of the body 45, on the two sides of the wall 52a.

The two lateral bodies 46 and 47 each have, on their relative upper face, a groove 46a, 47a, designed to form the seat for two opposite arms of the aforementioned locking and / or positioning element 60, which is preferably an elastic element. The shape of the grooves or seats 46a, 47a is such as to avoid movement of the aforementioned arms and ensure adequate pressure of the module 40 and / or of the two lateral bodies 46 and 47 against relative abutment means, such as a formation forming part of the site 30 or belonging to to wall 21.

Preferably, at least one positioning and / or anti-rotation element is associated with the module 40 or at least one of the bodies 46 and 47: for this purpose, in various embodiments the bodies 46 and 47 each have at least one lower appendage or protrusion 46b and 47b, for example in the form of a tooth, in correspondence with their lower peripheral edge, intended to couple with a suitable positioning seat of the site 30 or of the wall 21; alternatively the aforesaid said positioning and / or anti-rotation elements could be in the form of seats, intended to couple with a suitable projection or positioning tooth of the site 30 or of the wall 21.

The ends of the respective conductors 48 and 49 are provided at the lower face of the bodies 46 and 47, for connecting the emitter 42 and the two photo-detectors 44a and 44b which make up the receiver 44. The electrical connection of these electronic components to conductors 48 and 49 can be carried out by means of standard technique in the field of electronic circuits, for example soldering / reflow.

The conductors 48 and 49 have an intermediate portion bent, here at an obtuse angle, so that the bodies themselves, and therefore the emitter on one side and the receiver on the other side, are in angled positions with respect to each other and with respect to the body 45 The terminals 50 also have an intermediate folded portion, here with a substantially U-shaped (or alternatively S or Z-shaped) fold, to allow elastic assembly as previously indicated.

In various embodiments, the emitter 42 is associated with an optical filter or spatial filter 43, in particular in order to select or concentrate the light beam; an example of such a filter is illustrated in figure 10, with different views, together with the emitter 42. The spatial filter 43 is essentially a component made of plastic material that is not permeable to optical radiation or light, in particular molded, preferably mounted directly above the emitter 42; alternatively, the spatial filter 43 could be mounted or fixed to the body 46.

The filter 43 is preferably configured as a cap provided with an opening 43a in its opposite wall to the light source 42a of the emitter itself. This opening, which in Figure 10 is substantially in the form of a circular hole, filters and selects or concentrates the beam of light emitted by the emitter itself. The assembly of the filter body 43 preferably takes place by interference or hooking on the electronic component that forms the emitter 42: for this purpose, preferably, internal ribs or projections 43b are provided on the internal side of at least two opposite walls of the filter body 43 centering and / or fixing. Instead of a hole, the filter can be provided with an opening with a different shape suitable for the purpose, such as a slit (as illustrated for example in figure 38) or an oval or substantially square shape, said hole possibly having a sectional shape variable.

Figure 11 illustrates a possible electrical diagram of the module 40, for its connection to a relative interface circuit, here represented by the circuit arrangement 17 of the circuit support 15 (see Figure 4). As can be seen, the terminals 50 preferably allow to have as input and output signals a power supply level Vcc of the emitter 42, a ground GND and two voltage signals A and B relating to the two photo-detectors 44a and 44b. These signals A and B arrive at the circuit arrangement 17, preferably for a numerical processing on the controller MP (as also schematized in Figure 27).

In preferred embodiments, the bodies 45, 46 and 47 of the module are elements overmolded to the conductors 48, 49 and to the terminals 50. For this purpose, in various embodiments, a first visible semi-finished product SM1 is obtained from a substantially flat metal strip. in figure 12. The aforementioned strip can be, for example, made of copper or brass or other conductive metal, preferably coated at least in part with a metal material suitable to facilitate welding of the emitter 42 and receiver 44 components and / or of the circuit support 15 ( such as gold or tin).

The SM1 semi-finished product, obtainable for example by blanking from the aforementioned strip, defines in a single piece a flat shape of the conductors 48, 49 and terminals 50, which are joined together by accessory parts, some indicated with 49 'and 50'. On this semi-finished product SM1 the bodies 45-47 are molded, thereby obtaining a second semi-finished product, indicated with SM2 in figure 13. From the second semi-finished product SM2 the aforementioned accessory parts are then eliminated, for example by blanking, so as to define the conductors 48, 49 and the terminals, still in a flat configuration, as clearly visible in Figure 14. Next, preferably, the intermediate portions of conductors and terminals are bent, as explained above, to assume the configuration visible in Figures 7-9. Figures 15 and 16 exemplify a mold that can be used for forming the semi-finished product, the two parts of which HM1 and HM2 include respective cavities HM11 and HM21, suitable for positioning the starting semi-finished product SM1 of figure 12 and to define the profiles of the bodies 45-47 which must be overprinted on this semi-finished product.

In other embodiments, several bodies of an optical module, such as for example the bodies 45-47, can be elements overmoulded at least in part to a flexible printed circuit, which comprises or integrates at least part of the conductors (such as the conductors 48, 49) and terminals (such as terminals 50); or one or more bodies of a module, such as bodies 45-47, can be separately molded elements, particularly in polymeric material, and subsequently associated, for example by gluing, to conductors (such as conductors 48, 49) and terminals ( such as terminals 50) or to a flexible printed circuit comprising at least in part such conductors and terminals. For this purpose, several bodies of an optical module, such as bodies 45-47, can also be joined together by respective portions of flexible or articulated bodies, or made as a single body comprising the aforementioned bodies joined by body portions of reduced thickness. . In further embodiments, the bodies of an optical module can be molded elements comprising an insulating polymer, while the relative conductors and / or terminals can be molded elements in an electrically conductive material comprising a polymer, preferably co-molded or overmoulded together.

According to an inventive aspect, several bodies of an optical module, such as bodies 45-47, are printed positioning and / or fixing elements which can at least partially vary their relative position during module assembly. In particular, in various embodiments, such bodies, such as bodies 45-47, are capable of varying a respective relative angle, where this variation is also allowed by a flexibility of the relative conductors (such as conductors 48, 49) and / or terminals (such as terminals 50).

As explained, in various embodiments, the optical module 40 is connected in electrical signal communication with the electronics of the sensor device 10, particularly with the circuit arrangement 17 of the circuit support 15. In various embodiments, for this purpose the circuit support 15 has suitable connection elements, for the electrical connection of the terminals 50 of the module 40. Such connection elements can be, for example, in the form of one or more metallized holes, soldering pads, connectors provided with holes and small terminals, in correspondence with which the free ends of the terminals 50 are, for example, welded or electrically connected, as shown schematically in Figure 17, where the aforementioned holes are indicated with 53 (see also Figures 4-5 as a reference. In the example, the holes 53 (or the various connecting means which replace them) are in a generally central position of the support 15, which, however, must not be considered essential. As can be understood from this figure 17, the folded portion of the terminals 50 is elastically flexible or deformable, thus allowing to perform a function of spring, which allows to autonomously adapt the relative position between the module 40 and the circuit support 15.

Figure 18 shows an insertion step of the support 15, with the associated optical module 40, inside the body 10a of the device 10. In this figure, a possible realization of the positioning site 30 for the module 40 is visible.

The site 30 includes at least one protruding element or formation 31 which rises, preferably orthogonally, from the inner side of the wall 21 of the housing part 10a, intended to substantially perform optical prism functions. The formation 31 essentially consists of a wall - here substantially perpendicular to the inner side of the wall 21 - which is formed from the same material as the wall 21, in particular a transparent or permeable material to the light or optical radiation used by the optical module 40, and which is preferably divided by an intermediate cut or cavity 32 into two upright parts 33 and 34. The upright parts 33 and 34 are substantially specular to each other and each define an inclined face or surface 33a and 34a, in a lateral position, or in an external position relative to the intermediate cavity 32. In the exemplified case, the upright parts have an approximately triangular shape, in particular in the shape of a right-angled triangle, the hypotenuse of which form the aforementioned opposite inclined surfaces.

In proximity to the upper ends of the two upright parts 33 and 34, positioning appendages 35 generally parallel to each other rise in height, preferably having a section substantially complementary to that of the through openings 51a of the central body 45 of the module 40 (see reference figures 7-9). Preferably, in correspondence with the front and rear (or non-inclined sides) of the formation 31, a projection 36 is provided, which preferably surrounds the intermediate cavity 32, when the latter is provided (in the figure only the front projection is visible of formation 31, the rear projection can be of a similar shape). Preferably the projections 36 and / or the upright parts 33, 34 define abutment and / or positioning surfaces or seats 31a (Figure 18) for the optical module 40, particularly in an area from which the appendages 35 rise.

Preferably, although this is not strictly essential, the site 30 comprises two recesses or seats 30a defined in the bottom wall 21, each in correspondence with an upright part 33, 34, alongside the relative inclined surface 33a, 34a. Very preferably, in correspondence with at least one of the aforementioned recesses 30a, an element 37 is defined for positioning and / or centering and / or abutment and / or coupling for the lower end of a relative lateral body 46, 47 of the module 40, particularly for the relative lower projections 46b, 47b (see figures 8 and 9 for reference).

During the assembly phase, the support 15 with the associated optical module 40 is inserted inside the body 10a, with the support itself slipping between the seats 22, preferably until it reaches the internal side of the wall 21.

During this insertion, the upper appendages 35 of the upright parts 33, 34 (figure 18) insert themselves into the through openings 51a of the central body 45 of the module 40 (figures 7-9) and the wall 52a of the lower formation 52 of the same body central 45 (Figures 8-9) insinuates itself into the intermediate cavity 32 which separates the upright parts 33 and 34 of the optical formation 31 from each other (Figure 18). The walls 52b of the same formation 52 slide on the projections 36 of the front and rear of the formation 31 (Figure 18), contributing to the centering.

The vertical stop between the module 40 and the formation 31 is made in the upper part, with the lower surface of the central body 45 of the module 40 which abuts on the upper surfaces of the upright parts 33, 34, i.e. surfaces from which they protrude in height the appendices 35 (such surfaces can be seen in figure 18, two of which indicated with 31a). Preferably, at least one stop is made in the radial direction, also for positioning or anti-rotation purposes, of the optical module 40 with respect to the site 30: this stop is preferably obtained by means of the lower protrusions 46b and 47b (Figures 8 and 9) of the lateral bodies 46 and 47 of the module 40, which engage in the elements or seats 37 defined in correspondence with the recesses 30a (figure 18), possibly providing means for mutual coupling between the elements 46b, 47b and the elements 37. In this way the module 40 cannot rotate and can remain in the desired position.

The flexibility of the conductors 48, 49 and of the terminals 50 of the module 40 is particularly advantageous in this phase, since it allows to compensate for any dimensional tolerances in the manufacturing of the parts and in the assembly of the module itself on the circuit support 15, which are relatively high in devices comprising several parts molded in plastic material, thereby avoiding breakages during assembly and / or allowing precise positioning of the optical module 40.

A partially assembled condition is visible in figure 19, from which it can be seen how, in the position described, the body 46, and therefore the emitter 42, on one side, and the body 47, and therefore the photo-detectors 44a, 44b, on the other hand, they are facing and generally parallel to the inclined surfaces 33a and 34a of the two upright parts 33 and 34, respectively. Then, and as can be seen in Figure 20, on the formation 51 defined in correspondence with the upper face of the central body 45 of the optical module 40, the previously mentioned elastic locking and / or positioning element 60, hereinafter also referred to for simplicity as "spring ”, Preferably formed with metallic material. The spring 60 has a central part 61 provided with a finned hole (ie an opening defined by elastic radial fins), in order to allow it to be fixed with interference on the same formation 51. It is preferable that the fins of the hole are also sized to allow fixing with interference also with the external surface of the appendages 35 which protrudes in correspondence with the formation 51 (see Figure 20).

From the central part 61 of the spring 60, opposite elastic arms 62 radiate, generally curved, intended to exert a force on the lateral bodies 46 and 47 of the module 40. The ends 62a of the arms 62 are for this purpose preferably shaped to be received in the grooves 46a and 47a (Figure 7) of the side bodies 46 and 47 of the module 40, respectively. Preferably the aforesaid ends 62a are curved, also in order to be able to slide in the grooves 46a and 47a during assembly. As can be understood, in this way, the optical module 40 is fixed in position relative to the formation 31 (and / or to the site 30 and / or to the inclined surfaces 33a, 34a and / or to the wall 21 and / or to the body 10a), as shown in figures 20 and 21.

The force exerted by the arms 62 of the spring 60 is capable of flexing the conductors 48, 49 of the module 49 (Figures 7-9), ensuring that the bodies 46 and 47 abut against the body 10a; for this purpose both the configuration of the conductors 48, 49 and the configuration of the spring 60 are predefined to ensure said bending of the conductors and / or said positioning. Referring to Figure 21, the force exerted by the spring 60 ensures, on the side of the emitter 42, the stop and positioning between the spatial filter 43 and the optical surface represented by the inclined surface 33a. On the side of the receiver 44a-44b, the force of the spring 60 ensures the abutment between the lower projection 47b of the body 47 of the module 40 and the relative abutment 37 defined in the wall 21.

The insertion of the two aforementioned stops in conjunction with the use of the spring 60 guarantee a recovery of any tolerances for assembly and construction of the components, in such a way as to have a precise position of the optical components 42 and 44a, 44b. The position of these components - which is linked to the critical angle expected by the application, as described below - influences the calibration of the liquid solution quality sensor and must therefore be defined and precise, in order not to generate measurement errors. The spring 60 also guarantees a recovery of play and deformations that can be generated during the life of the device 10, due to thermal cycles and / or aging of the materials. Obviously, the flexibility of the conductors 48, 49 and of the terminals 50 also contribute to the recovery of tolerances and clearances.

In preferred embodiments, the intermediate cavity 32 of the formation 31 is provided in order to shield the receiver 44, i.e. the photo-detectors 44a, 44b, from direct illumination by the emitter 42 (i.e. without affecting the solid interface surface -liquid, as clarified below). This cavity 32, when provided, could therefore not have the sole centering function for the optical module 40 but, also thanks to the interposition of the wall 52a of the lower formation 52 of the module 40 (see again Figures 8-9), could cause so that this wall acts as a screen against parasitic emissions, as can be clearly understood for example from figure 21. Possibly the walls of the intermediate cavity 32 or of some walls of the formation 31 can be at least partially coated with a material or paint impermeable to optical radiation , or shaped so as to deflect the beams of the emitter 42 so that they do not reach the receiver 44 directly.

Preferably, the shielding from direct emissions is further improved by the use of the spatial filter 43. The use of at least one of these shielding elements represented by the cavity 32 and / or the filter 43 could allow the use of less valuable emitters 42 and expensive, as they are not designed or selected for emissions within a narrow angle. Such an emitter 42, in fact, could be of the type which emits in a distributed manner in all directions (0-180 ̊) and, in addition to the spatial filter 43, the intermediate screen represented by the wall 52a prevents the light rays not involved in the measurement (i.e. the rays other than those reflected and refracted by the surface at the solid-liquid interface, as explained below) can alter the measurement performed by the photo-detectors 44a, 44b.

The operation of the quality optical sensor integrated in the device 10 according to the invention is linked to the optical laws related to the refraction / reflection of optical radiation, and in particular to the critical angle of total reflection. More particularly, the operating principle is based on the dependence of the refractive index of the liquid substance on its composition or concentration: the measurement is therefore based on the index jump between the liquid to be analyzed and the solid material in which the optical formation is defined. 31 and the relative part of the bottom wall 21 of the body 10a (ie its part involving the optical positioning site 30 of the optical module), exploiting the principle of total internal reflection at the interface between the two means.

If we consider:

- n1 as the refractive index of the aforementioned solid material (for example for a COC at 25 ° C, n1 = 1.5413 at a wavelength of 650nm),

- n2 the refractive index of the liquid solution, which will have a range of variation between two limits as a function of its concentration (for example, for urea we consider a range of variation between 1.3626 and 1.3949 corresponding to a concentration between 20% and 40%),

- θ 1� the angle of incidence (propagation of light in the solid), e

- θ 2 the angle of deflection of the refracted beam (propagation of light in the liquid), the angle of propagation in the liquid medium will depend on the angle of incidence at the interface of the propagating beam in the solid medium, as expressed by Snell's law:

1)

The reflection coefficient at the interface between the two materials as a function of the angle of incidence for polarization p (parallel) and s (normal) of the light is expressed instead by Fresnel's law:

2)

The intensity of the reflected ray is made up of the composition of the two states Rs and Rp. By calculating 2) and 3) for each angle of incidence and for each value of the refractive index of the liquid solution in the range of variation of interest, it is possible to know the entity (%) of the reflectivity as a function of the angle of incidence of the light beam. The angle of incidence at which the relations 2) and 3) generate a reflectivity value equal to 100% is called the total internal reflection critical angle.

Since there is a limit condition for the angle of incidence at the solid-liquid interface, for which the angle of refraction is tangent to the interface itself, n1 must be greater than n2, as in the situation of interest for the application considered here, in which the propagation from solid to liquid is considered. For incidence with an inclination greater than the critical angle, the beam is totally reflected at the interface.

It can be deduced that the critical angle of refraction at the interface is expressed by the relation

which represents the condition at which the reflectivity value - when the angle of incidence θ 1 calculated with equations 2) and 3) varies - reaches 100%.

By calculating 4) for all the values of n2 of interest, since n2 is the refractive index of the liquid solution which depends on its concentration, it is possible to link the value of the concentration to be measured to the position of the light beam reflected at the solid interface -liquid.

In particular, the following relationships are valid:

If Conc1 � Conc 2 then the relation holds

On the basis of what is mentioned here, it is therefore possible to exploit the existence of a critical angle of total reflection that varies with the variation of the concentration to measure the latter, using the relationships 5).

For this purpose it is possible to use a light source - i.e. an emitter 42 - with a diverging output, in order to illuminate the interface surface at all angles of interest around the critical angle, and therefore with greater and lesser incidence than the critical angle. . In this way there will be two areas: an area affected by the totally reflected rays (linked to those with an incidence greater than the critical angle) and an area affected with less intensity, which is illuminated by partially reflected rays (linked to those with an incidence lower than the critical angle). critical angle). It is thus possible to obtain, at the output, an intensity field in which the separation between the highly illuminated area by total internal reflection and the less illuminated one (partial reflection) is variable in the concentration of the liquid.

Therefore, using the two photo-detectors 44a and 44b, positioned in the two zones, through the variation of their output signal it is possible to evaluate the variation of the critical angle and consequently the variation of composition or concentration - and, ultimately - of the quality of the substance or liquid solution.

The inclination of the optical surfaces 33a and 34a is preferably calculated so that the optical signal crosses them in a direction as orthogonal as possible with respect to the light input and output surfaces, so as to minimize the reflection at the air-solid and solid interfaces. air, respectively.

The emitter 42 is preferably a light source with a narrow emission beam, to concentrate the measurement in the area of interest (around the critical angle), according to the direction identified as a function of the critical angle (however, as previously indicated, the preferential use of filters and / or screens also allows the use of light sources with a wider emission beam). In this way, interference due to direct lighting on photo-detectors 44a and 44b is also minimized. In various embodiments, sources with non-diffused Lambertian emission are preferable, i.e. light emission uniform in space and free from holes or alterations in the near field. To exploit the almost constant zone of maximum intensity of the source and restrict the emission in the area around the critical angle, the spatial filter 43 is preferably also introduced.

The schematization of the light rays can be represented as exemplified in figures 22 and 23.

These figures show two rays R1 and R2 contained within the emission field of the source, which are incident on the separation surface between solid and fluid (i.e. the external side - here indicated with 211 - of the bottom wall of the cavity H ) with two different angles; the angles of the rays R1 and R2 are respectively lesser and greater than the critical angle. The R1 ray, being incident with an angle lower than the critical angle, will be refracted in the R11 ray and reflected in the R12 ray. For the conservation law, the intensity of the R1 ray will be divided between the R11 ray and the R12 ray. The ray R12 will be detected by a first photo-detector 44a, hereinafter also referred to for simplicity as an upper photo-detector. The radius R2, on the other hand, is incident with an angle greater than the critical angle and therefore will be totally reflected in the radius R21. Unless dissipated, the R21 ray will have the same intensity as the R2 ray. The totally reflected ray will be detected by the second receiver 44b, hereinafter also referred to as the lower photo-detector for simplicity.

The rays used for the schematic representation of figures 22 and 23 are part of an illuminating field that changes its configuration as a function of the variation of the critical angle (i.e. the refractive index of the liquid solution), i.e. the concentration of the solution liquid. In figures 24, 25 and 26 three working conditions are exemplified for greater clarity, linked to three different concentrations of the fluid.

In the presence of a substance or liquid solution with a first composition or concentration "Conc 1" we have the schematization of Figure 24: assuming that the rays of the R beam strike the interface surface with an angle equal to the critical angle, the R1 rays , R2 and R3 are obtained as a total reflection of the incident rays, while the R4 and R5 rays are obtained as a partial reflection of the incident rays. The lower receiver 44b will therefore be completely illuminated by the totally reflected rays, while the upper receiver 44a will have a lower illumination produced by the partially reflected rays.

Figure 25 schematises a condition in which a second concentration of the substance or liquid solution is equal to "Conc 2", where Conc 2 is less than Conc 1. The rays of the illuminating beam R produced by the emitter 42 always strike at the same angle , while the critical angle decreases. It follows that, in addition to the rays R1, R2 and R3, the ray R4 will also be obtained by total reflection while the ray R5 will continue to be obtained by partial reflection. In this condition, the illuminating intensity on the upper receiver 44a will be increased, while that on the lower receiver 44b will be unchanged.

Finally, Figure 26 schematises a condition in which a third concentration of the substance or liquid solution has a value of "Conc 3", which is greater than Conc 1. Also in this case, the rays of the illuminating beam R produced by the emitter always affect the same angle, while the critical angle is increased. It therefore follows that the rays R1 and R2 will always be obtained by total reflection, while the ray R3 will be obtained by partial reflection like the rays R4 and R5. In this condition, the illuminating intensity on the upper receiver 44a will be decreased, while that on the lower receiver 44b will be unchanged. By further increasing the concentration of the fluid, the percentage of rays totally reflected will decrease, also varying the signal on the lower receiver 44b. In this condition, the illuminating intensity on the upper receiver 44a will be decreased, while that on the lower receiver 44b will be unchanged. By further increasing the concentration of the fluid, the percentage of rays totally reflected will decrease, also varying the signal on the lower receiver 44b.

As can be seen, therefore, the photo-detectors 44a and 44b are positioned so as to each receive a part of the reflected light beam, one at high intensity, which is hit by the incident light with an angle greater than the critical angle, and the another at low intensity, which receives the light on the "tail" of the illuminating profile.

On the basis of the above, if A and B are the voltage signals at the output of the photo-detectors 44a and 44b, it is easy to understand that they contain a term that depends on the optical power P emitted by the source 42. A and B are in fact, voltage signals generated by the photo-current value, or electric current of the illuminated photodetectors, multiplied by the transimpedance gain. The photo-current is proportional to the optical power P emitted by the source 42, multiplied by the response (responsiveness) of the photo-detector 44a or 44b, that is:

A = ka * P * response * transimpedance

B = kb * P * response * transimpedance

where ka and kb are coefficients that take into account the amount of light incident on the photo-detector 44a or 44b, which will be a function of the refractive index and therefore variable according to the critical angle.

To eliminate the dependence on P and thus obtain a signal that depends only on the position of the centroid of the illuminating field, regardless of the value of the peak intensity, it is sufficient to introduce a normalized signal. This signal can be correlated, for example by means of an appropriate calibration carried out on the basis of predefined data, to the variation in concentration of the substance or liquid solution subject to detection, which is therefore independent of the illuminating power P. It is convenient to eliminate the dependence on the intensity of the optical power. so that the measurement is not affected by disturbances linked to variations (for example thermal or degradation over time) in the emission of the source 42.

The two signals A and B produced by the photo-detectors 44a and 44b are preferably treated by an analog conditioning network, to be adapted to the electronic controller MP capable of generating a signal S, directly correlated through appropriate calibration to the concentration of the liquid solution. .

Figure 27 shows an example of an operating block diagram of the optical quality sensor. In this figure, Vcc indicates the low voltage power supply of the emitter 42, while the OG block is intended to represent the optical geometry given by the positioning site 30 (formation 31 and its portion of the wall 21). As can be seen, the voltage signals A and B in output from the photo-detectors 44a, 44b are treated by a conditioning circuit CC and the conditioned signals A1 and B1 reach the relative inputs of the controller MP, which generates the signal S representing the concentration value of the solution. The components CC and MP are preferably located on the circuit support 15, with the controller MP managing the quality detection of the substance or liquid solution; the CC and MP components can also be integrated into a single microcontroller component.

In various embodiments, the connection between an optical module of the device 10 according to the invention and the related interface and / or control circuit, such as that made on the circuit support 15 and / or by the circuit arrangement 17, can be achieved by means of a wiring, or electrical wires, instead of terminals, preferably wires provided with external insulation. An embodiment of this type is illustrated for example in figures 28-33, in which the same reference numbers as in the previous figures are used, to indicate elements that are technically equivalent to those already described above.

The use of electrical wires allows to keep the circuit support 15 and the optical module separate, in order to be able to mount them separately, to make the wired connection between them after the assembly of the two parts. Preferably, and as can be seen in particular in figures 31-33, the connection holes 53 are provided in lateral positions of the circuit 15, to which the aforementioned electric wires - some of which indicated with 501 in figure 33 - can be welded, for example. . The holes 53 can also be replaced by metallized pads or small clamps. The dimensions of the circuit 15 can also be different with respect to the previously illustrated case.

In view of the use of electrical connection wires, the body 45 of the optical module 40 is slightly modified with respect to that previously illustrated. In particular, the terminals previously indicated with 50 are shorter and are mainly embedded in the plastic material which constitutes the body 45 (see, for simple reference, figures 37 and 38, as far as they relate to a further embodiment). Preferably, these terminals have through holes (or pads) in respective end regions and the central body 45 of the module 40 is molded in such a way as to leave the aforementioned holes (or pads) accessible, as can be seen for example in Figures 31 and 32, where 502 indicates some of the passages of the body 45 which allow access to the aforementioned holes of the embedded terminals, in order to allow the connection of the electric wires (for this type of embodiment, see also figures 38 and 50 for example).

In embodiments of this type it is preferable that the circuit support 15 is first inserted into the seats 22 and then the optical module 40 is positioned and fixed on the formation 31, in a substantially similar way to what has already been described above, by means of the spring 60. The electrical wires 501 are then connected between circuit 15 and module 40. The wires 501 can also be connected on the optical module 40 before its assembly on the formation 31. The operating principle of the device, as regards the detection of the quality of the liquid solution is similar to that previously described.

The advantage of solutions which involve the use of electrical connection wires offers greater flexibility in the coupling between the optical module 40 for measuring the concentration and the printed circuit 15 (however, instead of the aforementioned electrical wires, other connections could be provided or electrical terminals, for example in the form of terminals obtained from sheared metal strip or stamped or machined metal; this type of electrical terminals could possibly have an overmoulded body, distinct from the bodies 45-47 of the optical module 40).

In various embodiments, an optical screen is provided inside the cavity of the body of the sensor device, preferably of a dark color or impermeable to light or to a predefined optical radiation, which acts as a screen from ambient light.

Figures 34-48 show a variant of embodiment in this sense. Also in these figures the same reference numbers of the previous figures are used, to indicate elements technically equivalent to those already described above, particularly as regards the relative position between the formation 31 and the opening 22, as well as for the type of electrical connection of the optical module 40 to the circuit 15, or its arrangement 17. The embodiments described with reference to figures 34-48 are essentially characterized by the presence, inside the cavity H, of a screen or body aimed at limiting the diffusion of the ambient light, as well as by a different fixing method in position of the optical module 40, with respect to the previous embodiments.

Referring initially to Figure 34, the body 10a and the circuit support 15 can be of substantially similar construction to that described with reference to Figures 2-27, as well as the basic structure of the formation 31, whose upper appendages 35 have external recesses .

The optical module 40 is substantially similar to that of figures 28-33, possibly with some modifications depending on its method of fixing in position: for example, in various embodiments, the module 40 can be secured in position by means of a different elastic element or spring 601 and a stop or retaining ring 80, particularly a snap ring or a Seeger ring.

The aforementioned optical screen, indicated as a whole with 70 in Figure 34, is represented in detail in Figures 35-36. The screen 70 has a body 71 preferably formed with material not permeable to optical radiation of predefined wavelengths, such as a dark material or in any case such as to limit or prevent the passage of ambient light. The body 71 has a bottom wall 72, intended to rest on the wall 21 of the body 10a, and a peripheral wall 73, preferably but not necessarily with a profile corresponding to at least a part of the peripheral wall 20 of the body 10a (Figure 34). In the example, this profile is semicircular, with a diameter slightly smaller than that of the wall 20, or possibly such as to allow insertion with slight interference.

In the bottom wall 72 a passage or lateral recess 72a is defined, shaped in such a way that the wall 72 does not interfere with or cover the positioning site 30 of the bottom wall 21 of the body 10a. Within this recess, a substantially frame-like structure 74 protrudes projecting, intended to be fitted on the optical formation 31. For this purpose, the structure defines two upper openings 74a, into which the upright parts 33 and 34 of the optical formation 31, these openings being separated from each other by an intermediate wall 74b, capable of being received in the intermediate cavity 32 of the formation 31 (see Figure 39, for reference to the aforesaid upright parts and intermediate cavity).

The frame structure 74 of the screen 70 further has lateral passages 74c, intended to face at least part of the inclined optical surfaces 33a and 34a of the formation 31.

The optical module 40 is instead illustrated in figures 37 and 38. As can be seen, its basic structure is similar to that of the module in figures 28-33. In various embodiments, the central body 45 of the module 40 defines an opening 45a, for positioning a stop element of a spring 601, in particular defined between the upper formation 51 and the area in which the passages 502 are defined for the connection of the electrical wires (hereinafter referred to as 501) for interfacing with the circuit 15. Again preferentially, on at least one side of the opening 45a, the upper face of the central body 45 has a protrusion 45b which acts as a stop for the stop ring 80 (Figure 34).

For assembly purposes, the screen 70 is inserted into the cavity H of the body 10a with its bottom wall 72 facing the bottom wall 21, as in Figure 39, so that in the passages 74a of the frame structure 74 of the same screen the upper appendages 35 of the optical formation 31 insinuate and the intermediate wall 74b of the screen insinuates itself into the intermediate cavity 32 of the same formation 31. Following the positioning of the screen 70, as shown in Figure 40, the recesses or seats 30a and any further parts of the optical site 30 remain exposed (through the recess 72a of the screen); the lateral openings 74c also face the inclined optical surfaces 33a and 34a of the optical formation 31.

The circuit 15 is then inserted into the seats 22 and the module 40 is fitted on the formation 31, similarly to what has already been described above, as shown in figure 41. The fixing can be carried out using a spring of the type previously indicated with 60. In alternatively, the spring 601 is positioned on the upper formation 51 of the module 40, having a slightly different shape from those previously indicated with 60, but having substantially similar structure and functions, and this spring is then locked in position by means of a ring 80, as can be seen in Figure 42. Subsequently, the module 40 is connected to the circuit 15 by means of the electric wires 501, similarly to what has already been described previously, as can be seen in Figure 43.

As mentioned, the plastic component 70 acts as a screen from the ambient light, referable to any optical emission external to the device 10 and / or to the optical module 40. Given that the operating principle of the optical quality sensor is based on the detection of rays luminous or optical, the possibility of having “parasitic” ambient light that affects the liquid solution and / or the photo-detectors 44a, 44b can disturb the measurement. This condition can be verified, for example, with the application of the device according to the invention on transparent or non-opaque tanks, or by making the entire body 10a of the device 10 in a material permeable to optical emissions or to light: ambient light can then illuminating the fluid and / or the photo-detectors 44a, 44b through the walls of the tank and / or parts of the body 10a and thus disturbing the measurement. The plastic screen 70, mounted inside the body 10a, allows for example to screen the ambient light, thereby eliminating the risk of disturbance due to ambient light.

Figure 44 shows a possible embodiment of the spring 601. Also in this case the structure of the spring includes a central part 61, from which two opposite arms 62 branch off, the ends of which are shaped for engagement in the relative seats 46a, 47a provided on the external face of the lateral bodies 46, 47 of the module 40 (see figures 37-38); preferably, said ends 62a are curved, also in order to be able to slide in the grooves 46a and 47a during assembly.

In this case, preferably, the central part 61 has a hole or opening whose profile substantially corresponds to the external profile in plan defined by the upper formation 51 of the module 40 and by the upper appendages 35 of the optical formation 31 (it should be noted that in this case realization the passages 51a of the body 45 of the module 40 - figures 37-38 - and the aforementioned appendages 35 are configured in such a way that these appendages protrude appreciably laterally beyond the external profile of the formation 51: see reference figure 41) . Furthermore, from one side of the central part 61 of the spring 601, here the front side, protrudes a stop element 61b, here in the form of a flap folded downwards, in the form of a tooth.

Figure 45 shows a possible embodiment of the stop ring 80. In preferred embodiments, the ring 80 is substantially a ring of the Seeger type, that is a ring - preferably metallic, very preferably made of elastic steel - having a generally flat configuration and whose circumference is not complete and where, in its two end regions, holes are defined for the insertion of a suitable assembly pliers, such as a Seeger pliers. In the case illustrated, according to an inventive characteristic per se, at least the internal profile of the ring 80 substantially reproduces part of the profile of the opening 61a of the spring 601 and / or is complementary to part of the aforementioned external profile in plan of the upper formation 51 and from the upper appendages 35, thus presenting a substantially circular profile with two opposite projections or recesses 80a. At one end, beyond the relevant hole, the ring 80 defines a projection or stop seat 80b. Preferably, moreover, the other end provided with a hole in the ring defines an external abutment surface 80c. At least one of the projection or seat 80b and the stop 80c define anti-rotation means for the ring 80.

It should also be noted that, particularly from Figure 40, in various embodiments of the invention the upper appendages 35 of the formation 31 have, in their upper end region and in correspondence with their outer side, a lateral recess, indicated with 35a (si see, for simple reference, also figure 79).

As already highlighted, the spring 601 performs the same functions already described previously, but its assembly does not occur by interference on the formation 51 of the optical module 40, being blocked by the ring 80. Figures 46-48 show a possible sequence assembly of spring 601 and relative stop ring 80.

After the module 40 has been fitted on the optical formation 31, preferably with the structure 74 of the screen 70 interposed, the spring 601 is fitted on the module, so that in its central opening 61a (see figure 44) the formation 51 and the protruding part of the appendages 35, as in figure 46. With this insertion, moreover, the element 61b of the spring engages in the opening 45a of the central body 45 of the optical module 40, thereby performing anti-rotation functions of the spring 601.

The ring 80 is then fitted onto the formation 51 and the appendages 35 in an angular position which allows such insertion, as in figure 47. In practice, in this angular position of the ring 80, its two protrusions or recesses 80a ( figure 45) are in correspondence with the appendages 35, ie the internal profile of the ring 80 corresponds to part of the external profile defined by the formation 51 and by the appendages 35. Subsequently, for example, using the two holes of the ring 80 and a normal gripper Seeger, the ring itself is made to rotate, so that it engages the lateral recesses 35a of the appendages 35 (see figure 40), and until its stop projection 80b and the stop surface 80c meet the projections 45b defined on the upper face of the body 45 of the module 40. This final locking situation is shown in figure 48.

The locking system described with reference to figures 44-48 makes it possible to reduce the dimensions of the spring and avoid its fixing by mechanical interference, which could cause possible problems of breaking or damaging the plastic material which forms the formations 31 and / or 51. This type of fastening of the spring is independent of the presence of an optical screen of the type indicated with 70 and can also be used in the other embodiments described here which provide for the use of an optical module substantially of the type indicated with 40 and / or other devices. As mentioned, however, nothing prevents in principle from using an elastic fastening element of the type described with reference to the previous Figures 2-33 also in the device of Figures 34-48. Furthermore, a screen of the type described, also having a shape different from the one exemplified, but with the same purposes, can be used in all the embodiments described here.

In various embodiments of the invention, a fastening element of an optical module is configured to be secured in position, relative to an optical formation, by its angular movement. Possible embodiments of this type are described with reference to figures 49-60. Also in these figures the same reference numbers of the previous figures are used, to indicate elements that are technically equivalent to those already described.

As can be seen in figures 49-50, in various embodiments, lateral bodies 461 and 471 of the module 40 are provided which have, in correspondence with at least one lateral region, an opening surface 46c, 47c, for example an inclined plane or a surface curve, which extends towards the upper face of the same body. Preferably, the lead-in surface 46c is defined in the body 461 in the opposite position to the lead-in surface 47c defined in the body 471. For the rest, the construction of the optical module 40 is substantially similar to that described with reference to previous embodiments, with the central body 45 which defines the formation 51 at the top and the formation 52 at the bottom, with the through openings 51a. Also in this case the terminals 50 are preferably mostly embedded in the plastic material of the body 45 and have welding pads or holes aligned with passages 502 of the body 45 in respective end regions.

In preferred embodiments, in correspondence with at least one edge of the body 45 - here the front edge - a positioning recess 45a1 is defined, the functions of which will become clear in the following. Also the site 30, that is the optical formation 31 (Figures 58-59), is similar to that described with reference to Figures 32-44, particularly as regards the presence of lateral recesses 35a in correspondence with the upper end regions of the appendages 35 .

Also in embodiments of this type, the module 40 is grafted onto the formation 31 in a manner similar to those previously described, but the fixing is achieved by means of an elastic locking and / or positioning element of different configuration, a possible embodiment of which is visible in figure 51, where this element or spring is indicated as a whole with 602.

Also in this case the elastic element 602 has a central part 61 provided with a through hole 61a and two opposite arms 62 elastically flexible. Preferably, the distal ends 62a of these arms 62 are folded or in any case shaped to facilitate their sliding on the bodies 461 and 471, in particular in an angular or rotary direction, as described a little further on. The part 61 is shaped so as to define two flexible fins 61c within the hole 61a, in opposite positions, preferably in positions generally corresponding to those of the arms 62. The fins 61c, here having substantially arched configuration, follow each part of the profile of the hole 61a, this profile also having a pair of enlargements in diametrically opposite positions, each substantially in correspondence with the free end of each fin 61c. Preferably, moreover, an appendage 61e departs from the central part 61, generally transverse or orthogonal with respect to the arms 62. The elastic element 602, as well as those previously described, is preferably made of metal, starting from a strip sheared and deformed.

As visible in figures 52 and 53, the hole of the element or spring 602 is fitted on the formation 51 of the module 40 and on the protruding part of the appendages 35 that protrudes on the sides of this formation. This is allowed by the presence of the enlargements 61d, which in this phase are in positions corresponding to the aforementioned appendages. Then the spring is rotated (counterclockwise, referring to figures 53-57), in such a way that first the edge of the spring hole - figure 54 - and then that of the fins 61c - figure 55 - fits into the recesses 35a of appendices 35 (see also figures 58-59 for reference). At a certain point of the angular movement the free ends of the spring arms 60 come into interference with the driving surfaces 46c and 47c, as shown in Figure 55. As mentioned, the ends 62a of the arms 62 are preferably curved or shaped to facilitate sliding and / or avoiding jamming: in the example, these ends are folded substantially in a C.

The continuation of the angular movement of the spring 602 is therefore allowed by the presence of the inclined or curved leading surfaces 46c, 47c, which in this phase act as a slide, with the ends 62a of the same spring which can slide right on the upper face of the bodies 461 and 471, as shown in figure 56. In this way an elastic flexion of the arms 60 is determined, or their pre-load, which stresses the bodies 461 and 471, and therefore the module 40 as a whole, on the relative formation 31: the optical filter 43 - and therefore the body 461 - is elastically pressed on the inclined surface 33a, while the lower appendage 47b of the body 471 is elastically pressed on the relative abutment 37 (see reference figure 58).

When the ends 62a of the two arms 62 of the spring 602 are in substantially central positions of the upper faces of the bodies 461 and 471, that is, the spring 602 is in the correct position, in the recesses 35a of the appendages 35 the terminal end regions of the fins 61c are in any case engaged , and the appendix 61e which departs frontally from the spring 602 is aligned with the recess 45a1, as visible in figure 56. The spring can then be secured in position causing a plastic deformation of the appendix 61e, in the sense of engaging it in the recess 45a1, as visible in figure 57. Subsequently, the circuit 15 can be inserted in the relative seats 22 (figure 52), as visible in figures 58-59. Thereafter, the optical module 40 can be electrically connected to the circuit 15 by means of the electric wires 501, as in Figure 60, in the manner already described.

Of course, the fastening system described with reference to figures 49-59 can also be used in other embodiments described herein of the device in accordance with the invention.

In embodiments described up to now, the optical radiation emitter 42 and receiver 44a-44b of the optical module 40 are positioned at the lower face of the relative supporting bodies 46 or 461 and 47 or 471. However, in various forms of implementation, an opposite configuration is possible, ie with emitter and receiver in correspondence with the external face of the aforesaid support bodies. Possible embodiments of this type are described with reference to figures 61-71, which use the same reference numbers of the previous figures, to indicate elements that are technically equivalent to those already described above.

In various embodiments of this type, the emitter and receiver electronic components used have a respective casing or package, of the type commonly referred to as "reverse gullwing". This possibility can be advantageously exploited to integrate a spatial filter - for example of the types previously indicated with 43 - directly into the structure of the optical module 40, assembling the emitter 42 and / or the receiver 44a-44b in correspondence with the external face of the relative support bodies 46, 47. The operating principle of the module 40 does not change with respect to the versions described above and also the basic elements of the optical sensor preferably maintain the same characteristics already described, even with slightly different shapes. The spring used can be of the type previously indicated with 60.

As can be seen particularly in figures 62-63, the structure of the module 40 is substantially similar to those described above, that is with the central body bodies 45 and the side bodies - here indicated with 462 and 472 - overmolded with conductors 48, 49 and terminals 50. In the exemplified case, the lower formation of the central body 45, indicated here with 521, is slightly modified with respect to the previous versions, but in any case distinguished by the presence of the transverse wall 52a intended for coupling with the relative intermediate cavity of the optical formation 31. For centering and resting relative to the formation 31, the walls 52b of the embodiments illustrated above are replaced by projections 52b1 and by homologous axial ribs provided on a wall 52b2 which extends orthogonally downwards from the lower face of the body 45. This wall 52b2 - which can have a height such that its lower edge rests on the wall te 21 of the cavity H of the body 10a in order to provide a support for the module 40 - advantageously also performs the functions of a rear screen from ambient light, being bodies 45-47 preferably formed with dark material or in any case not permeable to light and / or predefined optical radiation .

The lateral bodies 462 and 472 are equipped with through openings 46d and 47d, in order to allow the passage of the light radiation, as can be seen in particular in Figure 63. According to an aspect which is inventive in itself, the body 462 or at least the opening 46d also carries out the functions of the spatial filter described above, i.e. the body 462 of the module 40 defines at least one passage or hole, preferably circular or slit-shaped, which filters and selects or concentrates the beam of light emitted by the emitter 42.

The assembly of the electronic components 42 and 44a-44b on the upper surface of the bodies 462 and 472 entails the need to introduce a protective surface in the area where the spring 60 must exert its pressure. To prevent the spring 60 from exerting the force directly on the aforementioned electronic components, in various embodiments a protection element is used, indicated as a whole with 90 in figure 61, which can advantageously also perform the functions of a screen from ambient light: the spring will exercise therefore the force on the protection element 61 and indirectly also on the module 40. Note that, since the spatial filter 43 is no longer present, it is preferable to also obtain a stop between the lateral body 462 and the formation 31, to always guarantee the correct positioning of the components: for this purpose, the lower appendage 46b of the body 462 (see figure 63) and the relative positioning element 37 are configured to define this stop and / or the reciprocal positioning (see for example figure 70).

A possible embodiment of the protective element or screen 90 can be seen in figure 64. Referring to the illustrated example, the screen has a plastic body 91, preferably dark or not permeable to light, having a generally annular open shape - here approximately elliptical - in to which a bottom wall 92 and a peripheral wall 93 are defined. From the bottom wall 92 a front wall 94 rises which, in the mounted condition of the device, faces the positioning area of the emitter 42 and of the receiver 44a. 44b, to create a front screen for ambient light. The screen 90 is shaped so as to define upper appendages 95, generally inclined in opposite positions, which define on their external surface seats 95a for the ends of the opposite arms of the spring 60. The appendages 95 are shaped so as to define a sort of seat housing and protection of the emitter 42 and of the photo-detectors 44a, 44b, as will become apparent hereinafter. The lower wall 92 is shaped so as to define an axial passage, for mounting in position of the screen 90 after the module 40 has been mounted on the relative formation 31. For this purpose, the peripheral wall 93 also has an interruption 93a.

In case of use of the screen 90, it is preferable that on the bottom wall 21 of the cavity H there is at least one element for positioning or abutment of the screen itself, since the spring 60 exerts its own pressure on it. In the case shown - see figures 65-66 in particular, at least one positioning element 21a is provided for this purpose, consisting of a wall that rises from the bottom 21 of the cavity H, this wall 21a here having a curved shape, corresponding to part of the external profile of the peripheral wall 93 of the screen 90. The opposite part of the profile of the peripheral wall 93, here comprising two sections separated by the interruption 93a, conforms to that of the peripheral wall 20 of the cavity H: thus the screen 90 can be positioned between the element 21a and the peripheral wall 20. In the illustrated example, furthermore, further abutments or abutments 21b for the screen 90 are also defined in the bottom wall 21 of the cavity H, at the opposite ends of the site 30.

For assembly purposes, the module 40 is fitted onto the formation 31 in a manner similar to those already described above, as schematized in figures 65-66, after which the screen 90 is positioned inside the cavity H of the body 10a, as schematized in the Figures 66 and 67. The presence of the interruption 93a in the peripheral profile of the screen 90 is aimed at allowing or facilitating the assembly of the screen itself after fixing the module 40.

After mounting the shield 90, the module 40 can be fixed in position by means of the elastic element 60, as shown in figure 68, and then the circuit 15 is positioned in the relative seats 22 and the connection is made through the electric wires 501 , as shown in Figure 69. Advantageously, the wires 501 can be welded to the module 40 before fixing them to the body 10a and / or the terminals 50 could comprise electrical connections of the rapid type and / or of the insulation piercing type.

The assembled condition is clearly visible in the sections of figures 70 and 71. In particular from figure 70 it can be seen how the lower projections 46b and 47b of the bodies 46 and 47 are inserted in respective positioning seats 37 and / or abut on relative stops, in order to ensure the precise positioning of the bodies 462 and 472, and therefore of the emitter 42 and the photo-detectors 44a, 44b, relative to the inclined surfaces 33a and 34a of the formation 31. The positioning accuracy is made possible thanks to the flexibility of the conductors 48, 49 which connect the bodies 462 and 472 to the central body 45. The module 40 is kept in position thanks to the spring 60, whose finned hole engages with interference on the formation 51 and on the outside of the appendages 35 causing a thrust on the screen 90 and on module 40. The screen 90 is positioned in the aforementioned ways, between the elements 21a, 21b (figures 65-66) and the peripheral wall 20 of the cavity H, and is kept in position thanks to and to the arms 62 of the spring 60, which are engaged in the external seats 95a of the appendages 95 of the screen (see reference figure 64). As can be seen, in the assembled condition, the appendages 95 of the screen perform the protection function for the emitter 42 and the photo-detectors 44a, 44b.

The operation of the device of figures 61-71, as regards the detection of the quality of the liquid solution, is similar to that of the previous embodiments.

In embodiments described up to now, the sensor device according to the invention has its own casing, including the body 10a and the lid 13. In other various embodiments, at least a part of this casing can be defined by a different body, which it belongs to a different element or component to which the device is associated. Embodiments of this type are described with reference to the example of figures 72-78, which use the same reference numbers of the previous figures, to indicate elements that are technically equivalent to those already described. In the case illustrated, the device according to the invention is coupled to a level sensor, but in other embodiments the device according to the invention could be mounted on, or at least partially integrated in, a device or component UDM or a heater of the type previously mentioned.

Figures 72-78 show an example in which the body or casing of the device according to the invention comprises at least a first body of a level sensor 110, such as the body indicated with 110a, and a second body of an optical sensor, such as the body indicated with 10a, which are associated with each other in a sealed manner, preferably with the interposition of at least one further body or a sealing element and / or by welding or gluing; optionally, at least one body or a sealing element is molded to at least one of the first body 110a of a level sensor 110 and the second body 10a of a sensor or optical group 10.

In various embodiments at least the aforementioned first body is made with a thermoplastic polymer (for example HDPE) or a thermosetting polymer (for example an epoxy resin), while the aforementioned second body is made with a thermoplastic polymer (for example PSU or COC ); the aforesaid further body is preferably formed with an elastically compressible polymer.

In various embodiments it is therefore possible to realize an optical device for measuring the concentration (or other characteristic quantity) of a substance or liquid solution as a separate and independent component with respect to the body of a different functional device, which here is assumed to be a sensor of level, to be coupled preferably in correspondence with a through seat of the body of the latter. Alternatively, it is also possible to realize an optical measuring device having a body which defines a portion performing the functions of the housing and / or assembly part previously indicated with 12, provided with a through seat in which to house and / or fix a different version of the body of the level sensor or of a different device, or still provide a body of the optical device which defines an enclosure of the type indicated below with 14, in order to receive at least a part of the circuit support which is appointed to measure the level or of a different size (such as the portion of the support 15 hereinafter indicated with 15b).

In this way, an optical measuring device according to the invention can be integrated, for example, into level measuring devices and the like. A substantial advantage of this type of solution is that the materials that make up the main body of the level sensor and the body of the optical device according to the invention could be different: for example, for the body of the optical device which defines the site of positioning 30 a transparent material can be used, for example to obtain better optical characteristics, while a different material, even non-transparent, can be used for the body of the level sensor (or other device), for example to obtain better mechanical characteristics . In various embodiments, the body of the optical device according to the invention is made of thermoplastic material, in particular PSU, while the body of the different device is preferably made of a thermosetting material or resin.

Referring for example to Figures 72-73, 110a indicates the main body of a level sensor 110 having a level detection part 111, intended to face and / or extend at least partially inside a container, for example a tank 1. The body 110a then includes a housing and / or mounting part 112, configured to be hermetically coupled to the tank, for example in an opening similar to that indicated by 6 in Figure 1, possibly with a different increased diameter: in in this way, in the assembled condition, a part of the body 110a, and in particular its part 111, extends inside the tank, substantially vertically, with a bottom of the housing portion 112 which also faces towards the inside of the tank, in contact with the liquid substance. The housing and assembly part 112 is preferably provided with a relative closing lid 113, similar in shape to the lid 13, of suitable diameter.

Preferably the body 110a is internally hollow to house at least part of the level detection components, in particular the components of a capacitive level sensor, as well as at least part of the components of a device 10 according to the invention. In particular, the body 110a defines, in correspondence with the detection part 111, a hollow casing 114, of generally elongated shape; in the example shown, the casing 114 has a generally prismatic shape, particularly substantially parallelepiped. In preferred embodiments, the body 110a defines in a single body of plastic material the housing part 112 and the casing 114. However, an embodiment of the body 110a in distinct parts made integral and sealed, for example by means of reciprocal means, is not excluded. coupling, or by welding or overmoulding.

Again in Figure 72 it can be seen how the housing part 112 defines a cavity, indicated as a whole with H1, which together with the cover 113 defines a housing for part of the electrical and electronic detection components. In a preferred embodiment, at least part of said components is mounted on a circuit support 15 having a different shape with respect to the previously illustrated embodiments. In particular, in the support 15 of figure 72, a first portion 15a is identified, intended to be received in the housing part 112, and a second portion 15b intended to be received in the casing 114.

The portion 15a of the support 15 is mainly associated with the electronic detection and / or control components, which are preferably connected both to the level sensor 110 and to the optical sensor device 10 in accordance with the invention. The aforementioned components preferably includes both the components for the treatment and processing of signals relating to level detection, and the components for the processing and processing of signals relating to quality detection. The terminals 16 form, with a connector body 113a of the cover 113, an interface or connector for the external electrical connection of the unit formed by the level sensor 110 and the optical device 10, for example to a control unit of the on-board system 2 of a vehicle. At least part of the components used for level detection is associated with the portion 15b of the support 15. In various embodiments, such components include a series or array of electrodes, schematically represented by the block indicated with J, such as electrodes extending transversely to the axis of the portion 15b, substantially from the proximal end to the distal end of the sensing part 11. Preferably, the level detection is carried out by means of a measuring arrangement without moving parts, such as for example a float, particularly for reasons of reliability; for this purpose, in various embodiments, the level measurement arrangement is made according to the technique described in any of the international patent applications PCT / IB2015 / 054020, PCT / IB2015 / 057036 and PCT / IB2015 / 057043, in the name of the Applicant, whose teachings in this regard are incorporated herein by reference.

In the illustrated example, a single circuit support 15 is provided in which the parts 15a and 15b are defined, but in possible embodiment variants several circuit supports can be provided, connected to each other by suitable electrical interconnection means and possibly mechanical interconnection means, for example a circuit support corresponding to the portion 15a and a circuit support corresponding to the portion 15b, with electrical conductors or connectors for connecting electrically conductive tracks of one portion to electrically conductive tracks of the other portion, or a circuit support bearing part of the components relating only to the detection of quality (or other characteristic of the substance), connected to a circuit support bearing at least part of the components relating to the level detection.

In various embodiments, the housing and / or assembly part 112 of the body 110a includes a peripheral wall 120 and a structure or bottom wall 121, which define the cavity H1 suitable for housing electrical and / or electronic components. Preferably, the peripheral wall 120 - here substantially cylindrical in shape - has a flange 120a for fixing the body 110a in position. In the assembled condition of the device 10, at least a part of the structure or bottom wall 121 - and particularly of its external side - is intended to be in contact with the liquid solution contained in the tank. At the bottom wall 121 there is defined at least one opening or seat 122, which connects the cavity H1 to the internal cavity of the casing 114, which can house a detection part of a level sensor (such as part 15b of the circuit 15 bearing the electrodes J) or, in other embodiments, of a different sensor or electric heater device.

As said, the cover 113 includes or defines a generally hollow connector casing 113a, for housing the electrical terminals 16. The cover 13 is intended for fixing on the main body 110a, particularly on its housing and mounting part 112, so as to close - preferably sealed - the cavity H1. In various embodiments, the cover 113 defines for the purpose a flange 113b, for fixing the part 112 to a flange 120a. Preferably, in at least one of the bodies 110a and 113 there are provided means for fixing the level sensor (or other device) to the tank, such as perimeter holes, for example holes 120b in the flange 120a and holes 113d in one or more radial formations 113c of the flange 113b.

In various embodiments, the main body 110a has a seat or a through opening 121c in its bottom wall 121, in correspondence with which a device 10 according to the invention is intended to be mounted tightly.

The device 10 is visible in different views in Figures 74-75. The device 10 has a respective main body 10a formed at least in part with a material transparent to the working light or optical radiation of the optical sensor. The body 10a has a peripheral wall 20, preferably defining a flange portion 20a, and a bottom wall 21 intended to be exposed to the substance contained in the tank 1. Preferably, moreover, along the peripheral wall 20 a seat 20c is defined for an annular sealing element, indicated with 150 only in figure 76.

In various embodiments, in its upper part, particularly in correspondence with its peripheral wall, the hooking elements 20d rise from the body 10a, for hooking at the opening 121c of the body 110a. The hooking elements 20d can define a tight fastening in combination with the sealing element 150, or they can realize a temporary fastening during production phases, the final fastening and / or sealing being then realized in another way, for example by welding or bonding or resin bonding between the body 10a and the body 110a (for example a laser or vibration welding or by melting the material of at least one of the body 10a and the body 110a).

The positioning site 30, including the optical formation 31, on which an optical module 40, the site, the module and the relative connections being able to be made substantially according to any of the previously described and / or illustrated embodiments; the connection to the support 15 can be made by means of electric wires or an electric connector, optionally of the rapid or "snap in" type, or by means of suitably shaped terminals 50.

In embodiments of this type it is preferable that the separate spring (60, 601, 602) of the previous embodiments is replaced by a bridge element 603, which extends between opposite parts of the opening 121c, integral with or secured to the wall 121 of the body 110a. Referring for example to Figure 77, also element 603 therefore includes a central part 61 provided with a hole 61a having a profile congruent to the plan profile of the formation 51 and of the appendages 35. The two opposite arms extend from the central part 61 62.

As can be understood, the device 10 is obtained by preparing the body 10a, particularly by molding, to which the sealing element 150 is preferably associated. The module 40 is fitted onto its formation 31 and the device 10 is then mounted tightly in the relative seat 121c starting from the outer side of the bottom wall 121, so that the teeth 20d engage on the inner side of the same wall 121. The coupling between the bodies 10a and 110a could be of the elastic type following the interposition of the sealing element 150, which in this case allows an elastic assembly of the device 10 with respect to a possible bridge element 603 of the rigid type, such as a bridge element made in a single piece with the body 110a.

The positioning of the device 10 is carried out taking care that the formation 51 of the module 40 and the respective protruding parts of the appendages 35 of the formation 31 are engaged in the central hole 61a of the bridge element 603. In the assembled condition, as shown in figure 77, the arms 62 of the element 603 engage the seats 46a and 47a (figure 76) provided on the external side of the bodies 46 and 47 and provide for the elastically positioning and / or stressing of the bodies themselves in the relative abutment position: in this way the precise positioning of the emitter 42 and the photo-detectors 44a, 44b relative to the inclined surfaces of the formation 31. The connection to the circuit 15 is then made; for example through the electric wires 501, as shown in figure 78.

It should be noted that, in accordance with further possible embodiments of the invention, it is also possible to provide a body of the optical device, for example a body of the type previously indicated with 10a, and subsequently overprint a body of a different device on it. or sensor, for example a body of the type indicated previously with 110a, or vice versa overprinting the body of the optical group on the body of the other device or sensor. Of course, an embodiment of this type, i.e. with overmoulding of a further body (such as the body of a further sensor or of a component of the UDM type or of a heater device) on a body of the optical device, or vice versa, can be implemented in all the embodiments of the invention which are described and / or illustrated in the present application.

As can be understood, in various embodiments - such as that of Figures 72-78 - an optical sensor device according to the invention and a different sensor (such as a level sensor and possibly also at least one temperature sensor) and / or a different device or component have a common electrical connection connector, represented here by the connector 113a, 16. Likewise, the device object of the invention and at least one further device or component or a further sensing arrangement or a different sensor, such as an arrangement level and / or temperature detection devices, may share part of the same circuit arrangement, and in particular at least its electronic controller MP, which will therefore be configured to manage the operation of the plurality of different sensors and / or devices. Similarly, preferably, the same circuit - here represented by the circuit 15 - determines at least part of the connections of the optical sensor and / or an emitter and a receiver of the optical sensor and of the detection and / or control means of at least one further sensor, such as a level sensor and / or a temperature sensor.

According to possible embodiments, the site 30, and particularly its formation 31, can be provided with a diffraction grating on one of its optical surfaces, particularly the inclined surface 33a.

In these implementations, the operating principle of the optical sensor remains unchanged, always based on the variation of the critical angle as a function of the concentration of the liquid solution. The modification, which can be applied to all the embodiments described here, consists in inserting a diffraction grating on the optical surface 33a in correspondence with the emitter, that is - referring to figure 79 - in the area indicated with 107, preferably an area or sloped surface. However, the basic structure remains unchanged with respect to what has been described up to now.

The diffraction grating 107, in the presence of an incident monochromatic light beam, gives rise to a transmitted beam and to various diffracted beams, with a diffraction angle that depends on the ratio between the distance between the lines of the grating 107 and the wavelength of the incident light. With the same grating 107, the light with a larger wavelength is deflected at a larger angle than the incident direction. By means of the diffraction grating 107, the incident ray is then decomposed into various light rays called the order or mode of diffraction.

The diffraction grating 107 is obtained by obtaining on the optical surface 33a, i.e. on the side facing the emitter 42, an ordered alternation of recesses and / or reliefs, which give rise to a sort of battlements or a series of grooves, preferably parallel to each other , as schematized in figure 80 (at least some ridges and / or recesses could possibly extend also in different directions or be at least partially crossed). Naturally, the grid pitch, i.e. dimensions and distance between the recesses and / or reliefs, must be chosen according to what has just been explained above.

By breaking down the monochromatic ray emitted by the emitter, diffracted rays will be generated which will affect the liquid / solid interface surface - that is the external surface 211 of the wall 21 between the two parts 33, 34 of the formation 31 (figure 79) - at different angles , above and below the critical angle. The diffracted rays that strike with an angle greater than the critical angle on the interface surface 211 will be totally reflected, while those incident with a lower angle will always be partially reflected and partially refracted. As the concentration of the liquid solution varies, as explained above, the critical angle will change and consequently the intensity of the light rays on the two photo-detectors 44a, 44b. The electrical signal generated by the two photo-detectors will therefore change as a function of the concentration and by measuring the variation of the signals of the two photo-detectors it will be possible to measure the variation in concentration.

In embodiments of this type it is preferable that the emitter 42 is of the concentrated type, i.e. collimated, with a divergence of the emission limited to a few degrees, preferably less than 3 ° (in the embodiments that do not provide for the grating 107 not the emitter 42 must be of the collimated type). The spatial filter 43 is however preferably used to collimate the light emission generated more around the diffraction grating 107. If the emitter 42 is of the monochromatic type, the diffracted rays will always be of the monochromatic type and therefore also the photo-detectors 44a, 44b must be sensitive to the same monochromatic rays of the source (i.e. with a specific wavelength) .

On the other hand, if the emitter 42 is of the polychromatic type, the diffraction grating 107 also allows the light rays to be separated in terms of wavelength (i.e. in the different colors): considering the operating principle, the two photo-detectors 44a, 44b will receive rays with different wavelengths and therefore they must be sensitive to light rays of different wavelengths. Alternatively, it is possible to use several diffraction gratings 107 with different pitches, designed in such a way as to direct the light always on the two photo-detectors, with several emitters 42 at different wavelengths: in these embodiments, the emitters 42 are switched on in different times and the resulting signals always acquired with the same photo-detectors.

However, it is preferable to use a monochromatic 42 light source, to avoid introducing the variation of the refractive index (and therefore of the critical angle) also as a function of the wavelength and not only of the concentration of the liquid solution.

As regards the diffraction grating 107, various shapes are obviously possible, in order to obtain the desired effect, even different from those exemplified. The profiles of the grating 107 can be obtained by mechanical engraving or with holographic techniques or, preferably, with micro-processing techniques borrowed from microelectronics, or with micro-molding techniques. In particular, the solution in which the diffraction grating 107 is molded in one piece together with the formation 31 (i.e. the body 10a or the body 101) is preferable: in this case the mold used can be of the modular type, i.e. with a suitably insert superficially structured micro, in correspondence with the point where the lattice 107 is to be defined.

In various embodiments, the device according to the invention is equipped with a quality optical sensor or other characteristics of the substance whose operating principle is based on internal reflection, or on the use of an optical waveguide. Embodiments of this type are described with reference to figures 81-88 and 89-97, which use the same reference numbers of the previous figures, to indicate elements that are technically equivalent to those already described above.

As is known, considering a light source that illuminates the entrance of an optical fiber, the discontinuity of the refractive index between the materials of the core and the cladding of the fiber traps the light radiation as long as it maintains a fairly grazing angle and inserted inside the acceptance cone. In practice, in order to function well according to the total reflection, the fiber must not make too sharp bends. The principle of total internal reflection can be exploited for a measure of characteristics or concentration always considering the difference in the refractive index between two media - namely the plastic material of the body 10a or 101 and the substance or liquid solution in contact with this body. - and the variation of this index as a function of the concentration of the substance or solution.

Referring initially to Figure 81, in various embodiments, a positioning site 301 is defined in correspondence with the internal side of the wall 21 of the body 10a, differently shaped with respect to the previous embodiments, which includes a seat 311 for an optical module 401, also having a different structure with respect to the embodiments described up to now. In the illustrated example, and as clearly visible in figure 82, the support structure of the module 401 comprises a substantially plate-like body 411, to whose lower side an emitter 42 and a receiver 44 are associated, here consisting of a single photo-detector . The body 411 can advantageously be made of a printed circuit support, PCB type, on which tracks of electrically conductive material 481, 491 are provided for the electrical connection of the electronic components 42 and 44. The support 411 has respective connection elements 503, connected to the aforementioned tracks, for example in the form of welding pads and / or metallized through holes, for the electrical connection of the module 401. Also in this case, preferably, the emitter 42 is associated with a relative spatial filter 43 of the type previously described. In accordance with possible alternative embodiments, not shown, the support 411 can also comprise a body formed with an electrically insulating material, for example a plastic material, overmolded with electrical connection elements of electrically conductive material, which perform the functions of the tracks 481, 491 and connecting elements 503, thus using a technique similar to described in relation to previous embodiments.

In the example, the support 411 has a substantially quadrangular shape, and the seat 311 defined on the internal side of the wall 21 is correspondingly shaped, to receive inside at least part of the support 411, with the emitter 42 and the receiver 44 facing the wall 21. Other shapes are obviously possible for the seat 311 and the support 411. Preferably, the wall 21 also defines support stops for the support 411 within the seat 311, one of these stops being indicated with 371 in figure 81. From on the other side, in correspondence with the external side of the wall 21, the body 10a defines or comprises an optical guide, adapted to diffuse the light or optical radiation emitted by the emitter 42 up to the receiver 44. This guide, indicated with 312 in figure 83 , preferably has a generally U-shaped configuration, the two ends of which are in correspondence with the area which, on the internal side of the wall 21, is circumscribed by the seat 311. The optical guide 312 it can be integrated in the body 10a, for example molded in a single piece, particularly in a material permeable to an optical or light emission; alternatively, the optical guide 312 can be mounted in the body 10a, for example associated with its own body similar to the body 10a of figures 72-78, preferably made of a plastic material permeable to light or optical radiation, molded separately and then mounted on the body 10a, or again overmolded on the body 10a, with the latter being formed with a material of a different type, such as a plastic material that is not permeable to light or optical radiation.

The optical guide 312 is preferably massive, i.e. solid, and is made with the material suitable for the diffusion of optical radiation, as previously explained, to substantially fulfill the functions of an optical fiber core: as will be seen, the functions of the this fiber is instead fulfilled by the liquid solution contained in the tank, in which the guide 312 is immersed.

The module 401 is preferably mounted by interlocking in the relative seat 311, as shown in figure 84, in order to have a precise assembly of the emitter 42 and receiver 44 components with respect to the two ends of the guide 312. In preferred embodiments, in order to make it more rigid and sturdy assembly of the module 401, it is possible to provide for a resin coating and / or gluing of the same in its seat 311.

Also in embodiments of this type, the circuit 15 is inserted into its seats 22, as schematized in figure 84, with the circuit itself remaining within the cavity of the body 10a. Subsequently, the electrical connection of the module 401 can be carried out by means of electrical wires 501 or other terminals, connected to the holes or pads 53 or the like provided in the circuit 15, as shown in figure 85.

As can be seen in figure 86, in the mounted configuration of the module 401, the emitter 42 and the receiver 44 each face a respective end of the optical guide 312 which, in the mounted condition of the device 1, is immersed in the liquid solution (it should be remembered that , in the configuration of actual use, the device 10 is preferably in an inverted position by 180 ° with respect to what is illustrated in the figure). As indicated, a spatial filter 43 is preferably associated with the emitter 42, to improve the concentration of the emitted light beam and make it re-enter the acceptance cone of the guide 311.

In operation, the emitter 42 emits light in front of the first end of the guide 312, which as mentioned is preferably integrated into the body 10a, or formed in a single piece with it, and is immersed in the solution whose concentration is to be measured, which fulfills cloak functions. In front of the opposite end of the guide 312 is the receiver 44, designed to capture the light beam emitted by the emitter 42 and propagated inside the plastic body of the guide by exploiting the internal reflection.

Figures 87 and 88 exemplify two situations with a liquid solution at two different concentrations. In the case of figure 87 the solution has a first concentration "Conc 1", such that the critical angle is less than the angle of incidence of the ray R emitted by the emitter 42. The ray R is therefore totally reflected, arriving at the receiver 44 with some intensity. Consequently, a certain value of the output signal from receiver 44 is assigned to the concentration value "Conc 1". Figure 88 instead highlights the case in which the liquid solution has a concentration "Conc 2" which is greater than Conc 1. In this case the critical angle increases and the ray R incident on the interface surface between the material of the guide 312 and the liquid, with the same angle, will be partially reflected and partially refracted, as exemplified in figure 88. Various reflections will follow and refractions whenever the reflected ray in the previous step will affect the interface surface. Consequently, the ray R will reach the receiver 44 with a certain attenuation, caused by the partial reflection / refraction, that is with a lower intensity than in the previous case with concentration equal to "Conc 1" in figure 87. The signal emitted at the receiver output 44 will therefore be different from the previous case, allowing to discriminate the concentration value. Considering the transimpendance, the gain and the response of the receiver 44, there will be a signal A which will vary with the intensity P incident on the receiver, and consequently with the concentration of the fluid, similar to what has already been explained above:

A = ka * P * response * transimpedance

The intensity P incident on the receiver 44 will be given by the combination of all the rays emitted by the emitter 42 inside the emission cone, totally and partially reflected inside the guide 312. The rays with partial reflection will therefore have an intensity decreasing with each reflection: if the intensity P is not high enough, these rays could also be canceled and not reach the receiver 44.

As mentioned, the measurement is based on an intensity detection: the receiver 44 changes its output signal based on the variation of the incident light intensity, a function in turn of the concentration of the liquid solution.

With construction of the type indicated, the quality measurement system is sensitive to the operating variation of the emitter 42 and to the variation of the characteristics of the plastic material that makes up the wall 21 and the guide 312, mainly caused by aging and temperature variations. These factors could alter the light intensity of the emitted ray (aging of the source) or the optical properties of the plastic material (refractive index and consequently critical angle) causing measurement errors.

Therefore, in accordance with particularly advantageous embodiments, an additional or auxiliary emitter and receiver are provided, preferably facing each other, with at least one reference optical element or waveguide interposed not immersed in the fluid to be detected; this optical reference guide is preferably located in the cavity H and / or in correspondence with the internal side of the wall 21. Preferably the aforementioned optical reference element or guide is formed with the same material as the optical detection guide 312 and / or the wall 21 and / or body 10a (or 101). In the case exemplified in figure 85, said additional emitter and receiver - indicated with 421 and 441, respectively - are arranged at the two opposite ends of a formation 372, which is preferably defined in a space comprised between the seat 311 and the seats 22, with this formation which therefore forms the aforementioned optical reference element or guide. However, this optical reference guide can be configured as an independent element, mounted between emitter 421 and receiver 441, or even be defined by one of the walls of the seat 311, for example the rear wall closest to the seats 22.

In the example illustrated, the emitter 421 and the receiver 441 are mounted on the circuit support 15 (see figure 84) in an area such that, following the complete insertion of the circuit itself in the relative seats 22, they face each other. at the two ends of the formation 372.

The ray emitted by the emitter 421 and consequently received by the receiver 441 is not involved by any refractions / reflections with the liquid solution, as this ray remains mainly confined within the body 10a, and precisely of its formation 372. The components electronic components 421 and 441 are of the same family, in terms of characteristics, of the electronic components 42 and 44 used for concentration measurement: in this way, through the aforementioned additional components, it is possible to have a reference on the light intensity emitted to be used for a normalized measurement and compensate for the variations in intensity produced by aging and / or environmental variations of the material of the body 10a and / or of the optical reference guide 372 and / or of the optical detection guide 312. This reference is constituted by the signal emitted by the receiver 441, which will be used by the control electronics to perform the necessary compensation of the eme signal xed from the receiver 44.

It should be noted that, similarly to what is described with reference to Figures 72-78, the module 401, the seat 311 and the light guide 312, and possibly also the optical reference guide 372 and / or the relative emitter 421 and receiver 441, could belong to a distinct group, which can be positioned hermetically in correspondence with a relative through opening of a different device or component, such as a level sensor or a different sensor or a UDM component or a heating device.

In various embodiments, the electronic components 42 and 44 used for the measurement and the similar components 421 and 441 used to correct this measurement can also be integrated in the same optical module. Variations of this type of embodiment are described with reference to Figures 89-97, which use the same reference numbers of the previous figures, to indicate elements technically equivalent to those already described.

Referring initially to Figures 89-90, 402 indicates an optical module of the type indicated, i.e. comprising components 42, 44 and 421, 441, which is intended to be mounted at a positioning site 302 defined on wall 21 of body 10a. The site 302 includes a formation 313, which includes at least two generally parallel mounted parts or appendages 35, functionally similar to the appendages 35 of the embodiments described above. The formation 313 is located within a seat 314 defined in the back wall 21; in the example, this seat has a substantially C-shaped shape and is defined by a major wall and two side walls which protrude from the inner side of the wall 21. From the wall 21 also protrudes a further wall 315, here generally parallel to the major wall of the seat 314, which in the mounted condition of the module 402 is intended to be interposed between the auxiliary emitter and receiver, as explained below. The module 402 is intended to be secured on the formation 313 by means of a locking and / or positioning element generally shaped like a ring 604, provided with a central finned hole. In various embodiments, the module 402 is electrically connected to the circuit 15 in a manner similar to those described with reference to Figures 2-26, or by using elastically flexible terminals of the module itself, or connected with wires or in other ways previously described.

A possible embodiment of the module 402 and its structure 412 is illustrated in Figures 91-93. The supporting structure 412 of the module 402 essentially consists of a body in plastic material with a substantially C-shaped shape, that is, comprising a central upper wall 453 and two side walls 463 and 473, generally orthogonal to the central wall, at its two ends, or possibly of the walls 463 and 473 inclined with respect to the central wall 453. This body is overmolded with connection terminals 50, functionally similar to the terminals 50 of Figures 2-26, preferably at least partly elastically flexible, intended for connection to the circuit 15. The body of the structure 412 is also overmolded to conductors 482 and 492 - which are partly accessible at the underside of wall 453 - for the electrical connection of the emitter 42 and receiver 44, respectively, as well as to terminals which are partly accessible at the external side of walls 463 and 473, for the connection of the emitter 421 and the receiver and 441 auxiliaries (in figure 91, one of the conductors relating to the emitter 421 is indicated with 484, the conductors for connecting the receiver 441 having a substantially similar arrangement).

In correspondence with the upper face of the central wall 453 a formation 51 with the relative through openings 51a is provided, while in correspondence with the lower face of the same wall a formation 52 with the relative wall 52a is provided, as in various embodiments previously described . The auxiliary electronic components 421 and 441 are mounted on the external side of the walls 463 and 473, which for this purpose are provided with through holes 463a and 473a, the hole 463a provided for the emitter 411 essentially performing the functions of a spatial filter. The electronic components 42 and 44 are mounted on the internal side of the wall 453. The emitter 42 is preferably associated with a relative spatial filter, for example of the type previously indicated with 43.

Preferably, moreover, the upper face of the central wall 453 has two positioning protrusions 511 for the locking element 604, the profile of which defines recesses susceptible to engagement with the aforementioned protrusions 511.

As can be seen, with respect to the version of figures 81-88, the auxiliary emitter 421 and receiver 441, provided to compensate for the aging of the emitter 42 and of the plastic material of the body 10a, are mounted on the module 402 also bearing the main detection emitter 42 and receiver 44.

In the exemplified case, the module 402 is connected to the circuit 15, preferably by means of the flexible terminals 50, although other connections, even of the rigid type, can be used. The locking element 604 can be preassembled on the upper formation 51 of the module 402, also utilizing the relative positioning protrusions 511. The circuit is then inserted into the seats 22, as shown schematically in figure 94, until the module 402 reaches the support on the seat 314, as schematized in Figures 95 and 96. In this phase the two appendages 35 of the formation 313 insert into the through openings 51a and the wall 52a of the lower formation 52 of the module inserts itself between the two appendages (see for reference the figure 96), with some fins of the central hole of the locking element 604 which make the necessary grip on the external sides of the appendages 35.

In the assembled condition, as can also be seen in Figure 97, between the emitter 421 and the receiver 441 the wall 315 (or other suitably shaped wall) is interposed: the beam generated by the emitter 421 reaches the receiver 441 crossing the wall 315, determining a reference signal.

In this way, similar to what has already been described above, it is possible to have a reference to compensate for any variations in light intensity due to aging of the main emitter 42: as mentioned, in fact, the emitters 42 and 421 are of the same family. Moreover, thanks to the presence of the wall 315, the ray incident on the receiver 441 is a function of the refraction introduced by the plastic material of the body 10a: in this way, similarly as described with reference to figures 81-89, the variation of the refractive index due as the plastic material ages, it involves a variation in the intensity of the refracted light beam and therefore a variation in the light intensity on the receiver 441, or in the signal emitted by the latter. Therefore, by considering the signal of the auxiliary receiver 441 as a reference, it is possible to compensate for the variation in the properties of the material and / or alterations due to other environmental factors or conditions of use.

Figure 98 shows an example of a possible electrical diagram of the module 402, for its connection to a relative interface circuit, here represented by the circuit 15 of the level sensor device 10. As can be seen, the terminals 50 preferably allow to have as signals of input and output a power supply level Vcc of the emitter 42 and of the emitter 421, a ground GND and two voltage signals A and C relating to the two photo-detectors 44 and 441. These signals A and C are sent to the circuit 15 for numerical processing on the MP controller (as also schematized in Figure 99) and / or sent to an external circuit through the electrical connector 13a, 16 (or 113a, 16).

On the other hand, Figure 99 illustrates an operating block diagram of the optical quality sensor including module 402. In this figure, Vcc indicates the low voltage power supply of emitters 42 and 421, block OG is intended to represent the geometry given by the guide 311 and the corresponding wall part 21, and the OR block is intended to represent the part 315 of the body 10a interposed with the emitter 421 and the receiver 441. As can be seen, the voltage signals A and C in output from the receivers 44 and 441 are treated by a conditioning circuit CC and the conditioned signals A1 and C1 reach the relative inputs of the microprocessor MP which - by correcting the signal A1 as a function of the signal C1 - generates the signal S representing the concentration value of the solution or of another characteristic or type of the substance. Also in this case the components CC and MP are preferably located on the circuit support 15, with the microcontroller MP managing both the level detection and the quality detection of the liquid solution. The block diagram of figure 99 is of course also valid in relation to the embodiments described with reference to figures 81-88.

The general operation of the optical quality sensor of Figures 89-99 is also similar to that described with reference to Figures 81-88, particularly as regards the use of the emitter 41 and of the receiver 44 in combination with the light guide 312 ( see in particular the part of the description relating to figures 87-88).

Obviously, each of the site 302, the formation 313, the seat 314 and the wall 315 could have a different shape from the one exemplified, without prejudice to their functions, and that instead of the flexible terminals 50 electric wires of the type indicated above could be used. with indicated with 501.

In various embodiments, the optical sensor that equips the device 10 according to the invention at least partially bases its operation on the laws of optical refraction, and in particular on the refraction of a light ray in the passage from a solid to a fluid (two means with different refractive indices) and on the variation of the refractive index with the concentration of the fluid. As known from physics and from Snell's equation, keeping the angle of incidence of the incident ray fixed, the variation of the refractive index of the fluid - representative of its concentration, as already explained above - involves a variation of the angle of the ray refracted through the fluid. By appropriately arranging a light radiation receiver element, it is therefore possible to detect the position of incidence of the refracted ray and thus measure the concentration and / or characteristics of the fluid.

Embodiments of this type are described with reference to figures 100-111, which use the same reference numbers as the previous figures, to indicate elements that are technically equivalent to those already described.

Referring initially to Figure 100, in embodiments of this type there is a positioning site 303 including a formation 210 which rises from the wall 21 towards the interior of the cavity H of the body 10a. The formation 210 comprises a shaped wall which, preferably but not necessarily, extends through the cavity H and has positioning elements at the top for an optical module 403. In the example, this module 403 is intended to rest on the upper surface of the formation 210, which preferably defines at least one upper appendage 210a and, very preferably, side abutments or abutments 210b for the module 403, as shown in Figures 105 and 106.

In embodiments of this type, the use of a shaped optical insert is provided for the propagation of a light beam, indicated as a whole with 220, formed at least in part in a material that is transparent or permeable to the optical working radiation of the sensor, for example the same material as the wall 21. The optical insert 220 is intended to be housed in a relative seat, indicated with 230, essentially consisting of a portion of the bottom wall 21, which is shaped so as to define a protruding cavity with respect to the plane of the same wall, as clearly visible in figure 101. As can be seen in this figure 101, the portion defining the seat 230, which is intended to be immersed in the liquid solution, includes two external surfaces 230a, 230b angled to each other. In the example, the two surfaces 230a and 230b form an angle greater than 90 ° to each other.

The insert 220 is represented in different views in figures 102 and 103, preferably molded and / or made of a plastic material. The body of the insert 220 has a main wall 221, preferably flat and provided with a through hole 221a intended for coupling with the appendix 210a of the formation 210. Preferably an appendix 221b protrudes from the upper side of the wall 221, for the positioning of the optical module 403.

From the lower side of the wall 221 protrude two elements for the transmission of light 222 and 223, each of which has, at the distal end, a surface or inclined plane 222a and 223a, preferably inclined substantially at 45 °. Preferably, moreover, the body of the insert 220 also defines two housings or seats 222b and 223b, which open at the upper side of the wall 221, each at a respective transmissive element 222 and 223. The body of the insert is preferably formed in a single piece, including the transmissive elements 222 and 223. As will be seen, the seats 222b and 223b are intended to house at least partially an emitter and a receiver of the optical module 403. Preferably, the transmissive element 223 has a elongated cross section, for example substantially rectangular, since the relative inclined plane 223a is intended to receive an incident light ray whose position can vary - in the longitudinal direction of the plane 223a - as a function of the concentration of the liquid solution. The transmissive element 222 in the example has a circular section. The seat 230 (figures 100-101) is designed to receive at least part of the transmission elements 222 and 223 inside and is therefore shaped accordingly and / or with at least partially complementary shape, preferably with at least some internal walls of the seat 230 facing each other. or coupled to at least some surfaces of the transmissive elements 222 and 223.

Referring to Figure 104, the optical module 403 has a structure 413 which comprises a substantially plate-like support body, preferably consisting of a printed circuit or PCB support, which has two through openings 413a and 413b, respectively for the appendix 210a of formation 210 and appendix 221b of insert 220.

At least one emitter 422 and at least one receiver 442 of optical radiation, preferably visible radiation, are associated with the lower side of the structure 413. The emitter 422 can be, for example, an emitter diode. In preferred embodiments, the receiver 442 is a receiver of the C-Mos array type, comprising a linear series or a matrix (array) of independent pixels, each consisting of a photodetector. The structure 413 includes suitable elements for the electrical connection of the components 422 and 442, not illustrated for reasons of clarity, comprising for example tracks made of electrically conductive material and metallized holes for the leads of the aforementioned components. In accordance with possible alternative embodiments, not shown, the structure 413 can also comprise a body formed with an electrically insulating material, for example a plastic material, overmolded with electrical connection elements of electrically conductive material, which perform the functions of the aforementioned tracks and holes, or using a technique similar to described in relation to previous embodiments.

In preferred embodiments, the electrical connection between the module 403 and the circuit 15 of the device is made by means of a flat cable indicated with 504 for example in figures 100-101, in which case the circuit 15 it will preferably be equipped with a connector or conductive tracks and / or pads for connection. Obviously it is also possible to make a connection by means of flexible terminals or separate electric wires or with other connections, according to what has already been described previously. Naturally, a ribbon cable can also be used for connecting the optical modules of various embodiments described above.

For assembly purposes, the optical insert 220 is mounted on the body 10a, as shown schematically in Figure 105, particularly in such a way that the lower side of its wall 221 rests on the upper surface of the formation 230. In this phase, takes care that the hole 221a of the insert 220 is fitted on the appendix 210a of the formation 210. In the assembled condition, as shown in figure 106, the upper stops of the formation 210 contribute to the correct positioning of the insert 220. In this condition, moreover , the elements 222 and 223 of the insert are inserted in the relative seat 230, particularly with the inclined plane 222a of the element 222 in the opposite position to the external surface 230b of the seat 230 (see reference figures 101 and 109) and the inclined plane 223a of the element 223 in the opposite position to the external surface 230a of the seat 230 (see for reference Figures 101 and 111).

Subsequently, the circuit 15 with the module 403 pre-assembled is inserted into the cavity of the body 10a, until the module itself rests on the upper side of the insert 220. For positioning purposes, the holes 413a and 413b of the structure of the optical module couple with the appendix 210a of the formation 210 and the appendix 221b of the insert 220, respectively, as shown in figure 107. In this condition, moreover, the emitter 422 and the receiver 442 are positioned and / or at least partially housed inside the relative seats 122b and 123b of the insert 120 (see reference figures 109 and 111).

At this point, the module is fixed in position by means of a fastening ring substantially of the type already indicated with 604, whose finned hole engages with interference on the appendix 210a. Ring 604 preferably also operates as a spring, allowing you to position the module 403 and the optical insert 220 and / or to recover any mounting tolerances. The cover 13 is then fixed on the body 10a, taking care that the circuit is coupled with the respective seats 13f (figure 101) of the cover itself.

As can be understood, at least the appendix 210a and the hole 221a provide means for positioning and centering the insert 220 relative to the formation 210, in combination with the possible stops 210b, while the appendix 210a itself and the appendix 221b of the insert 220 , with the holes 413a and 413b they provide means for positioning and centering the module 403 with respect to the formation 210 and the insert 220.

The insert 220 is intended to propagate the light beam generated by the emitter 422 up to the receiver 442 also through the body 10a, particularly through the walls 230a and 230b of the relative seat 230, and also through the liquid substance in which these walls are immersed. . The optical surfaces 222a and 223a of the insert are therefore designed to reflect the light beam correctly, also considering the air - plastic material interface. Similarly, the seat 230, and particularly its external surfaces 230a and 230b are designed for the purpose, to refract the optical or light beam at the plastic material - liquid solution interface.

The operation of the optical sensor is exemplified in Figures 109-111. Referring initially to Figure 109, the light ray R is emitted by the emitter 422 inside the insert 220, particularly inside its element 222, until it affects its optical surface 222a inclined by 45 °, which represents a interface between solid and air. For this purpose, the 422 emitter is preferably of the collimated type, to obtain a highly concentrated emission in the direction of interest.

The optical surface 222a is preferably designed and inclined to determine a total reflection at the interface between solid and air, with an output ray R1 at 90 ° with respect to the incident ray R. The interface surfaces between the element 222 and the relative part of the seat 230 are parallel and orthogonal to the incident ray R1, suitably finished at the surface level. The ray R1 propagates without changing direction, neglecting the small refraction that is generated by the reduced distance between insert 220 and seat 230.

Referring now to Figure 110, the ray R1 then affects the optical interface surface between the seat 230 and the liquid solution, this surface being represented by the outer surface 230b of the seat 230. The optical surface 230b is designed and inclined in such a way to where the ray R1 is refracted in the ray R2 inside the liquid, towards the other optical interface surface between the liquid and the seat 230, represented by the external surface 230a of the seat 230. Arriving at the second interface surface 230a, the ray Incident R2, due to the effect of refraction, is transformed into the ray R3 through the relative wall of the seat 230.

Considering also figure 111, the radius R3 passes from the inside of the seat 230 to the insert 220, and particularly to its element 223. The two interface surfaces plastic material (seat 230) - air and air - plastic material (element 223) they are parallel and orthogonal to the incident ray R3, so the ray does not undergo deviations, always neglecting the reduced distance in the air. The ray R3 affects the optical surface 223a inclined at 45 ° of the element 123, transforming itself into the ray R4 which is totally reflected towards the receiver 44a.

The ray R4 will affect the linear series or the matrix of the receiver 442 and will illuminate a determined pixel: in this way, a certain illuminated pixel will be associated with a given concentration "Conc 1" of the liquid solution, and therefore a signal generated by the receiver 442. If the R4 ray illuminates several neighboring pixels, it will be possible to process the signal to define a relative pixel or midpoint; alternatively, a different luminous intensity associated with each pixel could be detected, considering the highest pixel value as corresponding to the central point of the optical beam.

In case of a different "Conc 2" concentration of the liquid solution, the refractive index of the solution itself will change: thus keeping fixed the angle of incidence of the ray R1 at the interface surface, the angle of the ray R2 and consequently that of the radius R3 referred to in the case of the Conc 1 concentration will be modified in the case of the Conc 2 concentration, as shown in Figure 110 by the rays R2 'and R3'. Similarly to the case represented in figure 111, the ray R3 'will transform into another ray, similar to the ray R4, which will affect orthogonally on the receiver 442, but in a different point with respect to the ray R4, and consequently will illuminate a pixel different from the previous one ( the previous pixel illuminated with the Conc 1 concentration will instead be off). If the R4 ray illuminates several neighboring pixels, it will be possible to detect the various pixels and / or the relative signal intensity and calculate the relative pixel or midpoint. The variation of illumination within the series or matrix of pixels allows to identify the precise position of the ray incident on the receiver 442: in this way, it will be possible to associate a given value representative of the concentration to each variation of illumination on the pixels of the series or matrix. of the liquid solution.

From the above description the characteristics of the present invention are clear, as well as its advantages. It is clear that numerous variants are possible for the person skilled in the art to the optical sensor device described as an example, without thereby departing from the scope of the invention as defined by the following claims.

The presence of an auxiliary or reference arrangement, aimed at detecting at least one characteristic of a plastic material of the device body, for example variable following aging or conditions of use, must be understood as autonomously inventive, i.e. not necessarily linked to the presence of a main optical sensing arrangement, such as those including emitters 42, 422 and receivers 44, 442, or linked to the presence of a temperature sensing arrangement and / or a level sensing arrangement.

Such an auxiliary or reference arrangement of the characteristics of the material of a body of the device 10 can be of the optical type, for example of the type previously exemplified with reference to the emitters 421 and to the receivers 441 (Figures 84-89 and Figures 90-99) , or of another type suitable for the purpose, such as an arrangement which detects changes in the capacitance and / or electrical impedance or in the conductivity and / or thermal resistance of the material of a body (such as the body 10a).

As explained, the detections allowed by the aforementioned auxiliary arrangement provide information relating to the state of a material of the body of the device, in particular of a material which is transparent or permeable to optical radiation. Information of this type is useful for the purposes of compensating for measurements made through other sensors of the device according to an autonomously inventive aspect, such as level sensors and / or temperature sensors, when the relative measurements are carried out indirectly, i.e. in the presence of a wall (such as the wall 20 or 21 of the body 10a or the wall of the casing 114 of the body 110a) interposed between the detection means (such as the temperature sensor 19a or the electrodes J) and the fluid (the substance or the air environment) subject to detection.

It will be appreciated, for example, that the aging of the material of this interposed wall and / or the thermal stresses suffered by such material can determine a variation of the thermal conductivity characteristics of the material in question, with consequent negative influences on the accuracy of the temperature detection. . For this purpose, a reference arrangement of a thermal type could be provided, for example comprising at least one electric heater and a temperature sensor, associated with different points of the same reference wall.

Aging and / or thermal stress and / or alterations of the material of this interposed wall can determine a change in the electrical insulation and / or dielectric and / or electrical impedance characteristics of the material in question, with consequent negative influences on the accuracy of the detection if operated for example by means of capacitive and / or level sensor means with electrodes isolated from the fluid to be detected by means of a wall (such as the wall 114 and / or 120 of the body 110a). For this purpose, for example, a reference arrangement could be provided for detecting at least one capacitance and / or an impedance and / or an electrical resistance, comprising at least two electrical conductors or electrodes associated with different points of the same reference wall.

For applications of this type, the control electronics of the sensor device is suitably prepared to compensate for the measurements made based on information acquired through the auxiliary arrangement and therefore representative of any changes in the characteristics of the material in question. For this purpose, for example, related information can be encoded in memory means of the control electronics, for example in tabular form and based on empirical investigations, aimed at expressing the correlation between the reference property of the plastic material considered (such as an optical property, in particular its refractive index) and / or its other properties that influence a measurement to which the sensor device is intended (such as conductivity or electrical impedance and / or conductivity or thermal resistance properties). This information will be used by the control electronics, particularly by an electronic controller, to make the necessary compensations during the aforementioned measurement, for example during the temperature and / or level detection phase.

Obviously, the auxiliary or reference arrangement can be provided in any suitable position of the body of the sensor device which mounts it; in the case of an optical reference arrangement of the type described, a part formed with the same plastic material whose characteristics are to be monitored is preferably interposed between the relative emitter and receiver.

As previously indicated, the methods for producing the support structure and electrical connection of an optical module provided in accordance with the invention can be different and include, for example, the overmoulding or coupling of one or more bodies of the structure onto a a flexible circuit holder.

Figures 112-116 illustrate an example of a possible embodiment of an optical module, substantially of the type illustrated in Figures 37-38, based on overmoulding. In these figures the same reference numbers of the previous figures are used, to indicate elements that are technically equivalent to those already described above. In Figure 112, 300 indicates as a whole a flexible circuit or PCB support, which integrates electrical connection elements and, preferably also connection terminals. For this purpose, the support 300 comprises an insulating substrate 301 substantially foil or film, for example formed with at least one polymer, such as a polyamide, or Kapton®, or liquid crystal polymers (LCP), or a polyethylene (PE), such as a polyethylene naphthalate (PEN) or a polyethylene terephthalate (PET). The substrate 301 is provided with electrically conductive tracks, for example made of metal or a metal alloy or a polymer admixed with electrically conductive charges, which form the conductors 48 and 49 and preferably also the terminals 50.

A central part 3001 and two side parts 3002, 3003 are identified in the circuit support 300. The ends of the conductive tracks 48, 49 intended for connection to the emitter are located in correspondence with the distal end portions of the side parts 3002 and 3003. and the optical receiver, said ends of the tracks being preferably in the form of pads, not indicated. Preferably, the opposite ends of the tracks 48, 49 are instead located in correspondence with the central part 3001 of the support 300, particularly near one of its edges, to form the terminals 50; in the example, these terminals are made from pads having a central opening coaxial with corresponding through holes provided in the substrate 301.

In cases where the optical module must be provided with a positioning opening similar to that indicated with 45a in figures 37-37, the substrate 301 has a corresponding through opening 300a; in other embodiments, in which the aforementioned positioning opening is not necessary, the opening 300a can be omitted. In preferred embodiments, the substrate 301 of the circuit support 300 can in any case have one or more passages, some indicated with 300b and 300c, through which part of the insulating material of support and / or positioning bodies is intended to penetrate and consolidate. which, as will be seen, are overmolded to the circuit support 300. Preferably, at least one opening 300b is provided in each distal end region of the side parts 3002, 3003 of the support 300, as well as two openings 300c at the central part 3001 , also necessary for the creation of suitable openings in the central body of the support structure and electrical connection.

In various embodiments, one or more bodies intended to perform the functions of the bodies previously indicated with 45, 46 and 47 are overmolded on the circuit support 300. Figures 113 and 114 exemplify the case of a support and / or connection structure electric 414 which includes the three aforementioned bodies 45, 46 and 47, which are precisely overmolded in respective regions of the support 300, and in particular in correspondence with the central part 3001 and in the distal end regions of the lateral parts 3002, 3003. purpose, the support 300 as visible in Figure 112 is placed in a suitable mold, having the impressions necessary for defining the profiles of the bodies 45-47 (for example a mold substantially similar to that of Figure 15, with suitable impressions), in which the electrically insulating material necessary for the formation of the bodies is then injected, for example a polymer or a thermoplastic material. The aforesaid bodies can then be molded in such a way as to present the elements already described previously: for example, in correspondence with the central part 3001, the stop projections 45b as well as the upper 51 and lower formations 52 can be defined, with the relative through openings 51a, while the seats 46a, 47a and the appendages 46b and 47b can be defined in correspondence with the lateral parts 3002, 3003. During molding, the presence of the passages 300b, 300c of the substrate 3001 (Figure 112) allows the necessary flow of the injected material also towards the face of the support 300 opposite the injection point of the material and / or allows - after the solidification of the material - to ensure a solid fixing of the bodies themselves on the support 300; in various embodiments, such as the one shown, the passages 300c are also necessary for the purpose of defining the through openings 51a. Preferably, in various embodiments, for the purpose of fixing at least one of the bodies 45, 46, 47 to the support 300, molded material is provided in the passages 300b, 300c and on at least a portion of both faces of the support 300, and / or of the printed material along at least part of the edges of the support 300 and on at least a portion of both faces of the support 300.

Preferably, the lateral bodies 44 and 47 are overmolded on the support 300 so as to present, in correspondence with the relative lower faces, at least one passage, indicated with 46e and 47e in Figure 114, in order to leave exposed corresponding regions of the support 300 necessary for positioning and to the electrical connection of the emitter and receiver of the optical module. In the case of terminals 50 of the type exemplified here, it is also preferable that the lower face of the body 45 is also molded in such a way as to define passages which leave the terminals themselves at least partially exposed, as clearly visible in figure 114, for example to facilitate subsequent welding operations of the wires or electrical connectors of the optical module.

After being extracted from the mold, the structure 414 therefore appears as shown in figures 113 and 114, and the emitter 42 and the receiver 44a, 44b can be mounted on it, as shown in figure 115, connected to the respective conductive tracks 48 and 49, respectively, to obtain optical module, indicated as a whole with 404.

The module 404 can therefore be mounted in correspondence with the relative optical site of the body of the device, substantially in the manner described above: in this type of embodiment, between the lateral bodies 46, 47 and the central body 45, respective portions of the support remain exposed. 300, indicated with 301a only in Figure 116, which is on the whole flexible and / or deformable. By exploiting the flexibility and / or deformability of these portions 301a of the support 300, the lateral bodies 46, 47 - and therefore the emitter and the receiver - can assume the correct position relative to the relative optical surfaces of the site (such as surfaces 33a, 34a , see Figure 19 for reference), as previously explained, for example behind the thrust exerted by the locking and / or positioning member used (such as a member of the type indicated with 60 in Figure 20).

Naturally, the bodies 45-47 could have a different configuration from the one exemplified and be overmolded so as to define also thin, or in any case elastically deformable, connecting portions, which extend between the lateral bodies 46, 47 and the central body.

In further embodiments of the invention, one or more distinct positioning and / or support bodies is / are associated with a circuit support that integrates. An embodiment of this type is exemplified in figures 117-119, in which the same reference numbers of the previous figures are used, to indicate elements technically equivalent to those already described above.

Referring initially to figures 117 and 118, in various embodiments a flexible circuit support 300 is used for the purpose, for example of the type already described with reference to figures 112-115, integrating the conductors 48, 49 and the terminals 50 in the form of electrically conductive tracks.

With 41 'a single body is indicated on the whole in which three upper half-bodies are identified, and in particular a central half-body, indicated with 45', and two lateral half-bodies, indicated with 46 'and 47', intended to make an upper portion of the support and / or positioning bodies hereinafter indicated with 45, 46 and 47. In the example, the lateral half-bodies 46 'and 47' are joined to the central body through at least one connecting portion 160, preferably having a relatively thin configuration and / or flexible. The upper faces of the three half-bodies 45'-47 'are formed in order to define the necessary functional elements. For example, referring to figure 117, the half-body 45 'defines the stop protrusions 45b, the upper formation 51, the upper formation and the holes 502, as well as respective parts of the through openings, indicated here with 45a' and 51a '. The half-bodies 46 'and 47' instead define the relative seats 46a, 47a and appendices 46b, 47b.

With 45 ", 46" and 47 "are indicated three lower half-bodies, distinct from each other, intended to make a lower portion of the support and / or positioning bodies indicated below with 45, 46 and 47. In this perspective, as for visible example in figure 118, the lower half-body 45 "defines the formation 52, as well as respective parts 45a" and 51a "of the necessary through openings, as well as openings 170 to leave part of the terminals 50 exposed. The lower lateral half-bodies 46" and 47 "are instead substantially configured in the form of frames, each defining a respective passage 46e and 47e.

In various embodiments, the aforementioned support and / or positioning bodies, or the half-bodies 45'-47 'and 45 "and 46" that make them, are formed with a polymer, such as a thermoplastic or thermosetting material or a resin. Preferably, the material used is of a relatively rigid type, in particular if molded with a relatively high thickness, for example a thickness at least locally greater than 1 mm, in order to guarantee the necessary support and / or positioning functions. The connecting portions 160 can be made of the same material, providing them with joints or joints or hinges, or - as in the case exemplified - be substantially in the form of a sheet, or in any case with relatively small dimensions (such as for example a thickness of less than 1 mm), in order to ensure correct flexibility. Alternatively, the half-bodies 45'-47 "(and possibly the half-bodies 45" -47 ") can be made with a relatively rigid polymer and be co-molded or over-molded or associated with connection portions 160 made with another flexible material.

In various embodiments, the half-bodies 45'-47 'and the half-bodies 45 "-47" are provided with mutual coupling means, for example snap-fit and / or coupling and / or interference means. In the exemplified case, for example, in correspondence with the faces of the lower faces of the half-bodies 45'-47 'there are protrusions 180 or seats 190 intended for coupling with corresponding seats 190 and protrusions 180 provided in correspondence with the upper faces of the half-bodies 45 "- 47 ". In various embodiments, the aforementioned seats 190 are through seats, but in other possible embodiments these seats can be blind seats. As mentioned, the projections 180 can preferably be snap coupled into the relative seats 190. It is also possible to provide further elements for mutual positioning, such as for example seats 200 defined in correspondence with the upper face of the half-body 45 "(figure 117), intended for receiving corresponding protrusions 210 defined in the lower face of the half-body 45 '(figure 118), said seats and protrusions being designed to be in correspondence with the openings 300c of the substrate 3001 (figure 117). Protrusions 210 and seats 200 can also be provided on the half-bodies 46'-46 "and 47'-47", particularly in positions corresponding to those of the openings 300b of the substrate 3001, as shown for example in figures 117 and 118.

The half-bodies 45'-47 '(ie the body 41') and the half-bodies 45 "-47" can be molded separately, for example in polymer, and then be coupled together, with the circuit support 300 interposed, on the which the emitter 42 and the receiver 44a, 44b can be previously mounted, as shown in figure 118. For example, referring to the exemplified case, the lower face of the body 41 'is placed against the upper face of the support 300, so that the positioning projections 210, 210a slip through the openings 300b, 300c; on the other side, the upper faces of the half-bodies 45 "-47" are placed against the lower face of the support 300, so as to achieve the coupling between the projections 180, 210 and the corresponding seats 190, 200. The presence of the passages 46e , 47 and of the lower half-bodies 46 "and 47" allows the pre-assembly of the emitter and the receiver on the support 300. As mentioned, in the exemplified case, the projections 180 and seats 190 are configured for snap coupling, but their type of coupling - as well as their number and / or location - could be different.

Following the coupling between the half-bodies 45'-47 'and the half-bodies 45 "and 47", the optical module is defined, whose structure includes the bodies 45, 47 and 47, each of which formed by the relative half-bodies 45'-45 ", 46'-46" and 47'-47 ", as shown in figure 119, where the module is indicated as a whole with 405. Also in embodiments of this type, between the lateral bodies 46, 47 and the central body 45 remain exposed respective portions 301a of the support 300 which are flexible or deformable, as well as the intermediate body portions 160, which are also flexible or articulated. By exploiting the flexibility of these portions 301a of the support 300 and of the intermediate portions 160, the lateral bodies 45, 47 - and therefore the emitter and the receiver - can assume the correct position relative to the relative optical surfaces of the site (note, for this in this regard, that Figure 119 simulates, by way of example, a mounted condition of the module), behind the thrust exerted by the locking and / or positioning member used.

Obviously, instead of snap and / or clutch and / or interference coupling means, the half-bodies 45'-47 'and 45 "- 47" could be made integral with each other in another way, with the support 300 interposed, for example by gluing, or welding, or partial reflow of the same coupling means 180-210, if anyhow provided. It will also be appreciated that the presence of the intermediate connecting portions 160, although advantageous from the production point of view, in particular for easier handling, and possibly useful for protecting the conductive tracks of the support 300, is not strictly indispensable for the purposes implementation. Moreover, where deemed preferable, also the half-bodies 45 "-47" could be joined together in a single body by means of flexible intermediate portions similar to the portions indicated with 160. Intermediate connecting portions of the type indicated with 160 could also be provided in the case of embodiments of the type described with reference to Figures 112-115, in correspondence with the upper and / or lower face of the support 300, for example if it is desired to provide the module with a protection of the conductive tracks.

It will also be appreciated that a flexible circuit, for example of the type indicated with 300, could also be provided with metallic connection terminals 50 of a flexible type, for example of the type described with reference to Figures 7-9 or 91-93, particularly in case of overmoulding of the central body 45.

In possible variants of implementation, the body 41 'can be molded with the half-bodies 46' and 47 'already in an inclined configuration with respect to the half-bodies 45', for example as in figure 119, particularly exploiting the presence of the intermediate body portions 160; possibly for this purpose, also the half-bodies 45 "-47" could be joined to the half-body 45 "by means of intermediate body portions. Variants of this type are also applicable to the case of an overmoulded structure of the type shown in Figures 112-116m, particularly when the bodies 45-47 are joined together by means of intermediate body portions.

Obviously optical modules of the types described with reference to figures 112-116 and 117-119 can be used in all the embodiments described above.

It is evident to the person skilled in the art that single characteristics described in relation to an embodiment can be used in other embodiments described here, in various embodiments it is possible to realize a sensor device according to the invention comprising combinations of the single characteristics previously described, also different from the previous examples.

For example, all the various embodiments described can be implemented according to the teachings provided in relation to the embodiment of Figures 72-78. Similarly, the solution of providing at least one emitter and at least one receiver of an optical reference radiation with an interposed optical reference guide (such as the elements previously indicated with 421, 441, 372, 352) can be implemented in all forms of implementation.

In various embodiments, the closing or bottom structure of the body 10a could also include a portion of the peripheral wall 20 of the housing part 12 which protrudes towards the inside of the tank 1, or with the relative external surface in contact with the substance. liquid. In implementations of this type, the optical arrangement for detecting the quality and / or other characteristics of the substance could be associated with this protruding portion of the peripheral wall 20, which will be formed with material transparent to the working optical radiation of the optical sensor. For example, referring to the embodiment of figures 100-111, the seat 230 could be defined in correspondence with the aforementioned portion of the peripheral wall 20, with the latter shaped to define at least the surfaces 230a-230b (figures 101, 110).

In various embodiments, an optical formation or optical prism of the type previously indicated with 31, integrating at least part of the characteristics indicated in the preceding examples, at least partly transparent or permeable to optical radiation, is configured as a distinct or independent element which is mounted in a relative seat. For example, the optical formation or prism 31 described with reference to Figures 72-78 could be a distinct element, similarly to the shaped optical insert 120 of the example described with reference to Figures 100-111, while the relative seat 21c could have a bottom wall and / or walls transparent to optical radiation, similarly to seat 130.

As indicated, a sensor device of the type described above can be made with appropriate structural modifications - such as different angle � and / or emitter and / or receiver, in other embodiments and / or use, and / or can be used to detect characteristics of a fuel and / or to distinguish fuel blends, such as petrol-ethanol blends or diesel-biodiesel blends, or to detect possible contamination of a fuel.

As mentioned, a sensor device of the type described, comprising an optical sensor of the characteristics of a substance, can also be used in apparatuses other than vehicles, which include combustion or endothermic engines, such as for example electric generators.

The invention has been described with particular reference to tanks and generic containers of a liquid substance subject to detection, but the sensor device described is equally applicable to hydraulic pipes in which the liquid substance is contained and / or transits: in this perspective, the the terms "container" or "tank" previously used must also be understood as referring to generic pipes designed to contain and / or allow the transit of the substance subject to detection.

Claims (12)

CLAIMS 1. An optical sensor device for detecting at least one characteristic of a liquid substance, the sensor device (10; 10, 110) comprising a device body (10a; 10a, 110a) having an internal surface and an external surface, at least a portion of the external surface of the device body (10a; 10a, 110a) being intended to be in contact with the liquid substance and the internal surface of the device body (10a; 10a, 110a) being intended to be isolated from the liquid substance , wherein at least one detection arrangement is associated with the device body (10a; 10a, 110a) which comprises at least one emitter (42) and at least one receiver (44) of a given optical radiation (R), such as a visible radiation or in the 'infrared, wherein at least a first portion (31) of the device body (10a; 10a, 110a) is formed with a material suitable for the propagation of the determined optical radiation (R), the at least one emitter (42) and the at least one receiver (44) being optically coupled to the internal surface of the device body (10a; 10a, 110a) at said first portion (31), and wherein said first portion (31) of the device body (10a; 10a, 110a) is shaped to contribute to the propagation of the determined optical radiation (R), particularly by refraction and / or reflection, from the at least one emitter (42) to the 'at least one receiver (44), in such a way that the determined optical radiation (R) is at least partially propagated through said first portion (31) of the device body (10a; 10a, 110a) towards the at least one receiver ( 44) with an angle and / or intensity that is variable according to a characteristic of the liquid substance, wherein the at least one receiver (44) of the determined optical radiation (R) at least partially propagated through said first portion (31) of the device body (10a; 10a, 110a) comprises a first receiver (44a) and a second receiver (44b) in generally side by side positions. The sensor device according to claim 1, wherein the sensing arrangement comprises a control circuit arrangement (17) configured to detect, on the basis of electrical output signals (A, B) of the first receiver (44a) and of the second receiver (44b) a possible variation of a critical angle of reflection of the determined optical radiation (R) which is representative of a variation in the composition or concentration of the liquid substance. The sensor device according to claim 1 or claim 2, wherein the emitter (42), on the one hand, and the first and second receivers (44a, 44b), on the other side, have respective active parts of emission and reception, respectively, which are generally turned towards each other and arranged at an angle to each other, where: - the emitter (42), on one side, and the first and second receivers (44a, 44b), on the other side are arranged according to respective planes (42x, 44x) which form a first angle (� ) which is less than 90 °, particularly between 50 ° and 70 °, and / or - planes passing through the axes (42y, 44y) of the emitter (42), on one side, and of the first and second receiver (44a, 44b), on the other side, respectively, form an angle between them which is greater 90 °, and / or - the angle of incidence of the determined optical radiation (R) emitted by the emitter (42) relative to a relative interface surface (211) between the liquid substance and the material of said first portion is between 50 ° and 70 °. The sensor device according to any one of claims 1-3, wherein the sensing arrangement comprises an optical module (40; 404; 405), which includes an electrical connection and support structure (41; 414) of the emitter ( 42), on one side, and of the first and second receivers (44a, 44b) on the other side, the support and electrical connection structure (41; 414) being configured as a separate part with respect to the device body (10a; 10a, 110a). The sensor device according to claim 4, wherein the support and electrical connection structure (41; 414) includes one or more bodies (45-47) of electrically insulating material associated / associated, preferably by overmoulding, with connecting elements electric (48, 49, 50; 300) formed at least in part with electrically conductive material, the emitter (42) and the first and second receiver (44a, 44b) being associated with the one or more bodies. The sensor device according to claim 4 or claim 5, wherein the support and electrical connection structure (41) includes a central body (45) and two side bodies (46, 47) connected to the central body (45), preferably by means of body portions and / or electrical connection elements (48, 49; 301a) which are flexible or elastically deformable, with a first lateral body (46) being associated with the emitter (42) and with the second lateral body ( 47) being associated the first and the second receiver (44a, 44b), and where: - the emitter (42), on one side, and the first and second receivers (44a, 44b), on the other side, are positioned in correspondence with an internal side of the first lateral body (46) and of the second lateral body (47), respectively, or - the emitter (42), on one side, and the first and second receivers (44a, 44b), on the other side, are positioned in correspondence with an external side of the first lateral body (462) and of the second lateral body (472), respectively, the first lateral body (462) and the second lateral body (472) each defining a through opening (46d, 47d) for the passage of the determined optical radiation (R). The sensor device according to any one of claims 4-6, wherein - the internal surface of the device body (10a; 10a, 110a) is shaped in correspondence with said first portion (31) to define a positioning site (30 ) for the optical module (40), the positioning site (30) including at least one element (31) protruding at the internal surface of the device body (10a; 10a, 110a), - the at least one protruding element (31) of the positioning site comprises one or more optical elements (33, 34) for the propagation of the determined optical radiation (R) selected between an optical element (31) defining two planes inclined in opposite directions (33a, 34a) or a pair of optical elements (33, 34) each defining an inclined plane (33a, 34a), where the at least one emitter (42) faces an inclined plane and the other inclined plane faces the first and second receivers (44a, 44b). The sensor device according to claim 7, wherein at least one body (45) of the support and electrical connection structure (41) comprises positioning and / or locking means relative to the at least one protruding element (31) of the positioning site (30), the positioning and / or locking means preferably including at least one of - a relief (51) at least partially hollow, capable of housing at least partially the at least one protruding element (31) of the positioning site, - at least one through opening (51a) capable of housing at least partially the at least one protruding element (31) of the positioning site, - a relief (52a), capable of being received at least partially in a relative seat (32) defined in at least one protruding element (31) of the positioning site. The sensor device according to claim 7 or claim 8, further comprising a locking and / or positioning member (60; 601; 602), configured as a separate part with respect to the device body (10a; 10a, 110a) and to the support and electrical connection structure (41), the locking and / or positioning member (60; 601; 602) being arranged for engagement with the at least one protruding element (31) of the positioning site (30) in order to ensure the positioning of the optical module (40), where preferably the locking and / or positioning member (60; 601; 602) comprises one of: - an organ (60) engageable by interference with the at least one protruding element (31) of the positioning site (30), by means of an axial movement of said organ (60) relative to the at least one protruding element (31), - a member (602) engageable with at least one seat (35a) of the at least one protruding element (31) of the positioning site (30) by means of an angular or rotational movement of said member (602) relative to the at least at least one protruding element (31), - a member (601) which can be fixed in position by means of a relative stop element (80) which is engageable with at least one seat (35a) of the at least one protruding element (31) of the positioning site (30), the stop element (80) being preferably a substantially annular and elastically deformable stop element, - a member (601; 602) having an anti-rotation element (61b; 61e) capable of cooperating with a relative engagement seat (45a; 45a1) defined in a body (45) of the supporting and connecting structure of the optical module, - a member (60; 602) engageable by interference with at least one positioning and / or locking means (51) of a body (45) of the support and electrical connection structure (41). The sensor device according to any one of claims 4-9, wherein the support and electrical connection structure (41) comprises at least one of: - one or more bodies (45-47) over-molded to a plurality of electrical connection elements (48, 49, 50), - one or more bodies (45-47) over-molded to a flexible circuit support (300) which includes electrical connection elements (48, 49, 50), - a plurality of distinct bodies (45-47) connected to each other by means of electrical connection elements (48, 49; 300, 301a), - a plurality of distinct bodies, particularly molded bodies, associated with a flexible circuit support (300) which comprises electrical connection elements (48, 49, 50, 301a), - a plurality of bodies molded with electrically insulating polymeric material and electrical connection elements molded in an electrically conductive material comprising a polymer, said bodies and elements being preferably co-molded or overmoulded together, - a plurality of molded bodies (45-47) connected to each other and capable of varying their relative position, particularly a relative angular position, during the assembly of the optical module on the device body (10a; 10a, 110a). 11. An optical sensor device, particularly for a hydraulic system or a container of a liquid substance, such as a tank (1) of a motor vehicle, the sensor device (10; 10, 110) comprising a device body (10a; 10a, 110a) having associated at least one optical arrangement (15, 40; 15, 401; 15, 402; 15, 421, 441), the optical arrangement comprising at least one emitter (42; 421; 422) and at least one receiver (44; 441) ; 442) of an optical radiation (R) and being arranged for the detection of at least one characteristic of at least one of a liquid substance, a material of the device body (10a; 10a, 110a) which is permeable or transparent to optical radiation ( R) and a material of an optical prism (31) or an optical guide (315; 372) belonging to or associated with the device body (10a; 10a, 110a). 12. A method for making an optical sensor device for detecting at least one characteristic quantity of a liquid substance, the method comprises: a) providing a device body (10a; 10a, 110a) having an inner surface and an outer surface, at least a portion of the outer surface of the device body (10a; 10a, 110a) being intended to be in contact with the liquid substance and the internal surface of the device body (10a; 10a, 110a) being intended to be isolated from the liquid substance, b) providing a support and electrical connection structure (41) for at least one emitter (42), on one side, and a first and second receiver (44a, 44b), on the other side, of a given optical radiation (R) , such as visible or infrared radiation, the support and electrical connection structure (41) being configured as a separate part with respect to the device body (10a; 10a, 110a), c) optically coupling the at least one emitter (42), on the one hand, and the first and second receivers (44a, 44b), on the other side, to the internal surface of the device body (10a; 10a, 110a) in correspondence of said portion, wherein step a) comprises forming at least a first portion of the device body (10a; 10a, 110a) with a material suitable for the propagation of the given optical radiation (R), said first portion being shaped to contribute to the propagation of the given optical radiation (R), particularly by refraction and / or reflection, from the at least one emitter (42; 422) to the first and second receiver (44a, 44b), so that the determined optical radiation (R) is at least partially propagated through said first portion of the device body (10a) towards the first and second receivers (44a, 44b), with an angle and / or with an intensity which is variable according to a characteristic of the liquid substance.