DE102004022946A1 - Force dependent pushbutton for controlling electric cooker has flat transparent top plate connected to printed circuit board mounted on spring and has photodiodes and photocells - Google Patents

Abstract

The force dependent pushbutton has a flat transparent top plate (4) connected to a printed circuit board (3) by optical switch units (8,9) fed with square-wave signals. Each switch unit acts as a spacer and has a light barrier (7). A photodiode (1) and a photocell (2) are mounted on either side of the light barrier. The switches are soldered (18) to the printed circuit board using SMD (Surface Mounted Device) technology. The signals generated by the photocells change as a user's finger approaches the button. A force sensor (11) is soldered to the printed circuit board and may sense relative motion of the top plate. The printed circuit board is mounted on a spring (22).

Description

The The invention relates to a sensing device for controlling a Consumer supplied electrical Signal, in particular a sensing device for controlling a household appliance such as a stove top.

A sensing device of the type mentioned is disclosed for example in the DE 296 03 484 U1 wherein the radiation is preferably an infrared radiation which is reflected on the surface of a shadowing finger. The receiver provides a corresponding output signal that follows an on and off clock of the transmitter. If extraneous light influences are present, these are superimposed by the clock of switching on and off, whereby the signal component with this clock is used for the evaluation. If the receiver receives ambient light or artificial light during non-shading, this influence of light does not have the switch-on and switch-off characteristics of the transmitter. From the evaluation circuit, the corresponding signal supplied by the receiver to form the control signal is not evaluated. The control signal is generated only when the output signal provided by the receiver includes a portion having the on and off cycle of the transmitter.

In Such sensing devices have so far only been present a shading or reflection detected by the tactile actuation, evaluated and used to control the consumer. The The manner of the tactile movement or tactile operation of an operator is thus not detectable. this leads to to the disadvantage that accelerated changing of the control signal at intuitively faster or stronger Tasting movement, for example, when overcooking a food not is possible.

sensing devices such as touch sensors are from the music keyboard technique known, with keyboards, for example, with a touch sensor and equipped with an associated pressure sensor, so that the pressure intensity of the keystroke can be used as a tax value. This requires, however a high production cost, because for each key its own pressure sensor must be arranged. Also a time measurement between the switching two contacts became this already proposed.

Furthermore, in the publications DE 101 48 473 A1 and DE 199 52 560 C2 Force torque sensors for controlling a motor vehicle seat or a computer disclosed, wherein the force acting on a control panel of the force torque sensor forces and torques detected and used for position control of the object to be controlled.

It Object of the present invention is a sensing device for to provide intuitive control of a consumer with preferably minor changes The above-mentioned prior art is feasible.

These The object is achieved by the Characteristics of claim 1 solved.

By providing the on the carrier plate arranged or mechanically coupled with this sensor a direct or indirect detection of the type of tactile movement over the associated pressure force possible. Because an accelerated tactile operation also to a higher one Pressure force leads, The desire of the operator for a faster change process the control signal directly over the pressure force can be detected. This allows intuitive control of the consumer.

The suggested solution is by slight Modifications of the known sensing device feasible, since only transferred to the carrier plate Pressing force must be detected so that the sensor on any Place on the backing plate or can be arranged mechanically coupled with this. The sensor can thus in a simple way as additional, automatically equippable Component designed, for example, in SMD technology, on the conductor Circuit board arranged and a plurality of individual touch sensors be associated with the sensing device.

Especially can the recipient and the sensor with printed conductors of a printed circuit board, which the carrier plate forms, for connected to the electrical connection to the evaluation be.

Further, the transmitter, the receiver and the sensor may be covered by a translucent plate, wherein the pressing force is transmitted via spacers on the carrier plate. These spacers can then form eg shielding elements between the transmitter and the receiver. In this case, for example, at least two switching units each having the transmitter and the receiver may be provided with connected evaluation device for controlling the consumer signal, wherein the one switching unit for increasing the consumer signal and the other switching unit for reducing the consumer signal, wherein the two switching units side by side on the Support plate are arranged, and wherein the sensor is arranged at a location independent of the location of the two switching units and for detecting the pressing force of both switching units is used. The consumer may be a heating station of an electric oven, wherein the two switching units are arranged under a translucent designed as a worktop plate. The carrier plate can then be pressed by spring force in the direction of the underside of the translucent plate. This is advantageous, for example, in a hob with ceramic hob.

The Evaluation device can be designed so that the amount of change of the consumer signal in dependence the strength the pressure applied by the sensor is controlled. It can For example, the speed of the increase of the consumer signal be dependent on the measured pressure force in an auto-repeat mode. Furthermore, the evaluation device can be designed such that it detects the signal rise gradient of the output signal of the sensor and evaluates.

Of the Sensor can also be designed as a capacitive sensor. The sensor can also be designed so that it detects the bending of the support plate. in this connection the sensor may comprise a strain gauge. The sensor may further comprise a silicon substrate and thus on silicon material based. The evaluation device can be integrated on the sensor be.

The Invention will be described below with reference to a preferred embodiment explained in more detail with reference to the drawing figures. Show it:

1 a plan view of an arrangement of a plurality of sensing devices on a worktop of an electric range;

2 a sectional view as an example of the structural design of a sensing device according to the preferred embodiment; and

3 a block diagram of the electrical interconnection of the sensing device according to the preferred embodiment.

Preferably, the proposed sensing device according to the preferred embodiment in the control of the power supply of heating points of an electric range is used. At the in 1 illustrated embodiment, four sensing devices are provided, each of which two switching units 8th and 9 to reduce or increase the supply. According to 3 can the surfaces of the switching units 8th and 9 be formed substantially square with rounded corners, with one side, for example, about 16 mm. Depending on the duration of the actuation of the respective switching unit 8th respectively. 9 From the control signal is a display device consisting of several arranged in a row luminous display elements 17 , driven. These illuminated display elements 17 can consist of light emitting diodes. The surfaces of the lined-up illuminated display elements 17 differ from each other. The illuminated display elements 17 , which in addition to the supply current increasing switching unit 9 lie, have larger areas than the illuminated display elements 17 , which next to the switching unit 8th to reduce the supply. The row of illuminated display elements 17 is according to 3 parallel to the arrangement of the associated two switching units 8th and 9 arranged. Starting from the one end to the other end, the surfaces of the illuminated display elements can 17 rejuvenate straight. This can be an immediate indication of the supply to the consumer, here a heating station 10 , be won. The operator can immediately see if all the available supply or a certain fraction of it is being supplied to the consumer.

2 shows a side sectional view of the in 1 shown sensing devices along the line X-X '.

The illustrated embodiment of the sensing device includes the two switching devices 8th and 9 , Each switching device 8th and 9 contains a transmitter 1 , For example, a photodiode which emits radiation, in particular infrared radiation. Furthermore, each switching unit has a receiver 2 which is the one from the sender 1 can receive emitted radiation and provides a corresponding output signal. Between the transmitter 1 and the receiver 2 is a light barrier 7 arranged. The light barrier 7 prevents not operated tactile device that from the transmitter 1 emitted radiation to the receiver 2 arrives.

The actuation of the respective switching unit 8th respectively. 9 done by shading. The shading can be done by placing a finger of an operator on top of the respective switching unit 8th respectively. 9 respectively. When shading is the transmitter 1 emitted radiation on the surface of the applied finger or Abschattungsgegenstands reflected and reaches the receiver 2 , To the one from the transmitter 1 To identify emitted radiation or to provide it with a specific characteristic, the radiation of the transmitter 1 be switched on and off with a certain clock. It is provided for this purpose a corresponding clock control device. Also from the receiver 2 received radiation has this clock. The recipient 2 generates an output signal having this on-off clock.

Preferably, the material is the light barrier 7 made of a soft material, especially silicone. In the illustrated embodiment of the 1 can the transmitter 1 and the receiver 2 be embedded in a shaped body of the soft material. The switching units 8th and 9 are on a backing plate 3 , which may be formed as a printed circuit board arranged. With the tracks of the carrier plate or printed circuit board 3 The switching devices are, for example in SMD technology via solder joints 18 or other suitable contacts. In this way, the electrical connection of the switching units takes place 8th and 9 with the evaluation circuit and the illuminated display elements. About the switching units 8th and 9 is a transparent plate 4 , for example made of glass. This forms the worktop, for example, a ceramic hob of an electric cooker. The consumers 10 this electric stove are the corresponding heating points 10 according to 1 , The overall height of the printed circuit board 3 , the switching units 8th and 9 and the glass plate 4 may be, for example, 34 mm and is ensured by appropriate spacers (not shown) placed at suitable locations between the carrier plate 3 and the glass plate 4 are arranged. Moldings with embedded transmitters 1 and / or recipients 2 For example, can already form the spacer, so that no additional elements are required.

The carrier plate 3 is due to the power of a spring 22 in the direction of an arrow 23 to the underside of the transparent plate 4 pressed against the spacers. This also makes the soft material of the light barrier 7 in possibly existing unevenness and roughness on the underside of the particular as a glass plate 4 formed translucent plate pressed. This makes it possible at the bottom of the glass plate 4 one the strength and stability of the plate 4 increasing mat, which has a certain roughness, apply. Instead of the additional mat can provide the required strength and stability of the plate 4 be achieved by a glass structure in or on the plate. The roughness, which originate from this mat, are filled by the depressed soft material of the light barrier, so that a transition of radiation between the transmitter and receiver is prevented in Nichtabschattung.

For detecting the pressing force of a touch operation on the switching units 8th and 9 is a sensor 11 vorgese hen, on the support plate 3 is arranged directly or mechanically coupled with this. Preferably, the sensor 11 in SMD technology on the carrier plate designed as a printed circuit board 3 attached and via appropriate solder joints 18 be contacted with the connecting cables. The sensor 11 can be used as direct or indirect force or pressure sensor to detect the pressure force of all switching units 8th and 9 the in 1 shown sensing device or caused by the pressing force bending of the carrier plate 3 be provided, ie for the entire sensing device is only a sensor 11 required. The on the switching units 8th respectively. 9 acting on the tactile actuation pressure force is applied via the spacers on the carrier plate formed as a printed circuit board 3 forwarded to where of the sensor 11 is detected. The sensor 11 can be used as a direct force sensor for direct detection of the on the carrier plate 3 be formed acting tensile or bending force. Alternatively, the sensor 11 be designed as an indirect force sensor, in which case caused by the bending expansion or contraction of the support plate 3 is detected. In this case, the sensor can 11 For example, have at least one strain gauge. As another alternative, the sensor 11 be constructed as a capacitive sensor, the force measurement indirectly by changing a capacitance due to the dimensional changes caused by the force of the support plate 3 he follows. Of course, it is also possible to provide a plurality of sensors at different locations in order to carry out a differentiated force measurement.

It should be noted that the sensor 11 at any point of the carrier plate 3 can be arranged, and 2 only shows an exemplary arrangement position. For example, the sensor 11 also between the switching units 8th and 9 or on the underside of the carrier plate 3 be positioned.

The design as an SMD component has the advantage that the extension of the sensing device for detecting the pressing force by simple modification of the printed circuit board for receiving the additional sensor 11 can be achieved.

3 shows a schematic block diagram of the electrical interconnection of the sensor 11 and the switching units 8th and 9 with the evaluation device 5 , According to 2 is to the respective recipient 2 the switching units 8th . 9 the evaluation device 5 , for example connected in the form of a microprocessor. The evaluation device 5 contains a clock monitoring 12 , with which it is determined whether the output signal of the respective receiver 2 corresponds to the on / off clock of the emitted radiation. Output signals of the receiver, which have no signal component with this on and off clock, are judged as not to be evaluated signals and from the off values facility 5 not treated further. Such output signals of the receiver may result from extraneous or artificial light. This ensures that always only if one of the two switching units 8th . 9 is operated by shading, an associated control signal from the evaluation 5 is produced. In addition, the evaluation device 5 contain a filter that filters out signals that correspond to external or artificial light.

If the sensor 11 is produced on a substrate base such as, for example, a silicon substrate, the evaluation device 5 also directly on the sensor 11 be integrated, resulting in a space-saving design.

If from one of the two receivers 2 an output signal is supplied with the described clock, this signal is after clock monitoring 12 by a time comparator 13 with a given time, in a corresponding memory 14 is predetermined for a time limit compared. If the time comparison shows that the output signal matches the clock of the transmitter 1 is shorter than the predetermined time limit, eg 5 seconds, the signal is sent to a control signal device 15 forwarded to generate a control signal. In the control signal device 15 is dependent on the duration of the output signal of the receiver 2 with the described clock, a control signal for a control device 19 for adjusting the supply power of the consumer 10 educated.

The switching unit 8th serves to reduce the power supply and the switching unit 9 serves to increase the supply. So that the control signal device 15 , which forms the control signal, detects which of the two switching units has been actuated or shaded, become the output signals of the receiver 2 via lines 20 and 21 corresponding inputs of the control signal device 15 fed. The output signal of the switching unit 9 is over the line 20 a (+) designated input of the control signal device 15 fed, and the output of the switching unit 8th is via the supply line 21 an input designated by (-) of the control signal device 15 fed. The output signal of the receiver 2 the switching unit 9 serves to increase the power supply, and the output signal of the receiver 2 the switching unit 8th serves to reduce the supply power. Corresponding control signals are for the control device 19 educated. The reduction and increase in power depends on the duration of the respective shading of the switching unit 8th respectively. 9 from.

By the time comparison in the time comparison device 13 ensures that with longer shading, for example, by spilled liquid or by one on the surface of the switching units 8th . 9 deposited object the formation of a control signal is prevented. In these cases, the time comparator device 13 determines that the shading is longer than the prescribed time limit, which in the memory 14 is stored, and it is then the formation of a control signal by the control signal device 15 prevented. Depending on the control signal, the display is made on the corresponding illuminated display element 17 and the controller 19 leads a corresponding supply to the consumer 10 to.

The sensor 11 is about a force detector 30 with the control signal device 15 connected. The force detection device 30 converts the output signal of the sensor 11 in a pressing force corresponding signal size and performs the output signal of the control signal device 15 to. The control signal device 15 For example, it may be configured to match the signal rise gradient of the output of the force detection device 30 determined and the increase step for the the controller 19 supplied control signal, for example, increases in proportion to the determined signal rise gradient. This will increase the speed with which the consumer 10 For example, in an auto-repeat mode is switched higher / lower, depending on the pressing force changed when the finger remains on the key. This allows intuitive control of the increase or decrease of the consumer 10 supplied power. The sensor 11 thus detects the pressing force, and the consumer power, ie, for example, the cooking level of the electric range is increased or decreased depending on the strength of the force. In addition, a control may be provided such that a strong pressing force is applied to the incremental switching unit 9 to fully turn on the consumer 10 leads, while a weak pressure force on the switching unit 9 only leads to a step-up by one stage. Similarly, a strong force leads to the reduction unit provided for switching 8th to completely switch off the consumer 10 while a weak force on the switching unit 8th to downshift the load power or the load current by one stage leads. The determination as to the presence of the strong force or the weak force can be made by corresponding in the control signal device 15 stored thresholds. The above-described speed change in the auto-repeat mode can then be provided between these two threshold values. Thus, an advantageous control of the load current is achieved as a function of the contact pressure caused by the pressing force.

For suppressing interference by on the glass plate 4 acting pressure forces due to the food or other not caused by a tactile forces, a blanking can be provided such that only a combined presence of optical detection by shading and a force detection on the sensor 11 lead to a change in the control signal. This ensures that only caused by a tactile force on the support plate 3 an impact on the power controller 19 causes.

In summary It should be noted that the sensing device described above with evaluation of the pressing force not on the present embodiment limited is, but in any kind of controls with sensing device for any Applications can be used to thereby an intuitive operation control to enable. The embodiments can Therefore, within the scope of the attached claims be modified.

Claims (16)

Sensing device for controlling a consumer supplied electrical signal with a transmitter and a receiver, which are optically or capacitively coupled to each other, wherein the degree of coupling is variable by touching the sensing device, and wherein the transmitter and the receiver are arranged on at least one support plate and the Receiver is electrically connected to an evaluation device, characterized by a on the support plate ( 3 ) or with this mechanically coupled sensor ( 11 ) for directly or indirectly detecting a on the support plate ( 3 ) and caused by the contact pressure, wherein an output signal of the sensor ( 11 ) and the evaluation device ( 5 ) is supplied and the evaluation device ( 5 ) a control signal in response to the detected sensor signal and an output signal of the receiver ( 2 ) generated. Sensing device according to claim 1, characterized in that the receiver ( 2 ) and the sensor ( 11 ) with printed conductors of a printed circuit board, which the carrier plate ( 3 ), for the electrical connection to the evaluation device ( 5 ) are connected. Sensing device according to claim 2, characterized in that at least the sensor ( 11 ) is designed as an automatically equipable component. Sensing device according to one of the preceding claims, characterized in that the receiver ( 2 ) and the sensor ( 11 ) from a translucent plate ( 4 ) are covered and the pressure force on spacers on the support plate ( 3 ) is transmitted. Sensing device according to claim 4, characterized in that the spacer as a shielding element between the transmitter ( 1 ) and the recipient ( 2 ) is trained. Sensing device according to claim 4, characterized in that at least two respectively the transmitter ( 1 ) and the recipient ( 2 ) having switching units ( 8th . 9 ) with connected evaluation device ( 5 ) are provided for controlling the consumer signal, wherein the one switching unit ( 9 ) to increase the consumer signal and the other switching unit ( 8th ) serve to reduce the consumer signal that the two switching units ( 8th . 9 ) side by side on the carrier plate ( 3 ) and that the sensor ( 11 ) at one of the locations of the two switching units ( 8th . 9 ) is arranged to record the pressing force of the switching units ( 8th . 9 ) serves. Sensing device according to claim 4 or 5, characterized in that the consumer 10 is a heating station of an electric cooker and that the two switching units ( 8th . 9 ) under a translucent plate designed as a worktop ( 4 ) are arranged. Sensing device according to one of claims 4 to 6, characterized in that the carrier plate ( 3 ) with spring force towards the bottom of the translucent plate ( 4 ) is pressed. Sensing device according to one of the preceding claims, characterized in that the evaluation device ( 5 ) is configured so that the amount of change of the consumer signal in dependence on the strength of the sensor ( 11 ) detected pressing force is controlled. Sensing device according to claim 8, characterized in that that the speed of increase of the consumer signal in an auto-repeat mode of the measured Pressing force dependent is. Sensing device according to one of the preceding claims, characterized in that the evaluation device ( 5 ) the signal rise gradient of the output signal of the sensor ( 11 ) recorded and evaluated. Sensing device according to one of the preceding claims, characterized in that the sensor ( 11 ) is configured to detect a bending of the carrier plate ( 3 ). Sensing device according to claim 11, characterized in that the sensor ( 11 ) comprises a strain gauge. Sensing device according to one of claims 1 to 10, characterized in that the sensor ( 11 ) is a capacitive force sensor. Sensing device according to one of the preceding claims, characterized in that the sensor ( 11 ) has a silicon substrate. Sensing device according to one of the preceding claims, characterized in that the evaluation device ( 5 ) on the sensor ( 11 ) is integrated.