JP2014006171A - Non-contact liquid detection structure - Google Patents

Abstract

An object of the present invention is to provide a non-contact liquid detection configuration that can increase the availability of parts by preventing a decrease in the amount of light transmitted from a liquid, reduce the power consumption required for detection, and can be widely used in electrical equipment. .
A light-emitting element 4 for storing light at an angle other than vertical is disposed outside a container body 1 that stores liquid and transmits light, and a light-receiving element 5 that outputs an electrical signal corresponding to the amount of received light. 1 is configured to receive light in the traveling direction of light in a state where there is a liquid inside, and further, a light transmission plane portion substantially perpendicular to the traveling axis of light on the surface of the container body 1 through which light is transmitted to the light receiving element 5 9, if the increase in the amount of received light can be determined from the change in the electrical signal of the light receiving element 5, the state in which the liquid is present is determined. Since the reduction of transmitted light amount is suppressed, the range of elements to be used is widened to increase the availability, the power consumption required for detection can be reduced, and non-contact liquid that can be widely used in general electrical equipment A detection configuration can be obtained.
[Selection] Figure 1

Description

  The present invention relates to a non-contact liquid detection configuration for detecting the presence / absence of a liquid in a container mounted on an electric device that uses a transparent liquid such as water stored in the container without contacting the liquid from the outside of the container.

  Conventionally, this kind of transparent liquid non-contact liquid detection configuration irradiates the surface of the liquid with an ultrasonic signal and detects the presence or absence of liquid from the change in the reflection time of the ultrasonic signal from the liquid surface. This configuration is known as a typical method. However, since the price of an ultrasonic element that transmits and receives ultrasonic signals is very expensive, high accuracy is required for expensive measuring instruments and liquid detection. For example, the configuration is not used widely in general electrical equipment such as a humidifier that uses water to perform air humidification using water.

  As a configuration that is relatively inexpensive and can be used in general electrical equipment, the difference in absolute refractive index between the liquid and air stored in the light causes the refraction law that light incident on the interface between air and liquid from an oblique direction is refracted at the interface. For example, a light emitting element and a light receiving element are arranged opposite to each other outside a container made of a light transmissive body, light is output from the light emitting element, and the output light is transmitted through the container. A device that detects the presence or absence of a liquid by utilizing an action that changes the amount of light received by a light receiving element by being refracted at the boundary surface between the container and the liquid is known (for example, see Patent Document 1).

  Hereinafter, the non-contact liquid detection configuration will be described with reference to FIGS. 9 and 10.

  As shown in FIG. 9, the conventional configuration includes a liquid 101 to be detected stored inside the container body 100 outside the corner portion of the container body 100 that stores liquid made of a material that transmits infrared light such as polyethylene. An infrared light emitting element 103 that emits infrared light is disposed so that infrared light is incident at an angle other than perpendicular to a boundary surface 102 with which the inner surface of the container body 100 is in contact, and extends in an extension direction of the incident direction. An infrared light receiving element 104 that outputs an electric output signal proportional to the amount of received infrared light is arranged in such a manner that the corner of the container body 100 is sandwiched from the outside, and an electric output signal output from the infrared light receiving element 104 is further provided. The control circuit unit 105 that performs a process for determining whether or not there is a liquid based on the change in the number of times is provided.

  With this configuration, the infrared light output from the infrared light emitting element 103 is substantially incident in the incident direction as indicated by the dotted arrow line in the figure when the liquid 101 to be detected is not present inside the container body 100. When the liquid to be detected is transmitted through the corner of the container body 100 on the extension line and the liquid to be detected 101 is present inside the container body 100, the absolute surface of the air and the liquid to be detected 101 at the boundary surface 102 between the container body 100 and the liquid to be detected 101. By refracting based on the law of refraction due to the difference in refractive index, it reaches an extension line different from the state in which the liquid to be detected 101 is not present inside the container body 100 as indicated by the solid arrow line in the figure. It will be.

  Therefore, the amount of infrared light transmitted to the infrared light receiving element 104 side changes due to the refraction of infrared light depending on the presence or absence of the liquid 101 to be detected, and the presence or absence of the liquid 101 to be detected from the infrared light receiving element 104. Since different electrical output signals are output accordingly, the presence or absence of the liquid 101 to be detected inside the container body 100 is detected by determining the change of the electrical output signal by the control circuit unit 105.

  In addition, as shown in FIG. 10, the infrared light emitting element 103 and the infrared light receiving element 104 are disposed opposite to each other with the transparent pipe 106 through which the liquid 101 to be detected is passed obliquely, so that the container can be determined in the same manner as described above. In this configuration, the presence or absence of the liquid 101 to be detected inside the body 100 is detected.

JP 2000-329609 A

  In such a conventional non-contact liquid detection configuration, the infrared light emitting element 103 and the infrared light receiving element 104 are arranged to face each other with the corner of the transparent container 100 or the transparent pipe 106 sandwiched obliquely. Infrared light emitted from the infrared light emitting element 103 is incident on the boundary surface 102 with the liquid to be detected 101 at an angle other than vertical, so that the infrared light incident on the inside of the container body 100 or the transparent pipe 106 is reflected. A configuration in which the presence or absence of liquid can be detected in a non-contact state based on the fact that the traveling direction is refracted by the presence or absence of the liquid 101 to be detected and the amount of transmitted infrared light toward the infrared light receiving element 104 changes. there were.

  However, the absolute refractive index of light is almost 1 in the air, and is 1.3 or more in liquids such as water and solids such as resin and glass. When the light is incident obliquely on the outer wall, the light is refracted in an acute angle direction with respect to the incident angle at the incident interface from the air in the surrounding space to the liquid inside, but from the liquid to the surrounding space. In the incident interface in the direction of air, the light is refracted in a wider angle direction than the incident angle and transmitted in the direction of the space, while a part is reflected and returned in the direction of the liquid.

  For example, when the liquid is water, if the incident angle is about 49 ° or more, which is generally called a critical angle, it is totally reflected and stays inside the container or pipe, and enters the liquid even within this critical angle. A large part of the light is reflected in the direction of the liquid and the transmitted light is reduced.

  In addition, it is necessary to consider the decrease in the amount of transmitted light due to dust and dirt adhering to the container in long-term use, but water-using devices such as humidifiers that continue operation if the mounted electrical device has water to be detected, for example If this is the case, the decrease in the amount of light received by the light receiving element can be determined by determining whether there is no water and no light is transmitted based on dust or dirt. Encouraging users to maintain the water supply and equipment cleaning is a fail-safe operation.

  From this, if a device such as a humidifier that continues operation if there is liquid is a target to be mounted, the amount of light received by the light receiving element increases when the light emitting element and the light receiving element have liquid, that is, when incident light is refracted. In the state where there is no liquid, the amount of light received by the light receiving element changes more greatly, and the larger difference in the amount of light received at that time is advantageous for stable liquid detection.

  Therefore, it is important to set the arrangement angle of the light emitting element and the light receiving element with respect to the container for stable liquid detection. However, more than this angle setting, it is necessary to take into account the reduction in the amount of transmitted light due to reflection. Become.

  From the above, considering the decrease in the amount of transmitted light, in general, a light emitting element with a high light emission efficiency is used, the light emission intensity is increased by increasing the applied power, or the high light receiving conversion efficiency is improved. It is necessary to select parts that are expensive and poorly available for detection, such as taking measures using a light receiving element, and more power is required. It had problems that were inferior in terms.

  Therefore, the present invention solves the above-described conventional problems, and suppresses the decrease in the amount of transmitted light from the liquid in the direction of the light receiving element, thereby selecting the light emitting efficiency of the light emitting element and the light receiving conversion efficiency of the light receiving element. By increasing the availability of elements that can be used with a wider range of specification conditions, and reducing the power consumption for detection, a non-contact liquid detection configuration that can be widely installed in general electrical equipment The purpose is to provide.

  In order to achieve this object, the present invention provides a container body provided with a space for transmitting light and storing liquid therein, a light emitting element for irradiating light from the outside to the inside of the container body, In the configuration provided with a light receiving element that transmits light emitted from the light emitting element from the inside of the container body to the outside and outputs an electric signal corresponding to the amount of received light, arranged outside the container body, The light emitting element is disposed so that light is incident on the surface of the container body at an angle other than perpendicular, and the light receiving element is located at a position where the incident light reaches in a state where there is liquid inside the container body. The planar shape of the container body is substantially vertical when the center of the optical axis of the received light is transmitted from the inside of the container body to the outside. The light transmission plane portion is provided to increase the amount of received light. Is obtained by so as to determine if the state is the sectional inside of the container body and the liquid is present, thereby it is to achieve the intended purpose.

  The present invention also provides a container body having a space for transmitting light and storing liquid therein, a light emitting element for irradiating light to the outside of the container body, and receiving light emitted from the light emitting element. A light receiving element that outputs an electrical signal corresponding to the amount of light received is arranged above the liquid surface, and the light emitting element is incident on the surface of the container upward at an angle other than perpendicular. In some cases, the incident light is arranged to cause total reflection on the surface of the liquid having a depth defined in the extending direction in which the liquid travels in a state where the liquid is present inside the container body. A reflection surface that reflects so that the center of the traveling axis of the light whose traveling direction has changed due to reflection is incident substantially perpendicular to the liquid surface is provided, and the light receiving element is reflected by the reflecting surface and the traveling direction is changed. As an arrangement to receive light, Increase in the output of the light receiving amount from a change in electrical signal of was made to determine that the liquid is in the interior of the container if the state is determined.

  According to the present invention, a container body provided with a space for transmitting light and storing liquid therein, a light emitting element for irradiating light from the outside to the inside of the container body, and the light emitted from the light emitting element In the configuration including a light receiving element that is transmitted from the inside of the container body to the outside and outputs an electric signal corresponding to the amount of light received, the light emitting element is provided on the container body. It is arranged so that light is incident at an angle other than perpendicular to the surface, and the light receiving element is located at a position where the incident light reaches in the state where the liquid is present inside the container body, and the extending direction of the center of the traveling axis of the light The container body is provided with a light transmission plane portion having a planar shape that is substantially vertical when the center of the optical axis of the received light is transmitted from the inside of the container body to the outside. If it is in a state where an increase in the amount of received light is determined, the container body By determining that there is liquid inside, the difference in the amount of received light between the state without liquid and the state with liquid can be made more conspicuous, so the selection of the light emission efficiency of the light emitting element and the light receiving conversion efficiency of the light receiving element Since the availability of elements that can be used increases as the range of specification conditions increases, and the power consumption for detection can be reduced, it can be used more widely in general electrical equipment. There is an effect that it can be easily performed.

  Further, according to the present invention, a container body having a space for transmitting light and storing a liquid therein, a light emitting element for irradiating light to the outside of the container body, and light received by the light emitting element are received. A light receiving element that outputs an electrical signal corresponding to the amount of light received is disposed above the liquid surface, and the light emitting element is incident upward at an angle other than perpendicular to the surface of the container body. When the incident light is arranged to cause total reflection on the liquid surface having a depth defined in the extending direction in which the incident light travels in a state where the liquid is present inside the container body, A reflecting surface that reflects the light so that the center of the traveling axis of the light whose traveling direction has changed due to total reflection is incident substantially perpendicular to the liquid surface, and the light receiving element is reflected by the reflecting surface so that the traveling direction is As an arrangement to receive the changed light, If it is in a state where an increase in the amount of received light is determined from the change in the electrical signal output from the optical element, the amount of received light in the state where there is no liquid is determined by determining that there is liquid inside the container. This makes the difference between the light-emitting element and the light-emitting element light-emitting element and the light-receiving element light-receiving conversion efficiency wide. Therefore, it is possible to obtain an effect that it can be more widely mounted and easily used for general electric devices.

The front view which fractured | ruptured and showed the structure of the principal part of the non-contact liquid detection structure of Embodiment 1 of this invention Front view showing another configuration of the main part of the non-contact liquid detection configuration broken. Front view of the main part of the non-contact liquid detection configuration in a simplified and broken state The front view which fractured | ruptured and showed the structure of another example of the principal part of the liquid detection structure The front view which fractured | ruptured and showed the structure of another example of the principal part of the same liquid detection structure The front view which fractured | ruptured and showed the structure of the principal part of the non-contact liquid detection structure of Embodiment 2 of this invention Front view of the main part of the non-contact liquid detection configuration in a simplified and broken state The front view which fractured | ruptured and showed the structure of the principal part of another example of the same liquid detection structure Cross-sectional configuration diagram showing an enlarged configuration of the main part of a conventional non-contact liquid detection configuration Cross-sectional configuration diagram showing the configuration of the main part of the non-contact liquid detection configuration broken

  The non-contact liquid detection configuration according to claim 1 of the present invention includes a container body provided with a space for transmitting light and storing liquid therein, a light emitting element for irradiating light from the outside to the inside of the container body, In a configuration comprising a light receiving element that transmits light emitted from the light emitting element from the inside of the container body to the outside and outputs an electric signal corresponding to the amount of light received from the container body. The light emitting element is disposed so that light is incident on the surface of the container body at an angle other than perpendicular, and the light receiving element is in a position where the incident light reaches in a state where there is a liquid inside the container body, An arrangement for receiving light in the direction of extension of the center of the traveling axis of light, and the container body is a plane that is substantially vertical when the center of the optical axis of the received light is transmitted from the inside of the container body to the outside The shape of the light transmission flat part is provided, and the increase in the amount of received light is If the condition to be cross the interior of the container body has a structure that was to determine the liquid is present.

  That is, the container body includes a planar light transmission plane portion that is substantially perpendicular to the center of the optical axis of the light received by the light receiving element, and the light receiving element emits light irradiated by the light emitting element in a state where there is liquid inside. In this configuration, when the light transmitted through the transmission plane portion is received, and the increase in the amount of received light can be determined from the change in the electrical signal output from the light receiving element, the state where the liquid is present is determined.

  As a result, when there is a liquid inside, the light transmitted through the light transmission plane portion is incident substantially perpendicularly, so that the reflection to the inside of the liquid is minimized and the decrease in the amount of transmitted light is suppressed. In contrast, it is possible to increase the amount of light received in a state where there is a liquid.

  In other words, the difference in the amount of received light between the state without liquid and the state with liquid can be made more conspicuous, so it can be used by widening the range of specification conditions for the light emitting efficiency of the light emitting element and the light receiving conversion efficiency of the light receiving element. Since the availability of the elements that can be increased and the power consumption for detection can be reduced, it is possible to more widely mount and easily use general electric devices.

  Further, in the non-contact liquid detection configuration according to claim 2, the optical element is located at a position where incident light arrives without any liquid inside the container body, and emits light in an extending direction of the center of the light traveling axis. The container body is provided with a light-transmitting flat portion having a planar shape that is substantially vertical when the center of the optical axis of the received light is transmitted from the inside of the container body to the outside. If it is in a state where an increase in the amount is determined, it may be determined that there is no liquid inside the container body.

  That is, the container body has a planar light transmission plane portion that is substantially perpendicular to the center of the optical axis of the light received by the light receiving element, and the light receiving element emits light irradiated by the light emitting element when there is no liquid inside. In this configuration, light that has passed through the transmission plane portion is received, and when the increase in the amount of received light can be determined from the change in the electrical signal output from the light receiving element, the state without liquid is determined.

  As a result, in the state where there is no liquid inside, the light transmitted through the light transmission flat part is minimized in reflection in the inner direction of the container body and the decrease in the amount of transmitted light is suppressed. The amount of light received in the absence of liquid can be increased.

  In other words, since the difference in the amount of received light between the presence and absence of liquid can be made more conspicuous, it can be used by expanding the range of specification conditions for the light emission efficiency of the light emitting element and the light receiving conversion efficiency of the light receiving element. Since the availability of the elements that can be increased and the power consumption for detection can be reduced, it is possible to more widely mount and easily use general electric devices.

  According to a third aspect of the present invention, there is provided a non-contact liquid detection configuration including a container body provided with a space for transmitting light and storing liquid therein, a light emitting element for irradiating light to the outside of the container body, and the light emission. A light receiving element that receives light emitted from the element and outputs an electrical signal corresponding to the amount of light received is disposed above the liquid surface, and the light emitting element is at an angle other than perpendicular to the surface of the container body. When the light is incident in the upward direction, the incident light causes total reflection on the liquid surface having a depth defined in the extending direction in which the liquid travels in a state where the liquid is present inside the container body, and The container body includes a reflecting surface that reflects so that the center of the traveling axis of the light whose traveling direction is changed by the total reflection is incident substantially perpendicular to the liquid surface, and the light receiving element is the reflecting surface. Light whose direction of travel has changed due to reflection As the arrangement for receiving, it may be configured as to determine that the liquid is in the interior of the container if the state increase in the amount of received light from a change of the electrical signal is determined to be the output of the light receiving element.

  That is, the light emitted from the light emitting element that is totally reflected on the liquid surface and then reflected on the reflecting surface when the liquid is at a prescribed depth inside the container body is received by the light receiving element, and the output of the light receiving element When the increase in the amount of received light can be determined from the change in the electrical signal, the state in which the liquid is present is determined.

  As a result, in a state where there is a liquid inside, the light transmitted through the liquid surface by reflection on the reflecting surface is incident substantially perpendicularly, so that the reflection to the inside of the liquid is minimized and the decrease in the amount of transmitted light is suppressed. It is possible to increase the amount of light received in a state where there is a liquid in a state where there is no liquid.

  In other words, the difference in the amount of received light between the state without liquid and the state with liquid can be made more prominent. Since the availability of the elements that can be increased and the power consumption for detection can be reduced, it is possible to more widely mount and easily use general electric devices.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 and FIG. 2 are cross-sectional views showing a part of a container for storing a liquid to be mounted on a device in an enlarged manner from the side. This container is provided with a space inside a container body 1 constituting an outer shell. It is configured so that the liquid 2 to be detected for use in equipment can be stored in the space.

  The to-be-detected liquid 2 stored in the container body 1 is pulled downward by gravity in the drawing, so that the upper portion is filled with air as the space portion 3.

  Here, the liquid to be detected 2 is a transparent body, for example, water, and in the following description, the case where the liquid to be detected 2 is water will be described as an example.

  An example of a device that uses water as the liquid to be detected 2 is a humidifier.

  If the equipment to be mounted is, for example, this humidifier, the container body 1 hits a tank for storing water for humidification or a tray having an open shape for evaporating water to generate humidified air. In general, it is configured to be removable from the main body, so that a user can supply water to the tank and clean the tray.

  Here, the container body 1 is made of a material that is light transmissive and has an absolute refractive index larger than that of air and equal to or higher than that of the liquid 2 to be detected.

  Therefore, since the container body 1 has an absolute refractive index of about 1.33 when the liquid 2 to be detected is water, it has excellent light transmittance and is hardly violated by water (absolute refractive index: about 1.5). Blow molding or gold with a thickness of about 0.5 mm to about 2 mm using resin materials such as polyethylene terephthalate (absolute refractive index: about 1.6) and polystyrene (absolute refractive index: about 1.6) It is formed by mold forming.

  When there is no liquid to be detected 2 inside the container body 1, the absolute refractive index of the space portion 3 is approximately 1 because it is filled with general air in the same way as around the device.

  Since the container body 1 also refracts light at the interface with the surrounding air and the liquid 2 to be detected due to the absolute refractive index provided in the constituent material, it is necessary to consider this refraction situation in an actual configuration. However, since it does not affect the gist of the description of the present embodiment, the following description will be omitted based on only the relationship between the liquid to be detected 2 and air.

  The light emitting element 4 that emits light to the outside of the container body 1 and the light receiving element 5 that receives the light emitted by the light emitting element 4 and outputs an electrical signal corresponding to the amount of the received light It arrange | positions so that a surface may oppose.

  The light emitting element 4 is arranged so that the light to be irradiated is incident at an angle other than perpendicular to the surface of the container body 1, and the light receiving element 5 is light in the extending direction in which the light incident on the container body 1 travels. Is arranged to receive light.

  From this, the light emitting element 4 and the light receiving element 5 are arranged in a state in which, for example, the corners of the container body 1 are sandwiched diagonally as shown in the figure.

  In addition, since the positions of the light emitting element 4 and the light receiving element 5 with respect to the container body 1 must be fixed for stable liquid detection, for example, an attachment site is provided on the container body 1 itself. It is necessary to fix.

  However, for example, if the equipment to be mounted is a humidifier shown as an example, it is necessary to adopt a configuration in which the container body 1 is fixed on the equipment side in consideration of the fact that the container body 1 is removed from the equipment body and used.

  At this time, if the outer shell forming the main body of the device is formed of an insulating resin, an attachment site is provided in a part of the configuration, and the container body 1 is fixed by being fixed to this site. In a state where the device is mounted at a specified position, the specified positional relationship can be maintained.

  FIG. 1 shows a state in which the container body 1 is mounted on a prescribed part of the main body of the device in this way, and the light emitting element 4 and the light receiving element 5 are 2 at the prescribed positions of the outer body 6 constituting the outer body of the main body of the device. An arrangement is shown in which an insertion hole 7 for fixing is provided at a location, and a predetermined positional relationship is maintained by mounting in the insertion hole 7.

  In addition, the insertion hole 7 in which the light-emitting element 4 and the light-receiving element 5 are mounted is covered with a protective sheet 8 made of a light-transmitting material by adhering it to the surface of the outer body 6 with an adhesive, thereby preventing the entry of dust or liquid. It is preventing.

  Here, the material of the protective sheet 8 is transparent and excellent in transparency with respect to the wavelength of light irradiated by the light receiving element 5, and is preferably a tough sheet-like sheet. A sheet material having a thickness of 7 mm is cut by a mold, and is fixed by adhering to the outer shell 6 having a configuration of detection using an acrylic adhesive.

  Further, it is important that the incident surface of the light irradiated by the light emitting element 4 and the transmission surface of the incident light to the light receiving element 5 in the container body 1 do not cause dispersion or convergence of light. Since the surface needs to be a smooth surface without irregularities, it is desirable to flatten the container body 1 even if the container body 1 has a shape such as a cylinder or a spherical surface.

  Here, the light emitting element 4 is preferably light other than visible light that does not bother the user because the light to be emitted is not intended for display or notification of the state of the device, and is obtained at a relatively low cost. Since an element with high property is desirable, for example, an infrared LED that emits infrared light having a wavelength of around 900 nm by using a direct current generally used in a remote control device is used.

  Here, the light receiving element 5 receives infrared light emitted from the light emitting element 4 and outputs an electric signal corresponding to the amount of received light. A resin in which a phototransistor element whose conduction current changes in accordance with the amount of received light is used in a resin having optical filter performance for attenuating light.

  If the light receiving element 5 is based on the above-described phototransistor element, for example, if a direct current power source and a resistance element are connected in series, the light receiving element 5 corresponds to the amount of light received according to the characteristics of the light receiving element 5. The conduction current flows through the resistance element using the DC power source as a power source, and a voltage proportional to the conduction current is generated at both ends of the resistance element.

  Therefore, the voltage generated at both ends of the resistance element changes in accordance with the amount of received light, and this change in voltage is read as an electric signal in accordance with the amount of received light by, for example, a one-chip microcomputer having an A / D conversion function. If the configuration is used, the change in the amount of received light can be recognized by software processing from the change in the electrical signal, and further, the presence or absence of liquid can be determined from the change in the amount of received light.

  By the way, it is known that the angle of refraction of light can be obtained by the following formula 1 based on the absolute refractive index and the incident angle of the medium before and after light is transmitted by the law of refraction.

sin i / sin r ≈ nb / na (Equation 1)
In the above formula, i is an incident angle of light with respect to a normal line perpendicular to the light incident interface, r is a refraction angle with respect to the normal line after incidence, na is an absolute refractive index of light on the incident side, and nb is after incidence. It can be seen that the relationship between the incident angle and the refraction angle of the light of the medium is constant in proportion to the ratio of the absolute refractive index of the medium before and after the incidence.

  Therefore, when the light emitted from the light emitting element 4 is incident at an angle other than perpendicular to the surface of the container body 1, there is no liquid to be detected 2 inside the container body 1 except for the influence of the constituent material of the container body 1. Sometimes the space 3 inside and around the container body 1 is occupied by air and has the same absolute refractive index, so that the light does not refract and is incident as shown by the dotted arrow line in the figure. It will proceed in the direction.

  When the liquid to be detected 2 is present inside the container body 1, the absolute refractive index of the liquid to be detected 2 is large relative to the air around the container body 1, so that the light is indicated by solid arrows in the figure. It can be seen that as the angle of incidence with respect to the normal line is refracted and the incident angle is larger, the change width of the refraction angle with respect to the incident angle becomes larger.

  For example, if the liquid to be detected 2 is water, the absolute refractive index is about 1.33 and the air is about 1 as described above. Therefore, if the incident angle is 30 °, the refraction angle is about 22 °. If the incident angle is about 60 °, the refraction angle will be narrowed to about 41 ° and −19 °.

  By the way, as described above, if the light-emitting element 4 and the light-receiving element 5 are general infrared LEDs and phototransistor elements having excellent availability, there is a spread of at least ± 15 ° in the range of light irradiation and light reception.

  Therefore, in determining the presence / absence of liquid based on the difference in refraction angle depending on the presence / absence of the liquid 2 to be detected, if the arrangement of the light emitting element 4 is set so that the incident angle of light is larger, the change width of the refraction angle Will grow.

  As a result, the amount of change in the amount of light received depending on the presence or absence of the liquid to be detected 2 increases in the direction of the light receiving element 5 in which the light travels, and accordingly, the difference in the electrical signal output from the light receiving element 5 is further clarified. Thus, it can be understood that it is advantageous in detection detection.

  However, the light incident obliquely on the surface of the container body 1 has an incident angle that increases as the incident angle increases according to the law of reflection and the Fresnel equation represented by the following equations 2 and 3. It is known that the proportion of light reflected in the opposite direction of incidence at the same angle increases.

rp = [cosi − ((nb / na) ^ 2− (sini) ^ 2) ^ 0.5] / [cosi + ((nb / na) ^ 2− (sini) ^ 2) ^ 0.5] .... (Formula 2)
rs = [− cosi (nb / na) ^ 2 + ((nb / na) ^ 2 i (sini) ^ 2) ^ 0.5] / [cosi (nb / na) ^ 2 + ((nb / na) ^ 2− (sini) ^ 2) ^ 0.5] (Equation 3)
In the above formulas 2 and 3, i is an incident angle of light with respect to a normal line perpendicular to the light incident interface, na is an absolute refractive index of light on the incident side, and nb is an absolute refractive index of light of the medium after incident. , Rp and rs are the reflectivities of the P wave and S wave polarized waves, respectively.

  This indicates that the amount of light transmitted to the liquid to be detected 2 required for detecting the liquid is reduced, and in the configuration for determining the presence or absence of the liquid to be detected from the difference in the amount of light received by the light receiving element 5. This leads to an increased possibility that it is necessary to use the light-emitting element 4 and the light-receiving element 5 with higher efficiency and higher sensitivity and to increase the power for light irradiation for stable detection.

  When light travels from water with an absolute reflectance of 1 to water or resin of about 1.3 to 1.6, according to the law of reflection, and according to Fresnel's formula, the incident angle with respect to the normal perpendicular to the incident interface If the angle is 60 ° or less, a total of about 75% or more is transmitted.

  Therefore, when the influence of this reflection is taken into consideration, when the liquid 2 to be detected is water, an arrangement is made such that the central axis of the light range irradiated by the light emitting element 4 is an incident angle of 50 ° to 60 ° with respect to the container body 1. This is desirable for stable detection of liquid.

  For example, as shown in FIG. 3 as an example of the arrangement in the configuration of the present embodiment, if the incident angle of light with respect to the container body 1 is 55 °, the refraction angle in the liquid to be detected 2 is about 38. Therefore, the light incident on the container body 1 travels by being refracted by 17 ° when there is no liquid to be detected 2 inside.

  If the light receiving element 5 is arranged in the extending direction in which either light before and after refraction travels, the presence or absence of the liquid 2 to be detected is determined from the difference in the value of the electric signal output from the light receiving element 5 according to the amount of light received. Will be able to.

  Here, if the light receiving element 5 is arranged in the extending direction in which the light before refraction travels, the amount of light received by the light receiving element 5 and the electric signal to be output are large when there is no liquid 2 to be detected, and small when there is. Change.

  Further, if the light receiving element 5 is arranged in the extending direction in which the light after refraction travels, the amount of light received by the light receiving element 5 and the electric signal to be output are large when the liquid 2 to be detected is present, and change in a small direction if there is not. It will be.

  Therefore, in the two arrangements of the light receiving elements 5, the value of the electric signal corresponding to the presence or absence of the liquid 2 to be detected output from the light receiving element 5 is measured in advance, for example, the intermediate value of each measured value is set as a threshold value in advance. If the magnitude relationship is compared with this threshold value, the presence or absence of the liquid to be detected 2 can be determined from the difference in the electrical signal.

  By the way, on the surface where light is transmitted from the inside of the container body 1 on the side where the light receiving element 5 is disposed to the outside, when light is incident obliquely with respect to the transmission surface based on the law of reflection and the Fresnel formula, Reflection in the inner direction of the container body 1 occurs on the surface, thereby reducing the amount of light transmitted.

  At this time, the light is transmitted from water or resin having an absolute reflectance of about 1.3 to 1.6 toward the air around the container body 1, and the liquid to be detected enters the inside of the container body 1. When there is 2, the light is reflected almost at one place on the outer surface of the container body 1, and when there is no liquid 2 to be detected inside the container body 1, the light is reflected at two places on the inner surface and the outer surface of the container body 1. Is reflected.

  Also, when light is transmitted from water or resin having an absolute reflectivity of about 1.3 to 1.6 in the direction of air having an absolute reflectivity of 1, incident on a normal normal to the entrance interface based on the law of refraction It is also known that when the angle is about 49 ° or more, light is totally reflected at the interface and is not transmitted.

  In the situation where all the traveling light is reflected in the inner direction of the container body 1 as in total reflection, the light receiving element 5 is placed outside the container body 1 in the extension direction in which the light before total reflection proceeds. Even if it is arranged, the light emitted from the light emitting element 4 does not reach the light receiving element 5, and the electrical signal output from the light receiving element 5 does not change depending on the presence or absence of liquid.

  For example, as shown in FIG. 1, in the configuration in which the corner portion of the container body 1 that is substantially perpendicular is sandwiched between the light emitting element 4 and the light receiving element 5, the incident angle of the light emitting element 4 is 55 ° as described above. In this case, if there is water as the liquid to be detected 2, the refraction angle is about 38 °, and the incident angle with respect to the normal perpendicular to the incident interface of the light transmitted from the inside of the container body 1 to the outside is about 52. °.

  Therefore, in the above configuration, when the liquid to be detected 2 is inside the container body 1, the incident angle in the light transmission direction from the inside of the container body 1 to the outside is about 49 ° or more, and thus total reflection occurs. As a result, light cannot be transmitted substantially.

  Therefore, in the configuration in which the light receiving element 5 is arranged outside the container body 1 in the extending direction in which the light refracted by the liquid to be detected 2 travels, the amount of light received does not change depending on the presence or absence of the liquid to be detected 2. In addition, it can be seen that the configuration for determining the presence of the liquid to be detected 2 by increasing the amount of received light does not actually function.

  In order to prevent the occurrence of total reflection, the incident angle of light with respect to the container body 1 of the light emitting element 4 is set to about 61 ° or more so that the light refraction angle in the state where the liquid 2 is detected is set to 41 ° or more. The incident angle of the light in the transmission direction from the inside of the container body 1 to the outside needs to be configured to be about 49 ° or less.

  However, as described above, when light is incident obliquely on the surface of the container body 1, the greater the incident angle, the greater the proportion of light reflected in the opposite direction and the light transmitted through the container body 1. Since the amount of light is reduced, it is desirable that the incident angle be 60 ° or less. Therefore, the incident angle in the light transmission direction from the inside of the container body 1 to the outside is set to 49 ° or less, which is further narrowed. That will be difficult.

  Thus, since it is difficult to adjust the incident angle in the light transmission direction from the inside to the outside of the container body 1 to an angle close to 49 ° at which total reflection occurs, even if the state of total reflection can be prevented, Since most of the light is reflected from the inside of the container body 1 toward the inside of the container body 1 and part of the light is transmitted to the outside of the container body 1, it depends on the presence or absence of the liquid 2 to be detected. The difference in the amount of light received by the light receiving element 5 becomes very small.

  However, in the method of determining the presence or absence of the liquid to be detected 2 from the difference in the amount of light received by the light receiving element 5 depending on the presence or absence of the liquid to be detected 2, the difference becomes clearer as the difference in the amount of light received by the light receiving element 5 increases. This is advantageous for determining the presence or absence of the liquid 2 to be detected, and makes it possible to determine the presence or absence of a more stable liquid.

  Therefore, in consideration of the decrease in the amount of transmitted light, a light emitting element 4 having a high light emission efficiency is used, the light emission intensity is increased by increasing the applied power, or the light receiving element 5 has a high light receiving conversion efficiency. It was common to take measures such as using.

  By the way, in general, when light is perpendicularly incident on the interface of a medium having a different absolute refractive index, the light is generally reflected according to the reflectance R obtained by the following equation 4 based on the law of reflection. Are known.

R = (na−nb) ^ 2 / (na + nb) ^ 2 (Equation 4)
In the above equation 4, na is the absolute refractive index of light on the incident side, and nb is the absolute refractive index of light in the medium after incidence.

  Therefore, for example, when light is incident perpendicularly to the interface in the direction of air having an absolute reflectivity of 1 from water or resin having an absolute reflectivity of about 1.3 to 1.6, it is about 3.4% of the total. Only the remaining 96% or more is transmitted in the direction of the space.

  From this, it can be seen that the incident light can be transmitted without being substantially attenuated by arranging the light transmitting surface as a plane and perpendicular to the light traveling axis.

  Therefore, in this configuration, the light transmitting flat surface portion 9 having a planar shape that is substantially perpendicular to the light traveling axis is provided on the surface through which light is transmitted from the inside of the container body 1 on the side where the light receiving element 5 is disposed. By providing, almost all of the light traveling inside the container body 1 can be received by the light receiving element 5.

  Here, FIG. 1 shows a configuration in which the light receiving element 5 is arranged in the extending direction in which the light after refraction travels, and if the amount of light received by the light receiving element 5 increases, it is determined that the liquid to be detected 2 is present. FIG. 2 shows a configuration in which the light receiving element 5 is arranged in the extending direction in which the light before refraction travels and it is determined that there is no liquid to be detected 2 if the amount of light received by the light receiving element 5 decreases.

  In addition, the light transmission flat part 9 is formed by projecting a position portion of the container body 1 by simultaneous molding in blow molding or mold molding when the container body 1 is manufactured, for example.

  In the above-described configuration, the light emitting element 4 that causes light to enter the outside of the container body 1 that stores the transparent liquid to be detected 2 made of a light transmissive material at an angle other than perpendicular to the surface of the container body 1, The light emitting element 4 for receiving the light transmitted through the container body 1 in the extending direction after the light irradiated by the light emitting element 4 is refracted in the presence or absence of the liquid 2 to be detected or in the state before the refraction is formed on the container body 1. The surface of the container body 1 on the side where the light receiving element 5 is disposed is arranged to face each other with a corner portion interposed therebetween, and the surface that transmits light from the inside to the outside has a planar shape that is substantially perpendicular to the light traveling axis. A light transmission plane portion 9 is provided, and the presence or absence of the liquid to be detected 2 is determined by comparing an electric signal output from the light receiving element 5 according to the amount of light received with a predetermined value.

  For this reason, on the surface that transmits light from the inside of the container body 1 to the outside, the light transmitting flat surface portion 9 is arranged to suppress reflection in the inner direction of the light, and almost all of the light is transmitted. The element 5 can receive light.

  Therefore, the difference in the received light amount in a certain state with respect to the state in which the light receiving element is free of liquid and the difference in the received light amount in the non-state with respect to the state with the liquid in the light receiving element can be further increased. The availability of elements that can be used is increased by widening the range of specification conditions for the light emitting efficiency of the light emitting element 4 and the light receiving conversion efficiency of the light receiving element 5 with respect to the configuration in which the amount of transmitted light decreases in the transmission of light, and Since power consumption for detection can be reduced, it can be more widely installed and used for general electric devices.

  If the light receiving element 5 is arranged in the extending direction in which the light after refraction travels, the light receiving element 5 is covered even in a state where the amount of light transmitted due to adhesion of dust or dirt to the surface of the container body 1 with long-term use decreases. It is possible to determine that the detection liquid 2 is not present and agree.

  At this time, it goes without saying that a water-safe device such as a humidifier can be used for fail-safe operation, such as by urging the user to maintain the water supply or cleaning the device by stopping the operation of the mounted device. Yes.

  The container body 1 is made of a light-transmitting material. However, even if the container body 1 is made of a non-light-transmitting material such as metal, an opening is formed only in a portion that needs to transmit light. The opening is closed with a light-transmitting plate material, and is adhered to the container body 1 with an adhesive or welding so as not to leak the liquid 2 to be detected, or fixed by simultaneous molding. As a result, it is possible to detect the presence / absence of the liquid 2 to be detected, and there is no difference in the function and effect in this configuration.

  The container body 1 is not limited to any shape as long as it has an arrangement satisfying the relationship between the incident light from the light emitting element 4 and the light received by the light receiving element 5 described above, as shown in FIG. Even if the tank shape is covered in direction or the shape of a part of the conduit shown in FIG.

(Embodiment 2)
6 to 8, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 6 is a cross-sectional view showing a configuration of a side surface in an example of a container body 1 for storing a liquid mounted on an apparatus.

  The light emitting element 4 is disposed outside the container body 1 so that the light to be irradiated is incident upward on the surface of the container body 1 at an angle other than vertical.

  The light emitting element 4 is a space that becomes the surface of the liquid to be detected 2 having a predetermined depth in the extending direction in which the light incident on the inside of the container body 1 travels in a state where the liquid to be detected 2 is present inside the container body 1. As described above, light is incident at the same angle of incidence without transmitting in the direction of the upper space, as indicated by the law of reflection and the Fresnel equation, as described above. It arrange | positions with respect to the container body 1 so that the total reflection which advancing direction may change by reflecting in all the opposite directions may arise.

  The depth of the liquid to be detected 2 is a rectangular parallelepiped when the shape of the container body 1 is viewed from the side as shown in FIG. 6, and the light emitting element 4 is disposed on the side surface of the container body 1. This corresponds to the distance from the incident position of light to the container body 1 to the surface of the liquid 2 to be detected.

  On the extended line of the light whose traveling direction has changed due to total reflection, light is incident substantially perpendicular to the surface of the liquid to be detected 2, so that the surface of the liquid to be detected 2 is directed toward the liquid to be detected 2. By suppressing the occurrence of reflection, an inclined reflecting surface 10 is provided to guide and transmit light to the upper space 3 of the liquid 2 to be detected without causing any attenuation.

  Here, the inclination angle of the reflecting surface 10 is such that, as described above, light is reflected in the opposite direction of incidence at the same angle as the incident angle in total reflection, so that the total reflected light on the surface of the liquid 2 to be detected is reflected. If the light is inclined with respect to the surface of the liquid 2 to be detected at an angle that is half the incident angle, the light can be reflected so that the traveling axis of the light is incident substantially perpendicular to the surface of the liquid 2 to be detected. .

  The reflecting surface 10 is composed of a color or material having excellent reflectivity of white or silver light in order to reflect light efficiently. For example, the target surface of the container body 1 is formed in the shape of the reflecting surface 10. By forming the mold of the container body 1 to be raised, the reflective surface 10 is formed simultaneously with the container body 1 and a flat plate cut with a resin material such as white ABS is adhered to the surface of the reflective surface 10 later, or A highly light reflective coating such as a transparent acrylic resin in which metal powder such as aluminum is turbid is applied.

  The light receiving element 5 arranges the light receiving surface so as to receive light on an extension line in the traveling direction of the light whose traveling axis is changed so that the light is incident on the surface of the liquid 2 to be detected substantially perpendicularly by the reflecting surface 10. Is.

  Here, the position of the arrangement of the light emitting element 4 and the light receiving element 5 must be fixed with respect to the container body 1 for stable liquid detection, as described above. In the structure in which the body 1 is removed, and the outer body 6 constituting the main body of the device is formed of an insulating resin, the outer body 6 is fixed at two positions specified by the outer body 6. The point which comprises so that a predetermined | prescribed positional relationship may be maintained by providing and providing the insertion hole 7 does not change.

  Therefore, with the above configuration, if the liquid 2 to be detected is not inside the container body 1 or does not reach the specified depth, the light irradiated from the light emitting element 4 and incident on the container body 1 is totally reflected. Since the light travels while maintaining substantially the incident angle without being generated, it is not guided to the light receiving element 5 arranged to receive the light reflected by the reflecting surface 10.

  However, if the liquid to be detected 2 exists inside the container body 1, the light incident on the container body 1 is totally reflected on the surface of the liquid to be detected 2 and then reflected by the reflecting surface 10. Since the light is guided to the light receiving element 5 without causing attenuation due to transmission in the direction of the space 3 on the surface of the liquid 2, the light received from the light emitting element 4 is received by the light receiving element 5. It can be determined that the liquid 2 to be detected is present inside the container body 1.

  Next, as a specific example of the configuration, a specific example of the arrangement when the liquid 2 to be detected is water will be described with reference to FIG.

  FIG. 7 is a cross-sectional view showing a part of a container for storing a liquid to be mounted on a device in a simplified manner from the side.

  Here, as described above, the incident angle of light causing total reflection at the interface where the medium is different is defined by the absolute refractive index of the medium before and after the light is transmitted by the law of reflection and the Fresnel equation. If water is water, the absolute reflectance is about 1.33, and when light is transmitted in the direction of air where the absolute reflectance is about 1, the incident angle with respect to the normal perpendicular to the incident interface is about 49 ° or more. Light is totally reflected at the interface.

  Therefore, when the light emitting element 4 is arranged so that the incident angle of light with respect to the normal line perpendicular to the light incident interface with respect to the container body 1 is, for example, 55 °, the light incident into the container body 1 is detected liquid. Refracts at an angle of refraction of about 38 ° at the interface with 2 and proceeds.

  This refracted light is incident at an incident angle of about 52 ° with respect to the normal normal to the surface of the liquid 2 to be detected, and this angle is about 49 ° or more with respect to the incident interface. Thus, total reflection occurs.

  When total reflection occurs on the surface of the liquid 2 to be detected, the light is not transmitted in the direction of the space 3 above the liquid 2 to be detected, but is reflected at the same incident angle in the opposite incident direction. The direction of travel will change.

  Here, if the depth of the liquid 2 to be detected is defined to be 18 mm, for example, the light irradiated from the light emitting element 4 has a position of about 22 mm in the horizontal direction from the incident surface to the container body 1 due to the trigonometric function. Total reflection occurs at the center.

  Therefore, the angle of inclination of the reflecting surface 10 may be inclined by about 26 ° from the horizontal plane since the incident angle of light with respect to the surface of the liquid 2 to be detected is about 52 °.

  Here, the distance in the horizontal direction from the position where total reflection occurs on the surface of the liquid to be detected 2 of the light receiving element 5 is the liquid to be detected at the center of the optical axis of the light totally reflected with respect to the reflecting surface 10. If the depth from the surface of 2 is set to 20 mm, for example, it becomes about 26 mm from the relation of the trigonometric function.

  Therefore, the light receiving element 5 is disposed at a lateral position of about 48 mm from the incident surface of the light irradiated from the light emitting element 4 to the container body 1.

  Here, when there is no liquid 2 to be detected inside the container body 1, the light emitting element 4 is arranged so that the incident angle of light is 55 ° with respect to the container body 1. From the relationship, the center of the optical axis of the light that refracts the space inside the container body 1 is about 69 mm in the vertical direction from the incident position of the light to the container body 1 surrounded by a dotted circle in FIG. It intersects with the light receiving axis of the light receiving element 5 from an oblique direction at the position of the height.

  When the light receiving element 5 is disposed at the intersecting height, the light receiving element 5 receives the light emitted from the light emitting element 4 from an oblique direction in spite of the absence of the liquid 2 to be detected. Depending on the presence or absence of the liquid 2 to be detected, the difference in the amount of received light may be narrowed, making it difficult to determine the presence or absence of the liquid 2 to be detected.

  Further, as described above, since the light irradiation range of the light emitting element 4 and the light receiving range of the light receiving element 5 are spread at least around ± 15 °, the light emitting element 4 is irradiated in the absence of the liquid 2 to be detected. The possibility that the light is received by the light receiving element 5 is also affected by the element to be used, and is difficult to regulate, which similarly makes it difficult to determine the presence or absence of the liquid 2 to be detected.

  Therefore, in order to prevent the light receiving element 5 from receiving the light emitted from the light emitting element 4 in the absence of the liquid to be detected 2, the vertical arrangement position of the light receiving element 5 with respect to the incident position of the light on the container body 1 is The height is about 69 mm, for example, avoiding the height of about 69 mm, which is the intersection position shown in FIG.

  The height of the arrangement of the light receiving elements 5 is set to a height that does not affect the determination of the presence or absence of the liquid 2 to be detected while confirming the light receiving state of the light receiving elements 5 in the design of the actual configuration. is there.

  Further, the arrangement of the light receiving element 5 with respect to the container body 1 is configured such that the light receiving element 5 is attached to the insertion hole 7 provided in the outer body 6 constituting the main body of the device and is kept at a specified position. Since the incident light is blocked by the outer body 6 and the insertion hole 7 and hardly reaches the light receiving element 5, in consideration of this point in designing the actual configuration, the arrangement of the light receiving elements 5 is high. The height may be set to a height that does not affect the determination of the presence or absence of the liquid 2 to be detected.

  In the above configuration, when the liquid to be detected 2 has a predetermined depth inside the container body 1, the light irradiated from the light emitting element 4 and incident on the container body 1 is not attenuated on the surface of the liquid to be detected 2. The traveling axis is changed so that it is reflected and guided to the reflecting surface 10 and further reflected by the reflecting surface 10 and is incident on the surface of the liquid 2 to be detected substantially perpendicularly, and the light whose traveling axis is changed proceeds. Light is received by the light receiving element 5 on the extended line.

  At this time, in a state where the liquid to be detected 2 is inside the container body 1, the light transmitted from the surface of the liquid to be detected 2 toward the space in the direction of the light receiving element 5 is substantially perpendicular to the surface of the liquid to be detected 2. Since reflection does not occur at the interface between two media having different absolute refractive indexes due to incidence, the amount of transmitted light reaches the light receiving element 5 without decreasing.

  Therefore, the range of selection of the light emission efficiency of the light emitting element 4 and the light reception conversion efficiency of the light receiving element 5 can be expanded with respect to a configuration in which the amount of transmitted light is reduced in the transmission of light from the liquid to be detected 2 in the direction of the surrounding space. Since the specification conditions of the elements to be used can be relaxed and the availability is increased, and the power consumption for detection can be reduced, it is possible to install and use more widely in general electrical equipment. it can.

  If the outer surface of the container body 1 is provided with a plane parallel to the surface of the liquid 2 to be detected between the light receiving element 5, the reflecting surface 10 is similar to the transmission of light on the surface of the liquid 2 to be detected. The light reflected by the light passes through the container body 1 without being attenuated. Therefore, the container body 1 has a tank-shaped configuration with the upper direction covered as shown in FIG. However, there is no difference in the effect.

  The surface of the reflecting surface 10 is preferably a smooth surface, but it can also be a surface with fine irregularities that disperse and reflect light. Needless to say, the inclination of the reflecting surface 10 can be set to an arbitrary angle when obtained in the element 5.

  The container body 1 is made of a light-transmitting material. However, even if the container body 1 is made of a non-light-transmitting material such as metal, an opening is formed only in a portion that needs to transmit light. The opening is closed with a light-transmitting plate material, and is adhered to the container body 1 with an adhesive or welding so as not to leak the liquid 2 to be detected, or fixed by simultaneous molding. As a result, it is possible to detect the presence / absence of the liquid 2 to be detected, and there is no difference in the function and effect in this configuration.

  The non-contact liquid detection configuration according to the present invention relaxes the conditions for obtaining an element used for detection of a transparent liquid, and also enables power consumption for detection to be reduced. Therefore, it is useful as a non-contact liquid detection configuration for determining the presence or absence of water in a home humidifier or dehumidifier.

DESCRIPTION OF SYMBOLS 1 Container body 4 Light emitting element 5 Light receiving element 9 Light transmission plane part 10 Reflecting surface

Claims (3)

A container body provided with a space for transmitting light and storing liquid therein, a light emitting element for irradiating light from the outside of the container body, and light emitted from the light emitting element from the inside of the container body In a configuration provided with a light receiving element that is transmitted to the outside and outputs an electrical signal corresponding to the amount of light received, disposed outside the container body, the light emitting element has an angle other than perpendicular to the surface of the container body. The light receiving element is disposed at a position where the incident light arrives in a state where there is a liquid inside the container body and receives light in the extending direction of the center of the light traveling axis. The container body is provided with a light transmission plane portion having a planar shape that is substantially vertical when the center of the optical axis of the light to be received is transmitted from the inside of the container body to the outside. If liquid is in the container, there is liquid inside the container. Contactless liquid detection arrangement which is adapted to determine that. The light receiving element is in a position where light incident without liquid in the container body reaches, and is arranged to receive light in the extending direction of the center of the light traveling axis, and the container body receives the light. If the center of the optical axis of the light has a plane-shaped light transmission plane portion that is substantially vertical when transmitting from the inside of the container body to the outside, The non-contact liquid detection configuration according to claim 1, wherein it is determined that there is no liquid inside. A container body provided with a space for transmitting light and storing a liquid therein, a light emitting element for irradiating light to the outside of the container body, and receiving light emitted from the light emitting element, according to the amount of light received A light receiving element that outputs an electrical signal is disposed above the surface of the liquid, and the light emitting element is configured to emit light when the light is incident upward at an angle other than perpendicular to the surface of the container body. The incident light is arranged to cause total reflection on the surface of the liquid having a depth defined in the extending direction in which the liquid travels in a state where the liquid is present inside the container body. A reflecting surface that reflects the light so that the center of the changed traveling axis is incident on the liquid surface substantially perpendicularly; and the light receiving element receives the light that has been reflected by the reflecting surface and whose traveling direction has changed. The power output from the light receiving element Contactless liquid detection arrangement which is adapted to determine that the liquid is in the interior of the container if the state increase in the amount of received light is determined from the change of the signal.

Images