JP2017161424A - Optical component sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical component sensor capable of highly accurately detecting a predetermined component.SOLUTION: An optical component sensor 1 comprises: a detection light source 21 which emits detection light LD1; a reference light source 22 which emits reference light LR1; a detection light-receiving element 31 which receives reflection detection light LD2 which is at least a part of the detection light LD1 reflected by an object 2; a reference light-receiving element 32 which receives reflection reference light LR2 which is at least a part of the reference light LR1 reflected by the object 2; a distance measuring unit 75 which measures the distance to the object 2; a temperature and humidity detecting unit 85 which detects a temperature and humidity of a space 3; a correcting unit 90 which corrects a detection signal corresponding to the reflection detection light LD2 on the basis of an absolute humidity calculated on the basis of the temperature and humidity detected by the temperature and humidity detecting unit 85, the distance measured by the distance measuring unit 75, and an absorption coefficient; and a signal processing circuit 95 which detects a component contained in the object 2 on the basis of the detection signal corrected by the correcting unit 90 and a reference signal corresponding to the reflection reference light LR2.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an optical component sensor that detects a predetermined component using detection light and reference light.

  Conventionally, an infrared moisture meter that measures the amount of moisture using absorption of infrared rays by moisture is known (see, for example, Patent Document 1). In the infrared moisture meter described in Patent Document 1, the amount of moisture contained in the paper is based on the intensity of infrared light transmitted and scattered by the paper by irradiating the paper with infrared light in a plurality of different wavelength ranges. Is detected. In the infrared moisture meter, in order to reduce the influence of moisture (water vapor), the wavelength range of infrared light is adjusted by a filter.

Japanese Patent Laid-Open No. 5-118984

  The plurality of filters provided in the conventional infrared moisture meter include a filter that transmits infrared rays in a wavelength range that is absorbed by moisture, and an infrared ray in a wavelength range that is less likely to be absorbed by moisture and that is absorbed by water vapor. And a filter that passes through. At this time, the two filters are required to transmit infrared rays in a wavelength region in which the absorption rate due to moisture and the absorption rate due to water vapor are approximately the same.

  In general, a plurality of mass-produced filters have variations in wavelength characteristics (center wavelength, transmittance, half-value width, cutoff rate, etc.). Further, matching is required in consideration of not only the wavelength characteristics of the filter but also the infrared energy by multiplication with the wavelength characteristics of the lamp and the light receiving element. Therefore, it is very difficult to manufacture the moisture absorption rate and the water vapor absorption rate at the same level. In the case where the variation in characteristics of each part in manufacturing is allowed, the detection accuracy of the moisture amount is remarkably lowered.

  Accordingly, an object of the present invention is to provide an optical component sensor that can accurately detect a predetermined component.

  To achieve the above object, an optical component sensor according to an aspect of the present invention includes a first light source that emits detection light that includes an absorption wavelength due to a predetermined component, and a reference light that does not include the absorption wavelength due to the component. 2 light sources, a housing that houses the first light source and the second light source, and reflected detection light that is at least part of the detection light reflected by an object located outside the housing. A first light receiving element housed in the housing, and a second light receiving element housed in the housing that receives reflected reference light that is at least part of the reference light reflected by the object. A distance measuring unit for measuring a distance from the housing to the object, a temperature / humidity detecting unit for detecting temperature and humidity of a space between the housing and the object, and the temperature / humidity detecting unit. Based on detected temperature and humidity Based on the calculated absolute humidity, the distance measured by the distance measuring unit, and a predetermined first extinction coefficient, a detection signal corresponding to the reflected detection light output from the first light receiving element is obtained. The component included in the object is detected based on a correction unit to be corrected, a detection signal corrected by the correction unit, and a reference signal corresponding to the reflected reference light output from the second light receiving element. And a signal processing circuit.

  The optical component sensor according to the present invention can detect a predetermined component with high accuracy.

It is a schematic diagram which shows the structure and target object of the optical component sensor which concern on embodiment. It is a block diagram which shows the function structure of the optical component sensor which concerns on embodiment. It is a figure which shows an example of the optical path of the detection light of the optical component sensor which concerns on embodiment. It is a figure which shows an example of the optical path of the reference light of the optical component sensor which concerns on embodiment. It is a figure which shows the absorption spectrum of a water | moisture content and water vapor | steam. It is a figure which shows the spectrum of the detection light of the optical component sensor which concerns on embodiment, and reference light. It is a figure which shows the sensitivity characteristic of the light receiving element of the optical component sensor which concerns on embodiment. It is a figure which shows the transmission spectrum of the optical filter of the optical component sensor which concerns on embodiment. It is a schematic diagram which shows the measurement principle of the distance by the triangulation method which concerns on embodiment. It is a schematic diagram which shows the measurement principle of the distance by the triangulation method which concerns on the modification 1. It is a schematic diagram which shows the measurement principle of the distance by the optical time-of-flight ranging method which concerns on the modification 2.

  Below, the optical component sensor which concerns on embodiment of this invention is demonstrated in detail using drawing. Note that each of the embodiments described below shows a preferred specific example of the present invention. Therefore, numerical values, shapes, materials, components, arrangement and connection forms of components, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims showing the highest concept of the present invention are described as optional constituent elements.

  Each figure is a mimetic diagram and is not necessarily illustrated strictly. Therefore, for example, the scales and the like do not necessarily match in each drawing. Moreover, in each figure, the same code | symbol is attached | subjected about the substantially same structure, The overlapping description is abbreviate | omitted or simplified.

(Embodiment)
[Overview]
First, an outline of the optical component sensor according to the embodiment will be described.

  FIG. 1 is a diagram showing a configuration of an optical component sensor 1 and an object 2 according to the present embodiment. FIG. 2 is a block diagram showing a functional configuration of the optical component sensor 1 according to the present embodiment. 3A and 3B are diagrams showing examples of optical paths of detection light and reference light of the optical component sensor 1 according to the present embodiment, respectively. 3A and 3B show only typical optical paths of the detection light and the reference light, respectively.

  The optical component sensor 1 irradiates the object 2 with two lights having different wavelengths (detection light LD1 and reference light LR1), and receives light reflected by the object 2 (reflection detection light LD2 and reflection reference light LR2). By doing so, it is a non-contact optical component sensor that detects a component contained in the object 2. In the present embodiment, as shown in FIG. 1, the optical component sensor 1 detects moisture contained in the object 2 located at a position spaced apart from the space 3.

  The object 2 is, for example, clothing or the like when not particularly limited. For example, by attaching the optical component sensor 1 to a clothes dryer or the like, it is possible to check the drying condition of the clothes. Thereby, generation | occurrence | production of the pain of the clothing by drying too much can be suppressed.

  The space 3 is a space (free space) between the optical component sensor 1 and the object 2 and includes moisture (water vapor). The space 3 is an external space of the housing 10 of the optical component sensor 1.

  As shown in FIG. 1, the optical component sensor 1 includes a housing 10, a detection light source 21, a reference light source 22, a detection light receiving element 31, a reference light receiving element 32, an optical element 40, A detection lens 51, a reference lens 52, a detection filter 61, a reference filter 62, a detection aperture 71, and a reference aperture 72 are provided. As shown in FIG. 2, the optical component sensor 1 includes a distance measurement unit 75, a control circuit 80, a temperature / humidity detection unit 85, a correction unit 90, and a signal processing circuit 95.

  Below, each component of the optical component sensor 1 is demonstrated in detail.

[Case]
The housing 10 is a housing that houses the detection light source 21 and the reference light source 22. As shown in FIG. 1, the housing 10 further includes a detection light receiving element 31, a reference light receiving element 32, an optical element 40, a detection lens 51, a reference lens 52, a detection filter 61, and a reference filter 62. A detection aperture 71 and a reference aperture 72 are accommodated.

  The housing 10 is made of a light shielding material. Thereby, it can suppress that external light injects into the housing | casing 10. FIG. Specifically, the housing 10 has a light shielding property against light received by the detection light receiving element 31 and the reference light receiving element 32. More specifically, the housing 10 has a light blocking property with respect to the reflected detection light LD2 (detection light LD1) and the reflected reference light LR2 (reference light LR1), and is formed of, for example, a resin material or a metal material. .

  An opening is provided in the outer wall of the housing 10, and a detection lens 51 and a reference lens 52 are attached to the opening. Although not shown, an opening for emitting light emitted from the detection light source 21 and the reference light source 22 to the outside is provided on the outer wall of the housing 10.

[Light source for detection]
The detection light source 21 is an example of a first light source that emits detection light LD1 including an absorption wavelength of a predetermined component. Specifically, the detection light source 21 is a dispersed light source that emits detection light LD1 including an absorption wavelength due to moisture as a peak wavelength. As shown in FIG. 3A, the detection light LD1 emitted from the detection light source 21 is reflected by the optical element 40 and emitted to the outside of the housing 10.

  FIG. 4 is a diagram showing absorption spectra of moisture and water vapor. As shown in FIG. 4, moisture has absorption peaks at wavelengths of about 1450 nm and about 1900 nm. Water vapor has absorption peaks at wavelengths slightly lower than the absorption peak of moisture, specifically at wavelengths of about 1350 nm to 1400 nm and about 1800 nm to 1900 nm.

  FIG. 5 is a diagram illustrating spectra of detection light and reference light of the optical component sensor 1 according to the present embodiment. As shown in FIG. 5, the detection light LD1 is infrared light including 1450 nm, which is an absorption wavelength due to moisture, as a peak wavelength. As can be seen by comparing FIG. 4 and FIG. 5, the detection light LD1 includes a wavelength component that is absorbed not only by water but also by water vapor.

  The detection light source 21 is, for example, a light emitting element that emits infrared light having a spectrum indicated by a solid line in FIG. The light emitting element is, for example, an LED (Light Emitting Diode) element, but is not limited thereto. As the light emitting element, a semiconductor laser element or an organic EL (Electro Luminescence) element may be used.

  As shown in FIG. 1, the detection light source 21 is fixed at a predetermined position in the housing 10. In the present embodiment, the detection light source 21 is disposed so as to face the reference light receiving element 32 with the optical element 40 interposed therebetween.

[Reference light source]
The reference light source 22 is an example (dispersed light source) of a second light source that emits reference light LR1 that does not include an absorption wavelength due to a predetermined component. As shown in FIG. 5, the reference light LR1 does not include a wavelength of about 1450 nm that is an absorption wavelength due to moisture, but includes, for example, a wavelength of about 1300 nm different from the absorption wavelength as a peak wavelength. The reference light LR1 emitted from the reference light source 22 is reflected by the optical element 40 and emitted to the outside of the housing 10 as shown in FIG. 3B.

  Note that not including the absorption wavelength does not mean only not including the absorption wavelength at all. The reference light LR1 may include an absorption wavelength whose intensity is sufficiently smaller than the peak wavelength. For example, the reference light LR1 may include an absorption wavelength with an intensity smaller than the detection resolution.

  The reference light source 22 is, for example, a light emitting element that emits infrared light having a spectrum indicated by a broken line in FIG. That is, the reference light source 22 emits infrared light including a peak wavelength that is different from the peak wavelength of the infrared light emitted from the detection light source 21. The light emitting element is, for example, an LED element, but may be a semiconductor laser element or an organic EL element.

  The reference light source 22 is fixed to a predetermined position in the housing 10 as shown in FIG. In the present embodiment, the reference light source 22 is disposed so as to face the detection light receiving element 31 with the optical element 40 interposed therebetween.

[Light-receiving element for detection]
The detection light receiving element 31 is an example of a first light receiving element that receives the reflected detection light LD2 that is at least part of the detection light LD1 reflected by the object 2. The detection light receiving element 31 photoelectrically converts the received reflection detection light LD2 to generate a detection signal that is an electrical signal corresponding to the amount of received light (that is, intensity) of the reflection detection light LD2. The generated detection signal is output to the signal processing circuit 95. In the present embodiment, the detection signal is also output to the distance measuring unit 75 and used for measurement of the distance L to the object 2 (that is, distance measurement).

  The reflected detection light LD2 is light that is reflected by the object 2 from the detection light LD1. The peak wavelength of the reflected detection light LD2 is the same as the peak wavelength of the detection light LD1 (about 1450 nm).

  FIG. 6 is a diagram showing sensitivity characteristics of the light receiving element of the optical component sensor 1 according to the present embodiment. In the present embodiment, a light receiving element having the characteristics shown in FIG. 6 is used for each of the detection light receiving element 31 and the reference light receiving element 32.

  Specifically, as shown in FIG. 6, the light receiving sensitivity of the detection light receiving element 31 has a positive correlation with a wavelength in the range of 1000 nm to 1600 nm. The light receiving sensitivity of the detection light receiving element 31 is not limited to this, and may be, for example, a substantially constant sensitivity with respect to each wavelength.

  Thus, the detection light receiving element 31 has a sufficiently high light reception sensitivity with respect to the peak wavelength of the reflected detection light LD2 (detection light LD1). Therefore, the detection light receiving element 31 can receive the reflection detection light LD2 and generate an electrical signal (detection signal) corresponding to the amount of received light.

  The detection light receiving element 31 is accommodated in the housing 10. For example, the detection light receiving element 31 is fixed in the housing 10 so that the light receiving surface is positioned at the focal point of the detection lens 51.

  The detection light receiving element 31 is, for example, a photodiode, but is not limited thereto. For example, the detection light receiving element 31 may be a phototransistor or an image sensor. The detection light receiving element 31 and the reference light receiving element 32 may use different regions of one image sensor.

[Reference light receiving element]
The reference light receiving element 32 is an example of a second light receiving element that receives the reflected reference light LR2 that is at least a part of the reference light LR1 reflected by the object 2. The reference light receiving element 32 photoelectrically converts the received reflected reference light LR2 to generate a reference signal that is an electrical signal corresponding to the amount of light received by the reflected reference light LR2. The generated reference signal is output to the signal processing circuit 95. In the present embodiment, the reference signal is also output to the distance measuring unit 75 and used for distance measurement.

  The reflected reference light LR2 is light obtained by reflecting the reference light LR1 by the object 2. The peak wavelength of the reflected reference light LR2 is the same as the peak wavelength (about 1300 nm) of the reference light LR1.

  The light receiving sensitivity of the reference light receiving element 32 has the characteristics shown in FIG. That is, the reference light receiving element 32 has sufficiently high light receiving sensitivity with respect to the peak wavelength of the reflected reference light LR2 (reference light LR1). Therefore, the reference light receiving element 32 can receive the reflected reference light LR2 and generate an electrical signal (reference signal) corresponding to each received light amount.

  The reference light receiving element 32 is accommodated in the housing 10. For example, the reference light receiving element 32 is fixed in the housing 10 so that the light receiving surface is located at the focal point of the reference lens 52.

  The reference light receiving element 32 is, for example, a photodiode, but is not limited thereto. For example, the reference light receiving element 32 may be a phototransistor or an image sensor.

[Optical element]
The optical element 40 emits the detection light LD1 and the reference light LR1 from the housing 10 toward the object 2 in the same spot size. The optical element 40 has, for example, a concave reflection surface, and the detection light LD1 and the reference light LR1 are reflected by the reflection surface. The detection light LD1 and the reference light LR1 are reflected at the same light distribution angle in the same direction by the reflection surface of the optical element 40, for example.

  Each of the detection light LD1 and the reference light LR1 reflected by the optical element 40 is emitted toward the object 2 located outside the housing 10. As shown in FIGS. 3A and 3B, the detection light LD1 and the reference light LR1 emitted to the outside of the housing 10 are applied to substantially the same portion of the object 2 with approximately the same spot size.

  The optical element 40 is formed, for example, by depositing a metal thin film by a vapor deposition method or the like on a resin molded body formed into a predetermined shape having a concave surface.

[Detection lens]
The detection lens 51 is a condensing lens for condensing the reflected detection light LD <b> 2 reflected by the object 2 onto the detection light receiving element 31. For example, the detection lens 51 is fixed to the housing 10 so that the focal point is located on the light receiving surface of the detection light receiving element 31. The detection lens 51 is, for example, a resin convex lens, but is not limited thereto.

[Reference lens]
The reference lens 52 is a condensing lens for condensing the reflected reference light LR <b> 2 reflected by the object 2 on the reference light receiving element 32. For example, the reference lens 52 is fixed to the housing 10 so that the focal point is located on the light receiving surface of the reference light receiving element 32. The reference lens 52 is, for example, a resin convex lens, but is not limited thereto.

[Detection filter]
The detection filter 61 is an example of a first filter provided on the optical path of the reflected detection light LD2 incident on the detection light receiving element 31. In the present embodiment, as shown in FIG. 1, the detection filter 61 is disposed between the detection lens 51 and the detection aperture 71. The detection filter 61 transmits the reflected detection light LD2 and absorbs the reflected reference light LR3. Therefore, as shown in FIG. 3B, the reflected reference light LR3 is absorbed by the detection filter 61 and hardly reaches the detection light receiving element 31.

  FIG. 7 is a diagram showing a transmission spectrum of the optical filter according to the present embodiment. As shown in FIG. 7, the detection filter 61 transmits 1450 nm light, which is the peak wavelength of the reflected detection light LD2, and absorbs light of 1300 nm, which is the peak wavelength of the reflected reference light LR3. The detection filter 61 may transmit a part of 1300 nm light. That is, the detection filter 61 may transmit the reflected reference light LR3 with a transmission amount smaller than the transmission amount of the reflected detection light LD2.

[Filter for reference]
The reference filter 62 is an example of a second filter provided on the optical path of the reflected reference light LR2 incident on the reference light receiving element 32. In the present embodiment, as shown in FIG. 1, the reference filter 62 is disposed between the reference lens 52 and the reference aperture 72. The reference filter 62 transmits the reflected reference light LR2 and absorbs the reflected detection light LD3. Therefore, as shown in FIG. 3A, the reflection detection light LD3 is absorbed by the reference filter 62 and hardly reaches the reference light receiving element 32.

  As shown in FIG. 7, the reference filter 62 transmits 1300 nm light, which is the peak wavelength of the reflected reference light LR2, and absorbs 1450 nm light, which is the peak wavelength of the reflected detection light LD3. Note that the reference filter 62 may transmit a part of light of 1450 nm. That is, the reference filter 62 may transmit the reflected detection light LD3 with a transmission amount smaller than the transmission amount of the reflected reference light LR2.

[Detection aperture]
The detection aperture 71 is an example of a first aperture that is provided in front of the light receiving surface of the detection light receiving element 31 and shields a part of the reflection detection light LD2 according to the incident angle of the reflection detection light LD2. For example, the detection aperture 71 is a light-shielding member provided with an opening (slit) having a predetermined diameter. The detection aperture 71 shields more reflected detection light LD2 as the incident angle of the reflected detection light LD2 is larger. Accordingly, the amount of the reflected detection light LD2 that passes through the detection aperture 71 is reduced, so that the amount of light received by the detection light receiving element 31 is reduced.

  The detection aperture 71 is a member used to measure the distance L to the object 2. Therefore, when the distance measurement using the detection signal is not performed, the detection aperture 71 may not be provided. The same applies to the reference aperture 72. Details will be described in Modifications 1 and 2.

[Reference Aperture]
The reference aperture 72 is an example of a second aperture that is provided in front of the light receiving surface of the reference light receiving element 32 and shields a part of the reflected reference light LR2 according to the incident angle of the reflected reference light LR2. For example, the reference aperture 72 is a light-shielding member provided with an opening (slit) having a predetermined diameter. The reference aperture 72 shields the reflected reference light LR2 more as the incident angle of the reflected reference light LR2 is larger. Accordingly, the amount of the reflected reference light LR2 that passes through the reference aperture 72 is reduced, so that the amount of light received by the reference light receiving element 32 is reduced.

[Rangefinder]
The distance measuring unit 75 measures a distance L from the housing 10 to the object 2. In the present embodiment, the distance measuring unit 75 measures the distance L by a triangulation method.

  FIG. 8 is a schematic diagram showing the principle of distance measurement by the triangulation method according to the present embodiment. Here, a case where the distance is measured using the reference light emitted from the reference light source 22 will be described. For simplicity of explanation, other members such as the optical element 40 are not shown.

  FIG. 8 shows an object 2a having a short distance from the reference light source 22 and the reference light receiving element 32 and an object 2b having a long distance. The reference light LRa1 emitted from the reference light source 22 is reflected by the object 2a, and the reflected reference light LRa2 that is the reflected light passes through the reference lens 52 and the reference aperture 72 to the reference light receiving element 32. Incident. Similarly, the reference light LRb1 emitted from the reference light source 22 is reflected by the object 2b, and the reflected reference light LRb2 that is the reflected light passes through the reference lens 52 and the reference aperture 72 and is received for reference. Incident on the element 32.

  As shown in FIG. 8, the reflected reference light LRa2 is incident on the light receiving surface of the reference light receiving element 32 at a large incident angle (at a shallow angle). For this reason, the amount of light (vignetting) that is shielded when passing through the reference aperture 72 increases. Therefore, the amount of the reflected reference light LRa2 incident on the reference light receiving element 32 is small.

  On the other hand, the reflected reference light LRb2 is incident on the light receiving surface of the reference light receiving element 32 at a small incident angle (from a direction perpendicular to the light receiving surface). For this reason, since the light quantity shielded by the reference aperture 72 is reduced, the light quantity of the reflected reference light LRb2 incident on the reference light receiving element 32 is large.

  Thus, by providing the reference aperture 72, the amount of received reflected reference light LR2 incident on the reference light receiving element 32 changes according to the incident angle of the reflected reference light LR2. As shown in FIG. 8, the incident angle of the reflected reference light LR <b> 2 depends on the distance L to the object 2. Specifically, the greater the distance L to the object 2 (for example, in the case of the object 2b), the smaller the incident angle of the reflected reference light LR2, and the greater the amount of received light. The smaller the distance L to the object 2 (for example, in the case of the object 2a), the larger the incident angle of the reflected reference light LR2 and the smaller the amount of received light. Therefore, the distance measuring unit 75 can measure the distance L to the object 2 based on the intensity (voltage level) of the reference signal output from the reference light receiving element 32.

  Actually, since the reference light LR1 and the reflected reference light LR2 are absorbed by the water vapor contained in the space 3, the intensity of the reference signal also changes according to the amount of water vapor. Therefore, in the present embodiment, the distance measuring unit 75 measures the distance L based on the ratio of the detection signal and the reference signal. Specifically, as shown in FIG. 1, by providing a similar detection aperture 71 in front of the detection light receiving element 31, the detection signal is also used for measuring the distance L.

  For example, the output change rate of the reference signal (or detection signal) due to the difference in incident angle is measured in advance in an environment that is not affected by moisture. As shown in FIG. 2, the distance measuring unit 75 stores an output change parameter 76 indicating the measured output change rate. For example, the distance measuring unit 75 has a storage unit such as a nonvolatile memory, and stores an output change parameter 76.

  The distance measuring unit 75 is composed of, for example, a microcontroller. The distance measuring unit 75 includes a non-volatile memory in which a distance measuring program and an output change parameter 76 are stored, a volatile memory that is a temporary storage area for executing the program, an input / output port, a processor that executes the program, and the like. Have. Note that the distance measurement unit 75, the control circuit 80, the correction unit 90, the signal processing circuit 95, and the like may be realized by each dedicated microcontroller, or may be realized by one microcontroller.

[Control circuit]
The control circuit 80 individually controls the light emission of the detection light source 21 and the light emission of the reference light source 22. Specifically, the control circuit 80 can independently control the light emission and extinction of the detection light source 21 and the light emission and extinction of the reference light source 22.

  For example, the control circuit 80 causes the detection light source 21 and the reference light source 22 to emit light exclusively in time. That is, the light emission period of the detection light source 21 and the light emission period of the reference light source 22 do not overlap. Specifically, the control circuit 80 causes the detection light source 21 and the reference light source 22 to repeatedly emit light alternately and exclusively in time. For example, the control circuit 80 outputs a pulse signal having a predetermined frequency (for example, 1 kHz) to the detection light source 21 and the reference light source 22. The pulse signal output to the detection light source 21 and the pulse signal output to the reference light source 22 are synchronized so that the respective pulses do not overlap.

  For example, the pulse signal of the detection light source 21 is a pulse signal having an on-duty ratio of 50% or less. The pulse signal of the reference light source 22 is a pulse signal obtained by shifting the phase of the pulse signal of the detection light source 21 by 180 degrees. Thereby, the light emission period of the detection light source 21 and the light emission period of the reference light source 22 can be made to have the same length and not overlap each other.

  Although not shown in FIG. 1, the control circuit 80 may be housed in the housing 10 or attached to the outer surface of the housing 10. Alternatively, the control circuit 80 may have a communication function such as wireless communication, and may transmit a control pulse signal to the detection light source 21 and the reference light source 22.

  The control circuit 80 is composed of, for example, a drive circuit and a microcontroller. The control circuit 80 includes a nonvolatile memory in which a light source control program is stored, a volatile memory that is a temporary storage area for executing the program, an input / output port, and a processor that executes the program.

[Temperature and humidity detector]
The temperature / humidity detector 85 is a temperature / humidity sensor that detects the temperature and humidity of the space 3. In the present embodiment, the temperature / humidity detection unit 85 calculates the absolute humidity of the space 3 using the detected temperature and humidity. Absolute humidity is the amount of water vapor per unit volume contained in the space 3. The absolute humidity calculated by the temperature / humidity detection unit 85 is output to the correction unit 90.

  The temperature / humidity detection unit 85 is attached to the outer surface of the housing 10, for example. Alternatively, the temperature / humidity detection unit 85 may be separate from the housing 10 or may be provided at a predetermined position in the space 3. In this case, the temperature / humidity detection unit 85 and the correction unit 90 (or the signal processing circuit 95 or the like) have a wireless communication function, and may transmit and receive absolute humidity wirelessly.

[Correction section]
The correction unit 90 corrects the detection signal based on the absolute humidity of the space 3, the distance L, and a predetermined extinction coefficient αc1 for detection light. The detection light LD1 and the reflection detection light LD2 include wavelength components that are absorbed by water vapor (humidity) contained in the space 3. Therefore, the detection signal is a signal that is affected not only by absorption by moisture contained in the object 2 but also by absorption by water vapor. Therefore, the correction unit 90 corrects the detection signal so as to cancel the absorption due to water vapor.

  In the present embodiment, the correction unit 90 further corrects the detection signal based on the absolute humidity of the space 3, the distance L, and a predetermined extinction coefficient αc2 for reference light. The reference light LR <b> 1 and the reflected reference light LR <b> 2 include wavelength components that are absorbed by water vapor contained in the space 3. Therefore, the reference signal is a signal that is affected not only by absorption by moisture contained in the object 2 but also by absorption by water vapor. For this reason, the correction unit 90 corrects the reference signal so as to cancel the absorption due to water vapor.

  Details of correction of the detection signal and the reference signal by the correction unit 90 will be described later.

  When the absorption of the reference light LR1 and the reflected reference light LR2 by water vapor is sufficiently small, the correction unit 90 does not have to correct the reference signal.

  The correction unit 90 is configured by a microcontroller, for example. The correction unit 90 includes a nonvolatile memory in which a correction program is stored, a volatile memory that is a temporary storage area for executing the program, an input / output port, a processor that executes the program, and the like.

[Signal processing circuit]
Based on the detection signal corresponding to the reflected detection light LD2 output from the detection light receiving element 31 and the reference signal corresponding to the reflected reference light LR2 output from the reference light receiving element 32, the signal processing circuit 95 A component contained in the object 2 is detected. Specifically, the signal processing circuit 95 detects the amount of moisture contained in the object 2 based on the ratio (energy ratio) between the voltage level of the detection signal and the voltage level of the reference signal.

  In the present embodiment, the signal processing circuit 95 detects the amount of water contained in the object 2 based on the detection signal corrected by the correction unit 90 and the corrected reference signal. A specific moisture amount detection (calculation) method will be described later.

  The signal processing circuit 95 may be accommodated in the housing 10 or attached to the outer surface of the housing 10. Alternatively, the signal processing circuit 95 may have a communication function such as wireless communication, and may receive output signals from the detection light receiving element 31 and the reference light receiving element 32.

  The signal processing circuit 95 is, for example, a microcontroller. The signal processing circuit 95 includes a nonvolatile memory in which a signal processing program is stored, a volatile memory that is a temporary storage area for executing the program, an input / output port, a processor that executes the program, and the like.

[Signal processing (detection processing)]
Next, signal processing (component detection processing) by the correction unit 90 and the signal processing circuit 95 will be described.

  In the present embodiment, the signal processing circuit 95 detects the amount of components contained in the target object 2 by comparing the light energy Pd of the reflected detection light LD2 and the light energy Pr of the reflected reference light LR2. The light energy Pd corresponds to the intensity of the detection signal output from the detection light receiving element 31, and the light energy Pr corresponds to the intensity of the reference signal output from the reference light receiving element 32.

  The light energy Pd of the reflected detection light LD2 incident on the detection light receiving element 31 is expressed by the following (Equation 1).

  (Formula 1) Pd = Pd0 × Gd × Rd × Td × Acd × Aad × Ivd

  Here, Pd0 is the light energy of the detection light LD1 emitted by the detection light source 21. Gd is the coupling efficiency (condensing rate) of the detection light LD1 emitted from the detection light source 21 to the detection light receiving element 31. Specifically, Gd corresponds to a ratio of a part of the detection light LD1 that becomes a part of the component diffusely reflected by the object 2 (that is, the reflection detection light LD2).

  Rd is the reflectance of the detection light LD1 by the object 2. Td is the transmittance of the reflected detection light LD2 by the detection filter 61. Ivd is the light receiving sensitivity of the detection light receiving element 31 with respect to the reflected detection light LD2.

  Acd is the absorptance of the detection light LD1 and the reflection detection light LD2 by the water vapor contained in the space 3, and is expressed by the following (Expression 2).

(Formula 2) Acd = 10 ^{−αc1 × Cc × 2L}

  Here, αc1 is a predetermined first extinction coefficient, specifically, a converted extinction coefficient in the wavelength region of the detection light LD1 and the reflected detection light LD2. In the present embodiment, αc1 is determined in advance based on the emission intensity distribution with respect to the wavelength of the detection light LD1 emitted by the detection light source 21, the sensitivity characteristic with respect to the wavelength of the detection light receiving element 31, and the absorbance with respect to the wavelength due to water vapor. It has been.

  For example, an appropriate extinction coefficient αc1 for the detection signal can be determined by acquiring the characteristics of the optical component sensor 1 in an inspection process performed after the optical component sensor 1 is manufactured. In the inspection process, for example, the detection light LD1 is irradiated to the object 2 including a fixed amount of water in a dry atmosphere, and the reflection detection light LD2 that is the reflected light is received by the detection light receiving element 31. Let Since the amount of moisture contained in the object 2 is fixed, the correspondence relationship with the intensity of the detection signal output from the detection light receiving element 31 can be determined, and the extinction coefficient αc1 can be determined.

  Cc is absolute humidity, and is specifically calculated by the temperature / humidity detector 85. L is the distance from the housing 10 to the object 2, and is specifically calculated by the distance measuring unit 75.

  Aad is the absorptance of the detection light LD1 and the reflection detection light LD2 due to the component (moisture) contained in the object 2, and is expressed by the following (Equation 3).

(Formula 3) Aad = 10 ^{−αa × Ca × D}

  Here, αa is a predetermined extinction coefficient, and specifically, is an extinction coefficient of the detection light LD1 and the reflection detection light LD2 due to the component (water). Ca is a volume concentration of a component (moisture) contained in the object 2. D is a contribution thickness that is twice the thickness of the component that contributes to the absorption of the detection light LD1 and the reflection detection light LD2.

  More specifically, in the target object 2 in which moisture is uniformly dispersed, when light enters the target object 2 and is reflected and emitted from the target object 2, Ca is included in the components of the target object 2. This corresponds to the volume concentration. Further, D corresponds to the optical path length from the reflection inside to the emission from the object 2. For example, when the object 2 is a mesh-like solid such as a fiber or a porous solid such as a sponge, it is assumed that light is reflected on the surface of the solid. In this case, for example, Ca is the concentration of water contained in the liquid phase covering the solid. Moreover, D is the contribution thickness converted as an average thickness of the liquid phase which covers the solid substance.

  Therefore, αa × Ca × D corresponds to the amount of component (water content) contained in the object 2. From the above, it can be seen that the light energy Pd corresponding to the intensity of the detection signal changes according to the amount of water contained in the object 2 and the amount of water vapor contained in the space 3.

  Similarly, the optical energy Pr of the reflected reference light LR2 incident on the reference light receiving element 32 is expressed by the following (Equation 4).

  (Formula 4) Pr = Pr0 * Gr * Rr * Tr * Acr * Ivr

  In the present embodiment, since the reference light LR1 and the reflected reference light LR2 can be regarded as not substantially absorbed by the components included in the object 2, as can be seen by comparing with (Equation 1), A term corresponding to the moisture absorption rate Aad is not included in (Equation 4).

  In (Expression 4), Pr0 is the light energy of the reference light LR1 emitted from the reference light source 22. Gr is the coupling efficiency (condensing rate) of the reference light LR2 emitted from the reference light source 22 to the reference light receiving element 32. Specifically, Gr corresponds to the ratio of a part of the reference light LR1 that becomes part of the component diffusely reflected by the object 2 (that is, the reflected reference light LR2). Rr is the reflectance of the reference light LR1 by the object 2. Tr is the transmittance of the reflected reference light LR2 by the reference filter 62. Ivr is the light receiving sensitivity of the reference light receiving element 32 with respect to the reflected reference light LR2.

  Acr is the absorption rate of the reference light LR1 and the reflected reference light LR2 by the water vapor contained in the space 3, and is expressed by the following (formula 5).

(Formula 5) Acr = 10 ^{−αc2 × Cc × 2L}

  Here, αc2 is a predetermined second extinction coefficient, and specifically, is an equivalent extinction coefficient in the wavelength range of the reference light LR1 and the reflected reference light LR2. In the present embodiment, αc2 is determined in advance based on the emission intensity distribution with respect to the wavelength of the reference light LR1 emitted from the reference light source 22, the sensitivity characteristic with respect to the wavelength in the reference light receiving element 32, and the absorbance with respect to the wavelength due to water vapor. ing. Note that αc2 can be determined in advance in an inspection process performed after manufacturing the optical component sensor 1, in the same manner as αc1. Cc and L are the same as in the case of (Formula 2).

  In the present embodiment, since the detection light LD1 and the reference light LR1 are irradiated coaxially and with the same spot size, the coupling efficiency Gd of the detection light LD1 and the coupling efficiency Gr of the reference light LR1 are substantially equal. Further, since the detection light LD1 and the reference light LR1 have relatively close peak wavelengths, the reflectance Rd of the detection light LD1 and the reflectance Rr of the reference light LR1 are substantially equal.

  Therefore, the following (Expression 6) is derived by taking the ratio of (Expression 1) and (Expression 4).

  (Formula 6) Pd / Pr = Z × (Acd / Acr) × Aad

  Here, Z is a constant term and is represented by (Equation 7).

  (Expression 7) Z = (Pd0 / Pr0) × (Td / Tr) × (Ivd / Ivr)

  The light energies Pd0 and Pr0 are predetermined as initial outputs of the detection light source 21 and the reference light source 22, respectively. The transmittance Td of the reflected detection light LD2 and the transmittance Tr of the reflected reference light LR2 are determined in advance by the transmission characteristics of the detection filter 61 and the reference filter 62, respectively. The light receiving sensitivity Ivd of the reflected detection light LD2 and the light receiving sensitivity Ivr of the reflected reference light LR2 are determined in advance by the light receiving characteristics of the detection light receiving element 31 and the reference light receiving element 32, respectively. Therefore, Z shown in (Expression 7) can be regarded as a constant.

  The signal processing circuit 95 calculates the light energy Pd of the reflected detection light LD2 based on the detection signal, and calculates the light energy Pr of the reflected reference light LR2 based on the reference signal. Specifically, the signal level (voltage level) of the detection signal corresponds to the light energy Pd, and the signal level (voltage level) of the reference signal corresponds to the light energy Pr. Further, the correcting unit 90 calculates the absorption rates Acd and Acr due to water vapor based on (Expression 2) and (Expression 5).

  Therefore, the signal processing circuit 95 can calculate the absorption rate Aad of moisture contained in the target object 2 based on (Equation 6). Thereby, the signal processing circuit 95 can calculate the water content based on (Equation 3).

[Effects, etc.]
When the water vapor is not contained in the space 3 between the housing 10 and the object 2 or when the detection light is not absorbed by the water vapor, the signal processing circuit 95 processes the detection signal, thereby The moisture contained in 2 can be detected. However, when the detection light is absorbed by the water vapor contained in the space 3, the intensity of the detection signal is affected not only by the water contained in the object 2 but also by the water vapor contained in the space 3.

  On the other hand, the optical component sensor 1 according to the present embodiment includes a detection light source 21 that emits the detection light LD1 including the absorption wavelength due to the predetermined component, and a reference light LR1 that does not include the absorption wavelength due to the component. Reflection detection which is at least a part of the detection light LD1 reflected by the object light source 22, the casing 10 housing the detection light source 21 and the reference light source 22, and the object 2 located outside the casing 10 The detection light receiving element 31 received in the housing 10 that receives the light LD2 and the reflected reference light LR2 that is at least part of the reference light LR1 reflected by the object 2 are received in the housing 10. The received reference light receiving element 32, the distance measuring unit 75 that measures the distance from the housing 10 to the object 2, and the temperature that detects the temperature and humidity of the space 3 between the housing 10 and the object 2. Humidity detector 85 and temperature Based on the absolute humidity calculated based on the temperature and humidity detected by the degree detection unit 85, the distance measured by the distance measuring unit 75, and a predetermined extinction coefficient, output from the light receiving element 31 for detection The correction unit 90 corrects the detection signal corresponding to the reflected detection light LD2 that has been corrected, the detection signal corrected by the correction unit 90, and the reference signal corresponding to the reflected reference light LR2 output from the reference light receiving element 32. And a signal processing circuit 95 that detects components included in the object 2.

  As a result, the detection signal is corrected based on the absolute humidity of the space 3 between the housing 10 and the object 2 and the distance L from the housing 10 to the object 2, so that the absorption due to water vapor is cancelled. Can do.

  Further, in the present embodiment, absorption by moisture is rare, and a filter that requires high-accuracy transmission characteristics such as a filter that receives absorption by water vapor is not required. That is, even if there is a characteristic variation in the optical component, the influence of the characteristic variation can be suppressed by correcting the detection signal. Thereby, the optical component sensor 1 can detect moisture with high accuracy.

  Further, for example, the detection extinction coefficient includes the first emission intensity distribution with respect to the wavelength of the detection light LD1 emitted from the detection light source 21, the first sensitivity characteristic with respect to the wavelength in the detection light receiving element 31, and the absorbance with respect to the wavelength due to water vapor. Is a value determined in advance.

  Thereby, by setting the extinction coefficient for the detection signal in advance, it is possible to suppress the influence of the characteristic variation of the optical component, and to detect moisture contained in the object 2 with high accuracy.

  Further, for example, the optical component sensor 1 further includes a detection filter 61 provided on the optical path of the reflected detection light LD2, and the absorption coefficient for detection includes the first emission intensity distribution, the first sensitivity characteristic, and the like. , Based on the absorbance and the transmission characteristics of the detection filter 61 with respect to the wavelength.

  Accordingly, since the light absorption coefficient for the detection signal is determined based on the characteristics of each optical component including the transmission characteristics of the detection filter 61, the moisture contained in the object 2 can be detected with high accuracy.

  Further, for example, the correction unit 90 further includes an absolute humidity calculated based on the temperature and humidity detected by the temperature / humidity detection unit 85, a distance measured by the distance measurement unit 75, and a predetermined extinction coefficient. Based on the above, the extinction coefficient for reference is the second emission intensity distribution with respect to the wavelength of the reference light LR1 emitted from the reference light source 22, the second sensitivity characteristic with respect to the wavelength in the reference light receiving element 32, and the absorbance with respect to the wavelength due to water vapor. The signal processing circuit 95 corrects the reference signal based on the detection signal corrected by the correction unit 90 and the reference signal corrected by the correction unit 90. A component contained in the object 2 is detected.

  Thereby, even if the reference light is absorbed by water vapor, the reference signal is corrected, so that the absorption by water vapor can be canceled. In addition, by setting the extinction coefficient for the reference signal in advance, it is possible to suppress the influence of the characteristic variation of the optical component. Therefore, the optical component sensor 1 can accurately detect moisture contained in the object 2.

  Further, for example, the optical component sensor 1 further includes a reference filter 62 provided on the optical path of the reflected reference light LR2, and the reference extinction coefficient includes the second emission intensity distribution, the second sensitivity characteristic, and the like. , Based on the absorbance and the transmission characteristics with respect to the wavelength in the reference filter 62.

  Thereby, since the light absorption coefficient for the reference signal is determined based on the characteristics of each optical component including the transmission characteristics of the reference filter 62, the moisture contained in the object 2 can be detected with high accuracy.

  For example, the distance measuring unit 75 measures the distance L by a triangulation method.

  As a result, the distance L can be accurately measured by triangulation.

  Further, for example, the optical component sensor 1 further shields a part of the reflected detection light LD2 in accordance with the incident angle of the reflected detection light LD2 disposed in front of the light receiving surface of the detection light receiving element 31. A detection aperture 71 and a reference aperture 72 disposed in front of the light receiving surface of the reference light receiving element 32 for shielding a part of the reflected reference light LR2 according to the incident angle of the reflected reference light LR2 are provided. The distance measuring unit 75 measures the distance L based on the ratio of the detection signal and the reference signal.

  Thus, the distance L can be measured using the detection light source 21, the reference light source 22, the detection light receiving element 31, and the reference light receiving element 32. That is, since a new light source and light receiving element are not required, the optical component sensor 1 can be reduced in size.

(Modification 1)
Below, the modification 1 of the optical component sensor 1 which concerns on the said embodiment is demonstrated.

  In the optical component sensor 1 according to the above-described embodiment, the example in which the distance measurement unit 75 measures the distance using the detection light and the reference light has been described, but a dedicated member for distance measurement may be provided.

  FIG. 9 is a schematic diagram showing the principle of distance measurement by the triangulation method according to this modification. As shown in FIG. 9, in this modification, a position detection element 32x is used.

  Specifically, the optical component sensor according to the present modification further includes a position detection element 32x in addition to the configurations shown in FIGS. The position detection element 32x has a linear or two-dimensional light receiving surface. The position detection element 32x outputs a position signal corresponding to the light receiving position on the light receiving surface of the received light.

  The light receiving position on the light receiving surface of the position detecting element 32x changes according to the incident angle of the reflected reference light LR2. As shown in FIG. 9, the light receiving position is different between the reflected reference light LRa2 incident on the light receiving surface at a large incident angle and the reflected reference light LRb2 incident on the light receiving surface at a small incident angle. For this reason, the incident angle of the incident reflected reference light LR2 can be acquired based on the light receiving position on the light receiving surface of the position detecting element 32x.

  Specifically, the distance measuring unit 75 calculates the incident angle of the reflected light based on the position signal, and the distance L to the object 2 that is the transmission source of the reflected light by triangulation using the calculated incident angle. Is calculated. The distance measuring unit 75 stores a table in which an incident angle (or a light receiving position) is associated with a distance, and may acquire the distance L by referring to the table.

  As described above, for example, the optical component sensor according to the present modification further includes the position detection element 32x that receives the reflection detection light LD2 or the reflection reference light LR2, and the distance measurement unit 75 includes the position detection element 32x. The distance L is measured based on the light receiving position of the reflected detection light LD2 or the reflected reference light LR2.

  Thus, the distance L can be easily measured with high accuracy using the position detection element 32x.

  In the present modification, the reflected light received by the position detection element 32x may be the reflected detection light LD2 or the reflected reference light LR2. Or the optical component sensor which concerns on this modification is a light source different from the light source 21 for a detection, and the light source 22 for a reference, Comprising: You may provide the 3rd light source which emits the light for ranging. For example, the third light source emits light having a wavelength component that is not absorbed by the component (water) contained in the object 2 and the water vapor contained in the space 3. Thereby, the position detection element 32x can receive a sufficient amount of reflected light regardless of the environment of the object 2 and the space 3, so that the ranging accuracy can be improved.

  The third light source for distance measurement and the position detection element 32x are disposed in the housing 10, for example. Alternatively, it may be arranged in a case (case dedicated to distance measurement) different from the case 10. Note that the dedicated housing for distance measurement is fixed to the housing 10, for example, and the distance L to the object 2 is the same as the distance from the housing 10 to the object 2.

(Modification 2)
Subsequently, Modification 2 of the optical component sensor 1 according to the above embodiment will be described.

  In the optical component sensor 1 according to the above embodiment, the distance measuring unit 75 measures the distance L by the triangulation method, but in this modification, the distance is measured by the optical time-of-flight distance measurement (TOF: Time Of Flight) method. Measure L.

  FIG. 10 is a schematic diagram illustrating the principle of distance measurement by the TOF method according to this modification. As shown in FIG. 10, the light source 20 x irradiates the object 2 with the pulsed light LP <b> 1, and the light receiving unit 30 x receives the pulsed light LP <b> 2 reflected by the object 2. The distance measuring unit 75 measures a time Δt from when the light source 20x emits the pulsed light LP1 to when the light receiving unit 30x receives the pulsed light LP2. Δt is the time required for the pulsed light to travel back and forth the distance L to the object 2. Therefore, the distance L can be calculated based on the following (Formula 8).

  (Formula 8) L = c × Δt ÷ 2

  Note that c is the speed of light.

  In the present modification, at least one of the detection light source 21 and the reference light source 22 is used as the light source 20x. Further, at least one of the detection light receiving element 31 and the reference light receiving element 32 is used as the light receiving unit 30x. That is, the distance measuring unit 75 measures the distance L by the TOF method using the detection light or the reference light.

  Thereby, the optical component sensor according to the present modification can measure the distance L to the object 2 without adding new components for distance measurement.

  For example, the distance measuring unit 75 measures the distance L using both the detection light and the reference light. Specifically, the distance measuring unit 75 calculates an average value of the distance measured using the detection light and the distance measured using the reference light as the distance L from the housing 10 to the object 2. To do.

  More specifically, the detection light source 21 emits a pulsed detection light LD 1 based on a pulse signal from the control circuit 80. The detection light receiving element 31 receives the pulsed reflected detection light LD2 reflected by the object 2. The reference light source 22 emits the pulsed reference light LR1 based on the pulse signal from the control circuit 80. The reference light receiving element 32 receives the pulsed reflected reference light LR <b> 2 reflected by the object 2.

  The distance measuring unit 75 calculates the phase difference between the pulse signal from the control circuit 80 and the light reception signal from the detection light receiving element 31 or the reference light receiving element 32. Since the distance measuring unit 75 can calculate the time Δt from the calculated phase difference, the distance L can be calculated based on (Equation 8).

  Thereby, the measurement error of the distance L due to a difference in physical position between the detection light source 21 and the reference light source 22 and between the detection light receiving element 31 and the reference light receiving element 32 can be suppressed. In particular, when the distance L to the object 2 is small, the difference between the distance along the optical path of the detection light and the distance along the optical path of the reference light may increase, which is more useful.

  In this modification, the detection light and the reference light are used. However, light from another light source (a light source dedicated to distance measurement) may be used. Specifically, the optical component sensor according to the present modification may include a third light source dedicated to distance measurement and a third light receiving element dedicated to distance measurement. In this case, for example, the third light source emits light having a wavelength component that is not absorbed by the component (water) contained in the object 2 and the water vapor contained in the space 3. Thereby, since the 3rd light receiving element can receive reflected light of sufficient light quantity irrespective of the environment of the target object 2 and the space 3, it can improve ranging accuracy.

(Other)
As described above, the optical component sensor according to the present invention has been described based on the above-described embodiment and its modifications. However, the present invention is not limited to the above-described embodiment.

  For example, in the above embodiment, the distance L is measured using the detection light source 21, the reference light source 22, the detection light receiving element 31, and the reference light receiving element 32, but the present invention is not limited to this. The optical component sensor 1 may include a light source such as an LED element dedicated to distance measurement and a light receiving element such as a photodiode dedicated to distance measurement.

  Further, for example, in the above-described embodiment, an example in which the temperature / humidity detection unit 85 calculates the absolute humidity based on the temperature and the humidity has been described, but the correction unit 90 may calculate the absolute humidity.

  Further, for example, the optical element 40 may be a beam splitter (half mirror) or the like, and a part of the detection light LD1 and the reference light LR1 may be separated. For example, the separated part of the detection light LD1 may enter the reference light receiving element 32 as monitor light, and the separated part of the reference light LR1 may enter the detection light receiving element 31 as monitor light. . Deterioration of the detection light source 21 and the reference light source 22 can be detected using the monitor light.

  For example, in the above-described embodiment, the optical component sensor 1 detects moisture as a component included in the object 2, but is not limited thereto. For example, the optical component sensor 1 may detect alcohol or oil. For example, the optical component sensor 1 may irradiate the object 2 with detection light including an absorption wavelength due to alcohol to be detected and reference light not including an absorption wavelength due to alcohol. Moreover, the optical component sensor 1 may detect not only a liquid component but gas components, such as a carbon dioxide, for example.

  In addition, the embodiment can be realized by arbitrarily combining the components and functions in each embodiment without departing from the scope of the present invention, or a form obtained by subjecting each embodiment to various modifications conceived by those skilled in the art. Forms are also included in the present invention.

DESCRIPTION OF SYMBOLS 1 Optical component sensor 2, 2a, 2b Object 3 Space 10 Case 21 Light source for detection (1st light source)
22 Light source for reference (second light source)
31 Light-receiving element for detection (first light-receiving element)
32 Light receiving element for reference (second light receiving element)
32x position detection element 61 detection filter 62 reference filter 71 detection aperture 72 reference aperture 75 distance measurement unit 80 control circuit 85 temperature / humidity detection unit 90 correction unit 95 signal processing circuit LD1 detection light LD2 reflection detection light LR1, LRa1, LRb1 Reference light LR2, LRa2, LRb2 Reflected reference light

Claims (11)

A first light source that emits detection light including an absorption wavelength due to a predetermined component;
A second light source that emits reference light that does not include an absorption wavelength by the component;
A housing for housing the first light source and the second light source;
A first light receiving element housed in the housing for receiving reflected detection light that is at least a part of the detection light reflected by an object located outside the housing;
A second light receiving element housed in the housing for receiving reflected reference light that is at least part of the reference light reflected by the object;
A distance measuring unit for measuring a distance from the housing to the object;
A temperature and humidity detector that detects the temperature and humidity of the space between the housing and the object;
Based on the absolute humidity calculated based on the temperature and humidity detected by the temperature / humidity detector, the distance measured by the distance measuring unit, and a predetermined first extinction coefficient, A correction unit that corrects a detection signal corresponding to the reflected detection light output from the element;
A signal processing circuit for detecting the component included in the object based on the detection signal corrected by the correction unit and a reference signal corresponding to the reflected reference light output from the second light receiving element; Optical component sensor. The first extinction coefficient is preliminarily determined based on the first emission intensity distribution with respect to the wavelength of the detection light emitted from the first light source, the first sensitivity characteristic with respect to the wavelength in the first light receiving element, and the absorbance with respect to the wavelength due to water vapor. The optical component sensor according to claim 1, wherein the optical component sensor has a predetermined value. further,
A first filter provided on an optical path of the reflected detection light;
The first extinction coefficient is determined in advance based on the first emission intensity distribution, the first sensitivity characteristic, the absorbance, and a first transmission characteristic with respect to a wavelength in the first filter. The optical component sensor according to 1. The correction unit further includes an absolute humidity calculated based on the temperature and humidity detected by the temperature / humidity detection unit, a distance measured by the distance measurement unit, and a predetermined second extinction coefficient. Based on the reference signal,
The second extinction coefficient is determined in advance based on the second emission intensity distribution with respect to the wavelength of the reference light emitted from the second light source, the second sensitivity characteristic with respect to the wavelength in the second light receiving element, and the absorbance with respect to the wavelength due to water vapor. It is a fixed value,
The optical signal according to claim 2, wherein the signal processing circuit detects the component included in the object based on the detection signal corrected by the correction unit and the reference signal corrected by the correction unit. Formula component sensor. further,
A second filter provided on an optical path of the reflected reference light;
5. The second absorption coefficient is determined in advance based on the second emission intensity distribution, the second sensitivity characteristic, the absorbance, and a second transmission characteristic with respect to a wavelength in the second filter. The optical component sensor according to 1. The optical component sensor according to claim 1, wherein the distance measuring unit measures the distance by a triangulation method. further,
A position detection element that receives the reflection detection light or the reflection reference light;
The optical component sensor according to claim 6, wherein the distance measuring unit measures the distance based on a light receiving position of the reflection detection light or the reflected reference light in the position detection element. further,
A first aperture disposed in front of the light receiving surface of the first light receiving element for shielding a part of the reflected detection light according to an incident angle of the reflected detection light;
A second aperture disposed in front of the light receiving surface of the second light receiving element, for shielding a part of the reflected reference light according to an incident angle of the reflected reference light,
The optical component sensor according to claim 6, wherein the distance measuring unit measures the distance based on a ratio of the detection signal and the reference signal. The optical component sensor according to claim 1, wherein the distance measurement unit measures the distance by a time-of-flight distance measurement (TOF: Time Of Flight). The optical component sensor according to claim 9, wherein the distance measurement unit measures the distance by an optical time-of-flight distance measurement method using the detection light or the reference light. The distance measuring unit calculates an average value of a distance measured using the detection light and a distance measured using the reference light as a distance from the housing to the object. The optical component sensor according to 1.

Images