JP2019219367A - Liquid component detection system - Google Patents

Abstract

To provide a liquid component detection system capable of detecting a plurality of components of liquid while attaining downsizing.SOLUTION: A liquid component detection system 1 comprises a light guide 2, an infrared radiation source 3, and a plurality of light receiving elements 4. The light guide 2 alternately repeats total reflection at the interface between a second main surface 22 and a liquid 10 and total reflection at the interface between a first main surface 21 and a medium 9, to guide infrared light incident on an incident prism 23, and then emits the light from an emission prism 24. The infrared radiation source 3 emits infrared light toward the incident prism 23. The plurality of light receiving elements 4 receive the infrared light emitted from the emission prism 24. In the liquid component detection system 1, a plurality of infrared light paths 6 are formed. The plurality of infrared light paths 6 correspond to the plurality of light receiving elements 4 on a one-to-one basis, and each comprise the incident prism 23 and the emission prism 24. At least one of the infrared radiation source 3 and the light guide 2 is shared for forming the plurality of infrared light paths 6.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates generally to liquid component detection systems, and more particularly, to liquid component detection systems that detect components of a liquid.

  2. Description of the Related Art Conventionally, as a liquid component detection system for detecting a component of a liquid, an analyzer in which a liquid chromatograph and an infrared absorption spectrum device are combined is known (Patent Document 1).

  In the analyzer described in Patent Document 1, an infrared multiple reflection prism is attached to the outside of a liquid chromatograph infrared spectroscopic cell, or an infrared multiple reflection prism is used as a window.

JP-A-7-20046

  In the analyzer described in Patent Literature 1, in order to detect a plurality of components of a liquid, a plurality of multiple reflection prisms for infrared rays having different optical path lengths for each component is required, which increases costs.

  An object of the present disclosure is to provide a liquid component detection system capable of detecting a plurality of components of a liquid while reducing the size.

  A liquid component detection system according to an embodiment of the present disclosure detects a component of a liquid. The liquid component detection system includes a light guide, an infrared radiation source, and a plurality of light receiving elements. The light guide has a first main surface in contact with a medium and a second main surface in contact with the liquid. The light guide has an incidence prism formed on the first main surface and an emission prism formed on the first main surface. The light guide is configured to perform total reflection at an interface between the second main surface and the liquid and total reflection at an interface between the first main surface and the medium with respect to infrared light incident on the incident prism. The light is alternately and repeatedly guided to exit from the exit prism. The infrared radiation source emits infrared light toward the incident prism. The plurality of light receiving elements receive infrared light emitted from the emission prism. The liquid component detection system has a plurality of infrared light paths. The plurality of infrared light paths correspond to the plurality of light receiving elements on a one-to-one basis, and pass through the incidence prism and the emission prism, respectively. At least one of the infrared radiation source and the light guide is shared for forming the plurality of infrared light paths.

  The liquid component detection system according to an aspect of the present disclosure can detect a plurality of components of a liquid while reducing the size.

FIG. 1A is a plan view of a light guide in the liquid component detection system according to the first embodiment. FIG. 1B is a cross-sectional view of a principal part corresponding to a cross section taken along line X1-X1 of FIG. 1A, illustrating the liquid component detection system according to the first embodiment. FIG. 1C is a cross-sectional view of a principal part corresponding to a cross section taken along line X2-X2 of FIG. 1A, illustrating the liquid component detection system according to the first embodiment. It is a whole block diagram of a liquid component detection system same as the above. FIG. 3A is a plan view of a light guide in the liquid component detection system according to the second embodiment. FIG. 3B is a cross-sectional view of a principal part corresponding to a cross section taken along line X1-X1 of FIG. 3A, illustrating the liquid component detection system according to the first embodiment. FIG. 4A is a plan view of a light guide in the liquid component detection system according to the third embodiment. FIG. 4B is a cross-sectional view of a principal part corresponding to a cross section taken along line XX of FIG. 4A, illustrating the liquid component detection system according to the first embodiment. FIG. 4C is a sectional view of a principal part corresponding to a section taken along line YY of FIG. 4A, illustrating the liquid component detection system according to the first embodiment. FIG. 5A is a plan view of a light guide in the liquid component detection system according to the fourth embodiment. FIG. 5B is a cross-sectional view of a principal part corresponding to a cross section taken along line BB of FIG. 5A, illustrating the liquid component detection system according to the first embodiment. FIG. 5C is a cross-sectional view of a principal part corresponding to a cross-section taken along line CC of FIG. 5A, illustrating the liquid component detection system according to the first embodiment. FIG. 5D is a cross-sectional view of a principal part corresponding to a cross section taken along line DD of FIG. 5A, illustrating the liquid component detection system according to the first embodiment. FIG. 5E is a cross-sectional view of a principal part corresponding to a cross section taken along line EE of FIG. 5A, illustrating the liquid component detection system according to the first embodiment. FIG. 6A is a cross-sectional view of a main part of a liquid component detection system according to Embodiment 5. FIG. 6B is a cross-sectional view of a main part of the liquid component detection system according to the first embodiment. FIG. 6C is an enlarged sectional view of a main part including the incidence prism of FIGS. 6A and 6B. FIG. 6D is an enlarged sectional view of a main part including the emission prism of FIGS. 6A and 6B. FIG. 7A is a cross-sectional view of a main part of a liquid component detection system according to Embodiment 6. FIG. 7B is an enlarged sectional view of a main part including the incident prism of FIG. 7A. FIG. 7C is an enlarged view of a main part including the emission prism of FIG. 7A. FIG. 8A is a sectional view of a main part of a liquid component detection system according to a seventh embodiment. FIG. 8B is an enlarged sectional view of a main part including the incident prism of FIG. 8A. FIG. 8C is an enlarged view of a main part including the exit prism of FIG. 8A. FIG. 9A is a cross-sectional view of a main part of a liquid component detection system according to Embodiment 8. FIG. 9B is a cross-sectional view of a main part of the liquid component detection system according to the first embodiment. FIG. 9C is an enlarged sectional view of a main part including the incidence prism of FIGS. 9A and 9B. FIG. 9D is an enlarged sectional view of a main part including the emission prism of FIGS. 9A and 9B. FIG. 10A is a main-portion cross-sectional view of the liquid component detection system according to Embodiment 9. FIG. 10B is an enlarged sectional view of a main part including the incident prism of FIG. 10A. FIG. 10C is an enlarged view of a main part including the emission prism of FIG. 10A. FIG. 11A is a plan view of a light guide in the liquid component detection system according to the tenth embodiment. FIG. 11B is a cross-sectional view of a principal part corresponding to a cross section taken along line X1-X1 of FIG. 11A, illustrating the liquid component detection system according to the first embodiment. FIG. 11C is a sectional view of a principal part corresponding to the section taken along line X2-X2 of FIG. 11A, illustrating the liquid component detection system according to the first embodiment. FIG. 12A is a main-portion cross-sectional view of the liquid component detection system according to Embodiment 11. FIG. 12B is a cross-sectional view of a main part of the liquid component detection system according to the first embodiment. FIG. 13 is a circuit block diagram of a liquid component detection system according to a modification.

  1A to 12 described in the following embodiments are schematic diagrams, and the ratio of the size and thickness of each component in the drawings does not necessarily reflect the actual dimensional ratio. .

(Embodiment 1)
Hereinafter, the liquid component detection system 1 according to the first embodiment will be described with reference to FIGS. 1A to 1C and 2.

  The liquid component detection system 1 detects a component of the liquid 10. The liquid 10 is, for example, gasoline or the like. When the liquid 10 is gasoline, the components of the liquid 10 are, for example, toluene, ethanol, benzene, and the like. In the liquid 10, the specific wavelength of the infrared light differs for each component, and the absorbance of the infrared light of the specific wavelength differs.

  The liquid component detection system 1 is an ATR (Attenuated Total Reflection) type liquid component detection system that receives infrared rays totally reflected at an interface between the light guide 2 and the liquid 10.

  The liquid component detection system 1 includes a light guide 2, an infrared radiation source 3, and a plurality (for example, two) of light receiving elements 4. The broken lines with arrows in FIGS. 1B and 1C schematically show the traveling paths of infrared rays emitted from the infrared radiation source 3, guided by the light guide 2, and received by the light receiving element 4.

  The light guide 2 has a first main surface 21 in contact with the medium 9 and a second main surface 22 in contact with the liquid 10. The medium 9 is, for example, air. The light guide 2 includes an incidence prism 23 formed on the first main surface 21 and an emission prism 24 formed on the first main surface 21. The light guide 2 converts the infrared light incident on the incident prism 23 into total reflection at the interface between the second main surface 22 and the liquid 10 and total reflection at the interface between the first main surface 21 and the medium 9. The light is guided alternately and repeatedly, and is emitted from the emission prism 24.

  The infrared radiation source 3 emits infrared light toward the incident prism 23. Regarding the refractive index for infrared rays emitted from the infrared radiation source 3, the refractive index of the light guide 2 is larger than the refractive index of the liquid 10 and the refractive index of the medium 9.

  The liquid component detection system 1 includes a plurality of (for example, two) exit prisms 24. In short, the liquid component detection system 1 includes a plurality of emission prisms 24 corresponding to the plurality of light receiving elements 4 one-to-one. The plurality of light receiving elements 4 receive the infrared light emitted from the corresponding emission prism 24.

  The liquid component detection system 1 detects, for example, a plurality of different components of the liquid 10 from output signals of the plurality of light receiving elements 4. Here, the liquid component detection system 1 further includes a plurality (two) of optical filters 5 corresponding to the plurality (two) of the light receiving elements 4 on a one-to-one basis. The plurality of optical filters 5 have transmission characteristics different from each other.

  The liquid component detection system 1 detects different components of the liquid 10 from output signals of each of the plurality of light receiving elements 4. Here, the liquid component detection system 1 further includes a processing circuit 8 that performs signal processing on output signals of the plurality of light receiving elements 4.

  The liquid component detection system 1 may further include a pipe 7 through which the liquid 10 passes. The pipe 7 has an opening 73 between the inlet 71 and the outlet 72 of the liquid 10. The light guide 2 is arranged so as to cover the opening 73 of the pipe 7. Thereby, in the light guide 2, the second main surface 22 can be in contact with the liquid 10 inside the pipe 7, and the first main surface 21 can be in contact with the medium (for example, air) outside the pipe 7. it can.

  Each component of the liquid component detection system 1 will be described in more detail below.

  As described above, the liquid component detection system 1 includes the infrared radiation source 3, the light guide 2, and the two light receiving elements 4.

  The infrared radiation source 3 is configured to emit infrared light by thermal radiation. Here, the infrared radiation source 3 radiates infrared rays by thermal radiation when energized by a drive circuit. The infrared radiation source 3 includes, for example, an infrared radiation element. The infrared radiating element includes a semiconductor substrate, an insulating layer, and an infrared radiating layer. The semiconductor substrate has a first main surface and a second main surface, and has a hole penetrating in the thickness direction. The insulating layer is formed on the first main surface of the semiconductor substrate so as to close the hole on the first main surface side of the semiconductor substrate. The infrared emitting layer is formed on the insulating layer. The infrared radiation layer generates heat when energized, and emits infrared radiation by heat radiation. The material of the infrared radiation layer is, for example, platinum, tantalum nitride, or the like. The infrared radiation element can be manufactured using, for example, MEMS (micro electro mechanical systems) manufacturing technology or the like.

  Since the infrared radiation source 3 is configured to emit infrared light by heat radiation, it can emit infrared light in a wider wavelength range than an infrared light emitting diode. The infrared radiation source 3 can emit broadband infrared light including the absorption wavelength of each of a plurality of components of the liquid 10. The wavelength range of the infrared radiation emitted from the infrared radiation source 3 includes an absorption wavelength specific to each of the plurality of components of the liquid 10, and is, for example, 2 μm to 15 μm. Thereby, the liquid component detection system 1 can detect a plurality of components of the liquid 10 separately.

  The infrared radiation source 3 is arranged to emit infrared light toward the incident prism 23 of the light guide 2. Here, the infrared radiation source 3 is separated from the incidence prism 23 in the first direction D1. Thereby, the infrared radiation emitted from the infrared radiation source 3 is incident on the incidence prism 23. The incidence prism 23 refracts infrared light from the infrared radiation source 3 and directs the infrared light toward the second main surface 22. Note that the infrared radiation source 3 may be disposed in a direction inclined with respect to the first direction D1.

  The light guide 2 has a plate shape. The outer peripheral shape of the light guide 2 viewed from the thickness direction of the light guide 2 is, for example, a rectangular shape. Here, the light guide 2 has a rectangular plate shape. The first main surface 21 and the second main surface 22 of the light guide 2 are orthogonal to the first direction D1 parallel to the thickness direction of the light guide 2. In the light guide 2, the second main surface 22 is located on the opposite side of the first main surface 21 in the first direction D1. Hereinafter, a direction parallel to the longitudinal direction of the light guide 2 will be described as a second direction D2.

  The incidence prism 23 protrudes from the first main surface 21. The incident prism 23 has an incident surface 230 that refracts the incident infrared light in a first predetermined direction (one direction toward a region between the incident prism 23 and the output prism 24 of the second main surface 22). are doing. The entrance surface 230 is inclined with respect to the first main surface 21.

  The material of the light guide 2 is silicon. The light guide 2 is formed by processing a silicon substrate. The first main surface 21 of the light guide 2 is, for example, a (100) plane. The incidence prism 23 of the light guide 2 is formed by anisotropic etching utilizing the crystal plane orientation dependence of the etching rate of the silicon substrate. Therefore, the incidence surface 230 of the incidence prism 23 is a {111} surface. The angle (inner angle) between the incident surface 230 and the first main surface 21 is 54.7 °. Therefore, in the light guide 2, the infrared light incident from the incident surface 230 is totally reflected at the interface between the second main surface 22 of the light guide 2 and the liquid 10. The etchant used for performing the anisotropic etching is, for example, a TMAH solution heated to a predetermined temperature (for example, 85 ° C.). The etching solution is not limited to the TMAH solution, and another alkaline solution (for example, a KOH solution) may be used.

  In the third direction D3 orthogonal to the first direction D1 and the second direction D2, the length of the incidence prism 23 is longer than the length of each of the plurality of emission prisms 24.

  Each of the two exit prisms 24 protrudes from the first main surface 21. Each of the two exit prisms 24 is separated from the entrance prism 23 in a second direction D2 parallel to the longitudinal direction of the light guide 2. The plurality of exit prisms 24 overlap the entrance prism 23 in the second direction D2.

  Each of the two exit prisms 24 transmits the infrared light that has been repeatedly reflected in the light guide 2 and is incident on the second main surface 21 in a second predetermined direction (a direction parallel to the first direction D <b> 1). (In a direction parallel to the line). The emission surface 240 is inclined with respect to the first main surface 21. Here, the exit prism 24 of the light guide 2 is formed by anisotropic etching utilizing the crystal plane orientation dependence of the etching rate of the silicon substrate. Therefore, the exit surface 240 of the exit prism 24 is a {111} plane. The angle (inner angle) between the light exit surface 240 and the first main surface 21 is 54.7 °. Infrared light that has entered the emission surface 240 from inside the light guide 2 is refracted at the interface between the emission prism 24 and the medium 9. The angle (inner angle) between the exit surface 240 and the first main surface 21 is the same as the angle (inner angle) between the incident surface 230 and the first main surface 21.

  In the liquid component detection system 1, when infrared rays are totally reflected at the interface between the light guide 2 and the liquid 10 (the second main surface 22 of the light guide 2), the evanescent wave enters the liquid 10 and Absorbed and attenuated. Therefore, the liquid component detection system 1 can detect the component of the liquid 10 by detecting the amount of attenuation of infrared rays. The attenuation of infrared rays increases as the number of times of total reflection at the interface between the light guide 2 and the liquid 10 increases.

  The two exit prisms 24 include a first exit prism 241 and a second exit prism 242. In the liquid component detection system 1, the distance between the incident prism 23 and the first output prism 241 is longer than the distance between the incident prism 23 and the second output prism 242. Thus, the number of times that the infrared light that enters the incident prism 23 and exits from the first exit prism 241 is totally reflected is the number of times that the infrared light that enters the incident prism 23 and exits from the first exit prism 241 is totally reflected. More times than is done. The liquid component detection system 1 detects a component having a relatively small absorbance among a plurality of components of the liquid 10 based on the attenuation of the infrared light emitted from the first emission prism 241. Further, the liquid component detection system 1 detects a component having a relatively large absorbance among a plurality of components of the liquid 10 based on the attenuation amount of the infrared light emitted from the second emission prism 242. Therefore, in the liquid component detection system 1, it is possible to improve the detection accuracy of each component.

  In the light guide 2, the first exit prism 241 and the second exit prism 242 are located on the same side as viewed from the entrance prism 23. More specifically, the first exit prism 241 and the second exit prism 242 are located on the same side as viewed from the entrance prism 23 in the second direction D2.

  In the liquid component detection system 1, since the light guide 2 includes the incidence prism 23 and the emission prism 24 protruding from the first main surface 21, the first main surface 21 and the second main surface of the light guide 2 are provided. 22 can be reduced, and the number of times that infrared rays are totally reflected can be increased. Thereby, in the liquid component detection system 1, the detection accuracy of the components of the liquid 10 is improved. In addition, in the liquid component detection system 1, since the number of times of total reflection of infrared rays can be increased, the linear distance between the incident prism 23 and the output prism 24 can be shortened. Can be achieved.

  The two light receiving elements 4 are separated from the two emission prisms 24 corresponding to each other in the thickness direction of the light guide 2. Each of the two light receiving elements 4 is arranged at a position where infrared light emitted from the corresponding emission prism 24 can be received. Thereby, each of the two light receiving elements 4 receives the infrared light emitted from the corresponding emission prism 24. Each of the two light receiving elements 4 can receive an infrared ray and generate an output signal obtained by photoelectric conversion. Each of the two light receiving elements 4 is, for example, a pyroelectric element, and outputs a current signal as an output signal.

  The liquid component detection system 1 can change, for example, the number of components to be detected in the liquid 10 according to the number of the light receiving elements 4. The liquid component detection system 1 includes two optical filters 5 corresponding to the two light receiving elements 4 on a one-to-one basis. The two optical filters 5 are arranged in front of (the light receiving surface of) the corresponding light receiving element 4. The two optical filters 5 transmit infrared rays having different wavelengths from each other. Each of the two optical filters 5 is an optical bandpass filter having a pass band including a specific absorption wavelength that is absorbed by any one of components of the liquid 10 to be measured (detected).

  The liquid component detection system 1 includes a circuit board 11 on which an infrared radiation source 3 and a plurality of (two) light receiving units 45 each including a corresponding light receiving element 4 and an optical filter 5 are mounted (see FIG. 2). Each of the plurality of light receiving units 45 has a package holding the light receiving element 4 and the optical filter 5.

  Hereinafter, for convenience of explanation, of the two light receiving elements 4, the light receiving element 4 corresponding to the first emission prism 241 is referred to as a first light receiving element 41, and the light receiving element 4 corresponding to the second emission prism 242 is referred to as a second light receiving element. It may be referred to as a light receiving element 42. The optical filter 5 corresponding to the first light receiving element 41 among the two optical filters 5 is referred to as a first optical filter 51, and the optical filter 5 corresponding to the second light receiving element 42 is referred to as a second optical filter 52. is there.

  The transmission wavelength range of the first optical filter 51 is determined so as to transmit infrared light having an absorption wavelength of a first component of the liquid 10 to be detected (hereinafter, also referred to as a first specific wavelength). The transmission wavelength range of the second optical filter 52 is determined so as to transmit infrared light having an absorption wavelength of a second component of the liquid 10 to be detected (hereinafter, also referred to as a second specific wavelength). When the liquid 10 is gasoline, the first component is, for example, toluene, and the second component is, for example, ethanol. The first specific wavelength and the second specific wavelength are different from each other. The transmission wavelength range of the first optical filter 51 and the transmission wavelength range of the second optical filter 52 are determined so as not to overlap with each other.

  In the liquid component detection system 1, a plurality (two) of infrared light paths 6 are formed. The two infrared light paths 6 correspond to the two light receiving elements 4 on a one-to-one basis, and pass through the incidence prism 23 and the emission prism 24, respectively. The infrared light path 6 is an infrared light path formed between the infrared radiation source 3 and the light receiving element 4. 1B and 1C, the infrared light path 6 is indicated by a broken line with an arrow. The two infrared light paths 6 are formed between a first infrared light path 61 formed between the infrared radiation source 3 and the first light receiving element 41 and between the infrared radiation source 3 and the second light receiving element 42. A second infrared light path 62. In the liquid component detection system 1, both the infrared radiation source 3 and the light guide 2 are shared for forming two infrared light paths 6. The two infrared light paths 6 have different infrared light path lengths.

  The processing circuit 8 detects different components of the liquid 10 by performing signal processing on output signals of the two light receiving elements 4. The processing circuit 8 determines the concentrations of the two components of the liquid 10 based on the output signals of the two light receiving elements 4. The processing circuit 8 includes, for example, a first current-to-voltage conversion circuit, a first amplification circuit, a second current-to-voltage conversion circuit, a second amplification circuit, and an internal processing circuit. The first current-voltage conversion circuit performs current-voltage conversion on the output signal of the first light receiving element 41 and outputs the converted signal. The first amplification circuit amplifies an output signal of the first current-voltage conversion circuit. The second current-voltage conversion circuit performs current-voltage conversion on the output signal of the second light receiving element 42 and outputs the converted signal. The second amplifier circuit amplifies and outputs an output signal of the second current-voltage conversion circuit. The internal processing circuit obtains the concentration of the first component of the liquid 10 based on the output signal of the first amplifier circuit, and obtains the concentration of the second component of the liquid 10 based on the output signal of the second amplifier circuit. The execution subject of the internal processing circuit includes a computer system. The computer system has one or more computers. The computer system mainly has a processor and a memory as hardware. When the processor executes a program recorded in the memory of the computer system, a function as an execution subject of the internal processing circuit in the present disclosure is realized. The program may be recorded in the memory of the computer system in advance, or may be provided through an electric communication line, or may be provided in a non-temporary storage medium such as a memory card, an optical disk, or a hard disk drive (magnetic disk) readable by the computer system. May be provided by being recorded on a dynamic recording medium. A processor of a computer system includes one or more electronic circuits including a semiconductor integrated circuit (IC) or a large-scale integrated circuit (LSI). A plurality of electronic circuits may be integrated on one chip, or may be provided separately on a plurality of chips. A plurality of chips may be integrated in one device, or may be provided separately in a plurality of devices.

(effect)
The liquid component detection system 1 according to the first embodiment detects a component of the liquid 10. The liquid component detection system 1 includes a light guide 2, an infrared radiation source 3, and a plurality of light receiving elements 4. The light guide 2 has a first main surface 21 in contact with the medium 9 and a second main surface 22 in contact with the liquid 10. The light guide 2 includes an incidence prism 23 formed on the first main surface 21 and an emission prism 24 formed on the first main surface 21. The light guide 2 converts the infrared light incident on the incident prism 23 into total reflection at the interface between the second main surface 22 and the liquid 10 and total reflection at the interface between the first main surface 21 and the medium 9. The light is guided alternately and repeatedly, and is emitted from the emission prism 24. The infrared radiation source 3 emits infrared light toward the incident prism 23. The plurality of light receiving elements 4 receive the infrared light emitted from the emission prism 24. In the liquid component detection system 1, a plurality of infrared light paths 6 are formed. The plurality of infrared light paths 6 correspond to the plurality of light receiving elements 4 on a one-to-one basis, and pass through the incidence prism 23 and the emission prism 24, respectively. At least one of the infrared radiation source 3 and the light guide 2 is shared for forming a plurality of infrared light paths 6. Thus, the liquid component detection system 1 according to the first embodiment can detect a plurality of components of the liquid 10 while reducing the size.

  The liquid component detection system 1 according to the first embodiment includes a plurality of exit prisms 24. Both the infrared radiation source 3 and the light guide 2 are shared for forming a plurality of infrared light paths 6. The plurality of exit prisms 24 include a first exit prism 241 and a second exit prism 242. The distance between the incidence prism 23 and the first emission prism 241 is longer than the distance between the incidence prism 23 and the second emission prism 242. Accordingly, in the liquid component detection system 1 according to the first embodiment, the light receiving element 4 (first light receiving element 41) that detects infrared light emitted from the first emission prism 241 for detecting a component having relatively low absorbance is used. By using the output signal and using the output signal of the light receiving element 4 (second light receiving element 42) for detecting the infrared ray emitted from the second emission prism 242 for detecting a component having a relatively high absorbance, the absorbance is reduced. It is possible to improve the detection accuracy of a plurality of components different from each other.

  In the liquid component detection system 1 according to the first embodiment, the first exit prism 241 and the second exit prism 242 are located on the same side as viewed from the entrance prism 23. Thereby, in the liquid component detection system 1 according to the first embodiment, the size of the light guide 2 can be reduced.

(Embodiment 2)
Hereinafter, the liquid component detection system 1a according to the second embodiment will be described with reference to FIGS. 3A and 3B. Regarding the liquid component detection system 1a according to the second embodiment, the same components as those of the liquid component detection system 1 according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The liquid component detection system 1a according to the second embodiment includes a light guide 2a instead of the light guide 2 of the liquid component detection system 1 according to the first embodiment. In the liquid component detection system 1a according to the second embodiment, both the infrared radiation source 3 and the light guide 2a are shared for forming a plurality (two) of infrared light paths 6. In the liquid component detection system 1a according to the second embodiment, the first exit prism 241 and the second exit prism 242 are located on opposite sides of the entrance prism 23. More specifically, the first exit prism 241 and the second exit prism 242 are located on opposite sides of the entrance prism 23 in the second direction D2. Thus, in the liquid component detection system 1a according to the second embodiment, the plurality of exit prisms 24 (the first exit prism 241 and the second exit prism 242) are different from the liquid component detection system 1 according to the first embodiment. It is possible to increase the area of each emission surface 240. Therefore, the detection accuracy can be improved as compared with the liquid component detection system 1 according to the first embodiment.

(Embodiment 3)
Hereinafter, the liquid component detection system 1b according to the third embodiment will be described with reference to FIGS. Regarding the liquid component detection system 1b according to the third embodiment, the same components as those of the liquid component detection system 1a according to the second embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The liquid component detection system 1b according to the third embodiment includes a light guide 2b instead of the light guide 2a of the liquid component detection system 1a according to the second embodiment (see FIGS. 3A and 3B). In the liquid component detection system 1b according to the third embodiment, both the infrared radiation source 3 and the light guide 2b are shared for forming a plurality (four) of infrared light paths 6.

  In the liquid component detection system 1b according to the third embodiment, the light guide 2b has one incident prism 23b and a plurality (four) of exit prisms 24. The plurality (four) of exit prisms 24 further include a third exit prism 243 and a fourth exit prism 244. The incidence prism 23b has a quadrangular pyramid shape. The third exit prism 243 and the fourth exit prism 244 are located on opposite sides of the entrance prism 23b. More specifically, the third exit prism 243 and the fourth exit prism 244 are located on opposite sides of the entrance prism 23b in the third direction D3. The direction in which the first emission prism 241 and the second emission prism 242 are arranged crosses the direction in which the third emission prism 243 and the fourth emission prism 244 are arranged. More specifically, the direction in which the first emission prism 241 and the second emission prism 242 are arranged is a direction parallel to the second direction D2, and the third emission prism 243, the fourth emission prism 244, Are parallel to the third direction D3, the direction in which the first emission prism 241 and the second emission prism 242 are aligned is the third emission prism 243 and the fourth emission prism 244. Are orthogonal to the direction in which are arranged, but need not necessarily be orthogonal.

  In the liquid component detection system 1b according to the third embodiment, it is possible to improve the detection accuracy of each of the four components of the liquid 10.

  In the following, for convenience of description, of the four light receiving elements 4, the light receiving element 4 corresponding to the third emission prism 243 is referred to as a third light receiving element 43, and the light receiving element 4 corresponding to the fourth emission prism 244 is referred to as a fourth light receiving element. It may be referred to as a light receiving element 44. Further, among the four optical filters 5, the optical filter 5 corresponding to the third light receiving element 43 is referred to as a third optical filter 53, and the optical filter 5 corresponding to the fourth light receiving element 44 is referred to as a fourth optical filter 54. is there.

  In the liquid component detection system 1b according to the third embodiment, since four infrared light paths 6 are formed, one of the four infrared light paths 6 is used as the light path of the infrared light of the reference wavelength, and the liquid 10 is used. The concentrations of the three components may be detected. In this case, in the processing circuit provided in place of the processing circuit 8 of the liquid component detection system 1 according to the first embodiment, for example, the light reception corresponding to the optical filter 5 (for example, the fourth optical filter 54) that transmits the infrared light of the reference wavelength. The output signal of the element 4 (the fourth light receiving element 44) corresponds to the optical filter 5 (for example, any of the first to third optical filters 51 to 53) that transmits infrared light having an absorption wavelength corresponding to the component to be detected. The concentration of each component can be detected based on the difference or ratio with the output signal of the light receiving element 4 (for example, any of the first to third light receiving elements 41 to 43). Here, the infrared light of the reference wavelength is an infrared light of a wavelength that is hardly absorbed by the liquid 10 among the infrared light emitted from the infrared radiation source 3. More specifically, the infrared light having the reference wavelength is an infrared light having a wavelength that is not absorbed by the component to be detected in the liquid 10 or is hardly absorbed as compared with the infrared light having the specific wavelength. Thus, the liquid component detection system 1b according to the third embodiment can detect the concentration of each component with higher accuracy.

(Embodiment 4)
Hereinafter, the liquid component detection system 1c according to the fourth embodiment will be described with reference to FIGS. Regarding the liquid component detection system 1c according to the fourth embodiment, the same components as those of the liquid component detection system 1 according to the first embodiment (see FIGS. 1A and 2) are denoted by the same reference numerals and description thereof is omitted.

  The liquid component detection system 1c according to the fourth embodiment includes a light guide 2c instead of the light guide 2 of the liquid component detection system 1 according to the first embodiment. In the liquid component detection system 1c according to the fourth embodiment, both the infrared radiation source 3 and the light guide 2c are shared for forming a plurality (eight) of infrared light paths 6.

  In the liquid component detection system 1c, the light guide 2c includes one incident prism 23c and a plurality of (eight) exit prisms 24c. The incidence prism 23c has a conical shape. In the liquid component detection system 1c, the center of the infrared radiation source 3 and the center of the incident prism 23c are aligned in the first direction D1.

  The eight exit prisms 24c are arranged so as to surround the entrance prism 23c. The eight exit prisms 24c are arranged so as not to overlap each other in the radial direction of the bottom surface of the conical entrance prism 23c. The eight exit prisms 24c are formed in a fan-shaped arc shape in which the center angles are substantially the same in a concentric circle with the entrance prism 23c as viewed from the thickness direction of the light guide 2c. . The light guide 2c may be formed using, for example, a mold or may be formed by cutting.

  The incidence prism 23c is not limited to a conical shape, and may be a truncated conical shape. The number of the exit prisms 24c is not limited to eight, but may be 5 to 7, 9 or more. In short, the number of exit prisms 24 may be five or more.

  The liquid component detection system 1c according to the fourth embodiment can detect more components of the liquid 10 than the liquid component detection system 1 according to the first embodiment.

(Embodiment 5)
Hereinafter, a liquid component detection system 1d according to the fifth embodiment will be described with reference to FIGS. Regarding the liquid component detection system 1d according to the fifth embodiment, the same components as those of the liquid component detection system 1 according to the first embodiment (see FIGS. 1A to 2) are denoted by the same reference numerals, and description thereof will be appropriately omitted.

  The liquid component detection system 1d according to the fifth embodiment includes a light guide 2d instead of the light guide 2 of the liquid component detection system 1 according to the first embodiment. In the liquid component detection system 1d according to the fifth embodiment, both the infrared radiation source 3 and the light guide 2d are shared for forming a plurality (two) of infrared light paths 6.

  The light guide 2d has an input prism 23d and an output prism 24d instead of the input prism 23 and the output prism 24 of the light guide 2.

  The incident prism 23d has a plurality of (two) incident surfaces 230d on which infrared rays from the infrared radiation source 3 are incident. The two incident surfaces 230d have different angles with respect to the first main surface 21 (angles with respect to a plane parallel to the first main surface 21). The two incident surfaces 230d are adjacent to each other. The two incident surfaces 230d are arranged without a gap in the second direction D2 when viewed from the first direction D1 (when viewed from the infrared radiation source 3). 6A and 6C, the angle of one incident surface 230d (231d) of the two incident surfaces 230d with respect to the first principal surface 21 is θ1, and the angle of the other incident surface 230d (232d) with respect to the first principal surface 21 is θ1. θ2. Here, the incident prism 23d satisfies the relationship of θ1> θ2.

  The exit prism 24d has a plurality (two) of exit surfaces 240d for emitting infrared rays from the infrared radiation source 3. The two exit surfaces 240d have different angles with respect to the first main surface 21 (angles with respect to a plane parallel to the first main surface 21). The two emission surfaces 240d are adjacent to each other. The two emission surfaces 240d are arranged without a gap in the second direction D2 when viewed from the first direction D1. On the other hand, the two light receiving elements 4 are arranged in the second direction D2. The plurality of entrance surfaces 230d and the plurality of exit surfaces 240d correspond one-to-one, and the angles of the corresponding entrance surfaces 230d and exit surfaces 240d with respect to the first main surface 21 are the same. For this reason, in FIGS. 6A and 6D, the angle of one of the two emission surfaces 240 d (241 d) with respect to the first main surface 21 is θ1, and the other of the two emission surfaces 240 d (242 d) is the first main surface 21. Is set to θ2. Here, the exit prism 24d satisfies the relationship of θ1> θ2.

  In the liquid component detection system 1d according to the fifth embodiment, the two light receiving elements 4 are adjacent to each other in the second direction D2.

  In the liquid component detection system 1d according to the fifth embodiment, the two infrared light paths 6 include a first infrared light path 61 formed between the infrared radiation source 3 and the first light receiving element 41, A second infrared light path 62 formed between the first light receiving element 42 and the second light receiving element 42. In the liquid component detection system 1d according to the fifth embodiment, the infrared light incident on the incident surface 231d of the incident prism 23d and the infrared light incident on the incident surface 232d of the incident prism 23d cause the light guide 2d and the liquid 10 to intersect each other. The period at which total reflection occurs at the interface is different. Thereby, in the liquid component detection system 1d according to the fifth embodiment, the optical path length of the first infrared optical path 61 and the optical path length of the second infrared optical path 62 can be made different.

  The liquid component detection system 1d according to the fifth embodiment detects a component of the liquid 10. The liquid component detection system 1d includes a light guide 2d, an infrared radiation source 3, and a plurality of light receiving elements 4. The light guide 2 d has a first main surface 21 in contact with the medium 9 and a second main surface 22 in contact with the liquid 10. The light guide 2 d has an incident prism 23 d formed on the first main surface 21 and an emission prism 24 d formed on the first main surface 21. The light guide 2d converts the infrared light incident on the incident prism 23d into total reflection at the interface between the second main surface 22 and the liquid 10 and total reflection at the interface between the first main surface 21 and the medium 9. The light is alternately and repeatedly guided to be emitted from the emission prism 24d. The infrared radiation source 3 radiates infrared rays toward the incident prism 23d. The plurality of light receiving elements 4 receive the infrared light emitted from the emission prism 24d. In the liquid component detection system 1d, a plurality of infrared light paths 6 are formed. The plurality of infrared light paths 6 correspond to the plurality of light receiving elements 4 on a one-to-one basis, and pass through the entrance prism 23d and the exit prism 24d, respectively. Both the infrared radiation source 3 and the light guide 2d are shared for forming a plurality of infrared light paths 6. Accordingly, the liquid component detection system 1d according to the fifth embodiment can detect a plurality of components of the liquid 10 while reducing the size.

  Further, in the liquid component detection system 1d according to the fifth embodiment, it is possible to detect a plurality of components of the liquid 10 using one incident prism 23d and one exit prism 24d.

(Embodiment 6)
Hereinafter, a liquid component detection system 1e according to the sixth embodiment will be described with reference to FIGS. Regarding the liquid component detection system 1e according to the sixth embodiment, the same components as those of the liquid component detection system 1d according to the fifth embodiment (see FIGS. 6A to 6D) are denoted by the same reference numerals and description thereof is omitted.

  The liquid component detection system 1e according to the sixth embodiment includes a light guide 2e instead of the light guide 2d of the liquid component detection system 1d according to the fifth embodiment. In the liquid component detection system 1e according to the sixth embodiment, both the infrared radiation source 3 and the light guide 2e are shared for forming a plurality (two) of infrared light paths 6.

  The light guide 2e has an entrance prism 23e and an exit prism 24e instead of the entrance prism 23 and the exit prism 24 of the light guide 2d. The input prism 23 and the output prism 24 of the light guide 2d are convex portions protruding from the first main surface 21, whereas the input prism 23e and the output prism 24e of the light guide 2e are the first prism. The recess (groove) is recessed from the main surface 21.

  The incident prism 23e has a plurality of (two) incident surfaces 230e at which angles with respect to the first main surface 21 (angles with respect to a plane parallel to the first main surface 21) are different from each other and on which infrared rays from the infrared radiation source 3 are incident. . 7A and 7B, the angle of one of the two incident surfaces 230e (231e) with respect to the first principal surface 21 is θ1e, and the angle of the other incident surface 230e (232e) with respect to the first principal surface 21 is two. θ2e. Here, the incident prism 23e satisfies the relationship of θ1e ≠ θ2e. In the incident prism 23e, θ1e <θ2e.

  The emission prism 24e has a plurality of (two) emission surfaces 240e that differ in angle with respect to the first main surface 21 (angle with respect to a plane parallel to the first main surface 21) and emit infrared light from the infrared radiation source 3. . The plurality of entrance surfaces 230e and the plurality of exit surfaces 240e correspond one-to-one, and the angles of the corresponding entrance surfaces 230e and exit surfaces 240e with respect to the first main surface 21 are the same. For this reason, in FIGS. 7A and 7C, the angle of one of the emission surfaces 240e (241e) of the two emission surfaces 240e with respect to the first main surface 21 is θ1e, and the other of the other emission surfaces 240e (242e) is the first main surface 21. Θ2e. Here, the exit prism 24e satisfies the relationship of θ1e ≠ θ2e. In the emission prism 24e, θ1e <θ2e.

  In the liquid component detection system 1e according to the sixth embodiment, the two light receiving elements 4 are adjacent to each other in the second direction D2.

  In the liquid component detection system 1e according to the sixth embodiment, the two infrared light paths 6 include a first infrared light path 61 formed between the infrared radiation source 3 and the first light receiving element 41, a first infrared light path 3 A second infrared light path 62 formed between the first light receiving element 42 and the second light receiving element 42. In the liquid component detection system 1e according to the sixth embodiment, the infrared light incident on the incident surface 231e of the incident prism 23e and the infrared light incident on the incident surface 232e of the incident prism 23e cause the light guide 2e and the liquid 10 to communicate with each other. The period at which total reflection occurs at the interface is different. Accordingly, in the liquid component detection system 1e according to the sixth embodiment, the optical path length of the first infrared optical path 61 and the optical path length of the second infrared optical path 62 can be made different.

  The liquid component detection system 1e according to the sixth embodiment detects a component of the liquid 10. The liquid component detection system 1e includes a light guide 2e, an infrared radiation source 3, and a plurality of light receiving elements 4. The light guide 2 e has a first main surface 21 in contact with the medium 9 and a second main surface 22 in contact with the liquid 10. The light guide 2 e has an incidence prism 23 e formed on the first main surface 21 and an emission prism 24 e formed on the first main surface 21. The light guide 2e converts the infrared light incident on the incident prism 23e into total reflection at the interface between the second main surface 22 and the liquid 10 and total reflection at the interface between the first main surface 21 and the medium 9. The light is alternately and repeatedly guided to be emitted from the emission prism 24e. The infrared radiation source 3 radiates infrared rays toward the incident prism 23e. The plurality of light receiving elements 4 receive the infrared light emitted from the emission prism 24e. In the liquid component detection system 1e, a plurality of infrared light paths 6 are formed. The plurality of infrared light paths 6 correspond to the plurality of light receiving elements 4 on a one-to-one basis, and pass through the incidence prism 23e and the emission prism 24e, respectively. Both the infrared radiation source 3 and the light guide 2 e are shared for forming a plurality of infrared light paths 6. Thus, the liquid component detection system 1e according to the sixth embodiment can detect a plurality of components of the liquid 10 while reducing the size.

  In the liquid component detection system 1e according to the sixth embodiment, it is possible to detect a plurality of components of the liquid 10 using one incident prism 23e and one exit prism 24e.

(Embodiment 7)
Hereinafter, a liquid component detection system 1f according to the seventh embodiment will be described with reference to FIGS. 8A and 8B. Regarding the liquid component detection system 1f according to the seventh embodiment, the same components as those of the liquid component detection system 1e according to the sixth embodiment (see FIGS. 7A to 7C) are denoted by the same reference numerals and description thereof is omitted.

  The liquid component detection system 1f according to the seventh embodiment includes a light guide 2f instead of the light guide 2e of the liquid component detection system 1e according to the sixth embodiment. In the liquid component detection system 1f according to the seventh embodiment, both the infrared radiation source 3 and the light guide 2f are shared for forming a plurality (two) of infrared light paths 6.

  The light guide 2f has an incident prism 23f and an output prism 24f instead of the incident prism 23e and the output prism 24e of the light guide 2e.

  The incident prism 23f has a plurality of (two) incident surfaces 230f at which angles with respect to the first main surface 21 (angles with respect to a plane parallel to the first main surface 21) are different from each other, and into which infrared rays from the infrared radiation source 3 are incident. . 8A and 8B, the angle of one of the two incident surfaces 230f (231f) with respect to the first principal surface 21 is θ1f, and the angle of the other incident surface 230f (232f) with respect to the first principal surface 21 is two. θ2f. Here, the incident prism 23f satisfies the relationship of θ1f ≠ θ2f. In the incident prism 23f, θ1f> θ2f.

  The exit prism 24f has a plurality of (two) exit surfaces 240f that differ from each other in angle with respect to the first main surface 21 (angle with respect to a plane parallel to the first main surface 21) and emit infrared rays from the infrared radiation source 3. . The plurality of entrance surfaces 230f and the plurality of exit surfaces 240f correspond one-to-one, and the angles of the corresponding entrance surfaces 230f and exit surfaces 240f with respect to the first main surface 21 are the same. For this reason, in FIGS. 8A and 8C, the angle of one of the outgoing surfaces 240f (241f) with respect to the first main surface 21 of the two outgoing surfaces 240f is θ1f, and the first main surface 21 of the other outgoing surface 240f (242f) is set. Is set to θ2f. Here, the exit prism 24f satisfies the relationship of θ1f ≠ θ2f. In the emission prism 24f, θ1f> θ2f.

  In the liquid component detection system 1f according to the seventh embodiment, the two infrared light paths 6 include a first infrared light path 61 formed between the infrared radiation source 3 and the first light receiving element 41; A second infrared light path 62 formed between the first light receiving element 42 and the second light receiving element 42. In the liquid component detection system 1f according to the seventh embodiment, the infrared light incident on the incident surface 231f of the incident prism 23f and the infrared light incident on the incident surface 232f of the incident prism 23f cause the light guide 2f and the liquid 10 to communicate with each other. The period at which total reflection occurs at the interface is different. Thereby, in the liquid component detection system 1f according to the seventh embodiment, the optical path length of the first infrared optical path 61 and the optical path length of the second infrared optical path 62 can be made different.

  In the liquid component detection system 1f according to the seventh embodiment, a plurality of infrared light paths 6 are formed as in the liquid component detection system 1e according to the sixth embodiment. The plurality of infrared light paths 6 correspond to the plurality of light receiving elements 4 on a one-to-one basis, and pass through the entrance prism 23f and the exit prism 24f, respectively. Both the infrared radiation source 3 and the light guide 2 f are shared for forming a plurality of infrared light paths 6. Thus, the liquid component detection system 1f according to the seventh embodiment can detect a plurality of components of the liquid 10 while reducing the size.

(Embodiment 8)
Hereinafter, a liquid component detection system 1g according to the eighth embodiment will be described with reference to FIGS. 9A to 9D. Regarding the liquid component detection system 1g according to the eighth embodiment, the same components as those of the liquid component detection system 1d according to the fifth embodiment (see FIGS. 6A to 6D) are denoted by the same reference numerals and description thereof is omitted.

  The liquid component detection system 1g according to the eighth embodiment includes a light guide 2g instead of the light guide 2d of the liquid component detection system 1d according to the fifth embodiment. In the liquid component detection system 1g according to the eighth embodiment, both the infrared radiation source 3 and the light guide 2g are shared for forming a plurality (two) of infrared light paths 6.

  The light guide 2g has an incident prism 23g and an output prism 24g instead of the incident prism 23d and the output prism 24d of the light guide 2d.

  The incident prism 23g has a plurality of (two) incident surfaces 230g at which angles with respect to the first main surface 21 (angles with respect to a plane parallel to the first main surface 21) are different from each other and on which infrared rays from the infrared radiation source 3 are incident. . 9A to 9D, an angle of one of the two incident surfaces 230g (231g) with respect to the first main surface 21 is θ3, and an angle of the other incident surface 230g (232g) with respect to the first main surface 21 is two. θ4. Here, the incident prism 23g satisfies the relationship of θ3> θ4.

  The exit prism 24g has a plurality of (two) exit surfaces 240g that differ from each other in angle with respect to the first main surface 21 (angle with respect to a plane parallel to the first main surface 21) and emit infrared rays from the infrared radiation source 3. . The plurality of entrance surfaces 230g and the plurality of exit surfaces 240g correspond one-to-one, and the angles of the corresponding entrance surfaces 230g and exit surfaces 240g with respect to the first main surface 21 are the same. For this reason, in FIGS. 9A to 9D, the angle of one emission surface 240 g (241 g) of the two emission surfaces 240 g with respect to the first main surface 21 is set to θ3, and the other emission surface 240 g (242 g) is set to the first main surface 21. Is defined as θ4. Here, the exit prism 24g satisfies the relationship of θ3> θ4.

  In the liquid component detection system 1g, the two infrared light paths 6 include a first infrared light path 61 formed between the infrared radiation source 3 and the first light receiving element 41, and the infrared radiation source 3 and the second light receiving element 42. And a second infrared light path 62 formed between them. In the liquid component detection system 1g according to the eighth embodiment, the infrared light incident on the incident surface 231g of the incident prism 23g and the infrared light incident on the incident surface 232g of the incident prism 23g cause the light guide 2g and the liquid 10 to be in contact with each other. The period at which total reflection occurs at the interface is different. Thereby, in the liquid component detection system 1g according to the eighth embodiment, the optical path length of the first infrared optical path 61 and the optical path length of the second infrared optical path 62 can be made different.

  The liquid component detection system 1g according to the eighth embodiment has a plurality of infrared light paths 6 similarly to the liquid component detection system 1d according to the fifth embodiment. The plurality of infrared light paths 6 correspond to the plurality of light receiving elements 4 on a one-to-one basis, and pass through the input prism 23g and the output prism 24g, respectively. Both the infrared radiation source 3 and the light guide 2g are shared for forming a plurality of infrared light paths 6. Thus, the liquid component detection system 1g according to the eighth embodiment can detect a plurality of components of the liquid 10 while reducing the size.

(Embodiment 9)
Hereinafter, a liquid component detection system 1h according to the ninth embodiment will be described with reference to FIGS. Regarding the liquid component detection system 1h according to the ninth embodiment, the same components as those of the liquid component detection system 1g according to the eighth embodiment (see FIGS. 9A to 9D) are denoted by the same reference numerals and description thereof is omitted.

  The liquid component detection system 1h according to the ninth embodiment includes a light guide 2h instead of the light guide 2g of the liquid component detection system 1g according to the eighth embodiment. In the liquid component detection system 1h according to the ninth embodiment, both the infrared radiation source 3 and the light guide 2h are shared for forming a plurality (two) of infrared light paths 6.

  The light guide 2h has an input prism 23h and an output prism 24h instead of the input prism 23g and the output prism 24g of the light guide 2g. The entrance prism 23g and the exit prism 24g of the light guide 2g are convex portions protruding from the first main surface 21, whereas the entrance prism 23h and the exit prism 24h of the light guide 2h are the first prism. It is recessed from the main surface 21.

  The incident prism 23h has a plurality of (two) incident surfaces 230h at which angles with respect to the first main surface 21 (angles with respect to a plane parallel to the first main surface 21) are different from each other, and into which infrared rays from the infrared radiation source 3 are incident. . In FIG. 10B, the angle of one of the two incident surfaces 230h (231h) with respect to the first principal surface 21 is θ3h, and the angle of the other incident surface 230h (232h) with respect to the first principal surface 21 is θ4h. is there. Here, the incident prism 23h satisfies the relationship of θ3h ≠ θ4h. In the incident prism 23h, θ3h <θ4h.

  The exit prism 24h has a plurality of (two) exit surfaces 240h that differ in angle with respect to the first main surface 21 (angle with respect to a plane parallel to the first main surface 21) and emit infrared rays from the infrared radiation source 3. . The plurality of entrance surfaces 230h and the plurality of exit surfaces 240h correspond one-to-one, and the angles of the corresponding entrance surfaces 230h and exit surfaces 240h with respect to the first main surface 21 are the same. For this reason, in FIG. 10C, the angle of one of the emission surfaces 240h (241h) of the two emission surfaces 240h with respect to the first main surface 21 is set to θ3h, and the angle of the other emission surface 240h (242h) with respect to the first main surface 21 is set. Is set to θ4h. Here, the exit prism 24h satisfies the relationship of θ3h ≠ θ4h. In the emission prism 24h, θ3h <θ4h.

  In the liquid component detection system 1h according to the ninth embodiment, the two light receiving elements 4 are adjacent to each other in the second direction D2.

  In the liquid component detection system 1h according to the ninth embodiment, the two infrared light paths 6 include the first infrared light path 61 formed between the infrared radiation source 3 and the first light receiving element 41, and the infrared radiation source 3 and the second infrared light path. A second infrared light path 62 formed between the first light receiving element 42 and the second light receiving element 42. In the liquid component detection system 1h according to the ninth embodiment, the infrared light incident on the incident surface 231h of the incident prism 23h and the infrared light incident on the incident surface 232h of the incident prism 23h cause the light guide 2h and the liquid 10 to communicate with each other. The period at which total reflection occurs at the interface is different. Thus, in the liquid component detection system 1h according to the ninth embodiment, the optical path length of the first infrared optical path 61 and the optical path length of the second infrared optical path 62 can be made different.

  The liquid component detection system 1h according to the ninth embodiment detects a component of the liquid 10. The liquid component detection system 1h includes a light guide 2h, an infrared radiation source 3, and a plurality of light receiving elements 4. The light guide 2 h has a first main surface 21 in contact with the medium 9 and a second main surface 22 in contact with the liquid 10. The light guide 2h includes an incident prism 23h formed on the first main surface 21 and an emission prism 24h formed on the first main surface 21. The light guide 2h converts the infrared light incident on the incident prism 23h into total reflection at the interface between the second main surface 22 and the liquid 10 and total reflection at the interface between the first main surface 21 and the medium 9. The light is alternately and repeatedly guided to be emitted from the emission prism 24h. The infrared radiation source 3 radiates infrared light toward the incident prism 23h. The plurality of light receiving elements 4 receive the infrared light emitted from the emission prism 24h. In the liquid component detection system 1h, a plurality of infrared light paths 6 are formed. The plurality of infrared light paths 6 correspond to the plurality of light receiving elements 4 on a one-to-one basis, and pass through the input prism 23h and the output prism 24h. Both the infrared radiation source 3 and the light guide 2h are shared for forming a plurality of infrared light paths 6. Thus, in the liquid component detection system 1h according to the ninth embodiment, it is possible to detect a plurality of components of the liquid 10 while reducing the size.

  Further, in the liquid component detection system 1h according to the ninth embodiment, it is possible to detect a plurality of components of the liquid 10 using one incident prism 23h and one output prism 24h.

(Embodiment 10)
Hereinafter, a liquid component detection system 1i according to the tenth embodiment will be described with reference to FIGS. 11A to 11C. Regarding the liquid component detection system 1i according to the tenth embodiment, the same components as those of the liquid component detection system 1 according to the first embodiment (see FIGS. 1A and 2) are denoted by the same reference numerals and description thereof is omitted.

  A liquid component detection system 1i according to the tenth embodiment includes a light guide 2i instead of the light guide 2 of the liquid component detection system 1 according to the first embodiment. In the liquid component detection system 1i according to the tenth embodiment, both the infrared radiation source 3 and the light guide 2i are shared for forming a plurality (two) of infrared light paths 6.

  The light guide 2 i has one emission prism 24 instead of the two emission prisms 24 of the light guide 2.

  In the liquid component detection system 1i according to the tenth embodiment, a plurality (two) of the light receiving elements 4 are arranged in the third direction D3. The length of the emission prism 24 in the third direction D3 is determined so that the light guide 2i can emit infrared light from one emission prism 24 toward the two light receiving elements 4. In the liquid component detection system 1i according to the tenth embodiment, the length of the exit prism 24 in the third direction D3 is the same as the length of the entrance prism 23, but may be different.

  The liquid component detection system 1i according to the tenth embodiment further includes a reflection film 15. The reflection film 15 covers a part of the second main surface 22 of the light guide 2i. The reflection film 15 is located between the entrance prism 23 and the exit prism 24 when viewed from the thickness direction of the light guide 2i. The length of the reflection film 15 in the second direction D2 is shorter than the distance between the entrance prism 23 and the exit prism 24 in the second direction D2. The reflection film 15 reflects infrared light guided through one infrared light path 6 (second infrared light path 62) of the two infrared light paths 6. Accordingly, the number of times of total reflection at the interface between the light guide 2i and the liquid 10 can be reduced, so that the number of times that evanescent waves are absorbed by components of the liquid 10 can be reduced. In the infrared light path 6 (first infrared light path 61) shown in FIG. 11B and the infrared light path 6 (second infrared light path 62) shown in FIG. 11C, the number of total reflections of infrared light at the interface between the light guide 2i and the liquid 10 is performed. Are different. The material of the reflection film 15 is, for example, gold, aluminum, an aluminum alloy, or the like. The reflective film 15 has an absorptivity of the reflective film 15 for infrared light of a specific wavelength specific to the component of the liquid 10 to be detected, which is smaller than an absorptivity of infrared light (evanescent wave) of the specific wavelength for the component to be detected. The absorptance of the reflective film 15 is substantially zero, and ideally is zero.

  The liquid component detection system 1i according to the tenth embodiment detects a component of the liquid 10. The liquid component detection system 1i includes a light guide 2i, an infrared radiation source 3, and a plurality of light receiving elements 4. The light guide 2 i has a first main surface 21 in contact with the medium 9 and a second main surface 22 in contact with the liquid 10. The light guide 2 i has an incidence prism 23 formed on the first main surface 21 and an emission prism 24 formed on the first main surface 21. The light guide 2i converts the infrared light incident on the incident prism 23 into total reflection at the interface between the second main surface 22 and the liquid 10 and total reflection at the interface between the first main surface 21 and the medium 9. The light is guided alternately and repeatedly, and is emitted from the emission prism 24. The infrared radiation source 3 emits infrared light toward the incident prism 23. The plurality of (two) light receiving elements 4 receive the infrared light emitted from the emission prism 24. In the liquid component detection system 1h, a plurality (two) of infrared light paths 6 are formed. The plurality of infrared light paths 6 correspond to the plurality of light receiving elements 4 on a one-to-one basis, and pass through the incidence prism 23 and the emission prism 24, respectively. Both the infrared radiation source 3 and the light guide 2i are shared for forming a plurality of infrared light paths 6. Thus, in the liquid component detection system 1i according to the tenth embodiment, it is possible to detect a plurality of components of the liquid 10 while reducing the size.

  Further, since the liquid component detection system 1i according to the tenth embodiment includes the reflection film 15, it is possible to accurately detect a plurality of components of the liquid 10 even if the input prism 23 and the output prism 24 are each one. Can be.

  The reflective film 15 only needs to be disposed so as to reflect infrared light guided through at least one infrared light path 6 among the plurality of infrared light paths 6.

(Embodiment 11)
Hereinafter, a liquid component detection system 1j according to Embodiment 11 will be described with reference to FIGS. 12A and 12B. Regarding the liquid component detection system 1j according to the eleventh embodiment, the same components as those of the liquid component detection system 1 according to the first embodiment (see FIGS. 1A and 2) are denoted by the same reference numerals and description thereof is omitted.

  In the liquid component detection system 1j according to Embodiment 11, the light guide 2j is shared by a plurality (two) of infrared light paths 6. The liquid component detection system 1j includes a plurality (two) of infrared radiation sources 3. Hereinafter, one of the two infrared radiation sources 3 may be referred to as a first infrared radiation source 31 and the other may be referred to as a second infrared radiation source 32 for convenience of description. 12A and 12B are the same cross section. In FIG. 12A, one infrared light path 6 (first infrared light path 61) of the two infrared light paths 6 is shown by a broken line, and in FIG. The optical path 6 (second infrared optical path 62) is shown by a broken line.

  In the liquid component detection system 1j according to the eleventh embodiment, the incident angles of the infrared rays entering the incidence prism 23 from each of the two infrared radiation sources 3 are different from each other. Here, the two infrared radiation sources 3 are, as shown in FIG. 12A, an incident angle of the infrared ray incident on the incident surface 230 of the incident prism 23 from the first infrared radiation source 31 and a second infrared ray as shown in FIG. The incident angle of the infrared light incident on the incident surface 230 of the incident prism 23 from the radiation source 32 is different from the incident angle. The optical axis of the first infrared radiation source 31 is inclined with respect to the optical axis of the second infrared radiation source 32. The optical axis of the second infrared radiation source 32 is a direction parallel to the first direction D1.

  In the liquid component detection system 1j according to the eleventh embodiment, the emission angles of the infrared light emitted from the emission prism 24 to each of the plurality of light receiving elements 4 are different from each other. Here, as shown in FIG. 12A, the two light receiving elements 4 emit the infrared light from the first infrared radiation source 31 to the incident surface 230 of the incident prism 23 and exit from the exit surface 240 of the exit prism 24. As shown in FIG. 12B, the emission angle of the infrared light that enters the incident surface 230 of the incident prism 23 from the second infrared radiation source 32 and exits from the exit surface 240 of the exit prism 24 is different. The first light receiving element 41 of the two light receiving elements 4 is arranged to receive infrared light from the first infrared radiation source 31, and the second light receiving element 42 can receive infrared light from the second infrared radiation source 32. Are arranged as follows. The optical axis of the first light receiving element 41 is inclined with respect to the optical axis of the second light receiving element 42. The optical axis of the second light receiving element 42 is a direction parallel to the first direction D1.

  The liquid component detection system 1j according to the eleventh embodiment detects a component of the liquid 10. The liquid component detection system 1j includes a light guide 2j, an infrared radiation source 3, and a plurality of light receiving elements 4. The light guide 2 j has a first main surface 21 in contact with the medium 9 and a second main surface 22 in contact with the liquid 10. The light guide 2j has an incidence prism 23 formed on the first main surface 21 and an emission prism 24 formed on the first main surface 21. The light guide 2j converts the infrared light incident on the incident prism 23 into total reflection at the interface between the second main surface 22 and the liquid 10 and total reflection at the interface between the first main surface 21 and the medium 9. The light is guided alternately and repeatedly, and is emitted from the emission prism 24. The infrared radiation source 3 emits infrared light toward the incident prism 23. The plurality of (two) light receiving elements 4 receive the infrared light emitted from the emission prism 24. In the liquid component detection system 1j, a plurality (two) of infrared light paths 6 are formed. The plurality of infrared light paths 6 correspond to the plurality of light receiving elements 4 on a one-to-one basis, and pass through the incidence prism 23 and the emission prism 24, respectively. The light guide 2j is shared for forming a plurality of infrared light paths 6. Thus, the liquid component detection system 1j according to the eleventh embodiment can detect a plurality of components of the liquid 10 while reducing the size.

  In the liquid component detection system 1j according to the eleventh embodiment, each of the plurality of infrared radiation sources 3 includes an infrared radiation element that emits infrared light by thermal radiation. However, the present invention is not limited to this. Instead of the infrared radiation element, An infrared light emitting diode may be included. In this case, for example, the plurality of infrared radiation sources 3 only need to include infrared light emitting diodes whose emission peak wavelengths are different from each other.

(Modification)
The above embodiments are merely one of various embodiments of the present invention. The above embodiment can be variously modified according to the design and the like as long as the object of the present invention can be achieved.

  For example, the liquid 10 is not limited to gasoline, but may be, for example, water, soft drink, or the like.

  Further, instead of the processing circuit of the liquid component detection system 1b according to the third embodiment, a processing circuit (component detection circuit) 8k having a configuration shown in FIG. 13 may be employed.

  The processing circuit 8k includes a signal processing unit 81, a control unit 82, a multiplexer 83, and a drive circuit 84.

  The signal processing unit 81 includes a first current-voltage conversion circuit 811 (also referred to as a first I / V conversion circuit 811), a second current-voltage conversion circuit 812 (also referred to as a second I / V conversion circuit 812), and a first amplification circuit. 813, a second amplifier circuit 814, and a subtractor 815. In addition, the signal processing unit 81 further includes a low-pass filter 816, an A / D conversion circuit 817, and a calculation unit 818. In the processing circuit 8k, the temperature sensor 85 is connected to the signal processing unit 81, but the temperature sensor 85 is not an essential component. The temperature sensor 85 measures, for example, the temperature of the liquid 10 and outputs an analog output signal corresponding to the measured temperature.

  The first I / V conversion circuit 811 is, for example, a TIA (Trans Impedance Amplifier) and converts a current signal into a voltage signal. The first I / V conversion circuit 811 receives a current signal which is an output signal of the fourth light receiving element 44 that receives infrared light having a reference wavelength transmitted through the fourth optical filter 54. That is, the first I / V conversion circuit 811 converts the current signal, which is the output signal of the fourth light receiving element 44, into a voltage signal and outputs the voltage signal to the first amplifier circuit 813.

  The second I / V conversion circuit 812 is, for example, a TIA, and converts a current signal into a voltage signal. The output signals of the first to third light receiving elements 41 to 43 are input to the second I / V conversion circuit 812 via the multiplexer 83. The multiplexer 83 selectively inputs the output signals of the first to third light receiving elements 41 to 43 to the second I / V conversion circuit 812. Therefore, the output signal of any one of the first to third light receiving elements 41 to 43 is input to the second I / V conversion circuit 812. The second I / V conversion circuit 812 converts a current signal, which is an output signal of any one of the first to third light receiving elements 41 to 43, into a voltage signal and outputs the voltage signal to the second amplifier circuit 814. .

  The first amplifier circuit 813 is, for example, a PGA (Programmable Gain Amplifier), and amplifies the output signal of the first I / V conversion circuit 811 and outputs the amplified signal to the subtracter 815.

  The second amplifier circuit 814 is, for example, a PGA, and amplifies the output signal of the second I / V conversion circuit 812 and outputs the amplified signal to the subtractor 815.

  The subtractor 815 is, for example, a differential amplifier, and outputs an output signal proportional to the difference between the output signal of the first amplifier circuit 813 and the output signal of the second amplifier circuit 814.

  The low-pass filter 816 attenuates a frequency component equal to or higher than a predetermined frequency from the output signal of the subtractor 815. The signal processing unit 81 can reduce noise of the output signal of the subtractor 815 by the low-pass filter 816.

  The A / D conversion circuit 817 performs analog-to-digital conversion of an analog output signal of the subtracter 815 input via the low-pass filter 816, and outputs a digital output signal to the arithmetic unit 818. The output signal of the temperature sensor 85 is input to the A / D conversion circuit 817. The A / D conversion circuit 817 performs analog-to-digital conversion on the output signal of the temperature sensor 85 and outputs the signal to the arithmetic unit 818.

  The arithmetic unit 818 mainly has a microcontroller having a processor and a memory, and executes a program stored in the memory by the processor to realize a function as the arithmetic unit. The program may be recorded in a memory in advance, may be provided through an electric communication line such as the Internet, or may be recorded in a recording medium such as a memory card and provided.

  The calculation unit 818 calculates the concentration of the detection target component contained in the liquid 10 based on the output signal of the subtractor 815 digitized by the A / D conversion circuit 817. Specifically, the calculation unit 818 determines the first value of the liquid 10 based on the output signal of the A / D conversion circuit 817 according to the difference between the output signal of the fourth light receiving element 44 and the output signal of the first light receiving element 41. Calculate the concentration of the component. Further, the arithmetic unit 818 calculates the concentration of the second component of the liquid 10 based on the output signal of the A / D conversion circuit 817 according to the difference between the output signal of the fourth light receiving element 44 and the output signal of the second light receiving element 42. Is calculated. The calculating unit 818 also calculates the concentration of the third component of the liquid 10 based on the output signal of the A / D conversion circuit 817 according to the difference between the output signal of the fourth light receiving element 44 and the output signal of the third light receiving element 43. Is calculated. The processing circuit 8k may include an output unit that outputs the calculation result (density) of the calculation unit 818 to the outside.

  In addition, although the calculation unit 818 is configured to correct the density of the calculation result based on the output signal of the temperature sensor 85, the correction of the density by the calculation unit 818 is not essential.

  The control unit 82 mainly includes a microcontroller having a processor and a memory, and executes a program stored in the memory by the processor, so that the control unit 82 functions as the light source control unit 821, the selection unit 822, and the drive setting unit 823. Realize. The program may be recorded in a memory in advance, may be provided through an electric communication line such as the Internet, or may be recorded in a recording medium such as a memory card and provided.

  The light source control unit 821 drives the infrared radiation source 3 by the drive circuit 84 by controlling the drive circuit 84. The drive circuit 84 drives the infrared radiation source 3 based on a light source control signal from the light source control unit 821. The light source control unit 821 controls the drive circuit 84 so that the infrared radiation source 3 is intermittently driven. Each time the infrared radiation source 3 is driven, the above-described signal processing unit 81 calculates the concentration of any one of a plurality of components to be detected contained in the liquid 10.

  The selector 822 selects the light receiving element 4 to be connected to the second I / V conversion circuit 812 among the first light receiving element 41 to the third light receiving element 43. The selection unit 822 controls the multiplexer 83 so that the selected light receiving element 4 is connected to the second I / V conversion circuit 812. The calculating unit 818 determines the liquid 10 corresponding to the light receiving element 4 selected by the selecting unit 822 based on the output signal of the fourth light receiving element 44 and the output signal of the light receiving element 4 selected by the selecting unit 822. Calculate the concentration of the component.

  Further, the selection unit 822 changes the light receiving element 4 to be connected to the second I / V conversion circuit 812 among the first light receiving element 41 to the third light receiving element 43 over time. For example, the selection unit 822 repeatedly selects the first light receiving element 41, the second light receiving element 42, and the third light receiving element 43 in this order over time. Therefore, the signal processing unit 81 performs time-division processing of the signal processing on the output signal of the first light receiving element 41, the signal processing on the output signal of the second light receiving element 42, and the signal processing on the output signal of the third light receiving element 43. Can be done with Thus, one signal processing unit 81 can calculate the density of each of the first component, the second component, and the third component.

  The selection unit 822 selects the light receiving element 4 such that the light receiving element 4 connected to the second I / V conversion circuit 812 switches every time the infrared radiation source 3 is driven once, but is not limited thereto. For example, the selection unit 822 selects the light receiving element 4 such that the light receiving element 4 connected to the second I / V conversion circuit 812 switches every time the infrared radiation source 3 is driven n times (n is an integer of 2 or more). May be. In this case, the calculation unit 818 may cause the output unit to output the average value of the results of the n density calculations.

  In the processing circuit 8k, a circuit for performing signal processing on the output signals of the first to third light receiving elements 41 to 43 is shared, and the signal processing is performed in a time-division manner. (1st component to 3rd component) are detected. Thereby, in the processing circuit 8k, it is possible to reduce the number of components, reduce power consumption, and the like, as compared with the case where a processing circuit is provided for each of a plurality of components.

  Further, the processing circuit 8k includes a drive setting unit 823 for setting drive conditions of the infrared radiation source 3. The driving condition of the infrared radiation source 3 is a driving voltage applied to the infrared radiation element of the infrared radiation source 3. As the driving voltage of the infrared radiation source 3 increases, the radiation intensity of the infrared radiation increases. The light source control unit 821 controls the drive circuit 84 based on the drive conditions set by the drive setting unit 823. That is, the light source control unit 821 controls the drive circuit 84 so that the drive voltage set by the drive setting unit 823 is applied to the infrared radiation source 3.

  The drive setting unit 823 determines that the level difference between the output signals of the first to third light receiving elements 41 to 43 is equal to or less than a predetermined value when the density of the detection target component (first to third components) is lower than the specific density. Drive conditions are set as described above. The specific concentration is, for example, 0%, 10%, 20%, or the like. The drive setting unit 823 sets the driving conditions (driving voltage) of the infrared radiation source 3 corresponding to each of the first to third components to be detected, so that the outputs of the first to third light receiving elements 41 to 43 are set. The signal level difference is set to a predetermined value or less. Driving conditions (driving voltage) corresponding to each of the first to third components to be detected are predetermined and stored in a memory.

  The drive setting unit 823 refers to the memory and sets driving conditions corresponding to the light receiving element 4 selected by the selecting unit 822 among the first to third light receiving elements 41 to 43. The light source control unit 821 controls the driving circuit so that the infrared radiation source 3 is driven under the driving conditions set by the driving setting unit 823.

  Since the drive conditions are set in the drive setting unit 823 as described above, the processing circuit 8k can accurately detect each of the plurality of components of the liquid 10 and can suppress variations in detection accuracy. It becomes.

  Further, in the above-described example, the signal processing unit 81 determines the difference between the output signal of the fourth light receiving element 44 and the output signal of any one of the first to third light receiving elements 41 to 43. Although the detection target component has been detected, the present invention is not limited to this. The signal processing section 81 detects a component to be detected based on a ratio between an output signal of the fourth light receiving element 44 and an output signal of any one of the first to third light receiving elements 41 to 43. May be. In addition, the signal processing unit 81 may detect a component to be detected based only on output signals of the first to third light receiving elements 41 to 43.

  In the processing circuit 8k, the second I / V conversion circuit 812 may be configured so that the amplification factor of the second I / V conversion circuit 812 can be configured. In this case, the output signal after the amplification of the output signal of the fourth light receiving element 44 and the output signal after the amplification of the output signal of each of the first light receiving element 41 to the third light receiving element 43 when the concentration of the component to be detected is 0%. The amplification factor of the second I / V conversion circuit 812 may be changed so that the difference from the output signal is smaller than a predetermined value. In this case, the second I / V conversion circuit 812 includes, for example, an operational amplifier and a variable resistance circuit connected between the inverting input terminal and the output terminal of the operational amplifier. The variable resistance circuit includes, for example, a plurality of series circuits of a switch and a resistance, and the plurality of serial circuits are connected in parallel, and the control unit 82 controls ON / OFF of each switch of the variable resistance circuit.

(Summary)
The following aspects are disclosed from the embodiments and the like described above.

  The liquid component detection system (1; 1a; 1b; 1c; 1d; 1e; 1f; 1g; 1h; 1i; 1j) according to the first embodiment detects a component of a liquid (10). The liquid component detection system (1; 1a; 1b; 1c; 1d; 1e; 1f; 1g; 1h; 1i; 1j) comprises a light guide (2; 2a; 2b; 2c; 2d; 2e; 2f; 2g; 2i; 2j), an infrared radiation source (3), and a plurality of light receiving elements (4). The light guide (2; 2a; 2b; 2c; 2d; 2e; 2f; 2g; 2h; 2i; 2j) has a first main surface (21) in contact with the medium (9) and a second main surface in contact with the liquid (10). It has a main surface (22). The light guide (2) has an incidence prism (23) formed on the first main surface (21) and an emission prism (24) formed on the first main surface (21). The light guide (2; 2a; 2b; 2c; 2d; 2e; 2f; 2g; 2h; 2i; 2j) enters the incidence prism (23; 23b; 23c; 23d; 23e; 23f; 23g; 23h). The infrared rays thus obtained are alternately and repeatedly subjected to total reflection at the interface between the second main surface (22) and the liquid (10) and total reflection at the interface between the first main surface (21) and the medium (9). The light is guided and emitted from the emission prism (24; 24c; 24d; 24e; 24f; 24g; 24h). The infrared radiation source (3) radiates infrared rays toward the incident prisms (23; 23b; 23c; 23d; 23e; 23f; 23g; 23h). The plurality of light receiving elements (4) receive infrared rays emitted from the emission prisms (24; 24c; 24d; 24e; 24f; 24g; 24h). In the liquid component detection system (1; 1a; 1b; 1c; 1d; 1e; 1f; 1g; 1h; 1i; 1j), a plurality of infrared light paths (6) are formed. The plurality of infrared light paths (6) correspond to the plurality of light receiving elements (4) in a one-to-one correspondence, and each of the incident prism (23; 23b; 23c; 23d; 23e; 23f; 23g; 24c; 24d; 24e; 24f; 24g; 24h). At least one of the infrared radiation source (3) and the light guide (2; 2a; 2b; 2c; 2d; 2e; 2f; 2g; 2h; 2i; 2j) is used to form a plurality of infrared light paths (6). Have been.

  In the liquid component detection system (1; 1a; 1b; 1c; 1d; 1e; 1f; 1g; 1h; 1i; 1j) according to the first embodiment, a plurality of components of the liquid (10) are detected while miniaturizing the system. It is possible to do.

  In the liquid component detection system (1; 1a; 1b; 1c) according to the second embodiment, a plurality of exit prisms (24; 24c) are provided in the first embodiment. Both the infrared radiation source (3) and the light guide (2; 2a; 2b; 2c) are shared to form a plurality of infrared light paths (6). The plurality of exit prisms (24; 24c) include a first exit prism (241) and a second exit prism (242). The distance between the entrance prism (23; 23b; 23c) and the first exit prism (241) is longer than the distance between the entrance prism (23; 23b; 23c) and the second exit prism (242).

  In the liquid component detection system (1; 1a; 1b; 1c) according to the second aspect, the detection accuracy of a plurality of components having different absorbances can be improved.

  In the liquid component detection system (1) according to the third aspect, in the second aspect, the first exit prism (241) and the second exit prism (242) are viewed from the entrance prism (23). Located on the same side.

  In the liquid component detection system (1) according to the third aspect, the size of the light guide (2) can be reduced.

  In the liquid component detection system (1a; 1b) according to the fourth aspect, in the second aspect, the first exit prism (241) and the second exit prism (242) are separated from the entrance prism (23). They are located on opposite sides of each other.

  In the liquid component detection system (1a; 1b) according to the fourth aspect, the area of the exit surface (240) of each of the first exit prism (241) and the second exit prism (242) can be increased. And the detection accuracy of each component can be improved.

  In the liquid component detection system (1b) according to the fifth aspect, in the fourth aspect, the plurality of exit prisms (24) include a third exit prism (243) and a fourth exit prism (244). . The third exit prism (243) and the fourth exit prism (244) are located on opposite sides of the entrance prism (23b). The direction in which the first emission prism (241) and the second emission prism (242) are arranged crosses the direction in which the third emission prism (243) and the fourth emission prism (244) are arranged. I do.

  In the liquid component detection system (1b) according to the fifth aspect, four components of the liquid (10) can be detected.

  In the liquid component detection system (1c) according to the sixth aspect, in the first aspect, both the infrared radiation source (3) and the light guide (2c) are shared for forming a plurality of infrared light paths (6). Have been. The liquid component detection system (1c) includes five or more exit prisms (24c). The incidence prism (23c) has a conical or truncated conical shape. Five or more exit prisms (24c) are arranged so as to surround the entrance prism (23c).

  In the liquid component detection system (1c) according to the sixth aspect, it is possible to detect more components of the liquid (10).

  In the liquid component detection system (1d; 1e; 1f; 1g; 1h) according to the seventh aspect, in the first aspect, the infrared radiation source (3) and the light guide (2d; 2e; 2f; 2g; 2h). Are shared by a plurality of infrared light paths (6). The incident prisms (23d; 23e; 23f; 23g; 23h) have different angles with respect to the first main surface (21) and a plurality of incident surfaces (230d; 230e; 230f) on which infrared rays from the infrared radiation source (3) are incident. 230g; 230h). The exit prisms (24d; 24e; 24f; 24g; 24h) have a plurality of exit surfaces (240d; 240e; 240f) which differ in angle with respect to the first main surface (21) and emit infrared rays from the infrared radiation source (3). 240g; 240h). The plurality of incident surfaces (230d; 230e; 230f; 230g; 230h) and the plurality of exit surfaces (240d; 240e; 240f; 240g; 240h) correspond one-to-one, and the corresponding incident surfaces (230d; 230e; 230f; 230g; 230h) and the exit surface (240d; 240e; 240f; 240g; 240h) have the same angle with respect to the first main surface (21).

  In the liquid component detection system (1d; 1e; 1f; 1g; 1h) according to the seventh aspect, one incident prism (23d; 23e; 23f; 23g; 23h) and one exit prism (24d; 24e; 24f; 24g; 24h) to detect a plurality of components of the liquid (10).

  In a liquid component detection system (1i) according to an eighth aspect, in the first aspect, both the infrared radiation source (3) and the light guide (2i) are shared by a plurality of infrared light paths (6). I have. The liquid component detection system (1i) further includes a reflection film (15). The reflection film (15) covers a part of the second main surface (22) of the light guide (2i), and at least one of the plurality of infrared light paths (6) (second infrared light path 62). The light that is guided reflects the infrared light.

  In the liquid component detection system (1i) according to the eighth aspect, a plurality of components of the liquid (10) can be detected with high accuracy even if the incidence prism (23) and the emission prism (24) are each one. .

  In a liquid component detection system (1j) according to a ninth aspect, in the first aspect, the light guide (2j) is shared by a plurality of infrared light paths (6). The liquid component detection system (1j) includes a plurality of infrared radiation sources (3). The incident angles of the infrared rays incident on the incidence prism (23) from each of the plurality of infrared radiation sources (3) are different from each other. The emission angles of the infrared light emitted from the emission prism (24) to each of the plurality of light receiving elements (4) are different from each other.

  The liquid component detection system (1j) according to the ninth aspect can accurately detect a plurality of components of the liquid (10).

  In the liquid component detection system (1; 1a; 1b; 1c; 1d; 1e; 1f; 1g; 1h; 1i; 1j) according to the tenth aspect, in the first aspect, each of the plurality of light receiving elements (4) The different components of the liquid (10) are detected from the output signal of.

  In the liquid component detection system (1; 1a; 1b; 1c; 1d; 1e; 1f; 1g; 1h; 1i; 1j) according to the tenth aspect, it is possible to accurately detect a plurality of components of the liquid (10). It becomes possible.

  In the liquid component detection system (1; 1a; 1b; 1c; 1d; 1g; 1i; 1j) according to the eleventh aspect, in any one of the first to tenth aspects, the incident prism (23; 23b; 23c; 23d; 23g) and the exit prism (24; 24c; 24d; 24g) each include a first main surface (21) of the light guide (2; 2a; 2b; 2c; 2d; 2g; 2i; 2j). ).

  In the liquid component detection system (1; 1a; 1b; 1c; 1d; 1g; 1i; 1j) according to the eleventh aspect, the light guide (2; 2a; 2b; 2c; 2d; 2g; 2i; 2j) The distance between the first main surface (21) and the second main surface (22) can be reduced, the number of times that infrared rays are totally reflected can be increased, and each of the liquids (10) can be The component detection accuracy can be further improved.

  The liquid component detection system (1; 1a; 1b; 1c; 1d; 1e; 1f; 1g; 1h; 1i; 1j) according to the twelfth aspect is directed to any one of the first to twelfth aspects. It further includes a processing circuit (8) for performing signal processing on each output signal of the light receiving element (4).

  In the liquid component detection system (1; 1a; 1b; 1c; 1d; 1e; 1f; 1g; 1h; 1i; 1j) according to the twelfth aspect, each component of the liquid (10) can be detected with higher accuracy. it can.

  The liquid component detection system (1; 1a; 1b; 1c; 1d; 1e; 1f; 1g; 1h; 1i; 1j) according to the thirteenth aspect provides the liquid component detection system according to any one of the first to thirteenth aspects. It further comprises a pipe (7) through which 10) passes. The pipe (7) has an opening (73) between the inlet (71) and the outlet (72) for the liquid (10). The light guides (2; 2a; 2b; 2c; 2d; 2e; 2f; 2g; 2h; 2i; 2j) are arranged so as to cover the openings (73).

  In the liquid component detection system (1; 1a; 1b; 1c; 1d; 1e; 1f; 1g; 1h; 1i; 1j) according to the thirteenth aspect, the liquid (10) flowing through the pipe (7) is It becomes possible to detect a plurality of components.

1, 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j Liquid component detection system 2, 2a, 2b, 2c, 2d, 2e, 2f, 2g, 2h, 2i, 2j Light guide 21 First principal surface 22 Second principal surface 23, 23b, 23c, 23d, 23e, 23f, 23g, 23h Incident prism 230d, 230e, 230f, 230g, 230h Incident surface 24, 24c, 24d, 24e, 24f, 24g, 24h Outgoing prism 240d, 240e, 240f, 240g, 240h Outgoing surface 241 First outgoing prism 242 Second outgoing prism 243 Third outgoing prism 244 Fourth outgoing prism 3 Infrared radiation source 4 Light receiving element 5 Optical filter 6 Infrared light path 7 Pipe 71 Inlet 72 Outlet 73 Opening 8 Processing circuit 9 Medium 10 Liquid D1 First Direction D2 the second direction D3 the third direction

Claims (13)

A liquid component detection system that detects a component of a liquid,
It has a first main surface in contact with a medium and a second main surface in contact with the liquid, and has an incident prism formed on the first main surface and an emission prism formed on the first main surface. Then, the infrared ray incident on the incidence prism is alternately and repeatedly subjected to total reflection at an interface between the second main surface and the liquid and total reflection at an interface between the first main surface and the medium. A light guide that guides light and exits from the exit prism;
An infrared radiation source that emits infrared radiation toward the incident prism,
A plurality of light receiving elements for receiving infrared light emitted from the emission prism,
Corresponding to the plurality of light receiving elements in a one-to-one manner, a plurality of infrared light paths are formed, each passing through the incidence prism and the emission prism,
At least one of the infrared radiation source and the light guide is shared to form the plurality of infrared light paths,
Liquid component detection system. A plurality of the exit prisms,
Both the infrared radiation source and the light guide are shared to form the plurality of infrared light paths,
The plurality of exit prisms include a first exit prism and a second exit prism,
The distance between the incident prism and the first output prism is longer than the distance between the incident prism and the second output prism.
The liquid component detection system according to claim 1. The first exit prism and the second exit prism are located on the same side as viewed from the entrance prism,
The liquid component detection system according to claim 2. The first exit prism and the second exit prism are located on opposite sides of the entrance prism.
The liquid component detection system according to claim 2. The plurality of exit prisms further include a third exit prism and a fourth exit prism,
The third exit prism and the fourth exit prism are located on opposite sides of the entrance prism,
The direction in which the first emission prism and the second emission prism are arranged intersects with the direction in which the third emission prism and the fourth emission prism are arranged.
The liquid component detection system according to claim 4. Both the infrared radiation source and the light guide are shared to form the plurality of infrared light paths,
Comprising five or more exit prisms;
The incidence prism has a conical or truncated cone shape,
The five or more exit prisms are arranged so as to surround the entrance prism.
The liquid component detection system according to claim 1. Both the infrared radiation source and the light guide are shared to form the plurality of infrared light paths,
The incidence prism has a plurality of incidence surfaces on which infrared rays from the infrared radiation source are incident at different angles with respect to the first main surface,
The emission prism has a plurality of emission surfaces that emit infrared rays from the infrared radiation source at different angles with respect to the first main surface,
The plurality of entrance surfaces and the plurality of exit surfaces correspond one-to-one, and the corresponding entrance surface and exit surface have the same angle with respect to the first main surface.
The liquid component detection system according to claim 1. Both the infrared radiation source and the light guide are shared by the plurality of infrared light paths,
The light guide further includes a reflective film that covers a part of the second main surface and reflects infrared light guided through at least one infrared light path among the plurality of infrared light paths.
The liquid component detection system according to claim 1. The light guide is shared by the plurality of infrared light paths,
Comprising a plurality of the infrared radiation sources,
The incident angles of infrared rays incident on the prism for incidence from each of the plurality of infrared radiation sources are different from each other,
The emission angles of infrared rays emitted from the emission prism to each of the plurality of light receiving elements are different from each other,
The liquid component detection system according to claim 1. Detecting mutually different components of the liquid from output signals of each of the plurality of light receiving elements,
The liquid component detection system according to claim 1. Each of the incidence prism and the emission prism protrudes from the first main surface of the light guide,
The liquid component detection system according to claim 1. Further comprising a processing circuit for signal processing the output signal of each of the plurality of light receiving elements,
A liquid component detection system according to claim 1. Further comprising a pipe through which the liquid passes;
The pipe has an opening between an inlet and an outlet of the liquid,
The light guide is arranged to cover the opening,
The liquid component detection system according to claim 1.

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