Optical concentration measuring device

Abstract

Provided is an optical concentration measurement instrument for measuring the concentration of a target component in a gas, the optical concentration measurement instrument being provided with: an acoustic cavity having a gas introduction port and accommodating the gas introduced through the gas introduction port; the optical component is arranged in the acoustic cavity; and an acoustic transducer provided in the acoustic cavity, the optical member having one or more light sources that emit light having a wavelength absorbed by the target component, and one or more optical waveguides that are optically connected to the light sources, the light from the light sources propagating inside the optical waveguides, and the acoustic transducer being disposed in the acoustic cavity. And at least one part of the optical waveguide is exposed to the space in the acoustic cavity.

Description

Technical Field

[0001] This invention relates to an optical concentration measuring device. Background Technology

[0002] Patent document 1 states that "as Figure 1 As shown, the proposed photoacoustic gas sensor device can be constructed with a small form factor, resulting in an overall size of, for example, 1 × 1 × 0.7 cm. 3 "(0040)

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: US2022 / 0187193A1 Summary of the Invention

[0006] In a first embodiment, an optical concentration meter is provided for measuring the concentration of a target component in a gas. The optical concentration meter includes: a acoustic cavity having a gas inlet for receiving the gas introduced through the gas inlet; an optical component disposed within the acoustic cavity; and a sound transducer disposed within the acoustic cavity. The optical component has one or more light sources and one or more optical waveguides. The light sources emit light containing wavelengths absorbed by the target component. The optical waveguides are optically connected to the light sources, and the light from the light sources propagates within the optical waveguides. At least a portion of the optical waveguides is exposed into the space within the acoustic cavity.

[0007] In the aforementioned optical concentration measuring device, the sound transducer may output an electrical signal corresponding to the pressure change within the acoustic cavity. The pressure change within the acoustic cavity is generated by causing the target component contained in the gas, which exists around the optical waveguide and has a refractive index smaller than the optical waveguide, to absorb evanescent waves. These evanescent waves leak out to the outside of the optical waveguide as the light from the light source propagates within the optical waveguide.

[0008] Any of the above optical concentration measuring devices can have a 10mm 3 The following volume. In the above-mentioned optical concentration measuring device, the effective optical path length of the optical waveguide may also be 10 mm or more.

[0009] In the aforementioned optical concentration measuring device, the optical component may have one or more substrates, which support the light source and the optical waveguide.

[0010] In the aforementioned optical concentration measuring device, the light source and the optical waveguide may also be disposed on a substrate and in direct contact with each other.

[0011] In the aforementioned optical concentration measuring device, the light source and the optical waveguide may both be disposed on a single substrate and optically coupled to each other via an optical coupler.

[0012] In the aforementioned optical concentration measuring device, the light source and the optical waveguide may be respectively disposed on different substrates and optically coupled to each other via an optical coupler.

[0013] In any of the aforementioned optical concentration measuring devices, at least a portion of the optical waveguide in the direction of light propagation within the optical waveguide may not contact the substrate, but rather the entire surface may be exposed to the space within the acoustic cavity.

[0014] In any of the optical concentration measuring devices described above, a space may be provided between the light source and the substrate.

[0015] In the aforementioned optical concentration measuring device, the optical waveguide may also include at least a partial bend that bends the propagation direction of the light propagating within the optical waveguide.

[0016] In the aforementioned optical concentration measuring device, the optical waveguide may also include at least one or more pairs of reflective elements, which restore the propagation direction of the light propagating within the optical waveguide after reversal.

[0017] In the aforementioned optical concentration measuring device, the optical waveguide may also include at least a partial elliptical surround portion, which causes the light propagating within the optical waveguide to surround an ellipse.

[0018] In the aforementioned optical concentration measuring device, the optical waveguide may also include at least a partial annular surrounding portion, which causes the light propagating within the optical waveguide to circulate on an ellipse or a circle.

[0019] In the aforementioned optical concentration measuring device, the optical component may also include a photodetector for detecting light from the light source. In any of the aforementioned optical concentration measuring devices, the light source may also adjust the output of the emitted light based on the detection result of the photodetector.

[0020] In the aforementioned optical concentration measuring device, the optical component may also have an optical filter that allows light of the specified wavelength from the light source to pass through and cuts off light of other wavelengths.

[0021] In the aforementioned optical concentration measuring device, the optical component may also have a plurality of optical waveguides optically connected to one of the light sources.

[0022] In the aforementioned optical concentration measuring device, the optical component may also have a plurality of light sources optically connected to one or more of the optical waveguides.

[0023] In any of the optical concentration measuring devices described above, the average optical path length of the light from the light source that does not enter the optical waveguide but is radiated into the space within the acoustic cavity and reflected by the inner wall of the acoustic cavity is shorter than the effective optical path length of the optical waveguide.

[0024] In any of the optical concentration measuring devices mentioned above, the average reflectivity of the inner wall of the acoustic cavity may be less than 70%.

[0025] In any of the aforementioned optical concentration measuring devices, the acoustic cavity may have a base portion, on which the optical components and the acoustic transducer are disposed. Alternatively, the acoustic cavity may have a cover portion, on which the gas inlet is formed and mounted on the base portion.

[0026] In any of the aforementioned optical concentration measuring devices, the cover may be adhered to the base, so that the internal space of the acoustic cavity is connected to the external space of the acoustic cavity only through the gas inlet.

[0027] In the aforementioned optical concentration measuring device, the base portion may also have a conductive portion. In the aforementioned optical concentration measuring device, the conductive portion may also include an inner contact end formed on the surface and electrically connected to at least one of the light source and the sound transducer. In any of the aforementioned optical concentration measuring devices, the conductive portion may also include an outer contact end exposed to the external space of the acoustic cavity.

[0028] Any of the aforementioned optical concentration measuring devices may also be equipped with a dust filter, which is installed at the gas inlet to seal the gas contained within the acoustic cavity.

[0029] Any of the aforementioned optical concentration measuring devices may also include a circuit, which is disposed within the acoustic cavity and electrically connected to at least one of the light source and the sound transducer.

[0030] The above summary of the invention does not list all the features of the invention. Sub-combinations of these feature groups can also constitute inventions. Attached Figure Description

[0031] Figure 1 This is a schematic side view of an embodiment of an optical concentration measuring device 100.

[0032] Figure 2 yes Figure 1 A schematic top view of the optical concentration measuring device 100 shown.

[0033] Figure 3 This is a schematic side view of an optical component 220 according to one embodiment.

[0034] Figure 4 This is a schematic side view of an embodiment of an optical concentration measuring device 300.

[0035] Figure 5 This is a schematic side view of an optical component 321 according to one embodiment.

[0036] Figure 6 This is a schematic side view of an optical component 322 according to one embodiment.

[0037] Figure 7 This is a schematic side view of an optical component 323 according to one embodiment.

[0038] Figure 8 This is a schematic side view of an embodiment of an optical concentration measuring device 400.

[0039] Figure 9 This is a schematic side view of an embodiment of an optical concentration measuring device 401.

[0040] Figure 10 This is a schematic side view of an embodiment of an optical concentration measuring device 402.

[0041] Figure 11 This is a schematic side view of an embodiment of an optical concentration measuring device 500.

[0042] Figure 12 This is a schematic side view of an embodiment of an optical concentration measuring device 600.

[0043] Figure 13 This is a schematic side view of an optical component 621 according to one embodiment.

[0044] Figure 14 This is a schematic side view of an optical component 622 according to one embodiment.

[0045] Figure 15 This is a schematic top view of an embodiment of an optical waveguide 741.

[0046] Figure 16 This is a schematic top view of an embodiment of an optical waveguide 742.

[0047] Figure 17 This is a schematic top view of an embodiment of an optical waveguide 743.

[0048] Figure 18This is a schematic side view of the optical waveguide 840 and the light source 130 of an optical component 820 according to one embodiment.

[0049] Figure 19 This is a schematic top view of an optical component 920 according to one embodiment.

[0050] Figure 20 This is a schematic top view of an optical component 921 according to one embodiment.

[0051] Figure 21 yes Figure 20 A schematic side view of the optical component 921 shown.

[0052] Figure 22 This is a schematic top view of an optical component 1021 according to one embodiment.

[0053] Figure 23 This is a schematic top view of the optical waveguide 1140 and the light source 130 of the optical component 1120 in one embodiment.

[0054] Figure 24 This is a schematic top view of the optical waveguide 1240 and the light source 130 of the optical component 1220 in one embodiment.

[0055] Figure 25 This is a schematic top view of an embodiment of an optical concentration measuring device 1300.

[0056] Figure 26 yes Figure 25 A schematic side view of the optical concentration meter 1300 shown.

[0057] Figure 27 This is a schematic top view of an embodiment of an optical concentration measuring device 1400.

[0058] Figure 28 yes Figure 27 A schematic side view of the optical concentration meter 1400 shown.

[0059] Figure 29 This is a schematic top view of an optical component 1520 according to one embodiment.

[0060] Figure 30 This is a schematic top view of an optical component 1620 according to one embodiment.

[0061] Figure 31 yes Figure 30 A schematic side view of the optical component 1620 shown.

[0062] Figure 32 This is a schematic top view of an embodiment of an optical concentration measuring device 1800.

[0063] Figure 33 This is a schematic top view of the optical filter 1881, the light source 1831, and the optical waveguide 140 of an optical component 1821 according to one embodiment.

[0064] Figure 34 This is a schematic top view of the optical filter 1882, the light source 1832, and the optical waveguide 140 of an optical component 1822 according to one embodiment.

[0065] Figure 35 This is a schematic top view of the optical filter 1883, the light source 1833, and the optical waveguide 140 of an optical component 1823 according to one embodiment.

[0066] Figure 36 This is a schematic top view of an embodiment of an optical concentration measuring device 1900.

[0067] Figure 37 This is a schematic top view of an embodiment of an optical concentration measuring device 1901.

[0068] Figure 38 This is a schematic top view of an embodiment of an optical concentration measuring device 2000.

[0069] Figure 39 This is a schematic top view of an embodiment of an optical concentration measuring device 2001.

[0070] Figure 40 yes Figure 6 A schematic side view of the optical concentration measuring device 600 shown.

[0071] Figure 41 This is a schematic side view of an embodiment of an optical concentration measuring device 2100.

[0072] Figure 42 This is a schematic side view of an embodiment of an optical concentration measuring device 2100.

[0073] Figure 43 This is a schematic side view of an embodiment of an optical concentration measuring device 2200.

[0074] Figure 44 This is a schematic side view of an embodiment of an optical concentration measuring device 2300.

[0075] Figure 45 This is a schematic top view of an embodiment of an optical concentration measuring device 2400.

[0076] Figure 46 This is to explain the calculation. Figure 17 The figure shows an example of a method for depicting the full length of an optical waveguide 743 in a curved shape when viewed from above.

[0077] Figure 47 It is a graph showing the relationship between the side length of the square surrounding the optical waveguide 743 and the total length and effective optical path length of the optical waveguide 743 when viewed from above.

[0078] Figure 48 It is a graph showing the relationship between the side length of the occupied area of ​​a square measured by an optical concentration meter 600 with optical waveguide 743 and the effective optical path length of optical waveguide 743.

[0079] Figure 49 It is shown Figure 48 The graph shows the relationship between the volume of the optical concentration meter 600 and the effective optical path length of the optical waveguide 743 in the example.

[0080] Label Explanation

[0081] 100 Optical Concentration Meter

[0082] 110 vocal cavities

[0083] 111 Gas Inlet

[0084] 120 Optical Components

[0085] 130 light source

[0086] 140 Optical Waveguide

[0087] 150 substrates

[0088] 190 Sound Transducer

[0089] 220 Optical Components

[0090] 300 Optical Concentration Meter

[0091] 320 Optical Components

[0092] 360° Optical Coupler

[0093] 321 Optical Components

[0094] 361 Optical Coupler

[0095] 322 Optical Components

[0096] 362 Optical Coupler

[0097] 323 Optical Components

[0098] 363 Optical Coupler

[0099] 400 Optical Concentration Meter

[0100] 420 Optical Components

[0101] 451 base plate

[0102] 452 substrate

[0103] 460 Optical Coupler

[0104] 401 Optical Concentration Meter

[0105] 421 Optical Components

[0106] 453 substrate support

[0107] 402 Optical Concentration Meter

[0108] 422 Optical Components

[0109] 500 Optical Concentration Meter

[0110] 520 Optical Components

[0111] 550 base plate

[0112] 551 Support section

[0113] 600 Optical Concentration Meter

[0114] 620 Optical Components

[0115] 650 base plate

[0116] 651 Support section

[0117] 621 Optical Components

[0118] 622 Optical Components

[0119] 640 Optical Waveguide

[0120] 741 Optical Waveguide

[0121] 742 Optical Waveguide

[0122] 743 Optical Waveguide

[0123] 820 Optical Components

[0124] 840 Optical Waveguide

[0125] 841 Reflection Unit

[0126] 920 Optical Components

[0127] 921 Optical Components

[0128] 940 Optical Waveguide

[0129] 941 Elliptical Encircling Part

[0130] 950 base plate

[0131] 951 Support section

[0132] 1021 Optical Components

[0133] 1130 Light Source

[0134] 1120 Optical Components

[0135] 1140 Optical Waveguide

[0136] 1141 Annular surrounding portion

[0137] 1220 Optical Components

[0138] 1240 Optical Waveguide

[0139] 1241 Annular surrounding part

[0140] 1300 Optical Concentration Meter

[0141] 1320 Optical Components

[0142] 1370 Photodetector

[0143] 1400 Optical Concentration Meter

[0144] 1420 Optical Components

[0145] 1450 base plate

[0146] 1451 Support section

[0147] 1452 base plate

[0148] 1470 Photodetector

[0149] 1520 Optical Components

[0150] 1570 Photodetector

[0151] 1620 Optical Components

[0152] 1670 Photodetector

[0153] 1800 Optical Concentration Meter

[0154] 1820 Optical Components

[0155] 1880 Optical Filter

[0156] 1821 Optical Components

[0157] 1831 Light Source

[0158] 1881 Optical Filter

[0159] 1822 Optical Components

[0160] 1832 Light Source

[0161] 1882 Optical Filter

[0162] 1823 Optical Components

[0163] 1833 Light Source

[0164] 1883 Optical Filter

[0165] 1900 Optical Concentration Meter

[0166] 1920 Optical Components

[0167] 1940 Optical Waveguide

[0168] 1901 Optical Concentration Meter

[0169] 1921 Optical Components

[0170] 1941 Optical Waveguide

[0171] 2000 Optical Concentration Meter

[0172] 2020 Optical Components

[0173] 2030 Light Source

[0174] 2040 optical waveguide

[0175] 2001 Optical Concentration Meter

[0176] 2021 Optical Components

[0177] 2031 Light Source

[0178] 2041 Optical Waveguide

[0179] 2100 Optical Concentration Meter

[0180] 2110 Vocal cavity

[0181] 2112 Base section

[0182] 2113 Surface

[0183] 2114 cover

[0184] 2115 Adhesive

[0185] 2200 Optical Concentration Meter

[0186] 2210 Vocal cavity

[0187] 2212 Base section

[0188] 2213 Surface

[0189] 2216 Conductive Part

[0190] 2217 Inner contact end

[0191] 2218 Outer contact end

[0192] 2300 Optical Concentration Meter

[0193] 2392 Dust Filter

[0194] 2400 Optical Concentration Meter

[0195] 2494 circuit Detailed Implementation

[0196] The following embodiments do not limit the invention as claimed. The combinations of features described in the embodiments are not necessarily all necessary for the solution of the invention.

[0197] Figure 1 This is a schematic side view of an embodiment of an optical concentration measuring device 100. Figure 2 yes Figure 1 A schematic top view of the optical concentration measuring device 100 shown. Figure 1 The diagram shows mutually orthogonal XYZ axes. Figure 1 In the diagram, the X-axis extends horizontally when viewed from the paper, with the right side of the paper being the positive side of the X-axis. The Y-axis extends in the depth direction when viewed from the paper, with the inside of the paper being the positive side of the Y-axis. The Z-axis extends vertically when viewed from the paper, with the top of the paper being the positive side of the Z-axis. Figure 2 The following figures also show the relationship with Figure 1 The XYZ axes correspond to the XYZ axes, and repeated descriptions will be omitted hereafter.

[0198] The optical concentration meter 100 includes a sound cavity 110 for containing gas, an optical component 120 disposed within the sound cavity 110, and a sound transducer 190. Figure 1 Side view and Figure 2 In the top view, it is shown through a portion of the acoustic cavity 110. Figure 3 The same applies to the subsequent side views and top views; repeated descriptions will be omitted hereafter.

[0199] The optical concentration meter 100 is a device used to measure the concentration of a target component in a gas contained within a acoustic cavity 110 using the photoacoustic effect. The photoacoustic effect is a phenomenon in which molecules that absorb light energy release heat and generate sound waves by utilizing the volume expansion caused by this heat. The optical concentration meter 100 can also be referred to as a photoacoustic gas sensor.

[0200] The acoustic cavity 110 has a gas inlet 111 to contain gas introduced through the gas inlet 111. The inner wall of the acoustic cavity 110 may or may not reflect light.

[0201] The optical component 120 has a light source 130, an optical waveguide 140, and a substrate 150. The optical component 120 may also have one or more light sources 130, one or more optical waveguides 140, and one or more substrates 150, each of which is present in this example.

[0202] Light source 130 emits light with wavelengths that are absorbed by the target component in the gas. The wavelength of the light emitted by light source 130 can be set according to the target component whose concentration is measured by optical concentration meter 100. For example, if the target component is carbon dioxide molecules (CO2), the wavelength of the light can be around several μm, that is, the light can be mid-infrared. It should be noted that in Figure 1 In the following figures, the light from light source 130 is schematically represented by straight dashed lines, and repeated explanations will be omitted thereafter.

[0203] Optical waveguide 140 is optically connected to light source 130, and light from light source 130 propagates inside optical waveguide 140. At least a portion of optical waveguide 140 is exposed into the space within acoustic cavity 110. The total length of optical waveguide 140 is, for example, about 2 cm. In the case where optical component 120 has multiple optical waveguides 140, the total length of the multiple optical waveguides 140 can also be about 2 cm. The width of optical waveguide 140 is, for example, about 3 μm. These dimensions can vary depending on the design of optical concentration meter 100, optical waveguide 140, etc.

[0204] The substrate 150 supports the light source 130 and the optical waveguide 140. In this example, the light source 130 and the optical waveguide 140 are both disposed on a substrate 150 and are in direct contact with each other.

[0205] The optical concentration meter 100 enables the acoustic transducer 190 to detect sound waves generated by the absorption of light from the optical component 120 by the target component. Based on the intensity of the electrical signal output from the acoustic transducer 190 that detects the sound wave, the concentration of the target component can be determined. More specifically, the acoustic transducer 190 outputs an electrical signal corresponding to pressure changes within the acoustic cavity 110, which are generated by the absorption of evanescent waves by the target component in a gas surrounding the optical waveguide 140 that has a lower refractive index than the optical waveguide 140. These evanescent waves leak out of the optical waveguide 140 as light from the light source 130 propagates within the optical waveguide 140. It should be noted that... Figure 1 In subsequent diagrams, the evanescent wave will be represented schematically by dots, and the sound wave by straight dashed lines. Repeated explanations will be omitted.

[0206] The optical concentration meter 100 reduces its size compared to a comparative example where the optical path and acoustic cavity 110 are not separated, by separating the light path from the light absorbed by the target component in the gas and the sound generated by the absorption of light by the target component. In other words, it achieves miniaturization. For example, the optical concentration meter 100 has a size of 10 mm. 3 The following volume is described. The optical concentration meter 100 is miniaturized in this way while ensuring that the effective optical path length of the optical waveguide 140 is 10 mm or more. The relationship between the volume of the optical concentration meter 100 and the effective optical path length will be described in detail later.

[0207] Furthermore, by separating the optical path from the acoustic cavity 110, the optical concentration meter 100 offers greater design and manufacturing flexibility compared to the comparative example meter described above. Additionally, the comparative example meter described above could be, for example, the meter disclosed in Patent Document 1.

[0208] It should be noted that, in Figure 1 In the following figures, for simplicity and clarity, the optical component 120 and the acoustic transducer 190 of the optical concentration meter 100 are shown at approximately the same size, but please note that the size ratios of these structures are not limited to those shown in the figures. Furthermore, in the optical concentration meter 100, the optical component 120 may also be without a substrate 150. In this case, the light source 130 and the optical waveguide 140 of the optical component 120 can be directly disposed within the acoustic cavity 110.

[0209] Figure 3 This is a schematic side view of an optical component 220 according to one embodiment. Figure 1 and Figure 2The optical concentration meter 100 of one embodiment shown can also replace the optical component 120 with an optical component 220 in which a light source 130 is formed on the positive Z-axis side of the optical waveguide 140. In the optical component 220, similarly to the optical component 120, both the light source 130 and the optical waveguide 140 are disposed on a substrate 150 and are in direct contact with each other. By having optical components 120 and 220 configured in this way, the optical concentration meter 100 can efficiently propagate light from the light source 130 to the optical waveguide 140, and can also miniaturize the optical components 120 and 220.

[0210] In addition, regarding the use Figure 3 The various embodiments illustrated in the following figures are for illustrative and practical purposes only. Figure 1 and Figure 2 The differences are illustrated in one embodiment. In subsequent embodiments, the differences will be... Figure 1 and Figure 2 In one embodiment, the structural reference numerals corresponding to the structures are the same, and repeated descriptions are omitted.

[0211] Figure 4 This is a schematic side view of an optical concentration meter 300 according to one embodiment. The optical concentration meter 300 differs from the optical concentration meter 100 in that it includes an optical component 320 with an optical coupler 360 instead of the optical component 120. In the optical component 320, the light source 130 and the optical waveguide 140 are both disposed on a substrate 150 and optically coupled to each other via the optical coupler 360. By including the optical component 320 configured in this way, the optical concentration meter 300 allows for independent design of the light source 130, the optical coupler 360, and the optical waveguide 140, thereby increasing design flexibility. Furthermore, by including the optical component 320 configured in this way, the optical concentration meter 300 can be miniaturized.

[0212] Figure 5 This is a schematic side view of the optical component 321 in one embodiment. The optical concentration meter 300 may also include... Figure 5 The optical component 320 is replaced by an optical component 321, which is a grating surrounded by a dashed frame and has an optical coupler 361 composed of a diffraction grating.

[0213] Figure 6 This is a schematic side view of the optical component 322 in one embodiment. The optical concentration meter 300 may also include... Figure 6 Optical component 320 is replaced by optical component 322, which is surrounded by a dashed frame and has an optical coupler 362 consisting of two sets of gratings sandwiched in an intermediate cladding.

[0214] Figure 7This is a schematic side view of the optical component 323 according to one embodiment. The optical concentration meter 300 may also include... Figure 7 The optical component 320 is replaced by an optical component 323, which is surrounded by a dashed frame and has an optical coupler 363 consisting of an optical coupler with an intermediate cladding.

[0215] Figure 8 This is a schematic side view of an optical concentration meter 400 according to one embodiment. The optical concentration meter 400 differs from the optical concentration meter 100 in that it includes an optical component 420 instead of the optical component 120, which has two substrates 451 and 452 and an optical coupler 460. In the optical component 420, the light source 130 and the optical waveguide 140 are respectively disposed on different substrates 451 and 452 and are optically coupled to each other via the optical coupler 460. By including the optical component 420 configured in this way, the optical concentration meter 400 can be designed with only the light source 130, unlike other components such as the optical coupler 460 and the optical waveguide 140, thereby increasing design flexibility.

[0216] Figure 9 This is a schematic side view of an optical concentration meter 401 according to one embodiment. The optical concentration meter 401 differs from the optical concentration meter 400 in that it includes an optical component 421 instead of an optical component 420. In the optical component 420, light from the light source 130 is emitted from the side of the light source 130 on the positive X-axis side, but in the optical component 421, light from the light source 130 is emitted from the surface of the substrate 451 on the negative Z-axis side. The optical component 421 includes a substrate support 453 that holds the substrate 451 in a predetermined position.

[0217] Figure 10 This is a schematic side view of an optical concentration meter 402 according to one embodiment. The optical concentration meter 402 differs from the optical concentration meter 401 in that it has an optical component 422 instead of an optical component 421. In the optical component 421, light from the light source 130 is emitted from the negative Z-axis side of the substrate 451, but in the optical component 422, light from the light source 130 is emitted from the negative Z-axis side of the light source 130.

[0218] Figure 11This is a schematic side view of an optical concentration meter 500 according to one embodiment. The optical concentration meter 500 differs from the optical concentration meter 100 in that it includes an optical component 520 instead of the optical component 120, which separates at least a portion of the optical waveguide 140 from the substrate 550 via a support portion 551. In the optical component 520, at least a portion of the optical waveguide 140 in the direction of light propagation within the optical waveguide 140 is not in contact with the substrate 550, and its entire surface is exposed into the space within the acoustic cavity 110. The optical component 520 can also be defined as having at least a portion of the optical waveguide 140 suspended.

[0219] The optical concentration meter 500, by including the optical component 520 configured in this way, can prevent light leakage and absorption from the optical waveguide 140 to the substrate 550, thereby improving the light propagation efficiency in the optical waveguide 140. To achieve this effect, the separation distance between the optical waveguide 140 and the substrate 550 can be greater than the leakage length of the evanescent wave that leaks out of the optical waveguide 140 during the propagation of light from the light source 130 within the optical waveguide 140, for example, it can be 2 μm or more. In addition, the optical concentration meter 500 with the optical component 520 can increase the contact between the evanescent wave and the target component contained in the gas present around the optical waveguide 140 and having a refractive index lower than that of the optical waveguide 140, which leaks out of the optical waveguide 140 during the propagation of light from the light source 130 within the optical waveguide 140. Therefore, the optical concentration meter 500 can increase the pressure fluctuation amplitude in the acoustic cavity 110 by enabling more object components to absorb evanescent waves, thereby increasing the output of the sound transducer 190.

[0220] Figure 12 This is a schematic side view of an optical concentration meter 600 according to one embodiment. The optical concentration meter 600 differs from the optical concentration meter 500 in that it includes an optical component 620 instead of the optical component 520, which separates at least a portion of the light source 130 and the optical waveguide 140 from the substrate 650 via a support portion 651 of the substrate 650. In the optical component 620, a space is provided between the light source 130 and the substrate 650. In the optical component 620, at least a portion of the light source 130 and the optical waveguide 140 can be defined as being suspended.

[0221] The optical concentration meter 600, by including an optical component 620 configured in this way, can prevent light leakage and light absorption from the light source 130 and the optical waveguide 140 to the substrate 650. Therefore, it can enable the light from the light source 130 to propagate efficiently to the optical waveguide 140 and improve the light propagation efficiency in the optical waveguide 140. To achieve this effect, the separation distance between the light source 130 and the substrate 650 can be greater than the leakage length of the evanescent wave from the light source 130 into the space between the light source 130 and the substrate 650, for example, it can be 2 μm or more.

[0222] Figure 13 This is a schematic side view of an optical component 621 according to one embodiment. The optical concentration meter 600 may also have an optical component 621 with a light source 130 formed on the positive Z-axis side of the optical waveguide 140 instead of the optical component 620.

[0223] Figure 14 This is a schematic side view of an optical component 622 according to one embodiment. The optical concentration meter 600 may also replace the optical component 320 with an optical component 622 on the positive Z-axis side of the optical waveguide 640, where the light source 130 is formed and the film thickness of the optical waveguide 640 located on the positive Z-axis side closest to the light source 130 is relatively thinner. For example... Figure 14 As shown, the optical waveguide 640 can be stepped in such a way that the film thickness is thinner only at that location, or the film thickness can be gradually increased or smoothly increased from that location toward the positive X-axis. The optical concentration meter 600, by having an optical component 622 with an optical waveguide 640 having a thinner film thickness at that location, can suppress light leakage to the substrate 650 via the support portion 651.

[0224] It should be noted that, in several subsequent embodiments, as an example, [the following is an example of...]. Figure 12 Similarly, the example is described with a space provided between the light source 130 and the substrate 650, and at least a portion of the optical waveguide 140 is supported on the support portion 651 of the substrate 650 in such a way that it does not contact the substrate 650 and the entire surface is exposed.

[0225] Figure 15 This is a schematic top view of an embodiment of the optical waveguide 741. Figures 1 to 14 For clarity, the shape of the optical waveguide 140, etc., as shown in top view is simplified. Optical components such as the optical concentration meter 100, etc., may also have an optical waveguide 741 instead of the optical waveguide 140. The optical waveguide 741 has a tortuous shape when viewed from above.

[0226] Figure 16This is a schematic top view of an embodiment of the optical waveguide 742. Optical components such as the optical concentration meter 100 and the like may also have the optical waveguide 742 instead of the optical waveguide 140. In top view, the optical waveguide 742 is a shape formed by alternating straight lines and curves.

[0227] Figure 17 This is a schematic top view of an embodiment of the optical waveguide 743. Optical components such as the optical concentration meter 100 and the like may also have the optical waveguide 743 instead of the optical waveguide 140. The optical waveguide 743 has a shape formed by a curved path when viewed from above.

[0228] Figures 15 to 17 The optical waveguides 741, 742, and 743 shown can be defined as including, at least partially, a curved portion that bends the propagation direction of light propagating within the optical waveguide 741. Furthermore, the optical waveguide 741, etc., can also be defined as having at least a portion that is not straight when viewed from above. The optical concentration meter 100, etc., by incorporating optical components 120, etc., including the optical waveguide 741, etc., can extend the optical path length per unit area on the surface of the substrate 150, etc.

[0229] Figure 18 This is a schematic side view of the optical waveguide 840 and the light source 130 of an optical component 820 according to one embodiment. Figure 18 For the purpose of clarifying the invention, illustrations of other components included in the optical component 820 have been omitted. In subsequent figures, illustrations of some components will also be omitted for the same purpose, and repeated descriptions will be omitted thereafter.

[0230] Optical concentration measuring devices such as 100 may also include optical components 820 instead of optical components 120. In the optical component 820, the optical waveguide 840 at least partially includes one or more pairs of reflective elements 841, which restore the propagation direction of light propagating within the optical waveguide 840 after reversal. The reflective elements 841 can be, for example, gratings, metals, or reflections between high-refractive-index and low-refractive-index materials. The optical waveguide 840 can be defined as having at least a portion of a section sandwiched between mirrors. By including the optical component 820, optical concentration measuring devices such as 100 can extend the optical path length per unit area on the surface of the substrate 150, etc.

[0231] Figure 19 This is a schematic top view of an optical component 920 according to one embodiment. Optical concentration measuring devices such as the 100 may also include the optical component 920 instead of the optical component 120. In the optical component 920, the optical waveguide 940 partially includes an elliptical surrounding portion 941 that causes light propagating within the optical waveguide 940 to circumferentially surround an ellipse. The straight portion of the optical waveguide 940 other than the elliptical surrounding portion 941 is referred to as a straight waveguide.

[0232] Optical concentration measuring devices such as 100, by including optical components 920, can extend the optical path length per unit area on the surface of substrates such as 150. Furthermore, optical concentration measuring devices such as 100... Figure 19 As in one embodiment, when a linear waveguide is connected to input light into the elliptical surrounding portion 941, the mode of the input light can be controlled by the waveguide width, enabling the light to efficiently surround the elliptical surrounding portion 941. Furthermore, when the linear waveguide for inputting light into the elliptical surrounding portion 941 is connected at an angle along the tangent of the ellipse, the optical concentration meter 100 and the like can also enable the light to efficiently surround the elliptical surrounding portion 941.

[0233] Figure 20 This is a schematic top view of an optical component 921 according to one embodiment. Figure 21 yes Figure 20 A schematic side view of the optical component 921 shown. Figure 20 In the diagram, the support portion 951 of the substrate 950 of the optical component 921 is indicated by a dashed line. The optical concentration measuring instrument 100 and the like may also include the optical component 921 instead of the optical component 920.

[0234] In the optical component 921, the optical waveguide 940 generally includes an elliptical surrounding portion 941 that causes light propagating within the optical waveguide 940 to circumferentially surround an ellipse; that is, the optical waveguide 940 is an elliptical waveguide. The light source 130 is positioned at a location that overlaps with the elliptical surrounding portion 941 when viewed from above. Optical concentration measuring devices 100, etc. Figure 20 and 21 As in one embodiment, when the light source 130 is provided within the elliptical surrounding portion 941, the light emitted from the light source 130 can be input into the elliptical surrounding portion 941 more efficiently. Furthermore, in this case, as... Figure 20 As shown, the optical concentration measuring device 100 and the like can make light efficiently surround the elliptical surrounding portion 941 by setting the light source 130 outside the elliptical focal point of the elliptical surrounding portion 941.

[0235] Furthermore, in the optical component 921, when viewed from above, the support portion 951 of the substrate 950 supports the inner side of the elliptical focal point of the elliptical surrounding portion 941, so that the outer side of the elliptical focal point of the elliptical surrounding portion 941 does not contact the substrate 950 and its entire surface is exposed to the space inside the acoustic cavity 110. As a result, the optical concentration meter 100 and the like can improve the propagation efficiency of light surrounding the outer side of the elliptical focal point of the elliptical surrounding portion 941, and can increase the contact between the evanescent wave and the target component contained in the gas present around the optical waveguide 940 and having a refractive index lower than the optical waveguide 940, which leaks out to the outside of the optical waveguide 940 as light from the light source 130 propagates within the optical waveguide 940. Additionally, by supporting at least a portion of the area inside the elliptical focal point of the elliptical surrounding portion 941 with the support portion 951 of the substrate 950, the optical concentration meter 100 and the like can stabilize the support of the optical waveguide 940.

[0236] Figure 22 This is a schematic top view of an optical component 1021 according to one embodiment. Figure 22 In the diagram, the support portion 951 of the substrate 950 of the optical component 1021 is indicated by a dashed line. Optical concentration measuring instruments such as the optical component 100 may also use the optical component 1021 instead of the optical component 921, which has a light source 1130 configured such that a portion of its shape roughly follows the outline of the elliptical surrounding portion 941. Optical concentration measuring instruments such as the optical component 100... Figure 22 As in one embodiment, by placing the light source 1130 outside the elliptical focal point of the elliptical surround portion 941 and increasing the surface area of ​​the light source 1130, the amount of light input to the elliptical surround portion 941 can be increased.

[0237] Figure 23 This is a schematic top view of the optical waveguide 1140 and the light source 130 of an embodiment of the optical component 1120. Optical concentration measuring devices such as the 100 may also use the optical component 1120 instead of the optical component 120. In the optical component 1120, the optical waveguide 1140 at least partially includes an annular surrounding portion 1141 that causes light propagating within the optical waveguide 1140 to circumferentially orbit an ellipse or a circle. The straight portion of the optical waveguide 1140 other than the annular surrounding portion 1141 is referred to as a straight waveguide. In the optical waveguide 1140, the connection between the annular surrounding portion 1141 and the straight waveguide constitutes a directional coupler, and the separation distance between the annular surrounding portion 1141 and the straight waveguide at this connection portion can be adjusted.

[0238] Optical concentration measuring instruments such as the 100, by including optical components 1120, can extend the optical path length per unit area on the surface of the substrate 150, etc. Furthermore, such as Figure 23As shown in one embodiment, the optical concentration meter 100 and the like can efficiently guide light into the annular surrounding portion 1141 by controlling the distance between the linear waveguide and the annular surrounding portion 1141.

[0239] Figure 24 This is a schematic top view of the optical waveguide 1240 and the light source 130 of the optical component 1220 according to one embodiment. The optical concentration meter 100 and the like may also include the optical component 1220 instead of the optical component 1120. In the optical component 1220, there is no gap between the annular surrounding portion 1241 and the linear waveguide; that is, they are integrally formed. By including the optical component 1220, the optical concentration meter 100 and the like can eliminate the necessity of micro-machining of dimensions smaller than the waveguide width, and can be easily manufactured.

[0240] Figure 25 This is a schematic top view of an embodiment of an optical concentration measuring device 1300. Figure 26 yes Figure 25 The schematic side view of the optical concentration meter 1300 is shown. The optical concentration meter 1300 differs from the optical concentration meter 100 in that it has an additional optical component 1320 with a light receiver 1370 instead of the optical component 120.

[0241] The photodetector 1370 detects light from the light source 130. In this example, the photodetector 1370 is disposed in direct contact with the opposite end of the two ends of the optical waveguide 140 that are in direct contact with the light source 130. Furthermore, the light source 130 can adjust the output of emitted light based on the detection result of the photodetector 1370. The optical concentration meter 1300, by providing such an optical component 1320, can detect the light output of the light source 130 and perform signal processing corresponding to that light output, such as adjusting the light output of the light source 130. In this example, the photodetector 1370 and other components, including the light source 130, are disposed together on a substrate 650. Therefore, the optical concentration meter 1300 can be miniaturized.

[0242] Figure 27 This is a schematic top view of an embodiment of an optical concentration measuring device 1400. Figure 28 yes Figure 27 The diagram shows a schematic side view of the optical concentration meter 1400. The optical concentration meter 1400 differs from the optical concentration meter 1300 in that it includes an optical component 1420 instead of the optical component 1320. In the optical component 1420, a light receiver 1470 is disposed on a substrate 1452, which is different from the substrate 1450 on which other components such as the light source 130 are disposed. Furthermore, the light receiver 1470 is disposed next to the light source 130 to detect light from... Figure 28The light leakage of the light source 130 located on the support portion 1451 of the substrate 1450 is shown by the dashed line. By providing such an optical component 1420, the optical concentration meter 1400 can be designed with only the light receiver 1470, which is different from other components such as the light source 130.

[0243] Figure 29 This is a schematic top view of an optical component 1520 according to one embodiment. Figure 30 This is a schematic top view of the optical component 1620 according to one embodiment. The optical concentration meter 1300 may also include optical components 1520 and 1620 with light receivers 1570 and 1670 disposed next to the light source 130, instead of optical component 1320. Figure 29 In the example of optical component 1520, the light receiver 1570 is connected to the light source 130 via a waveguide. On the other hand, in Figure 30 In the example of optical component 1620, the light receiver 1670 is not connected to the light source 130.

[0244] Figure 31 yes Figure 30 A schematic side view of the optical component 1620 is shown. A light receiver 1670 is disposed on a substrate 650 next to the light source 130 to detect light from... Figure 31 The light leakage of the light source 130 located on the support portion 651 of the substrate 650 is shown by the dashed line. (Example:) Figure 31 As shown, the light leakage detected by the light receiver 1670 may include direct light arriving directly from the light source 130 to the light receiver 1670, or reflected light arriving from the surface or back of the substrate 650. The optical concentration meter 1300, by providing such an optical component 1620, can detect the light output of the light source 130 without reducing the amount of light from the light source 130 used to determine the concentration of the target component in the gas.

[0245] Figure 32 This is a schematic top view of an optical concentration meter 1800 according to one embodiment. The optical concentration meter 1800 differs from the optical concentration meter 100 in that it has an optical component 1820 instead of an optical component 120, which additionally has an optical filter 1880 disposed between the light source 130 and the optical waveguide 140.

[0246] The optical filter 1880 directs light from the light source 130 to the wavelengths absorbed by the target component in the gas and blocks light of other wavelengths. By providing such an optical component 1820, the optical concentration meter 1800 can prevent components other than the target component in the gas from absorbing light from the light source 130 and generating sound waves, thereby improving the accuracy of the concentration measurement of the target component.

[0247] Figure 33 This is a schematic top view of the optical filter 1881, light source 1831, and optical waveguide 140 of an embodiment of the optical component 1821. The optical concentration meter 1800 may also include an optical component 1821 instead of the optical component 1820, which has a structure formed by... Figure 33 An optical filter 1881, consisting of a grating surrounded by a dashed frame, and a light source 1831 optically connected to the optical filter 1881.

[0248] Figure 34 This is a schematic top view of the optical filter 1882, light source 1832, and optical waveguide 140 of an embodiment of the optical component 1822. The optical concentration meter 1800 may also include an optical component 1822 instead of the optical component 1820, which has a structure formed by... Figure 34 An optical filter 1882 consisting of a side grating surrounded by a dashed frame and a light source 1832 optically connected to the optical filter 1882.

[0249] Figure 35 This is a schematic top view of the optical filter 1883, light source 1833, and optical waveguide 140 of an embodiment of the optical component 1823. The optical concentration meter 1800 may also include an optical component 1823 instead of the optical component 1820, which has a structure formed by... Figure 35 An optical filter 1883 consisting of a focusing grating surrounded by a dashed frame and a light source 1833 optically connected to the optical filter 1883.

[0250] In addition, Figures 33 to 35 In the various optical components 1821 shown, wavelengths not selected by the grating may be emitted into the acoustic cavity 110. However, by designing the reflected light path length within the acoustic cavity 110 to be sufficiently short compared to the light path length of the optical waveguide 140, it is possible to suppress the absorption of light emitted into the acoustic cavity 110 by components in the gas other than the target component, thereby generating sound waves. This improves the accuracy of the concentration measurement of the target component. For this purpose, using... Figure 40 To be described later.

[0251] Figure 36 This is a schematic top view of an optical concentration meter 1900 according to one embodiment. The optical concentration meter 1900 differs from the optical concentration meter 100 in that it includes an optical component 1920 instead of an optical component 120. This optical component 1920 has multiple optical waveguides 1940 optically connected to a light source 130 on a substrate 650. As described above, the total length of the multiple optical waveguides 1940 is, for example, about 2 cm.

[0252] When light travels a long distance in a waveguide, it attenuates due to propagation loss. However, according to the optical concentration meter 1900, by having an optical component 1920 that connects each of the shorter optical waveguides 1940 to multiple light sources 130, it is possible to reduce such propagation loss while ensuring the total optical path length.

[0253] Figure 37 This is a schematic top view of an embodiment of an optical concentration meter 1901. The optical concentration meter 1901 differs from the optical concentration meter 1900 in that it includes an optical component 1921 instead of an optical component 1920. This optical component 1921 is arranged in such a manner that multiple optical waveguides 1941, optically connected to a light source 130, extend radially from the light source 130. By including such an optical component 1921, the optical concentration measuring instrument 1901 can reduce propagation loss while ensuring the total optical path length.

[0254] Figure 38 This is a schematic top view of an optical concentration meter 2000 according to one embodiment. The optical concentration meter 2000 differs from the optical concentration meter 100 in that it has an optical component 2020 instead of an optical component 120, which has multiple light sources 2030 optically connected to multiple optical waveguides 2040 on a substrate 650.

[0255] Figure 39 This is a schematic top view of an optical concentration meter 2001 according to one embodiment. The optical concentration meter 2001 differs from the optical concentration meter 2000 in that it has an optical component 2021 instead of an optical component 2020. The optical component 2021 has a plurality of light sources 2031 that are optically connected to an optical waveguide 2041 on a substrate 650.

[0256] Using multiple light sources increases luminous intensity, strengthens the photoacoustic signal, and improves gas sensitivity. However, the drawback is high power consumption for driving the light sources. Conversely, using fewer light sources reduces luminous intensity, weakens the photoacoustic signal, and decreases gas sensitivity. The advantage, however, is low power consumption for driving the light sources. Figure 38 and Figure 39 The optical concentration measuring devices 2000 and 2001 shown can adjust the light intensity and power consumption by selectively driving one or more of the multiple light sources 2030 and 2031 by setting the aforementioned optical components 2020 and 2021.

[0257] Figure 40 yes Figure 6 A schematic side view of the optical concentration meter 600 shown. Figure 40 In, with Figure 6The difference is indicated by dashed lines representing light leakage from the light source 130. In optical concentration measuring instruments such as the 600, the average optical path length of the light from the light source 130 that does not enter the optical waveguide 140 but is radiated into the space within the acoustic cavity 110 and reflected by the inner wall of the acoustic cavity 110 can also be shorter than the effective optical path length of the optical waveguide 140. By designing the optical concentration measuring instrument 600 in this way, it is possible to suppress the absorption of light leakage radiated into the space within the acoustic cavity 110 by components other than the target component in the gas, which generates sound waves due to reflection by the inner wall, thereby improving the accuracy of the concentration measurement of the target component.

[0258] To shorten the average optical path length of the leaked light compared to the optical path length of the optical waveguide 140, the average reflectivity of the inner wall of the acoustic cavity 110 can be made to be 70% or less, for example. Specifically, assuming the average reflectivity of the inner wall of the acoustic cavity 110 is R, when the leaked light is reflected N times at the inner wall, the intensity of the leaked light becomes R×N. The number of reflections at the inner wall required to reduce the intensity of the leaked light to, for example, less than one-tenth is 22 times when R=0.9, 11 times when R=0.8, 7 times when R=0.7, 5 times when R=0.6, and 4 times when R=0.5. Therefore, in the optical concentration meter 600, by making the average reflectivity of the inner wall less than 70%, the average optical path length of the leaked light can be reduced to less than one-third compared to the case with an average reflectivity of 90%. Thus, it can be seen that when the average reflectivity of the inner wall is less than 70%, the effect of reducing the optical path length of the leaked light relative to the reduction in reflectivity is significant.

[0259] Figure 41 This is a schematic side view of an optical concentration meter 2100 according to one embodiment. The optical concentration meter 2000 differs from the optical concentration meter 600 in that it has a sound cavity 2110 instead of a sound cavity 110, which has a base portion 2112 and a cover portion 2114 that are separate from each other.

[0260] In the acoustic cavity 2110, the base portion 2112 is the part where the optical component 120 and the sound transducer 190 are disposed on the surface 2113, and the cover portion 2114 is the part where the gas inlet 111 is formed and is mounted on the base portion 2112. The optical concentration measuring instrument 2100, by having such an acoustic cavity 2110, can be easily manufactured by disposing of components such as the optical component 120 and the sound transducer 190, which are pre-determined to be disposed in the acoustic cavity 2110, on the surface 2113 of the base portion 2112, and then mounting the cover portion 2114 on the base portion 2112.

[0261] Figure 42 This is a schematic side view of an embodiment of an optical concentration measuring device 2100. Figure 42 The optical concentration measuring device 2100 shown is... Figure 41The difference in the optical concentration meter 2100 shown is that the cover 2114 is bonded to the base 2112 by adhesive 2115. Therefore, the internal space of the acoustic cavity 2110 is only connected to the external space of the acoustic cavity 2110 via the gas inlet 111. According to... Figure 42 Compared to the case where the cover 2114 is non-adhesively placed on the base 2112, the optical concentration measuring device 2100 shown has improved sealing between the cover 2114 and the base 2112, and improved airtightness of the internal space of the acoustic cavity 2110. As a result, it is possible to prevent the attenuation of pressure fluctuations within the acoustic cavity 2110.

[0262] Figure 43 This is a schematic side view of an embodiment of an optical concentration meter 2200. The optical concentration meter 2200 and... Figure 41 The optical concentration meter 2100 shown differs in that the base 2212 has a conductive portion 2216. The conductive portion 2216 includes an inner contact end 2217 formed on the surface 2213 of the base 2212 and an outer contact end 2218 exposed to the external space of the acoustic cavity 2210. The inner contact end 2217 is electrically connected to at least one of the light source 130 and the sound transducer 190. According to the optical concentration meter 2200, by having such an acoustic cavity 2210, conduction between the inner and outer sides of the acoustic cavity 2210 can be achieved.

[0263] Figure 44 This is a schematic side view of an embodiment of an optical concentration meter 2300. The optical concentration meter 2300 differs from the optical concentration meter 600 in that it additionally includes a dust filter 2392. The dust filter 2392 is installed at the gas inlet 111 of the acoustic cavity 110, sealing the gas contained within the acoustic cavity 110. By including such a dust filter 2392, the optical concentration meter 2300 can prevent foreign objects from entering the acoustic cavity 110.

[0264] Figure 45 This is a schematic top view of an optical concentration meter 2400 according to one embodiment. The optical concentration meter 2400 differs from the optical concentration meter 100 in that it additionally includes a circuit 2494 disposed within the acoustic cavity 110. The circuit 2494 is electrically connected to at least one of the light source 130 and the sound transducer 190.

[0265] Circuit 2494 can function as a light source driving circuit, for example, or it can adjust the output of light emitted from light source 130. Alternatively, circuit 2494 can function as a concentration calculation circuit, or it can calculate the concentration of the target component in the gas based on the output of sound transducer 190. Furthermore, circuit 2494 can also be additionally or alternatively used as an analog-to-digital conversion circuit, a digital data transmission circuit, etc.

[0266] In a sound cavity that utilizes internal reflection, as in the comparative example described above, it is difficult to control the reflectivity of light on the circuit surface if the circuit is placed inside the sound cavity; therefore, the circuit is placed outside the sound cavity. In contrast, according to the optical concentration meter 2400, by separating the optical path from the sound cavity 110, the circuit 2494 can be placed inside the sound cavity 110. Therefore, the optical concentration meter 2400 can be miniaturized, and it can be easily assembled into other devices.

[0267] Figure 46 This is to explain the calculation. Figure 17 This diagram illustrates an example of a method for representing the overall length of an optical waveguide 743, which, when viewed from above, exhibits a shape formed by a curved loop. The overall length L of the optical waveguide 743 is shown. prop It can be calculated using the following [Equation 1]. ΔR is the waveguide width W. waveguide Waveguide spacing W spacing The sum of Rmin and n is the minimum radius of curvature. Additionally, the side length of the square surrounding the optical waveguide 743, i.e., the occupied area length Lfp, when viewed from above, is obtained by adding ΔR to twice the maximum radius of curvature Rmax.

[0268] [Formula 1]

[0269] Figure 47 This is a graph showing the relationship between the side length of the square surrounding the optical waveguide 743, the total length of the optical waveguide 743, and the effective optical path length when viewed from above. The horizontal axis of the graph represents the occupied area length [mm], and the vertical axis represents the optical path length of the optical waveguide 743, i.e., the total length [mm] and the effective optical path length [mm]. Figure 47 In the middle, the curve shown by the dashed line on the upper side represents the total length L of the optical waveguide 743. prop The curve shown on the lower side represents the leakage efficiency η of the optical waveguide 743 multiplied by the total length L. prop And the obtained ηL prop This refers to the effective optical path length. In this example, η is 20%.

[0270] Figure 48This is a graph showing the relationship between the side length of the occupied area of ​​a square measured by an optical concentration meter 600 equipped with an optical waveguide 743 and the effective optical path length of the optical waveguide 743. The horizontal axis of the graph represents the occupied area length Lfp [mm], and the vertical axis represents the effective optical path length Leff [mm]. Figure 48 In the diagram, dots represent the size range of the optical path of the measuring device in the comparative example described above. For example... Figure 48 As shown, in order to ensure an effective optical path length of 10 mm to 50 mm, the measuring device in the comparative example requires an occupation area length of 10 mm to 20 mm Lfp. In contrast, in the optical concentration measuring device 600 with optical waveguide 743, only an occupation area length of less than 5 mm Lfp is required.

[0271] Figure 49 It is shown Figure 48 The graph shows the relationship between the volume of the optical concentration meter 600 and the effective optical path length of the optical waveguide 743 in the example. The horizontal axis of the graph represents the volume Vcell of the optical concentration meter 600, etc. [mm]. 3 The vertical axis of the graph refers to the effective optical path length Leff [mm]. Figure 49 The curve shown represents the cell volume Vcell of an optical concentration meter 600 equipped with an optical waveguide 743. Figure 49 In the diagram, dots represent the size range of the measuring instruments for the comparative examples.

[0272] In an optical concentration meter 600 equipped with an optical waveguide 743, as an example, the height of the acoustic cavity 110, i.e., the unit height of the optical concentration meter 600, is assumed to be 0.5 mm. In this case, such as Figure 49 As shown, in order to ensure an effective optical path length (Leff) of 10 mm to 50 mm, a length of 700 mm is required in the measuring device of the comparative example described above. 3 ~8000mm 3 The unit volume Vcell, in contrast, only needs to be less than 10 mm in optical concentration measuring instruments such as the 600 equipped with an optical waveguide 743. 3 The unit volume Vcell. As described above, the optical concentration measuring device 600 and the like can be significantly miniaturized compared to the measuring device of the comparative example.

[0273] The embodiments described above are for illustrative purposes only; however, the scope of the present invention is not limited to those described in the above embodiments. It will be apparent to those skilled in the art that various modifications or alterations can be made to the above embodiments. As can be seen from the claims, such modifications or alterations are also included within the scope of the present invention.

[0274] It should be noted that the execution order of actions, processes, steps, and stages in the apparatus, system, program, and method shown in the claims, specification, and drawings can be implemented in any order, unless specifically stated as "before" or "prior to," and the output of an earlier process is not used in a later process. Even if terms such as "firstly" or "next" are used for convenience in describing the flow of actions in the claims, specification, and drawings, this does not mean that they must be implemented in that order.

Claims

1. An optical concentration meter for measuring the concentration of a target component in a gas, wherein, The optical concentration measuring device includes: A acoustic cavity having a gas inlet for containing gas introduced through the gas inlet; Optical components are disposed within the acoustic cavity; and A sound transducer is disposed within the acoustic cavity. The optical component has one or more light sources and one or more optical waveguides. The light sources emit light containing wavelengths absorbed by the object component. The optical waveguides are optically connected to the light sources, and the light from the light sources propagates inside the optical waveguides. At least a portion of the optical waveguides is exposed into the space within the acoustic cavity. The sound transducer outputs an electrical signal corresponding to the pressure change within the acoustic cavity. The pressure change within the acoustic cavity is generated by the absorption of evanescent waves by the target component contained in the gas present around the optical waveguide and having a refractive index smaller than that of the optical waveguide. The evanescent waves leak out to the outside of the optical waveguide as the light from the light source propagates within the optical waveguide.

2. An optical concentration measuring instrument for measuring the concentration of a target component in a gas, wherein, The optical concentration measuring device includes: A acoustic cavity having a gas inlet for containing gas introduced through the gas inlet; Optical components are disposed within the acoustic cavity; and A sound transducer is disposed within the acoustic cavity. The optical component has one or more light sources and one or more optical waveguides. The light sources emit light containing wavelengths absorbed by the object component. The optical waveguides are optically connected to the light sources, and the light from the light sources propagates inside the optical waveguides. At least a portion of the optical waveguides is exposed into the space within the acoustic cavity. The optical component has one or more substrates, the substrates supporting the light source and the optical waveguide. The light source and the optical waveguide are both disposed on the substrate and are optically coupled to each other via an optical coupler.

3. An optical concentration measuring instrument for measuring the concentration of a target component in a gas, wherein, The optical concentration measuring device includes: A acoustic cavity having a gas inlet for containing gas introduced through the gas inlet; Optical components are disposed within the acoustic cavity; and A sound transducer is disposed within the acoustic cavity. The optical component has one or more light sources and one or more optical waveguides. The light sources emit light containing wavelengths absorbed by the object component. The optical waveguides are optically connected to the light sources, and the light from the light sources propagates inside the optical waveguides. At least a portion of the optical waveguides is exposed into the space within the acoustic cavity. The optical component has one or more substrates, the substrates supporting the light source and the optical waveguide. The light source and the optical waveguide are respectively disposed on different substrates and are optically coupled to each other via optical couplers.

4. An optical concentration measuring instrument for measuring the concentration of a target component in a gas, wherein, The optical concentration measuring device includes: A acoustic cavity having a gas inlet for containing gas introduced through the gas inlet; Optical components are disposed within the acoustic cavity; and A sound transducer is disposed within the acoustic cavity. The optical component has one or more light sources and one or more optical waveguides. The light sources emit light containing wavelengths absorbed by the object component. The optical waveguides are optically connected to the light sources, and the light from the light sources propagates inside the optical waveguides. At least a portion of the optical waveguides is exposed into the space within the acoustic cavity. The optical component has one or more substrates, the substrates supporting the light source and the optical waveguide. A space is provided between the light source and the substrate.

5. An optical concentration measuring instrument for measuring the concentration of a target component in a gas, wherein, The optical concentration measuring device includes: A acoustic cavity having a gas inlet for containing gas introduced through the gas inlet; Optical components are disposed within the acoustic cavity; and A sound transducer is disposed within the acoustic cavity. The optical component has one or more light sources and one or more optical waveguides. The light sources emit light containing wavelengths absorbed by the object component. The optical waveguides are optically connected to the light sources, and the light from the light sources propagates inside the optical waveguides. At least a portion of the optical waveguides is exposed into the space within the acoustic cavity. The optical waveguide includes at least a partial bend that bends the propagation direction of the light propagating within the optical waveguide.

6. An optical concentration measuring instrument for measuring the concentration of a target component in a gas, wherein, The optical concentration measuring device includes: A acoustic cavity having a gas inlet for containing gas introduced through the gas inlet; Optical components are disposed within the acoustic cavity; and A sound transducer is disposed within the acoustic cavity. The optical component has one or more light sources and one or more optical waveguides. The light sources emit light containing wavelengths absorbed by the object component. The optical waveguides are optically connected to the light sources, and the light from the light sources propagates inside the optical waveguides. At least a portion of the optical waveguides is exposed into the space within the acoustic cavity. The optical waveguide includes at least one or more pairs of reflective elements, which restore the propagation direction of the light propagating within the optical waveguide after reversal.

7. An optical concentration measuring instrument for measuring the concentration of a target component in a gas, wherein, The optical concentration measuring device includes: A acoustic cavity having a gas inlet for containing gas introduced through the gas inlet; Optical components are disposed within the acoustic cavity; and A sound transducer is disposed within the acoustic cavity. The optical component has one or more light sources and one or more optical waveguides. The light sources emit light containing wavelengths absorbed by the object component. The optical waveguides are optically connected to the light sources, and the light from the light sources propagates inside the optical waveguides. At least a portion of the optical waveguides is exposed into the space within the acoustic cavity. The optical waveguide at least partially includes an elliptical surrounding portion, which causes the light propagating within the optical waveguide to surround an ellipse.

8. An optical concentration measuring instrument for measuring the concentration of a target component in a gas, wherein, The optical concentration measuring device includes: A acoustic cavity having a gas inlet for containing gas introduced through the gas inlet; Optical components are disposed within the acoustic cavity; and A sound transducer is disposed within the acoustic cavity. The optical component has one or more light sources and one or more optical waveguides. The light sources emit light containing wavelengths absorbed by the object component. The optical waveguides are optically connected to the light sources, and the light from the light sources propagates inside the optical waveguides. At least a portion of the optical waveguides is exposed into the space within the acoustic cavity. The optical waveguide at least partially includes an annular circumference that causes the light propagating within the optical waveguide to circulate on an ellipse or a circle.

9. An optical concentration measuring instrument for measuring the concentration of a target component in a gas, wherein, The optical concentration measuring device includes: A acoustic cavity having a gas inlet for containing gas introduced through the gas inlet; Optical components are disposed within the acoustic cavity; and A sound transducer is disposed within the acoustic cavity. The optical component has one or more light sources and one or more optical waveguides. The light sources emit light containing wavelengths absorbed by the object component. The optical waveguides are optically connected to the light sources, and the light from the light sources propagates inside the optical waveguides. At least a portion of the optical waveguides is exposed into the space within the acoustic cavity. The optical component has an optical filter that allows light of the specified wavelength from the light source to pass through and cuts off light of other wavelengths.

10. An optical concentration measuring instrument for measuring the concentration of a target component in a gas, wherein, The optical concentration measuring device includes: A acoustic cavity having a gas inlet for containing gas introduced through the gas inlet; Optical components are disposed within the acoustic cavity; and A sound transducer is disposed within the acoustic cavity. The optical component has one or more light sources and one or more optical waveguides. The light sources emit light containing wavelengths absorbed by the object component. The optical waveguides are optically connected to the light sources, and the light from the light sources propagates inside the optical waveguides. At least a portion of the optical waveguides is exposed into the space within the acoustic cavity. The optical component has a plurality of optical waveguides that are optically connected to one of the light sources.

11. An optical concentration measuring instrument for measuring the concentration of a target component in a gas, wherein, The optical concentration measuring device includes: A acoustic cavity having a gas inlet for containing gas introduced through the gas inlet; Optical components are disposed within the acoustic cavity; and A sound transducer is disposed within the acoustic cavity. The optical component has one or more light sources and one or more optical waveguides. The light sources emit light containing wavelengths absorbed by the object component. The optical waveguides are optically connected to the light sources, and the light from the light sources propagates inside the optical waveguides. At least a portion of the optical waveguides is exposed into the space within the acoustic cavity. The optical component has a plurality of light sources that are optically connected to one or more of the optical waveguides.

12. An optical concentration measuring instrument for measuring the concentration of a target component in a gas, wherein, The optical concentration measuring device includes: A acoustic cavity having a gas inlet for containing gas introduced through the gas inlet; Optical components are disposed within the acoustic cavity; and A sound transducer is disposed within the acoustic cavity. The optical component has one or more light sources and one or more optical waveguides. The light sources emit light containing wavelengths absorbed by the object component. The optical waveguides are optically connected to the light sources, and the light from the light sources propagates inside the optical waveguides. At least a portion of the optical waveguides is exposed into the space within the acoustic cavity. The average optical path length of the light from the light source that does not enter the optical waveguide but is radiated into the space within the acoustic cavity and reflected by the inner wall of the acoustic cavity is shorter than the effective optical path length of the optical waveguide.

13. The optical concentration measuring device according to any one of claims 1 to 12, wherein, The optical concentration measuring device has a 10mm... 3 The following volumes, The effective optical path length of the optical waveguide is 10 mm or more.

14. The optical concentration measuring device according to any one of claims 1 to 12, wherein, The average reflectivity of the inner wall of the acoustic cavity is below 70%.

15. The optical concentration measuring device according to any one of claims 1 to 12, wherein, The acoustic cavity has: The base portion has the optical components and the sound transducer disposed on its surface; and The cover portion has the gas inlet formed thereon and is installed on the base portion.

16. The optical concentration measuring device according to claim 15, wherein, The cover is bonded to the base, so that the internal space of the acoustic cavity is connected to the external space of the acoustic cavity only through the gas inlet.

17. The optical concentration measuring device according to claim 15, wherein, The base portion has a conductive portion. The conductive part includes: An inner contact end, formed on the surface, is electrically connected to at least one of the light source and the sound transducer; and The outer contact end is exposed to the external space of the acoustic cavity.

18. The optical concentration measuring device according to any one of claims 1 to 12, wherein, The optical concentration meter is equipped with a dust filter, which is installed at the gas inlet to seal the gas contained in the acoustic cavity.

19. The optical concentration measuring device according to any one of claims 1 to 12, wherein, The optical concentration measuring device includes a circuit disposed within the acoustic cavity and electrically connected to at least one of the light source and the sound transducer.

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