Odor detection device

Abstract

To provide a novel odor detection device capable of improving detection sensitivity by reducing the influence of gas expansion and contraction caused by heat resulting from light emission from a light-emitting means.SOLUTION: The odor detection device comprises at least a detection chamber 14 having a predetermined volume, a light-emitting means storage chamber 22 connected to the detection chamber, a light-emitting means 17 arranged in the light-emitting means storage chamber 22, and a pressure propagation suppression means 24 which isolates the detection chamber 14 from the light-emitting means storage chamber 22 to block pressure vibrations of the gas in the light-emitting means storage chamber and is also permeable.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an odor detection device that detects components of a gas (hereinafter sometimes referred to as gas) that causes an odor, and more particularly to an odor detection device that detects an odor using a photoacoustic sensor. [Background technology]

[0002] At manufacturing sites for fermented products such as miso and soy sauce, as well as at cosmetics manufacturing sites and food storage warehouses, smell (also known as aroma) is a quality control item, but it is difficult to implement digital transformation (DX).As a result, smell identification relies on the experience and senses of on-site workers, resulting in increased management and training costs.

[0003] Recently, attempts have been made to improve the efficiency of quality control through digitalization by using odor sensors to quantify odors (type of gas, concentration, etc.). Quantifying odors requires gas sensors that can detect gas components or odor components according to the purpose. For example, photoacoustic sensors using the photoacoustic effect, as described in Patent Document 1, have been proposed as sensors for detecting gas components and odor components.

[0004] The photoacoustic effect is a phenomenon in which, when light of a specific wavelength (laser light, LED light, etc.) is irradiated onto molecules of specific components that make up a gas, the molecules that absorb the light release heat, which causes them to expand and generate acoustic waves.Photoacoustic sensors can apply this acoustic effect to distinguish gases and scents, and because they are small and can detect gas components with high sensitivity, they are being applied to a variety of manufacturing sites. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-26652 Summary of the Invention [Problem to be solved by the invention]

[0006] The photoacoustic sensor works by repeatedly turning on and off light intermittently (in pulses), and then using a microphone to detect acoustic waves generated by the thermal expansion and contraction of molecules that absorb the light. Recently, there has been a demand for even greater detection sensitivity.

[0007] In this context, in a photoacoustic sensor, a pulsed electrical signal is applied to a light-emitting element, such as an infrared emitter or LED, to generate pulsed light. At this time, the light-emitting element and its drive circuit generate pulsed heat in synchronization with this, and this heat causes the gas surrounding the light-emitting element to expand and contract. This gas expansion and contraction is propagated as pressure vibrations through a housing surrounding the light-emitting element to a detection chamber filled with the gas to be detected.

[0008] Therefore, the expansion and contraction of the gas due to the heat generated by driving this component is synchronized with the expansion and contraction of the gas due to the photoacoustic effect in the detection chamber, making it difficult to separate the signal due to the photoacoustic effect from the signal due to the heat, resulting in unwanted noise, which creates the problem of not being able to improve detection sensitivity.

[0009] An object of the present invention is to provide a novel odor detection device that can improve detection sensitivity by reducing the influence of gas expansion and contraction caused by heat resulting from light emission from a light-emitting means. [Means for solving the problem]

[0010] The present invention is characterized in that the odor detection device comprises at least a detection chamber having a predetermined volume, a light-emitting means storage chamber connected to the detection chamber, a light-emitting means arranged in the light-emitting means storage chamber, and pressure propagation suppression means that isolates the detection chamber from the light-emitting means storage chamber, blocks or suppresses the propagation of pressure vibrations of the gas in the light-emitting means storage chamber, and is optically transparent. [Effects of the Invention]

[0011] According to the present invention, the influence of the expansion and contraction of gas due to heat caused by light emission from the light emitting means can be reduced, thereby improving detection sensitivity. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram illustrating the configuration of a conventional odor detection device. [Figure 2] 1 is a configuration diagram showing the configuration of a photoacoustic sensor according to a first embodiment of the present invention. [Figure 3] 3 is an explanatory diagram illustrating the relationship between the rigidity, thickness, and radius of the pressure propagation suppression means shown in FIG. 2. FIG. [Figure 4] FIG. 4 is a configuration diagram showing the configuration of a photoacoustic sensor according to a second embodiment of the present invention. [Figure 5] FIG. 10 is a configuration diagram showing the configuration of a photoacoustic sensor according to a third embodiment of the present invention. [Figure 6] FIG. 10 is a configuration diagram showing the configuration of a photoacoustic sensor according to a fourth embodiment of the present invention. [Figure 7] FIG. 10 is a configuration diagram showing the configuration of a photoacoustic sensor according to a fifth embodiment of the present invention. [Figure 8] FIG. 10 is a configuration diagram showing the configuration of a photoacoustic sensor according to a sixth embodiment of the present invention. [Figure 9] FIG. 10 is a configuration diagram showing the configuration of a photoacoustic sensor according to a seventh embodiment of the present invention. [Figure 10] FIG. 13 is a configuration diagram showing the configuration of a photoacoustic sensor according to an eighth embodiment of the present invention. [Figure 11] FIG. 13 is a configuration diagram showing the configuration of a photoacoustic sensor according to a ninth embodiment of the present invention. [Figure 12] FIG. 20 is an explanatory diagram illustrating the characteristics of an optical filter for carbon dioxide according to a tenth embodiment of the present invention. [Figure 13] FIG. 20 is an explanatory diagram illustrating the characteristics of an optical filter against water vapor according to a tenth embodiment of the present invention. [Figure 14] FIG. 22 is a configuration diagram showing the configuration of a photoacoustic sensor according to an eleventh embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiment, and various modifications and application examples within the technical concept of the present invention are also included within its scope.

[0014] First, the configuration, operation, and the above-mentioned problems of an odor detection device using a photoacoustic sensor will be briefly described.

[0015] In FIG. 1, the odor detection device OD includes at least a photoacoustic sensor 10. The photoacoustic sensor 10 is disposed on one surface (hereinafter referred to as the "surface") of a flat substrate (e.g., a resin substrate, etc.) 11. In particular, the photoacoustic sensor 10 is provided on the surface of the substrate 11 on which a control circuit and the like are mounted. In this way, the substrate 11 and the photoacoustic sensor 10 are integrated into an assembly as a whole. Therefore, this assembly can be incorporated into a box made of metal, synthetic resin, or the like, and assembled as an odor detection device.

[0016] The control circuit on the substrate 11 has the function of controlling the light emission frequency and light intensity of the light emitting means described below, and the function of measuring acoustic waves from the microphone 12. For this reason, by placing the photoacoustic cell 10 on the surface of the substrate 11 on which the control circuit is provided, connection wiring and the like is made easier.

[0017] The photoacoustic sensor 10 includes a housing 13 made of a metal or resin material, and a detection chamber 14 having a predetermined volume is formed inside the housing 13. The detection chamber 14 is a hollow space, and the shape of this space can be formed into a cylindrical shape or a rectangular parallelepiped shape. In this embodiment, which will be described later, the shape of the space is determined to be a cylindrical shape.

[0018] A through hole 15 that fluidly connects the detection chamber 14 to the outside is formed in a wall surface 13W of the housing 13 on the side opposite the substrate 11 from the detection chamber 14.

[0019] The number of through-holes 15 may be one or more, as long as they have an inflow area that allows the necessary amount of measurement gas to be smoothly introduced into the detection chamber 14. An open / close lid 16 is provided on the light-transmitting hole 15, which closes the light-transmitting hole 15 to prevent the pressure in the detection chamber 14 from escaping to the outside when the measurement gas is being detected.

[0020] Here, the outside refers to a space where the gas to be measured, such as the atmosphere, exists, and corresponds to the manufacturing site or storage warehouse described above. Therefore, the measurement gas present in the manufacturing site or storage warehouse flows into the detection chamber 14 through the through hole 15.

[0021] A light-emitting cell (corresponding to the light-emitting means in the claims) 17 is disposed within the detection chamber 14. The light-emitting cell 17 is composed of an LED element 18, which is a light-emitting element, a cell housing 19 that surrounds the LED element 18 from the outside, and an optical filter 20 provided in the cell housing 19.

[0022] The optical filter 20 and the LED element 18 are arranged so as to overlap in the light-emitting direction, and have the function of transmitting light of a predetermined wavelength from the LED element 18. In this example, an optical filter 20 that transmits infrared light is used.

[0023] The LED element 18 emits light in a pulsed manner at a predetermined frequency, thermally exciting a specific component Gas of the measurement gas in the detection chamber 14. The LED element 18 is provided on the front surface side of the substrate 11 and is controlled and driven by a control circuit (not shown). Note that instead of the LED element 18, a semiconductor laser or the like can also be used as the light emitting means.

[0024] A microphone 12 for measuring the intensity of the photoacoustic wave is disposed within the detection chamber 14. The microphone 12 is provided on the surface side of the substrate 11, and is controlled and driven by a control circuit (not shown). In this manner, the photoacoustic wave generated by the light emission of the LED element 18 is measured by the microphone 12, and the intensity of the photoacoustic wave measured by the microphone 12 is converted into an electrical signal. These processes are performed by a control circuit such as that shown in Patent Document 1, for example.

[0025] In the photoacoustic sensor 10 described above, a current is passed through the LED element 18 in a pulsating manner to generate light in a pulsating manner. Therefore, in synchronization with this, the LED element 18 and its drive circuit generate heat in a pulsating manner, and this heat causes the gas around the LED element 18 to expand and contract. This gas expansion and contraction is propagated as pressure vibrations through the cell housing 19 surrounding the LED element 18 to the detection chamber 14, which is filled with the gas to be detected.

[0026] This expansion and contraction of the gas due to heat is synchronized with the expansion and contraction of the gas due to the photoacoustic effect in the detection chamber 14, so the expansion and contraction of the gas due to the heat of the photoacoustic cell 17 becomes unwanted noise, which causes the problem of not being able to improve detection sensitivity.

[0027] In order to solve the above problems, the present invention proposes an odor detection device having the following configuration.

[0028] That is, the odor detection device comprises at least a detection chamber having a predetermined volume, a light-emitting means storage chamber connected to the detection chamber, a light-emitting means arranged in the light-emitting means storage chamber, and pressure propagation suppression means that isolates the detection chamber from the light-emitting means storage chamber, blocks or suppresses the propagation of pressure vibrations of the gas in the light-emitting means storage chamber, and is optically transparent.

[0029] This reduces the influence of gas expansion and contraction due to heat generated by light emitted by the light emitting means, thereby improving detection sensitivity.

[0030] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings of the following embodiments, the same reference numbers as those shown in Figure 1 indicate the same or similar components and parts, and therefore, explanations thereof will be omitted unless necessary. [Example]

[0031] The first embodiment of the present invention is characterized in that a light-emitting cell storage chamber containing a light-emitting cell is formed inside the detection chamber, and a pressure propagation suppression plate that blocks or suppresses the propagation of pressure vibrations of the gas in the light-emitting cell storage chamber and is also optically transparent is provided in the area connecting the detection chamber and the light-emitting cell storage chamber.

[0032] Details will be explained below based on the drawings, but the technical matters explained in this first embodiment are also technical matters in other embodiments described later, and may not be explained in other embodiments.

[0033] 2, a light emitting cell storage housing 21 that stores the light emitting cell 17 so as to surround it from the outside is provided in the internal space of the detection chamber 14. This light emitting cell storage housing 21 is disposed on the surface of the substrate 11. A light emitting cell storage chamber 22 is formed inside the light emitting cell storage housing 21, and an opening 23 through which infrared light that has passed through the optical filter 20 passes is provided in a part of the light emitting cell storage housing 21.

[0034] The opening 23 and the optical filter 20 are circular, and when viewed in the axial direction of the opening 23, the optical filter 20 exists within the projected area of ​​the opening 23. In other words, the opening 23 and the optical filter 20 are arranged on the same axis, and the diameter (D1) of the opening 23 is set larger than the diameter (D2) of the optical filter 20.

[0035] This allows most of the infrared light emitted and diffused from the optical filter 20 to enter the detection chamber 14. This helps stimulate the expansion and contraction of the gas to be detected within the detection chamber 14.

[0036] Furthermore, a light-transmitting pressure propagation suppression plate 24 is disposed on the side of the opening 23 facing the light-emitting cell storage chamber 22. The outer edge of the opening 23 of the light-emitting cell storage chamber 22 and the contact surface of the pressure propagation suppression plate 24 are bonded with an adhesive. In this way, because they are bonded on the side of the light-emitting cell storage chamber 22, the components of the adhesive are not exposed to the detection chamber 14, and it is possible to prevent unnecessary noise from being generated by the components of the adhesive.

[0037] The pressure vibration suppression plate 24 separates the detection chamber 14 from the light emitting cell storage chamber 22, blocking pressure vibrations of the gas in the light emitting cell storage chamber 22. For this reason, the pressure propagation suppression plate 24 is given the necessary rigidity to prevent it from bending due to pressure vibrations caused by the gas in the light emitting cell storage chamber 22.

[0038] The pressure propagation suppression plate 24 can be made of, for example, calcium fluoride (CaF2) or silicon (Si), and these materials have optical transparency. Furthermore, as described above, the pressure propagation suppression plate 24 is set to a predetermined thickness (t) so as not to bend due to pressure vibrations generated in the light-emitting cell storage chamber 22.

[0039] Furthermore, an anti-reflection film (AR coating) is formed on the surface of the pressure propagation suppression plate 24 on the side of the light-emitting cell storage chamber 22. This allows the light emitted from the LED element 18 to enter the detection chamber 14 without being reflected.

[0040] Meanwhile, a half mirror is formed on the surface of pressure propagation suppression plate 24 on the side of detection chamber 14. As a result, light emitted from LED element 18 and entering detection chamber 14 is reflected by wall surface 13W of housing 13 and then reflected again by the half mirror, thereby suppressing attenuation of light energy.

[0041] In addition, the spatial volume (V14) of the detection chamber 14 excluding the light emitting cell accommodating chamber 22 is formed to be larger than the spatial volume (V22) of the light emitting cell accommodating chamber 22. This is because even if pressure vibrations are transmitted from the light emitting cell accommodating chamber 22, the pressure vibrations can be alleviated due to the large spatial volume.

[0042] Here, the pressure vibration suppression plate 24 can be replaced with the optical filter 20. In this case, too, as described above, the optical filter 20 is provided with rigidity so as not to bend due to pressure vibrations of the gas in the light-emitting cell storage chamber 22. On the other hand, for the light-emitting cell 17, a light-transmitting sealing plate may be used instead of the optical filter 20.

[0043] In the above configuration, when the odor detection device OD is driven, the LED element 18 emits light in a pulsed manner, and only infrared light from the light is transmitted by the optical filter 20. The transmitted infrared light passes through the pressure propagation suppression plate 24 and is emitted into the detection chamber 14. The specific gas component to be measured in the detection chamber 14 repeatedly expands and contracts in response to the pulsed infrared light, generating acoustic waves. The generated acoustic waves are picked up by the microphone 12, which serves as an "acoustic sensor," and converted into an electrical signal. The gas is identified and its concentration is measured by a downstream control device.

[0044] During this measurement process, pressure vibrations caused by the expansion and contraction of gas in the light-emitting cell 17 due to heat generated by the light emission of the LED element 18 are transmitted to the light-emitting cell storage chamber 22 via the cell housing 19. This transmission causes pressure vibrations in the light-emitting cell storage chamber 22, but the light-emitting cell storage chamber 22 and the detection chamber 14 are isolated from each other by a pressure propagation suppression plate 24.

[0045] This pressure propagation suppression plate 24 is given rigidity so that it does not bend due to pressure vibrations, and therefore pressure vibrations within the light-emitting cell storage chamber 22 are blocked by the pressure propagation suppression plate 24, so that they are not propagated to the detection chamber 14, or their propagation is suppressed.

[0046] Next, the results of consideration of the material, radius, and thickness of the pressure propagation suppression means 24 will be described. A pressure propagation suppression means 24 is provided between the detection chamber and the light-emitting element housing chamber. This pressure propagation suppression means 24 is a light-transmitting object, but its physical size generates natural vibrations. In other words, depending on the size of the pressure propagation suppression means 24 and the modulation frequency of the odor sensor's light emission frequency (f), the suppression effect may be reduced or the noise intensity may increase due to resonance. Generally, the larger the size of the pressure propagation suppression means 24, the higher the natural frequency. The modulation range of the light emission frequency (f) of this type of odor sensor is 2 kHz or less. Therefore, it is necessary to size the pressure propagation suppression means 24 so that its natural vibration frequency does not occur within this range. In this embodiment, calcium fluoride (CaF2) is used as the material for the pressure propagation suppression means 24. The relationship between the radius and thickness of the pressure propagation suppression means 24 when a 2 kHz pressure vibration is applied is considered, and the results are shown in Figure 3. The pressure propagation suppression means 24 is circular in shape.

[0047] In Figure 3, the horizontal axis represents the thickness (mm) of the pressure propagation suppression means 24, and the vertical axis represents the radius (mm) of the pressure propagation suppression means 24. In this case, the radius is essentially the radius of the opening 23. As can be seen from Figure 3, when the modulation range of the pressure vibration is taken into consideration, the thickness and radius of the pressure propagation suppression means 24 should be determined so that the thickness is 0.4 mm or more and the radius is 20 mm or less. Note that if the shape of the opening 23 is a regular square, the length of the diagonal should be set to 20 mm or less.

[0048] As described above, according to the present embodiment, the influence of the expansion and contraction of gas due to heat generated by the light emission of the LED element can be reduced, thereby improving the detection sensitivity. [Example]

[0049] The second embodiment of the present invention is characterized in that a light emitting cell storage chamber storing light emitting cells is formed inside the detection chamber, and a pressure propagation suppression plate that blocks or suppresses the propagation of pressure vibrations of the gas in the light emitting cell storage chamber and is also optically transparent is provided in the area connecting the detection chamber and the light emitting cell storage chamber, and a through hole that connects the light emitting cell storage chamber to the outside and attenuates the pressure vibrations in the light emitting cell storage chamber is provided. Note that the through hole is formed in the light emitting cell storage casing.

[0050] Hereinafter, details will be described with reference to the drawings. However, the same reference numbers as those shown in FIG. 2 indicate the same or similar components and parts, and therefore, explanations thereof will be omitted unless necessary.

[0051] 4, the light emitting cell storage casing 21 that forms the light emitting cell storage chamber 22 and the casing 13 are integrally formed. A through hole 25 is formed in the area of ​​this integrated light emitting cell storage casing 21. This through hole 25 connects the space of the light emitting cell storage chamber 22 to the outside (here, the atmosphere). Since the through hole 25 is connected to the outside, it has the function of damping pressure vibrations that occur in the light emitting cell storage chamber 22.

[0052] In this way, since the pressure vibration can be damped by the through holes 25, the rigidity of the pressure propagation suppression plate 24 can be reduced, and as a result, the thickness of the pressure propagation suppression plate 24 can be reduced.

[0053] During the measurement process, pressure vibrations caused by the expansion and contraction of gas in the light emitting cell 17 due to heat generated by the light emission of the LED element 18 are transmitted to the light emitting cell storage chamber 22 via the cell housing 19. This transmission causes pressure vibrations in the light emitting cell storage chamber 22, but the light emitting cell storage chamber 22 and the detection chamber 14 are isolated by the pressure transmission suppression plate 24, and furthermore, the through hole 25 is connected to the outside, so transmission of the pressure vibrations to the detection chamber 14 is blocked or suppressed.

[0054] In this way, the pressure propagation suppression plate 24 is given rigidity so that it does not bend due to pressure vibrations, so that the pressure vibrations within the light-emitting cell storage chamber 22 are blocked by the pressure propagation suppression plate 24, and in addition, the pressure vibrations are attenuated by the through holes 25, so that the pressure vibrations within the light-emitting cell storage chamber 22 are not transmitted to the detection chamber 14, or their transmission is suppressed.

[0055] Therefore, according to this embodiment, the influence of the expansion and contraction of the gas due to the heat generated by the light emission of the LED element can be reduced, and the detection sensitivity can be improved. [Example]

[0056] The third embodiment of the present invention is characterized in that a light-emitting cell storage chamber containing a light-emitting cell is formed inside the detection chamber, and a pressure propagation suppression plate that blocks or suppresses the propagation of gas pressure vibrations in the light-emitting cell storage chamber and is also optically transparent is provided in the area connecting the detection chamber and the light-emitting cell storage chamber, and a through hole that connects the light-emitting cell storage chamber to the outside is provided in the substrate, which attenuates the pressure vibrations in the light-emitting cell storage chamber.

[0057] Hereinafter, details will be described with reference to the drawings. However, the same reference numbers as those shown in FIG. 2 indicate the same or similar components and parts, and therefore, explanations thereof will be omitted unless necessary.

[0058] 5, the light emitting cell storage housing 21 that forms the light emitting cell storage chamber 22 and the housing 13 are integrally formed. This integrated housing 13 is placed on the surface of the substrate 11. A through hole 26 is formed in the substrate 11. This through hole 26 connects the space of the light emitting cell storage chamber 22 to the outside (here, the atmosphere). Since the through hole 26 is connected to the outside, it has the function of damping pressure vibrations that occur in the light emitting cell storage chamber 22.

[0059] In this way, pressure vibrations can be attenuated by the through holes 26, so the rigidity of the pressure propagation suppression plate 24 can be reduced, and as a result, the thickness of the pressure propagation suppression plate 24 can be made thinner.

[0060] During the measurement process, pressure vibrations caused by the expansion and contraction of gas in the light emitting cell 17 due to heat generated by the light emission of the LED element 18 are transmitted to the light emitting cell storage chamber 22 via the cell housing 19. This transmission causes pressure vibrations in the light emitting cell storage chamber 22, but the light emitting cell storage chamber 22 and the detection chamber 14 are isolated by the pressure transmission suppression plate 24, and furthermore, the through hole 26 is connected to the outside, so transmission of the pressure vibrations to the detection chamber 14 is blocked or suppressed.

[0061] In this way, the pressure propagation suppression plate 24 is given rigidity so that it does not bend due to pressure vibrations, so that the pressure vibrations within the light-emitting cell storage chamber 22 are blocked by the pressure propagation suppression plate 24.In addition, the pressure vibrations are attenuated by the through holes 26, so that the pressure vibrations within the light-emitting cell storage chamber 22 are not transmitted to the detection chamber 14, or their transmission is suppressed.

[0062] Therefore, according to this embodiment, the influence of the expansion and contraction of the gas due to the heat generated by the light emission of the LED element can be reduced, and the detection sensitivity can be improved. [Example]

[0063] The fourth embodiment of the present invention is characterized in that a light-emitting cell storage chamber containing a light-emitting cell is formed inside the detection chamber, and a pressure propagation suppression plate that blocks or suppresses the propagation of pressure vibrations of the gas in the light-emitting cell storage chamber and is also optically transparent is provided in the area connecting the detection chamber and the light-emitting cell storage chamber, and the adhesive location of the pressure propagation suppression means is provided on the side of the light-emitting storage chamber.

[0064] Hereinafter, detailed explanations will be given based on the drawings, but the same reference numbers as those shown in Fig. 2 indicate the same or similar components and parts, and therefore explanations will be omitted unless necessary. Note that in this embodiment, the embodiment shown in Fig. 4 is shown for convenience.

[0065] In Figure 6, a light-transmitting pressure propagation suppression plate 24 is disposed on the side of the opening 23 facing the light-emitting cell storage chamber 22. The outer edge of the opening 23 of the light-emitting cell storage chamber 22 and the contact surface of the pressure propagation suppression plate 24 are bonded with an adhesive 27. Because the pressure propagation suppression plate 24 is bonded on the side facing the light-emitting cell storage chamber 22 in this way, the components of the adhesive are not exposed to the detection chamber 14, and it is possible to prevent unnecessary noise from being generated by the components of the adhesive. Note that the adhesive 27 is exaggerated in the drawing, so that it appears as if the adhesive 27 is exposed, but in reality the thickness of the adhesive 27 is thin and it is considered that it is not substantially exposed to the detection chamber 14.

[0066] As mentioned above, the infrared light emitted from the light-emitting cell 17 is diffused to the surroundings. Therefore, it is necessary to allow as much infrared light as possible to enter the detection chamber 14.

[0067] Therefore, in this embodiment, the center of the opening 23 and the center of the light-emitting cell 17 (here, the center of the optical filter 20) are arranged on the same axis (C), and the diameter (D1) of the opening 23 is made larger than the diameter (D2) of the optical filter 20, as shown in Fig. 2. This allows most of the infrared light emitted from the optical filter 20 to enter the detection chamber 14, increasing the intensity of the acoustic wave and improving the gas detection sensitivity.

[0068] Furthermore, if the axial distance between the optical filter 20 and the opening 23 is short, the diameter (D1) of the opening 23 is made short, and if the axial distance between the optical filter 20 and the opening 23 is long, the diameter (D1) of the opening 23 is made long.

[0069] In this embodiment as well, the influence of gas expansion and contraction due to heat generated by light emission from the LED elements can be reduced, thereby improving detection sensitivity. [Example]

[0070] The fifth embodiment of the present invention is characterized in that a detection chamber, a pressure vibration damping chamber, and a light-emitting cell storage chamber that stores a light-emitting cell are formed, and a pressure propagation suppression plate that blocks or suppresses the propagation of pressure vibrations of the gas in the light-emitting cell storage chamber and is also optically transparent is provided in the area connecting the detection chamber and the pressure vibration damping chamber, and an optical filter that transmits specific light from the light-emitting cell is provided in the area connecting the pressure vibration damping chamber and the light-emitting cell storage chamber. Note that the optical filter is removed from the light-emitting cell.

[0071] Hereinafter, details will be described with reference to the drawings. However, the same reference numbers as those shown in FIGS. 2 to 6 denote the same or similar constituent elements and parts, and therefore descriptions thereof will be omitted unless necessary.

[0072] 7, three spaces, namely, the detection chamber 14, the pressure vibration damping chamber 28, and the light emitting cell storage chamber 22, are formed inside the housing 13. Here, the pressure vibration damping chamber 28 and the light emitting cell storage chamber 22 are integrally formed in this order in the direction of the central axis (C) inside the housing 13. Furthermore, the pressure vibration damping chamber 28 and the light emitting cell storage chamber 22 are cylindrical in shape.

[0073] The substrate 11 is attached to the opening side of the light emitting cell storage chamber 22. Here, the diameters of the pressure vibration damping chamber 28 and the light emitting cell storage chamber 22 are in the relationship of "pressure vibration damping chamber 28 < light emitting cell storage chamber 22", which makes it possible to cut the inside of the housing 13 from the substrate 11 side with a cutting tool and form each space in order.

[0074] In addition, a pressure propagation suppression plate 29 that blocks or suppresses the propagation of pressure vibrations of the gas in the light emitting cell storage chamber 22 and is optically transparent is provided in the region connecting the detection chamber 14 and the pressure vibration damping chamber 28.

[0075] Furthermore, an optical filter 30 that transmits specific light (infrared light in this case) from the light-emitting cell 17 arranged in the light-emitting cell storage chamber 22 is provided in the region connecting the pressure vibration damping chamber 28 and the light-emitting cell storage chamber 22. This optical filter 30 replaces the optical filter 20 that was provided in the light-emitting cell 17.

[0076] Here, the pressure propagation suppression plate 29 and the optical filter 30 can be replaced with an inverse relationship.

[0077] The diameters of the pressure propagation suppression plate 29 and the optical filter 30 (here synonymous with the diameter of the opening) are determined to match the openings of their respective connection regions. In other words, the diameter of the pressure propagation suppression plate 29 is shorter than the diameter of the pressure vibration damping chamber 28, centered on the central axis (C). Furthermore, the diameter of the optical filter 30 is longer than the diameter of the pressure vibration damping chamber 28, but shorter than the diameter of the pressure vibration damping chamber 28. This allows the pressure propagation suppression plate 29 and the optical filter 30 to be assembled in that order.

[0078] Here, in the first to fourth embodiments, the optical filter is integrated with the light emitting cell 17, but in the present embodiment, the optical filter 30 of the light emitting cell 17 is separated and provided in the region connecting the pressure vibration damping chamber 28 and the light emitting cell storage chamber 22. Also, as mentioned above, in order to attenuate pressure vibrations, a through hole 25 is formed in the pressure vibration damping chamber 28, and a through hole 26 is formed in the substrate 11 of the light emitting cell storage chamber 22.

[0079] In this embodiment as well, the influence of gas expansion and contraction due to heat generated by light emission from the LED elements can be reduced, thereby improving detection sensitivity. [Example]

[0080] The sixth embodiment of the present invention is characterized in that a detection chamber, a pressure vibration damping chamber, and a light-emitting cell storage chamber containing a light-emitting cell are formed in axial order, and a pressure propagation suppression plate that blocks or suppresses the propagation of pressure vibrations of the gas in the light-emitting cell storage chamber and is also optically transparent is provided in the area connecting the detection chamber and the pressure vibration damping chamber, and an optical filter that transmits specific light from the light-emitting cell is provided in the area connecting the pressure vibration damping chamber and the light-emitting cell storage chamber.

[0081] Hereinafter, details will be described with reference to the drawings. However, the same reference numbers as those shown in FIGS. 2 to 6 denote the same or similar constituent elements and parts, and therefore descriptions thereof will be omitted unless necessary.

[0082] 8, three spaces, namely, the detection chamber 14, the pressure vibration damping chamber 28, and the light-emitting cell storage chamber 22, are formed coaxially with respect to the central axis (C) inside the housing 13. The three spaces 14, 28, and 22 are integrally formed in order in the direction of the central axis (C) inside the housing 13. Here, the three spaces 14, 28, and 22 are cylindrical in shape, and the spatial volumes have the relationship "detection chamber 14<pressure vibration damping chamber 28<light-emitting cell storage chamber 22".

[0083] The substrate 11 is attached to the opening side of the light emitting cell storage chamber 22. Here, the diameters of the detection chamber 14, the pressure vibration damping chamber 28, and the light emitting cell storage chamber 22 have the following relationship: "detection chamber 14 < pressure vibration damping chamber 28 < light emitting cell storage chamber 22", and this makes it possible to cut the inside of the housing 13 from the substrate 11 side with a cutting tool and form each space in order.

[0084] Furthermore, if the housing 13 is made of metal, it can be pressed, or if it is made of synthetic resin, it can be injection molded, and the detection chamber 14, pressure vibration damping chamber 28, and light emitting cell storage chamber 22 can be formed taking into consideration the die-cutting process.

[0085] In addition, a pressure propagation suppression plate 29 that blocks or suppresses the propagation of pressure vibrations of the gas in the light emitting cell storage chamber 22 and is optically transparent is provided in the region connecting the detection chamber 14 and the pressure vibration damping chamber 28.

[0086] Furthermore, an optical filter 30 that transmits specific light (infrared light in this case) from the light-emitting cells 17 arranged in the light-emitting cell storage chamber 22 is provided in the region connecting the pressure vibration damping chamber 28 and the light-emitting cell storage chamber 22. Here, it is also possible to replace the pressure propagation suppression plate 29 and the optical filter 30 in an inverse relationship.

[0087] The diameters of the pressure propagation suppression plate 29 and the optical filter 30 are determined to fit the openings of their respective connection regions. That is, the diameter of the pressure propagation suppression plate 29 is longer than the diameter of the detection chamber 14 and shorter than the diameter of the pressure vibration damping chamber 28. Furthermore, the diameter of the optical filter 30 is longer than the diameters of the detection chamber 14 and the pressure vibration damping chamber 28 and shorter than the diameter of the light-emitting cell accommodating chamber 22. This allows the pressure propagation suppression plate 29 and the optical filter 30 to be assembled in order from the substrate 11 side.

[0088] Here, in the first to fourth embodiments, the optical filter is integrated with the light emitting cell 17, but in the present embodiment, the optical filter 30 of the light emitting cell 17 is separated and provided in the region connecting the pressure vibration damping chamber 28 and the light emitting cell storage chamber 22. Also, as mentioned above, in order to attenuate pressure vibrations, a through hole 25 is formed in the pressure vibration damping chamber 28, and a through hole 26 is formed in the substrate 11 of the light emitting cell storage chamber 22.

[0089] In this embodiment, the housing 13 of the detection chamber 14 is provided with a communication hole 31 that connects the detection chamber 14 to the outside, and the microphone 12 is provided at the end on the outside side. The microphone 12 is also provided with a microphone board 32. In this way, since the microphone 12 is provided outside the detection chamber 14, the spatial volume of the detection chamber 14 can be reduced, and the detection response of the acoustic wave can be improved.

[0090] In this embodiment as well, the influence of gas expansion and contraction due to heat generated by light emission from the LED elements can be reduced, thereby improving detection sensitivity. [Example]

[0091] The seventh embodiment of the present invention is a modification of the sixth embodiment, and is characterized in that the detection chamber, the pressure vibration damping chamber, and the light-emitting cell storage chamber containing the light-emitting cell are formed in axial order, and a pressure propagation suppression plate that blocks or suppresses the propagation of pressure vibrations of the gas in the light-emitting cell storage chamber and is also optically transparent is provided in the area connecting the detection chamber and the pressure vibration damping chamber, and an optical filter that transmits specific light from the light-emitting cell is provided in the area connecting the pressure vibration damping chamber and the light-emitting cell storage chamber, and the relationship in diameter between the detection chamber, the pressure vibration damping chamber, and the light-emitting cell storage chamber is the opposite of that in the embodiment of Figure 7.

[0092] Hereinafter, the details will be described with reference to the drawings. However, the same reference numbers as those in FIG. 8 indicate the same or similar components and parts, and therefore, the description will be omitted unless necessary.

[0093] 9, three spaces, namely, the detection chamber 14, the pressure vibration damping chamber 28, and the light-emitting cell storage chamber 22, are formed coaxially with respect to the central axis (C) inside the housing 13. The three spaces 14, 28, and 22 are integrally formed in order in the direction of the central axis (C) inside the housing 13. Here, the three spaces 14, 28, and 22 are cylindrical in shape, and the spatial volumes have the relationship "detection chamber 14 > pressure vibration damping chamber 28 > light-emitting cell storage chamber 22."

[0094] The substrate 11 is attached to the opening side of the light-emitting cell storage chamber 22. Here, the diameters of the detection chamber 14, the pressure vibration damping chamber 28, and the light-emitting cell storage chamber 22 have the following relationship: "detection chamber 14 > pressure vibration damping chamber 28 > light-emitting cell storage chamber 22," which makes it possible to cut the inside of the casing 13 from the opposite side of the substrate 11 using a cutting tool to form each space in order. In this case, the wall portion 13Wa of the casing 13 on the opposite side of the substrate 11 is removed in advance.

[0095] Furthermore, if the housing 13 is made of metal, it can be pressed, or if it is made of synthetic resin, it can be injection molded, and the detection chamber 14, pressure vibration damping chamber 28, and light emitting cell storage chamber 22 can be formed taking into account the mold removal process.

[0096] In addition, a pressure propagation suppression plate 29 that blocks or suppresses the propagation of pressure vibrations of the gas in the light emitting cell storage chamber 22 and is optically transparent is provided in the region connecting the detection chamber 14 and the pressure vibration damping chamber 28.

[0097] Furthermore, an optical filter 30 that transmits specific light (infrared light in this case) from the light-emitting cells 17 arranged in the light-emitting cell storage chamber 22 is provided in the region connecting the pressure vibration damping chamber 28 and the light-emitting cell storage chamber 22. Here, it is also possible to replace the pressure propagation suppression plate 29 and the optical filter 30 in an inverse relationship.

[0098] The diameters of the pressure propagation suppression plate 29 and the optical filter 30 are determined to fit the openings of their respective connection regions. That is, the diameter of the pressure propagation suppression plate 29 is shorter than the diameter of the detection chamber 14 and longer than the diameter of the pressure vibration damping chamber 28. Furthermore, the diameter of the optical filter 30 is shorter than the diameters of the detection chamber 14 and the pressure vibration damping chamber 28 and longer than the diameter of the light-emitting cell accommodating chamber 22. This allows the pressure propagation suppression plate 29 and the optical filter 30 to be assembled in order from the side opposite the substrate 11.

[0099] Here, in embodiments 1 to 4, the optical filter is integrated with the light emitting cell 17, but in this embodiment, the optical filter 30 of the light emitting cell 17 is separated and provided in the area connecting the pressure vibration damping chamber 28 and the light emitting cell storage chamber 22.

[0100] In this embodiment, the spatial volumes of the light-emitting cell storage chamber 22 and the pressure vibration damping chamber 28 leading to the detection chamber 14 are gradually increased compared to the embodiment of Figure 8, and accordingly, pressure vibrations can be damped.

[0101] Furthermore, even if the light from the light-emitting cell 17 diffuses (spreads), the diameters of the optical filter 30 and the pressure vibration suppression plate 29 increase in stages, so that a sufficient amount of light can enter the detection chamber 14.

[0102] In this embodiment as well, the influence of gas expansion and contraction due to heat generated by light emission from the LED elements can be reduced, thereby improving detection sensitivity. [Example]

[0103] The eighth embodiment of the present invention is characterized in that a detection chamber, a pressure vibration damping chamber, and a light-emitting cell storage chamber containing a light-emitting cell are formed inside the housing, and a pressure propagation suppression plate that blocks or suppresses the propagation of pressure vibrations of the gas in the light-emitting cell storage chamber and is also optically transparent is provided in the area connecting the detection chamber and the pressure vibration damping chamber, and an optical filter that transmits specific light from the light-emitting cell is provided in the area connecting the pressure vibration damping chamber and the light-emitting cell storage chamber, and further a space that generates Helmholtz resonance and is connected to the detection chamber is formed inside the housing.

[0104] Details will be explained below with reference to the drawings. In this embodiment, a modified configuration of the configuration shown in FIG. 9 is employed as an example. The modified configuration has a spatial volume relationship of "detection chamber 14 > light emitting cell storage chamber 22 > pressure vibration damping chamber 28." Therefore, the same reference numbers as those shown in FIG. 9 indicate the same or frequently occurring components or parts, and therefore explanations will be omitted unless necessary.

[0105] 10, a first communication passage 31 and a second communication passage 33 connected to the first communication passage 31 so as to intersect at right angles are formed inside the housing 13. One end of the first communication passage 31 is fluidly connected to the detection chamber 14, and the other end of the first communication passage 31 is fluidly connected to one end of the second communication passage 33. The other end of the second communication passage 33 is connected to the microphone 12.

[0106] The conduit formed by the first communication passage 31 and the second communication passage 33 is a resonance space (resonance tube) that generates Helmholtz resonance. Therefore, the acoustic waves generated in the detection chamber 14 are amplified by the resonance tube formed by the first communication passage 31 and the second communication passage 33, thereby improving detection sensitivity. Needless to say, a resonance tube that generates Helmholtz resonance can be added even to embodiments other than those having the configuration shown in FIG. 10.

[0107] Other functions and effects are the same as those of the first to seventh embodiments described above, so a description thereof will be omitted.

[0108] In this embodiment as well, the influence of gas expansion and contraction due to heat generated by light emission from the LED elements can be reduced, thereby improving detection sensitivity. [Example]

[0109] The ninth embodiment of the present invention is characterized in that a detection chamber, a pressure vibration damping chamber, and a light-emitting cell storage chamber containing a light-emitting cell are formed in axial order inside the housing, and a pressure propagation suppression plate that blocks pressure vibrations of the gas in the light-emitting cell storage chamber and is also optically transparent is provided in the area connecting the detection chamber and the pressure vibration damping chamber, and an optical filter that transmits specific light from the light-emitting cell is provided in the area connecting the pressure vibration damping chamber and the light-emitting cell storage chamber, and a space that generates Helmholtz resonance is further formed inside the housing.

[0110] The details will be described below with reference to the drawings, and in this embodiment, the configuration shown in Fig. 9 is used as an example. Therefore, the same reference numbers as those shown in Fig. 9 indicate the same or similar components and parts, and therefore descriptions thereof will be omitted unless necessary.

[0111] 11, a first communication passage 31 and a second communication passage 33 connected to the first communication passage 31 so as to intersect at right angles are formed inside the housing 13. One end of the first communication passage 31 is fluidly connected to the detection chamber 14, and the other end of the first communication passage 31 is fluidly connected to one end of the second communication passage 33. The other end of the second communication passage 33 is connected to the microphone 12.

[0112] The conduit formed by the first communication passage 31 and the second communication passage 33 is a resonance space (resonance tube) that generates Helmholtz resonance. Therefore, the acoustic waves generated in the detection chamber 14 are amplified by the resonance tube formed by the first communication passage 31 and the second communication passage 33, thereby improving detection sensitivity.

[0113] In this embodiment, the spatial volumes of the light emitting cell storage chamber 22 and the pressure vibration damping chamber 28 leading to the detection chamber 14 are formed to gradually increase, so that the pressure vibration can be damped accordingly. Furthermore, even if the light from the light emitting cell 17 diffuses (spreads), the diameters of the optical filter 30 and the pressure vibration suppression plate 29 increase stepwise, so that a sufficient amount of light can be incident on the detection chamber 14.

[0114] Other functions and effects are the same as those of the first to eighth embodiments described above, and therefore description thereof will be omitted.

[0115] In this embodiment as well, the influence of gas expansion and contraction due to heat generated by light emission from the LED elements can be reduced, thereby improving detection sensitivity. [Example]

[0116] The tenth embodiment of the present invention is characterized in that a detection chamber, a pressure vibration damping chamber, and a light-emitting cell storage chamber containing a light-emitting cell are formed inside the housing, and a first optical filter that suppresses the transmission of a first specific light from the light-emitting cell is provided in the area connecting the pressure vibration damping chamber and the light-emitting cell storage chamber, and a second optical filter that blocks or suppresses the propagation of pressure vibrations of the gas in the light-emitting cell storage chamber and also suppresses the transmission of a second specific light is provided in the area connecting the pressure vibration damping chamber and the detection chamber.

[0117] For example, when detecting molecules of a specific gas component in the atmosphere, since the atmosphere contains a large amount of carbon dioxide (CO2) and water vapor (H2O), it is necessary to exclude light that reacts with these. For this purpose, for example, the pressure vibration suppression plate 29 in Figure 11 can be replaced with an optical filter 29, and the optical filter 29 and optical filter 30 can be used to suppress the transmission of light that reacts with carbon dioxide and water vapor.

[0118] In Figure 12, the wavelength of light to which carbon dioxide reacts is in the 4.3 μm band, so this band is the absorption wavelength of carbon dioxide. Therefore, if an optical filter with a large transmission loss in the 4.3 μm band is used, it is possible to exclude the light to which carbon dioxide reacts.

[0119] 13, the wavelengths of light to which water vapor reacts are the 2.7 μm and 6.5 μm bands, and these bands are the absorption wavelengths of water vapor. Therefore, by using an optical filter with large transmission losses in the 2.7 μm and 6.5 μm bands, it is possible to exclude the light to which water vapor reacts.

[0120] In this way, when measuring specific components in the atmosphere, it is possible to eliminate light that reacts with carbon dioxide and water vapor, thereby improving detection accuracy. Note that the optical filters 29 and 30 of this embodiment are not limited to bands corresponding to carbon dioxide and water vapor, and may also be used for other gas components. [Example]

[0121] The eleventh embodiment of the present invention is characterized in that a detection chamber and a light-emitting cell storage chamber containing a plurality of (here, two) light-emitting cells are formed inside the housing, and a pressure propagation suppression plate that blocks or suppresses the propagation of gas pressure vibrations in the light-emitting cell storage chamber and is also optically transparent is provided in the area connecting the detection chamber and the light-emitting cell storage chamber, and each light-emitting cell is driven in a time-division manner.

[0122] Hereinafter, details will be described with reference to the drawings. However, the same reference numbers as those shown in FIGS. 2 to 11 denote the same or similar constituent elements and parts, and therefore descriptions thereof will be omitted unless necessary.

[0123] 14, two light emitting cells 17A, 17B are arranged inside the light emitting cell storage chamber 22. As described above, each of the light emitting cells 17A, 17B includes a cell housing 19A, 19B, an LED element 18A, 18B, and an optical filter 20A, 20B. The other end of the second communication passage 33 is connected to the large diameter portion 34, and the microphone 12 is stored in the large diameter portion 34.

[0124] Here, optical filter 20A and optical filter 20B transmit different wavelengths of light corresponding to the gas components to be measured. Therefore, measurement of gas components by light emitting cell 17A and measurement of gas components by light emitting cell 17B cannot be performed simultaneously. For this reason, in this embodiment, for example, a mode of measuring gas components by light emitting cell 17A and a mode of measuring gas components by light emitting cell 17B are alternately performed to measure multiple gas components.

[0125] In this case, the influence of the expansion and contraction of the gas due to the heat generated by the light emitted from the LED element can be reduced, and the detection sensitivity can be improved, as described in the previous embodiment.

[0126] As described above, the present invention is characterized in that the odor detection device comprises at least a detection chamber having a predetermined volume, a light-emitting means storage chamber connected to the detection chamber, a light-emitting means arranged in the light-emitting means storage chamber, and pressure propagation suppression means that isolates the detection chamber from the light-emitting means storage chamber, blocks or suppresses the propagation of pressure vibrations of the gas in the light-emitting means storage chamber, and is optically transparent.

[0127] This reduces the influence of gas expansion and contraction due to heat generated by light emitted by the light emitting means, thereby improving detection sensitivity.

[0128] The present invention is not limited to the above-described embodiments, but includes various modifications. The above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace other configurations with respect to the configuration of each embodiment. [Explanation of symbols]

[0129] 10...Photoacoustic sensor, 11...Substrate, 12...Microphone, 13...Housing, 14...Detection chamber, 17...Light-emitting cell, 18LED element, 19...Cell housing, 20, 30...Optical filter, 21...Light-emitting cell storage housing, 22...Light-emitting cell storage chamber, 23...Opening, 24, 29...Pressure propagation suppression plate

Claims

1. a detection chamber having a predetermined volume; a light-emitting means storage chamber connected to the detection chamber; a light emitting means disposed in the light emitting means storage chamber; a pressure propagation suppression means for isolating the detection chamber from the light emitting means storage chamber, blocking or suppressing the propagation of pressure vibrations of the gas in the light emitting means storage chamber, and having optical transparency; An odor detection device comprising:

2. The odor detection device according to claim 1, The light emitting means is composed of a light emitting element, a housing surrounding the light emitting element, and an optical filter that transmits specific light from the light emitting element. An odor detection device characterized by:

3. The odor detection device according to claim 2, The light emitting means storage chamber for storing the light emitting means is formed inside the detection chamber, A pressure propagation suppression plate that blocks or suppresses the propagation of pressure vibrations of the gas in the light-emitting means storage chamber and is optically transparent is disposed in the region connecting the detection chamber and the light-emitting means storage chamber. An odor detection device characterized by:

4. The odor detection device according to claim 3, A through hole is provided that connects the light emitting means storage chamber with the outside and attenuates pressure vibrations in the light emitting means storage chamber. An odor detection device characterized by:

5. The odor detection device according to claim 2, The pressure propagation suppression means is disposed on the side of the light-emitting means storage chamber, and the pressure propagation suppression means is adhered to the light-emitting means storage chamber with an adhesive. An odor detection device characterized by:

6. forming a detection chamber having a predetermined volume, a pressure vibration damping chamber having a predetermined volume, and a light emitting means storage chamber having a predetermined volume and storing a light emitting means; a pressure propagation suppression plate that blocks or suppresses the propagation of pressure vibration of the gas in the light-emitting means storage chamber and that is optically transparent is provided in an area connecting the detection chamber and the pressure vibration damping chamber; An optical filter that transmits specific light from the light emitting means is provided in the region connecting the pressure vibration damping chamber and the light emitting means storage chamber. An odor detection device characterized by:

7. The odor detection device according to claim 6, The light emitting means is composed of a light emitting element and a housing that surrounds it. An odor detection device characterized by:

8. The odor detection device according to claim 7, the detection chamber, the pressure vibration damping chamber, and the light emitting means accommodating chamber are formed in this order in the axial direction, The pressure propagation suppression plate is provided in an area connecting the detection chamber and the pressure vibration damping chamber, and the pressure propagation suppression plate blocks or suppresses the propagation of pressure vibration of the gas in the light emitting means storage chamber and is optically transparent; An optical filter that transmits specific light from the light emitting means is provided in the region connecting the pressure vibration damping chamber and the light emitting means storage chamber. An odor detection device characterized by:

9. The odor detection device according to claim 8, The diameter of the detection chamber, the diameter of the pressure vibration damping chamber, and the diameter of the light emitting means accommodating chamber are determined to have a relationship of "diameter of the detection chamber < diameter of the pressure vibration damping chamber < diameter of the light emitting means accommodating chamber", or "diameter of the detection chamber > diameter of the pressure vibration damping chamber > diameter of the light emitting means accommodating chamber". An odor detection device characterized by:

10. The odor detection device according to claim 1 or claim 6, A resonance tube that generates Helmholtz resonance is connected to the detection chamber, and acoustic waves are detected via the resonance tube. An odor detection device characterized by:

11. The odor detection device according to claim 6, a first optical filter that suppresses transmission of a first specific light from the light emitting means is provided in a region connecting the pressure vibration damping chamber and the light emitting means housing chamber; A second optical filter is provided in a region connecting the pressure vibration damping chamber and the detection chamber, which blocks or suppresses the propagation of pressure vibration of the gas in the light emitting means storage chamber and further suppresses the transmission of a second specific light. An odor detection device characterized by:

12. forming a detection chamber and a light emitting means storage chamber storing a plurality of light emitting means; a pressure propagation suppression plate that blocks or suppresses the propagation of pressure vibrations of the gas in the light-emitting means storage chamber and that is optically transparent is provided in an area connecting the detection chamber and the light-emitting means storage chamber; Each of the light emitting means is composed of a light emitting element, a housing surrounding the light emitting element, and an optical filter that transmits light of different wavelengths, Each of the light emitting means is driven in a time-division manner. An odor detection device characterized by:

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