Optical sensor device

Abstract

An optical sensor device includes a sensing element and an elastic sealing member. The sensing element comprises a prism which comprises a bevel edge surface and two right-angle edge surfaces; and a sensing film on the beveled side. The sensing film is exposed to an airtight space including a target substance. A limiting wall defining the airtight space has an opening, and the opening is covered by the sensing element. The resilient sealing member is located between the sensing element and the opening. The sensing element is fixed by being pressed by a fixing member. Light passes through one of the two right-angle side surfaces and is incident on the sensing film. The light reflected from the sensing film passes through the other one of the two right-angle side surfaces and is emitted. A photodetector detects light reflected from the sensing film and emitted through the other of the two right-angle side surfaces.

Description

Technical Field

[0001] The present invention relates to optical sensor devices. Background Art

[0002] Sensor devices have been developed for detecting specific types of chemicals and their concentrations; for example, gas sensor devices have been developed for detecting hydrogen leaks. Although various types of hydrogen sensors with different sensing schemes are known, in order to obtain higher response speeds or cleaning effects, common types of sensors need to be operated at high temperatures. Such hydrogen sensors that need to operate at high temperatures are required to eliminate the possibility of explosion caused by overcurrent or sparks in the circuit coming into contact with hydrogen.

[0003] A scheme for sensing hydrogen by an optical method is known; for example, a gas sensor device of a photoelectric detection type using surface plasmon resonance is known. At the same time, a metal layer formed on a glass substrate is used as a sensing layer, and a technique of optically matching the lower surface of the glass substrate and a prism is used with optical coupling oil. The sensing layer is illuminated through the prism, and light reflected from the sensing layer passes through the prism and is detected by an external photodetector. The prism reduces the light reflected from the glass substrate and reaching the photodetector. Summary of the invention

[0004] A sensing element constructed in such a way that a laminated gas sensing film (also referred to as a gas sensing film) is formed on a transparent substrate with a prism can be used to test fluids (including gases and liquids). For testing, the sensing film of the sensing element must be exposed to the test object (fluid). Other components including a light source and a photodetector need to be located outside the test object. It is required to enclose the test object in an airtight space so that the test object does not escape from the airtight space or ambient air does not enter the airtight space.

[0005] One aspect of the present invention is an optical sensor device, comprising: a light source; a sensing element; a photodetector; a fixing member; and an elastic sealing member, wherein the sensing element comprises: a prism, the prism comprising a hypotenuse surface and two right-angled surface; and a sensing film on the hypotenuse surface, the sensing film being configured to sense a target substance, wherein the sensing film is exposed to an airtight space including the target substance, wherein a limiting wall defining the airtight space including the target substance has an opening, and the opening is covered by the sensing element, wherein the elastic sealing member is located between the sensing element and the opening. The sensing element is fixed by being pressed by the fixing member, and the pressing strength causes the elastic sealing member to deform elastically, wherein the light source and the photodetector are located outside the airtight space including the target substance, wherein the light from the light source is configured to pass through one of the two right-angled edges and be incident on the sensing film, wherein the light reflected from the sensing film is configured to be emitted through the other of the two right-angled edges, and wherein the photodetector is configured to detect the light reflected from the sensing film and emitted through the other of the two right-angled edges.

[0006] One aspect of the present invention enables suitable testing of fluids using a sensing element comprising a prism.

[0007] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 Schematic diagram showing a hydrogen gas measuring method of a hydrogen gas sensor device according to one embodiment of the present specification.

[0009] Figure 2 A configuration example of a hydrogen gas sensor device in one embodiment of the present specification is schematically shown.

[0010] Figure 3A is a diagram showing the structure of a prism.

[0011] Figure 3B is another diagram showing the structure of a prism.

[0012] Figure 4 is a cross-sectional view schematically showing one configuration example of a sensing element in an embodiment of the present specification.

[0013] Figure 5 is a cross-sectional view schematically showing another configuration example of the sensing element in the embodiment of the present specification.

[0014] Figure 6An example of configuration and use of the hydrogen sensor device in the embodiment of this specification is shown.

[0015] Fig. 7A An example of an airtight structural assembly utilizing a sensing element in a hydrogen sensor device and an example of assembling the airtight structural assembly are shown.

[0016] Figure 7B An example of an airtight structural assembly utilizing a sensing element in a hydrogen sensor device and an example of assembling the airtight structural assembly are shown.

[0017] Figure 7C An example of an airtight structural assembly utilizing a sensing element in a hydrogen sensor device and an example of assembling the airtight structural assembly are shown.

[0018] Fig.7D An example of an airtight structural assembly utilizing a sensing element in a hydrogen sensor device and an example of assembling the airtight structural assembly are shown.

[0019] Fig. 8A An example of an assembly including a channel block and a sensing element holder attached to the channel block and an example of assembling the assembly are shown.

[0020] Figure 8B An example of an assembly including a channel block and a sensing element holder attached to the channel block and an example of assembling the assembly are shown.

[0021] Figure 8C An example of an assembly including a channel block and a sensing element holder attached to the channel block and an example of assembling the assembly are shown.

[0022] Fig.9A is an exploded perspective view showing a cross section of a flange, a sensing element, and a sensing element holder.

[0023] Fig. 9B A state where the flange is pressed and fastened to the sensing element holder with screws is shown.

[0024] Fig. 10A is a cross-sectional view of the flange, sensing element, O-ring, and sensing element holder before they are assembled.

[0025] Fig. 10B It is a cross-sectional view showing a state in which a flange, a sensing element, and an O-ring are mounted on a sensing element holder but the flange has not yet been fastened to the sensing element holder by screws.

[0026] Fig. 10C This is a cross-sectional view of a state where a flange is pressed and fastened to a sensing element holder by screws.

[0027] Fig.11is a diagram showing the area between the prism of the sensing element and the sensing element holder to be sealed by the O-ring.

[0028] Fig. 12A An example of the region of the laminated film provided on the hypotenuse surface of the prism is shown.

[0029] Fig. 12B Shows Fig. 12A The sensing element in the embodiment is attached to the sensing element holder.

[0030] Fig. 12C A state in which a flange for pressing and fixing the sensing element is screwed to the sensing element holder is shown.

[0031] Fig.13A Another structural example of the sensing element is shown.

[0032] Fig. 13B Shown is a sensing element and an O-ring attached around the sides of the sensing element.

[0033] Fig.14A is a cross-sectional view showing a configuration example in which a sensing element including a truncated cone prism is fixed to serve as a part of a limiting wall.

[0034] Fig. 14B is another cross-sectional view showing a configuration example in which a sensing element including a truncated cone prism is fixed to serve as a part of a limiting wall.

[0035] Fig.15A The state of the O-ring when the O-ring, the sensing element, and the flange are placed on the sensing element holder in this order but the flange has not yet been fastened with screws is shown.

[0036] Fig. 15B The state where the flange is fastened to the sensing element holder with screws is shown.

[0037] Fig.16A is an exploded perspective view showing a cross section of components of an airtight structure in another embodiment.

[0038] Fig. 16B The state before the fixing is tightened with screws is shown.

[0039] Fig. 16C A state in which the fixing member is pressed and fastened to the limiting wall by means of screws is shown.

[0040] Fig.17A is a cross-sectional view of the screws, fixings, prism, transparent plate, O-ring and limiting wall before assembly.

[0041] Fig. 17B A state in which the fixing member is fastened to the limiting wall with screws is shown.

[0042] Fig.18A is a cross-sectional view showing a sealing structure using an O-ring.

[0043] Fig.18B is a cross-sectional view showing a sealing structure using an O-ring.

[0044] Fig.19 An example of the region of the laminated film provided on the hypotenuse surface of the prism is shown.

[0045] Fig. 20A The airtight structure in Embodiment 1 is schematically shown.

[0046] Fig. 20B The airtight structure in Embodiment 2 is schematically shown.

[0047] Fig. 20C The airtight structure in Embodiment 3 is schematically shown. DETAILED DESCRIPTION

[0048] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The elements in each figure have appropriate changes in size or proportion so that they can be well identified in the figures. The hatching in the figures is used to distinguish the elements and does not necessarily represent the cross section. It should be noted that the embodiments are merely examples for implementing the present invention and are not intended to limit the technical scope of the present invention.

[0049] The embodiments of this specification are about a gas sensor device as an example of an optical chemical sensor device. The gas sensor device in the embodiments detects a target substance by measuring a change in the optical characteristics of a sensing film caused by contact with the target substance.

[0050] A gas sensing element including a single-layer or multi-layer gas sensing film formed on a transparent substrate including a prism can be used in equipment for producing, refining or mixing gases. In order to use such a gas sensing element in these devices, it is required to prevent the gas to be tested (test object) at a pressure higher than the ambient pressure from leaking to the outside, or to prevent ambient air from entering the space including the gas to be tested at a pressure lower than the ambient pressure. In order to perform the test, the gas sensing film of the gas sensing element needs to be located in the gas to be tested. However, for safety reasons, the components to be energized, such as a light source and a photodetector, are arranged outside the atmosphere of the gas to be tested. Therefore, the light used for measurement needs to be transmitted through an airtight limiting wall.

[0051] One aspect of the present invention uses a sensing element including a prism as part of the limiting wall of the airtight space. This configuration enables the sensing film exposed to the test object to be illuminated by the measurement light from outside the airtight space while achieving compactness of the device.

[0052] Implementation Method 1

[0053] Figure 1 1 is a schematic diagram showing a hydrogen gas measurement method of a hydrogen gas sensor device in one embodiment of the present specification. As will be described later, a hydrogen gas sensing element in one embodiment of the present specification is fixed to cover an opening of a restriction wall for restricting hydrogen gas. The sensing element includes a sensing film formed on a transparent substrate. The transparent substrate includes a prism. The sensing element serves as a part of an airtight structure (restriction wall) that separates a hydrogen gas atmosphere from ambient air, and a gap between the transparent substrate and another part of the restriction wall is sealed by a sealing structure.

[0054] The hydrogen sensor device is an example of an optical chemical sensor device, and the target substance to be detected is hydrogen. The hydrogen sensor device can detect the concentration of hydrogen. Figure 1 The line with arrows in the figure indicates the optical path. The hydrogen sensor device is based on an oblique incidence optical system.

[0055] The hydrogen gas sensor device includes a light source 11, a polarization separation element (polarization separator) 13, a sensing element 14, a photodetector device 17, and a sensing controller 40. The illumination optical system includes the light source 11 and the polarization separation element 13. The sensing controller 40 controls the other components of the hydrogen gas sensor device, measures the intensity of light reflected from the sensing element 14, and calculates a measurement value based on the intensity of the reflected light.

[0056] The sensing element 14 includes a transparent plate 141 and a laminated film 140 provided on the transparent plate 141. The laminated film 140 is a laminated hydrogen sensing film, and includes a half mirror layer 142, an optical interference layer 143, and a hydrogen sensing layer 144 formed in sequence on the transparent plate 141. This configuration of the laminated film 140 is an example; the material to be used is appropriately selected, and the number of layers is appropriately determined from one or more layers.

[0057] The prism 146 is attached to the other side of the transparent plate 141 opposite to the laminate film 140 and optically coupled to the transparent plate 141 through optical coupling oil not shown. The prism 146 reduces incident light reflected from the lower side of the transparent plate 141 where the laminate film 140 is not provided and traveling toward the photodetector.

[0058] The surface of the hydrogen sensing layer 144 is in contact with the hydrogen gas 30 or the target substance. The hydrogen sensor device detects hydrogen by measuring the change in the optical characteristics of the sensing element 14 caused by the hydrogen gas 30. More specifically, the hydrogen sensor device detects the concentration of hydrogen by measuring the difference in reflectivity of the stacked film 140 to p-polarized light and s-polarized light corresponding to the concentration of hydrogen.

[0059] exist Figure 1In the configuration of the hydrogen sensor device, the stacked film 140 is obliquely irradiated with light through the prism 146 and the lower side of the stacked film 140 of the transparent plate 141 which is not provided for detecting the hydrogen 30. The photodetector device 17 detects the reflected p-polarized light 32p and the reflected s-polarized light 32s, and the sensing controller 40 determines the hydrogen concentration based on the difference between their intensities. The difference between their intensities can be expressed by a function using a difference or a ratio, which will be described later.

[0060] The stacked film 140 has such a structure that light reflected from the interface between the half mirror layer 142 and the transparent plate 141 interferes with light that has entered the stacked film 140 and is reflected from the hydrogen sensing layer 144. Figure 1 14. The light reflected from the interface between the half mirror layer 142 and the transparent plate 141 is not shown in the figure. The same applies to the other figures. The hydrogen sensor device causes the light emitted from the light source 11 to be obliquely incident on the surface of the stacked film of the sensing element 14. The oblique incidence optical system generally provides different reflectivity values ​​for p-polarized light and s-polarized light. In addition, a stacked film like the stacked film in the present embodiment applies different interference conditions to p-polarized light and s-polarized light.

[0061] The behavior of the p-polarized light and the s-polarized light reflected from the stacked film 140 providing the above conditions is reflected in the reflectivity of the stacked film 140 to the p-polarized light and the s-polarized light. What the photodetectors 171 and 172 actually detect is the intensity of the reflected p-polarized light 32p and the reflected s-polarized light 32s. Since the incident p-polarized light 31p and the incident s-polarized light 31s are obtained by separating the light from the single light source 11 with the polarization separation element 13, the ratio of their intensities is fixed. Therefore, the reflectivity of the p-polarized light and the s-polarized light in the form of a ratio can be obtained from the intensity ratio of the reflected p-polarized light 32p to the reflected s-polarized light 32s. Using the intensity ratio of the reflected p-polarized light 32p to the reflected s-polarized light 32s eliminates the influence of possible changes in the intensity of the light emitted from the light source.

[0062] Light emitted from the light source 11 reaches the laminated film 140 disposed on the transparent plate 141 through the prism 146. The light source 11 may be a monochromatic light source for emitting light of a single wavelength, such as a semiconductor laser, an LED, or a gas laser.

[0063] The polarization separation element 13 is disposed on an optical path between the light source 11 and the sensing element 14. The polarization separation element 13 separates the light from the light source 11 into p-polarized light 31p and s-polarized light 31s. The p-polarized light 31p and the s-polarized light 31s are incident on the sensing element 14. The p-polarized light 31p and the s-polarized light 31s travel along different optical paths and are incident on different points of the sensing element 14.

[0064] The p-polarized light 31p and the s-polarized light 31s separated by the polarization separation element 13 travel along different optical paths, pass through the prism 146, and reach the lower side of the transparent plate 141 where the stacked film 140 is not provided. They are incident on the lower side of the transparent plate 141 obliquely with respect to the stacking direction of the stacked film 140 (a direction perpendicular to the transparent plate 141). An example of the incident angle is 45°.

[0065] The p-polarized light 31p and the s-polarized light 31s having entered the transparent plate 141 are partially reflected from the interface between the transparent plate 141 and the half mirror layer 142. The remaining light passes through the half mirror layer 142 and the optical interference layer 143, is reflected from the hydrogen sensing layer 144, passes through the optical interference layer 143 and the half mirror layer 142 again in the opposite direction, and interferes with the above light reflected from the interface between the transparent plate 141 and the half mirror layer 142.

[0066] In this regard, the interference conditions of p-polarized light and s-polarized light are different. For the wavelength of light from the light source 11 to be used for sensing, the laminated film 140 is configured so that interference with p-polarized light or s-polarized light will produce a condition close to its resonance condition. The intensity of the reflected polarization component having a condition close to the resonance condition will take an extremely small value due to interference. On the other hand, the intensity of the reflected polarization component having a condition deviating from the resonance condition will take a relatively large value.

[0067] The p-polarized light 32p and the s-polarized light 32s reflected from the sensing element 14 travel along different optical paths. The reflected p-polarized light 32p and the reflected s-polarized light 32s are detected by the first photodetector 171 and the second photodetector 172, respectively. The first photodetector 171 and the second photodetector 172 are components of the photodetector device 17, and they are disposed at different positions. The first photodetector 171 is located on the optical path of the reflected p-polarized light 32p to detect the intensity of the reflected p-polarized light 32p, and the second photodetector 172 is located on the optical path of the reflected s-polarized light 32s to detect the intensity of the reflected s-polarized light 32s.

[0068] The sensing controller 40 controls the light emission of the light source 11, and also receives detection signals from the first photodetector 171 and the second photodetector 172. The sensing controller 40 receives signals representing the intensities of the reflected p-polarized light 32p and the reflected s-polarized light 32s from the first photodetector 171 and the second photodetector 172. The sensing controller 40 calculates the concentration of hydrogen gas based on the comparison results of these signals.

[0069] For example, the sensing controller 40 uses a predefined function (including a lookup table) to determine the hydrogen concentration based on the intensity of the reflected p-polarized light 32p and the reflected s-polarized light 32s. The function may include the ratio of the intensity of the p-polarized light to the intensity of the s-polarized light as a variable. If the ratio of the p-polarized component to the s-polarized component in the illumination system remains constant, the change in the intensity of the light emitted from the light source 11 can be ignored by using the ratio of the intensity of the reflected p-polarized light to the intensity of the reflected s-polarized light.

[0070] The sensing element 14 includes a stacked film 140, which is composed of a half mirror layer 142, an optical interference layer 143, and a hydrogen sensing layer 144 formed in sequence on a transparent plate 141. Figure 1 Each of these layers may be composed of a single layer or a plurality of layers. The hydrogen sensing layer 144 is a chemical sensing layer made of a material suitable for the target substance to be detected.

[0071] The optical properties of the hydrogen sensing layer 144, such as refractive index and absorption coefficient, change in response to contact with hydrogen. The hydrogen sensor device measures the change in intensity of reflected p-polarized light and s-polarized light caused by the change in the optical properties of the hydrogen sensing layer 144 to detect hydrogen.

[0072] The optical interference layer 143 is an intermediate layer having a structure that causes interference between light that enters the stacked film 140 and is reflected from the hydrogen sensing layer 144, among light that irradiates the stacked film 140, and light that is reflected from the interface between the transparent plate 141 and the half mirror layer 142. For example, the value of the sum of the product of the thickness and the refractive index of the half mirror layer 142 and the product of the thickness and the refractive index of the optical interference layer 143 is greater than about 1 / 4 of the wavelength of the irradiated light.

[0073] The half mirror layer 142 reflects a portion of the incident light and transmits another portion. The half mirror layer 142 has a thickness that allows light irradiating the stacked film 140 to enter the interior of the stacked film 140. For example, the half mirror layer 142 may have a thickness greater than 0 nm and not greater than 30 nm. The hydrogen sensing layer 144 has a thickness sufficient to reflect light entering the interior of the stacked film 140; for example, it may have a thickness of not less than 20 nm. A thicker hydrogen sensing layer 144 may reduce the influence of changes in the surface conditions of the sensing layer, thereby enabling more stable detection of target substances.

[0074] As a material for the hydrogen sensing layer 144, any material that changes its optical properties (e.g., refractive index or absorption coefficient) by reacting with hydrogen can be used. An example of such a material is palladium (Pd), whose optical properties change significantly in response to contact with hydrogen. A thin film containing palladium can be used as the hydrogen sensing layer 144. Such a hydrogen sensing layer 144 helps to provide a hydrogen sensor that is operable at room temperature and has high sensitivity, because palladium has the property of absorbing and releasing hydrogen at room temperature.

[0075] As for the material of the optical interference layer 143, common transparent oxides, transparent nitrides, and transparent fluorides, such as silicon dioxide (SiO2), zinc oxide (ZnO), magnesium oxide (MgO), titanium oxide (TiO2), aluminum nitride (AlN), silicon nitride (Si3N4), and magnesium fluoride (MgF2) can be listed. The optical interference layer 143 can be made of a dielectric having a high transmittance to the wavelength of the light emitted from the light source 11.

[0076] As the material of the half mirror layer 142, common metal materials including metals such as silver (Ag), aluminum (Al), gold (Au), copper (Cu), and tantalum (Ta), and alloys containing these metals can be cited. The material of the half mirror layer 142 can have high reflectivity for the wavelength of light emitted from the light source 11. The transparent plate 141 can be, for example, a glass substrate having a thickness of about 0.5 mm (500 μm).

[0077] As described above, the hydrogen gas sensor device irradiates the stacked film 140 with light from the lower side of the stacked film 140, and detects the p-polarized light and the s-polarized light reflected from the stacked film 140. The hydrogen gas sensor device detects hydrogen gas by detecting a change in the optical characteristics of the hydrogen gas sensing layer 144 caused by contact with the hydrogen gas 30 as an optical signal indicating a change in the intensity of the p-polarized light and the s-polarized light reflected from the stacked film 140.

[0078] When hydrogen contacts the hydrogen sensing layer 144, the optical properties of the hydrogen sensing layer 144 change, so that the interference conditions of the stacked film 140 change. The interference conditions of p-polarized light and s-polarized light change differently; in particular, the reflectivity of the polarization component having a condition close to the resonance condition changes significantly due to the change in the optical properties of the hydrogen sensing layer 144 caused by contact with hydrogen. Therefore, the intensity ratio of the reflected p-polarized light to the reflected s-polarized light changes significantly. It can be understood from this description that due to the optical interference occurring in the stacked film 140, the optical signal can be greatly enhanced, so that hydrogen can be detected with high sensitivity. The same applies to other target substances and stacked films including their chemical sensing layers.

[0079] Figure 2The following schematically shows an example of the configuration of a hydrogen gas sensor device in one embodiment of the present specification. Figure 1 The configuration example in . Figure 1 Like the configuration example in , this hydrogen sensor device is based on an oblique incident optical system; it obliquely illuminates the sensing element 14 through the prism 146 and the lower side of the transparent plate 141 where the stacked film 140 for sensing hydrogen is not provided to detect hydrogen. The sensing element 14 has Figure 1 The sensing element has the same structure as in the configuration example.

[0080] The illumination optical system includes a light source 11 and a polarizer 12. The polarizer 12 is disposed on the optical path of the incident light 31 between the light source 11 and the sensing element 14. The polarizer 12 transmits light linearly polarized in a specific direction and attenuates light polarized in other directions. The polarizer 12 can be pre-adjusted so that when the hydrogen concentration is within the measurement limit, the intensity difference between the reflected p-polarized light and the reflected s-polarized light will fall within a specific range. For example, the rotation angle of the polarizer 12 can be adjusted so that when hydrogen is not present, the intensities of the reflected p-polarized light and the reflected s-polarized light will be substantially equal. Such appropriate adjustment of the rotation angle of the polarizer 12 increases the accuracy of the measurement, but the polarizer 12 is optional.

[0081] In addition, a polarization separator 15 is provided on the optical path between the sensing element 14 and the photodetector device. Although for simplicity of illustration, Figure 2 No instructions shown Figure 1 The photodetector device 17 shown in the box, but with Figure 1 Like the photodetector device 17 in the configuration example, Figure 2 The photodetector device 17 in includes a first photodetector 171 and a second photodetector 172. The polarization separator 15 separates the p-polarized light 32p and the s-polarized light 32s from the light reflected from the sensing element 14. The p-polarized light 32p and the s-polarized light 32s from the polarization separator 15 travel along different optical paths.

[0082] The linearly polarized light 31 transmitted through the polarizer 12 passes through the prism 146 and is incident on the stacked film 140 of the sensing element 14 with an intensity ratio of the p-polarized component to the s-polarized component corresponding to the polarization angle. As described above, the linearly polarized light 31 is incident on the stacked film 140 at an angle inclined relative to the normal line of the stacked film 140. Figure 1 Unlike the above, the incident light is not separated into p-polarized light and s-polarized light, and the linearly polarized light 31 is incident on one point. Therefore, the influence of the characteristic difference within the plane of the stacked film 140 can be avoided.

[0083] The p-polarized light (component) and the s-polarized light (component) in the incident light have different interference conditions with the stacked film 140. In addition, the optical properties of the hydrogen sensing layer 144 change due to the hydrogen 30. Therefore, the reflectivity of the hydrogen sensing layer 144 and the interference conditions of the stacked film 140 for the p-polarized light and the s-polarized light change. Therefore, the intensity ratio of the p-polarized light to the s-polarized light in the light reflected from the stacked film 140 changes significantly.

[0084] The light reflected from the stacked film 140 enters the polarization separator 15 and is separated into p-polarized light 32p and s-polarized light 32s. These polarized lights propagate along different optical paths. The first photodetector 171 receives the p-polarized light 32p and outputs its intensity to the sensing controller 40. The second photodetector 172 receives the s-polarized light 32s and outputs its intensity to the sensing controller 40. This configuration of separating the light reflected from the sensing element 14 into p-polarized light and s-polarized light, detecting their intensities, and using their ratio can eliminate the influence of intensity variations of the light from the light source.

[0085] Figure 3A and Figure 3B 146 is a diagram showing the structure of the prism 146. The prism 146 is a right angle prism having a triangular prism shape. The structure of the prism is not limited to Figure 3A and Figure 3B In addition, the angle between the incident light on the prism 146 and the reflected light coming out of the prism 146 is not limited to 90°.

[0086] exist Figure 3A and Figure 3B In the structural example of the prism 146 in FIG. 1 , the prism 146 has a hypotenuse face 181 and two right-angled faces 182 and 183 sandwiching the hypotenuse face 181. The hypotenuse face 181 continues to the two right-angled faces 182 and 183. The angle between the right-angled faces 182 and 183 is a right angle, and the angle between the right-angled face 182 and the hypotenuse face 181 and the angle between the right-angled face 183 and the hypotenuse face 181 are 45°. The transparent plate 141 with the laminated film 140 is placed on the hypotenuse face. The other two faces defined by the hypotenuse face 181 and the right-angled faces 182, 183 are the top base and the bottom base of the triangular prism.

[0087] Figure 4 2 is a cross-sectional view schematically showing a configuration example of a sensing element 250 in one embodiment of the present specification. The sensing element 250 includes a laminated film 260 for sensing hydrogen on a transparent plate 251 made of glass. The laminated film 260 is composed of a seed layer 252, a half mirror layer 253, an optical interference layer 254, and a hydrogen sensing layer 255. The seed layer 252, the half mirror layer 253, the optical interference layer 254, and the hydrogen sensing layer 255 are formed on the transparent plate 251 in this order.

[0088] The half mirror layer 253 is a 14 nm thick Ag film. The optical interference layer 254 is a laminated film consisting of a 30 nm thick ZnO film and a 143 nm thick Al2O3 film. The hydrogen sensing layer 255 is a 100 nm thick PdCuSi alloy film. The seed layer 252 is a 30 nm thick ZnO film. The seed layer 252 maintains adhesion to the transparent plate 251.

[0089] The prism 256 is disposed on the lower side of the transparent plate 251 where the laminate film 260 is not disposed, and the prism 256 is optically coupled to the transparent plate 251 using the optical coupling oil 257. The prism 256 reduces the influence of light reflected from the lower side of the transparent plate 251. The optical coupling oil 257 reduces the reflection of light from the interface between the transparent plate 251 and the prism 256.

[0090] Figure 5 2 is a cross-sectional view schematically showing a configuration example of a sensing element 270 in one embodiment of the present specification. The sensing element 270 has a structure such that the transparent plate 251 and the optical coupling oil 257 are excluded from the sensing element 270. Figure 4 250. This example is produced by directly forming a laminated film on the hypotenuse surface of the prism 256 without using a thin glass plate. The absence of a thin glass plate in the area that receives pressure for fixing the sensing element 270 increases the mechanical strength of the sensing element. In addition, the absence of optical coupling oil eliminates contamination of the gas to be tested. On the other hand, the sensing element 250 produced by forming a layer on the transparent plate 251 can be manufactured more easily and efficiently than the sensing element 270 produced by forming a layer on the prism 256 because it is easy to hold the substrate during layer formation.

[0091] In the gas sensor device of the embodiment of the present specification to be described below, the sensing element 14 may have a reference Figure 4 or Figure 5 The configuration described or another configuration. For example, the seed layer can be excluded. The hydrogen sensing layer 255 can have a protective layer to protect the surface of the hydrogen sensing layer 255 and / or accelerate the reaction by utilizing its catalytic effect. Each layer can be composed of multiple layers instead of a single layer. The prism 256 can have an anti-reflection film on its right-angled edge surface.

[0092] Figure 6 An example of configuration and use of a hydrogen gas sensor device in one embodiment of the present specification is shown. Figure 6The hydrogen sensor device is depicted as being inserted in the middle of a tube 315 for transmitting a gas to be tested to measure the hydrogen concentration in the gas flowing through the gas channel 310 of the hydrogen sensor device. The gas to be tested is a gas that contains or can contain hydrogen, and the space in the gas channel 310 can be pressurized or depressurized depending on the application. In other words, the pressure in the gas channel 310 can be equal to or higher than or lower than the ambient pressure. The gas that contains or can contain hydrogen flows through the gas channel 310. The hydrogen sensor device has a reference Figure 2 The optical system in the configuration example described, but may be omitted Figure 2 Some of the configuration examples in the Figure 2 Some components not shown.

[0093] The gas channel 310 is defined by a limiting wall formed by a channel block 320 and a sensing element holder 350 to which the sensing element 14 is attached; the limiting wall separates the space of the gas channel 310 and the gas flowing therethrough from the outside. The two components forming the limiting wall, namely the channel block 320 and the sensing element holder 350, are arranged in a Figure 6 The channel block 320 and the sensing element holder 350 may be made of metal or resin.

[0094] The sensing element holder 350 has a plate-like shape having a hollow portion, and the sensing element 14 is embedded in the hollow portion. The sensing element 14 is pressed and fixed to the sensing element holder 350 by the flange 360. The flange 360 ​​is fastened to the sensing element holder 350 by screws, for example. The screws in this specification include bolts. The laminated film 140 of the sensing element 14 is exposed in the gas channel 310 through the hole in the flange 360. The hole is a through hole. The light from the light source 11 irradiates the sensing element 14 through the hole 351 in the sensing element holder 350. The light reflected from the sensing element 14 enters the polarization separator 15 through another hole 352 in the sensing element holder 350.

[0095] The sensing element holder 350 is fastened to the channel block 320 with screws, for example. A flange 360 ​​is fastened to the surface of the sensing element holder 350 that faces the channel block 320. An O-ring 370 is interposed between the sensing element holder 350 and the channel block 320. The O-ring 370 surrounds the flange 360. The O-ring 370 seals the gap between the channel block 320 and the sensing element holder 350 to prevent gas from leaking from the gas channel 310 or to prevent ambient air from flowing into the gas channel 310. All O-rings described below are examples of elastic sealing members.

[0096] FIG. 7A to FIG. 7D An example of an airtight structural assembly utilizing the sensing element 14 in the hydrogen sensor device and an example of assembling the airtight structural assembly are shown. Fig. 7A A structural example of the sensing element holder 350 is shown. Fig. 7A 3 is a diagram when the sensing element holder 350 is viewed from the side where the channel block 320 is located.

[0097] The sensing element holder 350 has a hollow portion on the face facing the channel block 320. The sensing element 14 is embedded in the hollow portion 356. Holes 351 and 352, which are part of the optical path of the light for measurement, open in the inner surface of the hollow portion 356. The hollow portion 356 continues to the outside of the channel through the holes 351 and 352. The faces with the openings of the holes 351 and 352 are parallel to the right-angled faces 182 and 183 of the prism 146, and are inclined to the portion of the limiting wall facing the holes 351 and 352. The other two substantially triangular inner faces between the faces with the openings are perpendicular to the portion of the limiting wall to conform to the shape of the other faces of the prism 146.

[0098] The sensing element 14 is placed in the hollow portion 356 so that the right-angled sides 182 and 183 of the sensing element 14 cover the holes 351 and 352, respectively. The inner surface of the hollow portion 356 has recessed areas (steps) 353 and 354 around the openings of the holes 351 and 352. The recessed areas 353 and 354 are sealing areas to be sealed by O-rings. As described above, the hollow portion 356 includes a space shaped like a triangular prism for accommodating the sensing element 14 having a prism and an annular space for accommodating an O-ring. The holes 351 and 352, the hollow portion 356, and the sealing areas 353 and 354 can be formed by machining a thick metal plate.

[0099] Figure 7B The sensing element holder 350 and the O-rings 371 and 372 placed in the hollow portion 356 are shown. The O-rings 371 and 372 are placed on the sealing area 353 around the hole 351 and the sealing area 354 around the hole 352, respectively. For example, the inner diameter (diameter of the center hole) of the annular O-rings 371 and 372 is equal to or greater than the diameter of the holes 351 and 352, the outer diameter is equal to or less than the outer diameter of the sealing areas 353 and 354, and the cross-sectional diameter (thickness) is greater than the depth of the sealing areas 353 and 354. The difference between the cross-sectional diameter and the depth of the sealing areas 353 and 354 is within the range where the compression (extrusion) amount of the O-rings 371 and 372 can provide effective sealing characteristics. The cross section of the elastic ring used for sealing does not need to be circular like a normal O-ring, but can be elliptical or quadrilateral. The same applies to other embodiments.

[0100] Figure 7C1 shows a configuration example of an assembly of a sensing element holder 350 and a sensing element 14 attached to the sensing element holder 350. The sensing element 14 is embedded in a hollow portion 356 formed in one main surface of the plate-shaped sensing element holder 350. The main surface will face the channel block 320 and the gas channel 310. The right-angled side surfaces 182 and 183 (these reference numerals are in Figure 7C 350) are opposite to the inner surface of the hollow portion 356, and a portion of them is exposed in the holes 351 and 352. The right-angled side faces 182 and 183 are in contact with the O-rings 371 and 372, respectively. The beveled side face 181 is exposed from the surface of the sensing element holder 350 facing the channel block 320. The area of ​​the beveled side face 181 exposed from the hollow portion 356 is exposed to the hydrogen gas in the gas channel 310.

[0101] Fig.7D A configuration example of an assembly including a flange 360 ​​in addition to the sensing element 14 and the sensing element holder 350 is shown. The flange 360 ​​is an annular plate having a circular outer end and a circular inner end, and has a hole 363 at the center. The flange 360 ​​is fastened to the sensing element holder 350 by a plurality of screws 362. The screws 362 extend through the mounting holes of the flange 360 ​​to be inserted into the screw holes of the sensing element holder 350. The screw holes of the sensing element holder 350 are not through holes. 7A to 7C The screw holes of the sensing element holder 350 are not shown to avoid complexity of the figure. Fig.7D In the embodiment, one of the screws has reference numeral 362 as an example. The flange 360 ​​covers a portion of the bevel surface 181, and the laminated membrane 140 ( Fig.7D The entire or partial area of ​​​​the device (not shown) is exposed from the hole 363.

[0102] The flange 360 ​​is a fixing member for pressing and fixing the sensing element 14 to the sensing element holder 350. The hollow portion 356 is formed so that if the sensing element 14 is embedded in the hollow portion 356 without the O-rings 371 and 372, the hypotenuse surface 181 of the prism 146 will be substantially flush with the sensing element holder 350. When the sensing element 14 is pressed by the flange 360, the O-rings 371 and 372 in contact with the right-angled surfaces 182 and 183 and the sealing areas 353 and 354 of the sensing element holder 350 are compressed. When the sensing element 14 is accommodated at a predetermined position in the hollow portion 356, the O-rings 371 and 372 appropriately seal the gap between the right-angled surface 182 and the sealing area 353 and the gap between the right-angled surface 183 and the sealing area 354 by their compression amount.

[0103] An elastic sealing component such as an O-ring seals the gap between the sealing areas by being compressed by another component so that its cross section becomes flat. The expression "flattened" means that the cross section of the elastic sealing component is elastically deformed due to pressure, so that the dimension in the pressure direction is reduced and the dimension in other directions is increased. The fixing member presses the sensing element so that the elastic sealing component is compressed and elastically deformed to fix the sensing element.

[0104] Fig. 8A , Figure 8B and Figure 8C An example of an assembly including a channel block 320 and a sensing element holder 350 attached to the channel block 320 and an example of assembling the assembly are shown. Fig. 8A shows a configuration example of a channel block 320, Figure 8B An example of the configuration of the channel block 320 and the O-ring 370 placed on the channel block 320 is shown.

[0105] The channel block 320 has a hollow portion 323. The bottom of the hollow portion 323 has a hole as a part of the gas channel 310. Fig.7D The flange 360 ​​is described as being embedded in the hollow portion 323. The channel block 320 has a recessed area (step) 325 around the opening of the hollow portion 323. An O-ring 370 is placed on the recessed area 325 around the opening of the hollow portion 323. The recessed area 325 is a sealing area; the O-ring 370 is placed on the sealing area 325. For example, the inner diameter of the annular O-ring 370 is equal to or greater than the inner diameter of the sealing area 325, the outer diameter is equal to or less than the outer diameter of the sealing area 325, and the cross-sectional diameter (thickness) is greater than the depth of the sealing area 325. The difference between the cross-sectional diameter and the depth of the sealing area 325 is within the range in which the compression amount of the O-ring 370 can provide effective sealing characteristics. The cross section of the elastic ring used for sealing does not need to be circular like a normal O-ring, but can be elliptical or quadrilateral.

[0106] Figure 8C A configuration example of an assembly including a channel block 320 and a sensing element holder 350 fixed to the channel block 320 is shown. Fig.7D The assembly including the sensing element holder 350, the sensing element 14, and the flange 360 ​​is mounted on the channel block 320 by inserting the flange 360 ​​into the hollow portion 323. The sensing element holder 350 is fixed to the channel block 320 by a plurality of screws 375. The screws 375 extend through the mounting holes of the sensing element holder 350 to be inserted into the screw holes of the channel block 320. The screw holes are not through holes for the gas passage, and the screw holes do not penetrate the gas passage. Figure 8C In the drawings, as an example, one of the screws has reference numeral 375 .

[0107] The inner diameter of the O-ring 370 is larger than the outer diameter of the flange 360; the flange 360 ​​is placed in the hole of the O-ring 370. The O-ring 370 is compressed by the sensing element holder 350 to properly seal the gap between the sensing element holder 350 and the channel block 320, thereby obtaining the same Figure 6 The structure corresponds to the structure shown in the cross-sectional view.

[0108] As mentioned above, FIG. 8A to FIG. 8C The flange 360 ​​not shown in the figure is located in the hollow portion 323 of the channel block 320, and at least a portion of the laminated film 140 on the bevel surface 181 of the sensing element 14 is exposed to the gas channel 310 through the hole 363 of the flange 360 ​​(see Fig.7D ). Light from the light source 11 enters the hole 351 , and light reflected from the sensing element 14 is emitted through the hole 352 .

[0109] Next, fixing of the sensing element 14 by the flange 360 ​​and the sensing element holder 350 will be described in more detail. Fig.9A 3 is an exploded perspective view showing a cross section of the flange 360, the sensing element 14, and the sensing element holder 350. Fig.9A The upper side of the sensor 14 is provided with hydrogen as a target substance, and the ambient air is on the lower side. The light from the light source 11 travels through the hole 351 and enters the sensing element 14. The light reflected from the sensing element 14 is emitted through the hole 352.

[0110] An O-ring 371 is placed on a sealing area 353 provided in the hollow portion 356 of the sensing element holder 350. An O-ring 372 is placed on a sealing area 354 provided in the hollow portion 356 of the sensing element holder 350. The inner end of the sealing area 353 defines the opening of the hole 351, and the inner end of the sealing area 354 defines the opening of the hole 352.

[0111] The sensing element 14 including the prism 146 is placed in the hollow portion 356. The right-angled surface 182 faces the O-ring 371 and the hole 351, and contacts the O-ring 371. The right-angled surface 183 faces the O-ring 372 and the hole 352, and contacts the O-ring 372. The hypotenuse surface 181 is located in the opening of the hollow portion 356 (on the opposite side of the bottom of the hollow portion 356). The flange 360 ​​is attached to the sensing element holder 350 to contact a portion of the hypotenuse surface 181.

[0112] When the O-rings 371 and 372, the sensing element 14 and the flange 360 ​​are only placed at predetermined positions on the sensing element holder 350, the bevel surface 181 of the sensing element 14 is located at a position higher than the sensing element holder 350, and the O-rings 372 and 371 have not yet been elastically deformed. Fig.7DFastening the flange 360 ​​to the sensing element holder 350 with screws 362 as shown compresses and elastically deforms the O-rings 371 and 372 between the sensing element 14 and the sensing element holder 350, thereby sealing the gap therebetween.

[0113] Fig. 9B The screw 361 ( Fig. 9B The state where the flange 360 ​​is pressed and fastened to the sensing element holder 350 (not shown in the figure). The sensing element 14 is pressed by the flange 360 ​​and descends to the inner surface (the surface oriented toward the test object) of the hollow portion 356 of the sensing element holder 350. The right-angled side surfaces 182 and 183 are in contact with the top surface of the step provided around the O-rings 371 and 372. In this state, the O-rings 371 and 372 are compressed by an appropriate amount.

[0114] Fig. 10A is a cross-sectional view of the flange 360, the sensing element 14, the O-rings 371 and 372, and the sensing element holder 350 before they are assembled, and corresponds to Fig.9A . Fig. 10A The upper area is the area where hydrogen is to be supplied, and the lower area is the area where the optical system is set.

[0115] Fig. 10B The O-rings 371 and 372, the sensing element 14, and the flange 360 ​​are mounted on the sensing element holder 350 but not yet screwed with the screws 361 ( Fig. 10B 350). The sensing element 14 is placed on the O-rings 371 and 372. The right-angled surfaces 182 and 183 are in contact with the O-rings 371 and 372, respectively. The O-rings 371 and 372 are not compressed; the beveled surface 181 of the sensing element 14 is located higher than the top surface of the sensing element holder 350. The flange 360 ​​is placed on the beveled surface 181 in a manner that a portion of the beveled surface 181 is exposed through the hole 363 of the flange 360.

[0116] Fig. 10C Use screw 361( Fig. 10C (not shown) is a cross-sectional view of a state in which the flange 360 ​​is pressed and fastened to the sensing element holder 350, and corresponds to Fig. 9BThe sensing element 14 is pressed by the flange 360 ​​and lowered to the inner surface (the surface oriented toward the test object) of the hollow portion 356 of the sensing element holder 350. The right-angled side surfaces 182 and 183 are in contact with the top surface of the step provided around the O-rings 371 and 372. In this state, the O-rings 371 and 372 are compressed between the right-angled side surfaces 182, 183 and the inner surface of the hollow portion 356 to seal the gap between the right-angled side surfaces 182, 183 and the inner surface of the hollow portion 356.

[0117] Fig.11 is a diagram showing a region between the prism 146 of the sensing element 14 and the sensing element holder 350 to be sealed by O-rings 371 and 372 . Fig.11 A state after the flange 360 ​​is fastened to the sensing element holder 350 is shown.

[0118] exist Fig.11 , the beveled surface 181 of the sensing element 14 is pushed vertically downward by the flange 360. The sealing area of ​​the sensing element 14 is a part of the right-angled surfaces 182 and 183 inclined at 45° relative to the beveled surface 181; the components of the thrust in two directions compress the O-rings 371 and 372. Therefore, the sealing areas of the right-angled surfaces 182 and 183, and the sealing areas 353 and 354 of the sensing element holder 350 are sealed together.

[0119] In common usage of O-rings, pressure is applied in a direction to compress the O-rings; however, this configuration example applies force in a direction different from the direction to compress the O-rings 371 and 372 to compress the O-rings 371 and 372 at the same time using its component force, thereby achieving sealing.

[0120] Next, the area of ​​the laminated film 140 on the hypotenuse surface 181 of the prism 146 is described. If the laminated film 140 is formed on the right angle prism without any consideration, the flange 360 ​​contacts the laminated film 140 when the sensing element 14 is fixed. If the laminated film 140 contacts the flange 360 ​​in a certain area, the film may be damaged in the contact area. Damage only at a single point may spread from there to affect the entire laminated film 140. One embodiment of the present specification forms the laminated film 140 to cover the area that helps measure hydrogen while avoiding the area contacted by the flange 360.

[0121] Fig. 12A An example of the region of the laminate film 140 disposed on the hypotenuse surface 181 of the prism 146 is shown. Fig. 12AThe laminate film 140 has a circular shape, but the shape of the laminate film 140 is not limited to a specific shape. The laminate film 140 can be formed directly on the hypotenuse surface 181 of the prism 146. Alternatively, the laminate film 140 can be formed on a glass plate, and the other side of the glass plate can be coupled to the hypotenuse surface 181 of the prism 146 with optical coupling oil. The laminate film 140 can generally be formed by sputtering. In order to form the laminate film 140 on a portion of the hypotenuse surface 181 of the prism 146, while holding the prism 146 for film formation, a metal mask having an opening in a region corresponding to a portion of the hypotenuse surface 181 of the prism 146 where the laminate film is to be formed can be used.

[0122] Fig. 12B Shows Fig. 12A The sensing element 14 in FIG. 1 is attached to the sensing element holder 350 . Fig. 12C A state in which the flange 360 ​​for pressing and fixing the sensing element 14 is screwed to the sensing element holder 350 is shown.

[0123] like Fig. 12C As shown, the entire laminated film 140 is located in the central hole 363 of the flange 360. Since the laminated film 140 does not contact the flange 360, the laminated film 140 will not be damaged by the flange 360, thereby preventing the laminated film 140 from peeling off from the damaged point.

[0124] Implementation Method 2

[0125] Another structural example of the prism is described. Fig.13A 4 shows a structural example of the sensing element 44. The sensing element 44 has a shape such that a right-angled surface is formed on a truncated cone. Specifically, the hypotenuse surface 481 is one of the bases of the truncated cone, and the right-angled surfaces 482 and 483 are two flat inclined surfaces formed on the side of the truncated cone at an angle of 45° with respect to the hypotenuse surface 481 and perpendicular to each other. A laminated film for measuring hydrogen is provided on the hypotenuse surface 481. Fig.13A The prism 446 of the sensing element 44 in FIG. 4 is a right-angle prism.

[0126] Fig. 13B The sensing element 44 and an O-ring 470 attached around the side of the sensing element 44 are shown. The O-ring 470 seals the gap between the side of the truncated cone and the limiting wall. The O-ring 470 has a torus shape, and its cross section is circular. The inner diameter of the O-ring 470 is smaller than the diameter of the bevel surface 481. Fig. 13BIn the configuration example of , the O-ring 470 is disposed outside the right-angled surfaces 482, 483 and between the hypotenuse surface 481 and the right-angled surfaces 482, 483. The cross section of the O-ring 470 does not need to be circular. The shape of the O-ring 470 is consistent with the outer end of the side of the prism 446 of the sensing element 44. Therefore, if the outer end of the side of the sensing element 44 is elliptical, the O-ring is also an elliptical ring.

[0127] Fig.14A and Fig. 14B : is a cross-sectional view showing a configuration example in which a sensing element 44 including a truncated cone prism is fixed to serve as a part of a limiting wall. Fig.14A This is a state before the sensing element 44 and the flange 560 are mounted on the sensing element holder 550. The sensing element 44 is pressed and fixed between the flange 560 and the sensing element holder 550 having a plate-like shape. The sensing element holder 550 corresponds to the sensing element holder 350 described above.

[0128] The flange 560 is fastened to the sensing element holder 550 by a plurality of screws 575. The screws 575 extend through holes in the flange 560 to be inserted into screw holes in the sensing element holder 550. These screw holes are not through holes. Fig.14A and Fig. 14B In the embodiment, as an example, one of the plurality of screws has reference numeral 575. Flange 560 may have a disc-like shape with a hole 563 in the center similar to flange 360. Fig.14A The upper side of the sensor 44 is provided with hydrogen as the target substance, and the ambient air is on the lower side. The light from the light source 11 travels through the hole 551 and enters the sensing element 44. The light reflected from the sensing element 44 is emitted through the hole 552.

[0129] The O-ring 470 is placed on the sealing area 553 located on the step provided inside the tapered hole 556 of the sensing element holder 550. The sealing area 553 faces the flange 560 and is annularly formed on the inner side surface of the hole 556. The O-ring 470 is placed on the sealing area 553. The inner end of the sealing area 553 defines the opening of the deeper space of the hole 556 for accommodating the right-angle side surfaces 482 and 483.

[0130] exist Fig.14A and Fig. 14B In the configuration example of , the hole 556 has two spaces. A space of shallower depth ( Fig.14A The upper space in the middle) has a cylindrical shape with uniform width. The deeper space ( Fig.14AThe lower space in the prism 540 has a shape similar to a truncated cone, and its width gradually decreases from the area closer to the flange 560. The inner surface of the hole 556 defining the truncated cone space is conical and is substantially the same as the conical surface of the side surface of the truncated cone prism 446.

[0131] The sensing element 44 including the prism 446 is placed in the hole 556. The right-angled surface 482 faces the hole 551. The right-angled surface 483 faces the hole 552. The hypotenuse surface 481 is located on the opposite side of the holes 551 and 552. The flange 560 is mounted on the sensing element holder 560 in such a manner that the flange 560 contacts a portion of the hypotenuse surface 481. The laminated film of the sensing element 44 is exposed from the hole 563 of the flange 560.

[0132] When the O-ring 470 , the sensing element 44 , and the flange 560 are merely placed at a predetermined position on the sensing element holder 550 , the beveled surface 481 of the sensing element 44 is located higher than the sensing element holder 550 , and the O-ring 470 is not yet compressed.

[0133] Fig. 14B FIG. 5 shows a state where the flange 560 is fastened to the sensing element holder 550 by screws 575. The side of the prism 446 and the deeper ( Fig.14A The O-ring 470 is interposed between the side of the prism 446 and the inner surface of the hole 556 of the sensing element holder 550, surrounding the opening. Since the flange 560 is fastened to the sensing element holder 550 with the screw 575, the O-ring 470 is compressed between the side of the prism 446 and the inner surface of the hole 556 of the sensing element holder 550 to seal the gap therebetween.

[0134] Fig.15A The state of the O-ring 470 is shown when the O-ring 470, the sensing element 44, and the flange 560 are placed on the sensing element holder 550 in this order but the flange 560 has not yet been fastened with the screw 575. The O-ring 470 is surrounded by the faces 553 and 554 defining the hole 556 of the sensing element holder 550, and a portion 485 of the side surface of the prism 446. As described above, the O-ring 470 is placed on the sealing area 553, and then the prism 446 is inserted into the hole 556. The flange 560 is placed on the prism 446. The O-ring 470 has not yet been compressed.

[0135] Fig. 15B The state in which the flange 560 is fastened to the sensing element holder 550 by the screw 575 is shown. The O-ring 470 is in contact with the sealing areas 553, 554 and 485 and is compressed by being pressed against these areas. In this state, the O-ring 470 functions as a seal.

[0136] Implementation 3

[0137] Another embodiment of the airtight structure using a sensing element including a prism is described. The prism has the same structure as the prism described in Embodiment 1. Fig.16A 6 is an exploded perspective view showing a cross section of the components of the airtight structure in this embodiment. The airtight structure includes a fixing member 660, a prism 146 and a transparent plate 141 of the sensing element 14, a limiting wall 650, and an O-ring 670. Fig.16A The lower side of the prism is provided with hydrogen as a target substance, and the ambient air is on the upper side. Although the sensing element 14 in the following description includes the transparent plate 141, the transparent plate 141 is optional. In another example, the laminated film 140 may be directly formed on the hypotenuse surface of the prism.

[0138] Fig.16A shows half of the airtight structure. Fig.16A Another structure having the same structure as in the embodiment is symmetrically located on the opposite side with respect to the cross section as the symmetry plane. That is, the prism 146 can be fixed to the limiting wall 650 by a single fixing member 660. The fixing member 660 may be two or more separate fixing members.

[0139] The O-ring 670 is placed on the sealing area 652, which is located on a step provided in the hole 656 of the limiting wall 650. The height of the step between the sealing area 652 and the supporting area 654 is smaller than the cross-sectional diameter of the O-ring 670. The difference between the cross-sectional diameter and the step height is within a range in which the amount of compression of the O-ring 670 can provide effective sealing characteristics.

[0140] The sensing element 14 including the prism 146 and the transparent plate 141 is placed on the O-ring 670 in the hole 656 of the limiting wall 650. The transparent plate 141 is in contact with the O-ring 670. The right-angled side faces 182 and 183 are oriented toward the opposite side of the sealing area 652 of the limiting wall 650 or toward the ambient air. A part of the hole 656 becomes a part of the gas passage.

[0141] The fixing member 660 is placed on the prism 146 and the limiting wall 650 in such a manner that the fixing member 660 covers a portion of the prism 146, in particular, a portion of the right-angled side faces 182 and 183. The fixing member 660 has a shape that matches the corner between the right-angled side faces 182 and 183 of the prism 146 in a portion opposite to the prism 146, and the surface of the portion contacts the portion of the right-angled side faces 182 and 183. In addition, the screw 675 extends through the hole in the fixing member 660 to be inserted into the screw hole of the limiting wall 650.

[0142] Fig. 16B6. The state before the fixing member 660 is fastened with the screw 675 is shown. When the O-ring 670, the sensing element 14, and the fixing member 660 are merely placed at a predetermined position on the limiting wall 650, the O-ring 670 is not yet compressed. Fastening the fixing member 660 to the limiting wall 650 with the screw 675 causes the O-ring 670 to be compressed between the sensing element 14 and the limiting wall 650 to seal the gap therebetween.

[0143] Fig. 16C FIG. 6 shows a state where the fixing member 660 is pressed and fastened to the limiting wall 650 by the screw 675. The transparent substrate including the prism 146 and the transparent plate 141 is fixed to the Fig. 16C The transparent substrate including the prism 146 and the transparent plate 141 is pressed against the O-ring 670 by the fixing member 660. In this state, the O-ring 670 is compressed between the transparent plate 141 of the transparent substrate and the sealing area 652. When the transparent plate 141 is in contact with the support area 654 and fixed in a predetermined position, the O-ring 670 is compressed by an appropriate amount so that the gap between the inner surface of the hole 656 and the sensing element 14 is sealed.

[0144] The optical paths of the incident light 31 on the right-angled side surface 182 and the reflected light 32 emitted from the right-angled side surface 183 pass through the space between the fixing member 660 and the limiting wall 650. As described in this specification, the airtight structure is designed so that the optical path of the light used for measurement will not be blocked by the components. Fig. 16C In the embodiment, the space below the transparent plate 141 of the hole 656 is an airtight space to provide hydrogen. The airtightness is maintained by the O-ring 670. The laminated film 140 on the transparent plate 141 is exposed to hydrogen in the area surrounded by the O-ring 670 in the hole 656.

[0145] Fig.17A is a cross-sectional view of the screw 675, the fixing member 660, the prism 146, the transparent plate 141, the O-ring 670, and the limiting wall 650 before assembly. Fig.17A The lower area is the area where hydrogen is to be supplied, and the upper area is the area where the optical system is set.

[0146] The hole 656 of the limiting wall 650 includes Fig.17A The topmost space or the space closest to the fixing member 660 accommodates the sensing element 14 (a part thereof) including the prism 146 and the transparent plate 141. Fig.16A and 17A As shown, the space for accommodating the sensing element 14 has a substantially rectangular parallelepiped shape.

[0147] The second space accommodates the O-ring 670 and has a shape similar to a rounded rectangular column. In this example, the space has a rounded rectangular cross section to provide a larger opening so that the quadrilateral membrane surface of the sensing element can contact the test object as much as possible, and the O-ring 670 is arranged along its inner wall. However, the cross section of the space can be circular or elliptical. When viewed from the side where the fixture 660 is to be placed, the space is located inside the space for accommodating the sensing element 14. The lowest space has the shape of a rounded rectangular column and is part of the gas channel 310. The opening of the space has a shape similar to the shape of the opening of the space for accommodating the O-ring 670. When viewed from the side where the fixture 660 is to be placed, the space is located inside the space for accommodating the O-ring 670. The shape of the space included in the hole 656 is not limited to the above shape.

[0148] An O-ring 670 is placed on the sealing area 652. In addition to the sealing area 652, the inner face of the hole 656 is also provided with a support area 654. As will be described later, the support area 654 supports the sensing element 14. These areas 652 and 654 are oriented toward the transparent plate 141 or the prism 146. Fig.17A 654, the regions 652 and 654 are oriented upward. The sealing region 652 is the top surface of the lower step formed on the inner surface of the hole 656, and the support region 654 is the top surface of the upper step. When viewed from the side where the prism is placed, the two regions 652 and 654 have an annular shape, and the inner diameter of the support region 654 may be equal to or greater than the outer diameter of the sealing region 652.

[0149] After the O-ring 670 is placed on the sealing area 652, the sensing element 14 including the transparent plate 141 and the prism 146 is placed on the O-ring 670. The main surface of the transparent plate 141 faces the O-ring 670 and contacts the O-ring. Fig.17A and Fig. 17B When the assembly is viewed in the vertical direction (pressing direction) in FIG. 1 , the outer end of the O-ring 670 is located inside the main surface of the transparent plate 141. The main surface of the transparent plate 141 is away from the support area 654. The laminate film 140 is provided on the surface of the transparent plate 141 facing the O-ring 670.

[0150] Subsequently, the fixing member 660 is placed on the prism 146 and the limiting wall 650 in such a manner that the fixing member 660 covers a portion of the right-angled side faces 182 and 183 of the prism 146. The screw 675 is inserted into the mounting hole of the fixing member 660 to be inserted into the screw hole of the limiting wall 650. The screw 675 is tightened so that the transparent substrate including the prism 146 and the transparent plate 141 is downwardly inserted into the hole 656 to compress the O-ring 670.

[0151] Fig. 17BThe state where the fixing member 660 is fastened to the limiting wall 650 by the screw 675 is shown. The sensing element 14 including the prism 146 and the transparent plate 141 is pressed against the O-ring 670 and the support area 654 by the fixing member 660. The sensing element 14 and the O-ring 670 cover the opening of the hole 656 of the limiting wall 650.

[0152] The sensing element 14 is pressed and fixed between the fixing member 660 and the limiting wall 650. In this state, the transparent plate 141 contacts the supporting area 654. The O-ring 670 is compressed between the sealing area 652 and the transparent plate 141 to seal the gap between the transparent plate 141 and the sealing area 652.

[0153] Fig.18A and Fig.18B is a cross-sectional view showing a sealing structure using an O-ring 670 . Fig.18A The state in corresponds to Fig. 16B status in . Fig.18B The state in corresponds to Fig. 16C Specifically, in Fig.18A , the O-ring 670 and the sensing element 14 are placed in the hole 656 of the limiting wall 650, but the sensing element 14 is not pressed by the fixing member 660. The transparent plate 141 is on and in contact with the O-ring 670. The transparent plate 141 is away from the supporting area 654.

[0154] An O-ring 670 is placed over the sealing area 652. Fig.18A In the example of , the O-ring 670 has a circular cross section and has a cross-sectional diameter D. The cross-sectional diameter D is greater than the step height H between the two regions 652 and 654. The difference between the cross-sectional diameter D and the step height H is the amount of extrusion of the O-ring 670. The transparent plate 141 is inserted into the hole 656 in such a manner that the end surface of the transparent plate 141 slides along the wall 657 which is a part of the inner surface of the hole 656. The wall 657 serves as a guide to bring the transparent substrate including the prism 146 into position.

[0155] Fig.18B The transparent plate 141 and the O-ring 670 of the sensing element 14 are shown in a state after being pressed and fixed by the fixing member 660 and the screw 675. The O-ring 670 on the sealing area 652 is compressed by the transparent plate 141. The end area of ​​the main surface of the transparent plate 141 is in contact with the support area 654. The support area 654 supports the sensing element 14 together with the O-ring 670. The O-ring 670 is under appropriate compression to achieve reliable sealing while keeping the surface of the laminated film 140 in an appropriate position (at an appropriate level).

[0156] Next, the region of the hypotenuse surface 181 of the transparent plate 141 or the prism 146 where the laminate film 140 is to be disposed is described. If the laminate film 140 is formed on the transparent plate 141 or the prism 146 without any consideration, the O-ring 670 is in contact with the laminate film 140. If the laminate film 140 has a region in contact with the O-ring 670, the film may be damaged in the contact region. Damage only at a single point may spread from there to affect the entire laminate film 140.

[0157] Fig.19 An example of the region of the laminate film 140 disposed on the hypotenuse surface 181 of the prism 146 is shown. Fig.19 The laminate film 140 has a rounded rectangular shape, but the shape of the laminate film 140 is not limited to a specific shape. The laminate film 140 may be formed directly on the hypotenuse surface 181 of the prism 146. Alternatively, the laminate film 140 may be formed on a glass plate, and the other side of the glass plate may be coupled to the hypotenuse surface 181 of the prism 148 with optical coupling oil.

[0158] like Fig.19 As shown, the entire laminated film 140 is located in the center hole of the O-ring 670. The laminated film 140 does not contact the O-ring 670. The configuration of the laminated film 140 to be used should at least satisfy the condition that the laminated film 140 is provided in an area that facilitates measurement by irradiation with measurement light, and is not provided in an area required for sealing. Not providing the laminated film 140 in an area to be in contact with the O-ring 670 protects the laminated film 140 from damage, thereby obtaining a stable and highly reliable element.

[0159] Implementation 4

[0160] FIG. 20A to FIG. 20C The airtight structure in the aforementioned embodiment is schematically shown. Fig. 20A The airtight structure in Embodiment 1 is schematically shown; Fig. 20B The airtight structure in Embodiment 2 is schematically shown; Fig. 20C The airtight structure in Embodiment 3 is schematically shown. Fig. 20A , Fig. 20B ,and Fig. 20C In the figure, the hollow arrow indicates the direction to press the prism. Press the prism to compress the O-ring.

[0161] As described above, the transparent substrates of the sensing elements in the embodiments of the present specification include prisms, and therefore, these transparent substrates exhibit high mechanical strength compared to transparent substrates made of only a thin glass plate.

[0162] As described above, the transparent substrate of the sensing element may be composed of a prism or of a prism and a transparent plate. When a large pressure difference between the hydrogen-containing gas to be tested and the ambient air is applied to the transparent plate as a thin glass plate, the transparent plate may break. Therefore, one embodiment of the present specification forms a laminated film as a gas sensing film directly on the hypotenuse surface of the prism, and uses a prism formed of a glass block as a structural member without using a thin glass plate to constitute a part of the airtight limiting wall. This configuration reduces the possibility of rupture of the sensing element. On the other hand, including a transparent plate facilitates the formation of the gas sensing film.

[0163] Fig. 20A , Fig. 20B and Fig. 20C The embodiments of the invention shown in place a sensing element including a prism at the boundary between a space for containing the gas to be tested and the outside (where a pressure difference exists), and use the structure of the sensing element as part of an airtight limiting wall. These embodiments place an O-ring between the surface of a transparent substrate on which a laminated film is disposed and the limiting wall to achieve sealing. The presence of the O-ring maintains airtightness and prevents the gas to be tested from leaking to the outside or preventing ambient air from flowing into the measurement space.

[0164] The embodiment of the present invention fixes the sensing element including the prism in a position where the O-ring is compressed to an amount that provides effective sealing properties. Even if the pressure difference between the inside and outside of the restricting wall acts on the prism, the compression amount of the O-ring does not change to an extent that affects the compression amount of the seal. Therefore, in any case where the pressure of the gas to be tested is higher or lower than the pressure of the ambient air, sufficient sealing properties are ensured.

[0165] Fig. 20A and Fig. 20B The illustrated embodiment presses the prism 146 or 446 in a direction away from the gas channel 310 containing the gas to be tested. When the gas to be tested is pressurized or at a higher pressure than the ambient air, the pressure difference acts on the O-rings 371 and 372, or the O-ring 470 in a direction that increases the deformation of the O-rings 371 and 372, or the O-ring 470. Therefore, the O-rings 371 and 372, or the O-ring 470 can reliably prevent leakage of the gas to be tested. In the case of using the transparent plate 141 in these embodiments, the optical coupling oil can be mixed in the atmosphere of the gas to be tested. Forming the stacked film 140 as the hydrogen sensing film directly on the prism 146 or 446 can avoid contamination by the optical coupling oil.

[0166] Fig. 20CThe illustrated embodiment presses the prism 146 in a direction toward the gas channel 310 containing the gas to be tested. When the gas is decompressed or at a lower pressure than the ambient air, the pressure difference acts on the O-ring 670 to increase its deformation. Therefore, the O-ring 670 can reliably prevent leakage of the gas. In the case where the sensing element includes a transparent plate 141 and the O-ring 670 is pressed by the transparent plate 141, the optical coupling oil between the transparent plate 141 and the prism 146 is located outside the space containing the gas to be tested, and therefore, contamination of the gas to be tested can be avoided. The laminated film 140 can be formed directly on the hypotenuse surface 181 of the prism 146.

[0167] The aforementioned embodiment uses an O-ring as an example of an elastic sealing member to seal the gap between the sensing element and the limiting member. In another embodiment, part or all of the sealing structure may be made of an adhesive. Specifically, the elastic sealing member may be an elastic member having a surface area made of a substance having adhesive or cohesive properties. Thus, a sealing characteristic is achieved. The cross-sectional shape of the area for mounting the sensing element is not limited to those shapes described in the embodiments, but may be a stepped structure that can stabilize the position and orientation of the prism and provide uniform compression of the O-ring.

[0168] Although the aforementioned embodiment has described the optical hydrogen sensor as an example of an optical chemical sensor, the optical chemical sensor of the present invention is not limited to a hydrogen sensor. The target to be detected by the optical chemical sensor is the concentration of the target substance, and the airtight structure of the present invention using the sensing element can be applied to various sensors, such as an optical ion sensor for detecting the pH of a liquid, an optical gas sensor for detecting a gas of a type other than hydrogen, and an optical biosensor for detecting DNA or enzymes in a liquid. As described in this specification, the object to be tested can be a fluid including a gas and a liquid. The airtight structure of the present invention, when applied to the various optical chemical sensors listed above, can exhibit the same effects as described in the aforementioned embodiment.

[0169] As described above, the optical chemical sensor in the embodiment of the present invention irradiates the sensing film formed on the transparent substrate with the measuring light incident on the lower side of the transparent substrate, and measures the target substance with the reflected light. The transparent substrate includes a prism, and the sensing film is formed on the surface of the transparent substrate. The sensing film is exposed to the test object, and the surface of the transparent substrate through which the measuring light passes is exposed to the external environment. The transparent substrate including the prism serves as a part of the limiting wall between the test object and the external environment. The gap between the transparent substrate including the prism and the other part of the limiting wall is sealed with a sealing structure.

[0170] When measuring with oblique incidence from the underside of the transparent substrate, a prism is required to eliminate direct reflections from the transparent substrate. Using a transparent substrate including such a prism as part of the confinement wall ensures sufficient mechanical strength that cannot be achieved with a thin glass substrate alone. The transparent substrate also provides functions such as confinement, optical transparency, and elimination of direct reflections from its underside, contributing to a compact and low-cost device.

[0171] As described above, the embodiments of the present invention have been described; however, the present invention is not limited to the aforementioned embodiments. Those skilled in the art can easily modify, add or convert each element in the aforementioned embodiments within the scope of the present invention. A part of the configuration of one embodiment can be replaced with the configuration of another embodiment, or the configuration of one embodiment can be incorporated into the configuration of another embodiment.

Claims

1. An optical sensor device, comprising: light source; Sensing element; Photodetector; Fixings; as well as Elastic sealing parts, Wherein, the sensing element comprises: A prism, the prism comprising a hypotenuse face and two right-angled facets; and a sensing film on the bevel surface, the sensing film being configured to sense a target substance, wherein the sensing film is exposed to an airtight space including the target substance, wherein a limiting wall defining the airtight space including the target substance has an opening, and the opening is covered by the sensing element, Wherein, the elastic sealing component is located between the sensing element and the opening, The sensing element is fixed by being pressed by the fixing member, and the pressing strength causes the elastic sealing component to deform elastically. wherein the light source and the photodetector are located outside the airtight space including the target substance, wherein the light from the light source is configured to pass through one of the two right-angled surfaces and be incident on the sensing film, wherein the light reflected from the sensing film is configured to be emitted through the other of the two right-angled surfaces, and The photodetector is configured to detect light reflected from the sensing film and emitted through the other of the two right-angled surfaces.

2. The optical sensor device according to claim 1, in, The opening is covered by the beveled surface, and Wherein, the elastic sealing component is located between the bevel surface and the limiting wall and surrounds the opening.

3. The optical sensor device according to claim 1, in, The prism also includes a conical side surface, wherein the opening is covered by the two right-angled sides and a portion of the conical side surface, and Wherein, the elastic sealing component is located between the conical side surface and the limiting wall.

4. The optical sensor device according to claim 1, in, The opening is a first opening, the elastic sealing component is a first elastic sealing component, Wherein, the optical sensor device further comprises a second elastic sealing component, The first opening is covered by the first right-angled side surface of the two right-angled side surfaces. Wherein, the first elastic sealing component is located between the first right-angle side surface and the limiting wall and surrounds the first opening. The limiting wall further has a second opening, and the second opening is covered by the second right-angled side surface of the two right-angled side surfaces. wherein the second elastic sealing component is located between the second right-angle side surface and the limiting wall and surrounds the second opening, and The prism is fixed by being pressed by the fixing member, and the pressing strength causes the first elastic sealing component and the second elastic sealing component to be elastically deformed.

5. The optical sensor device according to claim 2, in, The sensing film is formed on a transparent plate, wherein oil exists between the transparent plate and the bevel surface, wherein the elastic sealing member is located between the transparent plate and the limiting wall, and The elastic sealing component is in contact with the main surface of the transparent plate.

6. The optical sensor device according to claim 1, wherein: The sensing film is directly formed on the hypotenuse surface of the prism.

7. The optical sensor device according to claim 1, wherein: The entire sensing membrane is located in the area surrounded by the elastic sealing member.

8. The optical sensor device according to claim 1, wherein: The elastic sealing component is an O-ring.

9. The optical sensor device according to claim 1, wherein: The elastic sealing member has a surface having adhesive or bonding properties.

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