Optical gas sensor device and method for manufacturing optical gas sensor

Abstract

To reduce the influence of external environments on at least one of a light source and a light reception unit.SOLUTION: An optical gas sensor device 100a includes: a light source for emitting an infrared ray to a gas as a detection target; an optical fiber which transmits an infrared ray; a light reception unit for generating the infrared ray emitted through the optical filter and generating a detection signal; and a substrate 6. The optical gas sensor device 100a is equipped with an optical filter and has a sealing tool 20a for sealing the light source and a sealing tool 40a for sealing the light reception unit. The sealing tools 20a and 40a are equipped to the substrate 6.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an optical gas sensor device and a method for manufacturing an optical gas sensor device. [Background technology]

[0002] Conventionally, gas concentrations are constantly monitored in homes, factories, and business establishments for the purpose of managing chemical substances and ensuring the safety of workers. For gas concentration monitoring, non-dispersive infrared absorption (NDIR) gas sensors that detect the concentration of gases such as CO2 are known. NDIR gas sensors use the property of many gases absorbing their own infrared wavelengths to measure the concentration of a gas by detecting how much of each wavelength is absorbed when infrared light is radiated to the gas to be detected. For example, there is a gas sensor that has an infrared light source and a light receiving unit and detects the concentration of the gas to be detected that is located in the optical path of the light source and the light receiving unit.

[0003] Also known is a light absorption gas sensor including a light emitting diode, a ring-shaped radiation guide for guiding near infrared rays emitted from the light emitting diode, and a photodiode for detecting the guided near infrared rays (see Patent Document 1). The light emitting diode as a light source and the photodiode as a light receiving section are mounted on a printed circuit board. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2013-517467 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the light source and the light receiving part of the above-mentioned optical absorption gas sensor are exposed and mounted on a printed circuit board. It has been found that the exposed light source and light receiving part are greatly affected by the external environment (humidity, temperature, and air pressure). The amount of light emitted by the light source mainly changes depending on the external environment.

[0006] As an example, we will explain the case where the light source and light receiving unit are configured with MEMS (Micro Electro Mechanical Systems) and the air pressure drops. When the air pressure drops, the number of molecules in the air that collide with the heater surface of the light source decreases, making it difficult for heat to be taken away from the heater. In a vacuum, the state becomes a state of insulation like a thermos. In this way, when the air pressure drops, when the same energy is applied to the light source, the heat taken away by the molecules in the air decreases, and the temperature of the heater surface rises.

[0007] As mentioned above, when the light source is exposed, the amount of light in the infrared region varies depending on the type of gas molecules that come into contact with the heater surface, as well as the temperature and pressure of the environment. In this configuration, unless environmental parameters are acquired and fed back, the emission intensity will differ from that corrected at the factory, resulting in a large error and a gas concentration value that deviates from the actual value. In addition, in the case of a gas sensor module that has a function to set a threshold and issue an alert, there is a risk of a false alarm. Here, the phenomenon of the light source is shown, but the same phenomenon occurs in the light receiving section.

[0008] An object of the present invention is to reduce the influence of the external environment on at least one of a light source and a light receiving section. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides A light source that emits infrared rays to a gas to be detected; an optical filter that transmits the infrared light; a light receiving unit that detects infrared rays incident through the optical filter and generates a detection signal; A first substrate and an optical gas sensor device comprising: a sealing member on which the optical filter is mounted and which seals the light source or the light receiving unit; The encapsulant is mounted to the first substrate.

[0010] The present invention also provides a method for producing a method for manufacturing a semiconductor device comprising the steps of: A light source that emits infrared rays to a gas to be detected; an optical filter that transmits the infrared light; a light receiving unit that detects infrared rays incident through the optical filter and generates a detection signal; A method for manufacturing an optical gas sensor device comprising: a first mounting step of mounting the light source and the light receiving unit on the first substrate; a second mounting step of mounting a sealer on the first substrate, the sealer having the optical filter mounted thereon and sealing the light source or the light receiving unit; In the second mounting step, A first protective cover that surrounds the side of the light source or the light receiving unit and has an air hole connecting to the space of the light source or the light receiving unit is mounted on the first substrate, the optical filter is mounted in an opening on the upper surface of the first protective cover to form the sealing device, and after heat treatment of the mounting of the light source, the light receiving unit and circuit components on the first substrate, the air hole is sealed with an adhesive.

[0011] The present invention also provides a method for producing a method for manufacturing a semiconductor device comprising the steps of: A light source that emits infrared rays to a gas to be detected; an optical filter that transmits the infrared light; a light receiving unit that detects infrared rays incident through the optical filter and generates a detection signal; A method for manufacturing an optical gas sensor device comprising: a first mounting step of mounting the light source or the light receiving unit on a second substrate; a second mounting step of mounting a sealer on the first substrate, the sealer having the optical filter mounted thereon and sealing the light source or the light receiving unit; In the second mounting step, A first protective cover that surrounds the side of the light source or the light receiving unit and has an air hole connecting to the space of the light source or the light receiving unit is mounted on the second substrate, the optical filter is mounted in an opening on the upper surface of the first protective cover to form the sealant, and after heat treatment of the sealant and circuit components mounted on the first substrate, the air hole is sealed with an adhesive.

[0012] The present invention also provides a method for producing a method for manufacturing a semiconductor device comprising the steps of: A light source that emits infrared rays to a gas to be detected; an optical filter that transmits the infrared light; a light receiving unit that detects infrared rays incident through the optical filter and generates a detection signal; A method for manufacturing an optical gas sensor device comprising: a first mounting step of mounting the light source or the light receiving unit on a second protective cover that surrounds a side surface and a bottom surface of the light source or the light receiving unit; a creating step of mounting the optical filter on the second protective cover to create a sealer that seals the light source or the light receiving unit; a second mounting step of mounting the sealing device on the first substrate; In the preparation process, The air is decompressed, and the optical filter is mounted on the second protective cover in the decompressed air.

[0013] The present invention also provides a method for producing a method for manufacturing a semiconductor device comprising the steps of: A light source that emits infrared rays to a gas to be detected; an optical filter that transmits the infrared light; a light receiving unit that detects infrared rays incident through the optical filter and generates a detection signal; A method for manufacturing an optical gas sensor device comprising: a first mounting step of mounting the light source or the light receiving unit on a second protective cover that surrounds a side surface and a bottom surface of the light source or the light receiving unit; a creating step of mounting the optical filter on the second protective cover to create a sealer that seals the light source or the light receiving unit; a second mounting step of mounting the sealing device on the first substrate; In the preparation process, The optical filter is mounted on the second protective cover at a temperature of 100° C. or higher. Effect of the Invention

[0014] According to the present invention, the effect of the external environment on at least one of the light source and the light receiving section is reduced. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic diagram of an optical gas sensor device according to a first embodiment of the present invention. [Diagram 2] FIG. 1 is a perspective view of an optical gas sensor device. [Diagram 3] FIG. 2 is a partially transparent perspective view of the optical gas sensor device. [Figure 4] 1A is a perspective view of a sealing device according to a first embodiment, and FIG. 1B is a cross-sectional view of the sealing device according to the first embodiment. [Diagram 5] FIG. 2 is an exploded view of the sealing device according to the first embodiment. [Figure 6] 4 is a flow diagram showing a manufacturing method of the optical gas sensor device according to the first embodiment. [Figure 7] FIG. 11 is a diagram showing changes in the amount of received light during gas detection in the optical gas sensor device of a comparative example, the optical gas sensor device of the first embodiment, and the optical gas sensor device of the third embodiment. [Figure 8] FIG. 11 is a perspective view showing a sealing device according to a second embodiment. [Figure 9] 10 is a flow diagram showing a manufacturing method of the optical gas sensor device according to the second embodiment. [Figure 10] 10 is a flow diagram showing the process of making the closure of FIG. 9. [Figure 11] 10(a) is a perspective view showing a sealing device according to a third embodiment, and (b) is a cross-sectional view showing the sealing device according to the third embodiment. [Figure 12]FIG. 11 is a cross-sectional view showing a sealing device of a modified example. [Figure 13] FIG. 11 is a cross-sectional view showing a sealing device of a modified example. [Figure 14] FIG. 1 is a diagram showing the absorption wavelengths of various gases and the transmittance range of sapphire glass / Si. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, first to third embodiments and modifications of the present invention will be described in detail in order with reference to the accompanying drawings, however, the scope of the invention is not limited to the illustrated examples.

[0017] (First embodiment) A first embodiment of the present invention will be described with reference to Fig. 1 to Fig. 7. First, a schematic configuration of an optical gas sensor device 100a according to the present embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic diagram of the optical gas sensor device 100a according to the present embodiment.

[0018] As shown in Fig. 1, the optical gas sensor device 100a of this embodiment is an NDIR type gas sensor. The optical gas sensor device 100a includes an optical cover 1, a light source 2, an AR (Anti Reflection) filter 31, a λ (wavelength) selection filter 32, a light receiving unit 4, a signal processing unit 5, and a switch 81. The AR filter 31 and the λ selection filter 32 are optical filters. In the optical gas sensor device 100a, the light source 2 radiates (emits, emits) infrared rays. The radiated infrared rays are emitted to the gas G to be detected (measured) in the optical cover 1 through the AR filter 31 and an optical path (path) in the optical cover 1. The AR filter 31 is a filter that prevents reflection of infrared rays and transmits them.

[0019] Molecules of the gas G to be detected that exist in the optical path absorb the infrared light, thereby reducing the amount of light that reaches the light receiving unit 4. In the optical gas sensor device 100a, the infrared light that has been partially absorbed by the gas G to be detected is detected by the light receiving unit 4 via the λ selection filter 32. The λ selection filter 32 is a filter that transmits infrared light having an absorption wavelength of the gas G from the incident infrared light. With this configuration, the light receiving unit 4 does not receive unfiltered infrared light emitted from sources other than the light source 2, improving the signal to noise ratio (SNR) of the sensor.

[0020] The optical gas sensor device 100a processes the detection signal detected by the light receiving unit 4 using the signal processing unit 5, detects (measures) and outputs the concentration of the gas G to be detected. The switch 81 is a switch that turns on / off the light emission of the light source 2, and is included in the circuit element unit 8 described later. When gas detection is performed, the signal processing unit 5 turns on / off the light source 2 via the switch 81.

[0021] The optical cover 1 has a gas inlet port 11 as a gas inlet that is an inlet for introducing the detection target gas G. A contaminant filter 12 is attached to the gas inlet port 11. The contaminant filter 12 is, for example, a metal mesh filter or a resin porous film, and prevents foreign matter from entering from the outside.

[0022] In this manner, in the optical gas sensor device 100a, infrared light emitted from the light source 2 to the gas G to be detected is filtered by the AR filter 31 and the λ selection filter 32 and received by the light receiving unit 4. The AR filter 31 is disposed in a position near the light source 2 on the optical path downstream of the light source 2. The λ selection filter 32 is disposed in a position near the light receiving unit 4 on the optical path upstream of the light receiving unit 4.

[0023] However, the AR filter 31 may be arranged in a position near the light receiving unit 4 on the optical path upstream of the light receiving unit 4. In this configuration, the λ selection filter 32 may be arranged in a position near the light source 2 on the optical path downstream of the light source 2.

[0024] In this embodiment, the optical path of the infrared light received by the light receiving unit 4 is designed so that it reaches the light source 2 after being reflected on the inner surface of the optical cover 1. It is desirable that the inner surface of the optical cover 1 has a high reflectance, since this increases the efficiency of use of light (infrared light). Note that the optical path of the infrared light received by the light receiving unit 4 may include not only the optical path that reaches the light source 2 after being reflected on the inner surface of the optical cover 1, but also the optical path that reaches the light source 2 directly.

[0025] In this embodiment, the light source 2 and the AR filter 31 are packaged as a single component, a sealing tool 20a (described later), and the λ-selective filter 32 and the light receiving unit 4 are packaged as a single component, a sealing tool 40a (described later).

[0026] The optical gas sensor device 100a detects an alternative fluorocarbon refrigerant, which is a refrigerant for air conditioners, as the gas G to be detected. The alternative fluorocarbon is a synthetic compound (gas) refrigerant used industrially as an alternative to specific fluorocarbons (chlorofluorocarbons, abbreviated as CFCs). CFC refrigerants have a high ozone depletion potential and are a cause of destruction of the Earth's ozone layer, so replacement with hydrochlorofluorocarbon (HCFC) refrigerants, which have a low ozone depletion potential, has begun. In developed countries, there is also a shift from HCFC refrigerants to HFC refrigerants (R410A), which has an ozone depletion potential of zero.

[0027] CFC refrigerants, HCFC refrigerants, and HFC refrigerants have a high global warming potential and are known to be greenhouse gases that cause global warming. For this reason, the replacement of HFC refrigerants (R410A) with HFC refrigerants (R32) that have a lower global warming potential is being considered. In this embodiment, for example, R32, a fluorocarbon refrigerant, is detected as the gas G to be detected.

[0028] The optical gas sensor device 100a outputs various status signals based on the gas concentration value of the detected gas G to an information processing unit of the device that performs processing based on the status of the optical gas sensor device 100a. The information processing unit is, for example, an MCU (Micro Controller Unit). The status signals are, for example, a fault signal, an alarm signal, and a monitoring signal (normal signal). The fault signal indicates a fault state of the optical gas sensor device 100a. The alarm signal indicates that the concentration of the detected gas G is in an abnormal state (alarm state) that requires an alarm. The monitoring signal indicates that the concentration of the detected gas G is in a normal state. When the device is an alarm device, it issues various alarms (for example, an alarm of a fault of the optical gas sensor device 100a based on a fault signal, an alarm of an abnormality in the concentration of the detected gas G based on an alarm signal) in response to various signals received from the optical gas sensor device 100a. The device may be a device that includes the optical gas sensor device 100a and an MCU, or may be a device separate from the optical gas sensor device 100a. The above mentioned equipment includes room air conditioners, store / office air conditioners, and multi-air conditioners for buildings.

[0029] However, the gas G to be detected is not limited to R32, and may be other fluorocarbon refrigerants. Furthermore, the gas G to be detected is not limited to fluorocarbon refrigerants, and may be carbon dioxide, carbon monoxide, propane, methane, butane, ammonia, oxygen disulfide, nitrogen dioxide, nitric oxide, ozone, sulfur hexafluoride, ethylene, etc.

[0030] Next, a specific device configuration of the optical gas sensor device 100a will be described with reference to Figs. 2 to 5. Fig. 2 is a perspective view of the optical gas sensor device 100a. Fig. 3 is a partially see-through perspective view of the optical gas sensor device 100a. Fig. 4(a) is a perspective view of the sealing device 20a. Fig. 4(b) is a cross-sectional view of the sealing device 20a. Fig. 5 is an exploded view of the sealing device 20a.

[0031] As shown in Fig. 2 and Fig. 3, the optical gas sensor device 100a includes an optical cover 1, seals 20a and 40a, a signal processing unit 5, a substrate 6, a connector 7, and a circuit element unit 8. The seal 20a includes a light source 2 and an AR filter 31. The seal 40a includes a λ selection filter 32 and a light receiving unit 4. Fig. 2 also illustrates an x-axis, a y-axis, and a z-axis. These three axes are the same in the other figures. Note that the contamination filter 12 is not illustrated in Figs. 2 and 3.

[0032] The optical cover 1 is mounted on the +z side surface of the substrate 6, covers (encompasses) the sealing members 20a and 40a, and forms a hollow portion (space) inside capable of accommodating the gas G to be detected, through which the gas G to be detected is introduced into and out of the hollow portion via a gas introduction port 11. The base of the optical cover 1 is made of, for example, resin.

[0033] 2, the optical cover 1 has cover parts 110A and 110B. Cover part 110A is an upper part (+z direction side) and is butted against cover part 110B and integrated with them by a method such as adhesive or thermal caulking. Cover part 110B is a lower part (-z direction side) and is butted against cover part 110A and integrated with them by a method such as adhesive or thermal caulking.

[0034] As shown in FIG. 3, the optical cover 1 has a light guide section 13 as a hollow section into which the gas G to be detected is introduced. The light guide section 13 is a pipe-shaped optical path, and a cross section perpendicular to the axial direction is circular. The cover section 110A has a half pipe section. The cover section 110B has a half pipe section. The light guide section 13 is formed by combining the half pipe sections of the cover sections 110A and 110B. In this way, the optical cover 1 has cover sections 110A and 110B divided by the cross section of the light guide section 13 in the axial direction. As shown in FIG. 3, the light guide section 13 has a three-dimensional, approximately U-shaped shape when viewed from the top surface (the surface in the +z direction).

[0035] The inner surface of the light guide 13 is covered with an infrared reflective film. In this embodiment, gold is used as the infrared reflective film, but the material is not limited thereto. Silver or aluminum may be used as the infrared reflective film. Furthermore, in order to prevent corrosion of the metal film of the infrared reflective film as necessary, a protective film such as silicon oxide or silicon nitride may be formed on the infrared reflective film. The infrared reflective film and the protective film may be formed by plating, sputtering, vacuum deposition, or the like. For example, the optical cover 1 may be integrally formed of a metal such as aluminum using a metal 3D printer. In either case, it is preferable that the inner surface of the light guide 13 is mirror-finished to efficiently reflect infrared rays.

[0036] The light guide 13 reflects the infrared rays emitted from the light source 2 of the sealing device 20a and incident through the AR filter 31 with an infrared reflective film on the inner surface. The light guide 13 emits the reflected infrared rays to the light receiving unit 4 through the λ selection filter 32 of the sealing device 40a. In this way, the optical cover 1 plays a role of efficiently guiding the infrared rays from the light source 2 to the light receiving unit 4 as an optical path, by reflecting the infrared rays emitted from the light source 2 with the infrared reflective film, so that at least a part of the reflected light reaches the light receiving unit 4 through the λ selection filter 32.

[0037] In this embodiment, by making the light path inside the optical cover 1 into a pipe-shaped light guiding section 13 with a circular cross section, the reflection angle of the infrared ray can be kept constant in any direction in three dimensions (x-axis, y-axis, z-axis) regardless of the diameter or path of the cross section of the light guiding section 13, and the infrared ray emitted from the light source 2 can be reflected inside the light guiding section 13 and efficiently enter the light receiving section 4. Note that the cross section of the light path of the light guiding section 13 of the optical cover 1 in the axial direction may be configured to be elliptical.

[0038] Moreover, the optical path length of the infrared light from the light source 2 to the light receiving section 4 can be changed relatively easily by changing the diameter of the cross section of the light guiding section 13 .

[0039] 2 and 3, the optical cover 1 is three-dimensionally designed and formed so that the axial direction of the light guide section 13 forms a space SP on the substrate 6 below a portion of the x-axis direction (-z direction). At least a portion of the signal processing section 5 and the circuit element section 8 are disposed in the space SP and mounted on the substrate 6.

[0040] Furthermore, the cross-sectional area of ​​the cross section perpendicular to the axial direction of light-guiding section 13 is constant in the axial direction for the main portion (portions other than inlet portion 131 and outlet portion 132 described below). Since the cross-sectional area is constant, the gas concentration per unit volume of the detection target gas G that enters light-guiding section 13 is easily homogenized, and since infrared rays pass through randomly without following a specific path, it is easy to respond to changes in the gas concentration of gas G. Figure 3 shows the light path propagation state, with multiple infrared light paths within light-guiding section 13 represented by solid arrows. In this way, the infrared light paths are random within light-guiding section 13.

[0041] Moreover, the infrared light emitted from light source 2 is incident on light guiding section 13 on the -x direction side via AR filter 31. Light guiding section 13 on the -x direction side extends in the axial direction from the -z direction side to the +z direction side, then bends in an R shape, and extends linearly from the -y direction side to the +y direction side. An end of light guiding section 13 on the infrared light incident side is defined as inlet section 131. Light guiding section 13 extending on the +y direction side bends in an R shape, extends in the axial direction from the -x direction side to the +x direction side, and bends in an R shape again.

[0042] Then, light-guiding section 13 on the +x direction side extends linearly from the +y direction side to the -y direction side, then bends in an R shape and extends to the -z direction side. The infrared light that has passed through light-guiding section 13 is output to λ-selective filter 32 and light-receiving section 4. An end of light-guiding section 13 on the infrared light output side is defined as outlet section 132.

[0043] Outlet portion 132 has a tapered shape in which the cross-sectional area becomes smaller as the axial direction of light guiding portion 13 moves from the +z direction side to the -z direction side. Similarly, inlet portion 131 has a tapered shape in which the cross-sectional area becomes smaller as the axial direction of light guiding portion 13 moves from the +z direction side to the -z direction side. This makes it possible to increase the concentration of infrared rays radiated to light receiving portion 4 through light guiding portion 13.

[0044] Moreover, the cover parts 110A and 110B have hollow parts (not shown) as spaces for removing weight (removing weight). These hollow parts can reduce the weight of the optical cover 1 (the optical gas sensor device 100a).

[0045] Furthermore, the cover part 110B has a fixing pin (not shown). The fixing pin is a protrusion extending in the +z direction, and is integrated with a recess (female hole) (not shown) of the cover part 110A by abutting the fixing pin with the recess (female hole) (not shown) and by a method such as adhesion or thermal crimping. By integrating the fixing pin with the recess of the cover part 110A by abutting the fixing pin with the recess by a method such as adhesion or thermal crimping, the cover parts 110A and 110B are positioned and fixed into an integrated part.

[0046] As shown in FIG. 2, the cover 110A has gas inlets 111 and 112 as the gas introduction port 11. The cover 110B has gas inlets (gas introduction holes) 113 and 114 as the gas introduction port 11. The gas inlets 111 and 112 are holes that are opened in the -z direction from the upper surface of the cover 110A and penetrate to the light guide 13. The gas inlet 113 is a hole that is opened from the side surface of the cover 110B in the -y direction to the +y direction and penetrates to the space around (beside) the seal 20a. The space around the light source 2 is connected to the light guide 13. The gas inlet 114 is a hole that is opened from the side surface of the cover 110B in the -y direction to the +y direction and penetrates to the space around (beside) the seal 40a. The space around the sealing member 40 a is in electrical communication with the light guiding portion 13 .

[0047] Gas inlets 111 and 112 are directly connected to light guiding section 13 and remove a portion of the inner surface of light guiding section 13, resulting in a low efficiency of infrared radiation utilization. In contrast, gas inlet 113 is indirectly connected to light guiding section 13 via the space around sealing device 20a, resulting in a high efficiency of infrared radiation utilization without damaging (removing) a portion of the inner surface of light guiding section 13. Similarly, gas inlet 114 is indirectly connected to light guiding section 13 via the space around sealing device 40a, resulting in a high efficiency of infrared radiation utilization without damaging a portion of the inner surface of light guiding section 13.

[0048] The shape, size, and position of the gas introduction port 11 (gas intake ports 111, 112, 113, 114) of the optical cover 1 in FIG. 2 are merely an example, and the present invention is not limited to this.

[0049] As shown in Figures 4(a) and 4(b), the sealant 20a is mounted on the substrate 6 and hermetically seals the light source 2 and the mounting area of ​​the light source 2 on the substrate 6. The sealant 20a protects the light source 2 and the mounting area from the external environment. The external environment includes humidity and environmentally influential gases outside the sealant 20a. The sealant 20a has the light source 2, a protective cover 21, an adhesive 22, and an AR filter 31.

[0050] The light source 2 is a surface-mounted component, and is a MEMS-type light source mounted on the upper surface (the surface on the +z side) of the substrate 6. As shown in Fig. 5, the light source 2 has a membrane M of a membrane structure and electrodes E1 and E2.

[0051] The light source 2 has a structure in which, for example, a light source layer support layer, a light source layer, an electrode support layer, and a protective layer (all not shown) are laminated from the -z direction side to the +z direction side as a membrane provided on a Si substrate. The light source layer support layer has, for example, a silicon oxide film, a silicon nitride film, and an HLD (High temperature Low pressure Dielectric layer) layer from the -z direction side to the +z direction side. The light source layer is a thin film heater as a light source (metal) layer (light emitting layer) that emits infrared rays, and is made of, for example, MoSi2. The light source layer emits infrared rays having an intensity and wavelength dependency that depend on the surface temperature and surface emissivity when the membrane is heated by current passing through it. The electrode support layer has, for example, two insulator layers from the -z direction side to the +z direction side, and supports the electrode. The protective layer is an upper protective layer made of an insulator.

[0052] The light source layer is electrically connected to electrodes E1, E2 of the light source 2. Exposed portions of the electrodes E1, E2 are wire-bonded to electrode pads 61, 62 (FIG. 5) on the substrate 6, and the light source layer is energized by application of a voltage. The light source layer emits infrared rays when energized.

[0053] The light source 2 as a MEMS type light source is small and low-profile, and can realize miniaturization as a sensor module. In addition, the light source 2 as a MEMS type light source has characteristics such as a long life, low power consumption, and short response time, and can achieve low power consumption as a whole sensor module. The short response time of the MEMS type light source makes it possible to shorten the standby time after power is turned on when performing intermittent driving, and can reduce the average power consumption.

[0054] Furthermore, since light source 2 as a MEMS type light source can directly utilize the light emitted from the surface of the high temperature part, it can also be applied to the detection of gas G, which has an absorption band at high wavelengths. In addition, the area that emits infrared light from light source 2 is patterned with high precision on the flat surface of the membrane's Si substrate, and individual variation in the radiation direction is very small. This reduces variation in the amount of light received when a sensor module is constructed with light source 2, contributing to improved product yield. Furthermore, light source 2 is easily mass-produced because it is produced in bulk using MEMS technology based on silicon wafers.

[0055] The protective cover 21 is mounted on the upper surface (+z side surface) of the substrate 6, and is a cover that covers the periphery of the side surface of the light source 2 and the mounting area, and is, for example, a resin molded part. The protective cover 21 for the light source 2 reduces the distance between the MEMS light source 2 and the AR filter 31 and increases the opening width of the mounting portion of the AR filter 31 in order to ensure optical strength. The protective cover 21 for the light receiving unit 4 corresponds to the size of the light receiving unit 4.

[0056] Moreover, for the purpose of cost reduction, the protective cover 21 is designed to reduce the size of the AR filter 31 / λ selection filter 32. Moreover, for the purpose of cost reduction, the protective cover 21 is designed to minimize the mounting area on the substrate 6 (minimize the outer shape of the substrate 6). Moreover, the protective cover 21 is designed to have a groove 213, which will be described later, in order to ensure a process margin.

[0057] 5, the protective cover 21 has a recess 211, a light source hole 212, a groove 213, a protrusion 214, a vent hole 215, and a cut surface 216. The recess 211 is a substantially rectangular recess in which the AR filter 31 is attached. The height (length in the z-axis direction) of the recess 211 corresponds to the thickness of the AR filter 31. The recess 211 has the protrusion 214 and the vent hole 215 formed on the +y direction side.

[0058] The light source hole 212 is a hole in which the light source 2 is disposed, and is disposed inside the plane of the recess 211. The height (length in the z-axis direction) of the light source hole 212 is greater than the height of the light source 2.

[0059] The groove 213 is provided along the periphery of the light source hole 212 on the bottom surface of the recess 211, and is a resin pool for allowing the adhesive for the AR filter 31 to escape, and is a groove for adjusting the variation in the amount of adhesive applied during processing.

[0060] The protrusions 214 are two protrusions protruding inward from the ends of the recess 211. The ends of the AR filter 31 abut against the protrusions 214, thereby preventing the AR filter 31 from shifting position and positioning the AR filter 31 at a predetermined position within the recess 211. Note that, although the protrusions 214 are configured to be provided on one side of the recess 211, the present invention is not limited to this. For example, a configuration in which the protrusions 214 are provided on the four sides of the recess 211 is more preferable from the viewpoint of preventing the AR filter 31 from tilting when rotated.

[0061] The ventilation hole 215 is a through hole in the z-axis direction that is disposed on the +y direction side of the recess 211 and between the two protrusions of the protrusions 214, and communicates with the internal space of the light source hole 212. The ventilation hole 215 prevents the cover from floating due to the expansion of gas in the protective cover 21 caused by the adhesive (epoxy resin as a thermosetting resin) when mounting the protective cover 21 on the substrate 6. The ventilation hole 215 is disposed inside the adhesive application area for mounting the protective cover 21 on the substrate 6. The ventilation hole 215 is disposed between the two protrusions 214 so as not to be blocked by the AR filter 31. The ventilation hole 215 has a diameter of, for example, 0.1 mm.

[0062] The cut surface 216 is a C-plane cut formed at one end of the protective cover 21 on the +x direction side and the +y direction side. The cut surface 216 serves as a reference (index) for the front / back and direction of the protective cover 21 in various processes during the manufacture of the sealing device 20a. For example, when the protective cover 21 is placed in a jig (tray), a plurality of storage sections are arranged in the jig. Each storage section is formed with a convex portion corresponding to the cut surface 216. Each protective cover 21 is placed in each storage section with the same front / back and direction due to the cut surface 216 and the convex portion.

[0063] The adhesive 22 is a UV (Ultra Violet) curing adhesive, and after the AR filter 31 is mounted in the light source hole 212, the adhesive 22 closes the ventilation hole 215 to hermetically seal the internal space including the light source 2 of the sealing tool 20a.

[0064] The AR filter 31 is a filter that prevents reflection of infrared rays and transmits them. The AR filter 31 has, for example, a silicon substrate as a base material and a multilayer film. The multilayer film is formed on the silicon substrate by coating or the like, and is made of ZnS or Ge as a dielectric material having a smaller refractive index than silicon. The spectral characteristics of the AR filter 31 are θ=0[°], T(AVE) 8.5-10.0[μm]≧80[%], T(ABS) 8.0-12[μm]≧50[%], T(ABS) 1.0-6.8[μm]≦1.0[%], and T7.5±0.4[μm]=5[%].

[0065] The sealing device 40a has the same structure as the sealing device 20a. That is, the sealing device 40a has a configuration in which the AR filter 31 and the light source 2 of the sealing device 20a are replaced with a λ selective filter 32 and a light receiving unit 4. For this reason, a description of the protective cover of the sealing device 40a and the like will be omitted, and only the λ selective filter 32 and the light receiving unit 4 will be described.

[0066] The light receiving unit 4 is a surface mount component mounted on the +z side of the substrate 6, detects the amount of incident infrared light, and outputs a detection signal as an analog electrical signal. The light receiving unit 4 is, for example, a thermopile type optical sensor (infrared sensor) having multiple thermocouples. However, the light receiving unit 4 may also be an infrared sensor of various types shown in the following Table I.

[0067] [Table 1]

[0068] The λ-selecting filter 32 is a filter that is provided to cover the light-emitting surface of the light source 2 and transmits light (infrared light) of wavelength λ corresponding to the absorption wavelength specific to the detection target gas G. In this way, the transmission wavelength of the λ-selecting filter 32 is designed to match the absorption wavelength specific to the detection target gas G. This suppresses changes in the amount of light caused by gases other than the detection target gas G, and improves the signal-to-noise ratio of the detection signal of the light-receiving unit 4.

[0069] The λ selection filter 32 has, for example, a silicon substrate as a base material, and a dielectric multilayer film or a multilayer film made of an infrared-transmitting material such as Si, Ge, sulfide, and fluoride. The silicon substrate is a planar silicon substrate. However, the material of the substrate is not limited to silicon, and Ge (germanium), quartz, alumina, BaF2 (barium fluoride), CaF2 (calcium fluoride), etc. can be used. The multilayer film is a film with a plurality of layers provided on both sides of the silicon substrate. The planar shape of the λ selection filter 32 is rectangular, but is not limited thereto, and may be other shapes such as circular.

[0070] The λ selection filter 32 is a long-pass filter that cuts off light on the shorter wavelength side than an arbitrary cutoff wavelength and transmits light on the longer wavelength side including the absorption wavelength of the gas G. The λ selection filter 32 may also be a band-pass filter that transmits light in a wavelength band including the absorption wavelength of the gas G.

[0071] The signal processing unit 5 is mounted on a planar area other than the optical cover 1 on the +z side surface of the substrate 6, and is an AFE (Analog Front End)-IC (Integrated Circuit) serving as an electronic component (processor) that performs signal processing on the detection signal of the light receiving unit 4. The signal processing unit 5 amplifies and AD converts the analog detection signal of the light receiving unit 4, and generates a difference value between the detection value when the light source 2 is on and the detection value when the light source 2 is off. The signal processing unit 5 performs corrections for temperature and individual variations of the optical gas sensor device 100a on the difference value of the detection values, and generates various status signals from the difference value of the digital detection values. The signal processing unit 5 outputs the difference value of the digital detection values ​​and the status signal.

[0072] The substrate 6 is a PCB (Printed Circuit Board) of FR-4 (Flame Retardant Type-4) in which conductor wiring is printed on a plate such as glass epoxy resin. The optical cover 1, sealing members 20a, 40a, a signal processing unit 5, a connector 7, and a circuit element unit 8 are mounted on the +z side of the substrate 6. The +z side of the substrate 6 is approximately parallel to the light emitting surface of the light source 2, the AR filter 31, the λ selection filter 32, and the light receiving surface of the light receiving unit 4.

[0073] The connector 7 is mounted on a planar area on the +z side of the substrate 6 other than the optical cover 1 and the signal processing unit 5, and is a connector for outputting various digital signals output from the signal processing unit 5 to an information processing unit of a downstream device (e.g., an alarm). The connector 7 is connected to the information processing unit of the device via a cable having a plug.

[0074] The circuit element unit 8 is composed of circuit elements such as switches such as the switch 81, amplifiers, chip resistors, and chip capacitors. The switch 81 is composed of an NMOSFET (N-channel Metal-Oxide-Semiconductor Field Effect Transistor), a CMOS (Complementary Metal-Oxide-Semiconductor), or the like.

[0075] Next, a method for manufacturing the optical gas sensor device 100a will be briefly described with reference to Fig. 6. Fig. 6 is a flow diagram showing the method for manufacturing the optical gas sensor device 100a of this embodiment.

[0076] In the method for manufacturing the optical gas sensor device 100a, for the sake of simplicity, each manufacturing step for manufacturing the optical gas sensor device 100a using various manufacturing devices will be described.

[0077] 6, first, a master substrate designed to have a plurality of substrates 6 arranged thereon is produced as a substrate for the optical gas sensor device 100a (step S31). In parallel with step S31, a wafer including a plurality of light sources 2 is produced (step S11). Then, the wafer produced in step S11 is diced into individual pieces by a dicing device to produce the individual light sources 2 (step S12).

[0078] Since the light source 2 has a membrane structure, it is preferable to apply stealth dicing technology in step S12. This is because, with a general dicing device that uses a blade, water hits the membrane during cutting and the membrane is damaged. Stealth dicing is a dicing method in which a modified layer is formed inside the work by concentrating a laser inside the work, and chips are divided using a tape expander or the like.

[0079] In parallel with step S31, a wafer including a plurality of light receiving units 4 is created (step S13). Then, the wafer created in step S13 is diced into individual pieces by a dicing device to create individual light receiving units 4 (step S14). Since the light receiving units 4 also have a membrane structure like the light source 2, stealth dicing technology is applied in step S14.

[0080] Next, the light source 2 created in step S12 and the light receiving unit 4 created in step S14 are mounted (Chips On Board) on the mother board created in step S31 (step S32). In step S32, the light receiving unit 4 and the light source 2 are die-bonded to the mounting positions on the board 6 using an adhesive. After that, the board 6 to which the light receiving unit 4 and the light source 2 are die-bonded is heated to thermally harden the adhesive. Next, the electrodes E1 and E2 of the light source 2 and the light receiving unit 4 are electrically connected to the electrode pads 61 and 62 on the board 6 via wires such as gold wires, copper wires, and aluminum wires by wire bonding. This wire bonding is a low-loop wire bonding, which can reduce the height of the light source 2 and the light receiving unit 4 (sealing devices 20a and 40a). In general wire bonding, the first bonding is performed on the electrode pad on the chip, so the height from the chip surface to the highest point of the wire is about 150 to 180 μm, which is high. In low-loop wire bonding, the first bond is made on the substrate side, and the second bond is made on the electrode pad on the chip, so the height of the wire in the first bond is offset by the thickness of the chip, and the height of the wire on the chip can be kept low. In low-loop wire bonding, the height from the chip surface, such as the light source 2 and the light receiving unit 4, to the highest point of the wire is 100 μm or less.

[0081] To create the λ-selective filter 32, first, a multilayer film for the λ-selective filter 32 is formed on a silicon substrate (step S15). Next, the silicon substrate after the film formation created in step S15 is diced into individual pieces by a dicing device to create individual λ-selective filters 32 (step S16).

[0082] The AR filter 31 is produced by forming a multilayer film for the AR filter 31 on a silicon substrate (step S17). Next, the silicon substrate after the film formation produced in step S17 is divided into individual pieces by a dicing device or the like to produce individual AR filters 31 (step S18).

[0083] The protective cover 21 is produced by resin molding (step S19).

[0084] Next, the protective cover 21 created in S19 and the AR filter 31 and λ selection filter 32 created in steps S18 and S16 are mounted on the mother board (step S33). In step S33, epoxy resin is applied as an adhesive to a predetermined position around the light source 2 mounted on the mother board in step S32, and epoxy resin is also applied to a predetermined position around the light receiving unit 4. Next, the protective cover 21 is mounted on a predetermined position on the adhesive around the light source 2 and the light receiving unit 4. Furthermore, epoxy resin is applied to each groove 213, and the AR filter 31 / λ selection filter 32 are attached to each recess 211. Thereafter, the epoxy resin is thermally cured by heating to, for example, 120° C., and each protective cover 21 to which the AR filter 31 / λ selection filter 32 is attached is mounted on the mother board.

[0085] The signal processing unit 5 is fabricated by forming elements and wiring them by a normal semiconductor integrated circuit manufacturing technology to create a wafer including a plurality of signal processing units 5 (AFE-IC) (step S21). The wafer created in step S21 is diced into individual pieces by a dicing device, and packaged to create individual signal processing units 5 (step S22). In this case, for example, a WLCSP (Wafer Level Chip Size / Scale Package) may be used in which the wafer is diced with all parts sealed except for the electrodes of each chip, and the chips are diced into individual pieces in the resulting packaged state.

[0086] Additionally, each element such as an amplifier and a transistor that constitute the circuit element section 8 is prepared (step S23).

[0087] Next, the signal processing unit 5 in step S22 and each element constituting the circuit element unit 8 in step S23 are surface mounted on the substrate 6 using SMT (Surface Mount Technology) (step S34). In step S34, a dedicated printer prints solder paste at predetermined positions on the mother substrate on which the signal processing unit 5 and each element constituting the circuit element unit 8 are to be mounted. Thereafter, the signal processing unit 5 and each element constituting the circuit element unit 8 are mounted at predetermined positions on the mother substrate using a cassette, and the mother substrate on which the solder paste has been printed is heated to a maximum of 260° C. in a reflow furnace to solder the terminals of each element constituting the signal processing unit 5 and the circuit element unit 8 to the terminals of the wiring on the mother substrate.

[0088] Next, underfill (liquid curable resin) is applied to the mounting portion of the signal processing unit 5 and the circuit element unit 8 and is thermally cured (step S35). In step S35, the mother board is heated at 120° C. to thermally cure the underfill, thereby protecting the signal processing unit 5 and the circuit element unit 8.

[0089] Next, adhesive 22 is applied to ventilation hole 215 and is irradiated with ultraviolet light to harden adhesive 22 and fill and close ventilation hole 215 (step S36).

[0090] On the other hand, the optical cover 1 is produced by molding the cover portions 110A and 110B with resin and integrating them by a method such as adhesion or thermal caulking (step S24).

[0091] Next, after the contaminant filter 12 is created (step S25), the contaminant filter 12 is attached to the gas intake ports 111, 112, 113, and 114 of the optical cover 1 by using an adhesive or the like (step S26).

[0092] The optical cover 1 produced in step S26 is mounted at a predetermined position on the mother board by adhesion (thermosetting resin) or thermal caulking (step S37).

[0093] Next, the connector 7 is created (step S27), and the connector 7 is soldered to a predetermined position on the mother board (step S38). Thereafter, in order to make the board 6 moisture-proof and insulate it, a moisture-proof coating is applied to the mother board on which the components are mounted in step S38 (step S39). The moisture-proof coating is a coating method in which a moisture-proof coating material (e.g., HumiSeal 1B51NSLU) is applied to the board 6.

[0094] Next, the mother board on which the components are mounted in step S38 is divided into individual boards 6 by a dicing device, and individual optical gas sensor devices 100a are produced (step S40). In this case, it is preferable to use a dry dicer that does not use water as the dicing device.

[0095] Various adjustments are made to the optical gas sensor device 100a created in step S40 (step S41). Then, a final inspection is made on the optical gas sensor device 100a adjusted in step S41 (step S42). Finally, the optical gas sensor device 100a determined to be non-defective in the final inspection in step S41 is packaged and shipped to the destination (step S43). Through the manufacturing process described above, the optical gas sensor device 100a is manufactured.

[0096] Next, the effects of the sealing devices 20a and 40a will be described with reference to Fig. 7. Fig. 7 is a diagram showing changes in the amount of received light during gas detection in the optical gas sensor device of a comparative example, the optical gas sensor device 100a of the present embodiment, and the optical gas sensor device 100c of the third embodiment.

[0097] As shown in Fig. 7, an optical gas sensor device in which the light source 2 and the light receiving section 4 are exposed and not sealed, and an optical gas sensor device 100a of this embodiment are used. The optical gas sensor device 100c will be described later. The optical gas sensor device in which the light source 2 and the light receiving section 4 are exposed is referred to as an "optical gas sensor device of a comparative example." In Fig. 7, two bar graphs are drawn for each optical gas sensor device. The bar graph on the left corresponds to a light receiving area of ​​the light receiving section 4 having a size of □ (square) 0.710 [mm]. The bar graph on the right corresponds to a light receiving area of ​​the light receiving section 4 having a size of □ 1.090 [mm].

[0098] Since light source 2 is sealed (protective cover 21), a smaller light source is used than the exposed light source of the comparative example. For example, the following Table II shows the light emitting area [mm], area ratio of the light emitting area (the area ratio of the light source of the comparative example is set to 1), and total light emission amount [W] of the exposed light source of the comparative example and light source 2 which has been made smaller for sealing. Due to its smaller size, light source 2 has a smaller light emitting area, area ratio, and total light emission amount than the exposed light source of the comparative example. [Table 2]

[0099] The vertical axis in Fig. 7 indicates the change [%] in the amount of received light during gas detection for each optical gas sensor device. The change [%] in the amount of received light during gas detection is the change [%] in the amount of received light based on the amount of received light during gas detection using the light receiving section 4 of the optical gas sensor device of the comparative example, which has a light receiving area of ​​0.710 mm. This reference (target value) amount of received light (amount of change) is set to 100 [%]. The change [%] in the amount of received light during gas detection of the optical gas sensor device 100a also includes the effect of the miniaturization of the light source 2 described above.

[0100] The optical path length is extended and the optical characteristics are deteriorated by sealing the light source 2 and the light receiving unit 4. For this reason, the light receiving area of ​​the light receiving unit 4 is changed to ensure the amount of light received, while the design of the protective cover 21 is optimized to reduce the effect of the deterioration of the optical characteristics.

[0101] In the optical gas sensor device of the comparative example, the amount of light received when the light receiving area is 1.090 mm is larger than the amount of light received when the light receiving area is 0.710 mm. The optical gas sensor device 100a is also provided with a light receiving section 4 with a light receiving area of ​​0.710 mm. Then, the amount of light received is reduced (55%) from the standard (target value) amount of light received by the optical gas sensor device of the comparative example. However, in the optical gas sensor device 100a, the light receiving section 4 with a light receiving area of ​​1.090 mm is replaced. Then, the amount of light received by the optical gas sensor device 100a is increased (123%) from the standard amount of light received by the optical gas sensor device of the comparative example, which is preferable. In this way, the light receiving area of ​​the light receiving section 4 can be adjusted to reduce the adverse effects of sealing.

[0102] The dimensions of the sealing member 20a are shown in Table III below. The sealing members 20b and 20c will be described later. [Table 3]

[0103] As described above, according to this embodiment, the optical gas sensor device 100a includes the light source 2 that emits infrared rays to the gas G to be detected, the AR filter 31 and the λ selection filter 32 as optical filters that transmit infrared rays, the light receiving unit 4 that detects the infrared rays incident through these optical filters and generates a detection signal, and the substrate 6. The optical gas sensor device 100a includes a seal 20a on which the AR filter 31 is mounted and seals the light source 2, and a seal 40a on which the λ selection filter 32 is mounted and seals the light receiving unit 4. The seals 20a and 40a are mounted on the substrate 6.

[0104] Therefore, the light source 2 and the light receiving unit 4 are sealed and isolated from the external environment by the sealing members 20a and 40a, thereby reducing the influence of the external environment on the light source 2 and the light receiving unit 4. In addition, the gas concentration of the gas G to be detected can be accurately detected based on the detection signal.

[0105] Moreover, the AR filter 31 transmits infrared light while preventing reflection. The λ selection filter 32 transmits infrared light having a wavelength corresponding to the absorption wavelength of the detection target gas G. Therefore, the AR filter 31 can reduce stray infrared light. The λ selection filter 32 can accurately detect the gas concentration of the detection target gas G based on the detection signal.

[0106] Furthermore, the sealant 20a seals the light source 2 and the electrical connection parts (wires, electrodes E1, E2, etc.) of the light source 2. The sealant 40a seals the light receiving unit 4 and the electrical connection parts (wires, electrodes E1, E2, electrode pads 61, 62, etc.) of the light receiving unit 4. This makes it possible to isolate the electrical connection parts of the light source 2 and the light receiving unit 4 from the external environment, such as the humidity of the outside air, and to prevent deterioration of the connection parts.

[0107] Furthermore, the sealing device 20a has a protective cover 21 that surrounds the side surface of the light source 2. The sealing device 40a has a protective cover 21 that surrounds the side surface of the light receiving unit 4. The AR filter 31 is mounted in an opening on the upper surface of the protective cover 21 of the sealing device 20a. The λ selection filter 32 is mounted in an opening on the upper surface of the protective cover 21 of the sealing device 40a. Therefore, the light source 2 and the light receiving unit 4 can be easily sealed and hermetically sealed by the AR filter 31, the λ selection filter 32, and the protective cover 21.

[0108] Furthermore, the protective cover 21 of the sealing device 20a has an air hole 215 that connects to the space of the light source 2. The protective cover 21 of the sealing device 40a has an air hole 215 that connects to the space of the light receiving unit 4. The air hole 215 is blocked with the adhesive 22. Therefore, the air hole 215 allows the AR filter 31 to be easily mounted on the sealing device 20a, and the λ selection filter 32 to be easily mounted on the sealing device 40a. Furthermore, by blocking the air hole 215 with the adhesive 22, the light source 2 and the light receiving unit 4 can be hermetically sealed.

[0109] Furthermore, the light source 2 and the light receiving portion 4 of the sealing members 20a and 40a are directly mounted on the substrate 6. This makes it possible to reduce the material cost and size of the sealing members 20a and 40a.

[0110] The optical gas sensor device 100a also includes an optical cover 1 that guides infrared light emitted from the light source 2 to the light receiving section 4 via the gas G to be detected. The optical cover 1 is mounted on a substrate 6. Therefore, the optical cover 1 allows the gas concentration of the gas G to be detected more accurately.

[0111] Also, an optical gas sensor device 100a is manufactured, which includes a light source 2 that emits infrared rays to the gas G to be detected, an AR filter 31 and a λ selection filter 32 as optical filters that transmit infrared rays, a light receiving unit 4 that detects the infrared rays incident through these optical filters and generates a detection signal, and a substrate 6. The manufacturing method of the optical gas sensor device 100a includes a first mounting step (step S32) of mounting the light source 2 and the light receiving unit 4 on the substrate 6, and a second mounting step (steps S33 to S36) of mounting a sealer 20a on which the AR filter 31 is mounted and seals the light source 2, and a sealer 40a on which the λ selection filter 32 is mounted and seals the light receiving unit 4 on the substrate 6. In the second mounting step, a protective cover 21 that surrounds the side surface of the light source 2 and has a vent hole 215 that connects to the space of the light source 2 is mounted on the substrate 6, and the AR filter 31 is mounted on an opening on the upper surface of the protective cover 21 to form the sealer 20a. Similarly, a protective cover 21 that surrounds the side surface of the light receiving unit 4 and has a vent hole 215 that connects to the space of the light receiving unit 4 is mounted on the substrate 6, and the λ selection filter 32 is mounted in an opening on the upper surface of the protective cover 21 to form a sealant 40a. After heat treatment of the mounted light source 2, light receiving unit 4, and circuit components (signal processing unit 5, circuit element unit 8), the vent hole 215 is sealed with an adhesive.

[0112] Therefore, the light source 2 and the light receiving unit 4 are hermetically sealed by the sealants 20a, 40a, so that the influence of the external environment on the light source 2 and the light receiving unit 4 can be reduced. Also, the gas concentration of the gas G to be detected can be accurately detected. Such an optical gas sensor device 100a can be manufactured. Also, it is possible to prevent the protective cover 21 from floating due to thermal expansion of the gas inside the protective cover 21 caused by the adhesive when mounting the protective cover 21 on the substrate 6. Furthermore, since the light source 2 and the light receiving unit 4 are directly mounted on the substrate 6, the material cost and size of the sealants 20a, 40a can be reduced.

[0113] The adhesive 22 is a UV-curable resin, which can prevent the cover from floating due to thermal expansion of the gas inside the protective cover 21 when the adhesive 22 is cured.

[0114] The manufacturing method of the optical gas sensor device 100a also includes a fourth mounting step (step S37) of mounting the optical cover 1 on the substrate 6, which guides the infrared rays emitted from the light source 2 to the light receiving part 4 via the gas G to be detected. Therefore, the optical cover 1 makes it possible to more accurately detect the gas concentration of the gas G to be detected.

[0115] (Second embodiment) A second embodiment of the present invention will be described with reference to Fig. 8 to Fig. 10. Fig. 8 is a perspective view showing a sealing device 20b. Fig. 9 is a flow diagram showing a manufacturing method of the optical gas sensor device 100b of this embodiment. Fig. 10 is a flow diagram showing a process of producing the sealing device of Fig. 9.

[0116] In the optical gas sensor device 100a of the first embodiment, the sealing device 20a, 40a is configured such that the light source 2 and the light receiving unit 4 are directly mounted on the substrate 6, which is the parent substrate. In the present embodiment, the sealing device is configured such that the light source 2 and the light receiving unit 4 are mounted on a child substrate other than the substrate 6.

[0117] The device configuration of this embodiment uses an optical gas sensor device 100b instead of the optical gas sensor device 100a of the first embodiment. However, in the optical gas sensor device 100b, the same parts as those in the optical gas sensor device 100a are denoted by the same reference numerals and their description will be omitted.

[0118] The optical gas sensor device 100b includes an optical cover 1, seals 20b and 40b, a signal processing section 5, a substrate 6, a connector 7, and a circuit element section 8. The seal 20b will be described with reference to FIG.

[0119] The sealing device 20b includes the light source 2, the protective cover 21, the adhesive 22, the AR filter 31, and a daughter board 63. The daughter board 63 is made of the same material as the board 6, but is a separate board from the board 6, and is mounted on the upper surface of the board 6. The protective cover 21 is mounted on the daughter board 63. The daughter board 63 electrically connects the light source 2 and a terminal wire-bonded to a terminal of the board 6 by, for example, a through hole.

[0120] The sealer 40b includes a light receiving unit 4, a protective cover 21, an adhesive 22, a λ selective filter 32, and a child substrate 63, similar to the sealer 20b.

[0121] Next, a method for manufacturing the optical gas sensor device 100b will be described with reference to FIGS.

[0122] 9, first, a master substrate designed to have a plurality of substrates 6 arranged thereon is produced as a substrate for the optical gas sensor device 100b (step S71). However, each substrate 6 of the master substrate produced in step S71 is designed so that a sealer 20b, 40b is mounted thereon instead of a protective cover 21 in a later process.

[0123] Meanwhile, a sealer producing step is carried out to produce the sealers 20b and 40b (step S50). Here, the sealer producing step S50 will be described with reference to FIG.

[0124] First, a daughter board designed to have a plurality of daughter boards 63 arranged thereon is created as a board for sealing devices 20b and 40b (step S101). Steps S91 to S94 are the same as steps S11 to S14 in Fig. 6. Steps S95 and S96 are the same as steps S15 to S18 in Fig. 6. Step S97 is the same as step S19 in Fig. 6.

[0125] Next, the multiple protective covers 21 created in step S97 are manually placed in a storage portion of the jig and aligned, and each protective cover 21 is subjected to plasma treatment (step S98). The plasma treatment is a process for cleaning and modifying the surface of each protective cover 21 with Ar+. The plasma treatment activates the surface of each protective cover 21, increasing and stabilizing the adhesive strength in the subsequent bonding.

[0126] Next, the light source 2 created in step S92 and the light receiving unit 4 created in step S94 are mounted on the child board created in step S31 (step S102). In step S102, an adhesive is pasted on the child board at the mounting positions of the light receiving unit 4 and the light source 2, and the light receiving unit 4 and the light source 2 are die-bonded. Then, an operator heats the child board to which the light receiving unit 4 and the light source 2 are die-bonded, and thermally hardens the adhesive.

[0127] Next, the electrodes E1, E2 of the die-bonded light source 2 and light receiving unit 4 are electrically connected to the electrode pads on the daughter board by wire bonding (step S103). After that, the protective cover 21, which has been plasma-treated in step S98 and aligned on the jig, is attached to the daughter board (step S104). In step S104, epoxy resin is applied as an adhesive to a predetermined position around the light source 2 mounted on the daughter board, and epoxy resin is also applied to a predetermined position around the light receiving unit 4. After that, the protective cover 21 on the jig is attached to a predetermined position on the epoxy resin around the light source 2 and the light receiving unit 4.

[0128] Next, the AR filter 31 / λ-selecting filter 32 are mounted in each recess 211 by a general-purpose die bonding device, and the adhesive is thermally cured (step S105). In step S105, epoxy resin is applied to each groove 213, and the AR filter 31 / λ-selecting filter 32 is bonded to each recess 211. Thereafter, the epoxy resin is thermally cured by heating to, for example, 120° C. in an oven, and each protective cover 21 with the AR filter 31 / λ-selecting filter 32 attached thereto is fixed to the child board.

[0129] Next, a mark (such as the date of manufacture) is printed on the back surface of the child board 63 by a laser marker for each sealing device 20b / 40b to ensure traceability (step S106). After that, the child board on which the components were mounted in step S38 is divided into individual child boards 63 by a dicing device, and sealing devices 20b and 40b are created (step S107).

[0130] Next, the sealing devices 20b, 40b are inspected (performance evaluation, pass / fail judgment), and the products judged to be pass are packed into a tray (step S108). In the inspection, the resistance value is measured to judge whether the wires are shorted when the sealing devices 20b, 40b are packaged. Then, the sealing devices 20b, 40b packed into the tray are stored (step S109).

[0131] Returning to Fig. 9, steps S61 to S67 are the same as steps S21 to S27 in Fig. 6. The sealers 20b, 40b on the tray created in step S50, the signal processing unit 5 created in step S62, and the circuit element unit 8 created in step S63 are surface-mounted together on the mother board created in step S71 (step S72). Steps S73 to S80 are the same as steps S36 to S43 in Fig. 6.

[0132] Additionally, specific examples of dimensions of the closure 20b are given in Table III.

[0133] As described above, according to the present embodiment, the sealing device 20b has a child board 63 on which the light source 2 is mounted. The sealing device 40b has a child board 63 on which the light receiving unit 4 is mounted. Therefore, the sealing devices 20b, 40b can be created and stored without directly mounting the light source 2 and the light receiving unit 4 on the board 6. In addition, since the sealing devices 20b, 40b are mounted on the board 6, the light source 2 and the light receiving unit 4 can be indirectly and easily mounted on the board 6.

[0134] The manufacturing method of the optical gas sensor device 100b includes a first mounting step (steps S102 and S103) of mounting the light source 2 and the light receiving unit 4 on the child board 63, and a second mounting step (steps S72 and S73) of mounting, on the child board 63, a sealer 20b on which the AR filter 31 is mounted and seals the light source 2, and a sealer 40b on which the λ selection filter 32 is mounted and seals the light receiving unit 4. In the second mounting step, a protective cover 21 that surrounds the side of the light source 2 and has a vent hole 215 that connects to the space of the light source 2 is mounted on the child board 63, and the AR filter 31 is mounted on the opening on the upper surface of the protective cover 21 to form the sealer 20b. Similarly, a protective cover 21 that surrounds the side of the light receiving unit 4 and has a vent hole 215 that connects to the space of the light receiving unit 4 is mounted on the child board 63, and the λ selection filter 32 is mounted on the opening on the upper surface of the protective cover 21 to form the sealer 40b. After the sealing members 20b, 40b and the circuit components (signal processing section 5, circuit element section 8) are mounted on the substrate 6 and then heat treated, the ventilation hole 215 is sealed with an adhesive.

[0135] Therefore, the sealants 20b, 40b can be created and stored without directly mounting the light source 2 and the light receiving unit 4 on the substrate 6. Also, since the sealants 20b, 40b are mounted on the substrate 6, the light source 2 and the light receiving unit 4 can be indirectly and easily mounted on the substrate 6. Furthermore, when mounting the sealants 20b, 40b on the substrate 6, it is possible to prevent the cover from floating due to thermal expansion of the gas in the protective cover 21 caused by the adhesive.

[0136] (Third embodiment) A third embodiment of the present invention will be described with reference to Figures 11(a) and 11(b). Figure 11(a) is a perspective view showing a sealing device 20c. Figure 11(b) is a cross-sectional view showing the sealing device 20c.

[0137] In the optical gas sensor apparatus 100b of the second embodiment, the sealing device 20b, 40b has a configuration in which the protective cover 21 is made of resin and the child substrate 63 corresponds to the bottom surface. In the present embodiment, the sealing device has a protective cover made of ceramic and has a bottom surface.

[0138] The device configuration of this embodiment uses an optical gas sensor device 100c instead of the optical gas sensor device 100b of the second embodiment. However, in the optical gas sensor device 100c, the same parts as those in the optical gas sensor device 100b are denoted by the same reference numerals and the description thereof will be omitted.

[0139] The optical gas sensor device 100c includes an optical cover 1, sealants 20c and 40c, a signal processing unit 5, a substrate 6, a connector 7, and a circuit element unit 8. The sealant 20c will be described with reference to Figs. 11(a) and 11(b).

[0140] The sealing device 20c includes a light source 2, a protective cover 21c, and an AR filter 31. The protective cover 21c is made of ceramic and is a cover that protects the side and bottom surfaces of the light source 2. The protective cover 21c is mounted on a substrate 6. Moreover, compared to the protective cover 21 of the sealing device 20a of the first embodiment, the protective cover 21c does not have an air hole, and an AR filter 31 is mounted thereon.

[0141] The protective cover 21c has recesses 211c and 212c. The recess 211c is a recess arranged on the upper surface (+z direction) side, and the planar shape of the opening is rectangular. The recess 212c is a recess arranged on the lower surface (-z direction) side of the recess 211c, and the planar shape of the opening is rectangular and smaller than the recess 211c. The recess 212c has a bottom surface. The light source 2 is mounted on the bottom surface of the recess 212c. The protective cover 21c electrically connects the terminal wire-bonded to the light source 2 to the terminal of the substrate 6 by, for example, a through hole.

[0142] The AR filter 31 is disposed over the entire upper surface of the protective cover 21c so as to cover the opening on the upper surface. The AR filter 31 is attached to the protective cover 21c by an adhesive 33. The adhesive 33 is an epoxy resin or a silicone resin for hermetically sealing the light source 2. The adhesive 33 may be a glass frit material for sealing the light source 2, or a preform or paste of a metal material such as AuSn or solder. In the case of a metal material, it is desirable to apply metallization such as Cr / Ni / Au or Ti / Ni / Au to the adhesive portion of the protective cover 21c and the AR filter 31, which are the adherends, in order to ensure adhesion.

[0143] The sealing tool 40c includes a light receiving unit 4, a protective cover 21c, and a λ selection filter 32. In this manner, the sealing tool 40c has a configuration in which the light source 2 and the AR filter 31 of the sealing tool 20c are replaced with the light receiving unit 4 and the λ selection filter 32.

[0144] Next, a method for manufacturing the optical gas sensor device 100c will be described. In the method for manufacturing the optical gas sensor device 100c, the seal making process of step S50 in Fig. 9 of the second embodiment is replaced with a process for making seals 20c and 40c. However, step S73 is not included.

[0145] The process of making the sealer 20c is as follows. First, the protective cover 21c is prepared as a cavity-type ceramic substrate. Next, the light source 2 is mounted (die bonding + wire bonding) on ​​the protective cover 21c. After that, as a compensation for the absence of an air hole, for example, an air suction pump is used to reduce the air pressure (e.g., vacuum drawing), and the adhesive 33 is applied to the protective cover 21c in the reduced pressure air (e.g., vacuum), and the AR filter 31 is attached and mounted to create the sealer 20c. Alternatively, the AR filter 31 is attached at a temperature higher than room temperature (100°C or higher) according to the physical properties of the adhesive material. At this time, in order to suppress an increase in internal pressure due to a temperature increase, the filter 31 is fixed so as not to move with a weight, a jig, or the like. At this time, it is desirable to mount the filter 31 at a higher temperature in order to reduce the load of the fixation.

[0146] The process for producing the sealant 40c is the same as the process for producing the sealant 20c. First, the protective cover 21c is prepared as a cavity-type ceramic substrate. Next, the light receiving unit 4 is mounted on the protective cover 21c. After that, the adhesive 33 is applied to the protective cover 21c, and the λ selection filter 32 is attached and mounted to produce the sealant 40c.

[0147] This blocks the external environment from the surface of the light source 2 or the light receiving unit 4, thereby minimizing the influence of the external environment. In addition, the height (length in the z-axis direction) of the recess 212c is adjusted to shorten the distance between the AR filter 31 or the λ selection filter 32 and the surface of the light source 2 or the light receiving unit 4.

[0148] Also, unlike the child board method of the second embodiment (storage of the sealers 20b, 40b on a tray), the sealers 20c, 40c are delivered (stored) as individual pieces. Therefore, in order to create a pseudo-aggregated board, the sealers 20c, 40c are mounted on a jig with a recessed pocket. In the SMT of the sealers 20c, 40c (corresponding to step S50 in FIG. 9), the sealers 20c, 40c on the jig are surface-mounted on the board 6.

[0149] Next, the effects of the sealing members 20c, 40c of the optical gas sensor device 100c of this embodiment will be described with reference to FIG.

[0150] The optical gas sensor device 100c has a light receiving section 4 with a light receiving area of ​​0.710 mm. As a result, the amount of received light is reduced (76%) compared to the reference (target) amount of received light of the optical gas sensor device of the comparative example. However, in the optical gas sensor device 100c, the light receiving section 4 with a light receiving area of ​​1.090 mm is replaced. As a result, the amount of received light of the optical gas sensor device 100c is increased (167%) compared to the reference amount of received light of the optical gas sensor device of the comparative example, which is preferable. In this way, the light receiving area of ​​the light receiving section 4 can be adjusted to reduce the adverse effects of sealing.

[0151] Additionally, specific examples of dimensions of closure 20c are given in Table III.

[0152] As described above, according to this embodiment, the sealing device 20c has a protective cover 21c that surrounds the side and bottom surfaces of the light source 2. The sealing device 40c has a protective cover 21c that surrounds the side and bottom surfaces of the light receiving unit 4. The AR filter 31 is mounted on an opening on the upper surface of the protective cover 21c of the sealing device 20c. The λ selection filter 32 is mounted on an opening on the upper surface of the protective cover 21c of the sealing device 40c. Therefore, the sealing devices 20c, 40c can be created and stored without directly mounting the light source 2 and the light receiving unit 4 on the board 6. In addition, the sealing devices 20c, 40c do not mount a child board, so that the structure can be simplified. In addition, since the sealing devices 20c, 40c are mounted on the board 6, the light source 2 and the light receiving unit 4 can be indirectly and easily mounted on the board 6.

[0153] The manufacturing method of the optical gas sensor device 100c includes a first mounting step of mounting the light source 2 and the light receiving unit 4 on the protective cover 21c, a fabrication step of mounting the AR filter 31 on the protective cover 21c to fabricate a sealer 20c that seals the light source 2, and mounting the λ selection filter 32 on the protective cover 21c to fabricate a sealer 40c that seals the light receiving unit 4, and a second mounting step of mounting the sealers 20c, 40c on the substrate 6. In the fabrication step, air is decompressed, and the AR filter 31 is mounted on the protective cover 21c in the decompressed air, and the λ selection filter 32 is mounted on the protective cover 21c.

[0154] Therefore, the sealers 20c, 40c can be created and stored without directly mounting the light source 2 and the light receiving unit 4 on the substrate 6. Also, since the sealers 20c, 40c are mounted on the substrate 6, the light source 2 and the light receiving unit 4 can be indirectly and easily mounted on the substrate 6. Furthermore, since the air in the internal space of the sealers 20c, 40c is decompressed, it is possible to prevent the cover from floating due to thermal expansion of the gas in the protective cover 21c caused by heat treatment in a stage prior to mounting the sealers 20c, 40c on the substrate 6.

[0155] In the above-mentioned manufacturing process, the AR filter 31 may be mounted on the protective cover 21c, and the λ selection filter 32 may be mounted on the protective cover 21c at a temperature of 100° C. or higher. This method also makes it possible to prevent the cover from floating due to thermal expansion of the gas in the protective cover 21c caused by the heat treatment in the stage prior to mounting the sealing members 20c and 40c on the substrate 6.

[0156] (Modification) A modified example of the third embodiment will be described with reference to Figures 12 and 13. Figure 12 is a cross-sectional view showing a sealing device 20d. Figure 13 is a cross-sectional view showing a sealing device 20e.

[0157] The optical gas sensor device 100c of the third embodiment may be configured to include seals 20d, 40d of this modification instead of the seals 20c, 40c. As shown in Fig. 12, the seal 20d includes a light source 2, a protective cover 21d, and an AR filter 31. The protective cover 21d is made of ceramic, like the seal 20c, and is mounted on the substrate 6.

[0158] The protective cover 21d has recesses 211d, 212d, and 213d. The recess 211d is a recess arranged on the upper surface (+z direction) side, and the planar shape of the opening is rectangular, which corresponds to the planar shape of the AR filter 31. The recess 212d is a recess arranged on the lower surface (-z direction) side of the recess 211d, and the planar shape of the opening is rectangular and smaller than that of the recess 211d. The recess 213d is a recess arranged on the lower surface side of the recess 212d, and the planar shape of the opening is rectangular and smaller than that of the recess 212d. The recess 213d has a bottom surface. The light source 2 is mounted on the bottom surface of the recess 212d. The protective cover 21d electrically connects the terminal wire-bonded to the light source 2 to the terminal of the substrate 6 by, for example, a through hole.

[0159] The sealing device 40d includes a light receiving unit 4, a protective cover 21d, and a λ selection filter 32. In this manner, the sealing device 40d has a configuration in which the light source 2 and the AR filter 31 of the sealing device 20d are replaced with the light receiving unit 4 and the λ selection filter 32.

[0160] The manufacturing process of the sealing device 20d is similar to that of the sealing device 20c, but when mounting the AR filter 31 on the protective cover 21d, the worker mounts the AR filter 31 by dropping it into the recess 211d to which the adhesive 33 has been applied. This configuration increases the bonding area of ​​the AR filter 31, thereby improving the bonding strength, improving the degree of sealing, and facilitating the manufacturing process (the AR filter 31 can be pressed down from above and hardened).

[0161] The process for producing the sealant 40d is similar to the process for producing the sealant 20d, and the light receiving unit 4 is mounted on the protective cover 21d.

[0162] Moreover, the optical gas sensor device 100c of the third embodiment may be configured to include the sealers 20e, 40e of this modification instead of the sealers 20c, 40c. As shown in Fig. 13, the sealer 20e includes a light source 2, a protective cover 21e, and an AR filter 31. The protective cover 21e is made of ceramic, like the sealer 20c, and is mounted on the substrate 6.

[0163] The protective cover 21e has recesses 211e and 212e. The recess 211e is a recess arranged on the upper surface (+z direction) side, and the planar shape of the opening is rectangular, which corresponds to the planar shape of the AR filter 31. The recess 212e is a recess arranged on the lower surface (-z direction) side of the recess 211e, and the planar shape of the opening is rectangular and smaller than that of the recess 211e. The recess 212e has a bottom surface. The light source 2 is mounted on the bottom surface of the recess 212e. The protective cover 21e electrically connects the terminal wire-bonded to the light source 2 to the terminal of the substrate 6 by, for example, a through hole.

[0164] The sealing device 40e includes a light receiving unit 4, a protective cover 21e, and a λ selection filter 32. In this manner, the sealing device 40e has a configuration in which the light source 2 and the AR filter 31 of the sealing device 20e are replaced with the light receiving unit 4 and the λ selection filter 32.

[0165] The process for producing the sealant 20e is similar to the process for producing the sealant 20d. The process for producing the sealant 40e is similar to the process for producing the sealant 20e, and the light receiving unit 4 is mounted on the protective cover 21e.

[0166] As described above, the sealing devices 20d, 40d, 20e, and 40e of the present modified examples have the same effects as the sealing devices 20c and 40c of the third embodiment.

[0167] It should be noted that the description of the above embodiment is merely an example of the optical gas sensor device and the manufacturing method of the optical gas sensor device according to the present invention, and the present invention is not limited to this.

[0168] For example, the cavity (recess) of the protective covers 21c, 21d, and 21e of the third embodiment and the modified example may have an increased gold (Au) area. This configuration has the effect of increasing the amount of effective infrared light. This is because gold has a high reflectance R [%] of 98 [%] or more at wavelengths of 1 [μm] or more, which is the infrared region. Other than gold, aluminum (Al), copper (Cu), silver (Ag), and the like may also be used to increase the cavity region because they have a high reflectance R [%] in the infrared region.

[0169] In the optical gas sensor device in the above embodiment and modification, the gas G is R32, and the base material of the AR filter 31 and the λ selection filter 32 of the sealing member is silicon (Si). However, the present invention is not limited to this configuration. Figure 14 is a diagram showing the absorption wavelength [μm] of various gases and the transmittance range of sapphire glass / Si.

[0170] As shown in Fig. 14, when the gas G to be detected is R32, the absorption wavelength of R32 is in the 9 to 10 [μm] band. For this reason, Si, which has a transmittable range in the absorption wavelength band of R32, is used as the base material of the AR filter 31 and the λ selection filter 32. For example, in the case of gas G having a short absorption wavelength, the selectivity is improved by preventing stray light, etc., by using sapphire glass as the base material of the AR filter 31 and the λ selection filter 32. Gas G having a short absorption wavelength is CO2, CH4, etc.

[0171] In the above embodiment and modified example, the optical gas sensor device includes one set of the light source 2, the AR filter 31, the λ selection filter 32, and the light receiving unit 4, but is not limited to this. The optical gas sensor device may include a plurality of sets of the light source 2, the AR filter 31, the λ selection filter 32, and the light receiving unit 4.

[0172] In the above embodiment and modified example, the optical gas sensor device has a configuration in which the light source 2 and the light receiving unit 4 are sealed in a sealer, but the present invention is not limited to this. For example, either the light source 2 or the light receiving unit 4 may be sealed in a sealer.

[0173] In the sealing members 20a, 40a of the first embodiment and the sealing members 20b, 40b of the second embodiment, the protective cover 21 may not have the ventilation hole 215, and the AR filter 31 or the λ selection filter 32 may be attached to the protective cover 21 in the depressurized air, as in the protective cover 21c of the third embodiment. In the sealing members 20c, 40c of the third embodiment and the sealing members 20d, 40d, 20e, 40e of the modified examples, the protective covers 21c, 21d, 21e may have ventilation holes, and the AR filter 31 or the λ selection filter 32 may be attached to the protective covers 21c, 21d, 21e, and the ventilation holes may be filled and blocked with an adhesive after the heat treatment of mounting each element constituting the circuit element unit 8 on the substrate 6.

[0174] Furthermore, the detailed configurations and operations of the optical gas sensor devices 100a, 100b, and 100c in the above-described embodiments and modifications may be modified as appropriate without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0175] 100a, 100b, 100c Optical gas sensor device G Gas 1 Optical cover 110A, 110B Cover part 11 Gas inlet port 111,112,113,114 Gas intake 12 Contamination Filter 13 Light guide section 131 Entrance 132 Exit section SP space part 20a,40a,20b,40b,20c,40c,20d,40d,20e,40e Sealing tool 2 light source M Membrane E1,E2 electrode 21, 21c, 21d, 21e Protective cover 211, 211c, 212c, 211d, 212d, 213d, 211e, 212e Concave 212 Light source hole 213 Groove 214 Protrusion 215 Ventilation hole 216 Cut Surface 22,33 Adhesive 31 AR Filter 32 λ selection filter 4 Light receiving section 5. Signal Processing Section 6 Substrate 61,62 Electrode pads 63 Sub-board 7 Connectors 8 Circuit Element Section 81 Switch

Claims

1. A light source that emits infrared rays to a gas to be detected; an optical filter that transmits the infrared light; a light receiving unit that detects infrared rays incident through the optical filter and generates a detection signal; A first substrate and an optical gas sensor device comprising: a sealing member on which the optical filter is mounted and which seals the light source or the light receiving unit; The sealing member is mounted on the first substrate.

2. 2. The optical gas sensor device according to claim 1, wherein the optical filter is at least one of an AR filter that prevents reflection of the infrared light and transmits it, and a λ-selective filter that transmits infrared light of a wavelength corresponding to an absorption wavelength of the gas to be detected.

3. 2. The optical gas sensor device according to claim 1, wherein the sealing member seals an electrical connection portion of the light source or the light receiving portion.

4. The sealing device has a first protective cover that surrounds a side surface of the light source or the light receiving unit, 2. The optical gas sensor device according to claim 1, wherein the optical filter is mounted in an opening in an upper surface of the first protective cover.

5. the first protective cover has an air hole communicating with a space of the light source or the light receiving unit, 5. The optical gas sensor device according to claim 4, wherein the vent hole is sealed with an adhesive.

6. 5. The optical gas sensor device according to claim 4, wherein the light source or the light receiving portion of the sealing member is directly mounted on the first substrate.

7. the sealing device has a second substrate on which the light source or the light receiving unit is mounted, 5. The optical gas sensor device according to claim 4, wherein the second substrate is mounted on the first substrate.

8. the sealing device has a second protective cover that surrounds a side surface and a bottom surface of the light source or the light receiving unit, 2. The optical gas sensor device according to claim 1, wherein the optical filter is mounted in an opening in an upper surface of the second protective cover.

9. an optical cover that guides the infrared light emitted from the light source to the light receiving unit via the gas to be detected; The optical gas sensor device according to claim 1 , wherein the optical cover is mounted on the first substrate.

10. A light source that emits infrared rays to a gas to be detected; an optical filter that transmits the infrared light; a light receiving unit that detects infrared rays incident through the optical filter and generates a detection signal; A method for manufacturing an optical gas sensor device comprising: a first mounting step of mounting the light source and the light receiving unit on the first substrate; a second mounting step of mounting a sealer on the first substrate, the sealer having the optical filter mounted thereon and sealing the light source or the light receiving unit; In the second mounting step, A method for manufacturing an optical gas sensor device, comprising the steps of: mounting a first protective cover on the first substrate, the first protective cover surrounding a side surface of the light source or the light receiving unit and having an air hole connecting to the space of the light source or the light receiving unit; mounting the optical filter in an opening on the top surface of the first protective cover to form the sealant; and sealing the air hole with an adhesive after heat treatment of the mounting of the light source, the light receiving unit and circuit components on the first substrate.

11. A light source that emits infrared rays to a gas to be detected; an optical filter that transmits the infrared light; a light receiving unit that detects infrared rays incident through the optical filter and generates a detection signal; A method for manufacturing an optical gas sensor device comprising: a first mounting step of mounting the light source or the light receiving unit on a second substrate; a second mounting step of mounting a sealer on the first substrate, the sealer having the optical filter mounted thereon and sealing the light source or the light receiving unit; In the second mounting step, A method for manufacturing an optical gas sensor device, comprising the steps of: mounting a first protective cover on the second substrate, the first protective cover surrounding a side surface of the light source or the light receiving portion and having an air hole connecting to a space of the light source or the light receiving portion; mounting the optical filter in an opening on the top surface of the first protective cover to form the sealant; and sealing the air hole with an adhesive after heat treatment of the sealant and circuit components mounted on the first substrate.

12. 12. The method for manufacturing an optical gas sensor device according to claim 10, wherein the adhesive is a UV curable resin.

13. A light source that emits infrared rays to a gas to be detected; an optical filter that transmits the infrared light; a light receiving unit that detects infrared rays incident through the optical filter and generates a detection signal; A method for manufacturing an optical gas sensor device comprising: a first mounting step of mounting the light source or the light receiving unit on a second protective cover that surrounds a side surface and a bottom surface of the light source or the light receiving unit; a creating step of mounting the optical filter on the second protective cover to create a sealer that seals the light source or the light receiving unit; a second mounting step of mounting the sealing device on the first substrate, In the preparation process, A method for manufacturing an optical gas sensor device, comprising the steps of: performing a decompression process on the air; and mounting the optical filter on the second protective cover in the decompressed air.

14. A light source that emits infrared rays to a gas to be detected; an optical filter that transmits the infrared light; a light receiving unit that detects infrared rays incident through the optical filter and generates a detection signal; A method for manufacturing an optical gas sensor device comprising: a first mounting step of mounting the light source or the light receiving unit on a second protective cover that surrounds a side surface and a bottom surface of the light source or the light receiving unit; a creating step of mounting the optical filter on the second protective cover to create a sealer that seals the light source or the light receiving unit; a second mounting step of mounting the sealing device on the first substrate, In the preparation process, The method for manufacturing an optical gas sensor device includes mounting the optical filter on the second protective cover at a temperature of 100° C. or higher.

15. 15. The method for manufacturing an optical gas sensor device according to claim 10, 11, 13 or 14, wherein the optical filter is at least one of a lambda selective filter that transmits infrared light having a wavelength corresponding to an absorption wavelength of the gas to be detected, and an AR filter that transmits the infrared light while preventing its reflection.

16. 15. The method for manufacturing an optical gas sensor device according to claim 10, wherein the sealing member seals an electrical connection portion of the light source or the light receiving portion.

17. 15. The method for manufacturing an optical gas sensor device according to claim 10, further comprising a third mounting step of mounting an optical cover on the first substrate, the optical cover directing infrared light emitted from the light source to the light receiving portion via the gas to be detected.

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