Gas detection device

Abstract

To provide a gas detector capable of outputting a highly stable detection signal.SOLUTION: A gas detector 1 comprises: a light-emitting section 10 that emits light in a wavelength band including a wavelength absorbed by gas to be detected; a light-receiving section 20 having sensitivity in the wavelength band; a package 40 including the light-emitting section 10 and the light-receiving section 20; a light guide section 50 that guides the light to the light-receiving section 20; a joint section 60 that joins the package 40 and the light guide section 50; and a heat insulating section 70 provided in a gap between the package 40 and the light guide section 50. A part of a surface of the package 40 which faces the light guide section 50 has a proximate region D in which distance between the package 40 and the light guide section 50 is equal to or less than 500 μm, and at least a part of the heat insulating section 70 and at least a part of the joint section 60 are provided adjacent to a part of the proximate region D.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a gas detection device.

Background Art

[0002] Conventionally, gas detection devices have been used in various fields. For example, a light-emitting unit that emits infrared rays and a detector that detects infrared rays of a specific wavelength are arranged inside a case having an ellipsoidal mirror, and a gas detection device that detects a gas to be detected is known (see, for example, Patent Document 1).

[0003] In recent years, there has been an increasing demand for mounting gas detection devices on portable devices such as smartphones, and they are becoming smaller and thinner (see, for example, Patent Document 2). Since electronic components mounted on portable devices are mounted at extremely high densities, they have a high heat generation density, and from the perspective of the waterproof function, the airtightness of the device housing is high, resulting in a design that easily traps heat. In addition, the heat flow generated by heat sources such as power supplies, cameras, and arithmetic units mounted on portable devices mainly diffuses to the surroundings through the substrate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] For example, as shown in Figure 4, in the conventional gas detection device 1B, the package 40B and the light guide section 50B are directly joined without any intervening joints, and the package 40B, which has a small heat capacity, and the light guide section 50B, which has a large heat capacity, are not thermally insulated from each other. As a result, the heat flow generated at the heat source flows more to the light guide section 50B than to the package 40B via the substrate 100B, making it difficult to achieve a uniform temperature inside the package 40B.

[0006] As a result, the temperatures of the light-emitting unit 10B, light-receiving unit 20B, and control unit 30B contained within the package 40B became uneven, leading to a problem where the output signal of the gas detection device 1B became unstable. Furthermore, this problem became more pronounced as the size of the gas detection device 1B decreased.

[0007] In view of these circumstances, the object of the present invention is to provide a gas detection device capable of outputting a highly stable detection signal. [Means for solving the problem]

[0008] A gas detection device according to one embodiment includes a light-emitting unit that emits light in a wavelength band including wavelengths absorbed by the gas to be detected, a light-receiving unit that is sensitive to the wavelength band, a package that encloses the light-emitting unit and the light-receiving unit, a light-guiding unit that guides the light to the light-receiving unit, a joining unit that joins the package and the light-guiding unit, and a thermal insulating unit provided in the gap between the package and the light-guiding unit, wherein a part of the surface of the package facing the light-guiding unit has a proximity region where the distance between the package and the light-guiding unit is 500 μm or less, and at least a part of the thermal insulating unit and at least a part of the joining unit are provided adjacent to the part of the proximity region. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a gas detection device that can output a highly stable detection signal. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic cross-sectional view showing an example of the configuration of a gas detection device according to one embodiment of the present invention. [Figure 2A] This is a perspective view showing an example of the configuration of a gas detection device according to one embodiment of the present invention. [Figure 2B] This is a plan view showing an example of the configuration of a gas detection device according to one embodiment of the present invention. [Figure 3] This is a schematic cross-sectional view showing an example of the configuration of a gas detection device according to a modified example. [Figure 4] This is a schematic cross-sectional view showing an example of the configuration of a conventional gas detection device. [Modes for carrying out the invention]

[0011] Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. In principle, identical components will be given the same reference numeral, and redundant explanations will be omitted. For the sake of clarity, the aspect ratios of each component in each drawing are exaggerated from their actual proportions.

[0012] Furthermore, for the sake of clarity in the following explanation, "upper" will refer to the light guide side as depicted in the drawing, and "lower" will refer to the substrate side as depicted in the drawing. However, "upper" and "lower" are merely terms defined for convenience and should not be interpreted restrictively.

[0013] <Gas detection device> An example of the configuration of the gas detection device 1 according to this embodiment will be described with reference to Figures 1, 2A, and 2B.

[0014] The gas detection device 1 is mounted on a substrate 100 and is an NDIR (Non-Dispersive InfraRed) type device that detects the concentration of a gas based on the amount of infrared radiation absorbed by the introduced gas. The gas detection device 1 is a small device, for example, measuring 7 mm in length, 5 mm in width, and 3 mm in height. Examples of gases to be detected include carbon dioxide, methane, water vapor, propane, formaldehyde, carbon monoxide, nitric oxide, ammonia, sulfur dioxide, and alcohol.

[0015] The gas detection device 1 includes a light emitting unit 10, a light receiving unit 20, a control unit 30, a package 40, a light guiding unit 50, a joining unit 60, and a thermal insulation unit 70.

[0016] 〔Light emitting unit〕 The light emitting unit 10 emits light in a wavelength band including a wavelength absorbed by the detected gas in accordance with a drive current or a drive voltage supplied from the control unit 30. The light emitting unit 10 emits light, for example, in a wavelength band of 2.0 μm or more and 12.0 μm or less in wavelength.

[0017] The light emitting unit 10 is, for example, an LED (Light Emitting Diode), a lamp, a laser (light amplification by stimulated emission of radiation), an organic light emitting element, a MEMS (Micro Electro Mechanical Systems) heater, a VCSEL (Vertical Cavity Surface Emitting LASER), or the like.

[0018] The light emitting unit 10 is enclosed in the package 40. In the gas detection device 1, since a thermal insulation unit 70a is provided in a gap S1 between the package 40 and the light guiding unit 50, the thermal insulation between the package 40 and the light guiding unit 50 is enhanced. Therefore, even if a heat flow enters the gas detection device 1, it is difficult for the heat flow to flow into the light guiding unit 50, so the temperature inside the package 40 quickly becomes uniform, and the temperature of the light emitting unit 10 enclosed in the package 40 also quickly stabilizes.

[0019] The upper surface of the light emitting unit 10 may be in contact with the thermal insulation unit 70b. By providing the thermal insulation unit 70b on the upper surface of the light emitting unit 10, the temperature of the light emitting unit 10 can be further stabilized.

[0020] The light emitting unit 10 is preferably enclosed in the package 40, but may be provided outside the package 40 if it can maintain a temperature substantially equal to that of the light receiving unit 20 and the control unit 30 (with an error of about ±0.1 °C).

[0021] The light emitting unit 10 may further include an optical filter having a function of selectively transmitting light in a part of the wavelength band.

[0022] 〔Light receiving unit〕 The light receiving unit 20 has sensitivity in a wavelength band including the wavelength absorbed by the detected gas, and receives the light transmitted through the detected gas. The light receiving unit 20 receives, for example, light in the wavelength band of 2.0 μm or more and 12.0 μm or less in wavelength. The light receiving unit 20 outputs a detection signal indicating the concentration of the detected gas to the control unit 30 according to the amount of received light of the received light. The higher the concentration of the detected gas, the smaller the amount of received light of the light received by the light receiving unit 20, and the lower the concentration of the detected gas, the larger the amount of received light of the light received by the light receiving unit 20.

[0023] The light receiving unit 20 is, for example, a photodiode, a phototransistor, a thermopile, a pyroelectric sensor, a bolometer, a photoacoustic detector, or the like.

[0024] The light receiving unit 20 is enclosed in the package 40. In the gas detection device 1, since the heat insulating part 70a is provided in the gap S1 between the package 40 and the light guide part 50, the thermal insulation between the package 40 and the light guide part 50 is enhanced. Therefore, even if a heat flow flows into the gas detection device 1, it is difficult for the heat flow to flow into the light guide part 50, so the temperature inside the package 40 quickly becomes uniform, and the temperature of the light receiving unit 20 enclosed in the package 40 also quickly stabilizes.

[0025] The upper surface of the light receiving unit 20 may be in contact with the heat insulating part 70b. By providing the heat insulating part 70b on the upper surface of the light receiving unit 20, the temperature of the light receiving unit 20 can be further stabilized.

[0026] The light-receiving unit 20 is preferably enclosed within the package 40, but it may be provided outside the package 40 if it can maintain a temperature approximately equal to that of the light-emitting unit 10 and the control unit 30 (with an error of about ±0.1°C).

[0027] The light-receiving unit 20 may further include an optical filter that has the function of selectively transmitting light in a certain wavelength range.

[0028] [Control Unit] The control unit 30 may include at least one general-purpose processor that performs functions according to the program to be read, and a dedicated processor specialized for specific processing. The dedicated processor may include an Application Specific Integrated Circuit (ASIC) or non-volatile / volatile memory.

[0029] The control unit 30 controls the light-emitting unit 10 and the light-receiving unit 20. For example, if the light-receiving unit 20 is not used in the gas detection device 1, the control unit 30 can control only the light-emitting unit 10 independently.

[0030] The control unit 30 is enclosed within the package 40. In the gas detection device 1, a thermal insulation section 70a is provided in the gap S1 between the package 40 and the light guide section 50, resulting in high thermal insulation between the package 40 and the light guide section 50. Therefore, even if a heat flow enters the gas detection device 1, the heat flow is less likely to flow into the light guide section 50, causing the temperature inside the package 40 to quickly become uniform, and the temperature of the control unit 30 enclosed within the package 40 to quickly stabilize.

[0031] The control unit 30 is preferably enclosed within the package 40, but it may also be located outside the package 40 or outside the gas detection device 1.

[0032] 〔package〕 The package 40 is joined to the light guide portion 50 by the joint portion 60. The joining of the package 40 and the light guide portion 50 via the joint portion 60 creates a gap S1 between the package 40 and the light guide portion 50.

[0033] Package 40 encloses the light-emitting unit 10, the light-receiving unit 20, and the control unit 30. In the gas detection device 1, a thermal insulation part 70a is provided in the gap S1 between package 40 and light guide unit 50, thus improving the thermal insulation between package 40 and light guide unit 50. Therefore, even if a heat flow enters the gas detection device 1, the heat flow is less likely to flow into the light guide unit 50, so the internal temperature of package 40 quickly becomes uniform (temperature uniformity effect). Furthermore, since a thermal insulation part 70b is provided in the detection space S2 between package 40 and light guide unit 50, in contact with the upper surface of the light-emitting unit 10 and the upper surface of the light-receiving unit 20, the problem of uneven temperature inside package 40 due to structural non-uniformity of light guide unit 50 is less likely to occur. As a result, the light-emitting unit 10, light-receiving unit 20, and control unit 30 enclosed in package 40 quickly become uniform in temperature and can maintain a steady temperature state.

[0034] The package 40 contains the light-emitting unit 10, the light-receiving unit 20, and the control unit 30, as well as metal components such as metal wires 41 for electrically connecting these elements and a lead frame 42 for enabling electrical connection to the outside.

[0035] The package 40 has a protrusion X that contacts the light guide portion 50. Because the package 40 has a protrusion X that contacts the light guide portion 50, even if the thickness of the joint portion 60 becomes too thin during the mass production process, for example, a gap S1 can be formed between the package 40 and the light guide portion 50, and the distance between the package 40 and the light guide portion 50 can be maintained to a certain extent (for example, about 2 μm to 5 μm). Therefore, by providing a thermal insulating portion 70a in this gap S1, the thermal insulation between the package 40 and the light guide portion 50 can be improved.

[0036] The protrusion X may be intentionally manufactured, but it may also be, for example, a protrusion on the lead frame 42 that is formed unintentionally. By using a protrusion as the protrusion X, a special manufacturing process for forming the protrusion X is unnecessary, and a gap S1 can be easily formed between the package 40 and the light guide 50.

[0037] The package 40 preferably has a metal content of 25% or more, and more preferably 33% or more. The higher the metal content of the package 40, the lower its thermal resistance. Therefore, by having a metal content within this range, heat can be quickly dissipated inside the package 40, and the temperature inside the package 40 can be quickly made uniform.

[0038] The package 40 only needs to have a uniform internal temperature, and this temperature is not particularly limited. At a minimum, it is sufficient if the temperature errors of the light-emitting unit 10, the light-receiving unit 20, and the control unit 30 can be kept to about ±0.1°C.

[0039] The package 40 is preferably formed from an insulating material, such as a thermosetting resin such as epoxy resin, or a thermosetting resin obtained by mixing silica filler with such resin.

[0040] The metal wire 41 is preferably made of a good conductor, such as a metal such as gold, an alloy, or aluminum. The lead frame 42 is preferably made of a good conductor, such as a metal such as copper, an alloy, or carbon. If the lead frame 42 is made of copper with high thermal conductivity (thermal conductivity: 398 W / m·K), the heat flow can be quickly transferred to the package 40, further enhancing the temperature uniformity effect.

[0041] [Light guide section] The light guide unit 50 guides the light emitted by the light-emitting unit 10 to the light-receiving unit 20 by reflecting it once or multiple times in the detection space S2. The light-emitting unit 10 and the light-receiving unit 20 are optically connected via the light guide unit 50.

[0042] The light guide portion 50 is joined to the package 40 by the joint portion 60. The joining of the package 40 and the light guide portion 50 via the joint portion 60 creates a gap S1 between the package 40 and the light guide portion 50.

[0043] The light guide unit 50 includes an ellipsoidal mirror, the inner surface of which is a mirror. The light guide unit 50 may further include optical elements such as a plane mirror, a concave mirror or a convex mirror, a lens, or a diffraction grating.

[0044] Mirrors are made from materials such as metal, glass, ceramics, and stainless steel.

[0045] From the viewpoint of improving sensitivity, it is preferable that the mirror be made of a material with a low light absorption coefficient and high reflectivity. Examples of such materials include alloys containing aluminum, gold, and silver, dielectrics, or resin housings coated with laminates thereof. Examples of resin housing materials include LCP (liquid crystal polymer), PP (polypropylene), PEEK (polyether ether ketone), PA (polyamide), PPE (polyphenylene ether), PC (polycarbonate), PPS (polyphenylene sulfide), PMMA (polymethyl methacrylate resin), or rigid resins which are mixtures of two or more of these.

[0046] From the viewpoint of improving reliability and suppressing deterioration over time, the mirror is preferably formed from a resin housing coated with a gold or gold-containing alloy layer. Furthermore, to increase reflectivity, it is preferable to form a dielectric laminate on the surface of the metal layer. When the inner surface of the light guide section 50 is formed by vapor deposition or plating on the resin housing, productivity can be improved and weight can be reduced. In addition, when the inner surface of the light guide section 50 is formed by vapor deposition or plating on the resin housing, the difference in thermal expansion coefficients between the package 40 and the light guide section 50 is reduced, so thermal deformation can be suppressed and fluctuations in sensitivity can be suppressed.

[0047] The manufacturing process for the light guide portion 50 is not particularly limited, but for example, it may be formed by cutting. Alternatively, the light guide portion 50 may be formed by injection molding, taking into consideration productivity and other factors.

[0048] The light guide unit 50 further comprises a gas port 51 and a dust filter 52. The gas port 51 is a port for introducing the gas to be detected into the detection space S2 or for diverting the gas to be detected from the detection space S2. The dust filter 52 is attached to the gas port 51 and is a filter for preventing dust, dirt, etc. from entering the detection space S2.

[0049] The gas port 51 is preferably provided on the upper part of the light guide section 50. Providing the gas port 51 on the upper part of the light guide section 50 makes it easier to attach the dust filter 52 to the gas port 51 and simplifies the manufacturing process of the light guide section 50. The gas port 51 may also be provided on the side of the light guide section 50. If the gas port 51 is provided on the side of the light guide section 50, the position of the gas port 51 may be adjusted so that at least the gas port 51 does not come into contact with the joint section 60 and the thermal insulation section 70. In addition, the gas to be detected may be prevented from being introduced into the detection space S2 from anywhere other than the gas port 51.

[0050] [Joint part] The joint portion 60 joins the package 40 and the light guide portion 50. At least a part of the joint portion 60 is provided adjacent to the thermal insulation portion 70 in a part of the proximity region D described later. The joint portion 60 and the thermal insulation portion 70 may be provided with other members in between, but it is preferable that they be provided in direct contact. The joint portion 60 is preferably 2 μm or more and 500 μm or less in thickness. By the thickness of the joint portion 60 meeting this range, even if the package 40 does not have a protrusion X, a gap S1 can be formed between the package 40 and the light guide portion 50, and the distance between the package 40 and the light guide portion 50 can be maintained to a certain extent.

[0051] The joint portion 60 is preferably formed from a thermosetting material. For example, the joint portion 60 is preferably formed from a thermosetting resin such as epoxy resin, a resin to which a ceramic material has been added, or a metal paste. Furthermore, the joint portion 60 may contain beads, fillers, etc. The inclusion of beads, fillers, etc. in the joint portion 60 prevents the joint portion 60 from becoming too thin during the mass production process.

[0052] The joint 60 is formed by, for example, applying a resin material to the package 40, placing the light guide 50 on the package 40, and then subjecting the applied resin material to a temperature curing process.

[0053] Although some heat flow does pass through the joint 60 to the light guide 50, its speed is very slow. Therefore, unlike conventional gas detection devices 1B, the problem of heat flowing more to the light guide 50B than to the package 40B, resulting in uneven temperature distribution inside the package 40B, can be avoided.

[0054] [Thermal insulation part] The thermal insulation portion 70 is provided in the space between the package 40 and the light guide portion 50, and has the function of improving the thermal insulation between the package 40 and the light guide portion 50. For example, the thermal insulation portion 70a is provided in the gap S1 between the package 40 and the light guide portion 50. For example, the thermal insulation portion 70b is provided in the detection space S2 between the package 40 and the light guide portion 50.

[0055] By providing a thermal insulation portion 70a in the gap S1 between the package 40 and the light guide portion 50, the thermal insulation between the package 40 and the light guide portion 50 can be improved. As a result, even if a heat flow enters the gas detection device 1, the heat flow is less likely to flow into the light guide portion 50, so the temperature inside the package 40 quickly becomes uniform. Due to the temperature uniformity effect, the light-emitting portion 10, the light-receiving portion 20, and the control portion 30 enclosed in the package 40 also quickly become uniform in temperature. This enables the gas detection device 1 to output a highly stable detection signal.

[0056] Furthermore, by providing a thermal insulation section 70b in the detection space S2 between the package 40 and the light guide section 50, the temperature of the light-emitting section 10 and the light-receiving section 20 can be stabilized. In addition, the problem of uneven temperature inside the package 40 due to structural non-uniformity of the light guide section 50 is less likely to occur. As a result, the light-emitting section 10, the light-receiving section 20, and the control section 30 enclosed in the package 40 can quickly achieve uniform temperatures and maintain a steady temperature state. This enables the gas detection device 1 to output a highly stable detection signal.

[0057] The thermal insulation portion 70 is preferably formed from a material that has high thermal insulation properties and contains a large amount of gas or space relative to its material volume. Examples of such materials include air, porous materials, zeolite materials, foamed resins, glass wool, or fibrous materials such as ceramic fibers.

[0058] The thermal insulation portion 70 preferably has a thermal conductivity of 0.1 W / m·K or less. The lower the thermal conductivity of the thermal insulation portion 70, the greater the thermal resistance, which can improve the temperature uniformity effect. For example, the thermal conductivity of air is extremely low, at 0.0257 W / m·K at 20°C. In other words, since air has low thermal conductivity and is an inexpensive and easy-to-use material, it is most preferable to use air as the thermal insulation portion 70. Furthermore, from the viewpoint of further improving thermal insulation, it is preferable that the thermal conductivity of the thermal insulation portion 70 is lower than the thermal conductivity of the joint portion 60.

[0059] The thermal insulation portion 70 preferably has a thickness of 2 μm to 500 μm. The thicker the thermal insulation portion 70, the greater the thermal resistance and the greater the temperature uniformity effect. However, if the thermal insulation portion 70 is too thick, foreign matter such as dust can easily get mixed in, and its function will deteriorate. Therefore, by having a thickness within this range, the thermal insulation portion 70 can improve the temperature uniformity effect while preventing the incorporation of foreign matter.

[0060] For example, the thermal conductivity of epoxy resin is 0.3 W / m·K, while the thermal conductivity of air is 0.0257 W / m·K. The thermal conductivity of epoxy resin is an order of magnitude greater than that of air. Therefore, when epoxy resin is used for the thermal insulation part 70, the thickness of the thermal insulation part 70 can be increased by an order of magnitude compared to when air is used for the thermal insulation part 70.

[0061] As described above, it is preferable that the thermal insulation portion 70 has appropriate thermal conductivity, thickness, etc., depending on the material used. This can enhance the temperature uniformity effect.

[0062] At least a portion of the thermal insulation portion 70 is provided in a portion of the proximity region D. Preferably, the coverage of at least a portion of the thermal insulation portion 70 is 30% or more, and more preferably 50% or more and 90% or less. As shown in Figures 2A and 2B, the proximity region D is the region of the surface of the package 40 facing the light guide portion 50, and is the region where the distance between the package 40 and the light guide portion 50 is 500 μm or less. The coverage is the ratio of the area of ​​the thermal insulation portion 70 covering the proximity region D to the area of ​​the proximity region D.

[0063] The greater the coverage of the thermal insulation portion 70, the greater the thermal resistance, which can enhance the temperature uniformity effect. On the other hand, the smaller the coverage of the thermal insulation portion 70, the less thermal resistance it has, but the ratio of the area of ​​the joint portion 60 covering the adjacent region D to the area of ​​the adjacent region D can be increased, thus increasing the bonding strength between the package 40 and the light guide portion 50. Therefore, it is preferable that the coverage rate is defined considering the balance between the temperature uniformity effect and the bonding strength. By ensuring that the coverage rate of the thermal insulation portion 70 meets this range, the temperature uniformity effect can be enhanced while appropriately maintaining the bonding strength between the package 40 and the light guide portion 50.

[0064] As described above, by providing the thermal insulation section 70 in the space between the package 40 and the light guide section 50, the thermal insulation between the package 40 and the light guide section 50 can be enhanced. As a result, even if a heat flow enters the gas detection device 1, the flow of the heat flow to the light guide section 50 can be effectively suppressed, and the temperature inside the package 40 can be quickly made uniform.

[0065] 〔substrate〕 The substrate 100 is used to mount and fix the gas detection device 1. The substrate 100 is, for example, a printed circuit board, a flexible printed circuit board, or a rigid-flexible circuit board.

[0066] The substrate 100 comprises metal wiring 101, a base material, resin, etc. The substrate 100 is electrically connected to the light-emitting unit 10, light-receiving unit 20, control unit 30, etc., which are enclosed in the package 40, via a lead frame 42.

[0067] The substrates include, for example, paper, glass cloth, polyimide film, PET film, and ceramics. The resins include, for example, phenolic resin, epoxy resin, polyimide resin, bismaleimidotriazine resin, fluororesin, and polyphenylene oxide resin.

[0068] In this embodiment, the gas detection device 1 has a gap S1 formed between the light guide portion 50 and the package 40 by a joint portion 60 or a protrusion X, and a thermal insulation portion 70a is provided in this gap S1. This improves the thermal insulation between the package 40 and the light guide portion 50, thereby suppressing the flow of heat flowing into the gas detection device 1 to the light guide portion 50 and quickly equalizing the temperature inside the package 40. As a result, the gas detection device 1 can output a highly stable detection signal even when miniaturized.

[0069] <Variation> Referring to Figure 3, an example of the configuration of a modified gas detection device 1A will be described.

[0070] The difference between the gas detection device 1A according to Modification 1 and the gas detection device 1 according to the present embodiment is that while the gas detection device 1 according to the present embodiment has a protrusion X on the package 40 side, the gas detection device 1A according to Modification 1 has a protrusion Y on the light guide 50 side. Note that the other configurations are the same as those of the gas detection device 1 according to the present embodiment, so redundant explanations are omitted.

[0071] The light guide portion 50 has a protrusion Y that contacts the package 40. Because the light guide portion 50 has a protrusion Y that contacts the package 40, even if the thickness of the joint portion 60 becomes too thin during the mass production process, for example, a gap S1 can be formed between the package 40 and the light guide portion 50, and the distance between the package 40 and the light guide portion 50 can be maintained at a certain distance (for example, about 2 μm to 5 μm). Therefore, by providing a thermal insulating portion 70a in this gap S1, the thermal insulation between the package 40 and the light guide portion 50 can be improved.

[0072] The protrusion Y may be intentionally manufactured, but it may also be, for example, an unintentionally formed burr. By utilizing a burr as the protrusion Y, a special manufacturing process for forming the protrusion Y becomes unnecessary, and a gap S1 can be easily formed between the package 40 and the light guide 50.

[0073] In the modified gas detection device 1A, a gap S1 is formed between the light guide portion 50 and the package 40 by a joint portion 60 or a protrusion Y, and a thermal insulation portion 70a is provided in this gap S1. This improves the thermal insulation between the package 40 and the light guide portion 50, thereby suppressing the flow of heat flowing into the gas detection device 1A to the light guide portion 50, and allowing the temperature inside the package 40 to be quickly made uniform. As a result, the gas detection device 1A can output a highly stable detection signal even when miniaturized.

[0074] Although the embodiments described above are representative examples, it will be apparent to those skilled in the art that many modifications and substitutions are possible within the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited by the embodiments described above, and various modifications and changes are possible without departing from the scope of the claims. [Explanation of Symbols]

[0075] 1. Gas detection device 1A Gas detection device 1B Gas detection device 10 Light-emitting part 10B Light-emitting section 20 Light receiving section 20B Light receiving section 30 Control Unit 30B Control Unit 40 packages 40B Package 41 Metal wire 42 Lead Frames 50 Light guide section 50B Light guide part 51 Gasport 52 Dust Filter 60 Joint 70 Thermal insulation part 70a Thermal insulation 70b Thermal insulation 100 circuit boards 101 Metal wiring

Claims

1. A light-emitting unit that emits light in a wavelength band that includes the wavelength absorbed by the detected gas, A light-receiving unit having sensitivity in the aforementioned wavelength band, A package containing the light-emitting unit and the light-receiving unit, A light guide unit that guides the aforementioned light to the light receiving unit, A joint that joins the package and the light guide portion, A thermal insulating portion provided on the surface of the package and in the gap between the package and the light guide portion, Equipped with, A portion of the surface of the package facing the light guide portion has a proximity region where the distance between the package and the light guide portion is 500 μm or less. A gas detection device is provided adjacent to a portion of the adjacent region, with at least a part of the thermal insulation portion and at least a part of the joint portion.

2. The thermal insulation portion has a thermal conductivity of 0.1 W / m·K or less. The gas detection device according to claim 1.

3. The thermal insulation portion has a thickness of 2 μm or more and 500 μm or less. The gas detection device according to claim 1 or 2.

4. The coverage ratio, which is the ratio of the area of ​​the thermal insulating part covering the adjacent region to the area of ​​the adjacent region, is 30% or more. The gas detection device according to claim 1.

5. The aforementioned package has a metal component content of 25% or more. A gas detection device according to any one of claims 1 to 4.

6. The package has a protrusion that contacts the light guide portion, A gas detection device according to any one of claims 1 to 5.

7. The light guide portion has a protrusion that contacts the package. A gas detection device according to any one of claims 1 to 5.

8. The aforementioned thermal insulation part is a gas. A gas detection device according to any one of claims 1 to 7.

9. The system further comprises a control unit that controls the light-emitting unit and the light-receiving unit, The package contains the control unit, A gas detection device according to any one of claims 1 to 8.

10. The thermal conductivity of the thermal insulation portion is lower than that of the joint portion. A gas detection device according to any one of claims 1 to 9.

11. The light guide unit has a gas port for introducing the gas to be detected. A gas detection device according to any one of claims 1 to 10.

12. The thermal insulating portion is arranged around the light-emitting portion and the light-receiving portion, A gas detection device according to any one of claims 1 to 11.

Images