Infrared sensor module

Abstract

[Project] An infrared sensor module capable of small, high-precision infrared detection is provided. [Solution] An infrared sensor module (10) comprises a quantum infrared sensor (11) that detects light in the infrared region, a signal processing unit (21) that is electrically connected to the quantum infrared sensor, a heat conducting unit (15) that is in contact with the signal processing unit and is positioned at a different location from the quantum infrared sensor when viewed in a planar view, and a sealing unit (14) that integrally seals the quantum infrared sensor, the signal processing unit, and the heat conducting unit. A portion of the light receiving surface of the quantum infrared sensor and the heat conducting unit is exposed from the sealing unit, and the heat conducting unit is composed of a material having a higher thermal conductivity than resin.

Description

Technology Field

[0001] [Cross-reference of related applications]

[0002] This application claims priority to Japanese Patent Application No. 2023-050573 (filed March 27, 2023), and the entire disclosure of said application is incorporated herein by reference.

[0003] [Technology Field]

[0004] The present disclosure relates to an infrared sensor module. Background Technology

[0005] Generally, infrared sensors are used for various purposes, such as non-contact detection of the surface temperature of an object, detection of the presence of an object, and measurement of gas concentration in the atmosphere. For example, in order to accurately detect the surface temperature non-contactually, it is important to limit the field of view of the infrared sensor so as not to receive infrared radiation emitted from objects other than the object being measured. For example, Patent Document 1 discloses an infrared sensor having a field of view limiting portion formed in a reverse taper shape that widens from the position of entry of the infrared radiation toward the receiving surface, in a sealing resin. Prior art literature

[0006] Japanese Patent Publication No. 2015-083995 The problem to be solved

[0007] Here, in the detection of infrared radiation by an infrared sensor, thermal isolation from the outside is important, and thermal coupling with an optical component used together (e.g., a field of view limiting member, etc.) is important to reduce the effect of radiation. In addition, the infrared sensor may be provided as an infrared sensor module integrated with a signal processing unit that processes the detection signal to calculate a measurement value (e.g., the surface temperature of an object, gas concentration, etc.). Patent Document 1 does not disclose the configuration of an infrared sensor integrated with a signal processing unit.

[0008] In infrared sensor modules, thermal coupling with optical components used together with the infrared sensor is also important. Conventionally, as shown in FIG. 3, for example, a configuration is used in which a metal layer is provided on a substrate to surround a viewing limiting portion when viewed in a planar manner, thereby increasing the thermal conductivity between the infrared sensor and the optical component. However, in the conventional configuration, it is necessary to bring the optical component (the viewing limiting portion in FIG. 3) and the metal layer into contact on the outside of a large signal processing unit, making it difficult to miniaturize the infrared sensor module.

[0009] In light of these circumstances, the objective of the present disclosure is to provide an infrared sensor module capable of infrared detection that is compact and high-precision. means of solving the problem

[0010] (1) An infrared sensor module according to one embodiment of the present disclosure is,

[0011] A quantum infrared sensor that detects light in the infrared region, and

[0012] A signal processing unit electrically connected to the above-mentioned quantum infrared sensor, and

[0013] A thermal conductor that contacts the signal processing unit and is positioned at a different location from the quantum infrared sensor when viewed in a planar view, and

[0014] The above quantum infrared sensor, the above signal processing unit, and the above heat conduction unit are provided with a sealing unit that integrally seals the above quantum infrared sensor, the above signal processing unit, and the above heat conduction unit.

[0015] A portion of the light-receiving surface of the above-mentioned quantum infrared sensor and the heat-conducting portion is exposed from the sealing portion, and

[0016] The above-mentioned heat-conducting part is composed of a material with a higher thermal conductivity than resin.

[0017] (2) As one embodiment of the present disclosure, in (1),

[0018] It has an optical member disposed in contact with a portion of the heat conduction part exposed from the sealing part.

[0019] (3) As one embodiment of the present disclosure, in (2),

[0020] The above optical member is a field of view limiting part that limits the field of view of the light-receiving surface.

[0021] (4) As an embodiment of the present disclosure, in any one of (1) to (3),

[0022] The above signal processing unit and the above thermal conductor have a thermal expansion coefficient of 2×10 -6 / K to 10×10 -6 / K is.

[0023] (5) As one embodiment of the present disclosure, in any one of (1) to (4),

[0024] The above quantum infrared sensor and the above heat conduction part are placed on the main surface of the above signal processing part.

[0025] (6) As one embodiment of the present disclosure, in any one of (1) to (5),

[0026] The light-receiving surface of the above-mentioned quantum infrared sensor and a part of the above-mentioned heat-conducting portion are exposed from the same surface of the above-mentioned sealing portion. Effects of the invention

[0027] According to the present disclosure, an infrared sensor module capable of detecting infrared rays with high precision and being compact can be provided. Brief explanation of the drawing

[0028] FIG. 1 is a drawing showing an example of the configuration of an infrared sensor module according to one embodiment of the present disclosure. Figure 2 is a diagram showing an example of the configuration of an infrared sensor module having a field of view limiting part. Figure 3 is a diagram illustrating a conventional configuration of an infrared sensor module. Specific details for implementing the invention

[0029] Hereinafter, an infrared sensor module according to one embodiment of the present disclosure is described with reference to the drawings. In each drawing, identical or equivalent parts are given the same reference numerals. In the description of the present embodiment, the description of identical or equivalent parts is appropriately omitted or simplified.

[0030] (Infrared sensor module)

[0031] FIG. 1 shows the configuration of an infrared sensor module (10) according to the present embodiment. The infrared sensor module (10) comprises a quantum infrared sensor (11), a signal processing unit (21), a heat conduction unit (15), and a sealing unit (14). FIG. 1 is a cross-sectional view showing a cross- section of the infrared sensor module (10) including these components. Details of the components will be described later. In the present embodiment, the infrared sensor module (10) further comprises a substrate (12). The substrate (12) may be, for example, a rewiring substrate that connects the input / output of the signal processing unit (21) to the input / output of a package. The substrate (12) may be formed of, for example, Si or GaAs.

[0032] In this embodiment, the infrared sensor module (10) is used as a component of a non-contact temperature measuring device that measures the temperature of a target without contact. The infrared sensor module (10) detects the amount of energy (infrared radiation) of infrared radiation incident from the target using a quantum infrared sensor (11), and the signal processing unit (21) calculates the temperature of the target based on the detected amount of infrared radiation. Here, the infrared sensor module (10) is not limited to use in a specific application. As another example, the infrared sensor module (10) may be used as a component of a gas sensor of the NDIR (Non-Dispersive InfraRed) type that measures the concentration of gases such as carbon dioxide. The NDIR type gas sensor measures the concentration of the gas to be detected by detecting the amount of absorbed infrared radiation by utilizing the fact that the wavelength of infrared radiation absorbed varies depending on the type of gas. Additionally, the infrared sensor module (10) may be used, for example, in a moisture meter, a flame detector, etc.

[0033] (Quantum infrared sensor)

[0034] A quantum infrared sensor (11) is a sensor that detects light (infrared) in the infrared region by utilizing electrons or holes generated by photons when infrared light is irradiated onto a semiconductor. Compared to a thermal infrared sensor, the quantum infrared sensor (11) has high sensitivity and a fast response speed. The quantum infrared sensor (11) outputs a signal according to the amount of infrared light received. The output signal may be, for example, a current value. The light reception wavelength of the quantum infrared sensor (11) may be 2 μm to 12 μm. To enable further miniaturization, a quantum infrared sensor (11) containing materials such as InSb, InGaAs, InAs, AlInSb, or InAsSb may be used, but the material of the quantum infrared sensor (11) is not limited to a specific one. However, the quantum infrared sensor (11) preferably has a diode structure comprising at least one of indium and gallium and at least one of arsenic and antimony as materials, and at least two types of layers, a P-type semiconductor and an N-type semiconductor.

[0035] (Signal processing unit)

[0036] The signal processing unit (21) acquires a signal based on the amount of infrared radiation detected by the quantum infrared sensor (11) and calculates the temperature of the measurement target. Additionally, the signal processing unit (21) may control the timing of detection by the quantum infrared sensor (11). The signal processing unit (21) may include at least one of a general-purpose processor that executes functions according to a program read, and a dedicated processor specialized for specific processing. The dedicated processor may include an Application Specific Integrated Circuit (ASIC).

[0037] In this embodiment, the signal processing unit (21) is composed of an ASIC and is larger in size than the quantum infrared sensor (11). Additionally, the signal processing unit (21) is electrically connected to the quantum infrared sensor (11). That is, the signal processing unit (21) is connected to the quantum infrared sensor (11) by metal wiring. The method of connection is not limited to a specific type, and, for example, a lead frame may be used. There is a high thermal conductivity between the signal processing unit (21) and the quantum infrared sensor (11).

[0038] (Sealed part)

[0039] The sealing part (14) is composed of a resin material and integrally seals the quantum infrared sensor (11), the signal processing part (21), and the heat conduction part (15). The sealing part (14) may be formed from a resin material, such as epoxy resin, for example. The material constituting the sealing part (14) may include, in addition to the resin material such as epoxy resin, fillers, and inevitably mixed impurities. For example, silica is suitably used as a filler. The resin of the sealing part (14) has a low thermal conductivity of about 0.3 to 4 W / m·K, so that the quantum infrared sensor (11) can be thermally isolated from the space outside the infrared sensor module (10). In the configuration example of the quantum infrared sensor (11) shown in FIG. 1, the substrate (12) also uses a material with low thermal conductivity, thereby further enhancing the effect of thermally isolating the quantum infrared sensor (11) from the outside. Here, a portion of the light-receiving surface (13) and the heat-conducting portion (15) of the quantum infrared sensor (11) is exposed from the sealing portion (14). In the example of FIG. 1, a portion of the light-receiving surface (13) and the heat-conducting portion (15) is exposed from the same surface (top surface) of the sealing portion (14).

[0040] (Heat conduction part)

[0041] The thermal conductive part (15) is composed of a material with a higher thermal conductivity than resin. The thermal conductive part (15) may be composed of a metal, such as aluminum, which has a high thermal conductivity of about 200 W / m·K, a metal-plated resin, or a semiconductor material, such as Si, which has a thermal conductivity of about 150 W / m·K. In addition, the thermal conductive part (15) may be an integrated circuit different from the signal processing part (21), such as a memory chip. Furthermore, the quantum infrared sensor (11) may be shared with the thermal conductive part (15), that is, the quantum infrared sensor (11) may function as the thermal conductive part (15). In addition, the thermal conductive part (15) is positioned in contact with the signal processing part (21). Therefore, as indicated by the arrow in FIG. 1, a path with high thermal conductivity is formed. Here, the contact between the heat conduction part (15) and the signal processing part (21) includes not only direct contact but also a state in which heat conduction is not hindered by placing a heat-transmitting member between them. That is, the contact includes, for example, physical (direct) contact between the heat conduction part (15) and the signal processing part (21), as well as contact through, for example, an adhesive or grease. Furthermore, to ensure the stability of the joint, it is desirable that the thermal expansion coefficients of the heat conduction part (15) and the signal processing part (21) be close, and in this regard, the materials of both are the same, for example, Si (thermal expansion coefficient (notation omitted hereinafter) 4×10 -6 / K) together, or GaAs(5.4×10 -6 It is suitable to be composed of materials with a thermal expansion coefficient close to that of Si or GaAs, for example, Si, GaAs, alumina (8×10⁻⁶). -6 / K), silicon carbide (4.8×10⁻⁶ -6 / K) etc. are desirable. For example, the signal processing unit (21) and the heat conduction unit (15) have a thermal expansion coefficient of 2×10 -6 / K to 10×10 -6 / K. Also, as shown in FIG. 1, the heat conduction part (15) is positioned at a different location from the quantum infrared sensor (11) when viewed in a planar view. Here, viewing in a planar view refers to viewing the infrared sensor module (10) from above in the stacking direction in which the signal processing part (21), the heat conduction part (15), etc. are stacked on the substrate (12).

[0042] Here, the infrared sensor module (10) may be configured to further include an optical member (23) according to the application. In this embodiment, a field of view limiting member is used as the optical member (23) to prevent receiving infrared rays emitted from objects other than the object to be measured. The field of view limiting member limits the field of view of the light-receiving surface (13), particularly the field of view angle. FIG. 2 shows an example configuration of an infrared sensor module (10) having a field of view limiting member. The field of view limiting member is composed of a material that does not transmit infrared rays (e.g., resin or metal) and has an opening (22) formed in a tapered shape in a portion of the light-receiving surface (13). Additionally, for example, when the infrared sensor module (10) is used as a component of an NDIR type gas sensor, the optical member (23) may be a mirror, a lens, an optical filter, etc. As described above, thermal coupling with the optical member (23) is important for the quantum type infrared sensor (11) to detect infrared rays with high precision. In the configuration of the infrared sensor module (10) according to the present embodiment, a path with high thermal conductivity is formed through the heat conduction section (15) and the signal processing section (21). Therefore, by placing the optical member (23) in contact with a part of the heat conduction section (15) exposed from the sealing section (14), the quantum infrared sensor (11) and the optical member (23) can be thermally coupled. Here, the contact between the optical member (23) and the heat conduction section (15) includes not only direct contact but also a state in which heat conduction is not hindered by placing a heat-transmitting member between them. That is, the contact includes, for example, physical (direct) contact between the optical member (23) and the heat conduction section (15), as well as contact through, for example, an adhesive or grease. In addition, the optical member (23) and the heat conduction member (15) coming into contact includes a protective layer formed on the exposed portion of the heat conduction member (15) that does not impede heat conduction, and being connected through the protective layer.

[0043] For example, if the infrared sensor module (10) does not have a heat conduction part (15), the resin of the sealing part (14) is placed in the area where the heat conduction part (15) is shown in FIG. 2. In this case, a path with high thermal conductivity is not formed, and radiation occurs at the contact surface between the sealing part (14) and the optical member (23). Due to the influence of radiation, the quantum infrared sensor (11) receives infrared radiation emitted from objects other than the object to be measured, and thus the measurement precision is reduced. The infrared sensor module (10) according to the present embodiment is not affected by such radiation, so high-precision infrared detection is possible.

[0044] In addition, in the infrared sensor module (10) according to the present embodiment, it is possible to arrange the optical member (23) so as to be laminated on the sealing portion (14). Therefore, as in the conventional configuration of FIG. 3, there is no need to bring the optical member (23) and the metal layer into contact on the outside of the signal processing portion (21). Thus, the infrared sensor module (10) according to the present embodiment can be miniaturized. In particular, as shown in FIG. 2, by configuring the quantum infrared sensor (11) and the heat conduction portion (15) to be placed on the main surface (24) of the signal processing portion (21), it is possible to reduce the size in the width direction (left-right direction), thereby increasing the effect of miniaturization. Here, the main surface (24) is the surface with the largest area among the surfaces of the signal processing portion (21) and is the surface farther from the substrate (12).

[0045] As described above, the infrared sensor module (10) according to the present embodiment is capable of small and high-precision infrared detection by the above configuration.

[0046] Although embodiments of the present disclosure have been described based on various drawings and examples, those skilled in the art should note that it is easy to make various modifications or variations based on the present disclosure. Accordingly, it should be noted that such modifications or variations are included within the scope of the present disclosure. Explanation of the symbols

[0047] 10: Infrared sensor module 11: Quantum infrared sensor 12: Substrate 13: Sugwang-myeon 14: Sealing part 15: Heat conduction part 21: Signal processing unit 22: Opening 23: Optical component 24: If you give

Claims

Claim 1 An infrared sensor module comprising: a quantum infrared sensor for detecting light in the infrared region; a signal processing unit electrically connected to the quantum infrared sensor; a heat conducting unit in contact with the signal processing unit and positioned at a different location from the quantum infrared sensor when viewed in a plane; a sealing unit that integrally seals the quantum infrared sensor, the signal processing unit, and the heat conducting unit; and an optical member positioned in contact with a portion of the heat conducting unit exposed from the sealing unit, wherein the light receiving surface of the quantum infrared sensor and a portion of the heat conducting unit are exposed from the sealing unit, the heat conducting unit is composed of a material having a higher thermal conductivity than resin, and the quantum infrared sensor and the heat conducting unit are positioned on the main surface of the signal processing unit. Claim 2 delete Claim 3 In claim 1, the optical member is an infrared sensor module that is a field of view limiting part that limits the field of view of the light-receiving surface. Claim 4 In claim 1, the signal processing unit and the heat conducting unit have a thermal expansion coefficient of 2×10 -6 / K to 10×10 -6 / K, infrared sensor module. Claim 5 delete Claim 6 In claim 1, the infrared sensor module wherein the light-receiving surface of the quantum infrared sensor and a part of the heat-conducting portion are exposed from the same surface of the sealing portion.

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