Physical quantity measuring device and method for manufacturing a physical quantity measuring device
The device addresses miniaturization and integration challenges by using through-holes in the optical component and circuit board to enable rapid air exchange, improving measurement response speed and accuracy.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- ASAHI KASEI MICRODEVICES CORP
- Filing Date
- 2024-12-26
- Publication Date
- 2026-07-08
AI Technical Summary
Existing physical quantity measuring devices, such as gas sensors, face challenges in miniaturization and integration with other electronic components, leading to delayed measurement response and inaccurate readings due to air replacement difficulties and wind pressure issues.
A physical quantity measuring device with an optical component and circuit board through-holes that allow air to bypass the circuit board, ensuring rapid air exchange without obstructing light paths, enabling high integration and improved measurement response.
The device achieves both high integration and rapid response speed by facilitating air exchange around the sensor, enhancing measurement accuracy and responsiveness.
Smart Images
Figure 2026114794000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a physical quantity measuring device and a method for manufacturing the physical quantity measuring device.
Background Art
[0002] Physical quantity measuring devices for measuring the physical quantity of a measurement object are used in various fields. As an example of a physical quantity measuring device, a gas sensor for detecting the concentration of a detected gas can be mentioned. With the progress of semiconductor technology and MEMS technology, the miniaturization of gas sensors has advanced, and their mounting into the housings of various electronic devices has been promoted (for example, see Patent Document 1).
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] The device disclosed in Patent Document 1 may include a detector that detects the presence of carbon monoxide gas and issues an alarm when it determines that the level of carbon monoxide gas is high. When the concentration of the detected gas increases or decreases in the space where the sensor unit is arranged, it is desirable for the gas sensor to output a measurement value following the increase or decrease in this concentration as quickly as possible.
[0005] Here, there is a demand for further miniaturization of electronic devices, and when the integration degree of other surrounding electronic components or other environmental sensors is high, the replacement of air around the gas sensor is likely to be difficult. As a result, the measurement response may be delayed. Also, for example, when wind blows towards the gas sensor, if there is no escape route for the wind, the pressure of the gas near the gas sensor increases and accurate measurement becomes difficult.
[0006] In view of these circumstances, the purpose of this disclosure is to provide a physical quantity measuring device and a method for manufacturing a physical quantity measuring device that can achieve both high integration and improved response speed of physical quantity measurement. [Means for solving the problem]
[0007] (1) A physical quantity measuring device according to one embodiment of the present disclosure is: An optical component having a surface on which at least a mirror is formed, The optical component comprises a circuit board that is at least partially bonded to it, The optical component has a first through-hole when viewed from above, The circuit board has a second through-hole when viewed from above, The first through-hole and the second through-hole overlap, at least partially, when viewed from above.
[0008] (2) As one embodiment of the present disclosure, in (1), The circuit board has a light-emitting element on the side facing the optical component. The optical component guides the light emitted from the light-emitting element, The first and second through holes are provided such that, when viewed from above, they do not overlap with the path through which the light is guided by the optical component.
[0009] (3) In one embodiment of the present disclosure, in (1) or (2), The first through-hole and the second through-hole enclose the other when viewed from above.
[0010] (4) In one embodiment of the present disclosure, in any of (1) to (3), The diameter of the second through hole is larger than the diameter of the first through hole.
[0011] (5) In one embodiment of the present disclosure, in any of (1) to (4), The diameters of the first through-hole and the second through-hole are within the range of 1 mm to 5 mm.
[0012] (6) As one embodiment of the present disclosure, in any one of (1) to (3), The first through-hole and the second through-hole are polygonal or cross-shaped in a top view.
[0013] (7) As one embodiment of the present disclosure, in any one of (1) to (6), The optical component has a ventilation hole for taking in gas into the gas detection space, The first through-hole is not connected to the gas detection space.
[0014] (8) As one embodiment of the present disclosure, in any one of (1) to (7), The optical component has a ventilation hole for taking in gas into the gas detection space, The diameter of the first through-hole and the opening area of the second through-hole are larger than the opening area of the ventilation hole.
[0015] (9) A method for manufacturing a physical quantity measuring device according to an embodiment of the present disclosure is A method for manufacturing a physical quantity measuring device including an optical component having a surface on which at least a part of a mirror is formed and a circuit board that is at least partially joined to the optical component, The optical component has a first through-hole in a top view, The circuit board has a second through-hole in a top view, The method includes a step of joining the optical component and the circuit board such that the first through-hole and the second through-hole at least partially overlap each other in a top view.
Advantages of the Invention
[0016] According to the present disclosure, it is possible to provide a physical quantity measuring device and a method for manufacturing a physical quantity measuring device that enable both high integration and an improvement in the response speed of physical quantity measurement.
Brief Description of the Drawings
[0017] [Figure 1] FIG. 1 is a diagram showing a configuration example of a physical quantity measuring device according to the present embodiment. [Figure 2] FIG. 2 is a perspective view of the physical quantity measuring device of FIG. 1. [Figure 3] FIG. 3 is a diagram showing the configuration of the physical quantity measuring device of the comparative example.
Embodiments for Carrying Out the Invention
[0018] Hereinafter, a physical quantity measuring device 20 (see FIG. 1) according to an embodiment of the present disclosure and a method for manufacturing the physical quantity measuring device 20 will be described with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals. In the description of this embodiment, the description of the same or corresponding parts will be omitted or simplified as appropriate.
[0019] FIG. 1 is a cross-sectional view showing a configuration example of the physical quantity measuring device 20 according to this embodiment. Further, FIG. 2 is a perspective view of a portion including the optical component 40 of the physical quantity measuring device 20 of FIG. 1. The physical quantity measuring device 20 measures the physical quantity of the measurement object. The physical quantity measuring device 20 according to this embodiment will be described as a gas sensor that measures the measurement object as air and the physical quantity as the concentration of the detected gas in the air. However, the measurement object and the physical quantity are not limited to specific ones. Here, the detected gas is, for example, carbon dioxide, water vapor, carbon monoxide, nitric oxide, ammonia, sulfur dioxide, alcohol, formaldehyde, and hydrocarbon gases such as methane and propane.
[0020] As shown in Figure 1, the physical quantity measuring device 20 according to this embodiment constitutes an electronic device together with other components 50. In this embodiment, the electronic device has at least a gas detection function and may be, for example, an alcohol detector, an air purifier, a gas alarm, etc., but is not limited to any specific one. The other components 50 are components of the electronic device other than the physical quantity measuring device 20. The other components 50 may include one or more processors that control the entire electronic device. The processor may, for example, perform calculation processing on the measurement value measured by the optical component 40 to calculate the concentration of the gas to be detected. The other components 50 may also include sensors that detect gases other than the gas to be detected. In the example in Figure 1, the other components 50 are mounted on the circuit board 30 together with the physical quantity measuring device 20, but the configuration is not limited to this. For example, there may be a main board different from the circuit board 30, and the physical quantity measuring device 20 and the other components 50 may be mounted on the main board.
[0021] Furthermore, as shown in Figure 1, the electronic device has a housing 10, and a physical quantity measuring device 20 is arranged inside the housing 10 together with other components 50. The housing 10 is provided with two ventilation openings 19 through which air, which is the object to be measured, enters and exits. The housing 10 may be made of metal, glass, resin, or a composite material thereof.
[0022] The physical quantity measuring device 20 according to this embodiment comprises an optical component 40 having a surface on which at least a mirror is formed, and a circuit board 30 that is at least partially bonded to the optical component 40. As shown in Figure 1, the optical component 40 is placed on the surface of the circuit board 30, with one of the surfaces with the largest area (main surface) being the front surface and the other being the back surface. In the following description, viewing the surface of the circuit board 30 from the optical component 40 (viewed in the direction of arrow V in Figure 1) will be referred to as "top view".
[0023] In this embodiment, the optical component 40 functions as the gas measuring unit of an NDIR (Non-Dispersive InfraRed) type gas sensor. The NDIR type gas sensor measures the concentration of the detected gas using a light-receiving element 12 that receives infrared light in the absorption wavelength band corresponding to the gas to be detected, and a light-emitting element 11 that emits infrared light in the same absorption wavelength band. The light-emitting element 11 is, for example, an LED (Light Emitting Diode). The light-receiving element 12 is, for example, a photodiode.
[0024] The circuit board 30 has a light-emitting element 11 on the side facing the optical component 40. The circuit board 30 also has a light-receiving element 12 on the side facing the optical component 40. In this embodiment, the optical component 40 has a reflective portion 17 that reflects light 18 (infrared rays) emitted from the light-emitting element 11 and directs it into the light-receiving element 12. In other words, the reflective portion 17 corresponds to the "surface on which the mirror is formed". In the example in Figure 1, the reflective portion 17 is a concave mirror. The reflective surface of the reflective portion 17 may be made of a metal with high reflectivity, such as aluminum or gold. The optical component 40 also has a gas detection space 42 as an internal space, which is provided with ventilation holes 43. Gas (air in this embodiment) is drawn into the gas detection space 42 through the ventilation holes 43. The optical component 40 uses a reflector 17 to guide light 18 emitted from the light-emitting element 11 through the gas detection space 42 to the light-receiving element 12, so that the concentration of the gas to be detected in the air taken into the gas detection space 42 can be measured.
[0025] In recent years, electronic devices have been required to be even smaller, making it difficult for the air around the gas sensor to be replaced. For example, Figure 3 shows the configuration of a conventional physical quantity measuring device 120, which is a comparative example. When the physical quantity measuring device 120 is placed inside the housing 10, a circuit board 30 is located between one and the other of the ventilation section 19. As a result, air entering from one side of the ventilation section 19 flows around the circuit board 30 to the other side of the ventilation section 19. In other words, it is difficult for the air around the gas sensor to be replaced. Consequently, when the concentration of the gas to be detected in the air changes, it takes time for the changed air to be taken into the gas detection space 42, resulting in a slower measurement response. Also, for example, if wind blows in from one side of the ventilation section 19, the air does not pass through easily, causing the pressure of the gas near the gas sensor to rise, making accurate measurement difficult.
[0026] To address the issue of slow response speed, the physical quantity measuring device 20 according to this embodiment has a first through-hole 41 and a second through-hole 31. The optical component 40 has the first through-hole 41 when viewed from above. The circuit board 30 also has the second through-hole 31 when viewed from above. As shown in Figures 1 and 2, when viewed from above, one of the first through-hole 41 and the second through-hole 31 overlaps with the other at least partially. Because the physical quantity measuring device 20 has the first through-hole 41 and the second through-hole 31, air entering from one side of the ventilation section 19 passes through the first through-hole 41 and the second through-hole 31 and reaches the other side of the ventilation section 19 without having to bypass the circuit board 30. Therefore, the physical quantity measuring device 20 according to this embodiment enables both high integration (miniaturization of electronic devices) and improved response speed of physical quantity measurement. Here, the height of the first through-hole 41 (length in the direction of arrow V in Figure 1) may be less than the maximum height of the gas detection space 42, and may be less than half the maximum height of the gas detection space 42.
[0027] Furthermore, the first through-hole 41 and the second through-hole 31 may be provided so as not to overlap with the path through which the light 18 is guided by the optical component 40 when viewed from above. In other words, the first through-hole 41 is provided separately from the ventilation hole 43 in the optical component 40, and the first through-hole 41 is not connected to the gas detection space 42. With this configuration, it is possible to easily replace the air around the gas sensor without affecting the measurement of the concentration of the gas to be detected.
[0028] The first through-hole 41 and the second through-hole 31 may be configured such that one encloses the other when viewed from above. For example, the diameter of the second through-hole 31 may be larger than the diameter of the first through-hole 41. For example, the second through-hole 31 may be formed by machining the circuit board 30 using a drill or the like. The first through-hole 41 and the second through-hole 31 may also serve as holes for aligning the optical component 40 and the circuit board 30. For example, alignment may be performed by inserting tapered pins into the second through-hole 31 and the first through-hole 41 from the back side of the circuit board 30. The material of the circuit board 30 may be, for example, resin, glass cloth, or ceramics. Examples of resins include phenolic resin, epoxy resin, polyimide resin, bismaleimide triazine resin, fluororesin, and polyphenylene oxide resin.
[0029] Furthermore, the diameters of the first through-hole 41 and the second through-hole 31 may be within the range of 1 mm to 5 mm. Here, the first through-hole 41 and the second through-hole 31 are not limited to being circular in top view, but may be polygonal or cross-shaped in top view, for example.
[0030] Furthermore, when viewed from above, the diameter of the first through-hole 41 and the opening area of the second through-hole 31 may be larger than the opening area of the ventilation hole 43. By doing so, the exchange of gas near the gas sensor can be accelerated in relation to the exchange of gas in the gas detection space 42, thereby enhancing the effects of having the first through-hole 41 and the second through-hole 31.
[0031] Furthermore, the optical component 40 has a third through-hole when viewed from above, and the circuit board 30 has a fourth through-hole when viewed from above, and the third and fourth through-holes may at least partially overlap with the other when viewed from above. By having multiple sets of through-holes similar to the first through-hole 41 and the second through-hole 31, it is possible to further facilitate the exchange of air around the gas sensor. Moreover, when these through-holes are used as holes for aligning the optical component 40 and the circuit board 30, more accurate alignment can be achieved.
[0032] Furthermore, the manufacturing method of the physical quantity measuring device 20 may include a step of joining the optical component 40 and the circuit board 30 such that, when viewed from above, one of the first through hole 41 and the second through hole 31 at least partially overlaps with the other.
[0033] As described above, the physical quantity measuring device 20 and the method for manufacturing the physical quantity measuring device 20 according to this embodiment enable rapid replacement of the surrounding air, thereby achieving both high integration and improved response speed of physical quantity measurement.
[0034] While embodiments of this disclosure have been described based on the drawings and examples, it should be noted that those skilled in the art will find it easy to make various modifications or alterations based on this disclosure. Therefore, it should be noted that these modifications or alterations are included within the scope of this disclosure. [Explanation of symbols]
[0035] 10 cabinets 11 Light-emitting element 12. Photodetector 17 Reflector 18 light 19 Ventilation section 20 Physical quantity measuring device 30 Circuit boards 31 Second through hole 40 Optical Components 41 First through hole 42 Gas detection space 43 Ventilation holes 50 Other parts 120 Physical Quantity Measuring Device
Claims
1. An optical component having a surface on which at least a mirror is formed, The optical component comprises a circuit board that is at least partially bonded to it, The optical component has a first through-hole when viewed from above, The circuit board has a second through-hole when viewed from above, A physical quantity measuring device wherein the first through-hole and the second through-hole overlap, at least partially, when viewed from above.
2. The circuit board has a light-emitting element on the side facing the optical component. The optical component guides the light emitted from the light-emitting element, The physical quantity measuring device according to claim 1, wherein the first through hole and the second through hole are provided such that, when viewed from above, they do not overlap with the path through which the light is guided by the optical component.
3. The physical quantity measuring device according to claim 1 or 2, wherein the first through hole and the second through hole enclose the other when viewed from above.
4. The physical quantity measuring device according to claim 1 or 2, wherein the diameter of the second through hole is larger than the diameter of the first through hole.
5. The physical quantity measuring device according to claim 1 or 2, wherein the diameter of the first through hole and the diameter of the second through hole are in the range of 1 mm to 5 mm.
6. The physical quantity measuring device according to claim 1 or 2, wherein the first through hole and the second through hole are polygonal or cross-shaped when viewed from above.
7. The optical component has a ventilation hole for introducing gas into the gas detection space. The physical quantity measuring device according to claim 1 or 2, wherein the first through-hole is not connected to the gas detection space.
8. The optical component has a ventilation hole for introducing gas into the gas detection space. The physical quantity measuring device according to claim 1 or 2, wherein the diameter of the first through-hole and the opening area of the second through-hole are greater than the opening area of the ventilation hole.
9. A method for manufacturing a physical quantity measuring device comprising an optical component having a surface on which at least a part of a mirror is formed, and a circuit board at least partially bonded to the optical component, The optical component has a first through-hole when viewed from above, The circuit board has a second through-hole when viewed from above, A method for manufacturing a physical quantity measuring device, comprising the step of joining the optical component and the circuit board such that, in a top view, one of the first through hole and the second through hole at least partially overlaps with the other.