SENSOR MODULE
Disclosed herein is a sensor module that includes a substrate having a top surface and a back surface, a sensor element mounted on the top surface of the substrate, an external terminal formed on the back surface of the substrate, and a case fixed to the substrate so as to cover the sensor element. The case has a top plate part having a plurality of through holes. The top plate part has a center area having no through holes and a through hole formation area having the plurality of through holes, the through hole formation area being positioned so as to surround the center area.
This is a Continuation of U.S. Pat. Application No. 17/360,063 filed on Jun. 28, 2021, which claims the benefit of Japanese Patent Application No. 2020-123506 filed on Jul. 20, 2020 including the specification, drawings and abstract are incorporated herein by reference in their entirety.
BACKGROUND OF THE INVENTION --Field of the InventionThe present invention relates to a sensor module and, more particularly, to a sensor module for detecting, e.g., a predetermined gas component contained in a measurement atmosphere.
--Description of Related ArtA gas sensor for detecting a predetermined gas component is described in Japanese Patent No. 4,280,705. The gas sensor described in Japanese Patent No. 4,280,705 includes a substrate having a cavity, a gas detection element housed in the cavity, and a protective cap covering the cavity. The protective cap has a plurality of vent holes, through which an external gas to be measured is introduced into the cavity.
In the gas sensor described in Japanese Patent No. 4,280,705, the protective cap has, at its top, a planar portion having no vent hole. With the planar portion sucked by a suction nozzle of a chip mounter, the gas sensor is surface-mounted on a circuit board.
However, in the gas sensor described in Japanese Patent No. 4,280,705, the planar portion of the protective cap is formed eccentric to the center position, so that when it is sucked by the chip mounter suction nozzle, the posture of the gas sensor may become unstable. Such a problem may occur not only in the gas sensor but also in all the sensor modules that are surface-mountable on a circuit board, including, for example, sensor modules for detecting vibration, pressure, and temperature of air, which are specifically microphones, pressure sensors, and temperature sensors.
SUMMARYIt is therefore an object of the present invention, in a sensor module surface-mountable on a circuit board, to make the posture of the sensor module more stable during a sucking process using the chip mounter suction nozzle while ensuring sufficient air circulation.
A sensor module according to the present invention includes: a substrate having a top surface and a back surface; a sensor element mounted on the top surface of the substrate; an external terminal formed on the back surface of the substrate; and a case covering the sensor element fixed to the substrate. The case has a top plate part having a plurality of through holes. The top plate part has a center area having no through holes and a through hole formation area positioned so as to surround the center area and having the plurality of through holes.
According to the present invention, no through holes are formed in the center area of the top plate part, so that the center area can be sucked by a suction nozzle of a chip mounter, allowing the sensor module to be surface-mounted on a circuit board with a stable posture.
In the present invention, the top plate part may have a rectangular outer shape. This can maximize the volume of a space surrounded by the case. In this case, the through hole formation area may include a clearance area having no through holes, and the clearance area may be positioned in the vicinity of the corner portion of the top plate part or in the vicinity of substantially the center portion of the side of the top plate part. With this configuration, when the top plate part needs to be held with a jig in an inspection process, the clearance area can be held with the jig, thus preventing the through holes from being closed by the jig.
The sensor module according to the present invention may further include a filter overlapping the plurality of through holes. This can prevent foreign matters from entering the space surrounded by the case. In this case, the filter may selectively cover the through hole formation area so as to overlap the plurality of through holes without covering the center area. This can prevent contact between the filters and the suction nozzle during the suction process using the chip mounter suction nozzle.
Further, the filter may be formed as a single member having a continuous shape. This simplifies a filter attachment process and can enhance attachment strength between the filter and the top plate part. In this case, the top plate part may include an attachment area covered with the filter and a non-attachment area not covered with the filter, and the attachment area may overlap the through hole formation area, and the non-attachment area may include the center area, an outside area positioned outside the through hole formation area, and a separation area overlapping the through hole formation area and connecting the center area and the outside area. With this configuration, in a process of removing an unnecessary part of a filter sheet that has been attached to the top plate part, the unnecessary part that has been attached to the outside area and the unnecessary part that has been attached to the center area can be removed in a single step.
As described above, according to the present invention, it is possible to make the posture of the sensor module more stable during a suction process using the chip mounter suction nozzle while ensuring sufficient air circulation.
The above features and advantages of the present invention will be more apparent from the following description of certain preferred embodiments taken in conjunction with the accompanying drawings, in which:
Preferred embodiments of the present invention will be explained below in detail with reference to the accompanying drawings.
First EmbodimentAs illustrated in
The sensor chip 20 has a sensor element for measuring the concentration of a predetermined gas component (CO2, etc.) contained in a measurement atmosphere. However, the sensor chip 20 may not necessarily be a gas sensor but may be a sensor for detecting vibration, pressure, temperature, humidity, or the like of the air in a measurement atmosphere, which is specifically, a microphone, a pressure sensor, a temperature sensor, a humidity sensor, or the like. In the example illustrated in
The control IC 30 is connected to the sensor chip 20 and has an integrated control circuit for calculating measurement values based on the output from the sensor chip 20. Although not particularly limited, the control IC 30 may be a semiconductor IC in a bare-chip state. The control IC 30 is also connected to the external terminals 13. Some external terminals 13 may be connected directly to the sensor chip 20. The sensor chip 20 and the control IC 30 may not necessarily be separated chips, and an IC including a sensor element and a control circuit in one chip may be used.
The case 40 is made of a material having sufficient strength, such as metal or resin, and includes a top plate part 41 facing the surface 11 of the substrate 10 and a side plate part 42 connected to the top plate part 41 and surrounds the sensor chip 20 and control IC 30 in a plan view (as viewed in the z-direction). The top plate part 41 is parallel to the surface 11 of the substrate 10 and constitutes the xy plane. The side plate part 42 is perpendicular to the surface 11 of the substrate 10 and constitutes the xz plane or yz plane. The top plate part 41 has a plurality of through holes 43. The through holes 43 allow air to circulate therethrough from outside to inside of the case 40. For example, when the sensor chip 20 is a gas sensor, a gas component to be measured enters the inside of the case 40 through the through holes 43 and is measured in concentration by the sensor chip 20. In the present embodiment, the through hole 43 has a circular planar shape, which minimizes a reduction in strength of the top plate part 41 due to the presence of the through holes 43.
As illustrated in
As illustrated in
As illustrated in
The jigs 51 to 54 are disposed so as to cover the corner portions of the top plate part 41 and their vicinities. The corner portions and their vicinities are comparatively higher in strength against a force in the z-direction, thus preventing the sensor module 1A from being deformed and damaged during the inspection process. Although the jigs 51 to 54 are disposed so as to partially cover the through hole formation area 41B, they are disposed so as to each overlap the clearance area so as not to close the through hole 43. This allows the inspection to be performed under the same conditions as in actual use.
Second EmbodimentThe sensor module 1B illustrated in
The sensor module 1C illustrated in
The sensor module 1D illustrated in
The sensor modules 2A to 2D illustrated in
The filters 61 to 64 are each a member for preventing entering of a predetermined gas component that may deteriorate the sensor element, dust, and dirt. In the sensor modules 2A and 2B illustrated in
The filters 61 to 64 can be attached as follows. A filter sheet having cuts along which the filters 61 to 64 can be separated one from another is attached to the top plate part 41, and an unnecessary part of the filter sheet is removed so as to leave the filters 61 to 64 on the top plate part 41. This method can reduce the number of processes as compared to when the filters 61 to 64 are individually attached.
Ninth and Tenth EmbodimentsThe sensor modules 3A and 3B illustrated in
As exemplified in the ninth and tenth embodiments, the filter to be attached to the top plate part 41 may be a signal member having a continuous shape. In this case, attachment strength between the top plate part 41 and the filter can be enhanced due to an increase in the attachment area. To further enhance the attachment strength, the filter may be attached to the entire inner surface (the surface of the top plate part 41 that faces the surface 11 of the substrate 10). The outer and inner shapes of the filter 65 are each not a quadrangle, but an octagon so as to sufficiently separate the filter 65 from the corner portions of the top plate part 41. This can prevent contact between the jigs 51 to 54 and the filter 65 during the inspection process illustrated in
The filter 65 can be attached as follows. A filter sheet having cuts is attached to the top plate part 41, and an unnecessary part of the filter sheet positioned in the center area 41A and an unnecessary part positioned in the outside area 41C are removed so as to leave the filter 65 on the top plate part 41.
Eleventh EmbodimentThe sensor module 3C illustrated in
The sensor module 3D illustrated in
The sensor module 3E illustrated in
The sensor module 4A illustrated in
First, as illustrated in
Then, as illustrated in
Thus, according to the sensor module 4A of the fourteenth embodiment, the removal process of the filter sheet 66 can be simplified. To prevent unintended peeling of the filter 65 during the removal process of the filter sheet 66, it is preferable to chamfer the edge portion of the filter 65 positioned at the boundary between the outside area 41C and the separation area 41D, as illustrated in
To facilitate the removal of the unnecessary part 66D, it is preferable to make the width of the separation area 41D wider from the center area 41A toward the outside area 41C, as illustrated in
The sensor module 4B illustrated in
To prevent unintended peeling of the filter 65 in the removal process of the filter sheet 66, it is preferable to chamfer the edge portion of the filter 65 positioned at the boundary between the outside area 41C and the separation area 41D, as illustrated in
To facilitate the removal of unnecessary part 66D, it is preferable to make the width of the separation area 41D wider from the center area 41A toward the outside area 41C, as illustrated in
The sensor module 4C illustrated in
It is apparent that the present invention is not limited to the above embodiments, but may be modified and changed without departing from the scope and spirit of the invention.
Claims
1. A sensor module comprising:
- a substrate having a top surface, the top surface having first and second regions;
- a first sensor chip mounted on the first region of the top surface of the substrate;
- a control IC mounted on the second region of the top surface of the substrate and electrically connected to the first sensor chip; and
- a case fixed to the substrate so as to cover the first sensor chip and the control IC,
- wherein the case has a plurality of through holes.
2. The sensor module as claimed in claim 1, wherein the plurality of through holes includes a first through hole that overlaps the first sensor chip.
3. The sensor module as claimed in claim 2, wherein the plurality of through holes further includes a second through hole that overlaps the control IC.
4. The sensor module as claimed in claim 3, further comprising a second sensor chip electrically connected to the control IC,
- wherein the top surface further has a third region on which the second sensor chip is mounted.
5. The sensor module as claimed in claim 4, wherein the plurality of through holes further includes a third through hole that overlaps the second sensor chip.
6. The sensor module as claimed in claim 5, wherein the plurality of through holes further includes a plurality of fourth through holes that do not overlap the first sensor chip, the second sensor chip, and the control IC.
7. The sensor module as claimed in claim 6,
- wherein the first and third through holes are arranged along a first virtual line extending in a first direction, and
- wherein the plurality of fourth through holes are arranged along a second virtual line extending in a second direction different from the first direction.
8. The sensor module as claimed in claim 7,
- wherein the plurality of through holes further includes a plurality of fifth through holes that do not overlap the first sensor chip, the second sensor chip, and the control IC, and
- wherein the plurality of fifth through holes are arranged along a third virtual line extending in parallel with the second virtual line.
9. The sensor module as claimed in claim 8,
- wherein the case has a center area positioned between the plurality of fourth through holes and the plurality of fifth through holes in the first direction, and
- wherein the center area of the case has no through hole.
10. The sensor module as claimed in claim 9, wherein the center area of the case is positioned between the first and third through holes and the second through hole in the second direction.
11. A sensor module comprising:
- a substrate having a top surface having a rectangular planar shape;
- a first sensor chip mounted on the top surface of the substrate;
- a case fixed to the substrate so as to cover the first sensor chip,
- wherein the case has: a plurality of first through holes arranged along a first virtual line extending in a first direction; a plurality of second through holes arranged along a second virtual line extending in parallel with the first virtual line; a plurality of third through holes arranged along a third virtual line substantially perpendicular to the first and second virtual lines; and a plurality of fourth through holes arranged along a fourth virtual line extending in parallel with the third virtual line, and
- wherein one of the plurality of first through holes overlaps the first sensor chip.
12. The sensor module as claimed in claim 11,
- wherein the case has a center area positioned between the plurality of first through holes and the plurality of second through holes in the second direction and positioned between the plurality of third through holes and the plurality of fourth through holes in the first direction, and
- wherein the center area of the case has no through hole.
13. The sensor module as claimed in claim 12,
- wherein the case further has: a first corner area at which the first and third virtual lines cross each other; a second corner area at which the first and fourth virtual lines cross each other; a third corner area at which the second and third virtual lines cross each other; and a fourth corner area at which the second and fourth virtual lines cross each other, and
- wherein the first, second, third, and fourth corner areas of the case have no through hole.
14. The sensor module as claimed in claim 11, further comprising a control IC mounted on the top surface of the substrate and electrically connected to the first sensor chip,
- wherein the covers the first sensor chip and the control IC.
15. The sensor module as claimed in claim 14, wherein at least one of the plurality of second through holes overlaps the control IC.
16. The sensor module as claimed in claim 15, wherein each of the plurality of second through holes overlaps the control IC.
17. The sensor module as claimed in claim 14, wherein the plurality of third through holes and the plurality of fourth through holes do not overlap the first sensor chip and the control IC.
18. The sensor module as claimed in claim 14, further comprising a second sensor chip mounted on the top surface of the substrate and electrically connected to the control IC,
- wherein another one of the plurality of first through holes overlap the second sensor chip.
Type: Application
Filed: May 26, 2023
Publication Date: Sep 21, 2023
Inventor: Kei TANABE (Tokyo)
Application Number: 18/324,482