Pressure sensor and electronic device

Abstract

The invention provides a pressure sensor which maintains waterproofness and suppresses poor installation to a housing. A pressure sensor according to the present disclosure includes a substrate, a detection element provided on the substrate and configured to detect pressure, and a cover member provided on the substrate. The cover member has an exposure hole that exposes at least a portion of the detection element to the outside, and covers the detection element with a portion other than the exposure hole. The cover member has: a main body having an upper surface on the side opposite to the surface facing the substrate; and a protruding portion protruding from an upper surface of the main body and provided with an exposure hole. The main body has one or more recessed portions that are provided on the upper surface along the protruding portion in a plan view as viewed from the thickness direction of the substrate and that are recessed in the thickness direction. The one or more recessed portions are provided in at least a portion of the protruding portion in the circumferential direction in a plan view.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a pressure sensor formed using a MEMS (Micro Electro Mechanical Systems) technique and an electronic device equipped with the pressure sensor. BACKGROUND

[0002] In the past, as such a pressure sensor, for example, a pressure sensor described in Patent Literature 1 has been known. The pressure sensor described in Patent Literature 1 is provided with a base member, a detection element provided on the base member, and a resin package provided on the base member in a manner of covering the detection element. An exposure hole that exposes at least a part of the detection element is provided in the resin package.

[0003] The resin package has a rectangular parallelepiped-shaped main body portion provided on the base member, and a columnar ring holding portion that extends from an upper surface of the main body portion in a direction away from the base member. The exposure hole is provided to be open at a top of the ring holding portion and extend toward the base member.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: U.S. Patent Application Publication No. 2022 / 0190230 Specification SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] In the pressure sensor of Patent Literature 1, there is room for improvement from the viewpoint of suppressing mounting failure of the pressure sensor to the housing while maintaining waterproofness.

[0009] Therefore, an object of the present disclosure is to solve the above problems, and to provide a pressure sensor that suppresses mounting failure to a housing while maintaining waterproofness.

[0010] SOLUTION TO PROBLEM

[0011] The pressure sensor of the present disclosure includes:

[0012] a substrate;

[0013] a detection element provided on the substrate for detecting pressure; and

[0014] a cover member provided on the substrate, having an exposure hole that exposes at least a part of the detection element to the outside, and covering the detection element with a portion other than the exposure hole,

[0015] The cover member includes:

[0016] a main body having an upper surface on a side opposite to a side on which a surface facing the substrate is located; and

[0017] a protruding portion protruding from the upper surface of the main body, provided with the exposure hole,

[0018] the main body has one or more recesses provided on the upper surface along the protruding portion and recessed in a thickness direction of the substrate when viewed from above in the thickness direction,

[0019] one or more of the recesses are provided on at least a portion of a circumferential direction of the protruding portion when viewed from above.

[0020] Effects of the Invention

[0021] According to the present disclosure, it is possible to provide a pressure sensor that suppresses mounting failure to a housing while maintaining waterproofness. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a plan view of the pressure sensor of the first embodiment of the present disclosure.

[0023] Figure 2 is a cross-sectional view of the pressure sensor of Figure 1 along line II-II.

[0024] Figure 3 is a cross-sectional view of the pressure sensor of Figure 1 along line III-III.

[0025] Figure 4 is an enlarged cross-sectional view of an EA1 region of the pressure sensor of Figure 3

[0026] is a cross-sectional view of an electronic device representing the first embodiment of the present disclosure, and is a view corresponding to line II-II in Figure 5 Figure 1

[0027] Figure 6 is a cross-sectional view of an electronic device representing the first embodiment of the present disclosure, and is a view corresponding to line III-III in Figure 1

[0028] Figure 7 is a plan view of a modified example of the pressure sensor of Figure 1

[0029] is a cross-sectional view of an electronic device provided with the pressure sensor of Figure 8 Figure 7 Figure 7 corresponding to line VIII-VIII in ​​​​​

[0030] Figure 9 is a plan view of the pressure sensor of the second embodiment of the present disclosure.

[0031] Figure 10 is an X-X line sectional view of the pressure sensor of Figure 9 DETAILED DESCRIPTION

[0032] (Insight that is the basis of the present disclosure)

[0033] The conventional pressure sensor (for example, the pressure sensor described in Patent Document 1) is mounted, for example, to a case that is provided with a case recess that houses a ring holding portion. At the time of mounting the pressure sensor, an O-ring is provided around the ring holding portion. In a state in which the pressure sensor is mounted to the case, the O-ring is positioned in an arrangement space of the O-ring that is surrounded by an upper surface of a main body portion, an outer peripheral surface of the ring holding portion, and an inner surface of the case recess. In the arrangement space, the O-ring is in contact with a surface of a resin package and the inner surface of the case recess. By these contacts, entry of liquid into the inside of the resin package is suppressed.

[0034] However, in the structure of the conventional pressure sensor, due to manufacturing tolerances of the resin package, the case, and the O-ring, the volume of the above-described arrangement space and the volume of the O-ring can change. Therefore, the filling rate of the O-ring in the arrangement space can become excessively large.

[0035] In a case in which the filling rate of the O-ring is excessively large, the O-ring is strongly flattened in the lateral direction between the outer peripheral surface of the ring holding portion and the inner wall surface of the case recess, and can be greatly deformed in the extending direction (longitudinal direction) of the ring holding portion. In this case, insertion of the ring holding portion into the case recess is hindered by the O-ring, and mounting failure of the pressure sensor can occur.

[0036] As a countermeasure against the filling rate of the O-ring becoming excessively large, it is considered to design the arrangement space of the O-ring to be larger, or to reduce the O-ring. However, in these countermeasures, the O-ring can not easily come into contact with the resin package and the case recess, and waterproofness can decrease.

[0037] Therefore, the inventors and others have conducted intensive research in order to suppress mounting failure of the pressure sensor to the case while maintaining waterproofness, and as a result, have found a structure of a pressure sensor that is provided with an avoidance space for avoiding a portion of the O-ring from the arrangement space. At the time of mounting the pressure sensor, the O-ring enters the avoidance space according to the magnitude of the pressing from the resin package and the case. Therefore, it is possible to suppress the filling rate of the O-ring from becoming excessively large while maintaining waterproofness. Based on this new insight, the inventors and others have completed the following disclosure.

[0038] Hereinafter, with reference to the drawings, the embodiments of the present disclosure will be described. Figure 1 ​Embodiments of the present disclosure will be described. Furthermore, in the following description, terms indicating specific directions or positions (for example, terms including "upper," "lower," "right," and "left") are used as necessary, but the use of these terms is for the sake of ease of understanding the present disclosure with reference to the drawings and does not limit the technical scope of the present disclosure by the meanings of these terms. In addition, the following description is merely illustrative in nature and is not intended to limit the present disclosure, its application, or its uses.

[0039] In the present specification, "electrically connected" includes any one of a case where electric current can flow between a plurality of constituent elements, a case where a plurality of constituent elements are capacitively coupled, and a case where a plurality of constituent elements are electromagnetically coupled.

[0040] <First Embodiment>

[0041] Reference Figures 1-3 A pressure sensor of the first embodiment of the present disclosure will be described. Figure 1 is a plan view of the pressure sensor of the first embodiment of the present disclosure. Figure 2 is Figure 1 a II-II cross-sectional view of the pressure sensor of Figure 3 is Figure 1 a III-III cross-sectional view of the pressure sensor of Figure 2 and the O-ring 6 described later in Figures 3-6 , Figure 8 and Figure 10 In the drawings, an X-Y-Z orthogonal coordinate system is shown for ease of explanation, but this coordinate system is for ease of understanding the present disclosure and does not limit the invention.

[0042] As shown in Figures 1-3 , the pressure sensor 1 includes a substrate 2, a detection element 3 provided on the substrate 2, and a cover member 4 provided on the substrate 2 in a manner of covering the detection element 3. As the pressure measured by the pressure sensor 1, there are absolute pressure, gauge pressure, differential pressure, pressure of gas flow, and the like.

[0043] As shown in Figure 2 , the substrate 2 has a lower surface 2a and an upper surface 2b on the opposite side thereof. For example, the substrate 2 is a wiring substrate such as a ceramic substrate, a resin substrate, or a lead frame. Here, the Z-axis direction is an example of the "thickness direction of the substrate" in the present disclosure. As shown in Figure 1 , in the present embodiment, the substrate 2 is a square shape having sides extending in the X-axis direction or the Y-axis direction in a plan view viewed from the Z direction.

[0044] A detection element 3 and a circuit element 21 are arranged on the substrate 2. The detection element 3 is a pressure sensor element that detects pressure. For example, the detection element 3 is a piezo-resistance type or electrostatic capacitance type pressure sensor element, and is a MEMS (Micro Electro Mechanical Systems) element. For example, the circuit element 21 is an element including an application-specific integrated circuit (ASIC). In this embodiment, the circuit element 21 includes a converter that converts a voltage signal output from the detection element 3 into a digital signal, a filter that filters the digital signal from the converter, a temperature sensor that detects temperature, a processor that corrects the filtered digital signal based on the temperature detected by the temperature sensor, and a memory that stores correction coefficients used when correcting the digital signal using the detected temperature.

[0045] like Figure 2 As shown, in this embodiment, the detection element 3 and the circuit element 21 are arranged side by side on the upper surface 2b of the substrate 2. For example, the detection element 3 and the circuit element 21 are each bonded to the substrate 2 via an adhesive member such as a die attach film or a die bond material. The detection element 3 and the circuit element 21 are electrically connected. In this embodiment, the detection element 3 and the circuit element 21 are electrically connected via a wire bond (not shown) connecting them.

[0046] Alternatively, the detection element 3 and the circuit element 21 may be electrically connected via the circuit of the substrate 2. For example, the detection element 3 and the circuit element 21 may each be connected to the circuit of the substrate 2 via wire bonds or bumps. Alternatively, the detection element 3 and the circuit element 21 may be arranged so as to overlap in the Z direction on the upper surface 2 b of the substrate 2.

[0047] The cover member 4 is provided on the upper surface 2b of the substrate 2, covering a portion of the detection element 3, the circuit element 21, and the wire bonding portion. The cover member 4 comprises: a main body 41 having an upper surface 41b facing the lower surface 41a of the substrate 2 and the opposite side thereof; and a protrusion 42 extending from the upper surface 41b of the main body 41 in the positive direction of the Z axis. Figure 2 and the following Figures 3-6 、 Figure 8 as well as Figure 10 In FIG. 4 , the boundary between the main body 41 and the protrusion 42 is indicated by a dotted line.

[0048] For example, the main body 41 and the protrusion 42 are respectively circular, elliptical, polygonal, etc. when viewed from above. Figure 1As shown, the main body 41 is rectangular with four corners 411 in plan view. Specifically, the main body 41 is provided on the entire surface of the upper surface 2b of the substrate 2 and is square in plan view. The protruding portion 42 is circular in plan view. As shown, the protruding portion 42 is formed in a tapered shape that becomes thinner as it advances in the positive direction of the Z axis, and has a top portion 422. The protruding portion 42 has an outer wall surface 42a that connects the top portion 422 and the upper surface 41b of the main body 41. That is, in the present embodiment, the protruding portion 42 is formed in a truncated cone shape. Figure 2 As shown, the protruding portion 42 is formed in a tapered shape that becomes thinner as it advances in the positive direction of the Z axis, and has a top portion 422. The protruding portion 42 has an outer wall surface 42a that connects the top portion 422 and the upper surface 41b of the main body 41. That is, in the present embodiment, the protruding portion 42 is formed in a truncated cone shape.

[0049] The protruding portion 42 is provided with an exposure hole 421 that exposes at least a portion of the detection element 3 to the outside. In the present embodiment, the exposure hole 421 extends in the Z direction and is open at the top portion 422. Thus, the cover member 4 covers the detection element 3 with the portion other than the exposure hole 421. In the present embodiment, the cover member 4 seals and protects a portion of the detection element 3, the circuit element 21, and the wire bonding portion.

[0050] For example, the cover member 4 is formed by transfer molding using two molds. On one mold, a collective substrate in which a plurality of substrates 2 are arranged in the planar direction is prepared. The other mold has a shape corresponding to the outer shape of the cover member 4, and is configured to be arranged between the collective substrate and the one mold. The cover member 4 is formed on the plurality of substrates 2 by filling resin between the collective substrate and the other mold. Alternatively, a FAM (Film Assisted Molding) process in which a release film is provided on the other mold can be performed.

[0051] As shown, the main body 41 has one or more recesses 5 provided on the upper surface 41b along the protruding portion 42 in plan view. As shown, Figure 1 As shown, the main body 41 has one or more recesses 5 provided on the upper surface 41b along the protruding portion 42 in plan view. As shown, Figure 3 As shown, each recess 5 is recessed in the Z direction. As shown, Figure 1 As shown, the recess 5 is provided on at least a portion of the circumferential direction of the protruding portion 42 in plan view.

[0052] In the first embodiment, the main body 41 has four recesses 5 provided only on a part of the circumferential direction of the protruding portion 42 in plan view. That is, the upper surface 41b of the main body 41 has a non-recessed region 412 adjacent to the protruding portion 42 on which the recess 5 is not provided. That is, the recess 5 is not provided on the entire circumference of the protruding portion 42.

[0053] Specifically, the four recesses 5 are formed in portions of the main body 41 from which a region of an imaginary square on the upper surface 41b excluding the protrusions 42 is removed when viewed from above. Here, the imaginary square has two sides extending in the X-axis direction and two sides extending in the Y-axis direction. In addition, the center of the imaginary square coincides with the imaginary central axis CA of the substrate 2 and the main body 41 when viewed from above. The length Ls1 of one side of the imaginary square is smaller than the diameter D42 of the protrusion 42. In addition, the length Ls2 of a diagonal of the imaginary square is larger than the diameter D42 of the protrusion 42.

[0054] In the present embodiment, the four recesses 5 are formed congruently when viewed from above. In addition, one of the four recesses 5 is provided between each of the corner portions 411 of the main body 41 and the protrusion 42 when viewed from above. Here, "between the corner portion 411 and the protrusion 42" means, for example, a region including a line connecting the corner portion 411 and the imaginary central axis CA of the protrusion 42 when viewed from above. In the present embodiment, the four recesses 5 are provided at equal intervals in the circumferential direction of the protrusion 42 when viewed from above. On the other hand, a non-recessed region 412 is provided between two adjacent ones of the four recesses 5 in the circumferential direction of the protrusion 42.

[0055] Figure 4 is Figure 3 an enlarged cross-sectional view of the EA1 region of the pressure sensor. As Figure 4 indicated, the recess 5 has a bottom surface 5a. The bottom surface 5a of the recess 5 is connected to the upper surface 41b of the main body 41 or the outer wall surface 42a of the protrusion 42 by an inner wall surface 5b. In the present specification, the upper surface 41b of the main body 41 is described as a structure in which an imaginary opening surface of the recess 5 is included, excluding the bottom surface 5a and the inner wall surface 5b of the recess 5.

[0056] The outer edge 424 of the lower end 423 of the protrusion 42 constitutes the edge 52 of the opening 51 of the recess 5. Therefore, the outer wall surface 42a of the protrusion 42 and the inner wall surface 5b of the recess 5 are formed as continuous surfaces in the Z direction. In the present embodiment, the outer wall surface 42a of the protrusion 42 and the inner wall surface 5b of the recess 5 are formed as coplanar surfaces.

[0057] As Figure 3 indicated, the main body 41 has a thickness TH1 between the lower surface 41a of the main body 41 and the bottom surface 5a of the recess 5 in the portion in which the recess 5 is formed. In addition, the main body 41 has a thickness TH2 between the lower surface 41a and the upper surface 41b of the main body 41 between the outer edge portion 413 of the main body 41 and the recess 5 in a direction intersecting (for example, orthogonal to) the Z direction. Here, the thickness TH2 is greater than the thickness TH1.

[0058] By providing the thicker portion between the outer edge portion 413 of the main body 41 and the recessed portion 5 than the thickness TH1, compared with a structure without the thicker portion, it is easy to supply resin to the entire collection substrate in the face direction of the collection substrate in the transfer molding.

[0059] As Figure 3 indicated, the pressure sensor 1 can further be provided with an O-ring 6 that surrounds the protruding portion 42 in plan view and is in contact with the outer wall surface 42a of the protruding portion 42. For example, the O-ring 6 is composed of an elastic member and has a circular or substantially circular cross section. In the present embodiment, the O-ring 6 has an inner diameter that is smaller than the diameter of the outer edge 424 of the protruding portion 42 (refer to FIG. 6). Thus, the O-ring 6 is disposed in the vicinity of the lower end 423 of the protruding portion 42 in an elastically deformed state and is in contact with the outer wall surface 42a of the protruding portion 42 over the entire circumference. Figure 1

[0060] As Figure 4 indicated, in at least a portion of the recessed portion 5, the length L5 of the recessed portion 5 in a direction parallel to the width of the O-ring 6 is smaller than the width W6 of the O-ring 6. For example, the width W6 of the O-ring 6 is measured in a state in which the pressure sensor 1 is not mounted to the housing 7 described later. In the present embodiment, the O-ring 6 is in contact with the outer wall surface 42a of the protruding portion 42 over the entire circumference, and thus is circular in plan view. Thus, the length L5 of the recessed portion 5 is measured in the radial direction of the imaginary central axis CA.

[0061] Referring to Figure 5 and Figure 6 , the mounting of the pressure sensor 1 to the housing 7 will be described. Figure 5 is a cross-sectional view of an electronic device of the first embodiment of the present disclosure, and is a view corresponding to the II-II line in Figure 1 . Figure 6 is a cross-sectional view of an electronic device of the first embodiment of the present disclosure, and is a view corresponding to the III-III line in Figure 1 .

[0062] The housing 7 is, for example, a housing of an electronic device on which the pressure sensor 1 is mounted. As Figure 6 indicated, the housing 7 is provided with a housing recessed portion 71 that accommodates the protruding portion 42 when the pressure sensor 1 is mounted to the housing 7. In Figure 6 the example shown, the housing recessed portion 71 is recessed from the top surface 7a of the housing 7. The housing recessed portion 71 has an inner surface 71a including a bottom surface 71b and an inner wall surface 71c. The inner wall surface 71c connects the bottom surface 71b of the housing recessed portion 71 and the top surface 7a of the housing 7 in the Z direction.

[0063] ​The housing recess 71 is configured so that, when the protrusion 42 is inserted, a space is formed that is surrounded by the outer wall surface 42a of the protrusion 42, the bottom surface 71b of the housing recess 71, and the inner wall surface 71c of the housing recess 71. This space is a space for arranging an O-ring when the pressure sensor 1 is mounted on the housing 7 (hereinafter also referred to as an arrangement space).

[0064] When the pressure sensor 1 is mounted on the housing 7, the pressure sensor 1 approaches the housing 7 in the Z direction, with the protrusion 42 inserted into the housing recess 71. During this approach, the O-ring 6 contacts the inner wall surface 71c of the housing recess 71 before the bottom surface 71b of the housing recess 71. As a result, the O-ring 6 is pressed in the width direction of the O-ring 6 by the protrusion 42 and the housing 7, causing it to elastically deform. During this elastic deformation, the width dimension of the O-ring 6 decreases, while the height dimension of the O-ring 6 (i.e., the Z direction) increases.

[0065] When the pressure sensor 1 is brought closer to the housing 7, the O-ring 6 contacts the bottom surface 71b of the housing recess 71. At this time, if the filling rate of the O-ring 6 in the arrangement space is too high, a portion of the O-ring 6 is pressed by the protrusion 42 and the housing 7 and enters the recess 5 (see FIG. Figure 6 That is, when the pressure sensor 1 is mounted on the housing 7, the recess 5 functions as an escape space for the O-ring 6 when the filling rate of the O-ring 6 is too high. Figure 6 ), it is possible to prevent the filling rate of the O-ring 6 from becoming too large.

[0066] As a portion of the O-ring 6 enters the recess 5, the non-recessed region 412 (see FIG. Figure 1 ) is stretched toward the adjacent recessed portion 5. Therefore, the portion of the O-ring 6 disposed on the non-recessed region 412 is stretched in the circumferential direction of the O-ring 6 and elastically deformed. By this elastic deformation, on the non-recessed region 412, as Figure 5 As shown, the cross-sectional area of ​​the O-ring 6 is reduced. Figure 5 ), it is also possible to prevent the filling rate of the O-ring 6 from becoming too large.

[0067] By placing the pressure sensor 1 at a predetermined position relative to the housing 7, the pressure sensor 1 is mounted. This completes the electronic device 100 comprising the pressure sensor 1 and the housing 7. In the electronic device 100, a portion of the O-ring 6 is positioned within the recess 5. This prevents the O-ring 6 from shifting in a plane direction intersecting the Z direction and escaping from the mounting space. In this embodiment, in the electronic device 100, the top surface 7a of the housing 7 contacts the upper surface 41b of the main body 41 of the pressure sensor 1.

[0068] <Modification example>

[0069] Using Figure 7 and Figure 8 , a modification example of the pressure sensor of the first embodiment will be described. Figure 7 is a plan view of a modification example of the pressure sensor of Figure 1 . Figure 8 is a cross-sectional view of an electronic device provided with the pressure sensor of Figure 7 , and is a view corresponding to VIII-VIII line in Figure 7 . In Figure 7 , the outer edge 424 of the lower end 423 of the protruding portion 42 in the pressure sensor 1 of the first embodiment is indicated by a single-dot chain line. In Figure 8 , the protruding portion 42 and the recessed portion 5 in the pressure sensor 1 of the first embodiment are indicated by a single-dot chain line. In the following description of the modification example, the same structures as those of the above first embodiment are omitted.

[0070] In the pressure sensor 1A of the modification example shown in Figure 7 , the protruding portion 42A is circular in plan view, and expands toward each corner portion 411 in the direction of extension of the diagonal line connecting between the corner portions 411. The protruding portion 42A has an outer edge 424A of the lower end 423. The protruding portion 42A has a distance L1 between the outer edge 424A adjacent to the recessed portion 5A and the imaginary central axis CA. In addition, the protruding portion 42A has a distance L2 between the outer edge 424A of the lower end 423 adjacent to the non-recessed portion region 412 and the imaginary central axis CA. The distance L1 is larger than the distance L2.

[0071] As shown in Figure 8 , the pressure sensor 1A constitutes the electronic device 100A by being mounted to the housing 7. By expanding the protruding portion 42A, each recessed portion 5A is smaller in plan view than each recessed portion 5 in the first embodiment. In addition, in the electronic device 100A, the arrangement space of the O-ring 6 is smaller than that of the electronic device 100 of the first embodiment.

[0072] By making the arrangement space of the O-ring 6 smaller, in the electronic device 100A, the O-ring 6 can be brought into contact with the bottom surface 71b of the housing recessed portion 71 more reliably. Therefore, it is possible to suppress the reduction in waterproofness of the electronic device 100.

[0073] According to the pressure sensor 1 of the first embodiment, when the filling rate of the O-ring 6 in the arrangement space of the O-ring 6 is large in the mounting of the pressure sensor 1 with respect to the case 7, the O-ring 6 pressed by the cover member 4 and the case 7 can enter the recess 5. Therefore, it is possible to suppress the O-ring 6 compressed by the outer wall surface 42a of the protrusion 42 and the inner wall surface 71c of the case recess 71 from largely passing over the top 422 of the protrusion 42. Thus, the mounting of the pressure sensor 1 is less likely to be hindered by the O-ring 6, and thus the pressure sensor 1 is easily arranged at the correct position with respect to the case 7. That is, it is possible to suppress the mounting failure of the pressure sensor 1 with respect to the case 7.

[0074] Further, according to the pressure sensor 1 of the first embodiment, the outer edge 424 of the lower end 423 of the protrusion 42 constitutes the edge 52 of the opening 51 of the recess 5. Therefore, the outer wall surface 42a of the protrusion 42 and the inner wall surface 5b of the recess 5 form a surface continuous in the Z direction. Thus, compared with a structure in which the outer edge 424 of the lower end 423 of the protrusion 42 does not constitute the edge 52 of the opening 51 of the recess 5, the O-ring 6 can easily enter the recess 5 when pressed by the outer wall surface 42a of the protrusion 42 and the inner surface 71a of the case recess 71. Therefore, the mounting of the pressure sensor 1 is less likely to be hindered by the O-ring 6, and thus it is possible to further suppress the mounting failure of the pressure sensor 1 with respect to the case 7.

[0075] Further, according to the pressure sensor 1 of the first embodiment, one or more recesses 5 are provided in a part of the circumferential direction of the protrusion 42 in plan view. In other words, the remaining part in the circumferential direction is not provided with the recess 5. In the non-recess region 412, the arrangement space is smaller than the part provided with the recess 5, and thus the upper portion of the O-ring 6 easily comes into contact with the bottom surface 71b of the case recess 71. Thus, even in the case where the filling rate of the O-ring is low, compared with a structure in which the recess 5 is provided in the entire range of the circumferential direction of the protrusion 42, it is possible to easily maintain the waterproof property of the pressure sensor 1.

[0076] Further, in the state where the pressure sensor 1 is mounted to the case 7, a part of the O-ring 6 is located in the recess 5 each having two end portions (i.e., not a ring shape). At this time, the part of the O-ring 6 located in the recess 5 is less likely to rise to the outside of the recess 5 at the end portions. Further, conversely, the part of the O-ring 6 located on the non-recess region 412 is also less likely to enter the recess 5 at the end portions. Thus, compared with a structure in which the recess 5 is provided in the entire range of the circumferential direction of the protrusion 42, it is possible to suppress the movement of the O-ring 6 in the circumferential direction, i.e., the rotation of the O-ring 6, in the state where the pressure sensor 1 is mounted to the case 7.

[0077] In the pressure sensor 1 provided with the plurality of recesses 5, as a portion of the O-ring 6 is pressed by the cover member 4 and the housing 7 into the recess 5, the portion of the O-ring 6 located on the non-recess region 412 is stretched toward the recess 5. At this time, if the elongation of the O-ring 6 is not balanced in the circumferential direction, the O-ring 6 is more likely to break at a portion where the elongation is larger than at a portion where the elongation is smaller. In addition, at the portion where the elongation is larger, the width of the O-ring 6 is smaller, and thus the O-ring 6 is less likely to contact the outer wall surface 42a of the protruding portion 42 or the inner wall surface 71c of the housing recess 71. Thus, the waterproofness of the pressure sensor 1 can be reduced.

[0078] According to the pressure sensor 1 of the first embodiment, the plurality of recesses 5 are provided at equal intervals in the circumferential direction of the protruding portion 42 in plan view, and thus the deviation of the elongation of the O-ring 6 can be suppressed. Thus, the O-ring 6 is less likely to break than in a structure in which the plurality of recesses 5 are not provided at equal intervals. In addition, the width of the O-ring 6 is less likely to be small, and thus the O-ring 6 is more likely to contact the outer wall surface 42a of the protruding portion 42 or the inner wall surface 71c of the housing recess 71. Thus, the waterproofness of the pressure sensor 1 can be more reliably maintained.

[0079] In addition, in the pressure sensor 1 of the first embodiment, the cover member 4 includes the main body 41 that is rectangular in plan view and the protruding portion 42 that is circular in plan view. In plan view, the distance between the central portion of each side of the main body 41 and the protruding portion 42 is smaller than the distance between each corner portion 411 of the main body 41 and the protruding portion 42. Thus, if the recess 5 is provided in the region between the central portion of each side of the main body 41 and the protruding portion 42, the main body 41 is likely to be large in the surface direction of the upper surface 41b. On the other hand, in a structure in which the recess 5 is provided in the region between each corner portion 411 and the protruding portion 42, the necessity of making the main body 41 large in order to provide the recess 5 is low. Thus, the large size of the recess 5 in the surface direction described above can be suppressed.

[0080] In addition, according to the pressure sensor 1 of the first embodiment, in at least a portion of the recess 5, the length of the recess 5 in a direction parallel to the width of the O-ring 6 is smaller than the width of the O-ring 6. Thus, a portion of the O-ring 6 is not located in the recess 5 in a state in which the pressure sensor 1 is not mounted to the housing 7. On the other hand, in a state in which the pressure sensor 1 is mounted to the housing 7, the O-ring 6 is deformed by being pressed by the outer wall surface 42a of the protruding portion 42 and the inner surface 71a of the housing recess 71. At this time, the O-ring 6 enters the recess 5 only in a case in which the filling rate of the O-ring 6 in the arrangement space of the O-ring 6 is high.

[0081] Thus, in a case where the filling rate of the O-ring 6 is low, the O-ring 6 does not enter the recess, and thus it is possible to reduce the possibility that the O-ring 6 comes off from the outer wall surface 42a of the protrusion 42 and the inner surface 71a of the housing recess 71. On the other hand, in a case where the filling rate of the O-ring 6 is high, a part of the O-ring 6 enters the recess 5, and thus it is possible to suppress the O-ring 6 from obstructing the mounting of the pressure sensor 1 to the housing 7. Thus, it is possible to provide the pressure sensor 1 that suppresses both the reduction in waterproofness and the obstruction of the mounting of the pressure sensor 1 to the housing 7.

[0082] Further, according to the electronic device 100 of the first embodiment, a part of the O-ring 6 is positioned in the recess 5, and thus it is possible to realize the electronic device 100 that suppresses the obstruction of the mounting of the pressure sensor 1 to the housing 7.

[0083] <Second Embodiment>

[0084] Reference Figure 9 and Figure 10 , a pressure sensor of a second embodiment of the present disclosure will be described. Figure 9 is a plan view of a pressure sensor of the second embodiment of the present disclosure. Figure 10 is Figure 9 a cross-sectional view of the pressure sensor of

[0085] In the pressure sensor 1B of the second embodiment and the pressure sensor 1 of the first embodiment, the shape and the size of the recess 5B are different. Further, in the following description of the second embodiment, the description of the same structure as the first embodiment is omitted.

[0086] As shown in Figure 9 , in the pressure sensor 1B, the main body 41 has one recess 5B provided to the upper surface 41b. The recess 5B is provided in the range of the entire circumference of the protrusion 42 when viewed from above. For example, the outer shape of the recess 5B is a circle, a polygon, or the like. In the present embodiment, the outer shape of the recess 5B is a square similar to the outer shape of the substrate 2 and the main body 41. Further, the center of the recess 5B coincides with the imaginary central axis CA of the substrate 2, the main body 41, and the protrusion 42 when viewed from above.

[0087] The recess 5B has a length L5B of the recess 5B in a direction parallel to the width of the O-ring 6 (refer to Figure 10 ). As shown in Figure 10 , in the present embodiment, the O-ring 6 is disposed around the protrusion 42 similarly to the O-ring 6 in the first embodiment. Thus, the length L5B of the recess 5B is a length in the radial direction of the imaginary central axis CA.

[0088] As shown in Figure 9As shown, the length L5B of the recess 5B is the shortest in the XZ cross section and the YZ cross section including the imaginary central axis CA when viewed from above. Figure 10 As shown, in at least a portion of the recess 5B, the length L5B of the recess 5B is smaller than the width W6 of the O-ring 6 .

[0089] In the pressure sensor 1B of the second embodiment, the recess 5B is provided along the entire circumference of the protrusion 42 in a plan view. Therefore, when pressed by the cover member 4 and the housing 7, the O-ring 6 is evenly positioned within the recess 5B along its entire circumference. This makes it easier for the upper portion of the O-ring 6 to contact the bottom surface 71b of the housing recess 71 along its entire circumference, compared to a configuration in which the recess 5B is provided only on a portion of the circumference of the protrusion 42. Consequently, a reduction in the waterproofness of the pressure sensor 1B can be minimized.

[0090] The present disclosure is not limited to the above-described embodiment and can be implemented in various other forms. For example, the above description describes an example in which the pressure sensors 1 , 1A, and 1B are provided with the O-ring 6 . However, the pressure sensors 1 , 1A, and 1B may not be provided with the O-ring 6 .

[0091] In the first embodiment, the four recesses 5 are formed to have congruent shapes when viewed from above, but the present disclosure is not limited to this. For example, the shape of each recess 5 when viewed from above may be circular, elliptical, polygonal, etc. When the main body 41 has multiple recesses 5, the shapes of the recesses 5 when viewed from above may all be the same or different.

[0092] Furthermore, in the above embodiment, the outer wall surface 42a of the protrusion 42 and the inner wall surface 5b of the recess 5 are formed coplanar, but the present disclosure is not limited to this. For example, when the outer wall surface 42a and the inner wall surface 5b are formed as a continuous surface along the Z direction, the outer wall surface 42a and the inner wall surface 5b may have different inclination angles with respect to the XY plane. Furthermore, the outer wall surface 42a and the inner wall surface 5b may be discontinuous. For example, the outer wall surface 42a and the inner wall surface 5b may be connected via the upper surface 41b of the main body 41.

[0093] In the above embodiment, while a portion of the O-ring 6 enters the recess 5 when the O-ring 6 contacts the bottom surface 71b of the housing recess 71, the present disclosure is not limited thereto. For example, a portion of the O-ring 6 may enter the recess 5 when the O-ring 6 contacts the outer wall surface 42a of the protrusion 42 and the inner wall surface 71c of the housing recess 71, but does not contact the bottom surface 71b of the housing recess 71.

[0094] By appropriately combining any of the various embodiments or modifications described above, the effects of each can be achieved. In addition, it is possible to combine the embodiments with each other, combine the embodiments with each other, or combine the embodiments with the embodiments, and it is also possible to combine the features of different embodiments or embodiments with each other.

[0095] While the present disclosure has been fully described in connection with the preferred embodiments with reference to the accompanying drawings, various modifications and alterations will be apparent to those skilled in the art, and it should be understood that such modifications and alterations are encompassed within the scope of the present disclosure as defined in the appended claims.

[0096] Various embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings. Finally, various aspects of the present disclosure will be described.

[0097] According to a first aspect of the present disclosure, there is provided a pressure sensor.

[0098] The pressure sensor includes:

[0099] substrate;

[0100] a detection element, disposed on the substrate and configured to detect pressure; and

[0101] a covering member provided on the substrate, having an exposure hole for exposing at least a portion of the detection element to the outside, and covering the detection element with a portion other than the exposure hole;

[0102] The covering member comprises:

[0103] a main body having an upper surface on a side opposite to a side facing the substrate; and

[0104] a protrusion protruding from an upper surface of the main body and provided with the exposing hole,

[0105] The main body has one or more recessed portions provided on the upper surface along the protruding portion when viewed from above in the thickness direction of the substrate and recessed in the thickness direction.

[0106] The one or more recessed portions are provided in at least a portion in the circumferential direction of the protruding portion in a plan view.

[0107] According to a second aspect of the present disclosure, there is provided the pressure sensor according to the first aspect, wherein an outer edge of a lower end of the protrusion constitutes an edge of an opening of the recess.

[0108] According to a third aspect of the present disclosure, there is provided the pressure sensor according to the first or second aspect, wherein:

[0109] the main body has one or more of the recesses disposed in a circumferential direction of the protruding portion when viewed from above,

[0110] an upper surface of the main body has a non-recessed region adjacent to the protruding portion and not provided with the recesses.

[0111] According to a fourth aspect of the present disclosure, there is provided the pressure sensor according to the third aspect, wherein the main body has a plurality of the recesses disposed at equal intervals in a circumferential direction of the protruding portion when viewed from above.

[0112] According to a fifth aspect of the present disclosure, there is provided the pressure sensor according to the fourth aspect, wherein

[0113] the main body is rectangular with four corners when viewed from above,

[0114] the protruding portion is circular when viewed from above,

[0115] one or more of the recesses are respectively disposed between one of the four corners and the protruding portion when viewed from above.

[0116] According to a sixth aspect of the present disclosure, there is provided the pressure sensor according to the fifth aspect, wherein the main body has four of the recesses.

[0117] According to a seventh aspect of the present disclosure, there is provided the pressure sensor according to the first or second aspect, wherein the main body has one of the recesses disposed in a range of an entire circumference of the protruding portion when viewed from above.

[0118] According to an eighth aspect of the present disclosure, there is provided the pressure sensor according to any one of the first to seventh aspects, wherein

[0119] the pressure sensor further includes an O-ring that surrounds the protruding portion when viewed from above and is in contact with an outer wall surface of the protruding portion,

[0120] in at least a part of the recesses, a length of the recesses in a direction parallel to a width of the O-ring is smaller than the width of the O-ring.

[0121] According to a ninth aspect of the present disclosure, there is provided an electronic device, wherein

[0122] the electronic device includes:

[0123] the pressure sensor according to the eighth aspect; and

[0124] a housing provided with a housing recess that accommodates the protruding portion,

[0125] the O-ring is in contact with an inner surface of the housing recess and an outer wall surface of the protruding portion,

[0126] A portion of the O-ring is located in the recess.

[0127] Industrial applicability

[0128] The pressure sensor and the electronic device according to the present disclosure are useful as various pressure sensors while suppressing mounting failure to the housing while maintaining waterproofness.

[0129] Explanation of reference signs

[0130] 1, 1A, 1B, pressure sensor; 2, substrate; 3, detection element; 4, cover member; 41, main body; 41b, upper surface; 411, corner portion; 412, non-recessed region; 42a, outer wall surface; 421, exposure hole; 423, lower end; 424, 424A, outer edge; 5, 5A, 5B, recess; 51, opening; 52, edge; 6, O-ring; 7, housing; 71, housing recess; 71a, inner surface; 100, 100A, electronic device.

Claims

1. A pressure sensor, wherein the pressure sensor includes: a substrate; a detection element provided on the substrate for detecting pressure; and a cover member provided on the substrate, having an exposure hole that exposes at least a part of the detection element to the outside, covering the detection element with a part other than the exposure hole, the cover member includes: a main body having an upper surface on a side opposite to a side on which a surface facing the substrate is located; and a protruding portion protruding from the upper surface of the main body, provided with the exposure hole, the main body has one or more recesses that are recessed along a thickness direction of the substrate when viewed from above along the protruding portion, one or more of the recesses are provided in at least a part of a circumferential direction of the protruding portion when viewed from above.

2. The pressure sensor according to claim 1, wherein an outer edge of a lower end of the protruding portion constitutes an edge of an opening of the recess.

3. The pressure sensor according to claim 1 or 2, wherein the main body has one or more of the recesses that are provided in a part of the circumferential direction of the protruding portion when viewed from above, the upper surface of the main body has a non-recessed region that is adjacent to the protruding portion and in which the recess is not provided.

4. The pressure sensor according to claim 3, wherein the main body has a plurality of the recesses that are provided at equal intervals in the circumferential direction of the protruding portion when viewed from above.

5. The pressure sensor according to claim 4, wherein the main body is rectangular having four corners when viewed from above, the protruding portion is circular when viewed from above, one or more of the recesses are respectively provided between one of the four corners and the protruding portion when viewed from above.

6. The pressure sensor according to claim 5, wherein the main body has four of the recesses.

7. The pressure sensor according to claim 1 or 2, wherein the main body has one of the recesses that is provided in a range of an entire circumference of the protruding portion when viewed from above.

8. The pressure sensor according to any one of claims 1 to 7, wherein the pressure sensor further includes an O-ring that surrounds the protruding portion when viewed from above and is in contact with an outer wall surface of the protruding portion, a length of the recess in a direction parallel to a width of the O-ring is smaller than the width of the O-ring in at least a part of the recess.

9. An electronic device, wherein the electronic device includes: the pressure sensor according to claim 8; and a housing provided with a housing recess that accommodates the protruding portion, the O-ring is in contact with an inner surface of the housing recess and the outer wall surface of the protruding portion, a part of the O-ring is located in the recess.

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