Pressure sensor and method of manufacturing the same

Abstract

A pressure sensor is provided that prevents foreign matter from adhering to the gel material, thereby suppressing changes in the characteristics of the pressure sensor. The pressure sensor of the present invention includes: a housing (2, 3) having an opening (31); a pressure-sensitive element (4) disposed within the housing; a gel material (5) having waterproof properties and sealing the pressure-sensitive element within the housing; and a plurality of coating members (6) laid on the surface of the gel material, the plurality of coating members being non-adhesive and configured not to be bonded to each other.

Description

Technical Field

[0001] This invention relates to a waterproof pressure sensor with a sealed pressure-sensitive element and a method for manufacturing the same. Background Technology

[0002] Such pressure sensors are known in the past, for example, as described in Patent Document 1 (Japanese Patent Application Publication No. 2017-181302).

[0003] Patent Document 1 describes a pressure sensor comprising: a housing having an opening; a pressure sensing element disposed within the housing opposite the opening; and a gel material that seals the pressure sensing element within the housing. Pressure is applied to the pressure sensing element by means of the gel material. The gel material has high adhesiveness to adhere tightly to the housing and the pressure sensing element, thereby preventing moisture from entering the pressure sensing element.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-181302 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] However, in the pressure sensor of Patent Document 1, foreign matter easily adheres to its surface due to the high adhesiveness of the gel material. This foreign matter adhering to the gel material causes changes in the characteristics of the pressure sensor. Furthermore, removing the foreign matter adhering to the gel material is also difficult.

[0009] Therefore, the purpose of this invention is to provide a pressure sensor that prevents foreign matter from adhering to the gel material, thereby suppressing changes in the characteristics of the pressure sensor.

[0010] Solution for solving the problem

[0011] To achieve the aforementioned objectives, the pressure sensor of the present invention includes:

[0012] The shell has an opening;

[0013] A pressure-sensitive element is disposed within the housing;

[0014] A gel material, which is waterproof, seals the pressure-sensitive element within the housing; and

[0015] Multiple coated components are laid on the surface of the gel material.

[0016] The plurality of covered components are non-adhesive and are configured not to be bonded together.

[0017] The effects of the invention

[0018] According to the present invention, foreign matter does not easily adhere to the gel material, thereby suppressing changes in the characteristics of the pressure sensor. Attached Figure Description

[0019] Figure 1 This is a side view of the pressure sensor according to the first embodiment of the present invention.

[0020] Figure 2 yes Figure 1 A top view of the pressure sensor.

[0021] Figure 3 yes Figure 2 Sectional view along line A1-A1.

[0022] Figure 4 This is a schematic diagram showing the configuration of multiple covered components for a pressure sensor according to the second embodiment of the present invention.

[0023] Figure 5A It is shown Figure 1 A cross-sectional view of an example of a method for manufacturing a pressure sensor.

[0024] Figure 5B It is shown Figure 1 A cross-sectional view of an example of a method for manufacturing a pressure sensor.

[0025] Figure 5C It is shown Figure 1 A cross-sectional view of an example of a method for manufacturing a pressure sensor.

[0026] Figure 6 This is a flowchart of a method for manufacturing a pressure sensor according to the first embodiment of the present invention.

[0027] Figure 7 This is a flowchart of a first method for manufacturing a pressure sensor according to the second embodiment of the present invention.

[0028] Figure 8 This is a flowchart of a second method for manufacturing a pressure sensor according to the second embodiment of the present invention.

[0029] Figure 9 This is a schematic diagram showing the configuration of multiple covered components related to the pressure sensor of the present invention. Detailed Implementation

[0030] One aspect of the present invention provides a pressure sensor comprising: a housing having an opening; a pressure-sensitive element disposed within the housing; a gel material having waterproof properties and sealing the pressure-sensitive element within the housing; and a plurality of coated members laid on the surface of the gel material, the plurality of coated members being non-adhesive and not bonded together.

[0031] According to this structure, since the surface of the gel material is covered by multiple coated components, foreign matter is prevented from adhering to the gel material. Furthermore, since the multiple coated components are non-adhesive, foreign matter adhering to the coated components can be easily removed. Therefore, changes in the characteristics of the pressure sensor can be suppressed.

[0032] Furthermore, since the multiple coated components are not bonded together, a coated structure consisting of multiple coated components attached to the surface of the gel material at multiple locations is not formed. Therefore, no stress is generated relative to the deformation of the gel material, thus suppressing changes in the pressure sensor characteristics caused by such stress variations. In addition, foreign objects cannot reach the surface of the gel material through the gaps created in the coated structure, further suppressing changes in the pressure sensor characteristics.

[0033] Preferably, the plurality of coated components are particles having a spherical or substantially spherical shape.

[0034] According to this structure, compared to cases where the coated components have other shapes, the contact area between each coated component and the surface of the gel material is smaller. Therefore, the adhesion of each coated component to the surface of the gel material is less affected by deformation of the gel material. That is, during the use of the pressure sensor, the coated components are less likely to peel off from the surface of the gel material. Consequently, the effect of preventing foreign matter from adhering to the gel material can be performed more reliably, thereby further suppressing changes in the characteristics of the pressure sensor.

[0035] Preferably, the plurality of coated components are two or more types of particles with different sphere radii.

[0036] According to this structure, the multiple coated components contain at least larger particles and smaller particles. In this case, when multiple coated components are laid on the surface of the gel material, the smaller particles can be arranged to fill the gaps between the larger particles. Therefore, compared to the case where the multiple coated components consist only of larger particles, a larger area of ​​the gel material surface is covered by the multiple coated components. Consequently, it is possible to further prevent foreign matter from adhering to the gel material, thereby more reliably suppressing changes in the characteristics of the pressure sensor.

[0037] Preferably, when the spherical radius of the nth largest particle of the plurality of coated components is set to Ra and the spherical radius of the (n+1)th largest particle of the plurality of coated components is set to Rb, the following formula is satisfied.

[0038]

Formula 1

[0039]

[0040] According to this structure, when multiple coated components are laid on the surface of the gel material, the (n+1)th largest particle can be more reliably positioned in the gaps between the nth largest particles. Thus, a larger area of ​​the gel material surface is covered by multiple coated components. Consequently, foreign matter adhesion to the gel material can be further prevented, thereby more reliably suppressing changes in the pressure sensor's characteristics.

[0041] Preferably, the plurality of coated components are composed of at least one of silicone particles, silica particles, and acrylic particles.

[0042] Based on this structure, it is possible to achieve multiple non-adhesive, non-bonded coated components.

[0043] A method for manufacturing a pressure sensor according to one aspect of the present invention includes the following steps: a preparation step in which an assembly is prepared, the assembly including a housing having an opening, a pressure-sensitive element disposed within the housing, and a waterproof gel material that seals the pressure-sensitive element within the housing; and a laying step in which a plurality of coated components are laid on the surface of the gel material.

[0044] According to this method, since the surface of the gel material is covered by multiple coated components, foreign matter is prevented from adhering to the gel material. Therefore, changes in the characteristics of the pressure sensor can be suppressed.

[0045] Alternatively, the manufacturing method may further include a discharge step in which the coated component that is not attached to the surface of the gel material is discharged from the opening.

[0046] According to this method, since the coated component not attached to the surface of the gel material is discharged, it prevents the coated component from moving above the gel material or flowing out from the opening during the use of the pressure sensor. Therefore, during the use of the pressure sensor, the magnitude and distribution of the pressure exerted on the gel material by the coated component remain constant, thus suppressing changes in the characteristics of the pressure sensor.

[0047] Alternatively, in the manufacturing method, the plurality of coated components may be two or more particles having a spherical or substantially spherical shape and having different sphere radii.

[0048] According to this method, each coated component is easier to roll compared to those with other shapes. Therefore, each coated component is less likely to remain on top of other coated components when laid on the surface of the gel material, and can reach the surface of the gel material more easily. Taking advantage of this, when laying multiple coated components on the surface of the gel material, it is not necessary to position each coated component in a predetermined location, thus simplifying the laying process.

[0049] Furthermore, because multiple coated components roll on the surface of the gel material to fill the gaps between them, the gaps between the coated components are filled more reliably. As a result, a larger area of ​​the gel material surface is covered by multiple coated components. Consequently, foreign matter adhesion to the gel material can be further prevented, thereby more reliably suppressing changes in the pressure sensor's characteristics.

[0050] Furthermore, according to this method, the multiple coated components comprise at least a few larger particles and a few smaller particles. In this case, when the multiple coated components are laid on the surface of the gel material, the smaller particles can be arranged to fill the gaps between the larger particles. Thus, compared to the case where the multiple coated components consist only of larger particles, a larger area of ​​the gel material surface is covered by the multiple coated components. Consequently, it is possible to further prevent foreign matter from adhering to the gel material, thereby more reliably suppressing changes in the characteristics of the pressure sensor.

[0051] Alternatively, the manufacturing method may further include an additional laying step after the laying step, in which a plurality of small covering components smaller than the covering component are laid on the surface of the gel material.

[0052] According to this method, compared to the case where multiple small coated components are laid simultaneously, multiple small coated components can be more reliably positioned within the gaps between the coated components. As a result, a larger area of ​​the gel material's surface is covered by multiple coated components and multiple small coated components. Consequently, it is possible to further prevent foreign matter from adhering to the gel material, thereby more reliably suppressing changes in the pressure sensor's characteristics.

[0053] Alternatively, the manufacturing method may further include an additional discharge step after the additional laying step, in which the small coated components that are not attached to the surface of the gel material are discharged from the opening.

[0054] Furthermore, according to this manufacturing method, since the small coated components not attached to the surface of the gel material are discharged, it prevents these small coated components from moving above the gel material or flowing out from the opening. Therefore, during the use of the pressure sensor, the magnitude and distribution of the pressure exerted on the gel material by the small coated components remain constant, thus suppressing changes in the characteristics of the pressure sensor.

[0055] Embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention is not limited to these embodiments.

[0056] Furthermore, in the accompanying drawings, substantially identical components are labeled with the same reference numerals, thus omitting descriptions.

[0057] In the following text, for ease of explanation, terms such as "upper surface," "lower surface," and "side" are used to indicate direction, but these terms do not imply limitation on the usage state of the pressure sensor of the present invention.

[0058] [First Embodiment]

[0059] Reference Figures 1-3 The pressure sensor of the first embodiment of the present invention is described. Figure 1 This is a side view of the pressure sensor according to the first embodiment of the present invention. Figure 2 yes Figure 1 A top view of the pressure sensor. Figure 3 yes Figure 2 Sectional view along line A1-A1.

[0060] like Figure 1 As shown, the pressure sensor 1 of the first embodiment includes a substrate 2 and a cylindrical member 3 disposed on one side of the substrate 2. The substrate 2 and the cylindrical member 3 constitute an example of the "casing" of the present invention. Figure 3 As shown, a pressure-sensitive element 4 is provided on the substrate 2 inside the cylindrical member 3. The pressure-sensitive element 4 is sealed by a gel material 5 provided inside the cylindrical member 3. A plurality of coated members 6 are provided on the surface 5a of the gel material 5.

[0061] The substrate 2 can be, for example, a PCB substrate, a lead frame, etc. In this embodiment, the substrate 2 is a ceramic substrate.

[0062] The cylindrical member 3 is joined at one end to one side of the substrate 2 to prevent leakage of the uncured gel material 5. This joining can be achieved, for example, using an epoxy adhesive. In this embodiment, the cylindrical member 3 is joined to the electrode (not shown) of the substrate 2 using a conductive paste (not shown).

[0063] An opening 31 is formed at the end of the cylindrical member 3 on the side opposite to the substrate 2.

[0064] The cylindrical component 3 can be a cylindrical shape with a cross-section such as a circular shape, a rectangular shape, or a polygonal shape.

[0065] In this embodiment, the cylindrical member 3 has a large-diameter portion 32 in the shape of a cylinder and a small-diameter portion 33 in the shape of a cylinder with a diameter smaller than that of the large-diameter portion 32. The large-diameter portion 32 is joined to the substrate 2 at one end. The small-diameter portion 33 is joined to the end of the large-diameter portion 32 on the side opposite to the substrate 2 at one end. In addition, an opening 31 is formed at the other end of the small-diameter portion 33.

[0066] The small diameter portion 33 is provided for mounting an O-ring (not shown) when the pressure sensor 1 is installed on other components. The O-ring is fitted to the outside of the small diameter portion 33. However, the small diameter portion 33 is not necessarily required when an O-ring is not used.

[0067] Cylindrical component 3 is made of metals such as stainless steel, ceramics such as alumina, etc.

[0068] In this embodiment, the cylindrical member 3 is made of stainless steel. Therefore, the cylindrical member 3 is electrically connected to the substrate 2 via a conductive paste and the electrodes. However, the substrate 2 and the cylindrical member 3 do not necessarily need to be electrically connected.

[0069] like Figure 3 As shown, an integrated circuit chip 8 is bonded to the substrate 2 on the inner side of the cylindrical member 3 using chip mounting material 71. The integrated circuit chip 8 controls the pressure-sensitive element 4.

[0070] In this embodiment, the integrated circuit chip 8 is an ASIC (Application Specific Integrated Circuit) chip.

[0071] The pressure-sensitive element 4 is disposed overlapping the integrated circuit chip 8 using chip mounting material 72. The pressure-sensitive element 4 has a diaphragm that detects pressure changes by flexural deformation.

[0072] The chip mounting materials 71 and 72 can be, for example, paste-like chip mounting materials or chip mounting films. In this embodiment, the chip mounting materials 71 and 72 are chip mounting films.

[0073] The pressure-sensitive element 4, the integrated circuit chip 8, and the substrate 2 are electrically connected to each other. These electrical connections can be achieved, for example, using bumps, substrate wiring, etc. In this embodiment, the substrate 2 and the integrated circuit chip 8 are connected by a bonding wire 91. Furthermore, the integrated circuit chip 8 and the pressure-sensitive element 4 are connected by a bonding wire 92.

[0074] The pressure-sensitive element 4 and the integrated circuit chip 8 are sealed by a gel material 5 disposed inside the cylindrical member 3. The gel material 5 is obtained by allowing uncured gel material to flow from the opening 31 into the inside of the cylindrical member 3 and cure. The gel material 5 transmits the pressure applied to its surface 5a to the diaphragm of the pressure-sensitive element 4.

[0075] Furthermore, the gel material 5 has adhesive properties and adheres tightly to the substrate 2, the cylindrical component 3, the pressure-sensitive element 4, the integrated circuit chip 8, the chip mounting materials 71 and 72, and the bonding wires 91 and 92. This prevents moisture from entering the substrate 2, the pressure-sensitive element 4, the integrated circuit chip 8, and the bonding wires 91 and 92. In other words, it imparts waterproofness to the pressure sensor 1.

[0076] The gel material 5 can be, for example, a fluorinated gel or a fluorosilicone gel. In this embodiment, the gel material 5 is silicone.

[0077] Multiple coated components 6 are laid on the surface 5a of the gel material 5. In this specification, "laid" means that the multiple coated components 6 are laid in such a way that they cover most of the surface 5a of the gel material 5.

[0078] Multiple coated components 6 are attached to the surface 5a of the gel material 5 using the adhesive properties of the gel material 5. The multiple coated components 6 prevent foreign matter from adhering to the gel material 5 by covering the surface 5a of the gel material 5.

[0079] The multiple coated components 6 are non-adhesive, meaning they are not bonded to each other. In this specification, "non-adhesive" means that foreign matter attached to the coated component can be easily separated from the coated component. Furthermore, "bonded" means a bond that is not easily separated even when a force is applied to pull the coated components 6 apart, such as a bond involving atoms, a bond using adhesiveness, or a bond formed by pulling each other closer using magnetic or electrostatic forces.

[0080] By making the multiple coated components 6 non-adhesive, foreign matter attached to the coated components 6 can be easily removed using, for example, running water.

[0081] When multiple coated members 6 are joined together, each coated member 6 is attached to the surface 5a of the gel material 5 and is joined together. That is, a coated structure is formed by multiple coated members 6, each of which is attached to the surface 5a of the gel material 5. When the gel material 5 deforms due to changes in temperature, pressure, etc., the coated structure generates stress that is intended to eliminate the deformation.

[0082] If the bond between the multiple coated components 6 cannot detach with the deformation of the gel material 5, the magnitude of the aforementioned stress will change. This change in stress will cause a change in the characteristics of the pressure sensor.

[0083] Furthermore, gaps are created at the points where the bonds between the multiple coated components 6 detach, allowing the material to reach the surface 5a of the gel material 5. If foreign matter enters these gaps and adheres to the gel material 5, it will cause changes in the characteristics of the pressure sensor.

[0084] On the other hand, since the plurality of coated members 6 of the present invention are configured not to be joined together, the coated structure is not formed. Therefore, the characteristic changes of the pressure sensor that occur as described above can be suppressed.

[0085] The multiple coated components 6 can be, for example, silica particles, acrylic particles, etc. In this embodiment, the multiple coated components 6 are silicone particles with a spherical or approximately spherical shape having an average particle size of 100.00 ± 1.00 μm. Furthermore, the "average particle size" is the converted particle size of standard particles measured using the Coulter counting method.

[0086] According to the pressure sensor 1 of this embodiment, since the surface 5a of the gel material 5 is covered by a plurality of coated members 6, foreign matter is prevented from adhering to the gel material 5. Furthermore, since the plurality of coated members 6 are non-adhesive, foreign matter adhering to the coated members 6 can be easily removed. Therefore, changes in the characteristics of the pressure sensor 1 can be suppressed.

[0087] Furthermore, since the multiple coated members 6 are not bonded to each other, a coated structure consisting of multiple coated members 6 attached to the surface 5a of the gel material 5 in each coated member 6 is not formed. Therefore, no stress is generated relative to the deformation of the gel material 5, thus suppressing changes in the characteristics of the pressure sensor 1 caused by such stress changes. In addition, foreign objects cannot reach the surface 5a of the gel material 5 through the gaps created in the coated structure, further suppressing changes in the characteristics of the pressure sensor 1.

[0088] Furthermore, according to this embodiment, since each coated member 6 is a particle with a spherical or approximately spherical shape, the contact area between each coated member 6 and the surface 5a of the gel material 5 is smaller compared to cases where each coated member 6 has other shapes. Therefore, the adhesion of each coated member 6 to the surface 5a of the gel material 5 is less affected by deformation of the gel material 5. That is, during the use of the pressure sensor 1, the coated member 6 is less likely to peel off from the surface 5a of the gel material 5. Consequently, the effect of preventing foreign matter from adhering to the gel material 5 can be performed more reliably, thereby further suppressing changes in the characteristics of the pressure sensor 1.

[0089] Furthermore, according to the pressure sensor 1 of this embodiment, since the plurality of coated components 6 are composed of at least one of silicone particles, silicon oxide particles and acrylic particles, it is possible to achieve a plurality of non-adhesive, non-bonded coated components 6.

[0090] [Manufacturing method of pressure sensor according to the first embodiment]

[0091] Next, refer to Figures 5A-5C and Figure 6 An example of a method for manufacturing the pressure sensor 1 according to the first embodiment of the present invention will be described. Figures 5A-5C It is shown Figure 1 A cross-sectional view of an example of a method for manufacturing a pressure sensor. Figure 6 This is a flowchart of a method for manufacturing a pressure sensor according to the first embodiment of the present invention.

[0092] (Preparation process S1)

[0093] First, such as Figure 5A As shown, an assembly 10 for manufacturing a pressure sensor 1 is prepared. The assembly 10 includes a substrate 2 and a cylindrical member 3 joined to one end of a face of the substrate 2. Inside the cylindrical member 3, an integrated circuit chip 8 is bonded to the substrate 2 using a chip mounting material 71. A pressure-sensitive element 4 is bonded to the integrated circuit chip 8 using a chip mounting material 72. The substrate 2 and the integrated circuit chip 8 are connected by bonding wires 91. Furthermore, the integrated circuit chip 8 and the pressure-sensitive element 4 are connected by bonding wires 92. The pressure-sensitive element 4 and the integrated circuit chip 8 are sealed by a gel material 5 disposed inside the cylindrical member 3.

[0094] (Laying process S2)

[0095] Then, as Figure 5B As shown, a plurality of coating members 6 are laid on the surface 5a of the gel material 5 via the opening 31. The laying process S2 can be performed, for example, by blowing the plurality of coating members 6 onto the surface 5a of the gel material 5 using a sprayer, dispenser, or the like.

[0096] Multiple coated members 6 that reach the surface 5a of the gel material 5 are attached to the surface 5a of the gel material 5 by utilizing the adhesive properties of the gel material 5. On the other hand, coated members 6 that are not attached to the surface 5a of the gel material 5 and overlap with other coated members 6 can move according to external forces.

[0097] (Discharge process S3)

[0098] Next, the coated component 6, which is not attached to the surface 5a of the gel material 5, is discharged through the opening 31. For example, as... Figure 5C As shown, the orientation of the assembly 10 is changed so that the opening 31 is below the direction of gravity. As a result, the coating member 6 that is not attached to the surface 5a of the gel material 5 falls down due to gravity and is discharged from the opening 31.

[0099] Furthermore, it is possible to apply vibration to the assembly 10 while keeping the opening 31 facing downwards in the direction of gravity. This allows the coated component 6, which is not attached to the surface 5a of the gel material 5, to fall more reliably.

[0100] According to this manufacturing method, since the surface 5a of the gel material 5 is covered by a plurality of coated members 6, foreign matter is prevented from adhering to the gel material 5. Therefore, changes in the characteristics of the pressure sensor 1 can be suppressed.

[0101] Furthermore, according to this manufacturing method, since the coating member 6 that is not attached to the surface 5a of the gel material 5 is discharged, it prevents the coating member 6 from moving above the gel material 5 or flowing out from the opening 31 during the use of the pressure sensor 1. As a result, during the use of the pressure sensor 1, the magnitude and distribution of the pressure applied to the gel material 5 by the coating member 6 remain unchanged, thus suppressing changes in the characteristics of the pressure sensor 1.

[0102] Furthermore, according to this manufacturing method, each coated member 6 is easier to roll compared to those with other shapes. Therefore, each coated member 6 is less likely to remain on other coated members 6 when laid on the surface 5a of the gel material 5, and can reach the surface 5a of the gel material 5 more easily. Taking advantage of this, when laying multiple coated members 6 on the surface 5a of the gel material 5, it is not necessary to position each coated member 6 in a predetermined position, thus simplifying the laying process.

[0103] Furthermore, since the multiple coated members 6 can roll on the surface 5a of the gel material 5 to fill the gaps between them, the gaps between the coated members 6 are filled more reliably. Thus, a larger area of ​​the surface 5a of the gel material 5 is covered by the multiple coated members 6. Consequently, foreign matter can be further prevented from adhering to the gel material 5, thereby more reliably suppressing changes in the characteristics of the pressure sensor 1.

[0104] [Second Implementation]

[0105] Next, refer to Figure 4 The pressure sensor of the second embodiment of the present invention is described. Figure 4 This is a schematic diagram showing the configuration of multiple covered components for a pressure sensor according to the second embodiment of the present invention.

[0106] The pressure sensor of the second embodiment differs from the pressure sensor 1 of the first embodiment in that the plurality of coated members 6 are two or more particles having different spherical radii.

[0107] The following describes the configuration of multiple coated components 6 on the surface 5a of the gel material 5.

[0108] In the pressure sensor of the second embodiment, the plurality of coated members 6 are two types of particles with different spherical radii. That is, the plurality of coated members 6 have large-diameter particles 61 and small-diameter particles 62. The small-diameter particles 62 are an example of the "small coated members" of the present invention.

[0109] The radius of the sphere of the large-diameter particle 61 is greater than that of the small-diameter particle 62.

[0110] and, Figure 4 The spherical radius Ra of the large-diameter particle 61 and the spherical radius Rb of the small-diameter particle 62 shown satisfy the following formula.

[0111]

Formula 2

[0112]

[0113] In pressure sensors with such a structure, such as Figure 4 As shown, small-diameter particles 62 can be arranged on the surface 5a of gel material 5 in a way that fills the gaps between large-diameter particles 61.

[0114] In this embodiment, both the large-diameter particle 61 and the small-diameter particle 62 are silicone particles.

[0115] According to the pressure sensor of this embodiment, the small-diameter particles 62 can be configured to fill the gaps between the large-diameter particles 61 when multiple coated members 6 are laid on the surface 5a of the gel material 5. Therefore, compared to the case where the multiple coated members 6 are composed only of large-diameter particles 61, a larger area of ​​the surface 5a of the gel material 5 is covered by the multiple coated members 6. Consequently, it is possible to further prevent foreign matter from adhering to the gel material 5, thereby more reliably suppressing changes in the characteristics of the pressure sensor.

[0116] Furthermore, according to the pressure sensor of this embodiment, when multiple coated members 6 are laid on the surface 5a of the gel material 5, the (n+1)th largest particle (i.e., the small-diameter particle 62) can be more reliably disposed in the gaps between the nth largest particle (i.e., the large-diameter particle 61). Thus, a larger area of ​​the surface 5a of the gel material 5 is covered by the multiple coated members 6. Consequently, foreign matter adhering to the gel material 5 can be further prevented, thereby more reliably suppressing changes in the characteristics of the pressure sensor.

[0117] [First manufacturing method of the pressure sensor according to the second embodiment]

[0118] Next, refer to Figure 7 An example of a method for manufacturing a pressure sensor according to the second embodiment of the present invention will be described. Figure 7 This is a flowchart of a first method for manufacturing a pressure sensor according to the second embodiment of the present invention.

[0119] In this manufacturing method, compared with the aforementioned manufacturing method ( Figure 6Similarly, the preparation step S11, the laying step S12, and the discharge step S13 are performed. In the laying step S12, multiple large-diameter particles 61 and multiple small-diameter particles 62 are laid simultaneously. Therefore, in the discharge step S13, the large-diameter particles 61 and small-diameter particles 62 that are not attached to the surface 5a of the gel material 5 are discharged.

[0120] According to this manufacturing method, it is possible to obtain a pressure sensor in which small diameter particles 62 are arranged on the surface 5a of the gel material 5 in such a way as to fill the gaps between large diameter particles 61.

[0121] [Second Manufacturing Method of the Pressure Sensor of the Second Embodiment]

[0122] Next, refer to Figure 8 Another example of a method for manufacturing a pressure sensor according to the second embodiment of the present invention will be described. Figure 8 This is a flowchart of a second method for manufacturing a pressure sensor according to the second embodiment of the present invention.

[0123] In this manufacturing method, compared with the aforementioned manufacturing method ( Figure 6 Similarly, the preparation step S21, the laying step S22, and the discharge step S23 are performed. In the laying step S22, multiple large-diameter particles 61 are laid. Therefore, in the discharge step S23, the large-diameter particles 61 that are not attached to the surface 5a of the gel material 5 are discharged.

[0124] (Additional laying procedure S24)

[0125] Next, similar to the laying process S2, a plurality of small-diameter particles 62 are laid on the surface 5a of the gel material 5. Thus, some of the small-diameter particles 62 are arranged to fill the gaps between the large-diameter particles 61 and adhere to the surface 5a of the gel material 5. On the other hand, the small-diameter particles 62 that are not adhered to the surface 5a of the gel material 5 can move under external force.

[0126] (Additional discharge process S25)

[0127] Next, similar to the discharge process S3, small-diameter particles 62 that are not attached to the surface 5a of the gel material 5 are discharged.

[0128] According to this manufacturing method, compared to the case where small-diameter particles 62 and large-diameter particles 61 are laid simultaneously, multiple small-diameter particles 62 can be more reliably disposed in the gaps between the large-diameter particles 61. As a result, a larger area of ​​the surface 5a of the gel material 5 is covered by both large-diameter particles 61 and small-diameter particles 62. Consequently, foreign matter adhesion to the gel material 5 can be further prevented, thereby more reliably suppressing changes in the characteristics of the pressure sensor.

[0129] Furthermore, according to this manufacturing method, since the small-diameter particles 62 that are not attached to the surface 5a of the gel material 5 are discharged, it is prevented that the small-diameter particles 62 move above the gel material 5 or flow out from the opening 31. As a result, the magnitude and distribution of the pressure exerted on the gel material 5 by the small-diameter particles 62 remain unchanged during the use of the pressure sensor, thus suppressing changes in the characteristics of the pressure sensor.

[0130] Furthermore, the present invention is not limited to the aforementioned embodiments and can be implemented in various other ways. For example, although the pressure-sensitive element 4 and the integrated circuit chip 8 are arranged overlappingly in the aforementioned manner, the present invention is not limited to this. For example, the pressure-sensitive element 4 and the integrated circuit chip 8 may be respectively bonded to the substrate 2 and arranged laterally to each other.

[0131] Furthermore, although in the aforementioned manner multiple coated members 6 are attached to the surface 5a of the gel material 5, the present invention is not limited thereto. For example, it may also be as follows: Figure 5B As shown, there is a coated member 6 that overlaps with other coated members 6 and has a surface 5a that is not attached to the gel material 5.

[0132] Furthermore, although in the aforementioned manner the plurality of coated members 6 have a spherical or substantially spherical shape with an average particle size of 100.00 ± 1.00 μm, the present invention is not limited thereto. For example, each coated member 6 may be a member formed by combining multiple particles having a spherical or substantially spherical shape. Furthermore, the average particle size of the plurality of coated members 6 may be greater than or less than the aforementioned average particle size. Alternatively, the coated members 6 may have a shape other than a spherical or substantially spherical shape.

[0133] Furthermore, although in the aforementioned second embodiment the plurality of coated members 6 are two types of particles with different spherical radii, the present invention is not limited thereto. For example, the plurality of coated members 6 may also be three types of particles with different spherical radii. In this case, such as Figure 9 As shown, the plurality of coated components 6 have large-diameter particles 61, small-diameter particles 62, and microparticles 63. Microparticles 63 are disposed, for example, in the gaps between the plurality of large-diameter particles 61 and small-diameter particles 62, and can be attached to the surface 5a of the gel material 5.

[0134] Furthermore, although the large-diameter particles 61 and small-diameter particles 62 are silicone particles in the aforementioned second embodiment, the present invention is not limited thereto. For example, the large-diameter particles 61 and small-diameter particles 62 may also be made of different materials.

[0135] Furthermore, although the discharge steps S3, S13, S23 and the additional discharge step S25 are performed in the aforementioned manner, the present invention is not limited thereto. For example, if a coated member 6 not attached to the surface 5a of the gel material 5 is not produced in the laying steps S2, S12, S22 and the additional laying step S24, then the discharge steps S3, S13, S23 and the additional discharge step S25 are not required.

[0136] Industrial availability

[0137] The pressure sensor according to the present invention is useful for devices and apparatuses used in a wide variety of environments because foreign matter does not easily adhere to the gel material, thus suppressing changes in the characteristics of the pressure sensor.

[0138] Explanation of reference numerals in the attached figures

[0139] 1. Pressure sensor; 2. Substrate; 3. Cylindrical component; 4. Pressure-sensitive element; 5. Gel material; 5a. Surface; 6. Coated component; 8. Integrated circuit chip; 10. Assembly; 31. Opening; 32. Large diameter portion; 33. Small diameter portion; 61. Large diameter particle; 62. Small diameter particle; 63. Microparticle; 71, 72. Chip mounting material; 91, 92. Bonding wire.

Claims

1. A pressure sensor, wherein, The pressure sensor includes: The shell has an opening; A pressure-sensitive element is disposed within the housing; A gel material, which is waterproof, seals the pressure-sensitive element within the housing; and Multiple coated components are laid on the surface of the gel material. The multiple covered components are non-adhesive and do not bond together. The multiple coated components are two or more types of particles with different sphere radii. When the spherical radius of the nth largest particle of the plurality of coated components is set as Ra, and the spherical radius of the (n+1)th largest particle of the plurality of coated components is set as Rb, the following equation is satisfied: 。 2. The pressure sensor according to claim 1, wherein, The plurality of coated components are particles with a spherical shape.

3. The pressure sensor according to claim 1 or 2, wherein, The plurality of coated components are composed of at least one of silicone particles, silica particles, and acrylic particles.

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