WO2024048783A1 - Switch and method for manufacturing same - Google Patents

Abstract

Provided are: a pressure-sensitive switch with which a change in a characteristic resulting from the switch being used over time can be suppressed; and a method for manufacturing the same. The switch comprises: a base in which a recess is formed; a first electrode disposed on a bottom surface of the recess; a second electrode disposed on the periphery of the recess; a dielectric which is disposed inside the recess, and which is electrically connected to the first electrode; a conductive sheet which is disposed above the dielectric, and which is electrically connected to the second electrode; and an insulative space-retaining member which has a through hole formed at the center thereof, and which retains a space between the dielectric and the conductive sheet on the periphery of the through hole. The dielectric and the conductive sheet are arranged so that a contact surface area between the conductive sheet and the dielectric changes according to a pressing force which presses the conductive sheet in the direction of the dielectric. A depression following the outer edge of the through hole is formed on one surface of the space-retaining member, and the space-retaining member is arranged so that the depression is positioned on the conductive sheet side.

Description

Switch and its manufacturing method

The present disclosure relates to a switch and a method for manufacturing the same.

Capacitive pressure-sensitive switches are used as operation switches for electronic devices. A pressure-sensitive switch has a dielectric material and a conductive resin arranged with a gap in between, and when the conductive resin is pressed, a change in the size of the gap between the dielectric material and the conductive resin occurs. Detects changes in capacitance.

JP 2020-123481A describes a switch that forms a gap between a dielectric material and a conductive resin using a spacer having an opening in the center.

The characteristics of such a switch may change due to repeated pressing operations. Therefore, in such a switch, it is required to suppress changes in characteristics due to use.

The present disclosure has been made to solve the above-mentioned problems, and aims to provide a pressure-sensitive switch and a method for manufacturing the same that can suppress changes in characteristics due to use.

A switch according to an embodiment of the present disclosure includes a base in which a recess is formed, a first electrode placed on the bottom surface of the recess, a second electrode placed around the recess, and a second electrode placed inside the recess. A dielectric material is electrically connected to the first electrode, a conductive sheet is placed above the dielectric material and electrically connected to the second electrode, and a through hole is formed in the center, and the dielectric material and the conductive material are connected around the through hole. an insulating spacing member that maintains a distance between the dielectric sheet and the conductive sheet, and the conductive sheet and the dielectric sheet are separated according to the pressing force that presses the conductive sheet in the direction of the dielectric material. A recess is formed on one side of the spacing member along the outer edge of the through hole, and the spacing member is arranged such that the recess is located on the side of the conductive sheet. characterized by being done.

Furthermore, the dent is preferably a sag formed when the through hole is formed by punching.

The switch further includes a frame member that surrounds the conductive sheet and is adhered to the base from above the spacing member, and a protective sheet that is adhered to the frame member and protects the conductive sheet by covering the conductive sheet. It is preferable.

Furthermore, in the switch, the height from the bottom of the recess to the top of the dielectric is preferably equal to the height from the bottom of the recess to the top of the second electrode.

Further, in the switch, the height from the bottom of the recess to the top of the spacing member is preferably equal to the height from the bottom of the recess to the top of the second electrode.

A method for manufacturing a switch according to an embodiment of the present disclosure includes preparing a base having a recess formed therein, a first electrode disposed on the bottom surface of the recess, and a second electrode disposed around the recess; A dielectric to be electrically connected to the first electrode is placed in the recess, an insulating spacing member with a through hole formed in the center is placed above the dielectric, and a conductive sheet is placed above the spacing member. The dielectric and the conductive sheet are arranged so that the contact area between the conductive sheet and the dielectric changes in accordance with the pressing force that presses the conductive sheet in the direction of the dielectric, and a spacing member is used. A recess is formed on one surface of the through hole along the outer edge of the through hole, and the spacing member is arranged such that the recess is located on the side of the conductive sheet.

Further, in the switch manufacturing method, the step of placing the dielectric in the recess includes accommodating the dielectric in the recess so as to electrically connect to the first electrode via an uncured adhesive member. With the dielectric fixed so that the upper surface is at a predetermined height with respect to the upper surface of the base, the adhesive member is cured to have a desired thickness and the dielectric is electrically connected to the first electrode. Preferably, the method includes forming an electrically conductive adhesive layer.

In addition, in the switch manufacturing method, a protrusion extending toward the upper surface of the dielectric is formed on the other surface of the spacing member along the outer edge of the through hole, and the step of arranging the dielectric in the recess is , a dielectric is accommodated in the recess so as to be electrically connected to the first electrode via an uncured adhesive member, and the upper surface of the spacing member disposed on the other surface of the dielectric touches the upper surface of the base. With the dielectric fixed at a predetermined height as a reference, the adhesive member is cured to form a conductive adhesive layer having a desired thickness and electrically connecting the dielectric to the first electrode. Preferably, it includes:

The pressure-sensitive switch and the manufacturing method thereof according to the present disclosure make it possible to suppress changes in characteristics due to use.

FIG. 1 is a perspective view of a switch according to a first embodiment. FIG. 2 is an exploded perspective view of the switch shown in FIG. 1. FIG. 2 is a sectional view of the switch shown in FIG. 1. FIG. FIG. 2 is a schematic cross-sectional view of a spacing member for explaining the structure around the through hole shown in FIG. 1. FIG. FIG. 2 is a flow diagram showing the flow of a method for manufacturing the switch shown in FIG. 1. FIG. (A) is a diagram showing the step indicated by S1 in FIG. 5, (B) is a diagram showing the step indicated by S2 in FIG. 5, and (C) is a diagram showing the step indicated by S3 in FIG. 5. It is a diagram. (A) is a diagram showing the step shown by S4 in FIG. 5, (B) is a diagram showing the step shown by S5 in FIG. 5, and (C) is a diagram showing the step shown by S6 in FIG. 5. It is a diagram. FIG. 3 is a sectional view of a switch according to a second embodiment. 9 is a flowchart showing the flow of a method for manufacturing the switch 2 shown in FIG. 8. FIG. (A) is a diagram showing the step shown by S11 in FIG. 9, (B) is a diagram showing the step shown by S12 in FIG. 9, and (C) is a diagram showing the step shown by S13 in FIG. 9. It is a diagram. (A) is a diagram showing the step shown in S14 in FIG. 9, (B) is a diagram showing the step shown in S15 in FIG. 9, and (C) is a diagram showing the step shown in S16 in FIG. 9. It is a diagram. (A) is a diagram showing the step shown by S17 in FIG. 9, and (B) is a diagram showing the step shown by S18 in FIG. 9. FIG. 7 is a sectional view of a switch according to a third embodiment. 14 is a flow diagram showing the flow of a method for manufacturing the switch shown in FIG. 13. FIG. (A) is a diagram showing the step shown by S13 in FIG. 14, and (B) is a diagram showing the step shown by S15 in FIG. 9. 9 is a graph showing the relationship between the thickness of the adhesive layer and the depth of the recess shown in FIG. 8.

Hereinafter, various embodiments of the present disclosure will be described with reference to the drawings. It should be noted that the technical scope of the present disclosure is not limited to those embodiments, but extends to the claimed inventions and equivalents thereof.

(Switch according to the first embodiment)
FIG. 1 is a perspective view of the switch 1 according to the first embodiment, and FIG. 2 is an exploded perspective view of the switch 1. The switch 1 includes a base 11, wiring 12, a dielectric 13, a spacing member 14, a conductive sheet 15, a frame member 16, a protective sheet 17, and a holding member 18. The switch 1 is a capacitive pressure-sensitive switch that detects a pressing operation based on a change in the capacitance of a capacitor formed inside.

The base 11 is a substantially rectangular parallelepiped member made of insulating ceramic or resin. The ceramic is aluminum nitride, aluminum oxide (alumina), LTCC (Low Temperature Co-fired Ceramics), or the like. The resin is phenol resin, epoxy resin, polyimide resin, polyester resin, or the like. A recess 111 in which the dielectric 13 can be accommodated is formed on the upper surface of the base 11 . Rounded notches are formed at the four corners of the outer peripheral side surface of the base 11.

The wiring 12 has a first electrode 121, a second electrode 122, a first terminal 123, and a second terminal 124. The first electrode 121, the second electrode 122, the first terminal 123, and the second terminal 124 are all conductive thin films formed of a conductive material such as copper. The first electrode 121 is arranged on the bottom surface of the recess 111 of the base 11. The second electrode 122 is arranged around the recess 111 on the upper surface of the base 11 . The first terminal 123 is arranged to cover two adjacent notches among the four notches formed on the outer peripheral side of the base 11, and the second terminal 124 covers the other two adjacent notches. It is arranged like this. The first terminal 123 is electrically connected to the first electrode 121 via internal wiring of the base 11, which will be described later. The second terminal 124 is electrically connected to the second electrode 122 on the upper surface of the base 11 . The first electrode 121 and the first terminal 123 and the second electrode 122 and the second terminal 124 are electrically insulated from each other. A resist 125 made of an insulating resin such as phenol resin or polyimide resin is arranged on the outer edge of the upper surface of the second electrode 122 and the upper surface of the base 11 .

The dielectric 13 is formed into a substantially rectangular parallelepiped using a ferroelectric material such as barium titanate having a dielectric constant of 1.0 or more. The dielectric 13 is placed inside the recess 111 so that its bottom surface is in contact with the first electrode 121 . The bottom surface of the dielectric 13 is adhered to the first electrode 121 using a conductive material such as silver paste. Thereby, the dielectric 13 is electrically connected to the first electrode 121.

The spacing member 14 is a rectangular flat plate-shaped insulating member made of synthetic resin such as polyimide resin. The spacing member 14 functions as a spacer that maintains the spacing between the dielectric 13 and the conductive sheet 15. A through hole 141 is formed in the center of the spacing member 14, passing through from the top surface to the bottom surface. The through hole 141 is formed by punching the spacer 14 .

The conductive sheet 15 is formed into a flat plate shape from a conductive rubber made of flexible synthetic resin such as silicone mixed with metal powder or conductive carbon black. The conductive sheet 15 is placed above the dielectric 13 with the spacing member 14 in between. The center of the bottom surface of the conductive sheet 15 faces the center of the top surface of the dielectric 13 via the through hole 141 of the spacing member 14 . The distance between the bottom surface of the conductive sheet 15 and the top surface of the dielectric 13 is a distance corresponding to the thickness of the spacing member 14. Note that the conductive sheet 15 may be another elastic body having conductivity, such as a film made of polyimide with aluminum vapor-deposited or a conductive resin sheet.

The frame member 16 is made of synthetic resin such as polyimide or polyphthalamide. The frame member 16 surrounds the conductive sheet 15 and is arranged on the upper surface of the base 11 so that the outer edge of the frame member 16 coincides with the outer edge of the base 11. The bottom surface of the frame member 16 is adhered to the top surface of the base 11 with a synthetic adhesive such as an acrylic resin adhesive. The frame member 16 holds the conductive sheet 15 due to the viscosity of the synthetic resin forming the frame member 16 .

The protective sheet 17 is formed into a thin film shape from a highly waterproof synthetic resin such as polyimide or polyamide. The protective sheet 17 is arranged to cover the conductive sheet 15. The protective sheet 17 protects the dielectric 13, the spacing member 14, and the conductive sheet 15 from water droplets, moisture, dust, and the like.

The protective sheet 17 has a base portion 171, an inclined portion 172, and a pressing surface 173. The base portion 171 is a planar portion surrounding the inclined portion 172 and the push-down surface 173. By bonding the base 171 to the upper surface of the frame member 16 with a synthetic adhesive, the protective sheet 17 is arranged to cover the conductive sheet 15. The outer edge of the base 171 matches the outer edges of the base 11 and the frame member 16. The inclined portion 172 has an annular planar shape surrounding the push-down surface 173, and is a surface that slopes upward toward the inside from the connection portion with the base portion 171. The push-down surface 173 is a circular plane that projects upward from the base 171.

When the press-down surface 173 is pressed down, the press-down surface 173 moves downward and comes into contact with the upper surface of the conductive sheet 15. When the pressing surface 173 is further pressed in this state, the pressing surface 173 presses the conductive sheet 15 in the direction of the dielectric 13 . The conductive sheet 15 pressed in the direction of the dielectric 13 curves downward, and the bottom surface of the conductive sheet 1 comes into contact with the top surface of the dielectric 13 .

When the pressing force is small, only the central portion of the pressed portion of the conductive sheet 15 comes into contact with the upper surface of the dielectric 13. As the pressing force increases, the conductive sheet 15 comes into contact with the upper surface of the dielectric 13 over a wider range centered on the pressed central portion. That is, the conductive sheet 15 and the dielectric 13 are arranged so that the contact area between the conductive sheet 15 and the dielectric 13 changes depending on the pressing force that presses the conductive sheet 15 in the direction of the dielectric 13 . By increasing the contact area between the conductive sheet 15 and the dielectric 13, the capacitance of the capacitor formed by the conductive sheet 15 and the first electrode 121 increases. The first terminal 123 and the second terminal 124 output an electrical signal indicating the capacitance of the capacitor. In this way, the pressing force applied to the pressing surface 173 is detected.

The holding member 18 is made of a synthetic resin with high rigidity such as polyamide resin. The holding member 18 is formed with a through hole 181 that penetrates from the upper surface to the lower surface. The holding member 18 is a member for holding a pressing member (not shown) for pressing the pressing surface 173 so as to be slidable in the direction of pressing the pressing surface 173 inside the through hole 181 . Further, the bottom surface of the holding member 18 is adhered to the protective sheet 17 with a synthetic adhesive.

FIG. 3 is a cross-sectional view of the switch 1 taken along III-III in FIG. 1. The wiring 12 further includes a bottom wiring 126 and an internal wiring 127. The bottom wiring 126 is arranged near the bottom of the base 11 and is electrically connected to the first terminal 123. The internal wiring 127 is arranged below the recess 111 inside the base 11 and connects the first electrode 121 and the bottom wiring 126. The first electrode 121 and the first terminal 123 are electrically connected by the bottom wiring 126 and the internal wiring 127.

FIG. 4 is a schematic cross-sectional view of the spacing member 14 for explaining the structure around the through hole 141. The through hole 141 is formed by shearing a part of the flat plate-shaped spacing member 14 by punching. When forming the through hole 141 by punching, a rounded sag 142 is formed along the outer edge of the through hole 141 on one surface (the upper surface in FIG. 4) of the spacing member 14, and on the other side. A burr 143 is formed on the surface along the outer edge of the through hole 141 and protrudes in the punching direction (downward in FIG. 4) of the punching process. The sag 142 and the burr 143 are formed when the material constituting the spacing member 14 is pulled in the pulling direction. The spacing member 14 is arranged such that the sag 142 is located on the conductive sheet 15 side and the burr 143 is located on the dielectric 13 side. The sag 142 is also called a dent, and the burr 143 is also called a protrusion.

When the conductive sheet 15 is pressed, a large force is applied to the contact point of the conductive sheet 15 with the outer edge of the through hole 141. At this time, if the burr 143 is located on the side of the conductive sheet 15, the burr 143 bites into the conductive sheet 15. As the burr 143 repeatedly bites into the conductive sheet 15 as the switch 1 is used, the conductive sheet 15 is deformed and the distance and contact area between the conductive sheet 15 and the dielectric change, resulting in a change in capacitance. There is a risk. By arranging the spacing member 14 of the switch 1 so that the burr 143 is located on the side of the dielectric 13, the burr 143 is prevented from digging into the conductive sheet 15.

Furthermore, even if the burr 143 is located on the side of the dielectric 13, if the sag 142 is not formed on the side of the conductive sheet 15 and the outer edge of the through hole 141 is angular, the outer edge of the through hole 141 is located on the side of the conductive sheet 13. It bites into. Therefore, as in the case where the burr 143 is located on the side of the conductive sheet 15, there is a possibility that the capacitance will change. By arranging the spacing member 14 of the switch 1 so that the rounded sag 142 is located on the side of the conductive sheet 15, the outer edge of the through hole 141 is prevented from digging into the conductive sheet 15. This prevents the characteristics of the switch 1 from changing.

FIG. 5 is a flowchart showing the flow of the method for manufacturing the switch 1, and FIGS. 6 and 7 are schematic cross-sectional views for explaining each step of the method for manufacturing the switch 1. Although FIGS. 6 and 7 show the manufacturing process of one switch 1, the process is not limited to this example, and multiple switches 1 can be manufactured at once by using a collective board in which multiple bases 11 are connected. may be done.

First, as shown in FIG. 6(A), the base 11 is prepared (step S1). A recess 111 is formed in the base 11 , and the base 11 has a first electrode 121 placed on the bottom surface of the recess 111 and a second electrode 122 placed around the recess 111 . The first electrode 121 is electrically connected to the first terminal 123, and the second electrode 122 is electrically connected to the second terminal 124.

Next, as shown in FIG. 6(B), the dielectric 13 electrically connected to the first electrode 121 is placed in the recess 111 (step S2). A thermosetting conductive adhesive layer is formed to cover the first electrode on the bottom surface of the recess 111. After the dielectric 13 is placed above the conductive adhesive layer, the base 11 is heated to harden the conductive adhesive layer. In this way, the dielectric 13 is placed within the recess 111 and electrically connected to the first electrode 121.

Next, as shown in FIG. 6C, an insulating spacing member 14 with a through hole formed in the center by punching is placed above the dielectric 13 (step S3). The spacing member 14 is arranged such that the sag 142 is located on the conductive sheet 15 side and the burr 143 is located on the dielectric 13 side.

Next, as shown in FIG. 7(A), the conductive sheet 15 is placed above the spacing member 14 (step S4). The conductive sheet 15 is placed above the spacing member 14 by bonding the bottom surface of the frame member 16 to the top surface of the base 11 while being held by and integrated with the frame member 16. . In this way, the conductive sheet 15 is arranged so that the distance between the dielectric 13 and the conductive sheet 15 is maintained around the through hole 141 of the spacing member 14 .

Next, as shown in FIG. 7(B), the protective sheet 17 is placed so as to cover the conductive sheet 15 (step S5). The protective sheet 17 is arranged by being adhered to the upper surface of the frame member 16.

Next, as shown in FIG. 7(C), the holding member 18 is placed above the protective sheet 17 (step S6). The holding member 18 is arranged with its lower surface adhered to the protective sheet 17. The switch 1 is manufactured in the manner described above.

As described above, the switch 1 includes the insulating spacing member 14 that maintains the spacing between the dielectric 13 and the conductive sheet 15 around the through hole 141. The spacing member 14 is arranged so that the sag 142 formed at the outer edge of the through hole 141 when the through hole 141 is formed by punching is located on the side of the conductive sheet 15. This makes it possible for the switch 1 to suppress changes in characteristics due to use.

Further, the switch 1 includes a protective sheet 17 that is adhered to the frame member 16 and protects the conductive sheet 15 by covering the conductive sheet 15. This improves the dustproof, waterproof, and moistureproof properties of the switch 1, and suppresses changes in the characteristics of the switch due to dust, water droplets, humidity, and the like.

The switch 1 also includes a first terminal 123 arranged on the outer periphery of the base 11 and electrically connected to the first electrode 121, and a first terminal 123 arranged on the outer periphery of the base 11 and electrically connected to the second electrode 122. It further has a second terminal 124. By arranging the first terminal 123 and the second terminal 124 on the outer periphery of the base 11, the internal structure of the base 11 is simplified and the switch 1 is miniaturized.

The following modifications may be applied to the switch 1.

In the above description, it is assumed that the sag 142 is rounded, but the present invention is not limited to this example. The sag 142 may have a so-called C-chamfer shape in which one surface of the spacing member 14 and the inner peripheral side surface of the through hole 141 are connected by an inclined plane. In this case as well, the outer edge of the through hole 141 is prevented from digging into the conductive sheet 15, and the characteristics of the switch 1 are prevented from changing.

In the above description, the through hole 141 is formed by punching, but the invention is not limited to this example. For example, the spacing member 14 having the through holes 141 may be formed by a molding process such as injection molding. In this case, the spacing member 14 may be molded using a mold in which the outer edge of the through hole 141 is rounded, and after the spacing member 14 is molded, the outer edge of the through hole 141 is rounded. Chamfering (R-chamfering or C-chamfering) may be performed to give a shape with a .

In the above description, the switch 1 is assumed to have the protective sheet 17, but the switch 1 does not need to have the protective sheet 17. That is, the user may press the conductive sheet 15 directly or indirectly via a pressing member.

In the above description, the first terminal 123 and the second terminal 124 are arranged on the outer periphery of the base 11, but the first terminal 123 and the second terminal 124 are arranged on the top surface, bottom surface, etc. of the base 11. It may be placed at a location.

(Switch according to second embodiment)
FIG. 8 is a cross-sectional view of the switch 2 according to the second embodiment in a cross section corresponding to the III-III cross section in FIG. The switch 2, like the switch 1, is a capacitive pressure-sensitive switch that detects a pressing operation based on a change in the capacitance of a capacitor formed inside.

Switch 2 differs from switch 1 in that it has an adhesive layer 19 with a desired height. Further, the switch 2 differs from the switch 1 in that the height of the top surface of the dielectric 13 substantially matches the height of the top surface of the second electrode 122 disposed on the top surface of the base 11 . The configurations and functions of the components of the switch 2 other than the height of the top surface of the adhesive layer 19 and the dielectric 13 are the same as those of the components of the switch 1 with the same reference numerals, so a detailed description will not be provided here. Omitted.

The adhesive layer 19 is formed of a conductive adhesive material, fixes the dielectric 13 to the first electrode 121, and electrically connects the first electrode 121 and the dielectric 13. The height of the adhesive layer 19 is adjusted so that the height of the upper surface of the dielectric 13 substantially matches the height of the upper surface of the second electrode 122 disposed on the upper surface of the base 11.

In the switch 2, the first height H1, which is the height from the top surface of the bottom plate 112 of the base 11 to the top surface of the dielectric 13, is the height from the top surface of the bottom plate 112 of the base 11 to the top surface of the second electrode 122. is equal to the second height H2. The first height H1 is calculated from the height H121 of the first electrode 121, the height H19 of the adhesive layer 19, and the height H13 of the dielectric 13. H1 = H121 + H19 + H13
It is indicated by. On the other hand, the second height H2 is calculated from the height H113 of the side wall 113 of the base 11 and the height H122 of the second electrode 122: H2 = H113 + H122
It is indicated by.

The dielectric 13 is arranged so that the upper surface of the dielectric 13 is at a predetermined height with respect to the upper surface of the base 11. For example, the dielectric 13 is arranged so that its upper surface is at the same height as the second electrode 122 arranged on the upper surface of the base 11. Since the second electrode 122 and the resist 125 are arranged on the upper surface of the base 11, the upper surface of the base 11 coincides with the upper surface of the second electrode 122 or the upper surface of the resist 125. In the example shown in FIG. 3, the dielectric 12 is arranged so that its upper surface is at the same height as the upper surface of the second electrode 122. In the example shown in FIG. The dielectric 13 may be arranged such that its upper surface is at the same height as the resist 125 arranged on the upper surface of the base 11.

FIG. 9 is a flowchart showing the flow of the method for manufacturing the switch 2, and FIGS. 10 to 12 are schematic cross-sectional views for explaining each step of the method for manufacturing the switch 2. 10(A) shows step S11 shown in FIG. 9, FIG. 10(B) shows step S12 shown in FIG. 9, and FIG. 10(C) shows step S13 shown in FIG. 9. 11(A) shows step S14 shown in FIG. 9, FIG. 11(B) shows step S15 shown in FIG. 9, and FIG. 11(C) shows step S16 shown in FIG. 9. 12(A) shows step S17 shown in FIG. 9, and FIG. 12(B) shows step S18 shown in FIG. 9. Although FIGS. 10 to 12 show a manufacturing process for manufacturing a plurality of switches 2 using the assembly method, the present invention is not limited to this example, and only one switch 2 may be manufactured.

First, as shown in FIG. 10(A), a collective board in which a plurality of bases 11 are connected is prepared (step S11). A recess 111 is formed in each base 11, and each base 11 has a first electrode 121 disposed on the bottom surface of the recess 111 and a second electrode 122 disposed around the recess 111. have The first electrode 121 is electrically connected to the first terminal 123, and the second electrode 122 is electrically connected to the second terminal 124. Further, a resist 116 is disposed on a portion of the upper surface of the second electrode 122 of the base 11 and between the second electrodes 122 of two adjacent bases 11.

Next, as shown in FIG. 10(B), an uncured adhesive member G is placed on the first electrode 121 (step S12). The adhesive member G has conductivity at least in a cured state. The adhesive member G is, for example, a silver paste containing epoxy resin.

Next, as shown in FIG. 10(C), the dielectric 13 is attracted to the attraction plate P1 (step S13). A plurality of protrusions P11 having an outer diameter larger than the outer diameter of the recesses 111 are formed on the suction plate P1 so as to face each recess 111 of the collective substrate. The dielectric 13 is placed on the protrusion P11. The suction plate P1 attracts the dielectric 12 placed on the protrusion P11 by lowering the air pressure inside the air intake port P12 formed in the protrusion P11. A receiving portion P13 having a lower height than the protruding portion P11 is arranged around the protruding portion P11.The receiving portion P13 is arranged so that the resist 125 faces the receiving portion P13. The difference between the height of the protruding portion P11 and the height of the receiving portion P13 is larger than the difference between the height of the resist 125 and the height of the second electrode 122.

Next, as shown in FIG. 11(A), the dielectric 13 is bonded to be electrically connected to the first electrode 121 (step S14). The collective substrate on which the adhesive member G is placed is turned upside down and placed on the suction plate P1 so that the dielectric 13 is accommodated in the recess 111. At this time, the bottom surface of the dielectric 13 comes into contact with the adhesive member G. Further, since the outer diameter of the protrusion P11 is larger than the outer diameter of the recess 111, the outer edge of the protrusion P11 comes into contact with the periphery of the recess 111. Therefore, the height of the upper surface of the dielectric 13 is the same as the height of the periphery of the recess 111. The weight plate Q1 is placed on the collective substrate so that the periphery of the recess 111 and the outer edge of the protrusion P11 more reliably abut.

By heating the collective substrate with the dielectric 13 adsorbed to the adsorption plate P1, the adhesive member G is cured to form a conductive adhesive layer 19, and the dielectric 13 is electrically connected to the first electrode 121. and is bonded to the first electrode 121. At this time, since the dielectric 13 is attracted to the attraction plate P1, the dielectric 13 is not lifted up due to curing and shrinkage of the adhesive member G. That is, by curing the adhesive member G, it is desired that the height of the upper surface of the dielectric 13 becomes the same height as the height of the second electrode 122 disposed around the recess 111, that is, on the upper surface of the base 11. An adhesive layer 19 is formed having a thickness of . Therefore, the upper surface of the dielectric 13 is positioned with high precision based on the height around the recess 111.

Next, as shown in FIG. 11B, an insulating spacing member 14 with a through hole 141 formed in the center is placed above the dielectric 13 bonded to the first electrode 121 (step S15).

Next, as shown in FIG. 11(C), the conductive sheet 15 is placed above the spacing member 14 (step S16). The conductive sheet 15 is held by the frame member 16 and integrated with the frame member 15, and the bottom surface of the frame member 16 is adhered to the top surface of the base 11, so that the conductive sheet 15 is disposed above the spacing member 14. . In this way, the conductive sheet 15 is arranged so that the distance between the dielectric material 13 and the conductive sheet 15 is maintained around the through hole 141 of the spacing member 14 .

Next, as shown in FIG. 12(A), the protective sheet 17 is placed so as to cover the conductive sheet 15 (step S17). The protective sheet 17 is arranged by being adhered to the upper surface of the frame member 16.

Next, as shown in FIG. 12(B), the holding member 18 is placed above the protective sheet 17 (step S18). The holding member 18 is arranged with its lower surface adhered to the protective sheet 17.

Finally, the collective substrate is cut into individual pieces (step S19). In the manner described above, a plurality of switches 2 are manufactured.

As explained above, the switch 2 is manufactured by curing the adhesive layer 19 while adsorbing the dielectric 13 and bonding the dielectric 13 while electrically connected to the first electrode 121. . As a result, the dielectric 13 is positioned with high accuracy based on the height of the top surface of the base 11. Generally, when manufacturing the base 11, it is difficult to make the depth of the recess 111 constant with high precision. Further, the thickness of the dielectric 13 also varies. Therefore, when the dielectric 13 is positioned based on the height of the bottom surface of the recess 111, the distance between the dielectric 13 and the conductive sheet 15 tends to vary. On the other hand, in the method for manufacturing the switch 2, the dielectric 13 is positioned based on the height of the top surface of the base 11 rather than the bottom surface of the recess 111, so that the distance between the dielectric 13 and the conductive sheet 15 is This reduces the variation in

Further, the dielectric 13 is arranged so that its upper surface is at the same height as the second electrode 122 arranged on the upper surface of the base 11, and the switch 2 is connected to the dielectric 13 and the conductive sheet above the dielectric 13. It has a spacing member 14 for maintaining a predetermined spacing between the two. As a result, the distance between the dielectric 13 and the conductive sheet 15 is defined by the spacing member 13, so variations in the distance between the dielectric 13 and the conductive sheet 15 are suppressed.

(Switch according to third embodiment)
FIG. 13 is a cross-sectional view of the switch 3 according to the third embodiment in a cross section corresponding to the III-III cross section in FIG. The switch 3, like the switches 1 and 2, is a capacitive pressure-sensitive switch that detects a pressing operation based on a change in the capacitance of a capacitor formed inside.

The switch 3 differs from the switch 1 in that it has an adhesive layer 20 instead of the adhesive layer 19. Further, the switch 3 is configured such that the height of the top surface of the spacing member 14, not the top surface of the dielectric 13, substantially matches the height of the top surface of the second electrode 122 disposed on the top surface of the base 11. differ. The configurations and functions of the components of the switch 3 other than the height of the top surface of the adhesive layer 20 and the spacing member 14 are the same as those of the components of the switch 2 with the same reference numerals, so a detailed description will be given here. is omitted.

Like the adhesive layer 19, the adhesive layer 20 is formed of a conductive adhesive material, fixes the dielectric 13 to the first electrode 121, and electrically connects the first electrode 121 and the dielectric 13. . The height of the adhesive layer 20 is adjusted so that the height of the upper surface of the spacing member 14 substantially matches the height of the upper surface of the second electrode 122 disposed on the upper surface of the base 11.

In the switch 3, the third height H3, which is the height from the top surface of the bottom plate 112 of the base 11 to the top surface of the spacing member 14, is the height from the top surface of the bottom plate 112 of the base 11 to the top surface of the second electrode 122. is equal to the second height H2. The third height H3 is calculated from the height H121 of the first electrode 121, the height H20 of the adhesive layer 20, the height H13 of the dielectric 13, and the height H14 of the spacing member 14. H3 = H121 + H20 + H13 + H14
It is indicated by.

FIG. 14 is a flow diagram showing the flow of the method for manufacturing the switch 3. FIG. 15 is a schematic cross-sectional view for explaining each step of the method for manufacturing the switch 2. As shown in FIG. 15(A) shows step S13 shown in FIG. 14, and FIG. 15(B) shows step S14 shown in FIG. 14. The processing shown in S21 to S22 is similar to the processing in S11 to S12 shown in FIG. 9, so a detailed explanation will be omitted here.

After the process of S22, as shown in FIG. 15(A), the spacing member 14 is placed on the surface of the suction plate P1 (step S23). The spacing member 14 is placed on a protrusion P11 formed on the surface of the suction plate P1. The spacing member 14 is arranged such that the sag 142 faces the sag 142 and the burr 143 extends in the opposite direction of the surface of the suction plate P1.

Next, as shown in FIG. 15(B), the dielectric 13 is attracted to the attraction plate P1 (step S24). The dielectric 13 is disposed above the protrusion P11 so as to cover the spacing member 14 placed on the protrusion P11, and by reducing the air pressure inside the intake port P12, The dielectric 13 placed on the protrusion P11 is attracted.

Next, the dielectric 13 is bonded to be electrically connected to the first electrode 121 (step S25). Similar to the process in S4, the collective substrate on which the adhesive member G is placed is turned upside down, and the collective substrate is heated while being placed on the suction plate P1 so that the dielectric 13 is accommodated in the recess 111. As a result, the adhesive member G is cured and a conductive adhesive layer 20 is formed. The processes shown in S26 to S29 are similar to the processes in S16 to S19 shown in FIG. 9, so a detailed explanation will be omitted here.

As described above, the switch 3 cures the adhesive layer 20 while adsorbing the dielectric 13 placed on the protrusion P11 via the spacing member 14, so that the spacing member 14 and the dielectric 13 are cured. is positioned with high accuracy based on the height of the top surface of the base 11. In the method for manufacturing the switch 3, the spacing member 14 is positioned based on the height of the top surface of the base 11 regardless of variations in the height of the burr 143 of the spacing member 14, so that the spacing member 14 and Variations in the distance between the conductive sheet 15 and the conductive sheet 15 can be suppressed.

As Example 1-10, ten switches having a configuration corresponding to switch 1 described above were prepared. The dielectric material 13 included in the switch according to Example 1-10 is barium titanate having a thickness of 0.6 mm and a relative dielectric constant of 2500, and the conductive sheet 15 is a conductive material having a thickness of 0.3 mm. It was rubber. The spacing member 14 included in the switch according to Example 1-10 had a through hole 141 formed by punching, and was arranged so that the sag 142 was located on the side of the conductive sheet 15. In addition, as Comparative Example 1-7, seven switches having the same configuration as the switch according to the example were used, except that the spacing member 14 was arranged so that the burr 143 was located on the side of the conductive sheet 15. A switch has been prepared.

The capacitance of the capacitor formed by the first electrode 121 of the switch according to Example 1-10 and Comparative Example 1-7 and the conductive sheet 15 was measured while the pressing surface 173 was not pressed. Further, the capacitance of the capacitor of each switch was similarly measured while the pressing surface 173 was pressed with a predetermined pressing force. Thereafter, a keystroke test was performed in which each switch was pressed 2 million times with a predetermined pressing force. After the keystroke test, the capacitance of each switch capacitor was similarly measured. Table 1 below shows the ratio of the capacitance after the keystroke test to the capacitance before the keystroke test of the switch according to the example. Further, Table 2 below shows the ratio of the capacitance after the keystroke test to the capacitance before the keystroke test of the switch according to the comparative example.

As shown in Tables 1 and 2, in the switches according to the comparative example, the average value of the capacitance ratio when not pressed was 4.54, indicating a large increase in capacitance. On the other hand, in the switch according to the example, the capacitance ratio when not pressed is 0.97 on average, and the capacitance remains almost unchanged. Further, in the switch according to the comparative example, the average value of the capacitance ratio when pressed is 1.06, and the capacitance is slightly increased. On the other hand, in the switch according to the example, the capacitance ratio when pressed is 1.00, and the capacitance does not change. That is, the amount of change in capacitance of the switch according to the example before and after the keystroke test is small, and the switch according to the example makes it possible to suppress changes in characteristics due to use. In addition, in the comparative example, the capacitance ratio when pressed is smaller than the capacitance ratio when not pressed is because the capacitance when pressed before the keystroke test was sufficiently higher than the capacitance when not pressed. This is because it is large.

In the switch according to the comparative example, since the burr 143 is placed on the side of the conductive sheet 15, the burr 143 digs into the conductive sheet 15 every time it is pressed, so the bottom surface of the conductive sheet 15 is deformed and unevenness occurs. In this case, the protruding portion of the bottom surface easily comes into contact with the dielectric 13, and the contact area between the dielectric 13 and the conductive sheet 15 increases. Therefore, it is considered that the capacitance of the switch according to the comparative example increased after the keystroke test. On the other hand, in the switch according to the example, since the bottom surface of the conductive sheet 15 described above is less likely to be deformed, it is considered that the capacitance hardly increased even after the keystroke test.

As an example, 48 switches were manufactured using the method for manufacturing switch 2 described above. By cross-sectional analysis of the switch according to the example, the thickness of the adhesive layer 19 and the depth of the recess 111 of each switch were measured.

FIG. 16 is a graph showing the relationship between the thickness T of the adhesive layer 19 and the depth D of the recess 111 of the switch according to the example. In FIG. 16, the correlation coefficient R between the thickness T and the depth D is approximately 0.968, indicating that there is a strong correlation between the thickness T and the depth D. That is, it was confirmed that the adhesive layer 19 of the switch 2 had a desired thickness such that the height of the upper surface of the dielectric 13 was the same as the height of the periphery of the recess 111.

It should be understood that those skilled in the art can make various changes, substitutions, and modifications thereto without departing from the spirit and scope of the invention. For example, the embodiments and modifications described above may be implemented in appropriate combinations within the scope of the present invention.

Claims (9)

a base having a recess formed therein;
a first electrode disposed on the bottom surface of the recess;
a second electrode arranged around the recess;
a dielectric body disposed within the recess and electrically connected to the first electrode;
a conductive sheet disposed above the dielectric and electrically connected to the second electrode;
a through hole is formed in the center, and an insulating spacing member that maintains a distance between the dielectric material and the conductive sheet around the through hole;
The dielectric and the conductive sheet are arranged such that a contact area between the conductive sheet and the dielectric changes depending on a pressing force that presses the conductive sheet in the direction of the dielectric,
A recess is formed on one surface of the spacing member along an outer edge of the through hole,
The spacing member is arranged such that the recess is located on the side of the conductive sheet.
A switch characterized by: The dent is a sag formed when forming the through hole by punching,
The switch according to claim 1. a frame member surrounding the conductive sheet and bonded to the base from above the spacing member;
further comprising a protective sheet that is adhered to the frame member and protects the conductive sheet by covering the conductive sheet;
The switch according to claim 1. a first terminal arranged on the outer periphery of the base and electrically connected to the first electrode;
further comprising a second terminal disposed on the outer periphery of the base and electrically connected to the second electrode;
The switch according to claim 1. The switch according to any one of claims 1 to 4, wherein the height from the bottom of the recess to the top of the dielectric is equal to the height from the bottom of the recess to the top of the second electrode. The switch according to any one of claims 1 to 4, wherein the height from the bottom of the recess to the top of the spacing member is equal to the height from the bottom of the recess to the top of the second electrode. preparing a base having a recess formed therein, a first electrode disposed on the bottom surface of the recess, and a second electrode disposed around the recess;
A dielectric electrically connected to the first electrode is arranged in the recess so that one surface of the dielectric faces the first electrode,
disposing an insulating spacing member with a through hole formed in the center on the other surface of the dielectric;
including the step of arranging a conductive sheet above the spacing member,
The dielectric and the conductive sheet are arranged such that a contact area between the conductive sheet and the dielectric changes depending on a pressing force that presses the conductive sheet in the direction of the dielectric,
A recess is formed on one surface of the spacing member along an outer edge of the through hole,
The spacing member is arranged such that the recess is located on the side of the conductive sheet.
A method for manufacturing a switch, comprising: The step of arranging the dielectric in the recess includes:
A dielectric is accommodated in the recess so as to be electrically connected to the first electrode via an uncured adhesive member,
With the dielectric fixed so that the upper surface of the dielectric has a predetermined height with respect to the upper surface of the base, the adhesive member is cured to have a desired thickness, and the dielectric is bonded to the base. forming a conductive adhesive layer electrically connected to the first electrode;
The method for manufacturing a switch according to claim 7, comprising: A protrusion extending toward the upper surface of the dielectric is formed on the other surface of the spacing member along the outer edge of the through hole,
The step of arranging the dielectric in the recess includes:
A dielectric is accommodated in the recess so as to be electrically connected to the first electrode via an uncured adhesive member,
The adhesive member is cured while the dielectric is fixed so that the upper surface of the spacing member disposed on the other surface of the dielectric has a predetermined height with respect to the upper surface of the base. forming a conductive adhesive layer having a thickness of , and electrically connecting the dielectric to the first electrode;
The method for manufacturing a switch according to claim 7, comprising:

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