Electrostatic capacitive sensor

Abstract

To provide an electrostatic capacitive sensor capable of selecting the position of a detection electrode at manufacture.SOLUTION: An electrostatic capacitive sensor includes a first substrate 10, and a second substrate 20 smaller than the first substrate 10 in a plan view. The first substrate 10 includes a first base material 11 with a plate shape, and a plurality of conductive parts 12 each including a conductive part 12a disposed on the base material 11 and a conductive part 12b having a first end electrically connected to the conductive part 12a and a second end electrically connected to a terminal 13 connected to a driving circuit. The second substrate 20 includes a second base material 21 with a plate shape, and a detection electrode 23 disposed on the second base material 21, and is disposed on the first substrate 10 in a state in which the conductive part 12a of one conductive part 12 selected from the plurality of conductive parts 12 and the detection electrode 23 are in electric connection.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to capacitive sensors. [Background technology]

[0002] Patent Document 1 discloses, as an example of a capacitance sensor, a detection device including a sensor substrate on which a plurality of detection electrodes are arranged in a matrix on a first surface of the sensor substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-084604 Summary of the Invention [Problem to be solved by the invention]

[0004] The capacitance sensor described in Patent Document 1 may be combined with a display device, and may also be placed inside a product such as furniture made of wood. In this case, the capacitance sensor reacts when a user touches a symbol indicating a switch placed on the outer surface of the product. In this case, the detection electrodes do not need to be arranged in a matrix across the entire first surface of the sensor substrate; they may be located in positions corresponding to the number of symbols.

[0005] However, the position of the symbol indicating the switch differs for each product, and it is necessary to manufacture a capacitance sensor with a different detection electrode position for each product. Manufacturing a dedicated capacitance sensor for each product is difficult in terms of cost and management.

[0006] The present disclosure aims to provide a capacitance sensor in which the position of the detection electrode can be selected during manufacturing. [Means for solving the problem]

[0007] The capacitance sensor of the present disclosure includes a first substrate and a second substrate smaller than the first substrate in a plan view. The first substrate includes a plate-shaped first base material, a conductor portion disposed on the first base material, and a plurality of conductive portions each having a conductive wire portion, one end of which is electrically connected to the conductor portion and the other end of which is electrically connected to a terminal electrically connected to a drive circuit. The second substrate includes a plate-shaped second base material and a detection electrode disposed on the second base material, and is disposed on the first substrate in a state where the conductor portion of one of the plurality of conductive portions and the detection electrode are electrically connected.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0009] Hereinafter, each embodiment of the present disclosure will be described with reference to the drawings. The present disclosure is not limited by the contents described in the following embodiments. In addition, the components described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the components described below can be combined as appropriate.

[0010] Note that the disclosure is merely an example, and for those that can be easily conceived by those skilled in the art as appropriate modifications while maintaining the gist of the invention, they are naturally included in the scope of the present disclosure. Also, for the purpose of making the description clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual embodiment, but this is merely an example and does not limit the interpretation of the present disclosure. Further, in this specification and each figure, elements that are the same as those described above with respect to the previously presented figures may be assigned the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0011] The X direction, Y direction, and Z direction shown in the figure are orthogonal to each other. The Z direction corresponds to the thickness direction of the capacitance sensor 1. The +Z side (the side pointed by the arrow) in the Z direction corresponds to the front side of the capacitance sensor 1, and the opposite -Z side corresponds to the back side of the capacitance sensor 1. Also, in this specification, "plan view" means looking at the capacitance sensor 1 along the Z direction. Note that the X direction, Y direction, and Z direction are examples, and the present disclosure is not limited to these directions.

[0012] FIG. 1 is a plan view of the capacitance sensor 1 according to an embodiment of the present disclosure as viewed from the front side. FIG. 2 is a cross-sectional view of the capacitance sensor 1 taken along line II-II shown in FIG. 1.

[0013] The capacitance sensor 1 is a self-capacitance type sensor. The capacitance sensor 1 is plate-shaped and detects a detection target located on the front side. The detection target is, for example, the finger of a user. Note that the detection target may be a part of the user other than the finger, and a stylus pen or the like.

[0014] Also, the capacitance sensor 1 is disposed, for example, inside a product such as furniture. The capacitance sensor 1 is disposed at a position corresponding to a symbol such as a figure indicating a switch disposed on the outer surface of the product. The capacitance sensor 1 detects the detection target, for example, when the detection target touches the symbol. In a state where the detection target touches the symbol, the detection target does not touch the capacitance sensor

[0015] The capacitance sensor 1 includes a first substrate 10, a plurality of second substrates 20, a plurality of first connecting members 30 (corresponding to "connecting members"), and a plurality of second connecting members 40.

[0016] The first substrate 10 includes a first base material 11 and a plurality of conductive parts 12.

[0017] The first base material 11 is formed of a resin material having electrical insulation properties. The first base material 11 is plate-shaped and has a first surface 11a on the front side of the capacitance sensor 1. Further, the first base material 11 has a plurality of first pairs of holes 11b. The plurality of first pairs of holes 11b are arranged in a matrix along the X direction and the Y direction respectively. The first pair of holes 11b penetrate the first base material 11 along the Z direction.

[0018] The first pair of holes 11b have a first hole 11b1 and a second hole 11b2. The first hole 11b1 and the second hole 11b2 are arranged along a direction inclined with respect to the X direction and the Y direction.

[0019] Each of the plurality of conductive parts 12 integrally has a conductor part 12a and a lead wire part 12b.

[0020] The conductor part 12a is a through-hole that penetrates the first base material 11. The hole of the conductor part 12a (through-hole) corresponds to the first hole 11b1.

[0021] The lead wire part 12b is linear and extends from the conductor part 12a. The lead wire part 12b is disposed on the first surface 11a, the first end is electrically connected to the conductor part 12a, and the second end is electrically connected to a terminal 13 connected to the drive circuit.

[0022] A plurality of terminals 13 are arranged on the -Y side of the plurality of first pairs of holes 11b on the first surface 11a. Needless to say, the position of the terminal 13 is not limited to the above position. The drive circuit and the terminal 13 are electrically connected via a flexible substrate 2.

[0023] The plurality of conductive portions 12 are electrically isolated from each other. The plurality of wire portions 12b may be arranged in any pattern as long as they are electrically isolated from each other.

[0024] The second substrate 20 is smaller than the first substrate 10 in plan view. The second substrate 20 is disposed on the first substrate 10. The size of the second substrate 20 is such that when the second substrate 20 is disposed on the first substrate 10, in plan view, only one of the plurality of first pairs of holes 11b, i.e., the first pair of holes 11b, overlaps with the second substrate 20, and the other first pairs of holes 11b do not overlap with the second substrate 20.

[0025] The second substrate 20 includes a second base material 21, a second conductor portion 22, and a detection electrode 23.

[0026] The second base material 21 is formed of a resin material having electrical insulation properties. The second base material 21 is plate-shaped and has a second surface 21a on the front side of the capacitance sensor 1. Further, the second base material 21 has one second pair of holes 21b. The second pair of holes 21b penetrates the second base material 21 along the Z direction.

[0027] The second pair of holes 21b has a third hole 21b1 and a fourth hole 21b2. When the second substrate 20 is disposed on the first substrate 10 as described later, the third hole 21b1 overlaps with the first hole 11b1 in plan view, and the fourth hole 21b2 overlaps with the second hole 11b2 in plan view.

[0028] The second conductor portion 22 is a through hole penetrating the second base material 21. The hole of the second conductor portion 22 corresponds to the third hole 21b1.

[0029] The detection electrode 23 is disposed on the second surface 21a. The detection electrode 23 is electrically connected to the second conductor portion 22. The detection electrode 23 and the second conductor portion 22 are integral. Further, the detection electrode 23 is electrically isolated from the fourth hole 21b2.

[0030] Also, the number of the second substrates 20 is less than the number of the conductive portions 12. That is, the number of the second substrates 20 is less than the number of the conductor portions 12a (the number of the first pair of holes 11b). Therefore, the second substrate 20 can be selectively arranged at a position corresponding to one of the plurality of conductor portions 12a on the first substrate 10.

[0031] When the second substrate 20 is arranged on the first substrate 10, the position of the second substrate 20 is determined based on the position of a symbol on the outer surface of the product to which the capacitance sensor 1 is applied. Specifically, first, one of the plurality of conductive portions 12 corresponding to the position of the symbol is selected as the position of the second substrate 20.

[0032] Furthermore, the second substrate 20 is arranged on the first substrate 10 in a state where the opposite surface 21c of the second substrate 21 opposite to the second surface 21a faces the first surface 11a of the first substrate 11, and the conductor portion 12a of the one conductive portion 12 is electrically connected to the detection electrode 23. At this time, in a plan view, the third hole 21b1 and the first hole 11b1 overlap, and the fourth hole 21b2 and the second hole 11b2 overlap. Also, at this time, the conductor portion 12a of the one conductive portion 12 is electrically connected by contacting the second conductor portion 22, and is electrically connected to the detection electrode 23 via the second conductor portion 22.

[0033] Note that the second substrate 20 indicated by the dashed-dotted line in FIG. 2 shows a state where the second substrate 20 is not arranged at a position where the second substrate 20 can be arranged.

[0034] The first connecting member 30 and the second connecting member 40 connect the first substrate 10 and the second substrate 20, respectively. The first connecting member 30 and the second connecting member 40 each include bolts 31, 41 and nuts 32, 42.

[0035] The first connecting member 30 has conductivity. The first connecting member 30 penetrates the conductor portion 12a and the second conductor portion 22 (that is, penetrates the first hole 11b1 and the third hole 21b1) in a state where the second substrate 20 is disposed on the first substrate 10, and fastens the first substrate 10 and the second substrate 20. By connecting the first substrate 10 and the second substrate 20 with the first connecting member 30, the conductor portion 12a of the one conductive portion 12 and the second conductor portion 22 come into contact with each other and are electrically connected.

[0036] The second connecting member 40 has electrical insulation. The first connecting member 30 penetrates the second hole 11b2 and the fourth hole 21b2 in a state where the second substrate 20 is disposed on the first substrate 10, and fastens the first substrate 10 and the second substrate 20. The second connecting member 40 is electrically isolated from the detection electrode 23 in a state where the second substrate 20 is disposed on the first substrate 10.

[0037] Further, the capacitance sensor 1 further includes a shield electrode 50. The shield electrode 50 is disposed on the opposite surface 11c of the first substrate 11 that is opposite to the first surface 11a. The shield electrode 50 is disposed on the opposite surface 11c in a state of being electrically isolated from the conductor portion 12a. Further, the shield electrode 50 overlaps the detection electrode 23 in a plan view. The shield electrode 50 functions as an active shield that suppresses the influence on the potential of the detection electrode 23 by changing the potential in accordance with a drive signal Sg described later.

[0038] The materials of the conductive portion 12, the second conductor portion 22, the detection electrode 23, the shield electrode 50, and the first connecting member 30 are one or more metals selected from aluminum (Al), copper (Cu), silver (Ag), molybdenum (Mo), chromium (Cr), and tungsten (W), or an alloy containing one or more selected from these metal materials.

[0039] Also, in the manufacturing process of the capacitance sensor 1, as described above, the position of the second substrate 20 disposed on the first substrate 10 is determined based on the position of the symbol on the outer surface of the product to which the capacitance sensor 1 is applied. Needless to say, the position of the second substrate 20 is not limited to the position shown in FIG. 1, and is arranged to correspond to the product to which the capacitance sensor 1 is applied. For example, a plurality of second substrates 20 may be arranged in a scattered manner, a plurality of second substrates 20 may be arranged in a straight line, or may be arranged in a circular shape. That is, the position of the second substrate 20 can be recombined according to the product to which the capacitance sensor 1 is applied. The position of the second substrate 20 (detection electrode 23) can be selected during the manufacture of the capacitance sensor 1.

[0040] Next, the operation of the capacitance sensor 1 will be described.

[0041] FIG. 3 is a diagram showing an equivalent circuit of the capacitance sensor 1 and the drive circuit. FIG. 3 shows one detection electrode 23 among a plurality of detection electrodes 23. A drive signal source G and a voltage detector D are electrically connected to the detection electrode 23 via the conductive portion 12 and the second conductor portion 22. The drive signal source G and the voltage detector D are included in the drive circuit. The voltage detector D includes an integration circuit.

[0042] The drive signal source G outputs a drive signal Sg to the detection electrode 23. The drive signal Sg is an alternating rectangular wave. Based on the drive signal Sg, the charging and discharging of the detection electrode 23 are repeated. When the detection target is not close to the detection electrode 23, a current corresponding to the capacitance of the detection electrode 23 is generated by the charging and discharging of the detection electrode 23. In the voltage detector D, a detection signal Sd appears due to the current.

[0043] On the other hand, when the detection target is close to the detection electrode 23, the capacitance of the detection target causes changes in the current generated by the charging and discharging of the detection electrode 23 and the detection signal Sd that appears in the voltage detector D. The drive circuit detects that the detection target is close to the detection electrode 23 based on the change in the detection signal Sd.

[0044] The preferred embodiments of the present invention have been described above. However, the present invention is not limited to such embodiments. The content disclosed in the embodiments is merely an example, and various modifications are possible without departing from the spirit of the present invention. Appropriate modifications made without departing from the spirit of the present invention also naturally belong to the technical scope of the present invention.

[0045] For example, the capacitance sensor 1 may be a mutual capacitance type sensor.

[0046] FIG. 4 is a plan view of the first substrate 110 of the capacitance sensor 1 according to a modified example of the embodiment of the present disclosure as viewed from the front side. The first substrate 110 of this modified example is a flexible substrate having flexibility. The first substrate 110 has a main body portion 110a and a protruding portion 110b. A plurality of conductive portions 12 are arranged on the main body portion 110a in the same manner as in the above-described embodiment. The protruding portion 110b is in a strip shape and protrudes from the side on the -Y side of the main body portion 110a. A plurality of terminals 13 electrically connected to the drive circuit are arranged at the protruding end of the protruding portion 110b. Note that the second substrate 20 may also be formed of a flexible substrate. Needless to say, the position of the protruding portion 110b with respect to the main body portion 110a is not limited to the position shown in the figure.

[0047] FIG. 5 is a cross-sectional view of the capacitance sensor 1 according to a modified example of the embodiment of the present disclosure. In this modified example, the first hole 211b1 is a hole penetrating the first base material 11. Further, the conductor portion 212a does not form a through hole and is arranged around the first hole 211b1 on the first surface 11a. The first connecting member 30 electrically connects the conductor portion 212a and the second conductor portion 22 when the second substrate 20 is arranged on the first substrate 10.

[0048] In addition, with regard to other operational effects brought about by the aspects described in the present embodiment that are obvious from the description in this specification or can be appropriately conceived by those skilled in the art, they are naturally understood to be brought about by the present disclosure.

Description of Reference Numerals

[0049] 1 Capacitance sensor 10 First substrate 11 First base material 11a First surface 11c Opposite surface 12 Conductive part 12a Conductor part 12b Lead wire part 13 Terminal 20 Second substrate 21 Second base material 21a Second surface 21c Opposite surface 22 Second conductor part 23 Detection electrode 30 First connecting member (connecting member) 40 Second connecting member

Claims

1. a first substrate; a second substrate smaller than the first substrate in plan view, and the first substrate includes a plate-shaped first base material; a conductor portion disposed on the first base material, and a plurality of conductive portions each having a conductive wire portion having a first end electrically connected to the conductor portion and a second end electrically connected to a terminal electrically connected to a drive circuit; the second substrate includes a plate-shaped second base material; a detection electrode disposed on the second base material, and is disposed on the first substrate in a state where the conductor portion of one of the plurality of conductive portions is electrically connected to the detection electrode; a capacitance sensor.

2. a plurality of the second substrates are provided, and the number of the second substrates is less than the number of the conductive portions, the capacitance sensor according to Claim 1.

3. further comprising a connecting member that connects the first substrate and the second substrate, the conductor portion is a through hole penetrating the first base material, the second substrate further includes a second conductor portion that is electrically connected to the detection electrode and is a through hole penetrating the second base material, the connecting member penetrates the conductor portion of the one conductive portion and the second conductor portion, and electrically connects the conductor portion of the one conductive portion and the second conductor portion, the capacitance sensor according to Claim 1.

4. the first substrate has flexibility, the capacitance sensor according to Claim 1.

Images