Capacitance sensor

Abstract

To suppress occurrences of disconnections in a capacitance sensor.SOLUTION: A capacitance sensor 1 comprises: a flexible substrate 10 integrally having a main body 11 and a protruding portion 12 that protrudes from the main body 11; a plurality of electrodes 20 disposed on the main body 11; and a plurality of conductors 30 having first ends electrically connected to the electrodes 20 and second ends positioned at protruding ends 12a of the protruding portion 12, and disposed in a continuous state from the main body 11 to the protruding portion 12.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a capacitance sensor.

Background Art

[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 and a flexible printed circuit board. The sensor substrate and the flexible printed circuit board are electrically connected via terminals.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the capacitance sensor described in Patent Document 1, the flexible printed circuit board (flexible substrate) has flexibility, but the sensor substrate does not have flexibility. Therefore, when the capacitance sensor is used in a state where the flexible substrate is repeatedly bent, stress is repeatedly applied to the connection portion (for example, the terminal portion) between the sensor substrate and the flexible substrate, and disconnection may occur at the connection portion.

[0005] An object of the present disclosure is to suppress the occurrence of disconnection in a capacitance sensor.

Means for Solving the Problems

[0006] The capacitance sensor of the present disclosure includes a flexible substrate integrally having a main body portion and a protruding portion protruding from the main body portion, a plurality of electrodes disposed on the main body portion, and a plurality of conductors having a first end electrically connected to the electrodes and a second end located at the protruding end of the protruding portion and disposed in a continuous state from the main body portion to the protruding portion.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0008] Hereinafter, each embodiment of the present disclosure will be described with reference to the drawings. The present disclosure is not limited by the content described in the following embodiments. In addition, the constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements described below can be combined as appropriate.

[0009] It should be noted that the disclosure is merely an example, and those that can be easily conceived by those skilled in the art with appropriate modifications while maintaining the gist of the invention are naturally included in the scope of the present disclosure. In addition, for the purpose of making the description clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared with the actual aspect, but this is merely an example and does not limit the interpretation of the present disclosure. Also, in this specification and each drawing, the same reference numerals may be given to the same elements as those described above with respect to the previously shown drawings, and the detailed description may be omitted as appropriate.

[0010] FIG. 1 is a plan view of the capacitance sensor 1 according to an embodiment of the present disclosure as viewed from the detection surface F1 side. FIG. 2 is a plan view of the capacitance sensor 1 shown in FIG. 1 as viewed from the opposite surface F2 side opposite to the detection surface F1. Note that the X direction and the Y direction shown in the figure are orthogonal to each other. Also, the X direction and the Y direction are each parallel to the detection surface F1.

[0011] The capacitance sensor 1 is a self-capacitance type sensor. The capacitance sensor 1 is in the form of a film and detects a detection target located on the detection surface F1 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 a stylus pen and a finger.

[0012] The capacitance sensor 1 detects the detection target in a state where the detection target is in contact with the detection surface F1. Also, the capacitance sensor 1 performs hover detection to detect the detection target even in a state where the detection target is not in contact with the detection surface F1.

[0013] The capacitance sensor 1 includes a flexible printed circuit (FPC) 10, a plurality of electrodes 20, and a plurality of conductive wires 30.

[0014] The flexible substrate 10 is in the form of a film and has flexibility. The flexible substrate 10 is transparent. In this specification, transparent means that the background on the opposite surface F2 side can be visually recognized from the detection surface F1 side in the capacitance sensor 1. The material of the flexible substrate 10 is, for example, polyethylene terephthalate and polyimide. The flexible substrate 10 integrally has a main body portion 11 and a protruding portion 12.

[0015] The main body portion 11 has a side 11a extending along a predetermined direction (corresponding to the X direction in the present embodiment) in plan view. The main body portion 11 is rectangular in plan view having the side 11a. Needless to say, the main body portion 11 is not limited to a rectangular shape in plan view. One surface of the main body portion 11 corresponds to the detection surface F1 which is the surface on the side for detecting the detection target.

[0016] The protruding portion 12 is a part that protrudes from the main body portion 11 in a plan view. The main body portion 11 and the protruding portion 12 are continuously connected without a break. The protruding portion 12 protrudes from the side 11a of the main body portion 11. The protruding portion 12 is located at a position deviated from the center in the X direction on the side 11a of the main body portion 11. In the present embodiment, the protruding portion 12 protrudes from the -X side end portion in the X direction on the side 11a.

[0017] When the protruding portion 12 is located at a position deviated from the center in the X direction of the side 11a, it is possible to suppress the protruding portion 12 from interfering with the bending of the main body portion 11 as compared with the case where the protruding portion 12 is located at the center in the X direction of the side 11a. Needless to say, the position where the protruding portion 12 protrudes from the main body portion 11 is not limited to the above position.

[0018] The protruding portion 12 is strip-shaped. The protruding portion 12 extends along the Y direction. The protruding direction length (Y direction length) of the protruding portion 12 is shorter than the width direction length (X direction length) of the protruding portion 12. Needless to say, the shape of the protruding portion 12 is not limited to the above shape. For example, the protruding direction length (Y direction length) of the protruding portion 12 may be equal to or longer than the width direction length (X direction length) of the protruding portion 12.

[0019] The protruding end portion 12a of the protruding portion 12 is connected to a drive circuit (not shown) that drives the capacitance sensor 1. A reinforcing plate 13 that suppresses the bending of the protruding end portion 12a when the protruding end portion 12a is connected to the drive circuit is attached to the detection surface F1 side of the protruding end portion 12a.

[0020] FIG. 3 is a partially enlarged view of the capacitance sensor 1 shown in FIG. 1. As shown in FIGS. 1 and 3, a plurality of electrodes 20 are arranged on the main body portion 11. Specifically, the plurality of electrodes 20 are arranged in a matrix along the X direction and the Y direction on the detection surface F1 of the main body portion 11.

[0021] The electrode 20 is a conductor layer formed by arranging a plurality of electrode lines 21 in a mesh shape in a plan view. Note that the plurality of electrode lines 21 of the electrode 20 may be arranged in a zigzag shape or a wave shape in a plan view.

[0022] The electrode wire 21 is formed of 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. Note that a conductive layer of a translucent conductive oxide such as ITO (Indium Tin Oxide) may be laminated on the electrode wire 21. Further, a blackening film, a black organic film, or a black conductive organic film combining the above-described metal materials and the conductive layer may be laminated. The above metal materials have lower resistance than translucent conductive oxides such as ITO.

[0023] Also, the plurality of electrode wires 21 are arranged in a state having an interval larger than the line width of the electrode wire 21. Thereby, it is possible to achieve low resistance and invisibility of the electrode 20.

[0024] As shown in FIG. 2, the plurality of conductive wires 30 are arranged on the opposite surface F2. The number of the conductive wires 30 is equal to the number of the electrodes 20.

[0025] The plurality of conductive wires 30 are arranged in a state of being electrically insulated from each other. Each of the plurality of conductive wires 30 has a first end electrically connected to the electrode 20 and a second end located at the protruding end portion 12a of the protruding portion 12. The plurality of conductive wires 30 are arranged in a continuous state from the main body portion 11 to the protruding portion 12. The conductive wire 30 is a continuous one of the same metal material as the above-described electrode wire 21.

[0026] A terminal (not shown) is arranged at the second end portion of the conductive wire 30. The conductive wire 30 is electrically connected to the drive circuit via the terminal. Needless to say, the arrangement of the plurality of conductive wires 30 is not limited to the arrangement shown in FIG. 2. The second end portions of the plurality of conductive wires 30 overlap the reinforcing plate 13 in plan view.

[0027] Next, the operation of the capacitance sensor 1 will be described.

[0028] FIG. 4 is a diagram showing an equivalent circuit of the capacitance sensor 1 and the drive circuit. In FIG. 4, one of the plurality of electrodes 20 is shown. A drive signal source G and a voltage detector D are electrically connected to the electrode 20 via a conductive wire 30. The drive signal source G and the voltage detector D are included in the drive circuit. The voltage detector D includes an integration circuit.

[0029] The drive signal source G outputs a drive signal Sg to the electrode 20. The drive signal Sg is an AC rectangular wave. Based on the drive signal Sg, the charging and discharging of the electrode 20 are repeated. When the detection target is not in contact (or proximity) with the electrode 20, a current corresponding to the capacitance of the electrode 20 is generated by the charging and discharging of the electrode 20. In the voltage detector D, a detection signal Sd appears due to the current.

[0030] On the other hand, when the detection target is in contact (or proximity) with the electrode 20, the capacitance of the detection target causes a change in the current generated by the charging and discharging of the electrode 20 and the detection signal Sd that appears in the voltage detector D. The drive circuit detects that the detection target is in contact (or proximity) with the electrode 20 based on the change in the detection signal Sd.

[0031] As described above, the flexible substrate 10 has flexibility, and the main body portion 11 and the protruding portion 12 are integrated. In addition, the plurality of conductive wires 30 are arranged in a continuous state from the main body portion 11 to the protruding portion 12. Therefore, even when the capacitance sensor 1 is used in a state where the flexible substrate 10 is repeatedly bent or continuously bent, since the main body portion 11 and the protruding portion 12 are integrated, stress generated in the flexible substrate 10 at the boundary between the main body portion 11 and the protruding portion 12 is concentrated. It is suppressed. In addition, the flexible substrate 10 has flexibility as a whole. Therefore, disconnection of the plurality of conductive wires 30 is suppressed. Therefore, the occurrence of disconnection in the capacitance sensor 1 can be suppressed.

[0032] 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 gist of the present invention. Appropriate modifications made without departing from the gist of the present invention naturally belong to the technical scope of the present invention.

[0033] For example, the plurality of electrodes 20 may be a planar transparent conductor layer. In this case, the material of the electrode 20 is a conductive material having translucency such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), IGO (Indium Gallium Oxide), and IGZO (Indium Gallium Zinc Oxide).

[0034] Further, the flexible substrate 10 and the electrode 20 may not be transparent and may have light-shielding properties. In this case, the material of the electrode 20 is, for example, copper.

[0035] Further, the protruding portion 12 may be located at the center in the X direction on the side 11a, or may be located at a portion other than the side 11a on the periphery of the main body portion 11. Further, the flexible substrate 10 may have two or more protruding portions 12. Further, the side 11a may be curved.

[0036] Also, 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 that can be appropriately conceived by those skilled in the art, they are naturally understood to be brought about by the present disclosure.

Explanation of Reference Numerals

[0037] 1 Capacitive sensor 10 Flexible substrate 11 Main body portion 11a Side 12 Protruding portion 12a Protruding end portion 20 Electrode 30 Conductive wire

Claims

1. A flexible substrate integrally having a main body portion and a protruding portion protruding from the main body portion, a plurality of electrodes disposed on the main body portion, a plurality of conductive wires having a first end electrically connected to the electrode and a second end located at a protruding end of the protruding portion and disposed in a continuous state from the main body portion to the protruding portion, and a capacitance sensor.

2. The flexible substrate is transparent, the electrode is in a mesh shape, The capacitance sensor according to claim 1.

3. The flexible substrate and the electrode are transparent, The capacitance sensor according to claim 1.

4. The main body portion has a side extending in a predetermined direction in plan view, the protruding portion protrudes from a position deviated from the center in the predetermined direction on the side, The capacitance sensor according to claim 1.

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