JP2015130269A - Capacitance operation device and method of manufacturing capacitance operation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress inclusion of a bubble between an operation plate and an electrode sheet.SOLUTION: A capacitance operation device includes an operation plate 10 and an electrode sheet 20 as described below. The operation plate 10 forms operation surfaces 11, 12 subjected to contact operation by finger tip F. The electrode sheet 20 is configured to have electrodes 41, 42 outputting an electric signal depending on the variation of capacitance occurring between the finger tip F(operation body), and an insulating sheet 30 for holding the electrodes 41, 42. At least a part of the electrode sheet 20 is embedded in the operation plate 10 by insert molding.

Description

  The present invention relates to a capacitive operating device that is operated by contact with an operating body (for example, a user's fingertip) and a method for manufacturing the same.

  A conventional capacitive operation device includes an operation plate that is operated to be touched by a user's fingertip, and an electrode. The electrode outputs an electrical signal corresponding to the amount of change in capacitance that occurs between the electrodes. The capacitance type operation device acquires a detection value corresponding to the amount of change in capacitance generated between the electrode and the fingertip based on the electric signal, and the acquired detection value exceeds a predetermined threshold value Then, it is determined that the fingertip is in contact with the operation plate.

  In the operation device described in Patent Document 1, an electrode sheet is formed by holding the electrode on an insulating sheet, and the electrode sheet is attached to the back surface of the operation plate with an adhesive sheet so as to face the operation surface of the operation plate. The electrodes are arranged so as to.

JP 2012-79425 A

  However, in the structure described in Patent Document 1, the electrode sheet and the operation plate may be attached in a state including air bubbles. When bubbles are present in this way, the capacitances have different values, so that the determination of whether or not the detected value exceeds the threshold value varies, and the accuracy of the contact determination deteriorates.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a capacitance-type operation device that suppresses the inclusion of bubbles between an operation plate and an electrode sheet, and a method for manufacturing the same. There is.

  The invention disclosed herein employs the following technical means to achieve the above object. Note that the reference numerals in parentheses described in the claims and in this section indicate the correspondence with the specific means described in the embodiments described later, and do not limit the technical scope of the invention. .

  One of the disclosed inventions is a capacitive operation device. The operating device includes a resin-made operating plate (10) that forms an operating surface (11, 12, 13, 14) that is operated by contact with the operating body (F), and an operating surface on the opposite side of the operating body. An electrode sheet having an electrode (41, 42, 43, 44) that is positioned and outputs an electric signal corresponding to the amount of change in capacitance that occurs between the operating body and an insulating sheet (30) that holds the electrode ( 20), and at least a part of the electrode sheet is embedded in the operation plate by insert molding.

  According to this invention, since the electrode sheet is embedded in the operation plate by insert molding, the work of attaching the electrode sheet to the operation plate after resin molding with the adhesive sheet can be eliminated. Therefore, it can suppress that a bubble is contained between an operation plate and an electrode sheet. Therefore, it can suppress that a capacitance becomes a different value resulting from a bubble, and can improve the precision of contact determination by extension.

  One of the disclosed inventions is a method for manufacturing a capacitive operating device. In this manufacturing method, an electrode (41, 42, 43) that outputs an electrical signal corresponding to an amount of change in capacitance generated between the operation plate (10) that is operated by contact with the operation body (F) and the operation body. , 44) and an electrode sheet (20). Then, an adhesive application step (S20) for applying a hot-melt adhesive (HA) to the electrode sheet, and an installation step for installing the electrode sheet in a mold for resin-molding the operation plate after the adhesive application step (S30) and an injection step (S40) for injecting molten resin into the mold after the installation step.

  According to this invention, when the electrode sheet is installed in the mold and the operation plate is insert-molded, the molten resin is injected into the mold in a state where the hot-melt adhesive is applied to the electrode sheet. Insert molding. For this reason, the adhesive is melted by the heat of the molten resin, and the operation plate is formed integrally with the electrode sheet while the adhesive is solidified as the molten resin is cooled and solidified. Therefore, it is possible to suppress the inclusion of air bubbles between the operation plate and the electrode sheet, as well as to form a gap (air layer) between the operation plate and the electrode sheet due to shrinkage when the molten resin is cooled and solidified. Can be suppressed. Therefore, it can suppress that a capacitance becomes a different value resulting from a bubble or an air layer, and can improve the precision of contact determination by extension.

The front view of the electrostatic capacitance type operating device concerning one Embodiment of this invention. Sectional drawing which follows the II-II line | wire of FIG. The III arrow directional view of FIG. 2 which shows the single-piece | unit state of an electrode sheet. The flowchart explaining the manufacture procedure of the electrostatic capacitance type operating device shown in FIG. Sectional drawing which shows the state which installed the electrode sheet in the metal mold | die in the manufacturing procedure shown in FIG. FIG. Sectional drawing which shows the state which inject | poured resin in the cavity in the manufacturing procedure shown in FIG.

  Hereinafter, an embodiment of a capacitance type operating device and a manufacturing method thereof according to the present invention will be described with reference to the drawings. This operating device is mounted on a vehicle and is assembled to an instrument panel on which various meters and a display device are assembled. The operation device is arranged at a position where it can be operated from any one of the driver's seat and passenger's seat (user). As shown in FIGS. 1 and 2, the operating device includes an operating plate 10, an electrode sheet 20, and a printed wiring board 60 described below.

  The operation plate 10 is a resin-molded plate member and forms a decorative surface 10a that is visually recognized by the user. The decorative surface 10 a has a plurality of operation surfaces 11, 12, 13, and 14. On these operation surfaces 11 to 14, characters, symbols, graphics, and the like representing the setting contents of the operation target are printed. In the example illustrated in FIG. 1, the operation target is the air conditioner 100 that air-conditions the passenger compartment. For example, activation of the air conditioner 100, air volume setting, temperature setting, and the like are given as specific examples of the above setting contents. When the user touches the operation surfaces 11 to 14 with the fingertip F, a command signal for instructing the corresponding device to operate is output, and the air conditioner 100 operates according to the content of the contact operation.

  The electrode sheet 20 is positioned on the opposite side of the user with respect to the operation surface 11 and is embedded in the operation plate 10 by insert molding. The surface of the electrode sheet 20 that contacts the operation plate 10 is provided with a hot-melt adhesive HA, and the electrode sheet 20 is bonded to the operation plate 10 with the adhesive HA. The adhesive HA is mainly composed of a thermoplastic resin that is solid at normal temperature and liquid at a predetermined temperature or higher, and has translucency.

  As shown in FIG. 3, the electrode sheet 20 includes an insulating sheet 30 described below, electrodes 41, 42, 43, 44, signal wires 51, 52, 53, 54, ground wires 55, terminals 56.

  The insulating sheet 30 holds these electrodes 41 to 44, wirings 51 to 55, and terminals 56. As the material of the insulating sheet 30, a resin (for example, polyimide) having electrical insulation, flexibility and heat resistance is employed. The electrodes 41 to 44 and the wirings 51 to 55 are printed on the surface of the insulating sheet 30 opposite to the operation plate 10. The terminal 56 is formed on the surface of the insulating sheet 30 opposite to the operation plate 10.

  Each of the electrodes 41 to 44 is printed and held at a predetermined position of the insulating sheet 30 so as to face the corresponding operation surfaces 11 to 14. Transparent electrodes such as indium tin oxide are employed for the electrodes 41 to 44. Each of the signal wirings 51 to 54 is electrically connected to the corresponding electrodes 41 to 44, and is printed and held at a predetermined position on the insulating sheet 30. The ground wiring 55 is printed and held at a predetermined position on the insulating sheet 30 so as to surround the plurality of electrodes 41 to 44 and the plurality of signal wirings 51 to 54.

  One ends 51a, 52a, 53a, 54a of the wirings 51-54 are formed in a shape surrounding the corresponding electrodes 41-44. Thereby, the wirings 51 to 54 are electrically connected to the entire circumference of the electrodes 41 to 44. The other ends 51 b, 52 b, 53 b, 54 b of the wirings 51 to 54 and both ends of the grounding wiring 55 are arranged at the distal end portion of the wiring holding part 32 and are electrically connected to the terminal 56.

  In the insulating sheet 30, a part that holds the electrodes 41 to 44 is called an electrode holding part 31, and a part that holds the wirings 51 to 55 is called a wiring holding part 32. When the electrode sheet 20 is embedded in the operation plate 10 as shown in FIG. 2, the electrode sheet 20 is bent at the boundary between the electrode holding part 31 and the wiring holding part 32. That is, the entire electrode holding portion 31 is embedded in the operation plate 10, while the wiring holding portion 32 partially extends from the operation plate 10 toward the printed wiring board 60. 10 is exposed.

  Returning to the description of FIG. 2, the printed wiring board 60 is disposed on the opposite side of the operation plate 10 with respect to the electrode sheet 20. A plurality of light sources 61 and 62 are mounted on the printed wiring board 60, and these light sources 61 and 62 are arranged to face the corresponding electrodes 41 to 44.

  A light-transmitting resin member is employed for the operation plate 10, and portions of the operation surfaces 11 to 14 that are not printed are transmitted and illuminated by the light sources 61 and 62. In addition, the coating material which has light-shielding property is printed in parts other than the operation surfaces 11-14 among the decoration surfaces 10a.

  The electrodes 41 to 44 output a voltage change generated according to a change in capacitance as an electric signal. The electrical signals output from the electrodes 41 to 44 are input to a microcomputer (microcomputer 65) mounted on the printed wiring board 60. The microcomputer 65 includes a storage device that stores a program and a central processing unit that executes arithmetic processing according to the stored program. The microcomputer 65 functions as detection means 65a and contact determination means 65b described below by executing various arithmetic processes (see FIG. 2).

  A connector 66 to which the tip end portion 20a of the electrode sheet 20 is connected is mounted on the printed wiring board 60. Thereby, the terminal 56 of the electrode sheet 20 and the printed wiring board 60 are electrically connected, and the electric signal output from the electrodes 41 to 44 is input to the microcomputer 65.

  A circuit that repeatedly charges and discharges the virtual capacitor formed by the electrodes 41 to 44 is mounted on the printed wiring board 60, and the detection unit 65a counts the number of times of charging and discharging until a predetermined condition is satisfied. The count value becomes smaller as the capacitance generated between the electrodes 41 to 44 and the fingertip F increases. Therefore, based on the count value, the detection means 65a calculates a “detection value” corresponding to the amount of change in capacitance that occurs between the electrodes 41 to 44 and the fingertip F. Specifically, in the case where the count value when the fingertip F is sufficiently separated from the electrodes 41 to 44 is referred to as a reference value, the count value when the fingertip F is in the vicinity or contact position of the electrodes 41 to 44 The difference from the reference value is calculated as the detected value. When the detection value is larger than a predetermined threshold value set in advance, the contact determination unit 65b determines that the operation surface corresponding to the detection value is touched by the fingertip F.

  Next, the manufacturing method of an electrostatic capacitance type operating device will be described with reference to FIGS. FIG. 4 is a flowchart showing a manufacturing procedure of the insulating sheet 30 and the operation plate 10, and the steps shown by reference numerals S10, S20, S30, S40, S50, and S60 are sequentially performed.

  First, in the first step S <b> 10 shown in FIG. 4, the electrodes 41 to 44, the wirings 51 to 55, and the terminals 56 are formed on the insulating sheet 30. Specific examples of forming the electrodes 41 to 44 include printing on the insulating sheet 30, sputtering, vapor deposition, and the like. Specific examples of forming the wirings 51 to 55 and the terminal 56 include printing on the insulating sheet 30.

  In the next second step S <b> 20 (adhesive application step), a hot-melt adhesive HA is applied to the insulating sheet 30. Specifically, the hot-melt adhesive HA is printed on the surface of the insulating sheet 30 on the operation plate 10 side. At the time of printing in this way, the adhesive HA is in a solid state because the ambient temperature is room temperature. Thus, the electrode sheet 20 in a single state shown in FIG. 3 in which the electrodes 41 to 44, the wirings 51 to 55, the terminals 56, and the adhesive HA are provided on the insulating sheet 30 is completed. As shown in FIG. 3, a plurality of through holes 31 a are formed in the insulating sheet 30. These through holes 31 a are formed at positions avoiding the electrodes 41 to 44 and the wirings 51 to 55.

  In the next third step S30 (installation step), as shown in FIG. 5, the electrode sheet 20 is installed in a mold for resin-molding the operation plate 10. Hereinafter, this installation state will be described in detail. FIG. 5 shows a state in which the lower molds 81 and 82 and the upper mold 90 constituting the mold are closed and the cavity 90a is formed. The electrode sheet 20 is installed on the lower molds 81 and 82 in the cavity 90a. A plurality of protrusions 81a are formed on the lower molds 81 and 82, and these protrusions 81a are fitted into the through holes 31a. Thereby, the electrode sheet 20 is positioned in the cavity 90a.

  The lower molds 81 and 82 are divided into a first lower mold 81 and a second lower mold 82. As shown in FIG. 6, the first lower mold 81 has a recess 81b. In a state where the first lower mold 81 and the second lower mold 82 are in contact with each other, the recess 81b forms a through hole that penetrates the lower mold in the vertical direction. The electrode sheet 20 is fitted in the recess 81b. Therefore, the electrode sheet 20 installed in the mold is elastically deformed while being bent from the upper surface of the first lower mold 81 along the recess 81b. The tip portion 20a of the electrode sheet 20 is located below the recess 81b.

  In the next fourth step S40 (injection step), as shown in FIG. 7, high-temperature molten resin R injected from the injector at a predetermined pressure is injected into the cavity 90a. Thereby, the cavity 90a is filled with the molten resin R. The electrode sheet 20 is pressed against the lower mold by the filling pressure of the molten resin R. The adhesive HA provided on the electrode sheet 20 is melted by the heat of the molten resin R.

  In the next fifth step S50, the molten resin R is cooled and solidified in the mold until a predetermined time elapses with the molten resin R filled in the entire cavity 90a. At this time, the molten adhesive HA is also solidified. As a result, the solidified molten resin R (operation plate 10) and the electrode sheet 20 are bonded to each other by the adhesive HA, and the electrode sheet 20 is embedded in the operation plate 10. During the predetermined time required for cooling, the resin pressure from the injection machine is continuously applied to the molten resin R filled in the cavity 90a. Thereby, the molten resin R corresponding to molding shrinkage generated when the molten resin R is cooled and solidified is further added.

  In the next sixth step S60, the injection machine is separated from the mold, and the upper mold 90, the first lower mold 81, and the second lower mold 82 are removed. Then, the operation plate 10 with the electrode sheet 20 inserted is taken out of the mold, and the resin solidified by the sprue and the runner is removed from the operation plate 10.

  In the next seventh step S <b> 70, a decorative layer is printed on the operation plate 10 to form the decorative surface 10 a and the operation surfaces 11 to 14. Thereafter, the distal end portion 20 a of the electrode sheet 20 is inserted into a connector 66 provided on the printed wiring board 60, and the terminals 56 of the electrode sheet 20 are electrically connected to the printed wiring board 60. Through the above steps, the capacitive operating device shown in FIGS. 1 and 2 is manufactured.

  As described above, according to the present embodiment, the entire electrode holding portion 31 and a part of the wiring holding portion 32 in the electrode sheet 20 are embedded in the operation plate 10 by insert molding. Therefore, the electrode sheet 20 can be attached to the operation plate 10 after eliminating the work of attaching the electrode sheet 20 to the operation plate 10 after resin molding with an adhesive sheet. Therefore, it can suppress that a bubble is contained between the operation plate 10 and the electrode sheet 20. Therefore, since it can suppress that a capacitance becomes a different value resulting from a bubble, when determining the presence or absence of contact operation by comparing a detection value with a threshold value, the determination accuracy can be improved.

  Furthermore, in this embodiment, when the electrode sheet 20 is installed in the mold and the operation plate 10 is insert-molded, the hot melt adhesive HA is applied to the electrode sheet 20 and melted in the mold. Resin R is injected and insert molded. That is, after the insert molding, the surface of the electrode sheet 20 that comes into contact with the operation plate 10 is in a state in which the hot-melt adhesive HA is interposed.

  According to this, in the fourth step S40 (injection step), the adhesive plate HA is melted by the heat of the molten resin R, and the adhesive plate HA is solidified as the molten resin R is cooled and solidified. And molded integrally. Therefore, not only air bubbles can be prevented from being included between the operation plate 10 and the electrode sheet 20, but also a gap (between the operation plate 10 and the electrode sheet 20 due to shrinkage at the time of cooling and solidifying the molten resin R ( It is possible to suppress the formation of (air layer). Therefore, compared with the case where insert molding is performed without using the adhesive HA, it is possible to further suppress the inclusion of bubbles between the operation plate 10 and the electrode sheet 20 and to suppress the concern about the formation of an air layer.

  Furthermore, in this embodiment, the wirings 51 to 54 are also held by the insulating sheet 30, and the electrode holding portion 31 of the insulating sheet 30 is embedded in the operation plate 10, while a part of the wiring holding portion 32 is part of the operation plate 10. To the printed wiring board 60. For this reason, the wirings 51 to 54 electrically connected to the electrodes 41 to 44 extend from the operation plate 10 toward the printed wiring board. Therefore, as compared with the case where the wirings 51 to 54 embedded in the operation plate 10 are electrically connected to the printed wiring board 60, the electrical connection work between the wirings 51 to 54 and the printed wiring board 60 can be facilitated.

(Other embodiments)
The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made as illustrated below. Not only combinations of parts that clearly show that combinations are possible in each embodiment, but also combinations of the embodiments even if they are not explicitly stated unless there is a problem with the combination. Is also possible.

  In the embodiment described above, the adhesive HA is applied to the insulating sheet 30 in the second step S20 of FIG. 4, and the adhesive HA is interposed between the electrode sheet 20 and the operation plate 10 as shown in FIG. ing. On the other hand, the second step may be eliminated and insert molding may be performed without using the adhesive HA. Thus, even when the adhesive HA is abolished, the electrode sheet 20 can be formed without generating bubbles by insert molding so that the electrode sheet 20 is embedded in the operation plate 10 as shown in FIG. It can be attached to the operation plate 10.

  In the embodiment shown in FIG. 2, the surface (back surface) located on the opposite side of the operation plate 10 in the electrode sheet 20 is exposed from the operation plate 10. On the other hand, insert molding may be performed so that both the front surface and the back surface of the electrode sheet 20 are embedded in the operation plate 10.

  In the embodiment shown in FIG. 2, the electrodes 41 to 44 are provided on the surface (back surface) of the insulating sheet 30 located on the opposite side of the operation plate 10. On the other hand, the electrodes 41 to 44 may be provided on the surface of the insulating sheet 30. Moreover, it may replace with providing the electrodes 41-44 in the surface or back surface of the insulating sheet 30, and you may provide the electrodes 41-44 in the inside of the insulating sheet 30. FIG.

  In the embodiment shown in FIG. 2, a self-capacitance device is employed in which the capacitance of the electrodes 41 to 44 increases when the fingertip F is brought close to the electrodes 41 to 44. On the other hand, you may employ | adopt the mutual capacitance system provided with a receiving electrode with respect to each of the electrodes 41-44. In the mutual capacitance method, when the fingertip F is brought close to the electrodes 41 to 44, the electric field generated between the electrodes 41 to 44 and the receiving electrode is reduced, and the charge of the receiving electrode is reduced. The electrodes 41 to 44 or the receiving electrode outputs an electrical signal corresponding to the decrease in the electric charge.

  In the embodiment shown in FIG. 1, the present invention is applied to a capacitive operation device mounted on a vehicle, but the present invention is not limited to the one mounted on the vehicle.

  In each of the above embodiments, it is assumed that the user's fingertip F is operated while being in contact with the operation surfaces 11 to 14, and the fingertip F is used as the operating body. On the other hand, for example, the user may hold a pen-shaped operation member and operate the contact member in contact with the operation surfaces 11 to 14. In this case, an operation member other than the human body functions as the operation body. . In addition, when the user performs a contact operation on the operation surfaces 11 to 14 while wearing gloves, the gloves function as an operation body.

  In the embodiment shown in FIG. 2, the decorative surface 10a has a planar shape, but may have a curved surface shape or a partially curved shape. In the embodiment shown in FIG. 2, the operation plate 10 is a flat plate having a uniform thickness, but may be a curved plate having a uniform thickness or a plate having a non-uniform thickness.

  DESCRIPTION OF SYMBOLS 10 ... Operation plate 11, 12, 13, 14 ... Operation surface, 20 ... Electrode sheet, 30 ... Insulation sheet, 41, 42, 43, 44 ... Electrode, S30 ... Application | coating process, S40 ... Installation process, S50 ... Injection | pouring process HA ... Adhesive.

Claims (4)

A resin operation plate (10) for forming an operation surface (11, 12, 13, 14) to be contacted and operated by the operation body (F);
An electrode (41, 42, 43, 44) that is located on the opposite side of the operating body with respect to the operating surface and outputs an electrical signal corresponding to the amount of change in capacitance generated with the operating body; and An electrode sheet (20) having an insulating sheet (30) for holding the electrode;
With
At least a part of the electrode sheet is embedded in the operation plate by insert molding.   2. The electrostatic capacity type operating device according to claim 1, wherein a hot-melt adhesive (HA) is interposed on a surface of the electrode sheet that contacts the operation plate. The electrode sheet has wiring (51, 52, 53, 54) electrically connected to the electrode while being held by the insulating sheet;
An electrode holding portion (31) that is a portion for holding the electrode of the insulating sheet is embedded in the operation plate,
The electrostatic capacity type operation according to claim 1 or 2, wherein a part of the wiring holding portion (32) which is a portion for holding the wiring in the insulating sheet extends from the operation plate. apparatus. Electrodes (41, 42, 43, 44) that output electrical signals corresponding to the amount of change in capacitance generated between the operation plate (10) that is contact-operated by the operation body (F) and the operation body. An electrode sheet (20) having a capacitance-type operation device comprising:
An adhesive application step (S20) for applying a hot-melt adhesive (HA) to the electrode sheet;
After the adhesive application step, an installation step (S30) of installing the electrode sheet in a mold for resin-molding the operation plate;
After the installation step, an injection step (S40) for injecting molten resin into the mold,
The manufacturing method of the electrostatic capacitance type operating device characterized by including.

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