JP2007052975A - Electrostatic capacitance type switch and its electrode structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacitance type switch device of which the manufacturing cost is low, and which can be applied in a place where an environment of high temperature and high humidity and water wetting is anticipated. <P>SOLUTION: A transparent electrode 2 composed of an inexpensive conductive polymer is installed on a transparent film 1, and the transparent electrode 2 is further covered by a transparent insulating sheet 4 which is transparent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a capacitive switch used for home appliances, industrial machines, transport machines, buildings, and the like, and an electrode structure thereof.

Conventionally, as an electrostatic capacitance type switch for detecting a change in electrostatic capacitance, for example, one disclosed in Patent Document 1 is known. The device disclosed in Patent Document 1 is provided with a transparent electrode for capacitance detection and a display element under a transparent protective film, and the capacitance at the transparent electrode is detected by detection means, and based on the detection result. The control means drives the display element. Further, this Patent Document 1 also discloses that a mask is provided on the display surface of the display element to display characters and pictures. As a result, not only a touch switch without a mechanical drive part is realized, but also the operator can be notified by the display element that the switch has been turned ON / OFF.
Japanese Patent Laid-Open No. 5-29879, paragraphs 0012-0013, 0019, FIG.

  By the way, as a material of the transparent electrode, ITO (tin-doped indium oxide) is generally used. On the other hand, instead of this, it is also possible to configure the transparent electrode with a conductive polymer such as inexpensive PEDOT / PSS (polyethylenedioxythiophene / polystyrene sulfonic acid), but PEDOT / PSS has poor water resistance, It cannot be applied in high-temperature and high-humidity environments or where water is expected to get wet.

  The present invention has been made in view of such points, and by using inexpensive PEDOT / PSS as a transparent electrode and having water resistance, it is expected to be wet and wet in a high-temperature and high-humidity environment at a low production cost. It is an object of the present invention to provide an electrode structure of a capacitance type switch that can be used in a place where it is used.

  The electrode structure of the capacitance type switch according to the present invention includes a film made of an insulating material, a transparent electrode made of a conductive polymer that is installed on the film and detects capacitance, and is in contact with at least a part of the transparent electrode. The conductive paste printed as described above, the transparent electrode, and a water-resistant first protective member that covers a part of the conductive paste are provided.

  According to the present invention, a transparent electrode that detects the proximity of an object to be detected is made of a conductive polymer, and this is covered with a transparent insulating sheet. It is possible to provide a capacitance type switch that can be applied to a place to be operated.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a perspective view showing a configuration of a capacitive switch according to the first embodiment of the present invention. 2 is an exploded perspective view of a part of FIG. 1, and FIG. 3 is a cross-sectional view taken along the line A-A 'of FIG.

  The capacitance type switch 10 includes an electrode unit 5 that detects the proximity of a detected object such as a finger, and a circuit board unit 9 that detects the capacitance detected by the electrode unit 5. The electrode portion 5 is in contact with a part of the transparent electrode 2, a film 1 made of a transparent flexible resin, a transparent electrode 2 made of PEDOT / PSS that is installed on the film 1 and detects capacitance. The conductive paste 3 is made of a silver paste printed on the surface, and the transparent electrode 2 and the first protective member 4 covering a part of the conductive paste 3 are provided. Here, the first protection member 4 is a water-resistant insulating sheet made of transparent PET, and is thermocompression bonded to the film 1 at the thermocompression bonding portion 4 a so as to surround the transparent electrode 2. The circuit board 9 includes a printed circuit board 7 having a detection circuit (not shown) that detects the capacitance detected by the transparent electrode 2, the conductive paste 3 and the circuit board 9 included in the electrode 5, and a connecting member 6a. And a water-resistant second protective member 8 made of a resin that covers a part of the electrode portion 5 and the circuit board portion 9.

  FIG. 4 is a cross-sectional view showing the manufacturing process of this capacitance type switch.

  First, (a) a transparent electrode 2 made of PEDOT / PSS is formed on a film 1 made of a transparent flexible resin, and a conductive paste 3 is printed on the film 1 so as to overlap a part of the transparent electrode 2. . Next, (b) the first protective member 4 is placed so as to cover the transparent electrode 2 and a part of the conductive paste 3, and (c) the first protective member 4 is formed so as to surround the transparent electrode 2. The film 1 is thermocompression bonded to form the electrode portion 5. (D) This electrode part 5 is connected to the connector 6 joined to the printed circuit board 7, and finally (e) the part of the conductive paste 3 not covered with the first protective member 4, the connector 6 and the printed circuit board 7. Is molded with a second protective member 8 such as a resin having water resistance to produce the switch 10.

  FIG. 5 is a circuit diagram showing the electrical configuration of the capacitance type switch.

  The electrode unit 5 detects the capacitance Cx due to the proximity of a detection object such as a finger with the transparent electrode 2 and outputs the detected capacitance Cx to the capacitance detection circuit 16 included in the circuit board unit 9. The capacitance detection circuit 16 converts the capacitance Cx detected from the transparent electrode 2 into a measurement value such as a voltage and outputs the measurement value to the comparator 17. The comparator 17 receives a measured value from the capacitance detection circuit 16 on one side, and inputs a determination voltage 18 on the other side. When the measured value exceeds the determination voltage 18, the comparator 17 outputs a switch to an external circuit (not shown).

  The effect of the capacitive switch configured as described above will be described.

  The transparent electrode 2 for detecting the object to be detected such as a finger is configured by inexpensive PEDOT / PSS, and the transparent electrode 2 having low water resistance is formed by the first protective member 4 and the second protective member 8 having water resistance. By covering, water and moisture do not affect the transparent electrode 2. As a result, it is possible to provide a capacitive switch that is low in manufacturing cost and can be used in a high-temperature and high-humidity environment or a place where wetting is expected. In addition, invention can be implemented also by using PEDOT / TsO (polyethylene dioxythiophene / toluenesulfonate) as a conductive polymer.

  FIG. 8 is a perspective view showing a configuration of a capacitive switch according to the second embodiment of the present invention. 9 is a partial perspective view of FIG. 8, and FIG. 10 is a cross-sectional view taken along the line A-A 'of FIG.

  In the capacitance type switch 10 </ b> A, the electrode portion 5 and the circuit board portion 9 </ b> A are electrically connected by an ACF (anisotropic conductive film) 19. As shown in FIG. 9, the switch is formed by forming the electrode part 5 in the same manufacturing steps (a) to (c) of the first embodiment, and (d) arranging the electrode part 5 on the printed circuit board 7. The connection portion is bonded by AFC 19, and (e) is further manufactured by molding a part of the electrode portion 5 and the printed board 7 with resin.

  In the first and second embodiments, the printed circuit board 7 is used as the circuit board on which the detection circuit 16 for detecting the electrostatic capacitance detected by the transparent electrode 2 is installed. However, as shown in FIG. The present invention can be implemented even if the electrostatic capacitance type switch 10B is configured using the flexible printed circuit board 7B having flexibility.

  In the first and second embodiments, the first protective member 4 is bonded to the film 1 by the thermocompression bonding portion 4a. However, as shown in FIG. The present invention can also be implemented by adhering 4 to the film 1 to form a capacitive switch 10C.

  In the first and second embodiments, the first protective member 4 is an insulating sheet made of PET, but a resist is directly applied to the transparent electrode 2 and the conductive paste 3 as shown in FIG. The present invention can also be implemented by forming the member 22 and configuring the capacitive switch 10D.

  FIG. 13 is a reference diagram showing an application example of the capacitive switch according to the present invention. In this capacitive switch, a design plate 31 is disposed on the electrode portion 5 as a coating material that transmits light, such as glass, and characters, figures, and the like are displayed on the back side of the electrode portion 5 from above. A display mask plate 32, a light guide plate 34 that spreads the light from the backlight light source 33 as a whole, and a light source 35 that changes its lighting state when a switch operation is performed are provided. In this switch, the light from the light guide plate 34 that spreads the light from the backlight light source 33 lifts the characters and figures on the display mask plate 32, and the position and operation of the switch can be displayed to the operator. When the operator selects a switch and a change in capacitance is detected at the electrode unit 5, the switch operation is executed by the operator by changing the lighting state of the light source 35 such as blinking. Can be informed.

1 is a perspective view of a capacitive switch according to a first embodiment of the present invention. It is a partial perspective view of FIG. It is A-A 'sectional drawing of FIG. It is sectional drawing which shows the manufacturing process of the switch. It is a circuit diagram which shows the electric constitution of the switch. It is a perspective view of the electrostatic capacitance type switch which concerns on the 2nd Embodiment of this invention. FIG. 7 is a partial perspective view of FIG. 6. FIG. 7 is a B-B ′ sectional view of FIG. 6. It is sectional drawing which shows the manufacturing process of the switch. It is sectional drawing of the electrostatic capacitance type switch which concerns on other embodiment. Furthermore, it is sectional drawing of the electrostatic capacitance type switch which concerns on other embodiment. Furthermore, it is sectional drawing of the electrostatic capacitance type switch which concerns on other embodiment. It is a reference figure which shows the application of the electrostatic capacitance type switch which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 2 ... Transparent electrode, 3 ... Conductive paste, 4 ... 1st protection member, 5 ... Electrode part, 6 ... Connector, 7 ... Printed circuit board, 8 ... 2nd protection member, 9 ... Circuit board part DESCRIPTION OF SYMBOLS 10 ... Capacitance type switch, 16 ... Detection circuit, 17 ... Comparator, 18 ... Determination voltage, 19 ... AFC, 21 ... Resist, 31 ... Design board, 32 ... Display mask board, 33 ... Light source for backlight, 34: Light guide plate, 35: Light source.

Claims (10)

A film made of an insulating material;
A transparent electrode made of a conductive polymer that is installed on the film and detects capacitance;
A conductive paste printed so as to be in contact with at least a part of the transparent electrode, and a water-resistant first protective member that covers the transparent electrode and a part of the conductive paste. Electrostatic switch type electrode structure.   2. The capacitive switch electrode structure according to claim 1, wherein the conductive polymer is PEDOT / PSS.   3. The capacitance-type switch according to claim 1, wherein the first protection member is a transparent insulating sheet, and is thermocompression bonded to the film via the transparent electrode and a conductive paste. Electrode structure.   The capacitance type according to claim 1 or 2, wherein the first protective member is a transparent insulating sheet, and is adhered to the film with an adhesive via the transparent electrode and a conductive paste. Switch electrode structure.   3. The capacitive switch electrode structure according to claim 1, wherein the first protective member is a resist.   6. The capacitive switch electrode structure according to claim 1, wherein the conductive paste is a silver paste. The electrode structure of the capacitive switch according to any one of claims 1 to 6,
A substrate provided with a detection circuit for detecting a capacitance detected by the transparent electrode;
A connection part for electrically connecting the conductive paste and the substrate;
A capacitive switch, comprising: the conductive paste, a substrate and a water-resistant second protective member that covers the connection portion.   The capacitive switch according to claim 6, wherein the substrate is a flexible printed circuit board.   The capacitive switch according to claim 7 or 8, wherein the connection portion is a connector.   9. The capacitance type switch according to claim 7, wherein the connection portion is an anisotropic conductive film.

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