JP4664824B2 - Touch switch - Google Patents

Description

  The present invention relates to a touch switch, and more particularly to an electrode configuration of a touch switch that detects a contact or proximity of a dielectric to an electrode by a change in capacitance and supplies a current to a load.

  Conventionally, touch switches have been used for operation panels of vehicles and elevators. The touch switch is a switch that detects a contact or proximity of a dielectric material such as a user with respect to an electrode of the touch switch by a change in capacitance and supplies a current to a load. Such a touch switch is generally lit in order to inform the user that the switch has been operated. For example, Patent Document 1 describes a touch switch that illuminates a switch surface by providing a light source and electrodes on the same substrate. This is a structure in which the illumination on the surface of the switch is made uniform and the depth in the switch is secured in order to improve the display quality, and a space for the optical path is secured.

  On the other hand, a structure is known in which a light source disposed on the back surface of an electrode is turned on and light from the light source is displayed through the electrode. In such a structure, an electrode needs electroconductivity and translucency, and a transparent conductive material is used (for example, patent document 2). Generally, a transparent conductive film such as an ITO film is used as such a transparent conductive material. In general, a synthetic resin sheet including a transparent insulating sheet and a transparent conductive film electrode covered with the transparent insulating sheet is used as an electrode of such a touch switch.

  A conventional touch switch using this transparent conductive film will be described with reference to FIGS. FIG. 6 is a cross-sectional view showing a configuration of a conventional touch switch using a transparent conductive film. FIG. 7 is a plan view of a conventional touch switch in the BB line direction of FIG.

  As shown in FIGS. 6 and 7, the conventional touch switch has a structure in which, for example, a transparent insulating sheet 26, a transparent conductive film 28, a display sheet 30, and a protective panel 32 are stacked, and the light source 12 is transparent. It is arranged below the insulating sheet 26. The transparent conductive film 28 is disposed on the surface of the transparent insulating sheet 26 on the side in contact with the display sheet 30. The light emitted from the light source 12 is transmitted through the transparent insulating sheet 26 and the transparent conductive film 28, and is a mark such as a character, a figure, or the like indicating the switch function formed on the display sheet 30, such as “ON”. Through the mark 14, the characters “ON” are raised on the surface of the translucent protective panel 32. As a result, an external user or the like is made aware that the switch has been operated. Since the transparent conductive film 28 transmits light from the light source 12, the shadow of the transparent conductive film 32 is not dropped on the mark 14. As a result, the user or the like can clearly recognize the “ON” display.

JP 2001-35297 A Japanese Patent Laid-Open No. 5-29879

  This transparent conductive film has a small property and a hard property. Therefore, if the synthetic resin sheet is bent at the time of manufacturing the touch switch, a large stress is generated on the transparent conductive film, and the transparent conductive film may be damaged and broken, resulting in poor conduction. Also, since transparent conductive films are generally more expensive than opaque conductive materials, the cost of manufacturing touch switch products using transparent conductive films is higher than the cost of touch switch products using opaque conductive materials. Is generally expensive. Therefore, when lighting a touch switch using an opaque conductive material that is less expensive than a transparent conductive film, the thickness of the switch does not increase and the shadow of the electrode is not formed on the switch surface, or Development of a structure that makes the shadow of the electrode inconspicuous is desired.

  An object of the present invention is to provide a touch switch in which the shadow of an electrode generated on a mark floating on the switch surface is not noticeable when the mark is lit on the switch surface by light from a light source disposed on the back surface of the opaque electrode. It is to be.

A touch switch according to the present invention detects a contact or proximity of a dielectric to an electrode by a change in capacitance, supplies a current to a load, and a light source that is controlled to be turned on when a current is supplied to the load. in touch switch comprising, a mark portion to be illuminated by the light from the electrode is disposed in front of the light source is composed of a material and a conductive non-transparent, passing to multiple light from a light source has an opening, the mark portion is formed in the display sheet disposed on the front surface of the electrode, and through the light from the plurality of openings, a plurality of openings, and one or more apertures surrounding the mark portion, And a plurality of fence-like or mesh-like openings arranged outside the opening surrounding the mark portion . In the touch switch according to the present invention, the line width of the electrode forming the opening is preferably about 0.1 mm.

In another touch switch according to the present invention, the electrode is preferably disposed on the back surface of the light-transmitting substrate. Moreover, it is preferable that the other touch switch which concerns on this invention contains a translucent protective panel in the front surface of a surface sheet .

  With the above configuration, the touch switch according to the present invention can make the shadow of the opaque electrode pattern generated on the switch surface inconspicuous, and further uses an expensive transparent electrode such as a transparent conductive film. Therefore, a touch switch that is less expensive than a touch switch using a transparent electrode can be provided.

  Further, in the touch switch according to the present invention, since the translucent substrate is disposed between the opaque electrode and the mark portion, the light incident on the translucent substrate is diffused inside the substrate and becomes opaque. Since a so-called light diffusion effect such as wrapping behind the electrode can be expected, the shadow of the electrode pattern generated on the switch surface can be made inconspicuous.

  In addition, by making the electrode shape into a thin line so as to form an opening, even if a part of the thin line is broken, it goes around the broken part and becomes conductive, so that the function as an electrode is completely impaired. Absent. Further, the protection panel provided on the electrode improves durability such as prevention of damage caused by contact of a dielectric material of a user or the like.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view of a touch switch 10 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the touch switch 10 according to an embodiment of the present invention.

  As shown in FIG. 1, the touch switch 10 includes a light source 12, a circuit board 16, an electrode 18, a display sheet 20, and a protection panel 22, and is attached to a vehicle or the like.

  The light source 12 is disposed below the circuit board 16. The light source 12 is generally an LED or a bulb lamp, but is not particularly limited as long as it emits light. Further, the number of the light sources 12 may be one or plural.

  The electrode 18 is connected to a circuit board 16 for controlling the lighting of the light source 12 and supplying a current to a load by a lead wire (not shown). A wiring circuit (not shown) is formed on the circuit board 16, and a detection circuit for detecting a change in capacitance between the electrode 18 and the ground, lighting control of the light source 12, and supply of current to the load A control circuit. The circuit board 16 is generally made of an epoxy resin or the like, but may be an inorganic material such as ceramics as long as it is a material that transmits light from the light source 12.

  The electrode 18 has a connection terminal and is connected to a lead wire (not shown) by a connector or the like. The electrode 18 can be obtained by processing a metal material such as a copper alloy, an inorganic material such as conductive ceramics, and an opaque conductive material such as a conductive synthetic resin. These materials are molded so as to have sufficient mechanical strength in handling during production and use.

  As shown in FIG. 3, the electrode 18 has an opening 24 through which light from the light source 12 passes. The opening shape of the opening 24 is preferably an opening arranged in a fence shape. By doing so, it is possible to transmit light over a wide range of the electrode 18 as compared with the case where several holes are present in the electrode 18. For example, FIG. 4A shows an electrode 18 having openings arranged in a fence shape. Behind the opening 24 of the electrode 18 (at the back of the paper) is a state in which a mark such as a character, a figure, or the like indicating a switch function drawn on the display sheet 20, for example, a mark 14 such as “ON” is inverted. Observed at. In this case, the light emitted from the light source 12 passes through the opening 24, passes through the circuit board 16, passes through the mark 14 such as “ON” drawn on the display sheet 20, and transmits light. The character “ON” is raised on the surface of 22. According to this embodiment, since the electrode 18 is formed by a thin line having a hook or stripe shape so as to form a plurality of rectangular openings, the shadow of the electrode 18 falling on the mark 14 can be made inconspicuous. As a result, the user or the like can clearly recognize the “ON” display.

  Further, as shown in FIG. 4B, the opening 24 of the electrode 18 may be a mesh-like opening. In this case, as compared with the openings arranged in a fence shape, the density of the lines of the electrodes 18 can be increased, and the lines of the electrodes 18 are arranged so as to cross in the vertical and horizontal directions so as to form a lattice shape. As a result, it is difficult to be deformed even when subjected to external force, and a structure with higher durability and sensitivity can be obtained.

  In addition to the above, the shape of the opening 24 may be a circle, a triangle, a quadrangle, other polygons, or any other shape. The opening 24 may be formed by drilling a plate-like material or by knitting a linear material.

  Further, as shown in FIG. 4C, the line of the electrode 18 can be prevented from overlapping the mark 14 such as “ON”. In this case, the lines of the electrode 18 are arranged so as to surround “O” and “N”, respectively, and form the opening 24. Thereby, the light emitted from the light source 12 passes through the openings formed so as to surround “O” and “N”, respectively, so that no shadow of the electrode 18 is formed on the mark 14.

  The aperture ratio of the electrode 18 is determined by the mechanical strength and translucency of the electrode 18. This is because when the aperture ratio increases, the mechanical strength of the electrode 18 decreases, and when the aperture ratio decreases, the translucency of the electrode 18 decreases. An opening ratio of 10% or more can be used, but it is preferably 50% or more, particularly preferably 90% or more.

  Although not shown here, the electrode 18 is connected to the circuit board 16 by a lead wire (not shown). As the lead wire, generally, a metal wire such as a copper alloy coated with a synthetic resin or the like is used. The lead wire is connected to the electrode 18 and a terminal or connector of the circuit board 16.

  The display sheet 20 disposed on the electrode 18 is a sheet on which characters, figures, and the like for the user to recognize are printed. For characters, figures, etc., for example, a mark 14 such as “ON” is displayed to display the on function of the in-vehicle air conditioner. The display sheet 20 and the electrode 18 may be bonded with an adhesive or the like, or may be fastened with screws or the like. Although the synthetic resin is generally used for the display sheet 20, a sheet of an inorganic material such as ceramics may be used. The display sheet 20 is preferably a transparent sheet for allowing the user to recognize characters, graphics, and the like. However, the display sheet 20 may be a translucent sheet, and is not limited thereto as long as the sheet has translucency. Moreover, you may color parts, such as a character and a figure, in order to make a user recognize notably from the other part of the display sheet 20, and to make it recognize. Moreover, in order to make the shadow of the shape of the thinned electrode 18 inconspicuous, portions other than characters, figures and the like of the display sheet 20 may be colored. Further, characters, figures, and the like may be printed on the protective panel 22 without using the display sheet 20.

  The protective panel 22 disposed on the display sheet 20 is a panel used for improving durability such as prevention of damage and corrosion of the display sheet 20 and the electrode 18. The protective panel 22 and the display sheet 20 may be bonded with an adhesive or the like, or may be fastened with screws or the like. When the display sheet 20 is not used, the protective panel 22 is disposed on the electrode 18 in the same manner. The protective panel 22 is preferably transparent, but may be translucent, and the protective panel 22 may be used as long as the light from the light source 12 can be transmitted. The protective panel 22 is generally preferably a synthetic resin, but an inorganic material such as ceramics may be used.

  Next, the operation of the above configuration will be described with reference to FIG. When a dielectric such as a user contacts or approaches the electrode 100 of the touch switch 10, the capacitance between the electrode 100 and the ground changes. The change in capacitance is detected by a detection circuit 110 such as a touch sensing IC on the circuit board 16, and the detection signal is transmitted to the control circuit 120. The control circuit 120 supplies current to the load, and turns on the light source 12 such as an LED. The light from the light source 12 is drawn on the display sheet 20 by passing through the circuit board 16 and illuminating the display sheet 20 through an opening 24 formed by openings arranged in a fence shape of the electrodes 18. A mark 14 such as a character or a figure is displayed. The user can see that the switch has been operated by looking at the display.

It is a perspective view of a touch switch which is an embodiment of the present invention. It is sectional drawing of the touch switch which is embodiment of this invention. It is a top view which shows the electrode shape which the opening part of the electrode arranged in the shape of a fence. It is the top view of the AA line direction of FIG. 2 of the touch switch which is embodiment which concerns on this invention, and is the figure by which the opening part of the electrode was comprised by the fence shape. It is the top view of the AA line direction of FIG. 2 of the touch switch which is other embodiment which concerns on this invention, and is the figure by which the opening part of the electrode was comprised by the mesh shape. FIG. 9 is a plan view of the touch switch according to another embodiment of the present invention in the direction of the line AA in FIG. 2, and the electrode opening portion is configured with one opening surrounding the mark portion and a mesh-like opening. FIG. It is the block diagram which showed the effect | action of the touch switch which is embodiment which concerns on this invention. It is sectional drawing of the conventional touch switch. It is a top view of the BB line direction of FIG. 6 of the conventional touch switch.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Touch switch, 12 Light source, 14 mark, 16 Circuit board, 18,100 Electrode, 20, 30 Display sheet, 22, 32 Protection panel, 24 Opening part, 26 Transparent insulating sheet, 28 Transparent conductive film, 110 Detection circuit 120 Control circuit.

Claims (4)

A contact or proximity of a dielectric to an electrode is detected by a change in capacitance, a current is supplied to the load, a light source that is controlled to light when supplying current to the load, and a mark illuminated by the light from this light source And a touch switch including:
Electrode is disposed on the front surface of the light source is composed of a material and a conductive non-transparent, has an opening for passing to multiple light from a light source,
Mark portion is formed in the display sheet disposed on the front surface of the electrode, and through the light from the plurality of openings,
The plurality of openings include one or more openings surrounding the mark portion, and a plurality of fence-like or mesh-like openings arranged outside the opening surrounding the mark portion.
A touch switch characterized by that.   2. The touch switch according to claim 1, wherein the line width of the electrode forming the opening is about 0.1 mm.   The touch switch according to claim 1, wherein the electrode is disposed on a back surface of the light-transmitting substrate.   4. The touch switch according to claim 3, further comprising a translucent protective panel on the front surface of the top sheet.

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