JPH09306314A - Illumination type touch switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformize approach or contact detecting sensitivity of a finger to a switch surface. SOLUTION: A transparent comb teeth electrode 2 is formed on an upper surface of a transparent insulating substrate 1, and a transparent insulating protective plate 4 is also laminated on it, on the one hand, a light emitting part 5 is arranged below, and the transparent comb teeth electrode 2 is connected to lead wires 8a and 8b through a connecting part 7, and a CR oscillating circuit added to the transparent comb teeth electrode 2, a touch judging circuit to detect the approach or contact of a finger (f) to the transparent insulating protective plate 4 by a change in an oscillating period of the CR oscillating circuit and a control circuit to drive a load apparatus so as to be turned on and off every time when the touch judging circuit detects the approach or contact of the finger (f), are provided. A pair of transparent comb teeth electrodes 2 are formed so that both sum of a distance up to connecting parts 7a and 7b from a position where the finger (f) is approached to or contacted with the transparent insulating protective plate 4 always becomes the same in an optional approach or contact position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of an illuminated touch switch that detects the approach or contact of a finger or hand by changing the electrostatic capacitance between electrodes.

[0002]

2. Description of the Related Art Conventionally, various illuminated touch switches have been developed as switches for electric appliances such as home electric appliances. In such a switch, the switch surface emits light even in a dimly lit space where the illumination does not spread sufficiently. Touch the switch surface with your finger to turn on the electrical device.
The off operation can be done quickly and surely.

As this type of touch switch, ones having various structures for touch detection have been proposed.
Recently, a transparent insulating protective plate is provided on the surface of the switch to prevent damage to the touch detection electrodes, and even if this protective plate is formed thick to increase the strength, the capacitance between the electrodes may change. A switch that enables touch detection has been developed.

[0004]

However, the above-mentioned conventional illuminated touch switch has a problem that the detection sensitivity differs depending on the touched position on the switch surface. Hereinafter, this problem will be described with reference to FIG. FIG. 5A is a diagram showing an electrode pattern formed on the transparent insulating substrate.

Here, the electrodes are a pair of transparent comb-teeth electrodes 10.
0, and the lead wire 1 through the connecting portion 101.
02. In this switch, lead wire 1
A CR oscillation circuit (not shown) is connected to 02 to detect the change in the capacitance between the electrodes due to the finger approaching or touching the surface (touch surface) of the transparent insulating protection plate, by operating the oscillation cycle, and operating Determine that there was.

However, in such an arrangement of the electrodes 100, the detection sensitivity varies as shown in the graph of FIG. 6B depending on the position of contact with a finger or the like. That is, the detection sensitivity at the position where the comb-teeth electrode 100 is distant from the connection portion 101 is lower than that at the position near the connection portion 101. The three curves in the figure are detected by changing the threshold value of the change amount of the oscillation period, which is a criterion for determining the contact of a finger or the like (the threshold values increase in the order of curve a, a, and c). This indicates that the sensitivity is measured, and in any case, as the number of electrode patterns counted based on the position of the connection portion 101 increases, the approach of the finger is determined unless the distance from the switch surface is short. You can't.

This principle will be described with reference to the equivalent circuit diagram of FIG. In this figure, the comb-teeth electrode 100 is composed of n electrode fingers, and the position α of the electrode connected to the connection portion A is
Then, the finger approaches or contacts the protective plate above the position β of the electrode connected to the connection portion B. In the comb-teeth electrode 100, the electrical resistances r (between the electrode fingers), ra (from the connection portion A to the first electrode finger), rb are set according to the lengths thereof.
(From the connection part B to the first electrode finger), rα (up to the position α on the electrode finger), rβ (up to the position β on the electrode finger)
Therefore, the voltage V0 between both connection parts A and B is
And the voltages V1 to Vn generated across the capacitance C0 between the electrodes (between αβ) are V0>V1>V2>...> Vn.

Therefore, in this electrode 100, as the distance from the connecting portion 101 increases, the position α and the position β
It becomes difficult to detect a change in capacitance C0 between electrodes (between αβ) due to a finger approaching or contacting the upper protective plate,
The detection sensitivity decreases. The present invention has been made in view of the above circumstances, and an object thereof is to provide an illuminated touch switch in which the detection sensitivity of the approach or contact of a finger to the switch surface is uniform.

[0009]

In order to achieve the above object, the illuminated touch switch of the present invention has a pair of transparent comb-teeth electrodes covered with a transparent insulating film formed on the upper surface of a transparent insulating substrate. , A transparent insulating protective plate is further laminated thereon, and a light emitting portion is provided below the transparent insulating substrate, and each of the transparent comb-teeth electrodes has a basic structure connected to a lead wire through a connecting portion. The CR oscillation circuit added to the transparent comb-teeth electrode via the lead wire, the touch determination circuit for detecting the approach or contact of the finger with respect to the transparent insulating protection plate by the change of the oscillation cycle of the CR oscillation circuit, and the touch determination A control circuit for turning on and off the load device each time the circuit detects the approach or contact of a finger.

According to the first aspect of the present invention, the pair of transparent comb-teeth electrodes has a sum of the distances from the position where the finger approaches or contacts the transparent insulating protective plate to the connection portion, at any arbitrary approach or contact position. It is always formed to be the same. That is, the electric resistance values of the comb electrodes themselves are made to be the same at any contact position. In the CR oscillating circuit, when a finger approaches or contacts the transparent insulating protection plate, the capacitance between the electrodes decreases, so the oscillation cycle decreases. The touch determination circuit detects this change and determines the switch operation.

The transparent insulating protective plate is made of acrylic, polycarbonate or the like, the transparent comb-teeth electrode is made of indium oxide or tin oxide, and the connecting portion is made of a low resistance material such as aluminum or copper. Further, the load devices that are controlled to be turned on and off include electric devices such as air conditioners, AV devices, home appliances, and OA devices. According to a second aspect of the present invention, each of the transparent comb-teeth electrodes is composed of a common portion and a plurality of electrode fingers formed by branching from the common portion. Connect. This expands the range of positions to which the lead wires can be connected.

According to another aspect of the present invention, the control circuit controls the light emitting portion from lighting to extinguishing or from extinguishing to lighting according to ON / OFF driving of the load device. Therefore, the touch operation, the light emission from the light emitting unit, and the driving of the load device can be determined for each load device using this switch according to the usage mode. In claim 4, an EL element (electroluminescence) is caused to emit light in the light emitting portion by applying an AC voltage to the phosphor, and the surface light emitting body is simply configured.
A light emitting layer is used. This EL light emitting layer has a structure that can be easily laminated with a transparent insulating substrate on which a transparent comb-teeth electrode is formed, but it does not necessarily have to be integrated with an electrode or the like for touch detection. In addition, such a light emitting portion has a surface emission L
A backlight using an ED or a cold cathode tube can also be applied.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view and an electrode pattern diagram showing an example of the structure of the illuminated touch switch of the present invention. As shown in (a) of this touch switch SW, a transparent comb-teeth electrode 2 (transparent electrode layer) covered with a transparent insulating coating 3 is formed on the upper surface of a transparent insulating substrate 1, and transparent insulation protection is further formed thereon. While the plates 4 are laminated, the structure has a light emitting portion 5 below, so that a transparent name plate 6 can be inserted between the transparent insulating coating 3 and the transparent insulating protective plate 4.

Since the transparent insulating substrate 1, the transparent comb-teeth electrode 2, the transparent insulating coating 3, the transparent insulating protection plate 4, and the name plate 6 existing above the light emitting portion 5 are all made transparent, EL The light emitting unit 5 including a light emitting layer or the like can emit light on the surface so that characters or the like on the name plate 6 stand out in order to clearly indicate the position of the touch switch SW.

Further, a pair of transparent comb-teeth electrodes 2 (2a, 2
b) shows the connecting portions 7a, 7a, 7b as shown in FIG.
It is connected to the lead wires 8a and 8b via b, and both electrodes 2 are combined to form a touch surface. According to the present invention, the sum of both the distances from the position where the finger f approaches or contacts the transparent insulating protective plate 4 to the connecting portions 7a, 7b is set to an arbitrary approach. Alternatively, it is characterized in that it is always formed to be the same at the contact position.

That is, if the finger f contacts the position P in the figure, the distance Pa from the contact position P on the comb-teeth electrode 2a to the connecting portion 7a is Pa = y1 + x1 and the one comb-teeth electrode 2b. The distance Pb from the contact position P to the connecting portion 7b is Pb = y2 + x2. Therefore, the sum of these becomes Pa + Pb = X + Y, and this value becomes X + Y and becomes the same at any arbitrary position.

With this structure, the comb-teeth electrode 2
The electric resistance value due to (2a, 2b) is the same at any contact position and the voltage drop is the same, so the voltage across the capacitance between the electrodes 2 is also the same, and the detection sensitivity on the touch surface is uniform (FIG. 5). reference). FIG. 2 shows an illuminated touch switch S.
It is a block diagram showing an example of composition of an internal circuit of W.

Inside the touch switch SW, a CR oscillation circuit 10 is additionally connected to the transparent comb-teeth electrode 2 via lead wires 8 (8a, 8b). When the finger f approaches or directly touches the surface (touch surface) formed by the transparent insulating protection plate 4, the change in electrostatic capacitance is caused by the CR oscillation circuit 1
Since it appears as a change in the oscillation cycle of 0, the touch determination circuit 11 detects and discriminates this, and each time the approach or contact of the finger f is detected, the control circuit 12 drives the load device 13 to turn on and off.

Next, referring to FIG. 3, the touch switch SW
Will be described. When the finger f is not brought close to the transparent insulating protection plate 4 or directly touched, the electrostatic capacitance between the transparent comb-teeth electrodes 2 does not change, and the oscillation cycle of the CR oscillation circuit 10 is from power-on or reset. It is kept at Ps. However, in this state, when the finger f is brought close to or directly touches the transparent insulating protection plate 4, some of the lines of electric force between the electrodes 2 pass through the finger f and are grounded. The capacitance of the planar capacitor C composed of the electrodes 2 decreases, the time constant of the CR oscillation circuit 10 decreases,
The oscillation cycle becomes smaller.

The touch determination circuit 11 constantly determines the change amount of the oscillation cycle of the CR oscillation circuit 10 by a predetermined threshold value ΔPth.
The oscillation cycle is equal to this threshold value ΔPth.
If the above changes, the approach or contact of the finger f is determined and the control circuit 12 is activated. Here, in the touch determination circuit 11, the oscillation cycle has a predetermined threshold value ΔPth.
When the above change occurs, it is not immediately determined that the touch has been made, but the control circuit 12 is activated after waiting for a predetermined time t1. On the contrary, even if the amount of change in the oscillation period becomes smaller than the predetermined threshold value ΔPth, it is not immediately determined that the finger f has separated from the switch surface, and the finger f is waited for the predetermined time t2. By doing so, the malfunction of the switch SW is prevented.

When the control circuit 12 is operated, the load device 13 is turned on and off, and the light emitting section 5 is driven.
A drive voltage is supplied to the light source to control from turning on to turning off, or from turning off to turning on. For example, if the surface of the switch SW is touched and the touch determination circuit 11 detects this,
The control circuit 12 turns on the load device 13 and turns off the light emitting unit 5 that has been turned on. After that, if touched again in this state, the load device 13 is turned off and the light emitting unit 5 is turned on again.

Thus, the control by the control circuit 12 is
The touch operation, the lighting of the light emitting unit 5, and the driving of the load device 13 can be freely set according to each load device 13. Therefore, contrary to the above example, at the same time as detecting the touch and turning on the load device 13,
While turning on the load device 13,
The light emitting unit 5 can be turned off (displayed on the monitor).

Next, another structure of the electrode pattern will be described. The electrode pattern shown in FIG. 4 is the transparent insulating substrate 1.
Each of the upper transparent comb-teeth electrodes 2 has a common portion 21a, 21b configured as a connection portion 7a, 7b, and this common portion 2
A plurality of electrode fingers 22 formed by branching from 1a and 21b
a and 22b. That is, the common electrode portions of the comb-teeth electrodes 2a and 2b shown in FIG. 1 are configured as the connection portions 7a and 7b made of a low resistance material.

As a result, the position where the lead wires 8a and 8b are connected can be any part of the common portions 21a and 21b, and the lead wires 8a and 8b can be connected in the same direction as shown in the drawing, and the touch can be made. The configuration of the switch SW does not have to be complicated.

[0025]

As described above, according to the illuminated touch switch of the first aspect of the present invention, the pair of transparent comb-teeth electrodes are brought into contact with or brought into contact with the transparent insulating protective plate. Since the sum of both the distances from the position to the connection portion is always the same at any approaching or contacting position, the electrical resistance value by the comb-teeth electrode itself is made the same at any contacting position, A uniform detection sensitivity to the approach or contact of a finger is obtained on the entire surface.

According to the second aspect of the present invention, in each of the transparent comb-teeth electrodes, a common portion connecting a plurality of electrode fingers can be configured as a connecting portion made of a low resistance body, so that there is a range in which lead wires can be connected. spread. Therefore, it is possible to configure a touch switch having a uniform detection sensitivity with a simple structure. According to the third aspect, the touch operation on the switch, the light emission from the light emitting unit, and the driving of the load device can be determined according to the usage mode of the switch.

According to the fourth aspect, the illuminated touch switch can be constructed with a simple structure in which the EL light emitting layer is laminated on the transparent insulating substrate on which the transparent comb-teeth electrode is formed.

[Brief description of drawings]

1A is a sectional view showing a structure of an illuminated touch switch according to the present invention, and FIG. 1B is an electrode pattern diagram.

FIG. 2 is a block diagram showing an example of a configuration of an internal circuit of the illuminated touch switch according to the present invention.

FIG. 3 is a diagram illustrating a basic operation of the illuminated touch switch according to the present invention.

FIG. 4 is another electrode pattern diagram of the illuminated touch switch according to the present invention.

FIG. 5 is a diagram for explaining a problem caused by a conventional illuminated touch switch.

[Explanation of symbols]

 SW ... Illuminated touch switch 1 ... Transparent insulating substrate 2, 2a, 2b ... Transparent comb tooth electrodes 21a, 21b ... Common part 22a, 22b ... Electrode finger 4 ... Transparent insulation protection Plate 5 ... Light emitting part 7a, 7b ... Connection part 8, 8a, 8b ... Lead wire 10 ... CR oscillation circuit 11 ... Touch determination circuit 12 ... Control circuit 13 ... Load Device f ... finger

Claims (4)

[Claims] 1. A pair of transparent comb-teeth electrodes covered with a transparent insulating film are formed on the upper surface of a transparent insulating substrate, and a transparent insulating protective plate is further laminated thereon, while a light emitting section is provided below the transparent insulating substrate. Each of the transparent comb-teeth electrodes has a basic structure connected to a lead wire via a connecting portion, and a CR oscillation circuit is added to the pair of transparent comb-teeth electrodes via the lead wire. And a touch determination circuit for detecting the approach or contact of a finger with respect to the transparent insulating protection plate by the change of the oscillation cycle of the CR oscillation circuit, and a load device for each time the touch determination circuit detects the approach or contact of the finger. The pair of transparent comb-teeth electrodes includes a control circuit for driving on and off, and the sum of both distances from a position where a finger approaches or comes in contact with the transparent insulating protection plate to the connection portion is arbitrary. Approaching Illuminated touch switch characterized by being formed so that it is always the same at the rui or contact position. 2. The transparent comb-teeth electrode according to claim 1, wherein each of the transparent comb-teeth electrodes comprises a common portion and a plurality of electrode fingers formed by branching from the common portion. Illuminated touch switch, characterized in that it is configured as a part and connected to a lead wire. 3. The control circuit according to claim 1, wherein the control circuit responds to ON / OFF driving of a load device.
An illuminated touch switch, characterized in that the light emitting unit is controlled from turning on to turning off or from turning off to turning on. 4. The illuminated touch switch according to claim 1, wherein the light emitting portion is composed of an EL light emitting layer.