JPH09306315A - 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 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 electrode 2 is connected to lead wires 8 through connecting parts 7, and a CR oscillating circuit added to the transparent 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. The transparent insulating protective plate 4 is formed by changing its thickness according to a distance from the connecting parts 7 in response to arrangement of the transparent electrode 2 so that a variation in an oscillating period of the CR oscillating circuit when the finger (f) is approaced to or contacted with it becomes uniform over the whole of this surface.

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, in order to prevent damage to the touch detection electrodes, a transparent insulating protective plate is provided on the switch surface. Furthermore, by forming this protective plate thicker, the capacitance between the electrodes can be increased to increase the strength. A touch sensor has been developed according to the change.

[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. 6A 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). Although the sensitivity is measured, in any case, as the distance from the switch surface is not short as the number of electrode patterns counted based on the position of the connecting portion 101 increases, the approach of the finger is determined. 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 electrode fingers), ra (from the connecting portion A to the first electrode finger), r
Since it has b (from the connection portion B to the first electrode finger), rα (up to the position α on the electrode finger), and rβ (up to the position β on the electrode finger), the voltage V between both connection portions A and B is
0 and the voltages V1 to Vn generated across the capacitance C0 between the electrodes (between αβ) are V0>V1>V2>...> Vn
Becomes

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 transparent electrode covered with a transparent insulating film formed on the upper surface of a transparent insulating substrate, and further on the transparent electrode. While a transparent insulating protective plate is laminated on the transparent insulating substrate, a light emitting part is provided below the transparent insulating substrate, and a transparent electrode is connected to a lead wire through a connecting part to form a basic structure, which is added to the transparent electrode through a lead wire. A CR oscillator circuit, a touch determination circuit that detects the approach or contact of a finger with respect to the transparent insulating protective plate by the change of the oscillation cycle of the CR oscillator circuit, and A control circuit for driving the device on and off is provided, and in the claim 1, the transparent insulating protection plate has an amount of change in the oscillation cycle of the CR oscillation circuit when a finger approaches or contacts the entire surface of the transparent insulating protection plate. To be uniform, made to correspond to the thickness of the arrangement of the transparent electrode, it is formed by changing the distance from the connection portion.

When a finger approaches or contacts the transparent insulating protection plate, the capacitance between the electrodes decreases and the oscillation cycle of the CR oscillation circuit decreases. Therefore, this change is detected by the touch determination circuit and the switch is detected. Determine the operation. The transparent insulating protective plate is made of acrylic, polycarbonate, or the like, the transparent 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.

In the second aspect, since the transparent electrode is formed by combining the comb-teeth electrodes, it is possible to increase the area of the touch surface with a simple structure. In the third aspect, the control circuit controls the light emitting unit 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.

According to a fourth aspect of the present invention, an EL light emitting layer is used in the light emitting section, which makes an EL element (electroluminescence) emit light by applying an AC voltage to the phosphor, thereby simply forming a surface light emitter. This EL light emitting layer has a structure that can be easily laminated with a transparent insulating substrate on which a transparent electrode is formed, but it does not necessarily have to be integrated with an electrode or the like for touch detection. Further, a surface emitting LED, a backlight using a cold cathode tube, or the like can be applied to such a light emitting unit.

[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 electrode 2 (transparent electrode layer) covered with a transparent insulating film 3 is formed on the upper surface of a transparent insulating substrate 1, and a transparent insulating protective plate 4 is further formed thereon. On the other hand, while having a structure in which the light emitting portion 5 is provided below, the transparent name plate 6 can be inserted between the transparent insulating coating 3 and the transparent insulating protective plate 4.

As shown in (b), the transparent electrode 2 is connected to the lead wire 8 via the connecting portion 7, and here,
The transparent electrode 2 is formed by combining a pair of comb-teeth electrodes.
The present invention is characterized in that the transparent insulating protection plate 4 has a structure in which the thickness is changed.
In accordance with the distance from the connecting portion 7. That is, if the transparent electrode 2 is arranged as shown in (b), the resistance value of the electrode itself increases as the distance from the connecting portion 7 increases, so that the thickness of the transparent insulating protective plate 4 is correspondingly increased. Is thinned, and conversely, the thickness of the protective plate 4 is made thicker toward the connecting portion 7. By doing so, uniform detection sensitivity can be obtained (described later).

Above the light emitting portion 5, a transparent insulating substrate 1, a transparent electrode 2, a transparent insulating coating 3, a transparent insulating protective plate 4,
Since the name plate 6 is made entirely transparent, E
The light emitting unit 5 including the L light emitting layer or the like can emit light on the surface so that characters or the like on the name plate 6 are exposed in order to clearly indicate the position of the touch switch SW. FIG. 2 is a block diagram showing an example of the configuration of the internal circuit of the illuminated touch switch SW.

A CR oscillation circuit 10 is additionally connected to the transparent electrode 2 via a lead wire 8 inside the touch switch SW. Since the change in the capacitance when the finger f approaches or directly touches the surface (touch surface) formed by the transparent insulating protection plate 4 appears as a change in the oscillation cycle of the CR oscillation circuit 10, This is detected and discriminated by the touch determination circuit 11, 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.

In the present invention, the thickness of the transparent insulating protection plate 4 is changed as described above, but this change causes CR oscillation when the finger f approaches or contacts the surface of the protection plate 4. The change amount of the oscillation period of the circuit 10 is set to be uniform. Next, together with FIG. 3, the touch switch S
The basic operation of W will be described. When the finger f is not brought close to the transparent insulating protection plate 4 or directly touched, the capacitance between the transparent electrodes 2 does not change, and the oscillation cycle of the CR oscillation circuit 10 is
It has been kept at Ps since power-on or reset.

However, in this state, when the finger f is brought close to or directly touches the transparent insulating protection plate 4, a part of the line of electric force between the electrodes passes through the finger f and is grounded. The capacitance of the planar capacitor C formed by the electrodes 2 decreases, the time constant of the CR oscillation circuit 10 decreases, and the oscillation cycle becomes shorter. The touch determination circuit 11 is always C
Since the amount of change in the oscillation cycle of the R oscillator circuit 10 is compared with a predetermined threshold value ΔPth, if the oscillation cycle changes more than this threshold value ΔPth, the approach or contact of the finger f is determined. , Activates the control circuit 12.

In this case, the touch determination circuit 11 does not determine that a touch has been made immediately when the oscillation cycle changes by exceeding a predetermined threshold value ΔPth, and waits for a predetermined time t1 before performing control. The circuit 12 is operated. 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 can be prevented.

When the control circuit 12 operates, the load device 13
Is turned on and off, and a drive voltage is supplied to the light emitting section 5 to control from turning on to turning off or from turning off. For example, when 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. Contrary to the above example, the light emitting unit 5 is turned on at the same time when the load device 13 is turned on by detecting a touch, while the load device 13 is turned off and the light emitting unit 5 is turned on.
Can also be turned off (monitor display).

Next, another shape of the transparent insulating protection plate 4 will be described with reference to the schematic views of FIGS. FIG. 4 shows a case where the transparent electrode 2 is composed of two pairs of comb-teeth electrodes as shown in (b). Even in this case, the transparent insulating protective plate 4
As shown in the cross-sectional view of (a), the thickness of the is thin according to the shape of the transparent electrode 2 as the distance from the connecting portion 7 increases.

Further, FIG. 5 shows a case where the transparent electrode 2 is formed in a circular shape as shown in (b) and a rectangular shape as shown in (d). Even in such a case, the transparent insulation protection plate 4
In order to make the detection sensitivity uniform, (a) has a conical cross section and (c) has a pyramidal cross section.

[0024]

As described above, according to the illuminated touch switch of the first aspect of the present invention, the thickness of the transparent insulating protection plate is made to correspond to the arrangement of the transparent electrodes, and the thickness of the transparent insulating protection plate is changed from the connecting portion. If the structure is changed according to the distance, the entire switch surface can have uniform detection sensitivity to the approach or contact of the finger.

According to the second aspect, since the transparent electrode can be formed by the comb-teeth electrode, a complicated connection is not required, and the area of the touch surface can be increased 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 configured with a simple structure in which the EL light emitting layer is laminated with the transparent insulating substrate on which the transparent 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 a diagram showing another structure of the illuminated touch switch according to the present invention.

FIG. 5 is a diagram showing another structure of the illuminated touch switch according to the present invention.

FIG. 6 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 ... Transparent electrode 4 ... Transparent insulating protective plate 5 ... Light emitting part 7 ... Connection part 8 ... Lead wire 10 ...・ CR oscillation circuit 11 ・ ・ ・ Touch judgment circuit 12 ・ ・ ・ Control circuit 13 ・ ・ ・ Load device f ・ ・ ・ Finger

Claims (4)

[Claims] 1. A transparent electrode covered with a transparent insulating film is formed on the upper surface of a transparent insulating substrate, and a transparent insulating protective plate is laminated on the transparent electrode, while a light emitting portion is provided below the transparent insulating substrate. It has a basic structure in which a transparent electrode is connected to a lead wire via a connecting portion, and a CR oscillation circuit is added to the transparent electrode via the lead wire, and the CR oscillation circuit changes its oscillation cycle to make it transparent. The touch protection circuit includes a touch determination circuit that detects the approach or contact of a finger with respect to the insulating protection plate, and a control circuit that drives the load device to turn on and off each time the touch determination circuit detects the approach or contact of the finger. The thickness of the insulating protection plate is made to correspond to the arrangement of the transparent electrodes so that the amount of change in the oscillation cycle of the CR oscillation circuit becomes uniform when a finger approaches or contacts the entire surface. An illuminated touch switch, wherein the illuminated touch switch is formed by changing the distance from the connection portion. 2. The illuminated touch switch according to claim 1, wherein the transparent electrode is formed by combining comb electrodes. 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.