JPS6164031A - Touch panel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a touch panel that detects a pressed position based on a change in capacitance.

[Technical Background of the Invention] Recently, various touch panels have been developed that use touch-sensitive keys (touch keys) to output signals based on changes in capacitance caused by human tactile fingers to detect specified positions. It has been put into practical use.

In this type of device, only an electrode is required as a contact portion with which a finger comes into contact, and a mechanical mechanism such as a conventionally known key switch is not required, so that the panel can be easily made transparent. For this reason, they are increasingly being used as information input devices in combination with display devices and the like. In this case, a transparent coordinate position detection panel is installed on the display device,
Desired information is input by pressing down on a panel position corresponding to the desired position displayed on the display device.

[Problems with the Background Art] However, in the above-mentioned device, as shown in FIGS. 9 and 10, for example, the capacitance detection electrode 2 and the lead-out electrode 3 are formed on the glass substrate 1; The electrodes 2.3 are covered with a transparent dielectric 4. In this case, connect the grounding common electrode to the case (for watches, etc.)
I'm keeping it at 5. For this reason, since electrodes 2 and 3 are formed on the same plane, it is not possible to high-density mounting of capacitive detection electrodes, that is, touch detection electrodes, and malfunction may occur if the extraction electrode part is pressed down. There was sex.

Furthermore, the panel area is limited by the case, making it difficult to increase the size.

Further, as shown in FIG. 11, the common installation electrode 11 and the touch detection electrode 12 are provided on the same substrate 13 in a staggered manner. In this case, as shown in FIG. 12, the position of depression is detected by short-circuiting the common installation electrode 11 and the touch detection electrode 12 with a human finger 14. In this case, since the common installation electrode 11, the touch detection electrode 12, and the extraction electrode 15 are arranged on the same plane, it is possible to realize a large-area panel, but the number of touch detection electrodes is increased. However, there are limits to this, and high-density mounting of touch detection electrodes is not possible, and furthermore, there is a possibility that the lead-out electrode 15 may be disconnected due to contact with a human body or the like.

[Objective of the Invention] The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide a touch panel in which touch detection electrodes can be mounted at a high density, and malfunctions and breakage of extraction electrodes can be prevented. be.

[Summary of the Invention] In order to achieve the above object, the present invention provides a plurality of touch detection openings on one surface of a substrate formed of a dielectric material and provides a grounding counter electrode, and the touch detection openings A transparent dielectric is provided on the substrate, a touch detection electrode is arranged on the other surface of the substrate at a position opposite to the touch detection opening, and a drawer is connected to the touch detection electrode on the other surface of the substrate. It is designed to provide an electrode for use.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an external view for explaining a touch panel 20 of the present invention, and FIG. 2 is a sectional view.

That is, a grounding counter electrode 22 is formed on the upper part of a substrate made of a dielectric material, such as a glass substrate 21, except for the touch detection openings 23'. The touch detection openings 23' are each made of silicon dioxide (SiO2) 23 (as a transparent dielectric) having a film thickness comparable to that of the grounding counter electrode. Further, at the bottom of the glass substrate 21, touch detection electrodes 24 and extraction electrodes 25 are provided at positions facing the touch detection openings 23' (transparent dielectrics 23). ... is formed. The grounding counter electrode 22, the touch detection electrode 24, and the extraction electrode 25 are made by depositing ITO (indium titanium oxide) on the glass substrate 21.

A method for manufacturing the touch panel 20 will be described with reference to FIGS. 3 and 4. That is, the glass substrate 21
ITO (indium titanium oxide) is formed on both sides by vapor deposition. Next, only the necessary parts on both sides are masked, and after this masking, unnecessary parts are removed by etching. In this way, as shown in FIG. 3, a touch detection opening 23' is formed on the upper surface of the glass substrate 21.
. . . A round hole is opened to form a grounding counter electrode 22, and a touch detection electrode 24 and an extraction electrode 25 are formed on the lower surface of the glass substrate 21. Among the electrodes formed in this way, the touch detection opening 23' formed by the etching process in the touch detection electrode 24 that can be touched by the human body etc. is masked leaving only the closed round hole. Silicon dioxide<S i 02 ) is applied to the touch detection opening 23' by sputtering.
A transparent dielectric material 23 . At this time, the area of each touch detection opening 23' is made to be about the same or smaller than the area of the touch detection electrode 24 facing them. For example, as shown in FIG.
... is covered by the grounding counter electrode 22, and the human body etc. comes into contact with the grounding counter electrode 22 side.
5... No change in capacitance occurs between them.

Next, the basic principle of the touch panel 20 will be explained using FIGS. 5 and 6 (a>(b)).

That is, in FIG. 5, for example, when one of the transparent dielectrics 23 is touched by the finger 31, the transparent dielectric 2
An electrode is formed by the finger 31 on the top of 3,
It becomes equivalent to FIG. 6(b), and a corresponding capacitance is generated. In addition, if the finger 31 is not in contact with the
), and the corresponding capacitance is generated. As described above, [CO=εoS/dj
The capacitance ICO changes depending on (d: distance between electrodes, area of S2 opposing electrodes, ε0: dielectric constant).

FIG. 7 illustrates a key switch circuit using the touch panel 20 of the present invention. That is, the signals from each of the touch detection electrodes 24 are supplied to the touch detection circuit 42 via the switches 41, respectively. This touch detection circuit 42 is connected to a balance circuit 43 which is adjusted to maintain a parallel state when the capacitance when a human body or the like is not in contact is supplied as a signal from the touch detection electrode 24. , and a comparison circuit 44 that compares the output of this balance circuit 43 with a reference voltage Vref. The balanced circuit 43 includes a coil 45.4
6, an oscillator 47, and an LC resonance circuit 48. The comparison circuit 44 is configured to output a "1" signal as a touch detection signal when the output from the parallel circuit 43 is higher than the reference voltage. The output of the touch detection circuit 42, that is, the output of the comparison circuit 44 is sent to the CPU.
49. The CPU 49 controls the entire system, and performs touch detection by outputting a selection signal to the decoder 50 and sequentially turning on the switches 41 to sequentially sample the outputs of the touch detection electrodes 24. The signal is supplied to the circuit 42. The above CP
U49 compares the data output to the decoder 50 with the comparison circuit 4.
Depending on whether the touch detection signal from 4 is provided,
This is to determine whether there is a touch by a human body or the like and the position of the touch.

Therefore, when a predetermined transparent dielectric 23 is touched by the human body, that is, the finger 31, a large capacitance is output from the touch detection electrode 24 facing the transparent dielectric 23. Thereby, when the switch 41 corresponding to the touch detection electrode 24 is turned on in accordance with the selection signal from the CPU 49, the signal from the electrode 24 is transmitted to the touch detection circuit 42.
supplied to Then, the output of the balance circuit 43 changes,
The voltage becomes larger than the reference voltage Vref, and a “1” signal is supplied from the comparison circuit 44 to the CPU 49 as a touch detection signal. Thereby, the CPU 49 determines the touch position from the data (selection signal) output to the decoder 50.

Note that by arranging the touch detection electrodes 24 and the transparent dielectric 23 in a high-density combination, the coordinate position detection accuracy of the touch panel 20 can be further improved.

In the above embodiment, the transparent dielectric material of the touch detection opening was formed flat, but the invention is not limited to this. As shown in FIG. 8, the dielectric material 51 such as S i 02 having a spherical upper part It may be formed by In this case, it is possible to prevent water droplets from adhering to the touch detection opening, that is, the transparent dielectric material, and prevent malfunctions due to water wetting. Also,
Although the touch detection opening was circular, it is not limited to this.
It may also be a square shape.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide a touch panel in which touch detection electrodes can be mounted in high density, and malfunctions and breakage of extraction electrodes can be prevented.

[Brief explanation of drawings]

1 to 7 are for explaining one embodiment of the present invention. FIG. 1 is an external view of a touch panel, FIG. 2 is a sectional view of the touch panel, and FIG. 3 is a part of FIG. 1. FIG. 4 is an enlarged perspective view of a part of FIG. 4, FIG. 5 and FIG. 6 are diagrams for explaining the operating principle, and FIG. 7 is a key switch circuit. FIG. 8 is a sectional view for explaining the configuration of a touch panel in another embodiment, and FIGS. 9 to 12 are diagrams for explaining the configuration of a conventional touch panel. This is a diagram. 21... Substrate, 22... Counter electrode for grounding, 23'~
...Aperture for touch detection, 23-...Transparent dielectric material,
24--Touch detection electrode, 25--Extraction electrode, 41--Switch, 42--Touch detection circuit, 44--Comparison circuit, 49--CPU, 50--
·decoder. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 9 Figure 11

Claims (1)

[Claims] A substrate formed of a dielectric material, a grounding counter electrode provided with a plurality of touch detection openings on one surface of the substrate, a transparent dielectric material provided in the touch detection openings, and a grounding counter electrode provided on one surface of the substrate. A touch detection electrode provided on the other surface of the substrate at a position opposite to the touch detection opening, and an extraction electrode provided on the other surface of the substrate and connected to the touch detection electrode. Features a touch panel.