JPH0619935B2 - Transparent flat switch - Google Patents

Description

The present invention relates to a contact-type transparent flat switch that utilizes displacement of a transparent insulating sheet due to pressing.

[Conventional technology]

FIG. 8 is a sectional view showing a conventional transparent flat switch shown on page 8 of “Development Trend of Touch Input System and Application Development” issued by Japan Industrial Technology Center, for example.
12 to 12 are plan views or sectional views showing the respective constituent members.

In these FIGS. 8 to 10, 1 is a transparent first insulating sheet that is easily displaced in the thickness direction by stress, and 2 is a transparent conductive film and is provided on one side of the first insulating sheet 1. The movable electrode 3 is a first movable lead that is one of the signal extraction electrodes of the movable electrode 2, the fourth movable lead is the other signal extraction electrode of the movable electrode 2, and 5 is the first insulating sheet 1. , A movable electrode sheet composed of the movable electrode 2 and both movable leads 3 and 4 is shown in FIGS.
In FIG. 2, 6 is a transparent second insulating sheet corresponding to the first insulating sheet 1, and 7 is a transparent conductive film formed of a second conductive sheet.
A fixed electrode provided on one surface of the insulating sheet 6, a first fixed lead 8 which is one signal extraction electrode of the fixed electrode 7, and a second fixed electrode 9 which is the other signal extraction electrode of the fixed electrode 7. Leads 10 are insulating dot spacers formed of an insulating material and provided on the fixed electrode 7, and 11 is composed of a second insulating sheet 6, a fixed electrode 7, both fixed leads 8 and 9, and an insulating dot spacer 10. 3 shows a fixed electrode sheet.

Next, the operation will be described.

The transparent flat switch configured as shown in FIG. 8 uses a writing instrument P such as a finger or a ballpoint pen to press the first insulating sheet 1 as shown in FIG.
Since the first insulating sheet 1 and the movable electrode 2 move downward, the movable electrode 2 and the fixed electrode 7 come into contact with each other, and the transparent flat switch becomes conductive. Next, the first insulating sheet 1
When the external stress applied to the first insulating sheet 1,
The displacement of the movable electrode 2 starts to return to the original state, and finally the movable electrode 2 and the fixed electrode 7 become non-conductive, and the first insulating sheet 1 and the movable electrode 2 return to the original state.

In this way, by applying or removing external stress to the first insulating sheet 1, both electrodes 2 and 7 are brought into a conducting state or a non-conducting state, and this state can be detected by an external circuit.

Furthermore, since both electrodes 2 and 7 are configured so as to have a uniform resistance distribution, for example, as shown in FIG. 14, a transparent flat switch is connected to a constant current source S to connect both movable leads 3 and 4. The inflowing current ratio (X coordinate) and the outflowing current ratio (Y coordinate) from both fixed leads 8 and 9 are obtained, and by analog-digital converting these, the pressed position coordinates (X, Y) are obtained. It is calculated from the following formula.

Where: a: dimension between both movable leads 3 and 4 b: dimension between both fixed leads 8 and 9 I: total current i1: inflow current from first movable lead 3 i2: from second movable lead 4 Inflow current i3: outflow current from the first fixed lead 8 i4: outflow current from the second fixed lead 9 Even when the transparent flat switch is connected to a constant voltage source, the coordinates (X , Y) can be obtained.

[Problems to be solved by the invention]

In the conventional transparent flat switch, the insulating dot spacer 10 is present on the fixed electrode 7, and the insulating dot spacer 1
There was a problem in that both electrodes 2 and 7 could not come into contact with each other on and near 0, and a dead zone N (FIG. 13) was generated. Then, the insulation pitch of the transparent flat switches, that is, the pitch of the insulation dot spacers 10 is made constant, and the number of dead zones N increases as the number of divisions between the insulation dot spacers 10 increases and the mounting density increases. There was a problem.

As a measure against the increase of the dead zone N, it can be improved a little by making the shape of the insulating dot spacer 10 small, but the adhesion of the insulating dot spacer 10 to the fixed electrode 7 and a problem in manufacturing newly occur. At the same time, since the insulating dot spacer 10 exists on the fixed electrode 7 even if the shape becomes small, it cannot be a fundamental countermeasure.

In addition, since both the movable electrode and the fixed electrode employ a material such as a transparent conductive film provided with a transparent conductive film by a method such as vacuum deposition, sputtering, or ion plating, glass, etc., these costs are reduced. high,
As a result, it was also a cause of increasing the cost of the transparent flat switch itself.

The present invention has been made to solve the above problems, and it is formed into a planar shape on a transparent insulating sheet (first insulating sheet 21) by a physical film-forming method such as vacuum deposition, sputtering, or ion plating. A pressure-sensitive transparent conductive coating material having a first transparent conductive film (first movable electrode 22) deposited thereon and having a specific conductive substance dispersed in a resin on the first transparent conductive film. Of the movable electrode sheet 26 and the fixed electrode sheet 31, which are composed of a second transparent conductive film (second movable electrode 23) formed by applying in a planar manner, and transparent insulation. Sheet (second insulating sheet 27)
And the other electrode sheet having a third transparent conductive film (fixed electrode 28) formed by applying a transparent conductive coating material in which a specific conductive substance is dispersed in a resin on the surface, With a simple electrode configuration in which both electrode sheets are laminated with the second transparent conductive film and the third transparent conductive film in contact with each other, the packaging density can be easily increased and the physical cost is high. It is an object of the present invention to obtain a transparent flat switch which is highly reliable because the cost can be reduced by using only one transparent conductive film by the dynamic film forming method.

[Means for solving problems]

In order to solve the above problems, the transparent flat switch of the present invention has a structure in which one electrode is provided with a transparent conductive film on a transparent insulating sheet by a method such as vacuum deposition, sputtering and ion plating. Further, a transparent conductive coating is applied on the above, the other electrode is coated with a transparent conductive coating on a transparent insulating sheet, a spacer function is given to the above electrodes, and both electrode sheets are directly laminated. It has a configuration.

[Action]

In the transparent flat switch according to the present invention, the electrodes having the transparent conductive paint are in mechanical contact with each other when no external stress is applied, but electrically there is a large contact resistance between the electrodes. It is not conducting. On the other hand, when external stress is applied, the contact resistance between the electrodes decreases and the electrodes become conductive. The value (operating force) of the external stress that brings the conductive state is mainly based on the thickness of the transparent conductive coating, the coating state,
It changes depending on the conductivity.

〔Example〕

 An embodiment of the present invention will be described with reference to the drawings.

In FIGS. 1 to 3, reference numeral 21 denotes a transparent first insulating sheet which is easily displaced in the thickness direction due to stress, for example, a film-shaped or plate-shaped transparent insulating sheet made of plastic, glass or the like, and 22 a transparent first insulating sheet. The first sheet-shaped movable electrode made of a transparent conductive film provided on one surface of the insulating sheet 21 by a physical film-forming method such as vacuum deposition, sputtering, or ion plating, and 23 is the first movable electrode. A planar second movable electrode formed by applying a transparent conductive paint to the entire surface of the electrode 22, and 24 is one signal extraction electrode of the second movable electrode 23 (first movable electrode 22). 1 movable lead,
Reference numeral 25 is a second movable lead that faces the first movable lead and is the other signal extraction electrode, and 26 is a transparent first insulating sheet 21, a first movable electrode 22, a second movable electrode 2
3 shows a movable electrode sheet composed of the first movable lead 24 and the second movable lead 25. In addition, FIG. 1, FIG.
In FIG. 5, 27 is a transparent second insulating sheet corresponding to the first insulating sheet 21, which is made of, for example, plastic, glass or the like in a film shape or a plate shape, and 28 is made of a transparent conductive paint and is transparent. A planar fixed electrode provided on one surface of the second insulating sheet 27, and 29 a fixed electrode 28.
A first fixed lead which is one of the signal extracting electrodes, a second fixed lead 30 which faces the first fixed lead and which is the other signal extracting electrode of the fixed electrode 28, and a transparent second transparent electrode 31. 2 shows a fixed electrode sheet composed of the insulating sheet 27, the fixed electrode 28, the first fixed lead 29, and the second fixed lead 30. As shown in FIG. 1, the transparent flat switch of this embodiment is formed by laminating the movable electrode sheet 26 on the fixed electrode sheet 31. When external stress is applied to the first insulating sheet 1, no pressure is applied. The resistance RC (Fig. 6) between the electrodes 22 and 28, which was several tens KΩ or more in the state, started to decrease as shown in Fig. 7 due to external stress, and finally became 5K.
It is a stable value of about Ω. These stable electrodes 22,
The conduction state can be defined by detecting the resistance value between 28. It goes without saying that the value of 5 KΩ varies depending on the conductivity of each of the first movable electrode 22, the second movable electrode 23, and the fixed electrode 28.

By the way, the resistance value between the electrodes 22 and 28 is a contact resistance (occupying most of the resistance value between the electrodes) caused particularly by the second movable electrode 23 and the fixed electrode 28, and is caused by external stress. The value changes. That is, the second movable electrode 2
3, by providing the fixed electrode 28, pressure-sensitive characteristics are provided between the electrodes, and the second movable electrode 23 and the fixed electrode 28, which have the pressure-sensitive characteristic, are electrodes and spacers. The pressure characteristic appears uniformly everywhere.

The first movable electrode 22 is a transparent conductive film formed by a physical film-forming method using gold, silver, copper, carbon, nickel, tin, indium oxide, tin oxide, copper iodide, palladium chrome, or the like. The movable electrode 23 and the fixed electrode 28 are transparent conductive films provided by applying a transparent conductive paint in which a specific conductive substance similar to the above is dispersed in resin.

According to the above-described embodiment, since the second movable electrode 23 having a pressure-sensitive characteristic and the fixed electrode 28 are in contact with each other, uniform pressure-sensitive characteristics can be provided between the electrodes, and external Since the resistance value based on the stress value is uniquely determined, only one external stress value with respect to the switch conduction value can be specified, so that a switch with high operation reliability can be obtained. Moreover, since the first movable electrode 22 by the costly physical film forming method is provided only on the movable electrode sheet 26, the cost can be reduced.

Although the movable electrode has two layers and the fixed electrode has one layer in the above-mentioned embodiment, the movable electrode may have one layer and the fixed electrode has two layers.
It may be a digital / analog type.

〔The invention's effect〕

According to the present invention, a transparent insulating sheet is provided with a first transparent conductive film which is planarly deposited by a physical film-forming method, and a specific conductive material is provided on the first transparent conductive film. One electrode sheet constituted by a second transparent conductive film formed by planarly applying a pressure-sensitive transparent conductive paint dispersed in a resin, and a specific conductive substance on the transparent insulating sheet are coated with a resin. A second transparent conductive film and a third transparent conductive film, the second transparent conductive film having a third transparent conductive film formed by applying a transparent conductive coating material dispersed in a plane Since the transparent conductive film itself also functions as a spacer for separating the electrodes, the dead zone N can be eliminated and the mounting density can be increased. Even if you increase the, you can get the coordinate data that follows the handwriting without interruption Both can be inexpensive. Further, since the transparent conductive coating material itself has excellent scratch resistance, there is an effect that the reliability as a transparent flat switch is also increased, and a switch with high operation reliability is obtained, and the cost can be reduced.

[Brief description of drawings]

1 is a sectional view of a transparent flat switch according to an embodiment of the present invention, FIG. 2 is a plan view of the movable electrode sheet of FIG. 1, FIG. 3 is a sectional view taken along line III-III of FIG. 2, and FIG. Is a plan view of the fixed electrode sheet of FIG. 1, FIG. 5 is a sectional view taken along line VV of FIG. 4,
FIG. 6 is an equivalent circuit diagram of the transparent flat switch of the present invention, FIG. 7 is a characteristic diagram showing changes in contact resistance with respect to external stress, FIG. 8 is a sectional view of a conventional example, and FIG. 9 is a movable diagram of FIG. FIG. 10 is a plan view of the electrode sheet, FIG. 10 is a sectional view taken along line XX of FIG. 9, and FIG. 11 is a plan view of the fixed electrode sheet of FIG.
2 is a sectional view taken along the line XII-XII in FIG. 11, and FIG. 13 is a sectional view showing the operating state of the transparent flat switch shown in FIG.
FIG. 4 is an equivalent circuit diagram in which a transparent flat switch is connected to a constant current source. 21: first insulating sheet, 22: transparent conductive film, 23: transparent conductive paint, 24, 25: one pair of movable leads facing each other, 26: movable electrode sheet, 27: second insulating sheet,
28: transparent conductive paint, 29, 30: a pair of opposing fixed leads, 31: fixed electrode sheet.

Claims (1)

[Claims] 1. A transparent flat switch having a movable electrode sheet and a fixed electrode sheet, which is planarly deposited on a transparent insulating sheet by a physical film-forming method such as vacuum deposition, sputtering, or ion plating. A second transparent film which has a first transparent conductive film and which is formed by applying a pressure-sensitive transparent conductive paint in which a specific conductive substance is dispersed in a resin on the first transparent conductive film. One of the movable electrode sheet and the fixed electrode sheet, which is composed of a conductive film, and a transparent conductive paint in which a specific conductive substance is dispersed in a resin on a transparent insulating sheet. And the other electrode sheet having a third transparent conductive film formed by applying the second transparent conductive film and the third transparent conductive film in contact with each other. A transparent hula characterized by Switch.