JPH04345714A - Flat switch - Google Patents

Abstract

PURPOSE:To provide a flat switch having high resolving power which can extremely reduce a blind sector region with simple constitution, whose durability is high. CONSTITUTION:A first conductive film 22 is formed on the surface of a first insulating sheet 21. A second conductive film 28 is formed on the surface of a second insulating sheet 27 arranged opposingly to the first insulating sheet 21. Insulating projections 31 as a plurality of microdot spacers function as spacers to electrically and physically separate the first conductive film 22 and the second conductive film 28 from each other are formed on the second conductive film 28. A lubricating layer 23 whose coefficient of friction is smaller than the first conductive film 22 is formed on the first conductive film 22.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat switch, and more particularly, to a transparent flat switch whose contacts are opened and closed by displacing an electrode sheet by a pen touch, for example.

0002

BACKGROUND OF THE INVENTION Conventionally, transparent flat switches of this type have been manufactured, for example, in P. 170. 6 to 12 show a conventional flat switch, and in the figures, 1 is a transparent first insulating sheet that can be easily displaced in the thickness direction by stress, and 2 is the surface of this first insulating sheet 1. A movable electrode film made of a transparent conductive film formed with a uniform thickness over the entire surface, 3 is this movable electrode film 2
A first movable lead, which is one signal extraction electrode electrically connected to the movable electrode film 2, is formed on one side end of the movable electrode film 2. Reference numeral 4 denotes a second movable side lead which is the other signal extraction electrode electrically connected to the movable electrode film 2, and is formed on the other end of the movable electrode film 2. Reference numeral 5 denotes a movable electrode sheet that is constituted by the first insulating sheet 1, the movable electrode film 2, and the first and second movable leads 3 and 4.

6 is a transparent second insulating sheet placed opposite to the first insulating sheet 1; 7 is a transparent second insulating sheet 6 having a uniform thickness over the entire surface of the second insulating sheet 6 facing the first insulating sheet 1; The fixed electrode film made of a transparent conductive film formed above, 8 is a first fixed side lead which is one signal extraction electrode electrically connected to this fixed electrode film 7. It is formed on one end of the movable lead 3 and is arranged perpendicularly to the first and second movable leads 3 and 4. Reference numeral 9 denotes a second fixed side lead which is the other signal extraction electrode electrically connected to the fixed electrode film 7, and is formed on the other side end of the fixed electrode film 7, and is connected to the first and second electrodes. Movable side lead 3,
It is arranged perpendicularly to 4. Reference numeral 10 denotes a fixed electrode sheet composed of the second insulating sheet 6, the fixed electrode film 7, and the first and second fixed leads 8 and 9.

Reference numeral 11 denotes a plurality of insulating protrusions provided on the fixed electrode film 7 in a matrix shape at regular intervals in the horizontal direction (X direction) and the vertical direction (Y direction), which connect the movable side electrode film 2 and the fixed side. It is placed between the electrode film 7 and functions as a spacer to electrically and physically separate both the electrode films 2 and 7,
It has a conical shape with a bottom diameter of 150 to 500 μm and a height of about 10% of this diameter, and is made of an insulating material such as silicone, acrylic, polyester, or urethane resin.

Next, a method of using the flat switch constructed in this manner will be explained. First, when turning on the switch, as shown in FIG. 11, when the first insulating sheet 1 is pressed with a writing instrument P such as a finger or a ballpoint pen, the movable electrode film 2 moves downward together with the first insulating sheet 1 and is fixed. first and second movable leads 3 in contact with the electrode film 7;
4 and the first and second fixed-side leads 8 and 9 are energized via the movable-side electrode film 2 and the fixed-side electrode film 7.

When the switch is released, the pressing force by the writing instrument P is removed, that is, when the external stress applied to the first insulating sheet 1 decreases, the elastic force of the first insulating sheet 1 returns to its original state. Eventually, the movable electrode film 2 and the fixed electrode film 7 become non-conductive, and the first insulating sheet 1 and the movable electrode film 2 return to their original states.

In this way, by applying or removing external stress to the first insulating sheet 1, the movable electrode film 2
The switch state can be made into a conductive state or a non-conductive state between the fixed electrode film 7 and the fixed electrode film 7, and the switch state can be determined by detecting this state by an external circuit. That is, as shown in FIG. 12, the first and second movable leads 3 and 4 are connected to a constant current source S or a constant voltage source, the first and second fixed leads 8 and 9 are grounded, first and second movable leads 3;
The coordinates (X, Y) can be obtained by the following equations (1) to (3).

X=(i2/I)×a (1) Y=(
i4/I)×b (2) I=i1+i
2=i3+i4 (3)

[0009] Above (
In equations 1) to (3), i1 is the first movable lead 3
i2 is the current flowing into the second movable lead 4, i3 is the current flowing out from the first fixed lead 8, i4
is the outflow current from the second fixed lead 9, a is the distance (dimension) between the first and second movable leads 3 and 4, and b is the first
and the distance (dimension) between the second fixed leads 8 and 9.

0010

However, in the transparent flat switch configured as described above, since the conical insulating protrusion 11 is provided on the fixed electrode film 7, the insulating protrusion 11 and its In the vicinity, the movable electrode film 2 and the fixed electrode film 7 cannot be connected, and a dead zone region E inevitably exists as shown in FIG. 11. Even if one tries to make the dead zone E as small as possible in order to obtain a high-resolution flat switch, current screen printing can only make the diameter about 100 μm at most, making it impossible to obtain high resolution.

In recent years, in order to further reduce the diameter of the insulating protrusions 11, instead of screen printing, a photoresist material is applied, and the photoresist material is exposed, developed, and washed, leaving only the necessary parts and forming a plurality of insulating protrusions. A microdot spacer method for forming the protrusions 11 has been considered. According to this microdot spacer method, 4
It has become possible to obtain high resolution of ~5 lines. However, when writing, that is, when the first insulating sheet 1 is pressed by the writing instrument P, the insulating protrusions 11, which are microdot spacers, peel off, causing a new problem in that accurate pressed coordinates cannot be detected. Ta. This invention has been made in view of the above-mentioned problems, and an object thereof is to obtain a high-resolution flat switch with a simple structure, which can extremely reduce the dead zone area, and which has high durability.

0012

[Means for Solving the Problems] A flat switch according to the present invention includes a first insulating sheet, a second insulating sheet disposed opposite to the first insulating sheet, and a second insulating sheet in the first insulating sheet. a first conductive film formed on the opposing surface of the insulating sheet; a second conductive film formed on the opposing surface of the first insulating sheet in the second insulating sheet; A plurality of insulating protrusions are distributed on the second conductive film, and a lubricating layer having a coefficient of friction smaller than that of the first conductive film is provided at least on the first conductive film facing the plurality of insulating protrusions. It is something.

[0013]

[Operation] In the present invention, the lubricating layer reduces the friction with the insulating projections and reduces the force applied to the insulating projections.

[0014]

[Embodiment] Figures 1 to 5 show an embodiment of the present invention. In the figures, 21 is a transparent first insulating sheet that can be easily displaced in the thickness direction by stress, and is made of glass, polyethylene, etc. It is made from terephthalate, polyethylene naphthalate, polybutylene terephthalate, polycarbonate, polyether sulfone, polysulfone, epoxy, acrylic, etc. 22 is a first conductive film which becomes a movable electrode consisting of a transparent conductive film formed with a uniform thickness over the entire surface of the first insulating sheet, and includes gold, nickel, palladium, chromium, tin oxide,
Made of indium oxide, tin, copper iodide, etc., the surface resistance of the base material is 10 to 104Ω/□, and the visible light transmittance is 30
% or more.

Reference numeral 23 denotes a conductive lubricant layer having a lower coefficient of friction than the first conductive film 22 formed on the entire surface of the first conductive film, such as a surfactant, a lubricant, a silicone emulsion, etc. It is a thin film with a thickness of 1 μm or less. Reference numeral 24 denotes a first movable side lead which is one signal extraction electrode electrically connected to the first conductive film 22, which is formed on one side end of the first conductive film 22, and is made of gold. ,
Silver, silver/carbon, carbon, aluminum, copper, silver/
It is made of a conductive material such as copper, nickel, tin, or solder, and the resistance value of the base material is 10 times or more smaller than the resistance value of the first conductive film 22.

Reference numeral 25 denotes a second movable side lead which is the other signal extraction electrode electrically connected to the conductive film 22, and is formed on the other side end of the first conductive film 22, and is connected to the first conductive film 22. It is made of the same conductive material as the movable side lead 24 of. 26 is a movable electrode sheet constituted by the first insulating sheet 21, the first conductive film 22, the lubricating layer 23, and the first and second movable leads 24 and 25.

27 is a second insulating sheet disposed opposite to the first insulating sheet 21; 28 is a second insulating sheet having a uniform thickness over the entire surface of the second insulating sheet facing the first conductive film 22; The second conductive film is a fixed electrode formed of a transparent conductive film, and is made of the same conductive material as the first conductive film 22 described above. Reference numeral 29 denotes a first fixed side lead which is one signal extraction electrode electrically connected to the second conductive film 28.
The movable lead 24 is formed on one side end of the movable lead 24, is made of the same conductive material as the first movable lead 24, and is disposed perpendicular to the first and second movable leads 24 and 25. 30
is a second fixed side lead which is the other signal extraction electrode electrically connected to the second conductive film 28, and is formed on the other end of the second conductive film 28, and is connected to the first It is made of the same conductive material as the movable lead 24 and is arranged perpendicular to the first and second movable leads 3 and 4.

31 is formed on the second conductive film 28 in the lateral direction (
Between the first conductive film 22 and the second conductive film 2, micro insulating protrusions are made up of a plurality of microdot spacers provided in a matrix at regular intervals in the X direction) and the vertical direction (Y direction). A photoresist material is applied to the entire surface of the second conductive film 28, and this photoresist material is exposed to light. It is formed by a microdot spacer method in which a plurality of insulating protrusions 11 are formed by developing and cleaning, leaving only the necessary portions. 32 is the second insulating sheet 27, the second conductive film 28,
This is a fixed-side electrode sheet composed of first and second fixed-side leads 29 and 30 and a plurality of minute insulating protrusions 31.

Next, a method of using the flat switch constructed in this manner will be explained. First, when turning on the switch, press the first insulating sheet 21 with your finger or a writing instrument P such as a ballpoint pen.
At the same time, the first conductive film 22 and the lubricant layer 23 move downward, and the first conductive film 22 comes into contact with the second conductive film 28 via the lubricant layer 23, and finally the first and second movable A stable electrical current is established between the side leads 24 and 25 and the first and second fixed side leads 29 and 30 via the first conductive film 22 and the second conductive film 28. The resistance value in this stable current-carrying state is the resistance value of the first and second conductive films 22, 28, the lubricating layer 23,
First and second movable leads 24, 25, first and second
Although it goes without saying that it varies depending on the fixed side leads 29 and 30, it is usually 2 to 3 kΩ or less. Note that the conductive state is defined by detecting the stable resistance between the first conductive film 22 and the second conductive film 28.

At this time, the insulating protrusions 11 made of microdot spacers come into contact with the lubricant layer 23 and slide, but since the coefficient of friction of the lubricant layer 23 is small, the stress applied to the insulating protrusions 11 is small and it does not peel off. There is no such thing.

When the switch is released, the pressing force by the writing instrument P is removed, that is, when the external stress applied to the first insulating sheet 21 is reduced, the elastic force of the first insulating sheet 21 itself returns to its original state. The contact resistance between the lubricant layer 23 and the second conductive film 28 increases, and eventually the lubricant layer 23 and the second conductive film 28 become non-conductive, and the first The insulating sheet 21, the lubricating layer 23, and the first conductive film 22 return to their original states.

In this way, by applying or removing external stress to the first insulating sheet 21, the first electrically conductive film 22 and the second electrically conductive film 28 are brought into a conductive state via the lubricating layer 23. The switch state can be determined by detecting this state using an external circuit. That is, as described in the conventional example above, the first and second movable leads 24 and 25 are connected to the constant current source S or the constant voltage source, and the first and second fixed leads 29 are connected to the constant current source S or the constant voltage source.
, 30 are grounded, and the first and second movable leads 24, 2
By detecting the current ratio (X coordinate) flowing into the terminal 5 and the current ratio (Y coordinate) flowing out from the first and second fixed side leads 29 and 30, the coordinate (X coordinate) of the position pressed by the writing instrument P is determined. , Y) can be obtained by the above formulas (1) to (3).

In the microswitch configured as described above, the minute insulating protrusions 31 are microdot spacers formed by the microdot spacer method, so the dead zone area in the minute insulating protrusions 31 and the vicinity thereof is shown in FIG. It can be made sufficiently smaller than the conventional one shown in 6, and can sufficiently support high resolution of 4 to 5 pieces per 1 mm, and the minute insulating protrusions 31 contact and slide on the lubricating layer 23 with a small coefficient of friction. There is no peeling.

[0024] In the above embodiment, the first and second
The conductive films 22 and 28 of the first and first insulating sheets 21,
Although the analog type flat switch is shown as having a uniform thickness formed over the entire surface of the conductive film 27, the first and second conductive films 22 and 28 are formed on the first and first insulating sheets 21.
, 27 may be applied to a flat switch of the digital type (the input part is digital and the detection part is analog) formed in a pattern on the surface of 27, or it can be applied to the flat switch of the combination of the analog method and the digital method. It's a good thing.

Furthermore, in the above embodiment, the lubricating layer 23
is formed on the first conductive film 22 which becomes a movable electrode, and the minute insulating projections 31 are formed on the second conductive film 28 which becomes a fixed electrode. To,
The minute insulating protrusions 31 may be formed on the first conductive film 28.

[0026]

Effects of the Invention As described above, the present invention provides a plurality of minute insulating projections on the second conductive film formed on the surface of the second insulating sheet, and Since a lubricating layer is provided on the first conductive film formed on the surface of the insulating sheet, the minute insulating protrusions and the dead zone area in their vicinity can be made sufficiently small, high resolution can be obtained, and the minute insulating protrusions can be This has the effect of suppressing peeling.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

[Fig. 2] Movable electrode sheet 2 in the embodiment shown in Fig. 1
FIG.

FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1;

[Fig. 4] Fixed electrode sheet 3 in the embodiment shown in Fig. 1
FIG.

FIG. 5 is a cross-sectional view taken along line V-V and a partially enlarged cross-sectional view of FIG. 4;

FIG. 6 is a configuration diagram showing a conventional transparent flat switch.

[Fig. 7] Movable electrode sheet 5 in the conventional example shown in Fig. 6
A plan view showing.

FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7;

[Fig. 9] Fixed electrode sheet 1 in the conventional example shown in Fig. 6
A plan view showing 0.

FIG. 10 is a sectional view taken along line XX in FIG. 9;

FIG. 11 is a diagram for explaining the operation of a flat switch.

FIG. 12 is a diagram for explaining the detection status of a flat switch.

[Explanation of symbols]

21 First insulation sheet 22 First conductive film 23 Lubricant layer 27 Second insulation sheet 28 Second conductive film 31. Micro insulating protrusions

Claims (1)

[Claims] 1. A first insulating sheet, a second insulating sheet disposed opposite to the first insulating sheet, and a first insulating sheet formed on a surface of the first insulating sheet opposite to the second insulating sheet. a second conductive film formed on the opposite surface of the first insulating sheet in the second insulating sheet;
a plurality of insulating protrusions distributed on the second conductive film;
A flat switch comprising a lubricant layer having a coefficient of friction smaller than that of the first conductive film on the first conductive film facing at least the plurality of insulating protrusions.