JPH04345713A - 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 and increase the packaging density of the switch. 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. A plurality o insulating projections 32 which function as spacers to electrically and physically separate both the conductive films 22, 28 from each other are arranged between the first conductive film 22 and the second conductive film 28. A plurality of conductive small particles having conductivity are dispersedly fixed to the first conductive film 22, and when they are made to be conductive, they are first made to electrically contact with the second conductive film 28.

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. In the figures, 1 is a transparent first insulating sheet that can be easily displaced in the thickness direction due to stress, and 2 is the entire surface of this first insulating sheet. A movable electrode film made of a transparent conductive film formed with a uniform thickness on the movable electrode film; 3 is a first movable side lead which is one signal extraction electrode electrically connected to the movable electrode film; It is formed on one side end of the 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 having a uniform thickness over the entire surface of the second insulating sheet opposite to the first insulating sheet 1; A fixed electrode film consisting of a transparent conductive film formed in It is formed on the side end and 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. It is arranged perpendicularly to the movable leads 3 and 4. 10 is the second insulating sheet 6, the fixed electrode film 7, the first and second fixed leads 8,
9. This is a fixed side electrode sheet composed of 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. For example, silicon,
It is made of an insulating material such as 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 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 the fixed electrode In contact with the membrane 7, the first and second movable leads 3, 4
Electricity is applied between the first and second fixed leads 8 and 9 via the movable electrode film 2 and the fixed electrode film 7.

When the switch is released, the pressing force from the writing instrument P is removed, that is, when the external stress applied to the first insulating sheet 1 is reduced, the first insulating sheet returns to its original state due to its own elastic force. The movable electrode film 2 and the fixed electrode film 7 finally become non-conductive, and the first
The insulating sheet 1 and 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.

The present invention has been made in view of the above-mentioned points, and aims to provide a high-resolution flat switch that can extremely reduce the dead zone E with a simple configuration, increase the mounting density of the switch, and provide a high-resolution flat switch. That is.

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 opposite surface of the insulating sheet, a second conductive film formed on the opposite surface of the first insulating sheet in the second insulating sheet, and a second conductive film dispersively fixed to the first conductive film. A plurality of small conductive particles having a certain conductivity and a plurality of insulating protrusions arranged between the first and second conductive films and having a shape larger than the shape of the small conductive particles are provided.

[0013]

[Operation] In this invention, the conductive small particles serve to narrow the distance between the first conductive film and the second conductive film in the vicinity of the insulating protrusion, thereby reducing the dead zone area in the vicinity of the insulating protrusion. .

[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 of terephthalate, polyethylene naphthalate, polybutylene terephthalate, polycarbonate, polyether sulfone, polysulfone, epoxy, acrylic, etc. 22 is a first conductive film that becomes a movable electrode made 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, and indium oxide. - Made of tin, copper iodide, etc., the surface resistance of the base material is 10 to 104Ω/□, and the visible light transmittance is 30%.
This is the structure described above.

[0015] 23 is a plurality of conductive small particles having conductivity that are dispersed and fixed in this first conductive film, and is constructed by dispersing large-shaped conductive particles in a transparent conductive paint, applying and fixing the same. The first conductive film 22 may be formed simultaneously with the first conductive film 22, or may be formed separately. 2
Reference numeral 4 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
It is made of a conductive material such as carbon, carbon, aluminum, copper, silver/copper, nickel, tin, solder, etc., and the resistance value of the base material is 1 with respect to the resistance value of the first conductive film 22.
It is more than 0 times smaller.

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 small conductive particles 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 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 the second insulating sheet 27, the second conductive film 28,
This is a fixed-side electrode sheet constituted by first and second fixed-side leads 29 and 30.

32 is formed on the first conductive film 22 in the lateral direction (
The first conductive film 2 is formed by a plurality of insulating protrusions provided at regular intervals in a matrix in the X direction) and the vertical direction (Y direction).
2 and the second conductive film 28, it functions as a spacer to electrically and physically separate both electrode films 22, 28, and has a bottom diameter of 100 to 500 μm and a height of this spacer. It has a conical shape that is about 10% of the diameter and higher than the conductive small particles 23, and is formed by screen printing 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, when the first insulating sheet 21 is pressed with a finger or a writing instrument P such as a ballpoint pen, the first conductive film 22 and the conductive small particles 23 move downward together with the first insulating sheet 21. First, the conductive small particles 23 come into contact with the second conductive film 28, and finally the first and second movable leads 24, 25 and the first and second fixed leads 29, 30 are connected to each other. A stable current conduction state is established through the first conductive film 22 and the second conductive film 28. The resistance value in this stable energized state is the first
It goes without saying that it changes depending on the second conductive films 22, 28, the small conductive particles 23, the first and second movable leads 24, 25, and the first and second fixed leads 29, 30. It is usually 2 to 3 kΩ or less.

The above-described stable first conductive film 22 and the second
The conductive state is defined by detecting the resistance between the conductive film 28 and the conductive film 28. In other words, in the above embodiment, the difference in height between the insulating protrusion 32 and the small conductive protrusion 23 becomes the inter-electrode gap between the first conductive film 22 and the second conductive film 28. This inter-electrode gap provides pressure-sensitive characteristics.

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 small conductive protrusions 23 and the second conductive film 28 increases, and finally the contact resistance between the small conductive protrusions 23 and the second conductive film 28 increases.
The first insulating sheet 21, the small conductive projections 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, a state of conduction is established between the first conductive film 22 and the second conductive film 28 via the conductive small protrusions 23. and a non-conducting state, and by detecting this state with an external circuit, the switch state can be determined. That is, as explained 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 and 30 are connected to the constant current source S or the constant voltage source. grounded and the first and second movable leads 24
, 25 (X coordinate), and the current ratio (Y coordinate) flowing out from the first and second fixed side leads 29 and 30.
By detecting , the coordinates (X, Y) of the position pressed by the writing instrument P can be obtained by the above equations (1) to (3).

In the microswitch constructed as described above, since the electrode gap between the first conductive film 22 and the second conductive film 28 is reduced by the conductive small protrusions 23, the above-mentioned Even if the insulating protrusion 32 of the same size as the conventional one is used, the dead zone area in the insulating protrusion 32 and its vicinity can be made sufficiently smaller than that of the conventional one; for example, when the diameter of the insulating protrusion 32 is 100 μm. The diameter of the dead zone region can be made sufficiently smaller than 200 μm,
This can sufficiently support high resolution of 4 to 5 lines per mm.

[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.

Further, in the above embodiment, the small conductive protrusions 23 and the insulating protrusions 32 are connected to the first conductive film 2 serving as a movable electrode.
Although the small conductive projections 2 are formed on the second conductive film 28, they may be formed on the second conductive film 28 which becomes the fixed electrode.
3 may be formed on the first conductive film 22, and the insulating protrusion 32 may be formed on the second conductive film 28, or vice versa.

[0026]

Effects of the Invention As described above, the present invention provides a first electrically conductive film formed on the surface of the first insulating sheet opposite to a second electrically conductive film formed on the surface of the second insulating sheet. To,
Since a plurality of small conductive particles having a shape smaller than the shape of a plurality of insulating protrusions arranged between the first and second conductive films are dispersed and fixed, a dead zone area of the insulating protrusions and their vicinity is sufficiently covered. This has the advantage that it can be made smaller and provide high resolution.

[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. 1 is a cross-sectional view taken along III-III and a partially enlarged cross-sectional view.

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

FIG. 5 is a sectional view taken along line V-V in 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 Conductive small projections 27 Second insulation sheet 28 Second conductive film 32 Insulating protrusion

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 small conductive particles having conductivity dispersed and fixed on the first conductive film. , a flat switch including a plurality of insulating protrusions arranged between the first and second conductive films and having a shape larger than the shape of the conductive small particles.