JPS62116229A - Key hitting force sensor - Google Patents

Abstract

PURPOSE:To reduce the irregularity of load and output voltage characteristics and to make the reproducibility thereof excellent, by forming an electric circuit to a first electric insulating substrate and covering the same with a carbon electrode. CONSTITUTION:Two parallel electrodes 2 are provided to a polyester film 1 by a polyurethane resin and, further, electrodes 3 are provided by coating the electrode 2 with a carbon compounded polyurethane resin to form an electric circuit A to the first substrate film. Next, one electrode 12 corresponding to two electrodes 3 are provided to a polyester film 11 having the same size as the first substrate film and also covered with the carbon compounded polyurethane resin to provide an electrode 13 and, by this method, an electric circuit B is formed to the second substrate film. Further, a pressure-sensitive conductive layer 4 made of pressure-sensitive conductive silicone rubber is provided on the electric circuit B of the second substrate film. The electric circuit film B having the conductive layer 4 and the electric circuit film A are laminated by a pressure-sensitive adhesive 5 so as to allow the electrodes 2, 3 to correspond to the electrodes 12, 13.

Description

Detailed Description of the Invention [Technical Field of the Invention 1] The present invention relates to a keying force sensor, and in particular, the present invention relates to a keying force sensor, which has a novel structure, has small variations in load Φ and output voltage characteristics, has excellent reproducibility, and is thin. The present invention relates to a keying force sensor that can be integrated and integrated and is highly mass-producible.

[Technical Background of the Invention] Various switches using the pressure-sensitive conductive layer rubber sheet 1- as an input element are frequently used in electronic components. An example of an input switch using a pressure-sensitive conductive rubber sheet is the general 0N-O
In addition to the FF switch, input elements for handwriting input position detection devices are also known.

Furthermore, by applying the pressure-sensitive sensor properties of pressure-sensitive conductive rubber, we developed a pressure-sensitive conductive N-type rubber sheet (Japanese Patent Laid-Open No. 53-7993
A key-pressing force sensor for electronic organs has been put into practical use.
This has a structure in which a ribbon of pressure-sensitive conductive rubber sheet 1 - sandwiched between metal sheets for electrodes is placed in a shallow groove provided in an extruded polyvinyl chloride resin material, and the ribbon is covered with felt from above. After pressing the keyboard to produce a sound, by applying more pressure to the keyboard, the resistance change of the sensor is as small as 1! ,
This is converted into a terminal-to-terminal signal using a constant current, and output as a specified control signal using an operational amplifier to control the volume, tone, or pitch.

However, the method using this pressure-sensitive conductive rubber seal 1-
Since the load and output voltage characteristics vary and the reproducibility is poor, it is only used as a keying force sensor with very low accuracy. Furthermore, when manufacturing this keying force sensor, a very long ribbon-shaped seam is required, and current molding methods are not suitable for mass production, are difficult to connect with electrodes, and are expensive. have.

[Object of the invention] The present invention has been made to eliminate the above-mentioned drawbacks. It has a novel structure, has small variations in load and output voltage characteristics, has excellent reproducibility, is thin, The present invention aims to provide a keying force sensor that can be integrated and is highly mass-producible.

[Structure of the Invention] According to the present invention, an electric circuit configured on a first electrically insulating substrate and covered with a carbon electrode;
an electric circuit formed on a second electrically insulating substrate and covered with a carbon electrode, and placed at a distance from the electric circuit on the first substrate; The keying force sensor υ- is characterized by comprising a pressure-sensitive conductive layer adhered to at least one of the substrates and disposed in the gap.

The electrically insulating substrate used in the present invention may be either plate-like or film-like, and may be either rigid or flexible. Examples include films, laminates, and molded products made of phenol resin, epoxy resin, polyester resin, silicone resin, polyimide resin, natural or synthetic rubber, and the like. And its thickness is 0,015iIa~2
A range of Ill is suitable, particularly preferably from 0.1 to
It is in the range of 0.511III. 0.1511II
If it is less than 11, screen printing will be difficult and the strength will be weak;
If it exceeds I1 gl, moldability is poor (cost increases).

In addition, the electric circuit formed on the above board can be formed by attaching a conductive metal foil to the board and then etching it, by vapor depositing a conductive metal, or by using a conductive paste such as silver.
The screen printing method is suitable for forming long ribbon-like patterns accurately and economically.

Furthermore, screen printing of Rikibon paste is also suitable for coating the carbon electrode on the electric circuit.

The pressure-sensitive conductive layer that is then deposited on the circuit is suitably a silicone rubber with dispersed particles of one or more metals such as silver, copper, nickel, and carbon black. In particular, as a metal powder, JP-A-59-981
It is preferable to use a metal powder such as the nickel powder used in Publication No. 64 that has been surface-treated with a platinum compound because the variation in load and output voltage characteristics is small and the reproducibility thereof is excellent. In addition, this composition can also have good adhesion to the substrate and can be applied directly to the electrode by methods such as screen printing.
The extremely long ribbon-like shape, which was a disadvantage of the conventional method, can be easily formed and integrated.

The thickness of the pressure-sensitive conductive layer is suitably 10 μm or more and less than 80 μm from the viewpoint of pressure-sensitive conductivity, preferably 25 μl to 50 μm.
It is μl. If it is less than 10 μm, it will be difficult to obtain initial insulation, and if it is 80 μm or more, the output voltage will be too low and its variation will be large.

In addition, the first and second electrically insulating substrates are bonded together with an electrical circuit and a pressure-sensitive conductive layer placed in the middle, and a mounting board is mounted on the electric T-A11. It is preferable that it be easily cured. The bonding method may be any method such as forming a Jζ adhesive on screen printing and bonding, bonding with double-sided adhesive tape, bonding with various other adhesives, etc.
From the point of view of economy +4, a method of forming an adhesive by screen printing and bonding is suitable.

Furthermore, felt may be attached to the keypad 1 to make it integrated, or double-sided adhesive tape may be attached to the lower part of the keypad to make it easier to set it on the mounting board of an electronic organ.

By combining the components according to the present invention as described above, a keying force sensor for an electronic organ is provided.

[Examples of the Invention] The present invention will be described in detail with examples below, but the present invention is not limited to the examples only, provided that the gist of the invention is not impaired. In the reference example, the part [first all represent the it part].

Reference Example 1 (Manufacture of conductive metal powder treated with platinum compound) To 100 parts of nickel particles with an average particle diameter of 3 to 7 μm obtained from nickel carbonyl, 100 parts of a 1% by weight xylene solution of a vinylsiloxy4non-coordinated platinum complex was added. , which was stirred and heated to reflux.

After 4 hours, the complex-treated powder was filtered and washed, and
The platinum-siloxane complex treated nickel particles were heated at 0° C. for 2 hours.

Reference Example 2 (Manufacture of pressure-sensitive conductive silicone rubber paste) Additive silicone rubber [TSE manufactured by Toshiba Silicone Corporation
3221] 300 parts of the platinum-siloxane complex-treated nickel particles of Reference Example 1 and 6 parts of Aledylene Black were premixed with 100 parts using a small blender, and then dispersed using three rolls to form a pressure-sensitive conductive layer silicone rubber. A composition was obtained. Further, to 100 parts of this composition, 1.0 parts of a solvent [Vialom 28 manufactured by Yasugoku Co., Ltd.] was added to adjust the viscosity.
5 parts were added and diluted to obtain a pressure-sensitive conductive silicone rubber paste.

Example 1 As shown in the cross-sectional view of Fig. 1, the size is 20 x 1000
Polyester film 1 with a thickness of 188 μm in mm,
By providing two parallel electrodes 2 made of polyurethane resin containing silver particles, and further covering the electrodes 2 with polyurethane resin containing carbon to provide electrodes 3, an electric circuit is formed on the first substrate film. Formed.

Next, as shown in the cross-sectional view of FIG. One electrode 12 is provided, which is also covered with carbon-containing polyurethane resin in the same way as the electrode 2.
3, an electric circuit was formed on the second substrate film.

Further, on the electric circuit of the second substrate film shown in FIG. 2, a pressure-sensitive conductive layer 4 made of the pressure-sensitive conductive silicone rubber obtained in Reference Example 2 was provided to a thickness of 40 μm.

A cross-sectional view of the structure in which the pressure-sensitive conductive layer 4 is formed is shown in FIG.

Next, as shown in FIG. 4, the electrical circuit film provided with the pressure-sensitive conductive layer shown in FIG. 3 and the electrical circuit film shown in FIG. They were bonded together with adhesive 5 to form a keystroke force sensor 6.

Comparative Example 1 Keystrokes were the same as in Example 1, except that the formation of the pressure-sensitive conductive layer in Example 1 was replaced with assembly using a pressure-sensitive conductive rubber sheet (manufactured by Yokohama Rubber ■) with a thickness of 0.5 II lil. Constructed a power sentry.

[Effects of the Invention] In order to evaluate the keystroke force sensor of the present invention, as shown in FIG.
It was attached and set on the mounting plate 10 under the mounting plate 9 with double-sided adhesive tape 7.

For evaluation, RLC5 was used between the two parallel electrodes 1 and 2 in Figure 1.
V was applied, and the relationship between the load and the output voltage when a cart was applied to the keyboard, and the variation thereof, were measured.

Figure 6 shows the results of 10 measurements with the same load position on the keyboard, and Figure 7 shows #j! The results are shown when the load position of the board was measured 10 times by changing the location every 50 m+. In the graph, the solid line connects the average value, and the dashed line connects the maximum and minimum values.

As can be seen from FIGS. 6 and 7, the keystroke force sensor of the present invention had characteristics with almost no variation and excellent reproducibility.

On the other hand, the same evaluation was made for the keystroke force of Comparative Example 1. Figure 8 shows the results when the load position on the keyboard was measured 10 times at the same location, and Figure 9 shows the result when the load position on the keyboard was measured 10 times at different locations every 50 m1. showed that. As seen from FIGS. 8 and 9, the keystroke force sensor of Comparative Example 1 has a different output voltage value every time it is measured, and it is difficult to obtain the reproducibility.

As explained above, according to the present invention, it has a novel structure, small variations in load and output voltage characteristics, excellent reproducibility, and excellent keying force for mass-produced tl+ that can be made thinner and more integrated. Sen No. - will be provided.

[Brief explanation of drawings]

1 to 4 are diagrams for explaining the present invention in detail, in which FIG. 1 is a schematic cross-sectional view of a first substrate with an electric circuit, FIG. 2 is a schematic cross-sectional view of a second substrate with an electric circuit, Figure 3 is a schematic cross-sectional view of the second substrate with a pressure-sensitive conductive layer provided on the electrical circuit shown in Figure 2, Figure 4 is a cross-sectional diagram of the keystroke force sensor, and Figure 5 is a test method for evaluating the keystroke force sensor. 6 to 9 are graphs explaining the present invention in detail. DESCRIPTION OF SYMBOLS 1... First electrically insulating substrate (polyester film), 11... Second electrically insulating substrate (polyester film), 2, 12... Silver electrode, 3゜13...
・Carbon coated electrode, 4...pressure-sensitive conductive layer, 5...
Adhesive layer, 6... Keystroke force sensor, 7... Double-sided adhesive tape, 8... Felt, 9... Keyboard, 1
0...Sensor mounting board. (■njfJ weight (kg) Fig. 6 (V) $TL (kg) (■n chair) E (kg) Fig. 8 (V)

Claims (1)

[Scope of Claims] 1. An electric circuit configured on a first electrically insulating substrate and covered with a carbon electrode, and an electric circuit configured on a second electrically insulating substrate and covered with a carbon electrode, and an electric circuit disposed with a gap from the electric circuit of the first substrate; and a pressure-sensitive conductive layer adhered to at least one of the first and second substrates and disposed in the gap. A keystroke force sensor characterized by: 2. The keying force according to claim 1, wherein the first and second electrically insulating substrates are flexible insulating substrate films or resin plates each having a thickness of 0.015 mm to 2 mm. sensor. 3. The pressure-sensitive conductive layer is formed of a paste in which surface-treated conductive metal powder and carbon black are dispersed in silicone rubber. Keystroke force sensor. 4. The keying force sensor according to claim 1, wherein the pressure-sensitive conductive layer has a thickness of 10 μm or more and less than 80 μm. 5. The keying force sensor according to claim 1, characterized in that the first and second electrically insulating substrates are bonded together with an electric circuit and a pressure-sensitive conductive layer placed in between, and integrated. .