JPS644289B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a keyboard for an electronic desktop calculator, and in particular does not require individually molded resin pushbuttons unlike conventional products, and has excellent electrical conductivity. The present invention relates to a manufacturing method for obtaining a simple keyboard for an electronic desktop computer that is excellent in durability, thin, and suitable.

More than 90% of the keyboards of conventional electronic desktop calculators are equipped with a large number of individual push buttons, requiring a complicated structure to press and release the buttons with the fingertips and move them up and down. Failure of the top and bottom buttons was common. Furthermore, since a button is required, the thickness of the electronic desktop calculator cannot be made thinner, and the cost is also high.

The present invention was made in order to eliminate the above-mentioned drawbacks, and does not use a large number of individual pushbuttons made of resin molded products, and uses relatively simple processes and materials to create a thin, highly durable electronic pushbutton. The present invention aims to provide a method for manufacturing a keyboard for a desktop computer.

In the present invention, first, an opaque colored insulating paint is applied to the back side of a flexible insulating substrate film, such as a transparent polyester film, polyamide film, or polycarbonate film, with a thickness of 30 to 500 μm. A mirror-symmetric reverse pattern consisting of designated numbers, arithmetic calculation keys, memory keys, function command keys, etc. symbols and characters is cut out on a white background and is 2 to 10μ thick.
screen or gravure printing, and dry the formed printed surface. In this way, the insulating substrate can be seen through the surface of the insulating substrate with predetermined display numbers, symbols, characters, etc., and the surrounding ground is covered with an opaque color.

Next, the opaque colored insulating paint to be applied to the back surface of the insulating substrate film includes, for example, NY-170 (trademark), NY-142 manufactured by Nazda Corporation, Solder Resist S- (trademark) manufactured by Taiyo Ink Manufacturing Co., Ltd.
30, S-20, etc. can be used. After drying and baking the insulating substrate film, which has a reverse pattern of the mirror image pattern printed on its back side at a temperature of 50 to 150°C, (a) graphite powder with a particle size of 0.1 to 60μ, silver powder and a particle size of 0.1μ or less. carbon black powder 1
20 to 80 parts by weight of a conductive fine powder consisting of a species or two or more species, and (b) 1 of chloroprene rubber, chlorosulfonated rubber, polyurethane resin, and polyester resin.
5 to 30% by weight of a rubber or thermoplastic resin binder consisting of one or more species, and (c) 15 to 80% by weight of a solvent of dimethylformamide, dimethylacetamide, isophorone, diethyl carbitol, butyl carbitol or turpentine oil. Mixed with (I + B + C)
Dissolved and uniformly dispersed apparent specific gravity 0.9~
1.9, using a suspension paint with a viscosity of 150 to 1200 poise, remove the mirror-symmetric reverse pattern, that is, the outer frame part other than the part necessary as a pattern, that is, the part of the pattern, on a white background. 25-50
Screen or gravure printing is performed on the keyboard, and the printed surface is heated and dried at a temperature of 80 to 150°C for 10 to 30 minutes to form a keyboard surface insulating substrate film each provided with a conductive layer area.

In this case, the flexible insulating substrate film is
In addition to the above, substrates made of natural or synthetic rubber, polypropylene, polyvinyl chloride, etc. can also be used, but if the thickness is less than 30μ, there will be problems with its strength and durability, and if it exceeds 500μ, Considering its strength and durability, it is unnecessary and preferably
It becomes 30-500μ.

Also, the thickness of the printing using the colored insulating paint mentioned above is
If it is less than 2μ, it will be somewhat unclear when looking through the display from the front side of the substrate film, but if it is less than 10μ
There is no need to exceed. As a practical matter, a thickness of 2 to 10 microns is preferred for this type of printing.

Next, the composition of the suspension paint (I +
B + C), the quantity limitation in the composition of graphite, silver powder and carbon black, i.e.
If the upper and lower limits of 20 to 80% by weight are exceeded, the stability and printability of the suspension paint used for printing, commonly known as ``glue'', the adhesion or adhesion of the paint used as ink, and the ``consistency'' may be affected. In other words, if the viscosity or viscosity, that is, stickiness, are both not suitable, especially if it is less than the lower limit, the conductivity of the film will be extremely poor and it will not have the properties as a conductor, and if it exceeds the upper limit, the adhesive strength will be deteriorated. It is impossible for it to get worse.

Regarding the particle size, in the case of graphite and silver powders, if the particle size exceeds 60μ, the stability of the suspension paint and the so-called "glue" of printing will deteriorate, sufficient adhesion will not be obtained, and the printability will deteriorate. Because of the poor conductivity, it is not possible. Further, if the lower limit is less than 0.1μ, it is usually not commercially available and is unsuitable in terms of the viscosity consistency and printability of the suspension. In the case of carbon black powder, the particle size is 0.1μ or less because particles with a particle size of more than 0.1μ are not normally available. This is because, unlike powder, the particles are bonded together like a chain, so even if the particles are fine, they are suitable for printing.

Next, as the thermoplastic adhesive binder, examples of the chloroprene rubber include Neoprene WRT WD (trademark) manufactured by Showa Neoprene Co., Ltd., and Hypalon No. 30.40 (trademark) manufactured by DuPont Co., Ltd. as the chlorosulfonated rubber. As the polyurethane resin, for example, Paraprene 22S 25S (trademark) manufactured by Nippon Polyurethane Co., Ltd. can be used.
However, if the quantity of this rubber-based or thermoplastic resin-based binder is limited, that is, below the lower limit of 5 to 30% by weight, the dispersion stability of the suspension and the "glue" of printing will be poor and the consistency will be insufficient. , the printability is not good and it is not acceptable. If the upper limit is exceeded, the consistency is too high, which worsens the printability, and the conductivity deteriorates significantly, so it is not acceptable.

Next, limit the quantity of the solvent (c), i.e. 15~
If it is less than the lower limit of 80% by weight, the dissolution and dispersibility of the suspension will be poor, and the consistency will become too high, which is impossible. If the upper limit is exceeded, the suspension will be too diluted and the "glue" will be poor, resulting in poor printing. This is not allowed as it will result in poor sex.

For the preparation of the suspension described above, the above composition raw materials (a) and (b) are used.
(C) are mixed in predetermined amounts (A + B + C), dissolved and dispersed to give an apparent specific gravity of 0.9 to 1.9 and a viscosity of 150 to
Prepare 1200 poise suspension paint. In this case, if the apparent specific gravity of the suspension paint produced is less than 0.9, the conductivity will be poor due to a lack of fine powder components such as graphite, silver, and carbon black, and if it exceeds 1.9, the dispersibility of the liquid will be poor. and stability is impaired.
Moreover, the adhesive strength deteriorates and is not possible.

In addition, "apparent specific gravity" in this case is "apparent density".
It is expressed in terms of specific gravity, and is a measurement scale that serves as a guideline for on-site quality control of this type of suspension in which insoluble porous solid particles are dispersed and suspended in an organic solvent. It is generally used in place of "true specific gravity" for convenience.

Regarding the viscosity, if the viscosity is less than the lower limit of 150 poise, the printability will be poor, and if it exceeds the upper limit of 1200 poise, the dispersibility of the liquid will be poor and the printability will be even worse, making it impossible.

Next, the reason for limiting the coating thickness of this suspension paint, that is, 25 to 50 μm, is to ensure electrical cross-link conduction or interruption between the contact points that send signals, that is, "on-off".
If it is less than 25μ, the contact when pressing numbers or other keys will be insufficient, and the signal may not be sent reliably, so it is not possible. Also, it is not possible because it will not be clear when viewed through from the surface. On the other hand, the reason why the upper limit was set at 50μ is that a thickness greater than this is not necessary to reliably transmit signals.

Step (A) is completed as described above, and in the next step (B), a flexible intermediate insulating sheet having openings corresponding to the respective conductive layer areas of the insulating substrate film is formed. This intermediate insulating sheet has a thickness of 30~
300μ polyester sheet, polyamide sheet,
Polycarbonate, polyethylene sheet, polypropylene sheet, polyvinyl chloride sheet, ethylene-vinyl acetate copolymer sheet, paper, nonwoven fabric, etc. are used. Each predetermined opening can be easily obtained by punching or the like. If the thickness is less than 30 μm, it is not possible because there is a risk that it will not function as an intermediate insulating sheet. That is, even though the surface of the surface insulating substrate film is not pressed, there is a risk that the contacts on the lower printed circuit board may become conductive. If it exceeds 300μ,
On the contrary, it is not possible because it will not operate unless you press it downward very strongly. This limit is actually preferred.

Furthermore, in the next step (C), each of the conductive layer areas on the back surface of the surface insulating substrate film is provided with corresponding predetermined contact portions via the corresponding intermediate insulating sheet. Place it on the printed circuit board and fix the three parts together. Thereby, by pressing or releasing a predetermined visible indication of the surface insulating substrate film through the opening of the intermediate insulating sheet with a finger or the like, electrical bridge conduction or interruption between the contact portions of the printed circuit board; In other words, "on-off" is performed.

The electronic desk calculator keyboard according to the present invention is manufactured through the above steps (A), (B), and (C).

Note that the color of numbers, symbols, etc. displayed when viewed from the surface of this keyboard is determined by the above-mentioned suspension paint (usually, if a colorless and transparent insulating substrate film is used on the surface). The color itself is close to black, gray-black, gray, gray-white, etc.), and the color of the surrounding background is close to the color of the opaque colored insulating paint described above. Therefore, it is better to set the background color to a bright color such as ivory, yellow, or green for better contrast and easier viewing.

In addition, the strength of the pressure to activate the keyboard by pressing it with your fingertips, etc., and the speed at which it returns to its original state, etc., depend on the material and thickness of the flexible insulating substrate film on the front side, and the opaque insulating coating printed on the back side. The selection is determined by the thickness of the conductive suspension paint and the material of the flexible intermediate insulating sheet (a type of cushion material), the size and shape of the holes, etc.

The electronic desk calculator keyboard according to the present invention has excellent durability, flexibility, and perfect signal transmission and disconnection, and is fully guaranteed for practical use. Furthermore, it is possible to eliminate the process of assembling a large number of individual buttons, which is currently performed in the assembly of electronic desk calculators, which is rational. Furthermore, surface irregularities caused by buttons can be eliminated, and an electronic desk calculator that is thinner overall can be manufactured.

Examples will be further described below.

Example 1 Polyester substrate film 1 with a thickness of 50μ (first
(See figure) Use Nazda Corporation (trademark) NY-170 as a colored insulating paint on the back side of the board to mark the numbers required for the electronic desk calculator keyboard, as well as the symbols for the four arithmetic calculation keys, memory keys, function command keys, or A mirror-symmetric reverse pattern consisting of character 2 was cut out on a white background, and the entire surrounding area was screen printed to a thickness of 5μ, and the printed surface was dried at a temperature of 120°C (Figures 2a and 2b). reference).

Next, (a) 30% by weight of graphite powder with a particle size of 0.1 to 60μ and 15% by weight of carbon black with a particle size of 0.1μ or less, and (b)
25% by weight of polyurethane resin, namely Paraprene 22S (trademark) manufactured by Nippon Polyurethane Co., Ltd., and (c)
Suspension paint (I+) consisting of 30% by weight of isophorone
Using (b + c), the inverse pattern 3 of the mirror image object
Numbers, symbols, letters, etc. were printed in a roughly circular shape surrounding each element punched out on a blank white background to a thickness of 30 μm using a screen printing method, and dried at a temperature of 100°C. This forms the surface insulating substrate film 6 of the keyboard provided with the conductive layer area 5 (Step A).
(See Figures 3a and 3b).

An intermediate insulating sheet 7 made of polyamide with a thickness of 250μ,
Openings 8 corresponding to the conductive layer areas 5 formed on the surface of the surface insulating substrate film 6 of the keyboard were formed to form an intermediate insulating sheet 9 provided with the openings (Step B) (see FIG. 4). .

Next, the surface insulating substrate film 6 of the keyboard is overlapped in correspondence with the intermediate insulating sheet 9, and the printed circuit board 11 for an electronic desktop calculator is formed with corresponding predetermined contact portions 10 (see FIG. 5). The three parts 6, 9, and 11 are placed on top and fixed together to complete step C (see Fig. 6). The thus obtained keyboard had excellent durability and signal transmission and disconnection were perfect. Also, since there were no buttons, etc., it was extremely thin. In addition, substantially the same results were obtained by using chloroprene rubber, chlorosulfonated rubber, polyester resin, etc. in place of the polyurethane resin (b).

Furthermore, even if silver powder was used to replace all or half of the amount of graphite powder in (a) above, almost the same results were obtained as long as the apparent specific gravity and viscosity were kept within the limited ranges mentioned above. .

Example 2 Polyester substrate film 1 (first
(See figure) solder resist S manufactured by Taiyo Ink Manufacturing Co., Ltd. (trademark) as the colored insulating paint.
-20 is used to create the numbers, four arithmetic calculation keys, memory keys, and keys required for an electronic desk calculator keyboard.
A mirror-symmetric reverse pattern consisting of symbols such as function command keys or characters 2 was printed on the entire surrounding area by screen printing to a thickness of 5 μm without removing the white background, and this printed surface was dried at a temperature of 150°C. (See Figures 2a and 2b).

Next, (a) 35% by weight of graphite powder with a particle size of 0.1 to 60μ and 10% by weight of carbon black with a particle size of 0.1μ or less, and (b)
Suspension paint (a + b +
C) is the number of the reverse pattern 3 of the mirror image object,
A roughly circular shape surrounding each element cut out on a white background with no symbols, letters, etc. printed to a thickness of 30 μm was printed using a screen printing method and dried at a temperature of 100°C. This forms the surface insulating substrate film 6 of the keyboard provided with the conductive layer area 5 (Step A) (see Figures 3a and 3b).

The surface insulating substrate film 6 of the keyboard is placed on the intermediate insulating sheet 7 of polypropylene having a thickness of 100μ.
An opening 8 corresponding to the conductive layer area 5 formed on the back surface of the substrate was formed to form an intermediate insulating sheet 9 provided with the opening (Step B) (see FIG. 4).

Next, in substantially the same manner as in Example 1, the three members 6, 9, and 11 (see FIGS. 3a, 4, and 5) are fixed together to complete step C (see FIG. 6). The keyboard thus obtained had excellent durability, and signal transmission and disconnection were perfect. Also, since there are no large numbers of individual buttons that stick out, it is extremely thin.

In this case, substantially the same results were obtained even when chlorosulfone rubber, polyurethane resin, or polyester resin was used instead of the (b) chloroprene rubber.

Furthermore, even if silver powder is used to replace all or half of the amount of graphite powder in (a) above, almost the same results can be obtained as long as the apparent specific gravity and viscosity are kept within the limited ranges mentioned above. Ta.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an insulating substrate film according to the present invention, and FIG. 2a is a mirror image of numbers, symbols, or characters required for a keyboard for an electronic desk calculator according to an embodiment of the present invention on the back side of the substrate film. FIG. 2b is a schematic cross-sectional view of the symmetrical reverse pattern; FIG. 3a is a perspective view of the back side of the front insulating substrate film of the keyboard according to one embodiment;
FIG. 3b is a schematic cross-sectional view of the same, FIG. 4 is a perspective view of an intermediate insulating sheet provided with an opening, FIG. 5 is a schematic perspective view of a printed circuit board for an electronic desktop calculator, and FIG. 1 is a schematic cross-sectional view showing a keyboard for an electronic desktop calculator according to an embodiment. 1...Substrate film, 2...Numbers required for electronic desk calculator keyboard, and symbols or characters such as four arithmetic calculation keys, memory keys, function command keys, etc., 3...Reverse pattern of mirror image of 2, 4 ... Insulating coating layer with mirror image pattern 3, 5 ... Conductive layer area, 6 ... Keyboard surface insulating substrate film,
7... Intermediate insulating sheet, 8... Opening, 9... Intermediate insulating sheet with opening, 10... Contact portion (of the circuit board), 11... Printed circuit board for electronic desk calculator, 12... ...Liquid crystal display tube, 13...Copper circuit.

Claims (1)

[Scope of Claims] 1. A mirror-symmetric reverse pattern consisting of predetermined numbers, symbols, and characters displayed on a keyboard for an electronic desktop calculator by using an opaque colored insulating paint on the back side of a transparent flexible insulating substrate film. That is, cut out on a white background, screen or gravure print to a thickness of 2 to 10μ, and after drying the printed surface, (a) particle size
20 to 80% by weight of conductive fine powder consisting of one or more of graphite powder of 0.1 to 60μ, silver powder, and carbon black powder of particle size of 0.1μ or less, and (b) chloroprene rubber, chlorosulfonated rubber, polyurethane. 5 to 30% by weight of a rubber or thermoplastic resin binder consisting of one or more of resins and polyester resins
and (c) dimethylformamide, dimethylacetamide, isophorone, diethyl carbitol, butyl carbitol, or turpentine oil in an amount of 15 to 80% by weight (a + b + c) dissolved and uniformly dispersed. Using a suspension paint with a viscosity of 0.9 to 1.9 and a viscosity of 150 to 1200 poise, create circles, ellipses, and polygonal shapes surrounding each element cut out on the white background where no numbers, symbols, or letters of the mirror-symmetric reverse pattern are printed. Step (A) of screen or gravure printing to a thickness of 25 to 50 μm and drying to form an insulating substrate film on the surface of the keyboard, each having a conductive layer area; and openings corresponding to each of the conductive layer areas of the insulating substrate film. a step (B) of forming a flexible intermediate insulating sheet having a section, and further comprising applying a corresponding predetermined layer to each of the conductive layer areas on the back surface of the surface insulating substrate film through the corresponding intermediate insulating sheet. A step (C) of placing a printed circuit board for an electronic desk calculator on which each contact portion has been formed and fixing the three parts together; A method for manufacturing a keyboard for an electronic desk calculator, characterized in that electrical cross-linking or interruption between the contact portions of the printed circuit board is achieved by pressing or releasing the insulation sheet through an opening. 2 The transparent flexible insulating substrate film has a thickness of 30~
The method for producing a keyboard for an electronic desktop calculator according to claim 1, characterized in that the keyboard is made of a 500μ polyester film, polyamide film, polycarbonate film, polypropylene film, polyvinyl chloride film, or natural or synthetic rubber film. 3. The flexible intermediate insulating sheet is made of a polyester sheet, polyamide sheet, polycarbonate sheet, polyethylene sheet, polypropylene sheet, polyvinyl chloride sheet, ethylene-vinyl acetate copolymer sheet, paper, or nonwoven fabric with a thickness of 30 to 300 μm. A method of manufacturing a keyboard for an electronic desktop calculator according to any one of claims 1 to 2.