JPS641885B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a keyboard for an electronic desktop calculator, and in particular does not require individually molded resin push buttons 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, it is not possible to reduce the thickness of the electronic desktop calculator body, 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, so that it can be used on the keyboard of an electronic desktop computer. A mirror-image symmetrical pattern consisting of predetermined display numbers, symbols and characters such as four arithmetic calculation keys, memory keys, function command keys, etc. is screen or gravure printed to a thickness of 2 to 10 μm, and the formed printing surface is dried. In this way, the numbers, symbols, characters, etc. of the predetermined display can be accurately seen through the surface of the insulating substrate due to the opaque coloring.

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 on which the mirror image pattern is printed on the back side at a temperature of 50 to 150°C, (a) graphite powder with a particle size of 0.1 to 60μ, silver powder with a particle size
20 to 80% by weight of conductive fine powder consisting of one or more types of carbon black powder of 0.1μ or less, and (b) one or more types of chloroprene rubber, chlorosulfonated rubber, polyurethane resin, and polyester resin. A rubber or thermoplastic resin binder 5 consisting of
~30% by weight and (c) a solvent of dimethylformamide, dimethylacetamide, isophorone, diethyl carbitol, butyl carbitol or turpentine oil.
15 to 80% by weight (A+B+C) was dissolved and uniformly dispersed with an apparent specific gravity of 0.9 to 1.9 and a viscosity of 150.
Using a suspension paint of ~1200 poise, screen or gravure print to a thickness of 25 to 50μ on each printed element such as numbers, symbols, letters, etc. of the mirror image pattern, and heat the printed surface to a temperature of 10~ at 80~150℃
Heat and dry for 30 minutes to form an insulating substrate film on the surface of the keyboard, 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, its It is unnecessary in terms of strength and durability, and is preferable.
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 may be affected by the so-called "glue", that is, the adhesion or adhesion of the paint that becomes the ink. Consistency, that is, viscosity, or viscosity, that is, viscosity, that is, both become unfavorable, and especially below the lower limit, the conductivity of the film becomes extremely poor and it no longer has properties as an electrical conductor.
If it exceeds the upper limit, the adhesive strength will deteriorate and it is not possible.

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 exceeding 0.1μ are not normally available, and in the case of carbon black, the particle size is 0.1μ or less because the graphite and silver powders mentioned above are used. Unlike,
This is because 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, chloroprene rubber such as Neoprene WRT WD (trademark) manufactured by Showa Neoprene Co., Ltd., and chlorosulfonated rubber such as Hypalon No. 30.40 (trademark) manufactured by Dupont Co., Ltd., 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 binder is limited, i.e., less than the lower limit of 5 to 30% by weight, the dispersion stability of the suspension and the "glue" of printing may be affected.
It is not good, the consistency is not good, and the printability is not good.
Not possible. Exceeding the upper limit is not acceptable because the consistency is too high, which worsens printability and significantly deteriorates conductivity.

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 to do. If the upper limit is exceeded, the suspension will be too diluted and the "glue" will be poor and printing will be difficult. This is not allowed as it will result in poor sex.

For the preparation of the suspension described above, the composition raw materials (a)
(B) and (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 a 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 compromised.
Moreover, the adhesion strength deteriorates and cannot be used.

In this case, "apparent specific gravity" is the "apparent density" expressed in specific gravity, and refers to this type of suspension in which insoluble porous solid particles are dispersed and suspended in an organic solvent. It is a measurement scale that serves as a guideline for on-site quality control of turbid liquids, and is generally used in the industry 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 deteriorated, which is unacceptable.

Next, the application thickness of this suspension paint was limited to 25 to 50μ, in order to conduct or cut off the electrical bridge between the contact points that send signals. This is not possible because there is a risk that the signal will not be sent reliably due to insufficient contact at the time. 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.

After completing the step (A) as described above, 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 sheet, polyethylene sheet,
polypropylene sheet, polyvinyl chloride sheet,
Ethylene-vinyl acetate copolymer sheets, papers,
Use nonwoven fabric, etc. 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 other hand, it will not work unless you press it downward very strongly, so it is not possible. 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. The three parts placed on the printed circuit board are fixed 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 the numbers, symbols, etc. displayed when viewed from the surface of this keyboard will be similar to the color of the opaque colored insulating paint mentioned above if a colorless and transparent one is used for the insulating substrate film on the surface. , the color of the surrounding background is close to that of the above-mentioned suspension paint (which itself usually exhibits black, grayish-black, gray, grayish-white, etc.). Therefore, considering the color tone of the background, it is better to select and use bright colors such as red, orange, and yellow for the opaque colored insulating paint, as this will provide better contrast and sharpness. It is easy to see from the surface.

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. Further, it is possible to eliminate the process of assembling a large number of individual buttons, which is currently performed when assembling an electronic desktop calculator, 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
Using Nazda Corporation (trademark) N-170 as a colored insulating paint on the back side of the (see figure), the numbers required for the electronic desk calculator keyboard and the symbols of the four arithmetic calculation keys, memory keys, function command keys, or A mirror-symmetric pattern 3 consisting of letters 2 was screen printed to a thickness of 5 μm, and the printed surface was dried at a temperature of 120°C. In this way, the colored insulating coating layer 4 of the mirror image pattern 3 was formed (see Figures 2a and 2b).

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
B+C) were printed in a circular pattern covering the insulating coating layer 4 of the mirror image pattern 3 to a thickness of 30 μm by screen printing, and dried at a temperature of 100°C. In this way, a conductive layer area 5 is further formed by the suspension paint, covering the surface and surrounding area of the colored insulating coating layer 4 (this portion can be seen through the surface of the substrate film 1 as each colored display of the keyboard). be done. This completes the step (A) of manufacturing the surface insulating substrate film 6 of the keyboard (third step).
(see figures a and 3b).

200μ thick polyester intermediate insulation sheet 7
, an opening 8 corresponding to the conductive layer area 5 formed on the back surface of the front insulating substrate film 6 of the keyboard.
An intermediate insulating sheet 9 having an opening was formed (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 keyboard thus obtained had excellent durability and perfect signal transmission and disconnection. 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 when silver powder was used to replace the entire amount and half of the amount of graphite powder in (a) above, substantially the same results were obtained as long as the apparent specific gravity and viscosity were kept within the above-mentioned limited ranges.

Example 2 On the back side of a polyester substrate film 1 with a thickness of 100 μm, NY- manufactured by Nazda Corporation (trademark) was applied as an insulating coating.
142, numbers, four arithmetic calculation keys, memory keys, etc. required for electronic desktop calculator keyboard.
A mirror-symmetric pattern 3 consisting of symbols or letters 2 of function command keys was screen printed to a thickness of 3 microns, and the printed surface was dried at a temperature of 120°C. In this way, the insulating coating layer 4 of the mirror image pattern 3 was formed.

Next, (a) 20% by weight of graphite powder with a particle size of 0.1 to 60μ and 40% by weight of silver powder with a particle size of 0.1 to 60μ; (b) 20% by weight of polyurethane resin, namely Paraprene 25S (trademark) manufactured by Nippon Polyurethane Co., Ltd.; (c) A suspension paint (a + b + c) consisting of 20% by weight of butyl carbitol was applied to the insulating coating layer 4 of the mirror symmetrical pattern 3.
A circle covering this was printed on top using a screen printing method with a thickness of 30μ, and dried at a temperature of 100℃.
In this way, a conductive layer area 5 is further formed by the suspension paint, covering the surface and surrounding area of the insulating coating layer 4 (this portion can be seen through the surface of the substrate film 1 as each display of the keyboard). be done. This completes the step (A) of manufacturing the surface insulating substrate film 6 of the keyboard.

An intermediate insulating sheet 7 made of polyamide with a thickness of 150μ,
Openings 8 corresponding to the conductive layer areas 5 formed on the back surface of the front surface insulating substrate film 6 of the keyboard were formed to form an intermediate insulating sheet 9 provided with the openings 8 (Step B).

Next, the surface insulating substrate film 6 of the keyboard is stacked in correspondence with the intermediate insulating sheet 9, and placed on the printed circuit board 11 for an electronic desktop calculator on which each corresponding predetermined contact portion 10 is formed. The components 6, 9, and 11 are fixed together, and step C ends.
The keyboard thus obtained had excellent durability, and signal transmission and disconnection were perfect. Also, since there are no buttons, etc., the product is extremely thin.Also, almost the same results can be obtained by using chloroprene rubber, chlorosulfonated rubber, polyester resin, etc. in place of the polyurethane resin (b). Ta.

Furthermore, even if carbon black powder is used to replace all or half of the amount of silver 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. It was done.

Example 3 Using solder resist S-20 manufactured by Taiyo Ink Manufacturing Co., Ltd. (trademark) as an insulating coating on the back side of a polyester substrate film 1 with a thickness of 80μ, numbers and four arithmetic calculations required for an electronic desk calculator keyboard were prepared. A mirror image pattern 3 consisting of keys, memory keys, function command key symbols, or characters 2 was screen printed to a thickness of 5 μm, and the printed surface was dried at a temperature of 150°C. In this way, the insulating coating layer 4 of the mirror image pattern 3 was formed. Next, (a) particle size 0.1
35% by weight of graphite powder of ~60μ and 10% by weight of carbon black with a particle size of 0.1μ or less, (b) 25% by weight of chloroprene rubber, neoprene WRT manufactured by Showa Neoprene Co., Ltd. (trademark), and (c) 30% by weight of isophorone.
A suspension paint (a+ro+c) consisting of the above was printed on the insulating coating layer 4 of the mirror-image symmetrical pattern 3 in a circular shape with a thickness of 25 μm by screen printing method, and the temperature was 100°C. It was dried. In this way, a conductive layer area 5 made of the suspension paint is further formed covering the surface and surrounding area of the no-coat layer 4 (this portion can be seen through the surface of the substrate film 1 as each display on the keyboard). be done. This completes the step (A) of manufacturing the surface insulating substrate film 6 of the keyboard.

100μ thick polyethylene intermediate insulation sheet 7
, an opening 8 corresponding to the conductive layer area 5 formed on the back surface of the front insulating substrate film 6 of the keyboard.
was formed to form an intermediate insulating sheet 9 having openings 8 (Step B).

Next, the surface insulating substrate film 6 of the keyboard is stacked in correspondence with the intermediate insulating sheet 9, and placed on the printed circuit board 11 for an electronic desktop calculator on which each corresponding predetermined contact portion 10 is formed. The components 6, 9, and 11 are fixed together, and step C ends.
The keyboard thus obtained 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 when polyurethane resin, chlorosulfonated rubber, polyester resin, etc. were used in place of the chloroprene rubber (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. .

[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. Figure 2b is a perspective view of the symmetrical pattern, Figure 2b is a schematic cross-sectional view thereof, Figure 3a is a perspective view of the back side of the front insulating substrate film of the keyboard, Figure 3b is a schematic cross-sectional view thereof, and Figure 4 is a schematic cross-sectional view of the symmetrical pattern. FIG. 5 is a perspective view of an insulating sheet, FIG. 5 is a schematic perspective view of a printed circuit board for an electronic desk calculator, and FIG. 6 is a schematic cross-sectional view showing a keyboard for an electronic desk calculator according to an embodiment of the present invention. 1...Substrate film, 2...Numbers required for the electronic desk calculator keyboard, and symbols or characters such as the four arithmetic calculation keys, memory keys, function command keys, etc., 3...Mirror-image symmetrical pattern of 2, 4... ...Insulating coating layer with mirror image symmetry 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 part (of circuit board), 11...Printed circuit board for electronic desk calculator, 12...Liquid crystal Display tube, 13...copper circuit.

Claims (1)

[Claims] 1. On the back side of a transparent flexible insulating substrate film, an opaque colored insulating paint is used to form a mirror-symmetrical pattern consisting of numbers, symbols, and characters to be displayed in a predetermined manner on a keyboard for an electronic desktop calculator. Screen or gravure printing is performed to a thickness of 2 to 10μ, and after drying the formed print surface, (a) one or more of graphite powder with a particle size of 0.1 to 60μ, silver powder, and carbon black powder with a particle size of 0.1μ or less Consisting of 20-80% by weight of conductive fine powder
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, further screen to a thickness of 25 to 50 μm into circular, oval, and polygonal shapes surrounding each printed element of numbers, symbols, and letters in the mirror image pattern. or gravure printing and drying to form a keyboard surface insulating substrate film each provided with a conductive layer area.
(A); (B) forming a flexible intermediate insulating sheet having openings corresponding to the conductive layer areas of the insulating substrate film; A step (C) of placing the substrate on a printed circuit board for an electronic desktop calculator on which corresponding predetermined contact portions are formed in the area via the corresponding intermediate insulating sheet, and fixing the three parts together. By pressing or releasing a predetermined mark that can be seen through the surface of the surface insulating substrate film through the opening of the intermediate insulating sheet, electrical bridge conduction or interruption between the contact portions of the printed circuit board is established. A method of manufacturing a keyboard for an electronic desk calculator, characterized by: 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 desk calculator according to any one of claims 1 to 2.