JPH0347528B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a plane coordinate input tablet for inputting two-dimensional patterns such as characters and images.
In detail, it is a pressure-type plane coordinate input tablet using a resistance sheet, and it is a plane coordinate input tablet that can stably detect the pressure input point with high precision even if pressure input is repeated over a long period of time. related to tablets. Planar coordinate input tablets are classified into resistance sheet type, conductive sheet type, optical scanning type, surface wave propagation time detection type, strain gauge type, etc. according to their operating principles. Among these, the resistance sheet type tablet detects the position coordinates of the input point on the resistance sheet from electrical signals such as the ratio of current and voltage, so it has a simple structure in principle, but it is not practical in practice. It is required that the resistance value of the resistance sheet used be uniform in each part on the sheet, and that the resistance value remains constant even after repeated use. However, conventionally known resistive sheet type tablets generally have a problem in that the resistance value of the resistive sheet increases with repeated use, causing distortion in reproduced images. In addition, the resistance sheet in the conventionally known input tablet is made by applying so-called carbon paste, in which conductive material such as carbon powder is dispersed in thermosetting synthetic resin, on one side of an insulating substrate made of a synthetic resin sheet. The resistive sheet is formed by drying and curing after applying it by screen printing, roller coating, etc., so the uniformity of the dispersion of the conductive particles in the paste and the uniformity of the coating thickness are not sufficient. , the input position coordinates do not exactly match the current or voltage ratio, and there is also the problem that the reproduced image is distorted. The present invention solves the above-mentioned problems and provides a tablet for plane coordinate input that has a constant sheet resistance even after repeated use over a long period of time, and therefore provides stable and accurate reproduced images over a long period of time. A further object of the present invention is to provide a tablet for plane coordinate input that can accurately detect input positions from electrical signals such as voltage or current, and is inexpensive to manufacture. shall be. The tablet for plane coordinate input according to the present invention has a resistor layer on an insulating substrate, and a resistor sheet having strip-shaped electrodes on two opposing edges is connected to the resistor layer through a pressure-sensitive conductive sheet. A tablet for plane coordinate input, in which layers are stacked so as to face each other, and detects the position coordinates of a pressure input point on a resistance sheet by an electrical signal,
The above insulating substrate has a tensile modulus of elasticity of 1×10 ³ to 20×10 ³
Kg/cm ² of polyamide, polyamide copolymer, fluororesin, and acrylic-epoxy resin copolymer. The present invention will be described below based on drawings showing examples. In the tablet for plane coordinate input according to the present invention, the resistance sheet 10 includes an insulating substrate 4 and a resistor layer 9 formed thereon, as shown in FIG.
and a band-shaped electrode 6 provided on two opposing edges of the substrate. In the present invention, the insulating substrate for forming the above-mentioned resistance sheet has a tensile modulus of elasticity of 1×10 ³ to
A relatively flexible and elastic sheet made of a 20×10 ³ Kg/cm ² polymer is used. A sheet having a thickness of 80 to 500 μm, preferably 100 to 400 μm is used. When such a sheet is used as an insulating substrate, it is difficult to permanently deform the resistance sheet even if pressure input points are repeatedly applied to the resistance sheet, and the resistance value of the resistance sheet is suppressed from increasing over time. can be detected with high precision over a long period of time. In particular, in the present invention, polyamides, polyamide polymers, polytrifluoroethylene, polytetrafluoroethylene, fluororesins such as tetrafluoroethylene-hexafluoropropylene copolymers, and acrylic-epoxy resin copolymers having the above properties are used. Among these, sheets made of so-called nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, non-stretched polyamides containing these as main components, or copolymers thereof are preferably used. It is preferable that such a polymer has a tensile modulus within the above-mentioned predetermined range and a yield strength within a range of 200 to 800 kg/cm ² . A preferable example of the polyamide or its copolymer is, for example, "Diamide 7000" (tensile modulus 6 x 10 ³ - 12 x 10 ³ Kg/cm ² , yield point strength 130 -
450Kg/cm ² ) and "Diamid 3000" (both polyamide manufactured by Daicel Corporation). Incidentally, polyester has a tensile modulus of 35×10 ³ to 50×10 ³ Kg/cm ² and a yield point strength of approximately
It is 1200Kg/ ^cm2 . Therefore, as an embodiment of the tablet for plane coordinate input according to the present invention is shown in FIG. Upper resistance sheet 1 having a resistor layer on an insulating substrate 4B such as
3 and 3, these resistor layers face each other with the pressure-sensitive conductive sheet 12 in between, and a band-shaped electrode 6Y provided on the opposite edge of the lower resistance sheet and a similar electrode 6X of the upper resistance sheet. are formed by overlapping each other orthogonally. If necessary, a protective sheet 14 is formed on the pressure input side, that is, on the insulating substrate 4B of the upper resistance sheet. Pressure input is performed on the insulating substrate of the upper resistance sheet or the protection sheet, and the position coordinates of the pressure input points applied on each resistance sheet are detected by electrical signals. In the present invention, the resistance sheet may be a sheet formed by applying and curing a so-called conductive paste, which is made by dispersing conductive powder such as carbon powder or metal powder in a thermosetting resin, on an insulating substrate. However, preferably, as explained below, the resistor sheet includes a main resistor layer made of a metal thin film provided on an insulating substrate, and a protective resistor layer covering the surface of the main resistor layer. It has a double structure. To form a metal thin film as the main resistor layer on an insulating substrate, vacuum evaporation, cathode sputtering, electroless plating, CVD (chemical vapor deposition), etc.
Although it is possible to use any of the conventionally known techniques such as ion plating or ion plating, it is easier to make the sheet resistance value of the metal thin film uniform compared to the method of directly forming the metal thin film on an insulating substrate. Preferably, electroplating is used because it provides strong adhesion to the insulating substrate, and there is no need to expose the insulating substrate to high temperatures when forming the metal thin film. The above-described resistance sheet and a tablet for inputting plane coordinates using the same will be explained below with reference to the drawings. One side of the copper foil 1, which will become a conductive layer, is coated with a masking adhesive sheet 2, and then, as shown in FIG. A main resistor layer 3 made of a metal thin film is formed. As for the thickness of the main resistor layer 3 formed by electroplating, since the copper foil surface is highly smooth, a practical thin film of 200 Å can be obtained at its thinnest thickness. Next, as shown in FIG. 4, the adhesive sheet 2 is peeled off, and a flexible insulating substrate 4 is bonded to the surface of the main resistor layer 3. At the opposite edges of the three-layer laminate thus obtained, a fifth
Attach masking tape 5 as shown in the figure,
Next, when the exposed portion of the copper foil 1 is etched away using a copper etching solution, as shown in FIG.
A resistance sheet is obtained in which electrodes 6, 6 are formed on opposite edges of the main resistor layer 3. As shown in FIG. 7, on the main resistor layer 3,
A protective resistor layer 7 is formed. This protective resistor layer is a resistor with high wear resistance that is formed by applying a paste or ink containing powder made of conductive material such as carbon or metal powder and synthetic resin onto the main resistor layer and curing it. This is the body layer. The sheet resistance value of this protective resistor layer is preferably 10 times or more the sheet resistance value of the main resistor layer. Furthermore, when applying the paste onto the main resistor layer, by screen printing or the like, the protective resistor layer 7 not only completely covers the entire surface of the main resistor layer 3 as shown in FIG. Preferably, the inner edges 8,8 of the electrodes 6,6 are also covered. In such a resistor sheet, the resistance value is a parallel composite value of the resistance values of the main resistor layer 3 and the protective resistor layer 7, but the resistance value of the main resistor layer 3 dominates the composite value. Therefore, as long as the sheet resistance value of the main resistor layer 3 is uniform, even if the sheet resistance value of the protective resistor layer 7 is non-uniform, the effect on the composite value is small. Furthermore, the resistance value due to the protective resistor layer 7 is added in series at the input coordinate point, but the thickness of the protective resistor layer 7 is extremely small, for example, 10 μm, and the area related to conduction is, for example, 1 mm ² compared to the thickness. Since the resistance value is sufficiently large, the increase in resistance value can be practically ignored. Further, in the tablet for plane coordinate input of the present invention, as described above, a protective sheet is laminated on the insulating substrate of the upper resistance sheet as necessary. Such a protective sheet may be a conventionally used polyester sheet, but preferably has a tensile modulus of elasticity of 1×10 ³ to 20×10 ³ Kg/cm, similar to that used as an insulating substrate. Polymers of ² , for example, as described above, polyamides having a tensile modulus in the above range, copolymers thereof, polytrifluoroethylene, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymers, etc. A relatively flexible and elastic sheet made of resin, acrylic-epoxy resin copolymer, etc. and having a thickness of 80 to 500 μm, preferably 100 to 400 μm is used. When such a sheet is used, the insulating substrate is also flexible and has elasticity, and as described above, even if pressure input is repeated, the protective sheet and the insulating substrate are unlikely to undergo permanent deformation. It is possible to suppress the increase in the resistance value of the resistance sheet over time, and therefore to detect the pressure input point with high accuracy. In particular, according to the present invention, as described above, when the main resistor layer is made of a metal thin film and this is covered with a protective resistor layer, the tensile modulus of elasticity of the protective sheet is 5×10 ³ to 15×10 A sheet or film made of the above-mentioned polyamide, polyamide copolymer, fluorine resin, acrylic-epoxy resin copolymer, etc. with a weight of ³ Kg/cm ² is used, and an insulating film is used in which a metal thin film, which is the main resistor layer, is formed. The substrate is made of polyamide, polyamide copolymer, fluororesin, acrylic-epoxy resin copolymer, etc. and has a thickness of about 30 to 300 μm and has a tensile modulus and yield point strength of about 50% or less compared to the protective sheet. A sheet or film is used. Therefore, for example, when the above-mentioned "Diamid 7000" is used as the protective sheet, "Diaamide 3000" is preferably used as the insulating substrate. Here, "Diamide 7000" film or sheet has a Young's modulus (100%) of 8000 Kg/cm ² and a yield point strength of 450.
Kg/cm ² , whereas “Diamid 3000” film or sheet has a Young’s modulus (100%) of 1700 Kg/cm2.
cm ² , and the yield point strength is 150 Kg/cm ² . In addition, a sheet or film made of polytrifluoroethylene or polytetrafluoroethylene, which has almost the same physical properties as "Diaamide 7000", is used as the protective sheet, and a sheet or film made of polytrifluoroethylene or polytetrafluoroethylene, which has almost the same physical properties as "Diaamide 3000", is used as the insulating substrate. Hexafluoropropylene copolymers and acrylic-epoxy resin copolymers can also be used. According to the tablet for plane coordinate input of the present invention,
As described above, as the insulating substrate constituting the resistance sheet, polyamide, its copolymer, polytrifluoroethylene,
A sheet made of polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, acrylic-epoxy resin copolymer, etc. is used, and since such a polymer sheet is flexible and has appropriate elasticity, However, unlike insulating substrates made of polyester that have been commonly used in the past, there is virtually no permanent deformation or wear of the sheet due to pressure input, and the resistance value of the resistance sheet remains at a high level over time. It remains constant. Therefore, according to the tablet for plane coordinate input according to the present invention, pressure input points can be detected stably and with high precision over a long period of time. In addition to the above, in the preferred planar coordinate input tablet of the present invention, since the main resistor layer is composed of a metal thin film with a uniform sheet resistance value, a high quality image signal can be obtained. When the metal thin film is formed by electroplating, the copper foil surface is a highly precise smooth surface, and an image signal of even higher quality can be obtained.
Here also, according to the present invention, the main resistor layer has a thickness of
Even if it is a thin film of about 200 Å, its surface is covered with a protective resistor layer, and as mentioned above,
Since a sheet made of the above-mentioned predetermined polymer is used as the insulating substrate, the pressure input point can be detected stably and with high precision over a long period of time. Example 1 As an insulating substrate, a polyamide film "Diamid 7000" and a low melting point polyamide film "Diamid 3000" having a length and width of 30 cm and a thickness shown in Table 1 were used.
Carbon paste (MCP-7002 manufactured by Mitsui Toatsu Co., Ltd.) was applied on top using a roll coater to a thickness of approximately 10 μm, and heated and hardened at a temperature of 110°C for 1 hour.Furthermore, a counter electrode was formed with silver paste. A sheet with an average sheet resistance of 510Ω/□ and a variation of ±10% in each part was manufactured. Similarly, as an insulating substrate,
A resistive sheet was obtained using a polyester film with a thickness shown in Table 1, and a counter electrode was formed using silver paste.The resistive sheet had an average sheet resistance of 490Ω/□, and a variation of ±10% in each part. I got it. In this way, two resistance sheets using polyamide or polyester as insulating substrates were connected to each other through a pressure-sensitive conductive sheet (JSR PCR 505-05 manufactured by Japan Synthetic Rubber Co., Ltd.) with a thickness of 0.5 mm. The body layers are laminated so as to face the body, and further, without laminating a protective sheet on the insulating substrate of the upper resistance sheet, or as shown in Table 1, a polyester film or "Diamide 7000" film is laminated, If there is no protection sheet, apply a normal load of 500g on the insulating substrate of the upper resistance sheet, or from above the protection sheet if it has a protection sheet, on a constant line parallel to the opposing electrode of the upper resistance sheet. Writing was performed 1000 times using a commercially available pole pen, and the change in resistance value between the electrodes of the upper resistance sheet and the sensitivity of writing pressure were measured, and the deformation of the protective sheet and insulating substrate was observed. The results are shown in Table 1. For the change in resistance value, the resistance value before the load test is R ₀ ,
When the resistance value after the test is R, it is given by (R-R ₀ )/R ₀ ×100 (%), and the pen pressure sensitivity is the load required to conduct current between the upper and lower resistance sheets ( (pen pressure). It is clear that in the tablet for inputting plane coordinates according to the present invention, there is substantially no permanent deformation or wear on the protective sheet, and the resistance value of the resistance sheet is constant. Example 2 One side of a copper foil with a thickness of 35 μm and an area of 35 cm x 35 cm was covered with a masking adhesive sheet, and a degreasing liquid and 20%
After dipping in hydrochloric acid and washing with water, the other side of the copper foil is electroplated to a thickness of approximately 500 mm as the main resistor layer.
A thin film of a tin-nickel alloy (approximately 70% tin by weight, remainder nickel) was formed. For this three-layer structure, the adhesive sheet was peeled off from the copper foil, and films made of various polymers were thermocompressed as an insulating substrate on the surface on which the tin-nickel alloy thin film was formed, as shown in Table 2. Next, cut and remove 2.5cm from each of the four sides, and then
A 30 cm square sheet was obtained. Thereafter, masking tape was applied to the 10 mm wide portions of the two opposing sides, and the exposed copper was etched away using an ammonia-based copper etching solution, washed with water, and then dried. Next, the masking tape at both ends was peeled off to obtain a resistance sheet with 10 mm wide copper electrodes at both ends. The average sheet resistance value of this resistance sheet was 500Ω/□, and the variation in each part was within ±3%. A carbon paste (same as above) having a resistance value of 10 kΩ/□ was screen printed on the surface of this resistor layer using a 200 mesh polytetrafluoroethylene screen, and then cured. After curing, the sheet resistance was measured using a four-probe resistance measuring device, and the average was 480Ω/□, with a variation of ±5% for each part.
It was within Two resistance sheets obtained in this way were used in Example 1.
In the same manner as above, the resistor layers are laminated so as to face each other with the conductive sheet interposed therebetween, and without laminating a protective sheet on the insulating substrate of the upper resistor sheet, or made of a polymer shown in Table 2. The protective sheets were laminated, and in the same manner as in Example 1, the resistance change between the electrodes of the upper resistance sheet and the pen pressure sensitivity were measured, and the deformation of the protective sheet was observed. The results are shown in Table 2.

[Table] Marked and × indicate significant permanent deformation and wear.

[Table] It is clear that in the tablet for inputting plane coordinates according to the present invention, there is substantially no permanent deformation or wear on the protective sheet, and the resistance value of the resistance sheet is constant.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a resistance sheet.
FIG. 2 is an exploded perspective view showing an embodiment of the tablet for inputting planar coordinates according to the present invention, and FIGS. 3 to 7 are process diagrams showing the manufacturing process of the tablet for inputting planar coordinates shown in FIG. FIG. 7 is a sectional view showing a preferred embodiment of the resistance sheet according to the present invention. 3... Main resistor layer, 4, 4A, 4B... Insulating substrate, 6, 6X, 6Y... Electrode, 7... Protective resistor layer, 9... Resistor layer, 10... Resistance sheet, 1
1...lower resistance sheet, 13...upper resistance sheet.

Claims (1)

[Scope of Claims] 1. A resistor sheet having a resistor layer on an insulating substrate and having strip-shaped electrodes on two opposite edges, the resistor layer being opposite to each other through a pressure-sensitive conductive sheet. In a planar coordinate input tablet that is stacked so as to face each other and detects the position coordinates of a pressure input point on a resistance sheet by an electrical signal, the insulating substrate has a thickness of 80 to 500 μm and a tensile modulus of elasticity of 80 to 500 μm. 1×10 ³ ~20×10 ³ Kg/cm ² , yield point strength 200
~800Kg/ ^cm2 polyamide, polyamide copolymer,
1. A tablet for inputting planar coordinates, comprising a sheet of at least one kind of polymer selected from fluororesin and acrylic-epoxy resin copolymer. 2. Claim 1, characterized in that the resistance sheet consists of a main resistor layer made of a metal thin film provided on an insulating substrate, and a protective resistor layer covering the surface of the main resistor layer. A tablet for inputting plane coordinates as described in Section 1. 3. The tablet for plane coordinate input according to claim 2, wherein the main resistor layer is made of a metal thin film formed by electroplating. 4. The tablet for plane coordinate input according to claim 2, wherein the protective resistor layer is a mixture of carbon or metal powder and synthetic resin. 5. Planar coordinate input device according to claim 2, 3, or 4, characterized in that the sheet resistance value of the protective resistor layer is 10 times or more the sheet resistance value of the main resistor layer. Tablet. 6 A resistor sheet having a resistor layer on an insulating substrate and having strip-shaped electrodes on two opposing edges is stacked with a pressure-sensitive conductive sheet in between so that the resistor layers face each other. In the planar coordinate input tablet which detects the positional coordinates of a pressure input point on a resistance sheet by an electrical signal, the resistor layer covers a main resistor layer made of a metal thin film and its surface. The main resistor layer has a thickness of 80 to 500 μm, a tensile modulus of elasticity of 1×10 ³ to 20×10 ³ Kg/cm ² , and a yield point strength of 200.
~800Kg/ ^cm2 polyamide, polyamide copolymer,
Polyamide or polyamide copolymer bonded to an insulating substrate made of at least one polymer sheet selected from fluorine resin and acrylic-epoxy resin copolymer, and having a tensile modulus higher than that of the insulating substrate. 1. A tablet for inputting planar coordinates, characterized in that a protective sheet made of at least one kind of polymer selected from polymers, fluorine resins, and acrylic-epoxy resin copolymers is laminated on the insulating substrate. 7. The tablet for plane coordinate input according to claim 6, wherein the main resistor layer is made of a metal thin film formed by electroplating. 8. The tablet for plane coordinate input according to claim 6, wherein the protective resistor layer is a mixture of carbon or metal powder and synthetic resin. 9. Planar coordinate input device according to claim 6, 7, or 8, characterized in that the sheet resistance value of the protective resistor layer is 10 times or more the sheet resistance value of the main resistor layer. Tablet.