JPH08332649A - Production of base plate for transparent touch panel - Google Patents

Abstract

PURPOSE: To always efficiently obtain a desired base plate of stable quality by making it possible to integrally mold a base panel for a transparent touch panel at a stroke by injecting a transparent resin in a mold for the base panel for the transparent panel provided with fine uneven parts for preventing a Newton ring. CONSTITUTION: Four core pins 4 are vertically provided to a cavity 1 having fine unevenness side by side and receiving holes 7 are provided on the core 2 covering the cavity 1 corresponding to the core pins 4. This mold is set at the leading end of an injection molding machine and pellets of sufficiently dried polymethyl methacrylate are extruded from a molding machine to obtain a sheet like molded body. In a set transparent touch panel, two electrodes 9, 10 and four holes for drawing out the electrodes 9, 10 to the outside are provided on a transparent polymethyl methacrylate substrate 8 becoming a non-touch side and a touch substrate 15 is set on the substrate 8 in opposed relationship by an insulating tape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a transparent touch panel substrate at once by using a specific transparent touch panel substrate mold.

[0002]

2. Description of the Related Art As a transparent touch panel, a polyethylene terephthalate (PET) film is used as a touch side (pressing side) substrate, a glass plate is used as a non-touch side (display side) substrate, and ITO (oxidized) is formed on one surface of each. There is a combination in which a resistance film made of indium, tin, or the like is provided, and the resistance films are arranged so as to face each other via an insulating spacer. Here, in order to derive an input current that is touch-input from the touch-side substrate and connect it to another circuit (terminal device or the like), an FPC lead wire may be taken out from the side surface of the panel to the outside.

Input on the touch panel is performed by pressing the touch-side substrate with a pen or a finger, but it is also required that the plane be smoother because transparency is important. However, the smoothness also means that the touch-side and non-touch-side substrates are easily attached on the touch surface. If they are easily attached, Newton's rings are likely to occur around the surface (point). The Newton's ring is a stripe pattern due to optical interference, which is a problem in terms of the quality of the transparent touch panel. In order to prevent this Newton's ring, it is known that fine particles of 3 to 100 μm are deposited and distributed (for example, 300 to 3000 particles / inch ² ) on the surface of the touch side substrate or the non-touch side substrate by a spray method or the like. This content is disclosed in JP-A-62-7.
It is introduced in Japanese Patent No. 6118.

Further, a lead wire using an FPC for extracting an input current touch-input from the touch-side substrate and connecting it to another circuit (for example, LCD) is taken out from the side surface of the transparent touch panel to the outside. .

Further, the touch side and non-touch side substrates are generally used by cutting an original fabric or an original plate which has been made into a product in advance into a desired size.

[0006]

First, when the inventors of the present invention retested the measures against the Newton's rings found in the above-mentioned Japanese Patent Laid-Open Publication No. Sho, the occurrence of the Newton's rings is certainly suppressed, but the transparency tends to decrease. Seen again, 50 μm
Fine particles of a certain size or larger result in an extremely rough coating surface, which also causes a decline in the function of the touch panel. Further, there are various drawbacks such as the necessity of a separate step of coating and the difficulty of uniform coating over the entire surface and easy occurrence of variations.

The FPC lead wire pulled out from the side surface of the transparent touch panel may be broken during handling, or it may be difficult to make it compact because it requires space.
Further, there is a problem that an amateur cannot do it if he / she wants to replace the panel with a new one.

Further, when cutting each substrate into a desired size from the original fabric or original plate, there is a need for a separate process of cutting, and chips and cutting loss are unavoidable.

The present invention has been found as a result of intensive studies on the above problems. A first object of the present invention is to provide a method for manufacturing a transparent touch panel substrate on which Newton's rings are prevented by molding at once. In offer. The second purpose is to provide a method for manufacturing the substrate to which the electrode drawing means is further added in the same manner, and the third purpose is light weight, easy to handle, and replaceable with a new one by an amateur. To provide a transparent touch panel.

[0010]

In order to achieve the first object, first, a transparent resin is injected and molded into a mold for a transparent touch panel provided with fine Newton's ring preventing fine concavo-convex portions to form a Newton's ring. It is characterized by producing a transparent touch panel substrate having a fine uneven surface for prevention. This will be described in detail below.

A mold is required for manufacturing the desired transparent touch panel substrate itself. The mold basically comprises a cavity (female) and a core (male), and a void is formed therein. Since the transparent touch panel substrate is manufactured by injecting the transparent resin into the void, basically, by changing the size of the void (length x width x depth), the touch side of the same size or The non-touch side substrate can be manufactured. The size (vertical x horizontal) of the touch-side substrate and the non-touch-side substrate varies depending on the purpose and application, so the size of the void portion may be changed accordingly, but generally the thickness of the touch-side substrate is about 0. 1 to 0.25
mm, and the non-touch side substrate is about 0.25 to 5 mm, so the depth of the void portion may be determined based on this.

As described above, the size (length × width × thickness) of each substrate is basically determined by the size of the void, but in general, resin has molding shrinkage. It is desirable to design the mold by using Further, the transparent touch panel substrate referred to here is a substrate on the touch side and / or the non-touch side.

According to the present invention, it is necessary to simultaneously manufacture each of the above-mentioned substrates by a die at the same time, and at the same time, to provide fine irregularities for preventing Newton's rings on the substrate surface. A fine concavo-convex portion is also provided in the mold, that is, on the cavitation or core surface. By forming the fine irregularities, the generation of Newton's rings at the touch points (surfaces) of the transparent touch panel is eliminated, but it is not desirable that these fine irregularities are too small, or conversely too large. However, it is desired to be within the proper range. This range has a cutoff value of 0.8 mm
The center line average roughness (hereinafter referred to as Ra) is 0.05 to 2 μm, preferably 0.1 to 1 μm.

The cut-off value generally refers to the degree of surface waviness, but in the present invention, it refers to the distance between peaks and valleys or valleys and valleys of fine irregularities. Since it is not preferable that the distance is too large or too small, the above range is exemplified as a desirable range.

Ra is the degree of minute irregularities (depth) uniformly and uniformly applied to the entire surface. Ra is 0.05 mm.
When it is less than 2, the transparency is rather deteriorated rather than the generation of Newton rings, and when it exceeds 2 μm, the generation of Newton rings is observed, which is not preferable.

The shape of fine irregularities for preventing Newton's rings,
The arrangement state is not particularly limited. For example, it is regularly or irregularly arranged in a cylindrical shape, a conical shape, a prismatic shape, a rectangular shape, a cubic shape, or a mixed shape thereof.

The Newton's ring preventing fine unevenness formed on the transparent touch panel substrate is formed on the touch side substrate and / or the non-touch side substrate, but either one is preferable in consideration of the influence on the transparency. . However, in the touch-side substrate, the irregularities may be formed on both surfaces thereof. In this case, the uneven surface serving as the upper surface serves to prevent the surrounding object from being reflected on the touch surface. The low light reflection effect makes it difficult to see and operate. In addition, as a countermeasure for this reflection, by providing fine unevenness for Newton ring prevention on the non-touch substrate side and combining the fine uneven surface provided on the touch side substrate as the upper surface, it is possible to prevent Newton ring and also prevent reflection. Become.

There is no particular limitation on the means for producing the fine Newton's ring preventing fine unevenness in the mold. Examples include photoengraving / etching, electrical discharge machining, sandblasting, and the like. Here, the photoengraving / etching method is the cavitation of the mold, or the negative surface of the pattern of the desired unevenness by coating the surface of the core with a photosensitive solution, or the positive type film is masked, exposed and developed, and then ferric chloride. The method is etching with an aqueous solution of nitric acid or the like, and the electric discharge machining is a method in which electric discharge is performed through a mother die in an insulating liquid. Therefore, since both are performed through a mask, they are regularly made in a predetermined shape and size. On the other hand, sandblasting
The arrangement is random and random. Preliminary testing should determine which is the appropriate method.

Using the mold thus obtained, a transparent resin is injected into the mold to integrally form a transparent touch panel substrate on which desired Newton ring preventing fine irregularities are formed.
Here, the resin and the injection molding are as follows.

First, the resin is a synthetic resin having excellent transparency and melting or softening at a predetermined temperature.
Here, the transparency is an indispensable condition for a touch panel substrate, and it means that the total light transmittance is higher (for example, 80% or more) than the haze value is smaller (for example, 5% or less). Of course, it is desirable that the strength, heat resistance, and chemical resistance are excellent, but the hardness is also high (for example, Rockwell hardness is 60 or more, preferably 70).
Or more) is preferable. It is desired that the hardness be higher, especially in the touch side substrate. This is to improve scratch resistance in the case of pen touch.

Therefore, any existing resin can be used as long as it satisfies the above conditions. Amorphous polyester (for example, Eastman Chemical Company Easter), polymethylmethacrylate, polycarbonate, diethyleneglycolbisallylcarbonate, polystyrene, styrene / acrylonitrile copolymer, copolymer with styrene / methylmethacrylate, polyvinyl chloride , Polysulfone,
Examples thereof include polymethylpentene, an acryl-imide polymer (for example, Caymax manufactured by Sumika Hercules Co., PMI resin manufactured by Mitsubishi Rayon Co., Ltd.), and a blend polymer mainly composed of syndiotactic polypropylene. In the thermosetting resin, if there is one that meets the above conditions at the prepolymer stage, the resin can also be used, but in such a case, molding is performed by injecting into a mold at the prepolymer stage and performing post-curing. Needs heating.

There are no special conditions for the injection molding method, and the method is generally used. For example, if a non-touch side substrate is to be manufactured using polymethylmethacrylate, a mold provided with Newton's ring preventing fine concavo-convex portion on the cavitation side is first attached to a screw type extruder. The resin pellets are 80 to 95 ° C
Vacuum dry for about 4 to 6 hours to completely remove water.
Then, the barrel temperature of the extruder is set to 220 to 270.
C. and a mold temperature of 50 to 90.degree. When the amount for molding the substrate is supplied, the substrate is stopped, cooled, and knocked out to automatically take out.

Further, as means for achieving the second object, in addition to the Newton ring preventing fine irregularities, a core pin for an electrode drawing hole is provided in a mold, and a transparent resin is injected in the same manner as described above. The substrate for a transparent touch panel manufactured by molding has fine projections and depressions for preventing Newton's rings and electrode lead holes.

The electrode lead-out hole is provided in the peripheral portion of the transparent touch panel. This is because the lead-out electrode provided in the panel hits the peripheral edge portion, so that the core pin for making the hole is also hung vertically at a corresponding position. As described above, the holes are for extracting the electrodes to the outside, and thereby the FPC lead wires from the side surfaces of the panel, which are generally performed, are completely removed.

The core pin is hung on either the cavity or the core of the mold, the number of which depends on the required electrode lead hole. The number of holes is generally determined by the function of the transparent touch panel (by function). The method includes an analog method, a matrix method, and a combination method of both. For example, in the analog system, the touch-side and non-touch-side substrates require electrode holes of 2 holes (4 wire type) or 4 holes (8 wire type) respectively, so the core pin is 2 or 4 Need. In the matrix method, the holes are required for the number of strip-shaped resistance films, and therefore the core pins corresponding to the holes may be provided vertically. The shape of the core pin is generally a cylinder of about 1 to 3 mmφ, but it may be an ellipse, a prism, or the like.

The touch-side or non-touch-side transparent resin substrate obtained by injection molding with the mold provided with the core pin has a required number of holes, so that the holes are made conductive and the terminals are connected from there. Wired to connect to equipment. However, the holes can also be brought together on either the touch side or the non-touch side of the substrate, which is preferred in some cases. That is, for example, in the case of the analog system of the 4-wire type, four holes are provided in either one, and in the case of the 8-wire type, eight holes are provided in either one. Therefore, the number of core pins vertically provided in the mold is four or eight.

The holes provided in the substrate can be electrically connected to the electrode portions by injecting a conductive paste into the holes, plating with copper or the like, or sputtering.

In the transparent touch panel substrate manufactured as described above, there is no electrode lead-out hole, or the substrate formed by the injection molding of the present invention has either a touch side or a non-touch side. In some cases. In such a case, a transparent touch panel substrate having the above-mentioned function is separately prepared by a method generally used in the past, and the transparent touch panel substrate is combined with any one of the substrates prepared according to the present invention. It can also be assembled and used as.

Although the number of the molds may be one, it is preferable to provide a plurality of molds through a runner and mold a large number at a time. The cavities and the cores forming the mold may be either movable or fixed, but the cavities are preferably fixed.

Although the transparent touch panel substrate is finally assembled as a transparent touch panel and is framed by an aluminum chassis or the like, in order to quickly and reliably fix the chassis to the chassis or the like at a fixed position. An edge is provided on the substrate, and a fixing means, for example, a mounting projection, is attached to the edge portion,
A hook for fixing by hooking, or a method for fixing the edge portion with an adhesive may be adopted. Of course, in the case of providing such fixing means, it is advisable to attach the fixing means to the mold and perform the injection molding at once.

[0031]

The Newton's ring, that is, the stripe pattern due to optical interference does not occur, because two or more waves (light) having the same wavelength or a wavelength close to that at the touch point are scattered by the fine unevenness at the touch point. And as a result, it is considered that the waves do not overlap and do not interfere.

Further, since the innumerable minute irregularities are constantly and consistently formed on the resin substrate by integral molding using a transparent resin die, there is no variation in quality and performance among products.

[0033]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Example 1 An iron-based cavitate having a depth of 3.0 mm, a length of 200 mm, and a width of 250 mm was prepared, and its inner surface was mirror-finished to have a Ra of 0.03 μm or less. Next, the mirror-finished surface was thinly coated with an acrylic photosensitive resin and dried to sensitize it. On the other hand, a 600-line flat mesh positive film made of square dots was prepared, which was vacuum-adhered to the photosensitive surface of the cavitation and exposed to ultraviolet rays, and after alkali development, it was not etched by an aqueous ferric chloride solution. Corroded exposed areas. The resist film was removed, washed thoroughly with water and dried. During the etching, sufficient care was taken to prevent the ferric chloride aqueous solution from contacting the surface other than the photosensitive film surface.

The fine irregularities obtained by the etching were measured with a surface roughness profile measuring instrument, Surcom 570A (manufactured by Tokyo Seimitsu Co., Ltd.), and the cutoff value was 0.08 μm.
Ra was 0.93 to 1.10 μm. This is the fixed-side template.

On the other hand, 2.8 in close contact with the cavitation.
A 0.2 mm-deep core with a cavity depth of 0 mm was prepared using the same material as the cavitation. The core is also Ra0.
A mirror finish was performed so as to have a thickness of 03 μm. This is the moving side template.

A transparent resin gate, a projecting pin, and an air vent were provided on the cavitation, and the cavity was set at the tip of an injection molding machine together with the core, and injection molding was performed under the following conditions. Using sufficiently dried amorphous polyester Easter PETG (manufactured by Eastman Chemical Company) pellets as a transparent resin, the barrel temperature is 90 to 120 ° C, and the temperature of the cavities and the core, which are the molds, is 40 ° C. Adjust to 50
0 sheets were molded. The obtained molded product was a transparent film having a thickness of 0.19 mm, a length of 198.5 mm and a width of 249.5 mm.

When the roughened surface of the molded film was measured with the Surcom 570A type measuring machine, the cutoff value was 0.08 mm and the Ra was 0.91 to 1.08 μm, which was almost the same as the fine irregularities of the mold. Rockwell hardness (D78
5) was R107. Hereinafter, this is referred to as a touch-side film substrate.

On the other hand, the thickness of the non-touch side substrate is 1.0 m
A glass plate measuring m, 198.5 mm in length, and 249.5 mm in width is prepared, and one side of the glass plate is attached to the fine uneven surface of the touch side substrate.
Sputtering of TO was performed to form a resistance film on each. Furthermore, regarding the glass plate, a diameter of 3
An insulating spacer in which dots of 0 μm and a height of 10 μm were arranged in a grid pattern at a pitch of 3 mm was formed of an ultraviolet curable acrylic resin.

The two substrates were set around each other with an insulating tape having a thickness of 20 μm and a width of 3 mm being superposed on each other, and the occurrence of Newton's rings was checked. The touch-side film substrate was pressed with the fingertip and the pen, but no Newton ring was observed in any case.

Example 2 Using the cavitation of Example 1, a height of 3.5 mm,
Four core pins made of stainless steel with a diameter of 1.5 mm were vertically installed and fixed in a side-by-side manner at a pitch of 3 mm around the side. On the other hand, the core was made of the same material as the cavitation so that 0.7 mm could be attached to the cavitation in a close contact state (void depth 2.8 mm). The core was mirror-finished so as to have a Ra of 0.03 μm or less, and provided with receiving holes such that the tips of the four core pins could be easily fitted and removed when the core was attached to the cavities. This is shown in the drawing as the cross-sectional view of FIG. Here, 1 is a cavitation formed with fine irregularities 3 having a cutoff value of 0.08 mm and an Ra of 0.93 to 1.10 μm formed in Example 1, and further includes 4 cavities indicated by 4 (1.5 mmφ, 3 mm). Pitch) core pins are hung horizontally (on the front side). Reference numeral 2 is a core which is crowned in close contact with the cavities and has receiving holes shown in 7 corresponding to the core pins. 5 is a void, 6 is a core 2
FIG. 3 is an imaginary view showing a state in which is removed from the cavitation 1.

The mold shown in FIG. 1 is set at the tip of an injection molding machine, the barrel temperature is controlled to 220 to 260 ° C., the mold temperature is controlled to 65 ° C., and sufficiently dried pellets of polymethylmethacrylate are prepared in the molding machine. Was extruded to obtain 500 sheet-shaped molded products.

The thickness of the obtained molded body is 2.78 mm,
The length is 199.0 mm, the width is 249.3 mm, the diameter of the hole provided is 1.49 mm, and the roughness of the fine uneven surface is measured in the same manner as in Example 1, and the cutoff value is 0.08 mm.
It was also confirmed that Ra was 0.93 to 1.09 μm, and the reproduction was almost the same as that of the mold. Hereinafter, this molded body is referred to as a non-touch side substrate.

Next, with respect to each of the substrates on the touch side and the non-touch side obtained in Example 1, the former is a smooth surface (non-fine concavo-convex surface) and the latter is sputtered with ITO on the fine concavo-convex surface. By doing so, a resistance film (film thickness: 0.05 μm) for an analog system was formed. Sputtering was also performed in the four holes of the non-touch side substrate at the same time, but it was performed using a masking material so as to sputter independently without being connected to the resistance film formed on the uneven surface. . Further, sputtering was performed using a masking material so that the ITO resistance film was not formed around 10 mm around each substrate.

Then, the IT of the obtained non-touch side substrate
After forming insulating spacers on the surface of the O-resistive film, the dots having a diameter of 30 μm and a height of 10 μm arranged in a grid pattern at a pitch of 3 mm with an ultraviolet curable acrylic resin, two electrodes are drawn out from the resistive film. Was provided by screen printing of a silver paste so that two of the four holes were electrically connected. On the other hand, also in the non-touch side film substrate, two electrodes for extraction were provided on the resistance film by silver paste as in the above. In this case, the terminal of the electrode was made to coincide with the remaining two holes of the four holes.

Next, the two substrates were set with their ITO resistance film surfaces facing each other, with an insulating tape having a width of 3 mm and a thickness of 20 μm interposed therebetween. Then, a silver paste was injected into the four holes, and each was connected to the electrode drawn out to the substrate so as to be electrically connected. The transparent touch panel thus set is shown in the side sectional view of FIG. First, 8 is a transparent polymethylmethacrylate substrate which is the non-touch side, and I is provided on the fine uneven surface.
A TO resistance film 11, an insulating spacer 12, two electrodes 9 and 10 drawn out from the resistance film, and four holes for drawing out the electrodes are provided (13, 14, 19, 2).
Corresponding to 0). With respect to the substrate 8, the amorphous polyester touch side substrate 15 molded in Example 1 has a thickness of 20 μm.
It is set oppositely by the insulating tape. Reference numeral 21 is a resistance film provided on the smooth surface of the substrate 15, and 17 and 18 are electrodes extracted from the resistance film 21. Reference numeral 16 is a fine uneven surface, which is made to be the upper surface here and has a meaning for preventing reflection. 13 and 14 are the non-touch side substrate 8
Is a conductor made of silver paste injected into a hole for pulling out the two electrodes 9 and 10 from the outside, and 19 and 20 are two electrodes 17 from the touch side substrate 15,
18 is a conductor made of a silver paste injected into the hole to pull out 18 and outward. LC for these four conductors
It suffices to connect terminal devices such as D. Therefore, it is not necessary to pull out the FPC lead wire from the side surface of the transparent touch panel as in the conventional case. It should be noted that although the drawing shows that there is a void portion, this is only shown for convenience of explanation of the inner surface structure, and in reality, the insulating spacer 1
The gap is the same as or slightly higher than the height of 1.

The transparent touch panels 13 and 1 shown in FIG.
Connect the conductor terminals of 4, 19, and 20 to the leads from the LCD (liquid crystal display) via a connector,
Information was touch-input with a pen to check the overall driving status. As a result, the input information was displayed without any particular problem, and Newton's rings did not occur at all. Furthermore, there is no phenomenon that surrounding objects are projected on the touch surface,
It was easy to see and operate.

[0047]

Since the present invention is configured as described above, it has the following effects.

First, the transparent touch panel substrate on which fine irregularities for preventing Newton's rings are formed is integrally molded at once by injection molding of a transparent resin into a mold. Manufacturing can be quickly and efficiently obtained.

In the transparent touch panel obtained as the final product, there is no Newton's ring at the touch point, that is, no optical interference fringes are generated, so that there is no troublesome operation or quality trouble.

In addition to the Newton's ring prevention measure, the electrode lead-out hole is also formed in the substrate at the same time by the core pin hung vertically in the mold, so that there is no need to separately form a hole for that purpose. By forming a conductor in which the hole connects to the electrode, a wiring structure in which the FPC lead wire is taken out from the side surface of the transparent touch panel as in the conventional case is not taken. This eliminates any risk of wire breaks, especially during handling.

Further, since the electrodes are drawn out by making the holes provided in the substrate electrically conductive, the connection between the electrically conductive holes and the interface board, LCD or the like can be made with one touch, and thus transparent. If the touch panel breaks down or becomes unusable due to the end of its life, it will be easy for an amateur to replace it with a new one.

Further, the reflection of surrounding objects that are likely to appear on the touch-side substrate surface can be prevented by using the fine concave-convex surface upward.

In general, there is no need for separate processes such as cutting, Newton's ring prevention, and drilling, which are advantageous in terms of manufacturing equipment, production management, manufacturing time, etc. in the manufacture of the transparent touch panel itself. Is extremely large.

[Brief description of drawings]

FIG. 1 is a side sectional view of a mold.

FIG. 2 is a side sectional view of a transparent touch panel.

[Explanation of symbols]

 1 Cavitation (according to Example 1) 2 Core 3 Micro unevenness 4 Core pin 5 Void portion 6 Imaginary view of core removed 7 Receiving hole for core pin provided in core 8 Polymethylmethacrylate non-touch side substrate 9 Electrode 10 Same as above 11 ITO resistance film 12 Insulating spacer 13 Conductor (hole) 14 Conductor (hole) 15 Amorphous polyester touch side substrate 16 Fine unevenness 17 Electrode 18 Electrode 19 Conductor (hole) 20 Conductor (hole) Part) 21 resistive film 22 insulating tape

Front Page Continuation (72) Inventor Yukio Murakami 163 Morikawara-cho, Moriyama-shi, Shiga Gunze Stock Company Development Division Electronic Functional Materials Center

Claims (3)

[Claims] 1. A method for manufacturing a substrate for a transparent touch panel, which comprises injecting and molding a transparent resin into a mold for a transparent touch panel substrate provided with a Newton's ring preventing fine concavo-convex portion. 2. A method for manufacturing a substrate for a transparent touch panel, which comprises injecting and molding a transparent resin into a mold for a transparent touch panel substrate, which is provided with fine Newton's ring preventing irregularities and core pins for electrode lead-out holes. . 3. A fine uneven portion for preventing Newton's rings has a cutoff value of 0.8 mm or less and a center line average roughness of 0.05 to 2 μm.
Claim 1 and Claim 2 which consist of innumerable fine irregularities of m.
The method for manufacturing a substrate for transparent touch panel according to.