JPH10275541A - Resistant film type transparent touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the damage resistance and abrasion resistance of a resistant film due to the sliding of a pen (input) in a resistant film type transparent touch panel. SOLUTION: Non-reactive silicon oil (for example, di-methyl silicon oil having viscosity at 200 centipoise) is adhered (at about 10-300 Å) for interposition in a resistant film 3 surface provided on a transparent board 1. A hard coating layer 2 as a bedding layer can be provided between the transparent board 1 and the resistant film 3. Abrasion resistance is improved at about 30% in comparison with a conventional one, in which the silicon oil is not adhered for interposition, and furthermore, transparency is improved a little.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistive transparent touch panel having improved scratch resistance and abrasion resistance.

[0002]

2. Description of the Related Art In general, a resistive transparent touch panel (hereinafter simply referred to as a touch panel) has a conductive material, for example, indium tin oxide (ITO) on one surface of a flexible transparent film substrate (for example, PET film) on the touch side.
And a resistive film is provided on one surface of a rigid transparent plate substrate (eg, a glass plate or a transparent plastic plate) on the display side in the same manner as described above. This is a flat touch panel device obtained by placing and setting via a spacer (generally, a fine projection made of a transparent resin). The touch panel is
Since it has a function of easily and quickly inputting by pen touch input, it is actively used in combination with a liquid crystal display, a CRT display, or the like.

[0003] When information is input by sliding the pen from the touch side, a particular problem is the durability of the resistive film due to damage or abrasion of the resistive film during long-term use. Therefore, with respect to this durability, improvement has already been attempted by various means. For example, a hard coat layer made of a synthetic resin may be provided between the transparent film on the touch side or / and the transparent base material on the display side serving as a base and the resistive film, or a hard coat layer made of the synthetic resin may be used instead or further. Methods such as providing a silicon dioxide layer on a hard coat layer have been proposed. (For example, JP-A-8-132554)

Further, there is an attempt to improve the durability by increasing the insulating spacers provided between the resistive film surfaces or by providing more insulating spacers.

[0005]

However, whether the method disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 8-132554 or the method using an insulating spacer is required to have a longer durability, In addition to the fact that the touch panel is not sufficiently satisfactory, these methods have the following new problems, and a touch panel that is entirely satisfactory has not been obtained. In other words, the transparency and visibility (small eye fatigue and easy to see) required for the touch panel are in the direction of deterioration, and the pen touch input operation is not performed smoothly, especially in the case of the method using insulating spacers. There is a problem in the quality of the touch panel, for example, the spacer itself is clearly observed on the screen.

[0006] In view of the above problems, the present invention has been assiduously studied to further improve the durability of a resistive film based on pen sliding without deteriorating transparency, visibility, and the like. To find the solution.
This can be easily achieved by taking the following measures.

[0007]

That is, the touch panel according to the present invention is characterized in that a non-reactive silicone oil is adhered and interposed on the surface of a resistive film provided on a transparent substrate. Hereinafter, the present invention will be described in more detail.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a touch panel according to the present invention is a flat device generally constructed as described above, and can be classified into three types, an analog type, a matrix type or a hybrid type, depending on the pattern of a resistive film. ,
The touch panel here is not specified by the method. In the analog method, a resistive film is provided in a planar shape on a transparent substrate, whereas in the matrix method, a resistive film is provided in a strip shape on a transparent substrate, and the resistive films are arranged opposite to each other in a matrix (crossover). It was done. In the hybrid system, a strip-like transparent substrate is provided on one of the touch side and the display side, and a sheet-like resistive film is provided on the other side.

Further, the types of the transparent bases forming the touch side and the display side are not specified. In other words, the touch side has a transparent film base (thickness of about 50
About 200 μm). Specifically, a PET (biaxially-stretched polyethylene terephthalate) film is generally used, and other examples include polyethylene naphthalate, polyarylate, polycarbonate, polyether sulfone, amorphous polyester, and amorphous polyolefin. Each film is also used.

On the other hand, unlike the transparent substrate on the touch side, the display side is a rigid transparent plate, that is, a glass plate having a thickness of about 1 mm, which does not bend at least following a touch input operation in response to the pressing. used. Recently, however, transparent plastic plates such as polymethyl methacrylate, diethylene glycol bisallyl carbonate or other polycarbonates, poly (4-methylpentene-1), polystyrene or copolymers of styrene and methyl methacrylate have also been considered as substrates. It became so. That is, the type of each transparent substrate is not specified as long as it is effective as a touch panel. The term “transparent” generally means a total light transmittance of about 80% or more, but is not limited thereto.

The resistive film provided on the transparent substrate is made of a conductive material such as ITO which is generally used as described above, and is then thinned by a thin film forming means such as sputtering. (Approximately 30 nm). The conductive material and the forming means are not specified. The resistance film may be provided directly on the transparent substrate or may be indirect. Here, "indirectly" means that a material having a higher hardness than the hardness of the transparent substrate itself to be used is coated on the transparent substrate in advance. That is, it means that a hard coat layer is provided, and this is used as a base layer, and the resistance film is provided thereon.

Examples of the high-hardness material forming the hard coat layer include generally used transparent curable resins such as acrylic, silicone and urethane which are cured by heat or ultraviolet rays. And the like. The inorganic hard coat layer is formed by forming silicon dioxide or the like by a thin film forming means such as sputtering, or coating perhydropolysilazane (for example, a low-temperature curing type manufactured by Tonen Co., Ltd.) and then heating to decompose the polysilazane. To form a silicon dioxide film. The thickness of the hard coat layer varies depending on the type of the substance, but it is desirable that the thickness is as thin as possible as a whole. This is because, as the thickness increases, the transparency, visibility, and durability of the touch panel due to cracks tend to decrease. In general, it is better to target about 3 to 8 μm for the transparent curable resin and about 10 to 55 nm for the insulating inorganic substance.

As described above, the effect of the non-reactive silicone oil according to the present invention is not limited to the presence or absence of the hard coat layer, but the larger effect is the surface of the resistive film having this layer as a base.

Next, the non-reactive silicone oil will be described. First, silicone oil is generally a polymer having a linear organosiloxane structure represented by the following general formula. Depending on the degree of polymerization n, silicone oil has a wide range of viscosity from low to high (generally 25).
0.6 to several hundred thousand centipoise at a temperature of ° C.

[0015]

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In the above general formula, each R is a substituent, and the properties vary depending on the type of the substituent. Among such silicone oils, in the present invention, it is specified as non-reactive, but this non-reactivity depends on the type of R and does not change with time, which means that it is chemically stable. The non-reactive R is, for example, a case where all of them are alkyl groups such as a methyl group and an ethyl group, or a case where a part of the alkyl groups is a phenyl group, a chlorophenyl group, a fluorinated alkyl group or the like. Therefore, those in which R contains a functional group such as an alkoxy group, an epoxy group, a carboxyl group, an acetoxy group, an amino group, and a hydroxy group are reactive and chemically unstable. Therefore, even if these are oily, the effects of the present invention cannot be obtained. This not only does not provide as effective abrasion resistance as non-reactive silicone oils,
Erosion of the resistive film itself, coloring and reducing transparency,
Furthermore, the viscosity itself changes (is higher) and does not exist stably between the resistive films.

Since the viscosity is in a wide range as described above, it is better to determine the viscosity by conducting various preliminary experiments. In this case, in particular, the adhesion to the resistive film surface (easiness of application) The final decision should be made in consideration of factors such as uniformity of application, the effect of adhesion on transparency, and the effect on input and release in a touch input operation (whether there is a delay in response). Considering this point, it is not preferable that the temperature is too low or too high. In general, it is better to study with a target of about 10 to 10000 centipoise.

The non-reactive silicone oil is specifically preferably a dimethyl silicone oil in which all of R in the above general formula are methyl groups, for example, R is 2 in the main chain.
Phenyl groups are bonded, and the other Rs are methylphenyl silicone oils, all of which are methyl groups, and further, one of the main chain Rs is bonded to, for example, a fluorine atom-substituted propyl group, and all other Rs are methyl groups. Certain propylmethylsilicone oils (one type of fluorosilicone oil) are mentioned. In general, one type is used, but a mixed silicone oil in which two or more types are appropriately mixed may be used. Regarding the use of a mixture, even if they are of the same type or different types, they may be mixed silicone oils obtained by adjusting the viscosity by appropriately mixing those having the same or different viscosities.

Next, a description will be given of how the non-reactive silicone oil is adhered to the surface of the resistive film. First, here, the adhesion intervening means that the resistive film surface on the touch side, the resistive film surface on the display side, or along both surfaces is applied as thinly and uniformly as possible and interposed between the two resistive films. To put. Therefore, it does not mean that an excessively thick film is interposed. If the film is thicker than necessary, coating unevenness is likely to occur, and fine dots, which are insulating spacers, will become apparent and observed, making it difficult to view the screen. This state is observed in the higher viscosity silicone oil. Furthermore, when an attempt is made to input with a lighter touch, the contact is likely to be unstable, making it difficult to quickly and accurately respond. In view of the meaning of such adhesion, an appropriate film thickness may be determined by a preliminary experiment, but generally, a target of about 10 to 300 °, preferably 20 to 200 ° is good.

The means for applying the non-reactive silicone oil is performed by a commonly used coating method such as spraying, rolling, and spinning. At the time of coating, the silicone oil may be directly used for coating when the viscosity is low, but when it is difficult to coat quickly and uniformly with a high viscosity and a desired film thickness,
It is preferable to dilute with an organic solvent such as toluene or xylene and adjust the viscosity to an appropriate value before use. In addition, since a small amount of water may be contained in the silicone oil, it is preferable to use the silicone oil by vacuum drying in advance. The adhesion coating may be performed on the resistive film surface on the touch side, the resistive film surface on the display side, or both resistive film surfaces, but is preferably performed only on the resistive film surface on which no insulating spacer is provided.

When the insulating spacer is not touched (released), the two resistive films maintain a completely insulated state. Conversely, in a touch input operation, even a light touch makes it easy to make a conductive state. It is necessary for And it is generally provided on the resistive film surface on the touch side or the display side.Specifically, for example, using a curable transparent acrylic resin on the resistive film surface provided on the touch side or the display side, this is screened. By a method such as printing, fine dots (for example, a contact area of about 0.001 to 0.003 mm ² ,
Is printed at a pitch of about 2 to 5 mm, and is cured and fixed.

The effects of scratch resistance and abrasion resistance on the surface of the resistive film by the non-reactive silicone oil according to the present invention are considered to be due to the following effects. First, scratches and abrasion generally occurring on the resistive film surface are considered to be due to the following mechanism. When the touch input surface is pushed and slid with a pen (typically, a polyacetal tip having a radius of 0.8 mm), the following two functions work between the resistive films. In other words, one of them is that the resistive film originally has a slight tackiness, and when the two resistive films come into contact with a pen touch, the resistive film is momentarily brought into close contact. The repetition of the close contact and the release (stopping the touch operation) causes damage (peeling of the resistive film) at that portion. Another effect is skidding. In this case, when the pen is slid left and right, a slight side slip occurs between the resistive films, and the resistive film is worn by the repetition of the slip.

Therefore, if the silicone oil adheres to the surface of the resistive film, tackiness of the resistive film disappears first, and the instantaneous adhesion action is completely eliminated, so that scratches due to the tack are eliminated. On the other hand, skidding is extremely slippery because the oil film of the silicone oil is always interposed, so that friction between the two resistive films is reduced. It does not act as a force of wear. In addition, since the silicone oil is attached and interposed, there is no electric insulation between the two resistive films even when touched.

[0024]

EXAMPLES The present invention will be described in more detail with reference to Examples along with Comparative Examples. In this example, the wear resistance was evaluated by checking the wear resistance. The evaluation was performed based on the number of reciprocal slidings measured by the following method. The larger the number, the better the wear resistance. That is, using a pre-assembled touch panel, a pen (polyacetal nib having a radius of 0.8 mm) is used to apply a weight of 2
Slide the same place under 90g horizontally and left and right about 40mm. Then, the occurrence of whitening of the resistive film is confirmed while observing with the naked eye, and the number of reciprocal sliding at the time when the whitening starts is known.

Example 1 First, a transparent PET film substrate having a thickness of 100 μm and a size of 150 × 200 mm and a transparent polycarbonate substrate having a thickness of 1.0 mm and a size of 150 × 200 mm were prepared. A hard coat layer was formed by coating a thermosetting transparent silicone resin on both surfaces of each film so as to have a thickness of 5 μm, respectively, to form an underlayer. Next, on one surface of each of the obtained hard coat layers, ITO was sputtered under the following conditions to form a 300-mm-thick resistive film in close contact with the entire surface. Sputtering method: DC magnetron sputtering target: ITO sintered body Sputtering substrate temperature: 100 ° C. Ultimate vacuum: 7 × 10 ⁻⁶ Torr Sputtering operation pressure: 2.0 × 10 ⁻³ Torr (Ar gas containing 4.5% oxygen) Input power: 0.8 kw Sputtering time: 20 seconds

Next, on the surface of the ITO resistive film on the transparent polycarbonate substrate obtained above, fine projections (ground area of 0.1 mm) were formed by screen printing using a transparent acrylic photosensitive resin.
(002 mm ² , height 5 μm) was printed in a grid pattern at a pitch of 3 mm, and then irradiated and irradiated with ultraviolet rays, and fixed by adhesion. An insulating spacer was planted on the entire surface. The substrate thus obtained is called a display-side substrate.

On the other hand, the surface of the ITO resistive film formed on the transparent PET film substrate is spray-coated with a xylene solution obtained by dissolving 5% by weight of dimethyl silicone oil having a viscosity of 200 centipoise, and then the xylene is dried and removed. To deposit dimethyl silicone oil. At this time, the film thickness was 200 °. The substrate obtained in this manner (converted from the adhesion amount, the adhesion area, and the specific gravity) is referred to as a touch-side substrate.

Then, a double-sided tape having a thickness of 100 μm and a width of 3 mm is adhered to the entire peripheral edge of the obtained display-side substrate on the side of the resistive film, and then the resistive film surfaces are opposed to each other. Then, they were bonded and fixed, and assembled into a flat touch panel.

The assembled flat touch panel is shown in FIG. 1 (side sectional view). In the figure, 1 is a PET film substrate (touch input side), 2 is a hard coat layer, 3 is I
A TO resistance film, 4 is a dimethyl silicone oil adhered film, 5 is a double-sided tape, 6 is a polycarbonate substrate (display side), and 7 is an insulating spacer.

Then, the outer surface of the flat touch panel on the touch-side substrate side was slid with a pen to check wear resistance. As a result, 150,000 reciprocations (300,000 one-way) reciprocations caused slight, but slight, streaking of the resistive film on the touch-side substrate. Therefore, the abrasion resistance was determined to be 150,000 times.

Example 2 Example 1 was repeated except that dimethyl silicone oil was used instead of dimethyl silicone oil.
A flat touch panel was prepared in the same manner as in Example 1 except that fluorinated propylmethylsilicone oil was used, and the abrasion resistance due to pen sliding was checked in the same manner as in Example 1.
However, the concentration of the silicone oil was 3% by weight, and a solution dissolved in xylene was coated with a spin coater and dried. The film thickness adhering thereto was 150 °. No whitening of the resistive film was observed even when the number of times of sliding was 160,000. The abrasion resistance was judged to be 160,000 times or more.

Example 3 A flat touch panel was prepared under the same conditions as in Example 1 except that methylphenyl silicone oil having a viscosity of 22 centipoise was used instead of dimethyl silicone oil, and pen touch sliding was performed. The wear resistance of the resistive film was checked. However, the silicone oil was a 20% by weight xylene solution, coated with a spin coater, and dried to adhere the silicone oil film. The film thickness was 270 °. Slight whitening was observed when the number of times of sliding measured was 150,000 times. The abrasion resistance was determined to be 150,000 times.

(Comparative Example 1) A flat touch panel obtained in exactly the same manner as in Example 1 except that no dimethyl silicone oil was attached and interposed was used to check the abrasion resistance due to pen sliding as in Example 1. Result 11
At the 10,000th time, white streaks appeared on the resistive film on the touch side. Therefore, the abrasion resistance was 110,000 times.

The transparency (total light transmittance%) of the flat touch panels obtained in Examples 1 to 3 and Comparative Example 1 was checked.
It was also confirmed that it improved by 0.4%.

Comparative Example 2 (When Reactive Silicone Oil was Adhered and Interposed) In Example 1, one carboxyl group was substituted at both terminals (R3 in the above formula) instead of dimethyl silicone oil. A flat touch panel was manufactured under the same conditions except that a carboxyl-modified silicone oil (viscosity: 100 centipoise) was adhered and interposed, and the wear resistance of the resistive film was checked in the same manner as in this example. However, the silicone oil was dissolved in xylene at a concentration of 6% by weight, coated with a spin coater, dried and adhered. The deposited film thickness was 180 °. The number of times of pen sliding was 130,000 times, which was larger than that of Comparative Example 1. However, in addition to being smaller than that of Examples 1 to 3, the color was slightly yellowish, and this color increased with time. did. Further, when the screen input operation on the display was performed after about one month had passed, there was an error in the position detection.

[0036]

Since the resistive transparent touch panel of the present invention is constituted as described above, the following effects can be obtained. First, with the conventional means, the scratch resistance and abrasion resistance of the touch panel against pen sliding, which had been limited, are remarkably improved, and a touch panel with higher performance can be manufactured.

Further, the transparency of the touch panel is not deteriorated but rather improved. Of course, because it is a non-reactive silicone oil, viscosity due to temperature change,
There is no chemical change and it exists stably on the resistive film surface.
Therefore, the quality and performance of the touch panel do not change in the environment and do not change with time.

[Brief description of the drawings]

FIG. 1 is a configuration side sectional view of a flat touch panel according to a first embodiment.

[Explanation of symbols]

 1. 1. PET film substrate Hard coat layer 3. 3. ITO resistive film 4. Dimethyl silicone oil adhering film Double-sided tape 6. 6. polycarbonate substrate Insulating spacer

Claims (5)

[Claims] 1. A resistive transparent touch panel characterized in that a non-reactive silicone oil adheres to and adheres to a resistive film surface provided on a transparent substrate. 2. The resistive transparent touch panel according to claim 1, wherein the transparent substrate has a hard coat layer as a base layer. 3. The transparent touch panel according to claim 1, which is a non-reactive silicone oil having a viscosity of 10 to 10,000 centipoise. 4. The resistive transparent touch panel according to claim 3, wherein the non-reactive silicone oil is one of dimethyl silicone oil, methyl phenyl silicone oil, and fluorosilicone oil. 5. The method according to claim 1, wherein the non-reactive silicone oil is from 10 to 300.
5. The method according to claim 1, wherein the film is attached with a thickness of Å.
Item 8. The resistive transparent touch panel according to item 1.