JP2005038288A - Touch panel glass, and method for manufacturing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a touch panel glass which is excellent in transparency, wear resistance, finger slidability in touching with a fingertip, further has an anti-glare function, and is manufacturable at low cost, and a method for manufacturing it. <P>SOLUTION: This touch panel glass comprises a glass substrate and a transparent layer formed on the glass substrate. The touch panel glass has 10-point average roughness R<SB>z</SB>on the surface of the transparent layer of 0.5-6.0μm, or an arithmetic average roughness R<SB>a</SB>of 0.05-0.20μm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to glass for a touch panel used as a contact surface of a touch panel and a method for manufacturing the same.

  The function of the touch panel is to bring a medium such as a human fingertip or other object into contact with a specific position on the surface of the touch panel and detect the contact position. The method for detecting the contact position is roughly classified into a method using a resistance film and a conductive film and a method using infrared rays, ultrasonic waves or capacitance.

  The method using a resistive film and conductive film utilizes the fact that the resistive film formed on the back surface of the panel comes into contact with the conductive film by pressing the panel surface with a fingertip, and the resistance value of the conductive film changes. is doing. While there is an advantage that it is possible to reduce the size and thickness and to reduce power consumption, there are problems in terms of response time, sensitivity, durability, and the like. Further, since a film is used as the transparent substrate to which the resistance film is attached, there is a problem that the light transmittance is remarkably lowered with the deterioration of the film and the display quality is deteriorated (for example, refer to Patent Document 1).

  On the other hand, in the method using infrared rays, the infrared rays are passed through the transparent substrate substantially parallel to the surface of the transparent substrate, and the position is detected by shielding the infrared rays by contact with a fingertip or the like. Also, the method using ultrasonic waves utilizes the fact that surface acoustic waves are excited on a transparent substrate and the propagation characteristics of the surface waves are changed by contact of a fingertip or the like. Therefore, it is not necessary to form a resistance film or the like, the light transmittance is extremely high, display quality is not deteriorated, and response time, sensitivity, durability, and the like are excellent.

  Conventionally, an anti-glare (AG) function and an anti-reflection (AR) function are added on a transparent substrate used for a touch panel in order to prevent the image on the display surface from becoming difficult to see due to the reflection of a fluorescent lamp. Has been done.

  As a method for adding an AG function, a method of forming a concavo-convex surface on the surface of a transparent substrate by etching treatment with hydrofluoric acid, a method of attaching a plastic film having a concavo-convex surface to the surface of the transparent substrate, and the like are known.

  However, the method of forming irregularities by etching treatment is expensive in terms of manufacturing method, and there are problems that the degree of AG effect is difficult to control. In addition, the method of attaching the plastic film has a problem that the abrasion resistance of the plastic film is low and it is difficult to use for a touch panel that uses ultrasonic waves, which is expected to increase in demand in the future.

  Therefore, in order to add the AR function, a method has been proposed in which fine particles are mixed with a sol solution prepared by a sol-gel method, and a low-reflection film is formed and fired by applying the mixture onto a substrate (for example, (See Patent Document 2). However, since the low reflection film is made porous, there is a problem that the wear resistance is inferior.

Japanese Patent Laid-Open No. 2002-196876

Japanese Patent Laid-Open No. 10-13003

  An object of the present invention is to provide a glass for a touch panel that has excellent finger slipping properties, has an AG function, is excellent in transparency, and can be manufactured at low cost.

That is, the present invention provides the following (1) to (5).
(1) A glass for a touch panel having a glass substrate and a transparent layer formed on the glass substrate, and a ten-point average roughness R _z on the surface of the transparent layer is 0.5 to 6.0 μm. The glass for touchscreens characterized by this.
(2) a glass substrate, a glass for a touch panel and a transparent layer formed on the glass substrate, an arithmetic mean roughness R _a of the surface of the transparent layer is 0.05~0.20μm The glass for touch panels characterized by this.
(3) The glass for a touch panel according to claim 1 or 2, wherein the transparent layer is a silica film.
(4) On a glass substrate preheated to 40 to 90 ° C., a coating solution containing 0.5 to 7.0% by mass of a silica precursor in terms of SiO ₂ is applied and baked at 100 to 700 ° C. A method for producing glass for a touch panel, wherein a silica film is formed on a substrate.
(5) The manufacturing method of the glass for touchscreens of Claim 4 containing tetraalkoxysilane or its partial hydrolyzate as said silica precursor, and alkoxysilane other than tetraalkoxysilane, or its partial hydrolyzate.

  The glass for a touch panel of the present invention is useful because it has excellent finger slipping properties and has an AG function. In particular, it is useful as a glass for a touch panel using infrared rays, ultrasonic waves, or capacitance.

The glass for a touch panel of the present invention (hereinafter also referred to as “the glass of the present invention”) is a glass for a touch panel having a glass substrate and a transparent layer formed on the glass substrate, and the surface of the transparent layer. the ten-point average roughness of _{R z} is 0.5~6.0μm or arithmetic mean roughness _{R a} of the surface of the transparent layer, is a glass for a touch panel which is 0.05～0.20Myuemu.

  Hereinafter, a preferred example showing the configuration of the glass of the present invention will be described with reference to FIG. 1 which is a schematic cross-sectional view, but the glass of the present invention is not limited thereto.

  As shown in FIG. 1, a touch panel using infrared rays that can be input by contact with a fingertip 15 includes a glass 1 for a touch panel having a glass substrate 5 and a transparent layer 3 formed on the glass substrate 5, a bezel 7. 8, lenses 9 and 10, light emitting diode 11, detection circuits 13 and 14, and phototransistor 17. The infrared light oscillated from the light emitting diode 11 is magnified by the lens 9, passed almost parallel to the surface of the touch panel glass 1, reduced again by the lens 10, and sensed by the phototransistor 17. By blocking the infrared light that is passed substantially parallel to the surface by the fingertip 15, the contact position of the fingertip 15 on the panel is detected using the fact that the infrared light at that portion is not detected by the phototransistor 17. At this time, the position detection accuracy can be increased by the detection circuits 13 and 14. The components of the lenses 9 and 10, the light emitting diode 11, the detection circuits 13 and 14, and the phototransistor 17 are protected by bezels 7 and 8.

  The glass substrate is not particularly limited as long as it is colorless and transparent glass, but for example, colorless and transparent soda lime silicate glass, aluminosilicate glass, lithium aluminosilicate glass, quartz glass, alkali-free glass, other A transparent glass plate made of various glasses can be used. Of these, use of soda lime silicate glass is preferable in terms of film adhesion. The visible light transmittance of the glass substrate is preferably 85% or more from the viewpoint of visibility.

  The plate thickness of the glass substrate is preferably 0.3 to 10.0 mm. When the plate thickness of the glass substrate is within this range, the balance of strength, plate thickness and weight of glass is excellent. Especially preferably, it is 1.1-5.0 mm. The glass substrate is not particularly required to be planar, and a curved or irregular glass substrate may be used as long as the effects of the present invention are achieved.

  As the transparent layer, a low refractive index film having a refractive index of 1.3 to 1.5 is preferably used, and specifically, a silica film is preferably exemplified. The transparent layer is required to have transparency that does not hinder the function of the touch panel. Specifically, the visible light transmittance of the glass substrate on which the transparent layer is formed is preferably 85% or more, particularly 90% or more.

Further, in order to give the transparent layer an antistatic function and an electromagnetic wave shielding function, the transparent layer is made of metal conductive fine particles such as Ag, Ru, an alloy of Ag and Pd, an alloy of Ru and Au, or Sn-doped In ₂ O. ₃ (ITO), oxide conductive fine particles such as Sb-doped SnO ₂ (ATO) can also be contained. In addition, an organic pigment or a dye may be contained for adjusting the transmittance and improving the contrast. Furthermore, a water repellent agent for imparting water repellency, an ultraviolet absorber such as TiO ₂ for preventing deterioration due to ultraviolet rays and infrared rays, an infrared ray absorbent, and a low refractive index material for reducing reflectance are included. You can also. By adding the above-mentioned additives to the coating liquid for forming the transparent layer, functions such as electromagnetic wave shielding can be imparted by coating only one layer without producing and coating another coating liquid, and the production cost can be reduced.

Since the glass for touch panels needs to recognize a contact position correctly, the touch panel glass is required not to slip too much when touched and to be caught, that is, to have finger slipperiness. As a result of intensive studies, the present inventor has found that finger slipperiness is related to the arithmetic average roughness _Ra and the ten-point average roughness _Rz on the surface of the transparent layer, and in particular, to make them within the following ranges. Thus, it has been found that the finger slipperiness as a glass application for a touch panel is excellent. The arithmetic average roughness _Ra and the ten-point average roughness _Rz are values defined by JIS-B0601 (1994). The ten-point average roughness R _z on the surface of the transparent layer of the glass for touch panel of the present invention is 0.5 to 6.0 μm, preferably 0.5 to 2.5 μm, and the arithmetic average roughness _Ra is 0.05. It is -0.20 micrometer, Preferably it is 0.08-0.20 micrometer.

  In order to give the AG function to the surface of the glass for touch panel, it is preferable to give the glass substrate surface gloss. The gloss can be expressed using a 60 ° specular gloss, and can be controlled by adjusting the coating liquid, the preheating temperature of the glass substrate, and the like. The 60 ° specular glossiness means glossiness for light having an incident angle of 60 ° with respect to a line perpendicular to the glass substrate surface, and is preferably 10 to 90%. Outside the above range, the AG function is insufficient. Most preferably, it is 30 to 70%.

When a silica film is formed as the transparent layer, a solution containing a silica precursor is used as the coating solution, and specifically, a solution containing alkoxysilane or a partial hydrolyzate thereof is preferably used. As the alkoxysilane or a partial hydrolyzate thereof, a tetraalkoxysilane represented by Si (OR) ₄ (R is an alkyl group) or a partial hydrolyzate thereof is preferable. Examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, and tetraisopropoxysilane. Examples of the partially hydrolyzed product of alkoxysilane include a low polymer obtained by partial hydrolysis of tetraalkoxysilane and condensation polymerization of 2 to 20 molecules thereof. A typical example of a partial hydrolyzate of tetraalkoxysilane is ethyl silicate 40 (trade name). This ethylsilicate 40 is mainly composed of a tetraethoxysilane low polymer represented by (C ₂ H ₅ O) ₃ Si (OSi (OC ₂ H ₅ ) ₂ ) _n OC ₂ H ₅ (the average value of n is about 5). As a component, the content of SiO ₂ is about 40% by mass.

The concentration of the silica precursor in the coating solution is 0.5 to 7.0% by mass in terms of SiO ₂ in that the surface roughness of the transparent film can be controlled to an appropriate value by an appropriate application time. preferable.

  As the solvent for the coating solution, an organic solvent is preferably used, and specifically, an organic solvent having a boiling point of 120 ° C. or less is preferably used. Examples of the organic solvent include alcohols such as methanol, ethanol and isopropyl alcohol, carboxylic acid esters such as methyl acetate and ethyl acetate, and ketones such as acetone and methyl ethyl ketone. In addition, two or more kinds may be used in combination.

  Further, a medium boiling solvent having a boiling point of 120 to 180 ° C. or a high boiling solvent having a boiling point exceeding 180 ° C. may be added to the organic solvent. By adding the medium-boiling point solvent or the high-boiling point solvent, it becomes possible to form a transparent layer having excellent finger slipping properties and an AG function. The addition amount of the medium boiling point solvent is preferably 0.1 to 50% by mass in the coating solution, and the addition amount of the high boiling point solvent is preferably 0.1 to 30% by mass in the coating solution. If the addition amount of the medium-boiling point solvent and the low-boiling point solvent is too small, the finger slipping property is insufficient, and if it is too large, it is difficult to impart an effective AG function. Examples of the medium boiling point solvent include diacetone alcohol, and examples of the high boiling point solvent include ethylene glycol and propylene alcohol.

When tetraalkoxysilane or a partial hydrolyzate thereof is contained in the coating solution, the coating solution further contains an alkoxysilane other than tetraalkoxysilane (“alkoxysilane other than tetraalkoxysilane”) as a silica precursor. Is hereinafter referred to as “other alkoxysilane”) or a partial hydrolyzate thereof. Examples of other _{alkoxysilanes, X n Si (OR) 4} -n is a (n = 1~3, R is an alkyl group, X 1 monovalent group other than alkoxy groups.) And dimer (RO _{) 3-m X m Si-} Y-SiX m (OR) 3-m (m = 0~2, R is an alkyl group, Y is a divalent group (provided that both bonds terminal atoms are not oxygen.).) The compound shown by these is illustrated.

  Here, as monovalent group X, vinyl group, styryl group, epoxy group-containing group (3-glycidoxypropyl group, 2- (3,4-epoxycyclohexyl) ethyl group, etc.), methacryloyloxy group-containing group ( 3-methacryloxypropyl group, etc.), acryloxy group-containing group (3-acryloxypropyl group, etc.), ureido group-containing group (3-ureidopropyl group, etc.), mercapto group-containing group (3-mercaptopropyl group, etc.), sulfide Group-containing groups (such as bis (triethoxysilylpropyl) tetrasulfide), isocyanate group-containing groups (such as 3-isocyanatopropyl group), alkoxysilyl group-containing groups (such as trimethoxysilylhexyl group), alkyl groups (methyl group, ethyl group) Group) and aryl groups (phenyl group and the like).

  The divalent group Y includes a polymethylene group (ethylene group, trimethylene group, hexamethylene group, etc.), a halogenated polymethylene group obtained by substituting the hydrogen of the polymethylene group with a halogen, or a divalent group obtained by removing the hydrogen of the monovalent group X. Are exemplified.

Concentration of other alkoxysilane in the coating solution is preferably 0.01 to 0.5 wt% in terms of SiO _2. If it is less than 0.01% by mass, it is difficult to obtain appropriate finger slipping properties, and if it exceeds 0.5% by mass, the abrasion resistance of the coating film may be insufficient.

  A resin component may be included in the coating solution. The resin component means a polymer compound containing an organic compound as a main component, and specifically an acrylic resin is exemplified. By including a resin component in the coating solution, finger slipping is improved, but the mechanism is not clear. However, the rate at which the solvent in the coating solution evaporates can be adjusted by containing the resin component, and as a result, it is assumed that the finger slipping property is expressed by the interaction between the silica particles contained in the coating solution and the resin component. is doing. When an acrylic resin is used as the resin component, it is particularly preferable to use 3-glycidyloxypropyltrimethoxysilane as the other alkoxysilane from the viewpoint of the wear resistance and finger slipping property of the coating film.

Specifically, as the coating solution, ethylene glycol is 1 to 20% by mass, preferably 3 to 15% by mass, ethanol is 50 to 90% by mass, isopropyl alcohol is 5 to 40% by mass, and other methanol or methyl ethyl ketone is used. Tetraethoxysilane or a hydrolyzate thereof is 0.0028 to 0.1 mol in terms of SiO ₂ and 1.6-bistrimethoxysilylhexane is 0.001 to 0.03 mol with respect to 100 ml of the mixed solvent mixed in a small proportion. A coating solution containing water in a catalytic amount of 12 to 24 times mol of tetraethoxysilane or a hydrolyzate thereof, hydrochloric acid, sulfuric acid, nitric acid and the like has an appropriate AG function, adhesion between the glass and the transparent layer, and It is preferably exemplified in terms of finger slipperiness. If the content ratio of SiO ₂ is within this range, it is preferable in that the formation time of the transparent layer can be shortened and the AG function of the transparent layer is excellent. Further, if the content of water is within this range, the arithmetic mean roughness R _a of the surface of the transparent layer formed preferably because it can range from 0.05~0.20μm described above.

  A preferred method for forming the transparent layer is as follows. The glass substrate is preheated to be in the range of 40 to 90 ° C., and the coating solution is sprayed onto the surface of the glass substrate by spraying, and after coating, 100 to 700 ° C., preferably 250 to 350 ° C., 5 to 60 minutes. Preferably, the baking is performed in the air for 15 to 30 minutes. If the preheating temperature of the glass substrate is within the above range, the applied coating solution is in an appropriate wet state on the glass substrate surface, so that a transparent layer having an AG function can be formed, and a glass substrate formed after heating and firing, It is preferable at the point from which adhesiveness with a transparent layer becomes favorable. Moreover, if the temperature and heating time for heating and baking are within this range, the adhesion between the glass substrate and the transparent layer will be good, and the resulting glass for touch panels of the present invention will have practically sufficient wear resistance. To preferred.

  The glass for a touch panel of the present invention can be used as it is a glass substrate on which a transparent layer is formed by the above-described production method, or can be used by cutting, chamfering and chamfering a glass substrate on which a transparent layer is formed as necessary. it can. The glass substrate before forming the transparent layer may be cut and chamfered, and then the transparent layer may be formed.

The glass for a touch panel of the present invention is useful because it has excellent abrasion resistance, excellent finger slipperiness, and has an AG function. This is excellent in wear resistance because it is not made porous, and has a ten-point average roughness R _z or arithmetic average roughness _Ra in the above-mentioned range, and thus has good finger slipperiness with respect to the touch panel. That is, it is considered that the fingertip does not slide too much and is not caught, and the gloss is in the above-described range and the surface is not glaring.

  Since the glass for touch panel of the present invention uses a glass substrate, it is excellent in durability, heat resistance and chemical resistance compared to plastics and resin films, etc., and is not affected by temperature in the use environment, and is alcohol-cleaned. Has the advantage of being possible. In particular, the glass for a touch panel of the present invention is useful as a glass for a touch panel using infrared rays, ultrasonic waves, or capacitance.

  Below, an Example (Example 1) and a comparative example (Examples 2-4) are mentioned, and the glass for touchscreens of this invention is demonstrated in detail. However, the present invention is not limited to this.

(Coating solution adjustment)
Tetraethoxysilane (trade name: Ethyl silicate 40, manufactured by Tama Chemical Industry Co., Ltd.) with respect to a mixed solvent of 1 g of methanol, 68.3 g of ethanol, 1 g of methyl ethyl ketone, 8 g of isopropyl alcohol, 7 g of ethylene glycol, 7 g of water and 1.1 g of 61% nitric acid. ) And 6 g of 1,6-bistrimethoxysilylhexane were mixed and stirred to obtain a coating solution. The silica content in the coating solution was 2.6% by mass in terms of SiO ₂ (1,6-bistrimethoxysilylhexane-derived silica content was 0.2% by mass).

(Example 1)
After applying 50 ml of coating solution by spraying onto the surface of a glass substrate made of soda lime silicate glass (area: 0.1 m ² , thickness: 2.7 mm) preheated to a surface temperature of 70 ° C., A silica film (refractive index = 1.4) was formed by heating and baking in the atmosphere at 300 ° C. for 30 minutes, and a glass for a touch panel was obtained.

(Example 2)
A glass for a touch panel was obtained in the same manner as in Example 1 except that the glass substrate was preheated to a surface temperature of 95 ° C.

(Example 3)
A glass for a touch panel was obtained in the same manner as in Example 1 except that the glass substrate was preheated to a surface temperature of 35 ° C.

(Example 4)
The glass substrate itself was used as the glass for the touch panel.

The surface roughness (arithmetic average roughness _Ra and ten-point average roughness R _z ), finger slipperiness, 60 ° specular gloss, and visible light transmittance of the obtained glass for touch panel and glass substrate were measured and evaluated. . The results are shown in Table 1. The surface roughness, finger slipperiness, 60 ° specular gloss, and visible light transmittance were measured by the following methods.

(Surface roughness)
The surface roughness (arithmetic average roughness _Ra and ten-point average roughness _Rz ) was measured by the method described in JIS-B0601 (1994). The surface roughness is measured using a surface roughness measuring machine (Surfcom 1400D: manufactured by Tokyo Seimitsu Co., Ltd.), scan length = 5.0 mm, cut-off value = 0.8 mm, stylus = 5 μmR, 4 mN. Below, it measured at arbitrary four measurement points, and calculated the average.

(Finger slipperiness)
Finger slipping was evaluated by performing the following sensory test. That is, the surface of the glass for a touch panel in each of Examples 1 to 4 was lightly slid with a dry index finger, and it was evaluated on a five-point scale (1 to 5 points) whether it was possible to move without slipping and without being caught. . Evaluation was evaluated as ◯ when the average value of 10 subjects was 3.5 or more, △ when it was 1.5 or more and less than 3.5, and × when it was less than 1.5.

(60 ° specular gloss)
Using a method described in JIS-Z8741 (1997), using a specular gloss measuring machine (digital variable gloss meter UGV-5K and SM color computer SM-5, both manufactured by Suga Test Instruments Co., Ltd.), a glass substrate A black paint was applied to the back surface of the sample, and antireflection treatment was performed on the back surface, and the 60 ° specular gloss at the center point of the sample was measured.

(Visible light transmittance)
The visible light transmittance at the center of the sample was measured using a spectrophotometer (UV-3100PC, manufactured by Shimadzu Corporation) by the method described in JIS-R3106 (1998).

From the results shown in Table 1, it can be seen that the finger slipperiness is a good value by setting the arithmetic average roughness _Ra and the ten-point average roughness _Rz within appropriate ranges. Moreover, it can be seen that the glass for touch panel of the present invention has a sufficient AG function because the 60 ° specular gloss is in an appropriate range, has a high visible light transmittance, and is excellent in transparency.

  The glass for a touch panel of the present invention is excellent in transparency and finger slipping property, has an AG function, and is particularly useful as a glass for a touch panel using infrared rays, ultrasonic waves, or capacitance.

The schematic sectional drawing which shows an example of a touch-panel apparatus.

Explanation of symbols

1: Glass for touch panel 3: Transparent layer 5: Glass substrate 7, 8: Bezel 9, 10: Lens 11: Light emitting diode 13, 14: Detection circuit 15: Fingertip 17: Phototransistor

Claims (5)

A glass for a touch panel having a glass substrate and a transparent layer formed on the glass substrate, wherein the ten-point average roughness R _z on the surface of the transparent layer is 0.5 to 6.0 μm. Glass for touch panels. And the glass substrate, a glass for a touch panel and a transparent layer formed on the glass substrate, and an arithmetic average roughness R _a of the surface of the transparent layer is 0.05~0.20μm Touch panel glass.   The glass for a touch panel according to claim 1 or 2, wherein the transparent layer is a silica film. A glass substrate preheated to 40 to 90 ° C. is coated with a coating solution containing 0.5 to 7.0% by mass of a silica precursor in terms of SiO ₂ and baked at 100 to 700 ° C. A method for producing glass for a touch panel, comprising forming a silica film. The manufacturing method of the glass for touchscreens of Claim 4 which contains tetraalkoxysilane or its partial hydrolyzate as said silica precursor, and alkoxysilane other than tetraalkoxysilane, or its partial hydrolyzate.

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