JPH0465384B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a display device having a specular reflection reducing effect and an antistatic effect, and a method for manufacturing the same. [Prior Art] A method of applying a specular reflection reducing effect and an antistatic effect to a display device such as a cathode ray tube or a liquid crystal display involves heating a front panel made of glass or plastic in advance, and then applying a material such as a partially hydrolyzed silicate ester. Spraying a colloidal solution of a silicon compound, a reactive silicon compound solution such as silicon tetrachloride, or a solution in which a water-soluble compound of an inorganic metal such as platinum, gold, palladium, or tin is mixed with the solution,
There was a manufacturing method in which a fine uneven coating of silicon oxide or hydrate was formed on the front plate, and then this fine uneven coating was baked onto the front plate. (Unexamined Japanese Patent Publication 1986)
There was also a method of forming a coating layer on a cathode ray tube by vacuum evaporation or a dip method, in which tin oxide or indium oxide and silicon oxide were mixed or laminated. (Utility Model Publication No. 59-168951) However, in the display devices obtained by these methods, the regular reflection reduction effect (hereinafter referred to as non-glare) is insufficient, and the antistatic effect is affected by the surrounding atmosphere. (Temperature and humidity) and the applied coating lowered the resolution. Furthermore, the formed uneven coating has poor adhesion and peels off easily, has low mechanical strength and is easily damaged, and has no durability such as acid resistance, alkali resistance, salt water resistance, water resistance, etc., so it may peel off or elute. The non-glare and antistatic effects were reduced. [Problems to be Solved by the Invention] The present invention attempts to solve the above-mentioned problems associated with the prior art. It is an object of the present invention to provide a display device on which a finely textured film is formed that has a non-glare and antistatic effect and is excellent in durability, adhesion, and mechanical strength, and a method for manufacturing the same. [Means for Solving the Problems] The present invention provides: (1) In a display device in which a transparent conductive film is formed on the surface of a front plate, the transparent conductive film is made of zirconium oxide, silicon oxide, and a conductive material. The front plate made of tin oxide and on which the transparent conductive film is formed has a gloss level of 30%≦gloss≦90% and a resolution of ≧50 lines/
cm, 10 ⁴ Ω/□≦Surface resistance≦10 ⁹ Ω/□, (2) Zirconium oxysalt, non-precipitating silica, and conductive tin oxide colloidal particles interact with water to prevent growth. A display device characterized in that a transparent conductive coating liquid composition uniformly dispersed in an agent and a diluent is applied by a spray method to a front plate heated and held at 40 to 90°C, and then dried and/or baked. (3) A transparent conductive coating liquid composition in which a zirconium oxysalt, non-precipitating silica, and conductive tin oxide colloidal particles are uniformly dispersed in water, a growth inhibitor, and a diluent is prepared in advance by 40°C. It is characterized by applying a spray method to the front panel heated and maintained at ~90°C, then drying and/or baking, and then applying a transparent protective coating composition thereon by a spray method, followed by drying and/or baking. A method for manufacturing a display device. It is. The display device and the manufacturing method thereof according to the present invention will be specifically explained below. The specular reflection reducing effect (non-glare) of a coating depends on the reflectance of the coating. The reflectance of a coating is determined by its refractive index and its surface shape, which in turn depends on the material that makes up the coating and the density of the coating. Therefore, in order to lower the reflectance, it is necessary to use only a substance with a small refractive index, or to form a coating by mixing a substance with a large refractive index with a substance with a small refractive index, or to form a coating with a substance with a large refractive index. It is sufficient to form a film and further laminate a film made of a substance with a small refractive index, or to lower the density of the film. Next, regarding the shape of the coating surface, the higher the smoothness, the higher the reflectance, so it is better to reduce the smoothness.
If the smoothness decreases too much, the resolution of the film will also decrease at the same time. Therefore, in the present invention, conductive tin oxide colloidal particles (refractive index
2.1) can be sprayed to form a finely uneven coating, thereby lowering the refractive index of the coating itself, or by laminating a silica or plastic coating (refractive index 1.4 to 1.7) on top of the coating. Alternatively, silica or plastic is infiltrated into some of the pores of the coating. In this way, the apparent refractive index of the coating is lowered, and the surface of the coating is made uneven to the extent that the resolution is not significantly reduced, thereby making the coating non-glare. However, in general, when a coating becomes porous, its surface area increases compared to a smooth coating, resulting in poor durability; however, in the present invention, this problem has been solved by using highly durable zirconia. As mentioned above, the present invention employs zircoium oxide, silicon oxide, and conductive tin oxide as the constituent materials of the transparent conductive coating, thereby achieving non-glare and antistatic effects and excellent durability, adhesion, and mechanical strength. It became possible to obtain display devices. There are various methods for obtaining such a display device, including a transparent conductive coating liquid composition containing a zirconia compound as a zirconium oxide source, a silica compound as a silicon oxide source, and conductive tin oxide colloidal particles. The object of the present invention can be achieved by spraying on the front plate. Any transparent conductive coating liquid composition comprising the above-mentioned constituents can be used in the present invention; however, zirconium oxysalt, non-precipitating silica, and conductive tin oxide colloidal particles are combined with water, a growth inhibitor, and a diluent. If a transparent conductive coating liquid composition uniformly dispersed in the agent is used, an even better transparent conductive film can be obtained. First, the first transparent conductive coating liquid composition will be explained. The zirconia coating formed by the coating method generally uses zirconium alkoxide. However, since zirconium alkoxide has a fast hydrolysis rate, it is difficult to control the rate, and when it is applied as a coating liquid to a transparent substrate, it is easily affected by humidity, and the properties of the film are influenced by it. It is difficult to continuously obtain a coating with properties. Furthermore, since the zirconium alkoxide undergoes hydrolysis in the presence of a trace amount of moisture, the coating solution cannot be stored for a long period of time. Furthermore, zirconium alkoxide is expensive and is not suitable as a raw material for industrial products. In the present invention, the above problem was solved by using a zirconium oxysalt as a zirconia source.
The zirconium oxysalt used in this transparent conductive coating composition is particularly preferably zirconium oxychloride or zirconium oxynitrate, but is not limited thereto. Even when a zirconium oxy salt is applied in the form of an aqueous solution to a base material such as glass, the aqueous solution is repelled and the coating becomes white. This occurs because the film-forming property of the zirconium oxysalt is low and the surface tension of the aqueous solution is high with respect to the base material. First, non-precipitating silica was added to improve the film-forming property. In order to further lower the surface tension, it is necessary to mix an organic solvent with a low surface tension, or to remove part of the water from the system after mixing. However, with common organic solvents, when the water content becomes low, the zirconium oxysalt, non-precipitated silica, and conductive tin oxide colloidal particles become unstable and may decompose, causing gelation or promoting polymerization. Therefore, in the transparent conductive coating liquid composition, hydrolysis of the above-mentioned zirconium oxysalt, non-precipitating silica and conductive tin oxide colloidal particles, among various organic solvents,
A specific organic solvent that prevents gelation, etc. (hereinafter referred to as a growth inhibitor) is mixed into a mixed solution of zirconium oxysalt, non-precipitating silica, and conductive tin oxide colloidal particles, or mixed with water after mixing. Part of the water is dehydrated from within the system. The transparent conductive coating liquid composition prepared in this way is stable even when the water content is reduced without causing gelation of the zirconium oxysalt and non-precipitating silica, and at the same time improves film-forming properties and is transparent and conductive. The surface tension of the coating liquid composition can be lowered. Therefore, when diluted with a diluent and applied to a substrate, even if the diluent, water and some of the growth inhibitor evaporate, the remaining growth inhibitor will prevent the polymerization of the zirconium oxysalt and non-precipitating silica. This occurs and a film is formed. The non-precipitating silica used in this transparent conductive coating liquid composition is obtained by exchanging alkali and hydrogen in an aqueous alkali silicate solution by an ion exchange method or a dialysis method, and is 2.0wt. %
(SiO ₂ equivalent) When the aqueous solution is centrifuged at 250,000 G for 1 hour, the amount of sediment is 30 parts by weight or less, preferably 10 parts by weight or less, based on the total SiO ₂ in the aqueous solution. Preferably, the non-precipitating silica obtained by the invention of ``Non-precipitating silica composition for coating and method for producing the same'' (Japanese Patent Application No. 187835/1983) previously filed by the present applicant is used. The non-precipitating silica obtained in this manner is inherently unstable and tends to form colloidal particles or gel, but is stabilized by the growth inhibitor in the transparent conductive coating composition. Furthermore, this non-precipitating silica does not gel itself even when mixed with a zirconium oxy salt, nor does it cause a zirconium oxy salt to gel. The conductive tin oxide colloidal particles according to this transparent conductive coating composition are colloidal particles in which tin oxide, tin oxide doped with a different element, or both are dispersed in water or an organic solvent,
This is based on "Tin oxide sol and method for producing the same" (Japanese Patent Application No. 75283/1983, filed by the present applicant).
These are electrically conductive tin oxide colloidal particles obtained by the invention of Publication No. 230617). The average particle size of the colloidal particles is preferably in the range of 0.01 to 0.1 μm. If it is less than 0.01μm, the film cannot be made porous,
If it exceeds 0.1 μm, the total light transmittance and resolution of the resulting coating will decrease, impairing the transparency of the substrate. However, even if the average particle size is 0.1 μm or less, if a large number of particles exceeding 0.1 μm are included, the total light transmittance and resolution of the coating will decrease, reducing the transparency of the base material. It is preferable that 60% or more of the particles are particles with a particle size of 0.1 μm or less. The growth inhibitor used in this transparent conductive coating liquid composition is one that does not cause gelling or promote polymerization of the zirconium oxysalt, non-precipitating silica, and conductive tin oxide colloid particles, and is preferably N- Methyl-2-pyrrolidone, N,N dimethylformamide, morpholine, ethylene glycol monomethyl ether, ethylene glycol noethyl ether, ethylene glycol, etc., and their derivatives are used singly or in combination of two or more. The diluent for this transparent conductive coating liquid composition is
zirconium oxysalts, non-precipitating silica and conductive tin oxide colloidal particles that do not gel;
Or something that does not promote polymerization, such as methanol, ethanol, n-propanol, i-
Alcohols such as propanol, n-butanol, i-butanol, and t-butanol, ethers such as methyl acetate, ethyl acetate, and diethyl ether, and acetone can be used alone or in combination of two or more. The composition ratio of ZrO ₂ , SiO ₂ , conductive tin oxide colloidal particles, moisture, growth inhibitor, and diluent is as follows: First, the growth inhibitor must be 1≦( in the total molar ratio of ZrO ₂ and SiO ₂ growth inhibitor)/(ZrO ₂ +SiO ₂ )≦25. Preferably the number is 2 or more. If it is less than 1, gelation of the transparent conductive coating composition tends to occur, shortening the pot life (usable period) and making it impossible to store it for a long time. If it exceeds 25, when the transparent conductive coating composition is applied and cured, the curing becomes uneven and the durability of the coating deteriorates. Second, water has a weight ratio of 0.1≦H ₂ O/ZrO _{2 .}
After satisfying the condition that ZrO ₂ ≦40, it is preferably 50 wt% or less based on the total weight of the transparent conductive coating liquid composition (hereinafter referred to as the total weight). If it is less than 0.1, gelation of the zirconium oxysalt will occur, and if the weight ratio exceeds 40 or 50 wt% of the total weight, the growth inhibitor will not harden and the transparent conductive coating composition will be repelled on the transparent substrate. This is because Thirdly, the total weight of ZrO ₂ , SiO ₂ , and conductive tin oxide colloidal particles is preferably 0.1 to 20 wt% based on the total weight, and 0.1 to 10 wt% for long-term storage of the transparent conductive coating composition. % is good. If it exceeds 20 wt%, gelation of the transparent conductive coating composition tends to occur.
Fourth, the ratio of conductive tin oxide colloidal particles, zirconium oxysalt, and non-precipitating silica is 1≦
(Conductive tin oxide colloidal particles)/(ZrO ₂ +SiO ₂ )
≦5 (weight ratio) is good. If it is less than 1, the conductivity of the film will be poor or the film will not be porous, and if it exceeds 5, the adhesion of the film will be reduced. Fifth, the ratio of non-precipitating silica to zirconium oxysalt is preferably 0.05≦SiO ₂ /ZrO ₂ ≦1 (weight ratio).
If it is less than 0.05, the adhesion of the film will be poor, and if it exceeds 1, the durability of the film will be poor. In this way, a transparent conductive coating liquid composition is obtained. Second, the transparent protective coating liquid composition will be explained. This transparent protective coating liquid composition is described in the above-mentioned "Non-precipitating silica composition for coating and method for producing the same"
A non-precipitating silica composition for coating obtained by the invention disclosed in Japanese Patent Application No. 61-187835 and Japanese Unexamined Patent Publication No. 63-43965 can be used. It is also possible to use a coating solution prepared by adding water and a mineral acid such as hydrochloric acid or nitric acid, or a carboxylic acid such as acetic acid to silicon alkoxide and diluting it with a diluent such as alcohol, which results in a more transparent and hard coating. It is also possible to use a paint prepared by dispersing or diluting silicone resin, melamine resin, or urethane resin. Furthermore, the present applicant has previously applied for a "coating liquid composition" (Japanese Patent Application No. 61-288922;
14206) or "Coating liquid for forming transparent film"
(Japanese Patent Application No. 61-291935 and Japanese Unexamined Patent Publication No. 63-145370) can also be used. Next, a method for manufacturing a display device according to the present invention will be explained. A preferred first manufacturing method of the present invention is to preheat and
One layer or multiple layers of the transparent conductive coating composition are applied to the held front plate by a spray method. The front plate is heated and maintained at a temperature of 40 to 90°C, more preferably 50 to 70°C. If the temperature is below 40°C, when the droplets are applied to the front panel, the liquid components will not dry sufficiently and leveling will occur, making it impossible to obtain a non-glare film.If the temperature exceeds 90°C, the liquid components will dry rapidly and the film will not form. This is because the adhesion, transparency, and durability of the film deteriorate. Therefore, when applying a transparent conductive coating liquid composition by a spray method, the amount of coating liquid, coating speed, and air pressure supplied to the spray must be adjusted so that the front plate does not deviate from this temperature. The display device of the present invention is then obtained by drying, but if a coating with even higher durability and mechanical strength is required, it may be fired at a temperature of 300° C. or higher and lower than the glass transition point of the front plate. At this time, the firing process may be repeated many times as long as the temperature is below the glass transition point. In the second manufacturing method, the transparent protective coating liquid composition is applied onto the film obtained by the first manufacturing method by a spray method in the same manner as described above. however,
When using a non-precipitating silica composition for coating or a silicon alkoxide coating liquid, it may be spray coated onto the dried coating in the first production method, and then baked. The shape of the finely uneven coating surface conforms to Japanese Industrial Standards.
The ten-point average roughness (hereinafter referred to as _RZ ) according to JISBO601-82 is preferably 0.2 to 5 μm, preferably 0.2 to 3 μm. When it is less than 0.2 μm, transparency such as resolution is good, but non-glare is reduced and antistatic effect cannot be obtained. If it exceeds 5 μm, transparency such as resolution will deteriorate. The display device of the present invention can be obtained by the manufacturing method described above. The resulting display device has a resolution of 50 lines/cm or more, a gloss level of 30-90%, and a surface resistance of 10 ⁴ Ω/□~
10 ⁹ Ω/□. If the resolution is less than 50 lines/cm or the gloss is less than 30%, the transparency of the front plate will deteriorate, and if the gloss exceeds 90%, the coating will not be glare-free and the surface resistance will be less than 10 ⁹ Ω/□. If it exceeds the limit, the antistatic effect cannot be obtained. For the front plate according to the present invention, transparent substrates such as flat glass and plastic, curved glass and plastic can be used. The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples. [Example] Example 1 316 g of potassium stannate and 384 g of tartarite were added to 686 g of water.
A raw material solution was prepared by dissolving it in g. The above raw material solution was added over 12 hours together with nitric acid to 1000 g of water heated to 50° C. and stirred, and the system was hydrolyzed while maintaining the pH at 8.5 to obtain a sol. Colloidal particles were filtered from this sol, washed to remove by-product salts, and then dried, calcined in air at 350℃ for 3 hours, and further calcined in air at 650℃ for 2 hours to obtain a fine powder. Ta. 400 g of the obtained powder was added to 1600 g of an aqueous potassium hydroxide solution (containing 40 g of KOH), and the mixture was stirred in a sand mill for 3 hours while maintaining the mixture at 30° C. to obtain a conductive tin oxide colloid (conductive sol). Next, this conductive tin oxide colloid was treated with an ion exchange resin to obtain a dealkalized conductive tin oxide colloid. This dealkalized conductive tin oxide colloid contained no precipitates, had a solid content concentration of 20 wt%, and had an average particle size of 0.07 μm. The amount of particles of 0.1 μm or less was 87% of the total particles. As _SiO2
5wt% sodium silicate (SiO ₂ /Na ₂ O = 3mol/
mol) was passed through a hydrogen-type ion exchange resin column at a space velocity of SV=5 while maintaining the temperature at 15°C (non-sedimentable silica liquid). 50g of the non-precipitating silica liquid and 50g of the conductive sol obtained in this way.
50g and 20g of N-methyl-2-pyrrolidone.
10g of 25wt% zirconium oxychloride aqueous solution in terms of ZrO ₂ and MeOH/BuOH (weight ratio 1/1)
170 g was added and thoroughly mixed to obtain a transparent conductive coating liquid composition. A 14-inch cathode ray tube panel maintained at 60℃ was sprayed with a spray air pressure of 1.5Kg/ ^cm2 .
Spray applied at ml/min. Thereafter, it was dried at 110°C for 10 minutes and fired at 450°C for 30 minutes. In addition, the average particle diameter of the conductive tin oxide colloidal particles and
The proportion of particles with a particle diameter of 0.1 μm or less was determined using an ultracentrifugal particle size analyzer (manufactured by Horiba, trade name: CAPA-500), adjusting the solid content concentration in the measurement sample to 0.5 wt%, and heating at 5000 r.pm. It was measured with Example 2 The same procedure as Example 1 was carried out except that the 14-inch cathode ray tube panel was maintained at 70°C. Example 3 An acrylic plate was used and dried at 110°C for 30 minutes.
I didn't fire it. The rest was the same as in Example 1. Example 4 The transparent conductive coating liquid composition of Example 1 was spray-coated and the panel dried at 110°C for 30 minutes was maintained at 60°C, and 100 g of Ethyl Silicate 28 (manufactured by Tama Chemical) was applied.
A transparent protective coating liquid composition, which was a uniform mixture of 749 g of i-propanol, 84 g of water, and 0.5 g of 35 wt% hydrochloric acid, was spray applied at a spray supply air pressure of 0.5 Kg/cm ² at a rate of 20 ml/min. Then dry at 110℃10, then 450℃
Bake for 30 minutes. Example 5 N-
After adding 43 g of methyl-2-pyrrolidone and uniformly mixing, the mixture was heated to 80° C. using a rotary evaporator to distill out 93 g of water. This liquid was cooled and 120 g of ethanol was sufficiently dispersed to obtain a transparent protective coating liquid composition. The panel obtained in Example 1 was maintained at 60° C. and the above transparent protective coating liquid composition was applied at a rate of 20 ml/min with a spray supply air pressure of 1.5 Kg/cm ² . Thereafter, it was dried at 110°C for 10 minutes and fired at 250°C for 30 minutes. Example 6 157 g of methyl ethyl ketone was added to 10 g of 50 wt % silicone resin (manufactured by Kanebuchi Chemical Co., Ltd., trade name: Semlac, xylene diluted product) and mixed uniformly to obtain a transparent protective coating liquid composition. The panel obtained in Example 1 was maintained at 60° C. and the transparent protective coating composition described above was applied at a rate of 20 ml/min with a spray supply air pressure of 15 kg/cm ² . Then 110℃
Dry for 10 minutes. Comparative Example 1 The same procedure as Example 1 was carried out except that the 14-inch cathode ray tube panel was maintained at 30°C. Comparative Example 2 The same procedure as Example 1 was carried out except that the 14-inch cathode ray tube panel was maintained at 110°C. Comparative Example 3 100 g of non-precipitating silica liquid obtained in Example 1, 50 g of conductive sol, and 25 g of N-methyl-2-pyrrolidone
Example 1 except that a transparent conductive coating liquid composition obtained by adding g and 125 g of EtOH and thoroughly mixing them was used.
I did the same thing. (No zirconium oxysalt was used.) Comparative Example 4 Example 1 for making a transparent conductive coating composition
100g of the non-precipitating silica liquid and 100g of the conductive sol obtained in
When 380 g of MeOH/EtOH (weight ratio 1/1) was sufficiently dispersed, the mixture turned into a gel after 30 minutes. (No growth inhibitor was used) Comparative Example 5 A glass plate (200 x 200 x 3 mm) was immersed in the transparent conductive coating composition obtained in Example 1 and pulled up at a speed of 5 cm/min. Then dry at 110℃ for 30 minutes, then dry at 450℃ for 30 minutes.
Bake for a minute. The following evaluations were performed on these Examples and Comparative Examples. Glossiness: Glossiness (G) was evaluated at a measurement angle of 60°C according to the glossiness measurement method of JISK7105-81. Resolution: Attach the birch layer shown in Figure 1 to the back of the panel or acrylic board (side without coating),
The separation of the bars was expressed as the maximum number of bars per cm when the separation of the bars could be observed when set in the apparatus shown in FIG. Surface resistance: Evaluated using Hirester (manufactured by Mitsubishi Yuka Co., Ltd.) at a measurement voltage of 500V. Adhesion: A part of commercially available cellophane tape with a width of 12 mm was pasted on the film, the rest was held perpendicular to the film, and it was instantly peeled off, and the presence or absence of the film was visually observed. Membrane strength: Fix the panel or acrylic board on the scale and use an office eraser (LION No. 50-
50) was placed on the coating, a load of 2 kg was applied, and the number of reciprocations at which the surface of the panel or acrylic board was exposed was evaluated. Durability: After soaking in the solution below, it was evaluated in terms of gloss (same as), surface resistance (same as), and adhesion (same as). (1) 1 week in 15wt% ammonia water at room temperature. (2) 1 week in 10wt% NaCl aqueous solution at room temperature. (3) Place in boiling water for 30 minutes. (4) 1 week at room temperature in 50wt% acetic acid aqueous solution. (5) 1 week in acetone at room temperature. (6) 1 week in ethanol at room temperature. (7) in i-propanol for 1 week at room temperature. R _Z : In the JISBO601-82 R _Z measurement method,
It was measured using a stylus-type film pressure meter (manufactured by Rank Taylor Hobson, trade name: Talystep).

[Table]

【table】

[Table] [Effects of the Invention] The present invention provides a specific transparent conductive coating liquid composition,
After spraying to form a finely textured film on a glass or other front plate that has been heated and maintained in advance,
By drying and/or baking, when used as a front plate for surface devices such as cathode ray tube panels and liquid crystal display panels, it has a non-glare and antistatic effect without reducing the resolution of the front plate. A display device having a finely textured coating with excellent durability, adhesion, and mechanical strength can be obtained.

[Brief explanation of drawings]

FIG. 1 shows a birch court, and FIG. 2 shows a resolution measuring device. 1: bar, 2: 〓, where a (width of bar) = b
(width between 〓). Chart is every 5 pieces/cm (10, 15,
20, 25, etc.). 3: Panel or acrylic board, 4: Birchat, 5: 20W fluorescent light, 6:
Case with white interior.

Claims (1)

[Scope of Claims] 1. In a display device in which a transparent conductive film is formed on the surface of a front plate, the transparent conductive film is made of zirconium oxide, silicon oxide, and conductive tin oxide, and the transparent conductive film The front plate formed with 30%≦gloss≦90%, resolution≧50 lines/cm,
A display device characterized in that 10 ⁴ Ω/□≦surface resistance≦10 ⁹ Ω/□. 2. A transparent conductive coating liquid composition in which zirconium oxysalt, non-precipitating silica, and conductive tin oxide colloidal particles were uniformly dispersed in water, a growth inhibitor, and a diluent was heated and maintained at 40 to 90 °C in advance. A method for manufacturing a display device, characterized in that the front panel is coated by a spray method, and then dried and/or baked. 3. A transparent conductive coating liquid composition in which zirconium oxysalt, non-precipitating silica, and conductive tin oxide colloidal particles were uniformly dispersed in water, a growth inhibitor, and a diluent was heated and maintained at 40 to 90 °C in advance. 1. A method for manufacturing a display device, which comprises applying a transparent protective coating composition to a front panel by a spray method, followed by drying and/or baking, and then applying a transparent protective coating composition thereon by a spray method, followed by drying and/or baking. 4. The method for manufacturing a display device according to claim 3, wherein the transparent protective coating liquid composition is one in which silicon alkoxide is uniformly dispersed in water, an acid, and a diluent. 5. The method for manufacturing a display device according to claim 3, wherein the transparent protective coating composition is a composition in which non-sedimentable silica is uniformly dispersed in water, a growth inhibitor, and a diluent. 6. The method for manufacturing a display device according to claim 3, wherein the transparent protective coating liquid composition is one in which a binder resin is uniformly dispersed in a diluent.