JP2003021705A - Optical film sheet and method for manufacturing display device by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of a display irregularity in four corners when a plastic material is used for a substrate. SOLUTION: The optical film sheet has a barrier layer which can be removed at a time of forming electrodes on one surface of a plastic film sheet and has a single layer or a composite layer having <=0.1 g/m<2> / day permeability of water vapor on the other surface. A display device is manufactured by using the above sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical film sheet that can be used as a substrate of a liquid crystal display device and the like, and a method of manufacturing a display device using the same.

[0002]

2. Description of the Related Art A glass substrate has been conventionally used as a display device substrate. However, due to the rapid growth of portable display media in recent years, research and development of display media using a plastic substrate, which is light and does not break, have been conducted. However, plastic has gas permeability such as oxygen and water vapor, and dimensional change rate due to water absorption,
When plastic is used for the substrate, display defects may occur due to bubbles generated by the permeated gas, or display defects may occur due to a decrease in the specific resistance of the liquid crystal due to the inclusion of water in the liquid crystal. However, there was a problem that the connection failure occurred due to the displacement of the transparent electrode circuits on the upper and lower substrates due to the dimensional change due to moisture absorption. In order to solve this problem, a film having a high light transmittance and a low water vapor permeability, such as SiOx or polyvinylidene chloride, is formed as a barrier layer on both surfaces of a plastic film sheet.

However, these film formations are often performed by vacuum processes, laminating, coating, etc., and it is difficult to treat the side surface of the plastic film sheet, and in the case of a liquid crystal display device,
This is more difficult and generally not done because it is necessary to form a plurality of cells on one large substrate at a time and then cut and form a film on the side surface with the driver connected. In this case, in an environment where the humidity is extremely high, particularly in the case of a display device using polarized light such as a liquid crystal display device using nematic liquid crystal or an electroluminescence (EL) display device using a circularly polarizing plate, the four corners of the display section are used. In some cases, display unevenness may occur in the periphery or in the vicinity, which is a problem.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to prevent display unevenness of a display device during the process and after completion of the device when plastic is used as a substrate.

[0005]

The present inventors have presumed that the display unevenness is caused by the following causes. That is, when a plastic substrate having a water vapor barrier layer on the surface thereof is placed in a high humidity environment, water vapor diffuses from the side surface having no barrier layer, and the dimensional change due to water absorption differs between the side surface and inside the surface. The substrate tries to swell and expand in the vicinity and the four corners close to the side surface, and in the plastic material having high photoelasticity, the retardation is particularly increased, which causes display unevenness when the display device is a device using polarized light. It is considered to be a thing. In order to prevent this, a barrier layer that can be removed at the same time as the electrode formation is provided as a barrier layer on the outer surface of the display device, so as to prevent dimensional change of the plastic substrate due to moisture absorption that occurs during the manufacturing process such as color filters. In addition to addressing this problem, after the color filters are laminated, the water vapor permeability of the substrate can be determined by removing the barrier layer that can be removed at the same time as the etching process during electrode formation. The above problem can be solved by forming a barrier layer that does not cause a significant difference in internal distribution and has a water vapor permeability of a level that can sufficiently block water vapor on the inner surface when used as a display device. As a result, the following inventions have been reached.

That is, the present invention is (1) Electrodes on one side of the plastic film sheet
Having a barrier layer that can be simultaneously removed during formation, and the other
Water vapor permeability of 0.1g / m²Less than / day
An optical film sheet having a single layer or a composite layer. (2) One side of the plastic film sheet is steamed with water.
Air permeability of 10g / m² / Day or more 50g / m²/ Da
y or less at the same time when forming an electrode and a single layer or composite layer
It has a removable barrier layer and has a water vapor permeable surface on the other side.
Excessive 0.1 g / m²/ Day or less single layer or
An optical film sheet having a composite layer. (3) The barrier layer that can be removed at the same time when the electrodes are formed is ITO
The optical film sheet of (1) or (2). (4) Retardation of the plastic film sheet
(1) to (3) for which the thickness is 20 nm or less
Musheet. (5) When forming electrodes on the plastic film sheet
550 after removing the simultaneously removable barrier layer
The light transmittance in nm is 80% or more (1) to
The optical film sheet of (4). (6) The photoelastic constant of the plastic film sheet is
10 x 10^-13cm²/ Dyn or more (1) to (5)
Optical film sheet. (7) The plastic film sheet is (1) Esthetic
Polymer having a repeating unit bound by a le bond,
(2) Having a repeating unit bound by a carbonate bond
Polymer or (3) sulfone bond
(1) to (6) whose main component is a polymer having a return unit
Optical film sheet. (8) The plastic film sheet is polyether
(7) Optical film sheet containing sulfone as a main component
To. (9) The optical film sheet according to (1) to (8).
Has a water vapor permeability of 0.1 g / m²/ Day or less
The side with a single layer or composite layer is used as the inner surface of the device
In the etching process when forming the electrode on the inner surface side,
A barrier layer that can be removed at the same time when the electrodes on the outer surface are formed
A method for manufacturing a display device, which is characterized by removing. (10) The table of (9), wherein the display device is a liquid crystal display device.
Manufacturing method of the indicating device. Is.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the optical film sheet of the present invention, there is no significant difference in the in-plane distribution of the amount of water infiltrated into the plastic which is the center of the substrate, and during the manufacturing process of color filters and the like. In order to prevent problems with dimensional change, the barrier layer on the outer surface of the display device can be simultaneously removed during electrode formation, and the inner surface can sufficiently block water vapor. A barrier layer having a level of water vapor permeability is formed. The barrier layer that can be removed at the same time when the electrodes are formed is not particularly limited, but ITO (indium tin oxide) made of the same material as the electrode layer,
Examples of the metal include aluminum and copper, and among these, ITO made of the same material as the electrode layer is preferable. In addition, the water vapor permeability of the lower layer of the barrier layer, which can be removed at the same time as the electrode formation, is 10 g / m ² / day or more and 50 g / day or more.
A rough barrier layer composed of a single layer or a composite layer having a m ² / day or less may be formed. If the water vapor permeability of the rough barrier layer is less than the lower limit value, the barrier property is too high, and the moisture absorption concentration distribution may occur due to the infiltration of water vapor from the side surface and the diffusion in the plastic, which may increase the retardation. Further, if the water vapor permeability is equal to or higher than the upper limit value, it is meaningless as a barrier layer. On the other hand, a single layer or a composite layer having a water vapor permeability of 0.1 g / m ² / day or less can be used as the barrier layer on the inner surface of the display device. If the water vapor permeability of the barrier layer on this surface is high, water vapor infiltrates into the liquid crystal or the EL element to lower the specific resistance and cause display failure.

Water vapor permeability of 10g which is a rough barrier
/ M ² / day or more and 50 g / m ² / day or less, a barrier layer may be formed by coating an organic barrier layer such as polyvinylidene chloride to a required thickness, or by forming Si or Ti. , Zr, Al, Ta, Nb,
An inorganic barrier layer such as an oxide such as Sn, a nitride, or a halide can be formed by vacuum vapor deposition, CVD, sputtering, or the like. Further, the organic layer and the inorganic layer can be stacked to form a film. By selecting these composition and film thickness,
The water vapor permeability can be controlled within the above range. On the other hand, the film formation of a single layer or a composite layer having a water vapor transmission rate of 0.1 g / m ² / day or less is performed using Si, Ti, Zr, A
Obtained by depositing an inorganic barrier layer of oxides, nitrides, halides, etc. of 1, 1, Ta, Nb, Sn, etc. by vacuum vapor deposition, CVD, sputtering, etc., or by stacking these with an organic film. You can Furthermore, the transparent conductive material I
TO (indium tin oxide) also has a gas / water vapor permeability of 0.
Since it can be 1 g / m ² / day or less, in the case of a common electrode side substrate of a TFT-LCD in which a transparent electrode is formed on the entire surface, the ITO electrode may be used in some cases. In this case, if necessary, the electrode surface may be masked with a resist or the like to remove the removable barrier layer on the outside.

The optical film sheet of the present invention preferably has a retardation of 20 nm or less. When the retardation film is used in addition to the retardation film, if the retardation exceeds 20 nm, the display unevenness of the display device may be defective even if the retardation does not increase due to moisture absorption. Furthermore, the optical film sheet of the present invention is particularly effective when a plastic film sheet having a photoelastic constant of 10 × 10 ⁻¹³ cm ² / dyn or more is used. In a plastic film sheet with a photoelastic constant of 10 × 10 ^-13 cm ² / dyn or less, the retardation increase due to stress is small, so it is displayed even if the water vapor permeability of both barrier layers is 0.1 g / m ² / day or less. Although the problem of causing display unevenness is unlikely to occur in the device, many plastics having low photoelastic constants generally have low heat resistance such as aliphatic polymers, and their use is often limited as a display device substrate. The plastic used for the optical film sheet of the present invention is not particularly limited, but preferred examples include (1) a polymer having a repeating unit bonded by an ester bond such as polyester or polyarylate, (2) a polycarbonate and the like. A plastic having a polymer having a repeating unit bound by a carbonate bond or (3) a polymer having a repeating unit bound by a sulfone bond such as polysulfone as a main component. These may be used alone or in combination of two or more.
Further, a lubricant, a heat resistance stabilizer, a weather resistance stabilizer, a pigment, a dye, an inorganic filler and the like may be appropriately blended. Since there is a step of heating to about 150 ° C. in the manufacturing process of the display device, a plastic having excellent heat resistance is preferable. Those containing a polymer as a main component are preferable. In particular, polyether sulfone is preferable from the balance of heat resistance and transparency described below.

The optical film sheet of the present invention has a wavelength of 55.
The light transmittance at 0 nm is preferably 80% or more. When the light transmittance is low, the display is dark and difficult to see when used as a display device, or the power consumption is high in order to make the display bright. Although this problem gradually becomes a problem as the light transmittance decreases, it is practically preferable that the light transmittance at a wavelength of 550 nm is 80% or more, except for a semi-transmissive display substrate.

[0011]

[Examples] Hereinafter, detailed description will be given based on examples.
The present invention is not limited to this embodiment. <Example 1> Width 1 m thickness 18 produced by the solution casting method
Polycarbonate with 0 μm and retardation of 1 nm ± 1 nm
Both sides of the coating film, coater section, drying oven, high pressure mercury
Using a continuous coating machine with a UV irradiation device with a lamp,
Epoxy acrylate resin as UV curable resin composition
25 parts by weight of fat, 10 parts by weight of urethane acrylate resin,
As a photopolymerization initiator, Irgacure 907 (Ciba Spa)
Charity Chemicals) 1 part by weight, silane coupling
Γ-mercaptopropyltrimethoxysilane as a coating agent
A mixed solution of 0.2 parts by weight and 65 parts by weight of butyl acetate (hereinafter referred to as purple
It is referred to as an outer line curable resin composition A. ) Is applied and 120 degreeC
After drying at 350mJ / cm² Irradiated film thickness 2μ
m coating layer was provided. Samples collected in this process
The moisture vapor permeability of the film at 40 ° C and 90% RH is measured.
40g / m²/ Day
It was The polycarbonate used had a photoelastic constant of 96 ×
10^-13cm²Was / dyn.

Subsequently, a silicon oxide film having a thickness of 50 nm was formed on one surface of this film by using a continuous sputtering apparatus. The silicon oxide film uses silicon as a raw material target,
After depressurizing the inside of the sputtering apparatus to 10 ⁻³ Pa or less, argon was introduced as a discharge gas at a partial pressure of 0.04 Pa and oxygen was introduced as a reaction gas at a partial pressure of 0.04 Pa to carry out reactive sputtering to form a film. The ultraviolet curable resin composition A was again applied onto this silicon oxide layer by the same method as described above to form a coat layer. The water vapor transmission rate of the film sampled in this step is measured by a gas chromatography type gas / water vapor transmission rate measuring instrument G manufactured by Yanako Analytical Industry Co., Ltd.
It was 0.002 g / m ² / day when measured using TR-30 (hereinafter referred to as a water vapor transmission rate measuring machine).

Next, a solution of 10 parts by weight of polyvinylidene chloride and 90 parts by weight of methylene chloride was applied to the surface opposite to the surface on which the silicon oxide film was formed by using the continuous coating machine described above.
The coating layer was dried to form a coating layer having a thickness of 2 μm, and the ultraviolet curable resin composition A was applied again in the same manner as above to form a coating layer. In order to measure the water vapor permeability of the polyvinylidene chloride and the coat layer, a sample without the above silicon oxide film and the coat layer above it was prepared and measured using a water vapor permeability measuring device to obtain 12 g / m 2. It was ² / day. Further, on the coat layer, In, Sn (SnO ₂ 10 wt.
%) In and Sn with a thickness of 300 Å by planar magnetron sputtering using an alloy oxide target of
An alloy oxide film was formed. In addition, I of this optical film
The light transmittance at a wavelength of 550 nm after removing the n and Sn alloy oxide films was measured by a spectrophotometer.
It was 3%.

The optical film before removing the In, Sn alloy oxide film was cut into a sheet of 360 mm × 460 mm to obtain a display element substrate. The following tests were conducted in order to evaluate the dimensional change due to repeated heating / drying of the photoresist and development / etching with an aqueous solution in the photolithography process of forming the color filter layer and forming the transparent electrode for display. First, the substrate is dried at 120 ° C for 1 hour, then left to stand in the drying container until the substrate temperature reaches 23 ° C, the outer dimensions are measured by the precision dimension measuring device, and then immersed in pure water at 23 ° C for 5 minutes. After that, measure the outer dimensions again. This operation was repeated again, and the ratio of the swing width to the first measured value was obtained. The dimensional change thus obtained was 0.002%.

Next, this optical film was subjected to 10 ° C. at 40 ° C.
% Aqueous solution of hydrochloric acid for about 5 minutes to etch ITO, wash with water, and dry. This step is a step generally performed when forming the transparent electrode for display. Then, in order to perform retardation evaluation under high temperature and high humidity conditions, first,
The substrate was cut into an outer size of 40 mm × 60 mm assuming a small display device, and the retardation of the portion 3 mm in the vertical and horizontal directions from the four corners was measured with a polarizing microscope equipped with a Berek compensator. Retardation is 1-2 nm
Met. This substrate was placed in a thermo-hygrostat set at 60 ° C. and 90% RH, and the retardation was measured at the same position as above every 240 hours for 240 hours and then every 100 hours for 1040 hours. Has a maximum value of 4 nm.

<Example 2> Width 1 m produced by the melt extrusion method
A coat layer of acrylate having a thickness of 2 μm was provided on both surfaces of a polyethersulfone film having a thickness of 200 μm and a retardation of 4 nm ± 2 nm in the same manner as in Example 1. The film sampled in this process is 40 ℃ 90
The water vapor permeability at% RH was measured by the cup method and found to be 50 g / m ² / day. The photoelastic constant of the polyether sulfone used is 100 × 10 ^-13 c
It was m ² / dyn. Then, a silicon oxide film having a thickness of 50 nm was formed on one surface of this film by using a continuous sputtering apparatus. The silicon oxide film uses silicon as a raw material target, decompresses the inside of the sputtering apparatus to 10 ⁻³ Pa or less, introduces argon as a discharge gas at a partial pressure of 0.08 Pa, and oxygen as a reaction gas at a partial pressure of 0.08 Pa. The film was introduced and reactive sputtering was performed to form a film. The ultraviolet curable resin composition A was applied again on this silicon oxide layer by the same method as in Example 1 to form a coat layer. The water vapor permeability of the film sampled in this step was measured with a water vapor permeability measuring device and found to be 0.06 g / m ² /
It was a day.

Next, on the surface opposite to the surface on which the silicon oxide film is formed, I having a relative weight density of 95% or more with respect to the bulk is formed.
An In, Sn alloy oxide film having a thickness of 300 Å was formed by planar magnetron sputtering using an n, Sn (SnO2 10 wt%) alloy oxide target. The light transmittance at a wavelength of 550 nm after removing the In and Sn alloy oxide films of this optical film was measured by a spectrophotometer and found to be 90%.

Example 1 of the obtained optical film
When the dimensional change was determined in the same manner as above, it was 0.003%. After peeling the ITO in the same manner as in Example 1,
When the retardation was evaluated under the high temperature and high humidity condition, the maximum value of the retardation was 6 nm.

Example 3 20 parts by weight of a urethane acrylate resin as an ultraviolet curable resin composition, 70 parts by weight of isocyanuric acid triacrylate, and 1 part by weight of Irgacure 907 (manufactured by Ciba Specialty Chemicals) as a photopolymerization initiator. Part, and a mixed solution of 5 parts by weight of methyl cellosolve acetate are cast on a polishing glass whose surface is evenly coated with a release agent, dried in an oven at 90 ° C. for 30 minutes, and then exposed to ultraviolet rays from above and below the substrate by a high pressure mercury lamp. From each 200m
The UV curable resin composition was cured by irradiation with J / cm ² . After peeling the cured product from the substrate, 40 from the top and bottom
It was irradiated with ultraviolet rays of 0 mJ / cm ² and then treated in an oven at 150 ° C. for 2 hours while being sandwiched between polishing glasses to obtain a plastic sheet having a thickness of 0.4 mm and an outer shape of 300 mm × 300 mm. 40 ℃ 90% RH of this sheet
When the water vapor permeability in was measured by the cup method,
It was 20 g / m ² / day. Further, the retardation of this plastic sheet was 0 to 1 nm, and the photoelastic constant was 4 × 10 ⁻¹³ cm ² / dyn.

Subsequently, a silicon oxide film having a thickness of 50 nm was formed on one surface of this sheet by using a single-wafer sputtering apparatus. The silicon oxide film uses silicon as a raw material target, decompresses the inside of the sputtering apparatus to 10 ⁻³ Pa or less, introduces argon as a discharge gas at a partial pressure of 0.04 Pa, and oxygen as a reaction gas at a partial pressure of 0.04 Pa. The film was introduced and reactive sputtering was performed to form a film. The ultraviolet curable resin composition A was again spin-coated on this silicon oxide layer,
After drying on a hot plate at 0 ° C. for 2 minutes and further on a hot plate at 120 ° C. for 2 minutes, ultraviolet rays were cured at 400 mJ / cm ² by a high pressure mercury lamp to cure, and a coat layer was provided. The water vapor transmission rate of the film sampled in this step was measured by using a water vapor transmission rate measuring device.
It was 002 g / m ² / day.

Then, a silicon oxide film having a thickness of 20 nm was formed on the surface opposite to the surface on which the silicon oxide film was formed, using a single-wafer sputtering apparatus. The silicon oxide film uses silicon as a raw material target, decompresses the inside of the sputtering apparatus to 10 ⁻³ Pa or less, and then uses argon as a discharge gas at a partial pressure of 0.15 Pa.
Oxygen was introduced as a reaction gas at a partial pressure of 0.15 Pa, and reactive sputtering was performed to form a film. The ultraviolet curable resin composition A was coated again on this silicon oxide layer by the same method as described above to form a coat layer, and an optical film was obtained. In order to measure the water vapor permeability of the silicon oxide film formed a second time and the coating layer, a sample without the silicon oxide film of the first time and the coating layer above it was prepared and used with a water vapor transmission rate measuring device. When measured with 0.8g / m
It was ² / day. The light transmittance of this optical film at a wavelength of 550 nm was 88% when measured with a spectrophotometer.

Next, an Al thin film having a thickness of 300 Å was formed on the surface opposite to the surface on which the silicon oxide film was formed by planar magnetron sputtering using an Al target. When the dimensional change of the obtained film was determined in the same manner as in Example 1, it was 0.003%. Further, when the retardation was evaluated under high temperature and high humidity conditions after removing the Al thin film in the same manner as in Example 1, the maximum value of the retardation was 1 nm.

Example 4 A liquid crystal display device was produced using the film with ITO of Example 2 as a substrate. First
In the step of, a color filter layer was formed. The color filter layer is made of resin black matrix material, R, G,
Water vapor permeability of 0.06 g / m ² / da by photolithography using 3 kinds of pigment-dispersed color resists of B.
Formation was performed on the barrier layer deposition surface side of y. The size of the R, G, B color resists was 70 μm × 200 μm, and a black matrix was formed between them with a width of 10 μm. The outer size of the black matrix was 40 mm × 60 mm, and the color filter formation range was 30 mm × 50 mm. Further, a color filter overcoat material was applied by a spin coater and cured in an oven at 170 ° C. for 1 hour.

In the second step, a transparent electrode was formed, and at the same time, the ITO film on the side opposite to the electrode was removed. That is, a substrate on which a color filter is formed has a water vapor permeability of 0.06 g / m ² / d on a color filter forming surface and a substrate on which a color filter used in combination is not formed.
A film of indium tin oxide (ITO) having a thickness of 100 nm was formed by a single-wafer sputtering apparatus on the barrier layer formation surface side of ay, patterned into stripes by photolithography, and then etched to form a transparent electrode. The ITO film on the opposite side was removed during this etching.

An orienting agent was printed / film-formed on the patterned transparent electrode, rubbed to give a 240 ° twist orientation, washed, and dried. Next, a sealing material was screen-printed on the substrate on which the color filter was not formed, and prebaking was performed. Meanwhile, spacers were scattered on the side of the substrate on which the color filter was formed. The spacers used had an adhesive coating. Subsequently, the two substrates were bonded together, and the sealing material was completely cured to form a cell. Z as a liquid crystal in the cell made by Merck
Injecting a composition in which a chiral agent is added to LI2293,
A sealing material was used to obtain a liquid crystal cell. Further, a retardation film and a polarizing film were attached to the liquid crystal cell to obtain a liquid crystal display device.

A drive waveform generator was connected to the produced liquid crystal display device for display. Display unevenness was not observed when the entire surface was turned on and when it was not turned on, which was good. In addition, the liquid crystal display device 60
When the sample was placed in a constant temperature and humidity chamber of 90% RH at 90 ° C. and tested for a change in the display due to the treatment, a display time of 1000 hours was tested, and no display unevenness occurred.

<Comparative Example 1> Width 1 m produced by the melt extrusion method
In the same manner as in Example 1, a coating layer having a thickness of 2 μm was provided on both sides of a polyethersulfone film having a thickness of 200 μm and a retardation of 4 nm ± 2 nm. The water vapor permeability of the film sampled in this step at 40 ° C. and 90% RH was measured by the cup method to be 50 g / m ^2.
Was / day. The photoelastic constant of the polyether sulfone used was 100 × 10 ⁻¹³ cm ² / dyn. Then, a silicon oxide film having a thickness of 50 nm was formed on one surface of this film by using a continuous sputtering apparatus.
The silicon oxide film uses silicon as a raw material target, decompresses the inside of the sputtering apparatus to 10 ⁻³ Pa or less, introduces argon as a discharge gas at a partial pressure of 0.08 Pa, and oxygen as a reaction gas at a partial pressure of 0.08 Pa. The film was introduced and reactive sputtering was performed to form a film. The ultraviolet curable resin composition A was applied again on this silicon oxide layer by the same method as in Example 1 to form a coat layer. The water vapor transmission rate of the film sampled in this step was measured by using a water vapor transmission rate measuring device and found to be 0.06 g / m ² / day.

Then, a silicon oxide film having a thickness of 20 nm was formed on the surface opposite to the surface on which the silicon oxide film was formed, using a continuous vacuum vapor deposition apparatus, to obtain an optical film. In addition, in order to measure the water vapor permeability of the silicon oxide film formed a second time, a sample without the silicon oxide film of the first time and the coating layer above it was prepared and measured using a water vapor permeability measuring device. However, it was 15 g / m ² / day. The light transmittance of this optical film at a wavelength of 550 nm was 89% when measured with a spectrophotometer.

About the Optical Film Obtained Example 1
When the dimensional change was obtained in the same manner as in, it was 0.01%. Further, when the retardation was evaluated under the high temperature and high humidity condition in the same manner as in Example 1, the maximum value of the retardation was 7 nm.

Using this optical film as a substrate,
An attempt was made to manufacture a liquid crystal display device. When a color filter layer was formed in the same manner as in Example 4, misalignment occurred when photolithography was repeated and a gap was formed between the black matrix and the R, G, B color resists. A defect such as a partial overlap occurred.

<Comparative Example 2> Width 1 m produced by the melt extrusion method
In the same manner as in Example 1, a coating layer having a thickness of 2 μm was provided on both surfaces of a polyethersulfone film having a thickness of 300 μm and a retardation of 6 nm ± 2 nm. The water vapor permeability of the film sampled in this step at 40 ° C. and 90% RH was measured by the cup method to be 50 g / m ^2.
Was / day. The photoelastic constant of the polyether sulfone used was 100 × 10 ⁻¹³ cm ² / dyn. Then, a silicon oxide film having a thickness of 50 nm was formed on one surface of this film by using a continuous sputtering apparatus.
The silicon oxide film uses silicon as a raw material target, decompresses the inside of the sputtering apparatus to 10 ⁻³ Pa or less, introduces argon as a discharge gas at a partial pressure of 0.04 Pa, and oxygen as a reaction gas at a partial pressure of 0.04 Pa. The film was introduced and reactive sputtering was performed to form a film. The ultraviolet curable resin composition A was applied again on this silicon oxide layer by the same method as in Example 1 to form a coat layer. The water vapor permeability of the film sampled in this step was 0.002 g / m ² / day when measured using a water vapor permeability meter.

Then, a silicon oxide film having a thickness of 50 nm is formed on the surface opposite to the surface on which the silicon oxide film is formed in the same manner as described above, and the ultraviolet curable resin composition A is formed thereon. A coating layer was formed by coating in the same manner as in Example 1. In order to measure the water vapor permeability of the silicon oxide film formed the second time, a sample without the silicon oxide film of the first time and the coating layer as the upper layer was prepared and measured using a water vapor permeability measuring device. It was 0.002 g / m ² / day. The light transmittance of this optical film at a wavelength of 550 nm was 89% when measured with a spectrophotometer.

Example 1 of the obtained optical film
When the dimensional change was determined in the same manner as above, it was 0.002%. Further, when the retardation was evaluated under the high temperature and high humidity condition in the same manner as in Example 1, the maximum value of the retardation was 41 nm.

Using this optical film as a substrate,
A liquid crystal display device was produced in the same manner as in Example 4. A drive waveform generator was connected to the produced liquid crystal display device for display. Display unevenness was not observed when the entire surface was turned on and when it was not turned on, which was good. When this liquid crystal display device was placed in a constant temperature and constant humidity chamber at 60 ° C. and 90% RH and tested for changes in the display due to the treatment, uneven display occurred from the four corners of the display section for about 50 hours.

In Examples 1 to 4, optical film sheets suitable for use as substrates for display devices, which have small dimensional changes and small increase in retardation due to high-temperature and high-humidity treatment, are obtained. Example 2
Good display could be performed even when a display device was manufactured using the optical film of (Example 4).

On the other hand, in Comparative Example 1, one surface has a single layer or a composite layer having a water vapor permeability of 0.1 g / m ² / day or less, but the other surface has a water vapor permeability of 15 g / day. Since it was as large as m ² / day, the color filter could not be formed well. Further, in Example 2, the water vapor permeability is 0.002 g / m ² / d on both sides.
Since it was as small as ay or less, the increase in retardation due to the high temperature and high humidity treatment was large, and display unevenness occurred under high temperature and high humidity conditions when used as a display device.

[0037]

As described above, the optical film sheet of the present invention imparts the water vapor barrier property necessary for the protection of the element to the inner surface of the substrate and removes the outer surface simultaneously with the electrode formation. To provide a possible barrier layer,
In the photolithography process of color filter formation, the photoresist is dried by heating and developed with an aqueous solution.
It is possible to cope with the dimensional change of the sheet due to repeated resist removal. Further, the method for manufacturing a display device of the present invention, in which the removable barrier layer is removed at the time of forming the electrode, does not cause a significant difference in the in-plane distribution of the amount of moisture infiltrated into the plastic that is the center layer of the substrate, It is possible to eliminate the display unevenness at the four corners of the display part that occurred on the plastic substrate, and to have a barrier layer with a water vapor permeability of a level that can sufficiently block water vapor on the inner surface when forming a display device. A display device having excellent display performance and stability is provided.

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Claims (10)

[Claims] 1. A plastic film sheet having a barrier layer which can be simultaneously removed at the time of forming an electrode on one surface, and a water vapor permeability of 0.1 g / m ² / day on the other surface.
An optical film sheet having the following single layer or composite layer. 2. A plastic film sheet having a water vapor transmission rate of 10 g / m ² / day or more and 50 g / day or more on one surface thereof.
a single layer or a composite layer having a m ² / day or less and a barrier layer that can be simultaneously removed during electrode formation, and a single layer having a water vapor permeability of 0.1 g / m ² / day or less on the other surface; An optical film sheet having a composite layer. 3. The optical film sheet according to claim 1, wherein the barrier layer that can be simultaneously removed when forming the electrode is ITO. 4. The optical film sheet according to claim 1, wherein the retardation of the plastic film sheet is 20 nm or less. 5. The optical according to any one of claims 1 to 4, wherein the plastic film sheet has a light transmittance of 80% or more at a wavelength of 550 nm after removing a barrier layer that can be simultaneously removed during electrode formation. Film sheet for. 6. The optical bullet of the plastic film sheet
The sex constant is 10 × 10^-13 cm²/ Dyn or more
An optical film sheet according to any one of 1 to 5. 7. The plastic film sheet is (1) a polymer having repeating units bound by ester bonds, (2) a polymer having repeating units bound by carbonate bonds, or (3) bound by a sulfone bond. The optical film sheet according to claim 1, which comprises a polymer having a repeating unit as a main component. 8. The optical film sheet according to claim 7, wherein the plastic film sheet contains polyether sulfone as a main component. 9. The optical film sheet according to claim 1, wherein the side having a single layer or a composite layer having a water vapor permeability of 0.1 g / m ² / day or less is used as an inner surface of the device, A method for manufacturing a display device, characterized in that, in an etching step for forming an electrode on the inner surface side, a barrier layer that can be removed at the same time as the electrode on the outer surface side is removed. 10. The method of manufacturing a display device according to claim 9, wherein the display device is a liquid crystal display device.