JPH095733A - Liquid crystal display element - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a highly reliable liquid crystal display device, in which discoloration of a pigment or dye does not occur even when irradiated with ultraviolet rays. A first substrate having a first electrode layer on one main surface, and a second electrode layer arranged at a predetermined distance from the first substrate and facing the first electrode layer. A second substrate on one main surface, a color filter layer provided on the electrode layer side of at least one of the first and second substrates, and ultraviolet rays formed on the color filter layer. A protective layer having a blocking function and a liquid crystal composition layer sandwiched between the first and second substrates are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a highly reliable liquid crystal display device.

[0002]

2. Description of the Related Art At present, a liquid crystal display element which is generally used has a liquid crystal sandwiched between two glass substrates each having an electrode, and the periphery of these two substrates except for a liquid crystal sealing port. It has a structure in which it is fixed with an adhesive and the liquid crystal filling port is sealed with a sealing agent.

In the liquid crystal display element for color display among the liquid crystal display elements, a color filter having an RGB colored layer is formed on one of two glass substrates, and a light shielding layer is provided between pixels. Is formed as a black matrix. For example, in a simple matrix-driven color dot matrix liquid crystal display element, a Y substrate having Y electrodes patterned in a horizontal (Y) direction in a strip shape and an X electrode patterned in a strip shape in a vertical (X) direction are formed below the Y electrodes. An X substrate having a colored layer is disposed so as to face each other so that the Y electrode and the X electrode are substantially orthogonal to each other, and the liquid crystal composition is sandwiched between them.

As a display system of the liquid crystal display element, for example, a TN type, an ST type, a GH type, an ECB type or a system using a ferroelectric liquid crystal is used. As the sealant, for example, a heat- or UV-curable acrylic or epoxy adhesive is used.

Further, in the color type active matrix drive liquid crystal display element, for example, a thin film transistor (T) using amorphous silicon (a-Si) as a semiconductor layer is used.
FT), a display electrode and a signal line electrode connected to the thin film transistor, a TFT array substrate on which a gate electrode is formed, and a counter substrate having a counter electrode provided to face the TFT array substrate.
A color filter is formed and a liquid crystal composition is sandwiched between these two substrates. Further, polarizing plates are arranged on both sides of such a structure to display a color image as an optical shutter.

A color filter is used in the color display type liquid crystal display device described above, but this color filter must be transported from its manufacturing place to the liquid crystal manufacturing place, and dirt between the color filter and the organic substance is in between. May adhere to. In order to remove such dirt, irradiation with ultraviolet rays has been conventionally performed.

[0007] Usually, a protective film is formed on the color filter, but in order to improve the adhesion between the protective film and the transparent electrode formed thereon, ultraviolet rays may be irradiated. .

Furthermore, recently, a liquid crystal display element having a wide viewing angle has been proposed in which a plurality of good visual directions are formed in one pixel by changing the orientation direction and the pretilt angle in one pixel.
As one of the manufacturing methods of the liquid crystal display device having the wide viewing angle, a method of irradiating the alignment film with ultraviolet rays and controlling the pretilt angle to form a region having two or more viewing angle directions in one pixel is proposed. Has been done.

However, when the color filter substrate or the active matrix substrate is irradiated with ultraviolet rays in this way, the pigment or dye as a coloring material is discolored, and the reliability is lowered. Such a problem may be caused by the ultraviolet component of outside light.

[0010]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above problems, and it is
It is an object of the present invention to provide a highly reliable liquid crystal display device that does not cause discoloration of pigments and dyes.

[0011]

According to the present invention, there is provided a first substrate having a first electrode layer on one main surface, and the first electrode disposed at a predetermined distance from the first substrate. A second substrate having a second electrode layer facing the layer on one main surface,
A color filter layer provided on the electrode layer side of at least one of the first and second substrates, a protective layer having an ultraviolet blocking function formed on the color filter layer, and the first and second Provided is a liquid crystal display device including a liquid crystal composition layer sandwiched between a second substrate.

In the liquid crystal display device of the present invention, the protective layer formed on the color filter layer has a function of blocking ultraviolet rays, and the transmittance of light having a wavelength of 350 nm or less is preferably 10% or less, It is more preferably 0.1% or less. The reason why the transmittance of light having a wavelength of 350 nm or less is a problem is that light exceeding 350 nm does not adversely affect the color filter layer. Further, if the transmittance of light of 350 nm or less exceeds 10%, it cannot be said to have a sufficient ultraviolet ray blocking function.

The protective layer having an ultraviolet blocking function is specifically made of a resin containing an ultraviolet absorber. Examples of the resin include acrylic resin, acrylic modified epoxy resin, epoxy resin, and polyimide resin, and examples of the ultraviolet absorber include TINUVIN1130 (trade name, Ciba-Geigy-
Company).

The thickness of the protective layer is preferably 0.3 to 3.0 nm, and the amount of the ultraviolet absorber in the resin is 0.1.
It is preferably from 10 to 10% by weight. INDUSTRIAL APPLICABILITY The present invention can be suitably applied to an alignment division type liquid crystal display element, in which the alignment state of the alignment film is controlled by irradiating ultraviolet rays.

[0015]

As described above, in the liquid crystal display device of the present invention, since the protective layer of the color filter substrate is provided with the function of blocking ultraviolet rays, the ultraviolet ray component is incident and contaminants are conveyed when the color filter substrate is transported. Is removed, the adhesion between the protective layer and the transparent electrode is improved, and the irradiation of ultraviolet rays for controlling the alignment state of the alignment film does not cause discoloration of the color filter, thus ensuring high reliability. It is possible to obtain the liquid crystal display element of.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments of the present invention will be shown below with reference to the drawings to explain the present invention in detail. Example 1 FIG. 1 is a sectional view showing a configuration of a color filter substrate of a liquid crystal display element according to an example of the present invention. In FIG. 1, a black matrix 2 is formed in a lattice pattern on a glass substrate 1, and a colored layer 3 is provided on the glass substrate 1 exposed from the black matrix 2. Then, a protective layer 4 having an ultraviolet blocking function is formed on the colored layer 3.
And the counter electrode 5 is provided on the protective layer 4.

The protective layer 4 is made of an acrylic resin containing 10% by weight of TINUVIN 1130 as an ultraviolet absorber. The protective layer 4 has a transmittance of 0.2% for light having a wavelength of 350 nm or less, and has a function of effectively blocking ultraviolet rays.

Embodiment 2 FIG. 2 is a sectional view showing an active matrix liquid crystal display device according to another embodiment of the present invention. First, chromium oxide and chromium were sequentially formed on the glass substrate 11 by a sputtering method and selectively etched to form openings, thereby forming the black matrix 12. Then, the colored layer 13 is formed in the order of red, green, and blue, and the protective layer 14 having an ultraviolet blocking function is formed on the colored layer 13 by a roll coater.
It was formed with a film thickness of 1.2 μm. Further, the ITO film 15 is set to 1
A color filter substrate 10 was formed by forming a film having a thickness of 50 nm by a sputtering method.

The protective layer 14 is made of an acrylic resin containing 2% by weight of TINUVIN 1130 as an ultraviolet absorber. The protective layer 14 has a transmittance of 1% for light having a wavelength of 350 nm or less, and has a function of effectively blocking ultraviolet rays.

On the other hand, on the glass substrate 21, according to a conventional method,
By repeating the film formation and patterning, the display electrode 22 and the thin film transistor 23 are formed.
An amorphous silicon TFT array substrate 20 having 0000 pixels was formed.

After that, in order to improve the adhesion between the protective layer 14 of the color filter substrate 10 and the ITO film 15, only the color filter substrate 10 is irradiated with ultraviolet rays for 5 minutes, and then the alignment film material is formed on the ITO film 15. Was applied to the entire surface and rubbing treatment was performed to form an alignment film 16. On the other hand, after forming an alignment film material on the amorphous silicon TFT array substrate 20, a rubbing process was performed to form an alignment film 24.

Next, the adhesive 17 was printed along the periphery of the alignment film 16 of the substrate 10 except for the injection port (not shown). Then, on the surface of the substrate 10, a grain size of 6 as the gap material 18 is formed.
μm micropearl (manufactured by Sekisui Fine Chemical Co., Ltd.) was sprayed.

Next, the alignment films 16 and 24 are opposed to each other, the substrates 10 and 20 are arranged so that the rubbing directions of the alignment films are 90 degrees, and the adhesive 17 is cured by heating.
The substrates 10 and 20 were bonded together. Then, as a liquid crystal composition 25, ZLI-1565 was injected from the injection port by an ordinary method.
(Manufactured by E. Merck) was injected with 0.18 wt% of S811, and then the injection port was sealed with an ultraviolet curable resin.

After that, the color filter substrate 10 and the TF
A polarizing plate was arranged outside the T array substrate 20 to form a liquid crystal display cell, and a driving device was further connected to obtain a liquid crystal display device. When this liquid crystal display device is driven, even when a display is performed in a state where external light is strongly incident (for example, display outdoors),
There was no color change and a reliable display was obtained.

Embodiment 3 FIG. 3 is a sectional view showing an active matrix liquid crystal display device according to still another embodiment of the present invention. First, chromium oxide and chromium were sequentially formed on the glass substrate 31 from the substrate side by a sputtering method, and were selectively etched to form openings, thereby forming the black matrix 32. After that, a colored layer 33 was formed in the order of red, green, and blue, and a protective layer 34 having an ultraviolet ray blocking function was formed on the colored layer 33 by a roll coater to a film thickness of 1.2 μm. Furthermore,
The ITO film 35 was formed into a film having a thickness of 150 nm by a sputtering method to form the color filter substrate 30.

The protective layer 34 is made of an acrylic resin containing 5% by weight of TINUVIN 1130 as an ultraviolet absorber. The protective layer 34 has a transmittance of 0.4% for light having a wavelength of 350 nm or less, and has a function of effectively blocking ultraviolet rays.

On the other hand, on the glass substrate 41, according to a conventional method,
By repeating the film formation and patterning, the display electrode 42 and the thin film transistor 43 are formed.
An amorphous silicon TFT array substrate 40 having 0000 pixels was formed.

After that, an alignment film material was applied to the entire surface of the amorphous silicon TFT array substrate 40, and only the upper half of one pixel was irradiated with ultraviolet rays, and then a rubbing treatment was performed to form an alignment film 44. On the other hand, after the alignment film material is formed on the entire surface of the color filter substrate 30, only the lower half of one pixel is irradiated with ultraviolet rays to perform rubbing treatment,
The alignment film 36 was formed.

Next, an adhesive 37 was printed along the periphery of the alignment film 36 of the color filter substrate 30 except for the injection port (not shown). Then, the gap material 38 is formed on the surface of the substrate 30.
As a sample, Micropearl (made by Sekisui Fine Chemical Co., Ltd.) having a particle size of 6 μm was sprayed.

Next, the alignment films 36 and 44 are opposed to each other, the substrates 30 and 40 are arranged so that the rubbing directions of the alignment films are 90 degrees, and the adhesive is hardened by heating, so that the substrates 30 and 40 are aligned. 40 and 40 were pasted together. Then, as a liquid crystal composition 45, ZLI-156 was injected from the injection port by an ordinary method.
5 (manufactured by E. Merck & Co.) was injected with 0.18% by weight of S811, and then the injection port was sealed with an ultraviolet curable resin.

After that, the color filter substrate 30 and the TF
A polarizing plate was arranged outside the T array substrate 40 to form a liquid crystal display cell, and a driving device was further connected to obtain a liquid crystal display device. When driving this liquid crystal display device, in the initial state,
A product having very high color purity and good display performance was obtained.
Further, there was no change in color even after display for a long time, and a highly reliable display was obtained.

Comparative Example 1 An active matrix liquid crystal display device similar to that of Example 3 was prepared, except that the protective layer 34 was made of only acrylic resin containing no ultraviolet absorber. When driving this liquid crystal display device, in the initial state,
Particularly, the color of the color filter in the part irradiated with the ultraviolet rays was severely deteriorated, and the display was whitish as a whole.

[0033]

As described above, according to the present invention,
By providing the protective layer of the color filter substrate with an ultraviolet ray blocking function, it is possible to obtain a highly reliable liquid crystal display element with little discoloration.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a color filter substrate according to an embodiment of the present invention.

FIG. 2 is a sectional view showing an outline of a liquid crystal display element according to another embodiment of the present invention.

FIG. 3 is a sectional view showing an outline of a liquid crystal display element according to still another embodiment of the present invention.

[Explanation of symbols]

 1, 11, 21, 31, 41 ... Glass substrate, 2, 12, 32 ... Black matrix, 3, 13, 33 ... Colored layer, 4, 14, 34 ... Protective layer, 5, 15, 35 ... Counter electrode, 10 , 30 ... Color filter substrate, 16, 24, 36, 44 ... Alignment film, 17 ... Adhesive agent, 18 ... Spacer, 20, 40 ... Active matrix substrate, 22, 42 ... Display electrode 23, 43 ... Thin film transistor 25, 45 ... Liquid crystal composition

Claims (1)

[Claims] 1. A first substrate having a first electrode layer on one main surface, and a second electrode which is arranged at a predetermined distance from the first substrate and faces the first electrode layer. A second substrate having a layer on one main surface, a color filter layer provided on the electrode layer side of at least one of the first and second substrates, and a color filter layer formed on the color filter layer. A liquid crystal display device comprising: a protective layer having an ultraviolet blocking function; and a liquid crystal composition layer sandwiched between the first and second substrates.