JP3244079B2 - Liquid crystal panel and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of any harm due to cell gap difference within a display area, namely generation of a luminance unevenness, even if there are projecting and recessing parts on substrates owing to a light shielding layer and to obtain a liquid crystal panel with a uniform display within its panel surface. SOLUTION: In the liquid crystal panel, a spacer 7 on a light shielding layer 9 is sealed and hardened in a compressed (crushed) state expressed as 7a in the figure, cell thickness of the liquid crystal panel gets fixed almost constant in a region extending from the center of a display area to the boundary light shielding layer part, gap unevenness at the boundary part generated with projecting and recessing parts between the display area and the peripheral light shielding layer 9 disappears and a luminance unevenness in this region becomes totally unobservable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal panel having a uniform display over substantially the entire surface of the liquid crystal panel.

[0002]

2. Description of the Related Art A liquid crystal display device is a display device in which the initial alignment direction of a liquid crystal is changed to another alignment state by an action utilizing the anisotropy of the liquid crystal, and a change in optical characteristics accompanying the change is performed. In recent years, large screens and large capacities have been realized because they can be driven at a lower voltage than conventional display devices such as CRTs, are suitable for LSI driving, are of a low power consumption type, and can be made thinner and lighter. Due to the development, development is being pursued with the aim of mounting on OA equipment, and it is being commercialized.

At present, the main axis is a simple matrix type STN type display utilizing change in alignment state by application of an electric field of liquid crystal, that is, electro-optical characteristics, followed by an active matrix type TFT display. The liquid crystal display is a sandwich type in which liquid crystal is sandwiched between a pair of glass substrates on which a transparent electrode film is formed, and a polymer thin film for aligning the liquid crystal is formed on the transparent electrode film. In the case of STN type display, the cell thickness between substrates is 5
The orientation of the liquid crystal is controlled by rubbing on a polymer thin film to give a pretilt angle of about 3 to 8 °. The STN method utilizes the birefringence of liquid crystal and the optical rotation of light, and adjusts the orientation of liquid crystal between a pair of substrates by 180 degrees.
Since it is possible to obtain a remarkably steep threshold characteristic by twisting {-270}, the cell thickness requires an accuracy of 0.05-0.1 μm.

The optical characteristics of a liquid crystal panel can be obtained by the birefringence and dielectric anisotropy of the liquid crystal molecules. The liquid crystal material is adjusted by adjusting the composition of the liquid crystal material used, including the viscosity and elastic constant, and the component ratio thereof. The optical properties of the panel change. At present, various liquid crystal materials are being developed, and desired characteristics can be obtained by mixing liquid crystal materials. Finally, Δnd, which is the product of the birefringence Δn of the liquid crystal and the thickness d of the liquid crystal layer,
The panel characteristics are determined by the combination of the optical compensation configuration using the retardation film.

The production of liquid crystal panels whose optical properties have been determined is usually carried out by a dropping method (disclosed in JP-A-63-179328).
Alternatively, the desired liquid crystal is sandwiched between the substrates by a vacuum injection method.In particular, in the liquid crystal dropping method, a spacer is dispersed on one glass substrate, and the liquid crystal prepared in several cylinders is transferred to the other glass substrate. This is a method that is performed by dropping a fixed pulse on the top.

[0006]

However, when unevenness is present on the substrate in which the spacers are dispersed, gap unevenness occurs according to the unevenness of the substrate if the spacer diameter is uniform. In general, a light-shielding layer is provided around the display area of the color filter used in the current color liquid crystal panel in order to improve the visibility of the display section. Combination, pigment, Cr
Thus, the light-shielding layer portion projects above the display area from the display area by the thickness of the light-shielding layer, thereby forming a convex portion. Therefore, when spacers having the same particle size are scattered, the cell thickness at the boundary with the light-shielding layer becomes thicker than that at the center of the display area, and this becomes a difference Δnd, which is recognized as luminance unevenness when the panel is turned on and off.

The present invention has solved this problem.
Provided is a liquid crystal panel capable of preventing a problem due to a difference in cell thickness in a display area, that is, preventing luminance unevenness from occurring even when unevenness due to a light shielding layer is present on a substrate, and enabling uniform display in a panel surface. The purpose is to do.

[0008]

The liquid crystal panel of the present invention comprises:
A pair of substrates for holding liquid crystal, and a pair of substrates
An electrode pattern provided on the display area of the substrate les, before
The display error of one of the pair of substrates.
In the non-display area around the rear, protrude from the other substrate
A light-shielding layer provided, and the display area of the one substrate;
Disposed inside and on the light shielding layer, between the pair of substrates.
A spacer for holding a gap, and the space on the light shielding layer.
Seal the sir with its particle size compressed, and
The particle size of the spacer in the display area is compressed.
UV curable resin that seals in a state where it is not
A liquid crystal panel, wherein the distance between the pair of substrates is
From the display area to the light shielding layer provided in the non-display area
Is substantially constant until the light-shielding layer
The unevenness of the brightness at the boundary is reduced by one tenth of the maximum transmittance.
The difference between the threshold voltages is as follows.
The difference between the threshold voltages was measured so that there was no difference when measured using a shape wave .

The method for manufacturing a liquid crystal panel according to the present invention comprises the steps of:
Electrodes are placed in the display area of each substrate.
Forming a pattern; and
Non-display area around the display area on one of the substrates
A light-shielding layer is formed so as to protrude from the other substrate.
And the display area and the non-display area of the other substrate.
Spray spacers with the same particle size in the display area
And dropping liquid crystal on the one substrate;
Ultraviolet light for sealing the pair of substrates on the other substrate
A step of printing a line-curable resin, and the step between the pair of substrates.
After bonding the pair of substrates so that the liquid crystal is sandwiched,
Curing the ultraviolet curable resin.
A method of manufacturing a panel, comprising curing the ultraviolet curable resin.
The step of holding the liquid crystal of the pair of substrates is
The operation is performed in a state where they are mutually pressurized through a pacer,
The spacer interposed between the optical layer and the other substrate
Liquid crystal that cures the ultraviolet curable resin in a compressed state
This is a panel manufacturing method .

Since the spacer interposed between the light-shielding layer and the substrate is sealed and fixed in a compressed state, the cell thickness from the panel display area to the vicinity of the light-shielding layer becomes substantially constant, and gap unevenness can be eliminated. .

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a liquid crystal panel of the present invention, FIG. 2 is a cross-sectional view thereof, and FIG. 3 is a simplified explanatory view showing main steps of a method of manufacturing a liquid crystal panel of the present invention. FIG.
2, reference numeral 1 denotes a glass substrate serving as a segment substrate, 2 denotes a glass substrate serving as a common substrate, and the glass substrate 1 is provided with a segment transparent electrode pattern 3 and the glass substrate 2 is provided with a common transparent electrode pattern 4. . Reference numeral 5 denotes a sealing material, and reference numeral 6 denotes an alignment film of polyimide, which is formed on the glass substrates 1 and 2 by a flexographic printing method, and after thermosetting, rubbing the surface to obtain a predetermined alignment. At this time, an orientation treatment is performed in a direction in which the liquid crystal molecules are twisted by 240 ° between the opposing glass substrates 1 and 2, and the spacers 7 having the same size of 7.0 μm are uniformly dispersed in the glass substrate 1. On the other glass substrate 2, the nematic liquid crystal 8 containing the chiral agent sucked into the three glass cylinders is dropped. Δn of this liquid crystal was set to 0.12. Ultraviolet (hereinafter abbreviated as UV) curable resin is used as the sealant 5 and a spacer is previously contained at a ratio of 1.5 wt%, and then printed on the glass substrate 1 on which the spacers 7 are dispersed by screen printing. Reference numeral 9 denotes a light-shielding layer.
It will protrude to the side.

Next, the glass substrates 1 and 2 are bonded together in a vacuum chamber to form a liquid crystal panel 12.
This is placed on a stage 10 shown in FIG.
While irradiating UV to the peripheral seal part through
Press plate by pressing machine from the direction opposite to this UV irradiation side
13 is pressed to cure the sealing material 5.

This sealing resin curing step is the essence of the present invention. In this case, the spacer 7 on the light shielding layer 9 is cured in a compressed (crushed) state as shown in FIG. The cell thickness of the liquid crystal panel from the center to the boundary of the light-shielding layer is substantially constant and fixed, and the gap unevenness at the boundary caused by the unevenness of the display area and the light-shielding layer 9 therearound is eliminated. Is not observed at all. On the other hand, using a liquid crystal panel manufactured by a normal method, the luminance unevenness generated at the boundary was measured as a voltage difference that can obtain the same luminance, and as a result, the threshold voltage was determined by a static waveform (a rectangular wave having a frequency of 64 Hz). (Transmittance 10 when maximum transmittance is 100%
%), Which was a luminance unevenness of 0.1 V.

Although the present embodiment has been described with reference to an STN type panel, the present invention is also applicable to a TFT type panel.

[0015]

According to the liquid crystal panel of the present invention , since the spacers on the light-shielding layer are seal-hardened in a compressed state,
The cell thickness of the liquid crystal panel up to the light shielding layer boundary portion from the display area center Ri Do substantially constant, the Kunar because such uneven gap of the boundary portion between the display area, uniform tables without luminance unevenness
Can be indicated. Also , a method for manufacturing a liquid crystal panel of the present invention
According to the ultraviolet resin curing step of sealing the liquid crystal panel, the liquid crystal holding surface of the substrate constituting the liquid crystal panel by performing at mutually pressurized state via a spacer, to the light-shielding layer near the display area Cell thickness is almost constant
Ri, Ltd. The liquid crystal panel capable of uniform display without uneven brightness
Ru can be granulated.

[Brief description of the drawings]

FIG. 1 is a plan view of a liquid crystal panel according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a liquid crystal panel according to an embodiment of the present invention.

FIG. 3 is a simplified explanatory view showing a main part of a manufacturing method of the liquid crystal panel manufacturing method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass substrate used as a segment substrate 2 Glass substrate used as a common substrate 3 Segment transparent electrode pattern 4 Common transparent electrode pattern 5 Seal material 6 Alignment film 7 Spacer 8 Liquid crystal 9 Light shielding layer 10 UV irradiation stage 11 UV mask 12 Liquid crystal panel 13 Press plate

Continuation of front page (56) References JP-A-64-76030 (JP, A) JP-A-5-303101 (JP, A) JP-A-7-20475 (JP, A) JP-A-1-62532 (JP) , U) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G02F 1/1339 G02F 1/1335 G02F 1/13 101

Claims (2)

(57) [Claims] 1. A pair of substrates sandwiching a liquid crystal, an electrode pattern provided in a display area of each of the pair of substrates, and the display of one of the pair of substrates.
In the non-display area around the area, project to the other substrate
A light-shielding layer provided in the display area of the one substrate and on the light-shielding layer.
And a spacer for maintaining a distance between the pair of substrates, and the spacer on the light shielding layer, the particle size of which is compressed.
In the display area and the space in the display area
Purple, which seals the laser without compressing its particle size.
And an outer line curing resin, wherein a distance between the pair of substrates is the distance from the display area.
The brightness unevenness is substantially constant up to the vicinity of the light shielding layer provided in the display area, and the boundary between the display area and the light shielding layer has uneven brightness.
Is the threshold voltage at which the transmittance is 1/10 of the maximum transmittance.
Measured using a square wave with a frequency of 64 Hz as the pressure difference
A liquid crystal panel characterized in that there is no difference between the threshold voltages when the threshold voltage is set . 2. A display area of each of a pair of substrates.
Forming an electrode pattern in a region to be formed, and displaying the display on one of the pair of substrates.
In the non-display area around the area, project to the other substrate
Forming a light-shielding layer as described above, and the display area and the non-display area of the other substrate.
A) a step of spraying spacers having the same particle size, a step of dropping liquid crystal on the one substrate, and a step of sealing the pair of substrates to the other substrate.
A step of printing an ultraviolet curing resin, and the pair of substrates so that the liquid crystal is sandwiched between the pair of substrates.
After bonding the substrates, the ultraviolet curing resin is cured
And a step of curing the ultraviolet-curable resin , the method comprising:
The surfaces holding the liquid crystal are mutually added via a spacer.
It is performed in a state of being pressed, and the light shielding layer and the other substrate
While the spacer interposed therebetween is compressed, the purple
A method of manufacturing a liquid crystal panel that cures an external curing resin.