JP2004246092A - Liquid crystal cell and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal cell of a totally new type in which adverse effect given by a conventional polarizing plate on display quality, moisture resistance, heat resistance and so on is reduced by utilizing a technique to form a polarizing plate with printing and a process for manufacturing the same. <P>SOLUTION: Transparent electrodes 2, SiO<SB>2</SB>films 3, polarizing films 4 and alignment layers 5 are laminated in this order on the inner sides of two sheets of glass substrates 1, a thin layer of a liquid crystal material 6 is interposed in between and the cell is air-tightly sealed by making a sealant 7 surround the periphery. The polarizing film 4 is film formed by using an aqueous solution of a dichroic dye as ink, applying the ink to a plate with many fine grooves along a printing direction so as to form a thin film and transferring and applying the thin film from the plate to the SiO<SB>2</SB>film. Liquid crystal molecules of the liquid crystal material 6 directly come into contact with the alignment layer 5. A cell gap corresponding to layer thickness of the liquid crystal material 6 is controlled with diameters of spacers 8. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a liquid crystal display, and more particularly to a structure of an effective liquid crystal cell to which a technique of forming a polarizing film by printing an ink of a dichroic dye and a method for manufacturing the same.
[0002]
[Problems to be solved by the invention]
Conventionally, polarizing plates disposed on both sides of a liquid crystal cell have been attached to the outside of the liquid crystal cell that has passed panel inspection using an adhesive.
For this reason, it is necessary to attach a polarizing plate to each of the liquid crystal cells divided by the scriber, and the workability is very poor.
In addition, various measures such as ensuring positioning accuracy and adhesion strength during bonding, preventing bubbles and dust from being mixed, and preventing the generation of static electricity are required, and in the subsequent process, the adhesion between the polarizing plate and the panel is strengthened or remains between the panels. A lot of time and effort has been spent on assembling such as performing autoclave processing to remove air bubbles.
[0003]
In order to solve this problem, the present applicant uses an aqueous solution of a dichroic dye developed by Optiva in the United States as ink, and prints this ink directly on a glass or plastic substrate with a normal flexographic printing apparatus to form a polarizing film. We have developed a manufacturing technology and applied for it earlier. This technology has made it possible to assemble a liquid crystal cell that does not require the work of attaching a polarizing plate, and has greatly increased the production efficiency of LCDs.
In addition, the conventional polarizing plate, which is disposed on the outermost surface of the LCD, greatly affects the display quality, moisture resistance, heat resistance, and the like of the entire display. Was also revealed at the same time.
[0004]
Accordingly, the present invention provides a completely new type of liquid crystal cell that reduces the influence on the display quality, moisture resistance, heat resistance, and the like of a conventional polarizing plate by using a technology of printing and forming a polarizing film, and manufacturing the same. It is intended to propose a process.
[0005]
[Means for Solving the Problems]
In order to achieve such an object, the present invention is configured as follows.
[0006]
That is, the liquid crystal cell of the present invention achieves the above object by forming a polarizing film, in which dichroic dyes are oriented in a certain direction, directly or indirectly on the inside of the cell.
[0007]
In addition, the method for manufacturing a liquid crystal cell of the present invention includes a patterning step of forming a transparent electrode on a washed substrate, an alignment processing step of applying an alignment film to the substrate, firing and rubbing, and dispersing spacers to form two substrates. A substrate laminating step of laminating the substrates, a panel dividing step of dividing the bonded substrates into panels of a predetermined size, a liquid crystal injecting step of injecting a liquid crystal material into the panels, In the liquid crystal cell assembling step comprising a polarizing plate attaching step of attaching a polarizing plate, a polarizing film printing / stabilizing step of printing and stabilizing a polarizing film by printing and stabilizing the substrate surface before the alignment treatment step is provided. It is characterized in that a polarizing plate attaching step is not required.
[0008]
Further, the method for producing a liquid crystal cell of the present invention is characterized in that, in the process of forming the polarizing film, the polarizing film other than the display region is etched using the pattern of the alignment film applied on the polarizing film as a resist. I do.
[0009]
In the method of manufacturing a liquid crystal cell according to the present invention, in the process of forming the polarizing film, the applied polarizing film is dried, and then the polarizing film is stabilized with an aqueous solution of BaCl ₂ (8 to 20 wt%). And
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0011]
FIG. 1 is a sectional view of a liquid crystal cell embodying the present invention.
The figure shows an example of a simple matrix type LCD such as an STN type.
In the liquid crystal cell, a transparent electrode 2, a SiO ₂ film 3, a polarizing film 4, and an alignment film 5 are sequentially laminated inside two glass substrates 1, sandwiching a thin layer of a liquid crystal material 6, and a sealing material 7 around the periphery. The cell is hermetically sealed around.
The polarizing film 4 is formed by using an aqueous solution of a dichroic dye as an ink, applying the ink to a plate having a large number of fine grooves along the printing direction to form a thin film, and transferring and applying the thin film from the plate. Film.
The liquid crystal molecules of the liquid crystal material 6 directly contact the alignment film 5, and the cell gap corresponding to the thickness of the liquid crystal material 6 is controlled by the diameter of the spacer 8.
When an alkali glass is used for the glass substrate 1, the alkali component may be dissolved in the liquid crystal, which may lower the contrast and the image quality.
Therefore, as shown in the figure, an SiO ₂ film 3 is formed between the transparent electrode 2 and the polarizing film 4 or between the glass substrate 1 and the transparent electrode 2 to undercoat the glass substrate 1.
[0012]
FIG. 2 shows a schematic diagram of a polarizing film printing apparatus.
The polarizing film printing apparatus uses an aqueous solution of a dichroic dye developed by Optiva in the United States as an ink, and applies this ink using a conventional flexographic printing apparatus or a coating apparatus that applies another shear force to the polarizing film. 4 is produced.
In the figure, a plate 11 having a number of fine grooves a along a printing direction is mounted on a plate cylinder 12, ink is dripped from a horizontally long dispenser 13 on a rotating plate 11, and spread by a blade 14 to spread the liquid. The color dye is pushed into the fine grooves a.
At this time, since the blade 14 is kept in contact with the plate 11 with a slight gap provided therebetween, a thin film of the ink liquid is formed on the plate surface.
Then, when the glass substrate 1 fixed on the printing table 15 passes directly below the plate cylinder 12, a thin film of this ink liquid is transferred and applied from the plate 11 to the glass substrate 1.
[0013]
FIG. 3 shows a flow of a manufacturing process of a liquid crystal cell embodying the present invention.
FIG. 4 shows a plan view and a cross-sectional view of the manufacturing process.
In the liquid crystal cell, first, an ITO film is formed on a well-cleaned glass substrate 1 by an evaporation method or a sputtering method, a resist material is applied thereon, a mask pattern is exposed, etching is performed, and a transparent electrode 2 is formed. Is patterned, and then the resist material is removed. (Step 101).
After the cleaning, the SiO ₂ film 3 corresponding to the electrode pattern is applied on the transparent electrode 2 by printing (step 102).
Next, the polarizing film 4 is printed using an ink for forming a polarizing film on the entire surface of the glass substrate 1 or applied by another coating device that applies a shearing force, and then dried (step 103).
When the polarizing film 4 is applied, the molecules of the dichroic dye of the polarizing film 4 are oriented in a certain direction by applying a shearing force using a bar coater, a slot die, a plate, or the like.
For stable application and drying, it is desirable that the temperature is 23 ° C. and the humidity is higher than 60%.
[0014]
Thereafter, the polarizing film 4 is stabilized, rinsed and dried (step 104).
Since the solvent for forming the polarizing film 4 is water, even after the coating is dried after drying, the film collapses when it comes into contact with water. Therefore, after drying, a stabilization treatment is performed to make it insoluble in water.
The stabilization process is performed by converting BaCl ₂ into an aqueous solution of 8 to 20 wt% and immersing the polarizing film 4 in the aqueous solution for 2 to 10 seconds. Thereafter, the substrate on which the polarizing film 4 has been applied is rinsed with pure water, excess BaCl ₂ aqueous solution is removed, pure water is cut off with an air knife, and the substrate is dried at about 80 ° C. to 120 ° C. to completely remove moisture from the substrate. To dry. By such a process, a thin film having a polarizing function can be formed on the entire surface of the substrate in a state stabilized in water or the like.
[0015]
Next, PI printing and curing are performed (step 105).
In the PI printing, a polyimide solution diluted with an organic solvent is applied by a flexographic printing apparatus, and a pattern of an alignment film 5 is printed on the polarizing film 4.
Curing is performed by drying the solvent at a heating temperature of about 80 ° C. and then baking to completely cure the polyimide.
[0016]
Next, etching, rinsing, and drying are performed (step 106).
In the etching, the polarizing film 4 where there is no alignment film 5 is dissolved out and removed by immersing the substrate in a several% aqueous alkali solution and then showering with pure water.
Thus, only the display area of the polarizing film 4 can be easily left.
The stabilized polarizing film 4 is also peeled off by coming into contact with an alkaline aqueous solution. The temperature of the chemical at this time is desirably about 20 ° C. to 40 ° C.
[0017]
Next, a rubbing process for rubbing the alignment film 5 in a certain direction is performed while rotating a roller around which a cloth such as rayon is wound, thereby aligning the alignment directions of the liquid crystal molecules in a certain direction (step 107).
It is considered that the polymer main chain of the alignment film polyimide is stretched in the rubbing direction by this treatment, and the liquid crystal molecules are arranged along the stretching direction.
[0018]
Next, spacers for controlling the cell gap are dispersed on one of the substrates (step 108).
Next, a sealing material for bonding and sealing the substrate and the counter substrate together is applied to the other substrate (step 109).
Next, the substrate on which the sealing material has been applied and the substrate on which the spacers have been scattered are accurately overlapped and bonded by pressure bonding (step 110).
Next, the bonded substrates are tightened by a heat press until a predetermined cell gap is reached, and the sealing material is cured by heating (step 111).
Next, division such as division into individual panels of a predetermined size from the multi-panel substrate is performed (step 112).
Next, a liquid crystal material is injected into the panel, and the liquid crystal material, dust, dirt, and the like attached to the panel after the injection port is sealed are washed (step 113).
Next, appearance inspection such as foreign matter and scratches, division failure, color unevenness between polarizers, cell gap unevenness, poor alignment, presence or absence of black spots and white spots, presence of various alignment defects, presence of point / line display defects Lighting inspection is performed (step 114).
Thus, the assembly of the liquid crystal cell is completed.
[0019]
【The invention's effect】
As described above, according to the present invention, since the polarizing film in which the dichroic dye is oriented in one direction is formed by printing inside the cell, the viewing angle is widened by the thickness of the glass substrate.
Further, since the polarizing film is protected by the glass substrate, it is not necessary to perform a hard coating process for preventing the polarizing plate from being scratched or an antistatic treatment for static electricity.
In addition, moisture resistance and heat resistance, which are important characteristics in expanding the use of LCDs and maintaining display quality, are improved.
[Brief description of the drawings]
FIG. 1 is a sectional view of a liquid crystal cell embodying the present invention.
FIG. 2 is a schematic diagram of a polarizing film printing apparatus.
FIG. 3 is a flowchart of a manufacturing process of a liquid crystal cell embodying the present invention.
FIG. 4 is a plan view and a cross-sectional view of a manufacturing process of a liquid crystal cell embodying the present invention.
[Explanation of symbols]
1 glass substrate 2 transparent electrode 3 SiO ₂ film 4 polarizing 5 alignment film a liquid crystal material 7 sealing member 8 spacer 11 Edition 12 print drum 13 the dispenser 14 blades 15 printing table a fine groove

Claims (4)

A liquid crystal cell comprising a polarizing film, in which dichroic dyes are oriented in a certain direction, directly or indirectly printed on the inside of the cell. A patterning step of forming a transparent electrode on the washed substrate,
An orientation treatment step of applying an orientation film to the substrate, firing and rubbing,
A substrate laminating step of scattering spacers and laminating two substrates,
A panel dividing step of dividing the bonded substrates into panels of a predetermined size,
A liquid crystal injection step of injecting a liquid crystal material into the panel;
A polarizing plate attaching process of attaching polarizing plates to both sides of the cell that has passed the panel inspection,
In the assembly process of the liquid crystal cell consisting of
A polarizing film printing / stabilizing step for stabilizing by printing and coating a polarizing film on the substrate surface before the alignment treatment step is provided,
Thus, a method for manufacturing a liquid crystal cell, wherein the step of attaching the polarizing plate is not required. In the process of forming the polarizing film,
3. The method for manufacturing a liquid crystal cell according to claim 2, wherein the pattern of the alignment film applied on the polarizing film is used as a resist and the polarizing film other than the display area is etched. In the process of forming the polarizing film,
After drying the applied polarizing film,
Method for manufacturing a liquid crystal cell according to claim 2, wherein the stabilizing polarizing film at BaCl ₂ aqueous solution (8~20wt%).

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