JP2004347989A - Manufacturing method of polarizing film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain satisfactory display characteristics of liquid crystal display by eliminating orientation unevenness appeared at the time of applying dichroic dye liquid. <P>SOLUTION: A glass plate 12 is laid on a table 1 at first, a form cylinder 4 is mounted thereon and shaft bearings 2, 2 are horizontally moved while lightly applying a brake. Then the glass plate 12 is removed and it is judged whether rubbing frequency using the same glass plate 12 has reached limit frequency or not and when limit frequency is reached, replacement with another cleaned glass plate 12 is performed. Then a substrate 7 is laid on the table 1 (step 106), ink liquid is dropped from a dispenser on the substrate 7, the form cylinder 4 is mounted on the substrate 7 and the shaft bearings 2, 2 are horizontally moved without applying the brake. Then the substrate 7 is removed and it is judged whether sheet number of the substrate 7 capable of continuously applying has reached limit sheet number or not whenever a form 6 is once rubbed. When the limit sheet number is not reached, replacement with another form cylinder 4 is performed and the process returns to the step 106. When the limit sheet number is reached, it is judged whether processing of all substrates 7 is completed or not and when the processing is not completed, replacement with another form cylinder 4 is performed and the process returns to beginning. <P>COPYRIGHT: (C)2005,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 method for manufacturing a polarizing film to which a technique of forming a polarizing film by applying a dichroic dye ink is used.
[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 has used an ink liquid containing a supramolecular complex in a liquid crystal state in which dichroic dyes developed by Optiva in the United States are spontaneously stacked in a stick shape, and this ink liquid is usually used. Has developed a technique of forming a thin film of an ink liquid by spreading it on a plate surface of a flexographic printing apparatus, and transferring and applying the ink liquid to a substrate such as glass or plastic to form a polarizing film.
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.
[0004]
The supramolecular complex composed of the dichroic dye transferred and applied from the plate to the substrate receives a shearing force and orients in a certain direction, so that the dye molecules are regularly arranged (crystallized) to produce polarization performance.
Ideally, the oriented supramolecular complex is arranged in parallel with the substrate, but in general, it generally deviates more or less from this ideal arrangement.
Supramolecular complexes originally have the property of aligning the major axis of the supramolecular complex in a specific direction, but the orientation of the supramolecular complex depends on the surface state of the substrate or plate, This is because it changes depending on the magnitude of the surface tension acting between the supramolecular composites and the action of elastic strain energy related to the arrangement of the supramolecular composites.
[0005]
Since the polarizing film plays an important role in visualizing the change in the orientation of the liquid crystal due to the electric field, the polarizing film has a large effect on the display characteristics of the LCD.
However, the effective critical surface tension changes due to the influence of moisture or gas adsorbed on the surface of the substrate or plate, or the contact of the supramolecular complex with the substrate or plate, and the magnitude of the surface tension changes. The relationship of the orientation of the molecular complex does not always hold.
In addition, the state of the elastic strain energy on the surface slightly varies depending on the substrate or plate used.
For this reason, the supramolecular composite applied to the substrate surface cannot obtain a uniform alignment, and the alignment is deviated from an ideal alignment, and uneven alignment occurs.
These alignment non-uniformities appear as defects in appearance, and degrade the display characteristics of the LCD.
[0006]
Therefore, an object of the present invention is to make it possible to obtain good LCD display characteristics by minimizing alignment unevenness that occurs when a polarizing film is formed by printing and applying a dichroic dye ink liquid. Things.
[0007]
[Means for Solving the Problems]
In order to achieve such an object, the present invention is configured as follows.
[0008]
That is, the method for producing a polarizing film according to the present invention is a method in which an ink liquid containing a liquid crystal supramolecular complex in which dichroic dyes are spontaneously stacked in a stick form is fixed to a plate cylinder that rolls on a substrate. In the step of preparing a polarizing film by spreading the above, the above object is achieved by mechanically rubbing the surface of the plate along the printing direction before applying the ink liquid to the substrate.
[0009]
Further, the method for producing a polarizing film of the present invention is characterized in that the friction is performed by sliding the plate on a glass plate.
[0010]
Further, in the method for manufacturing a polarizing film according to the present invention, after the ink liquid is applied to the substrate, the plate is replaced with another washed and dried plate to prepare for the next coating.
[0011]
Further, the method of manufacturing a polarizing film of the present invention is characterized in that the friction of the plate and the application of the substrate are repeated, and the n substrates are continuously applied for one friction.
[0012]
Further, in the method for producing a polarizing film of the present invention, a limited number of times of the friction of the plate is provided, and when the friction of the plate reaches the limited number of times, the glass plate is replaced with another washed and dried glass plate. It is characterized by preparing for the following friction.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0014]
The method for manufacturing a polarizing film according to the present invention includes a step of applying an ink liquid containing a supramolecular complex in a liquid crystal state in which dichroic dyes are spontaneously stacked in a stick shape to a substrate while applying a shearing force to the plate. Is mechanically rubbed along the printing direction to make the arrangement state of the supramolecular complex uniform when applied to a substrate, thereby reducing alignment unevenness.
[0015]
FIG. 1 shows a schematic view of a polarizing film printing apparatus embodying the present invention.
In the polarizing film printing apparatus, bearings 2 and 2 are erected on both sides of a table 1, and longitudinal grooves 3 and 3 are provided in the bearings 2 and 2 so that both ends of a shaft 5 of a plate cylinder 4 are dropped. The shaft 5 of the plate cylinder 4 is loosely fitted to the bearings 2 and 2.
The bearings 2 and 2 are configured to be horizontally movable and connected to horizontal moving means (not shown).
A plate 6 having many fine grooves a is attached to the plate cylinder 4, and a substrate 7 is placed on the table 1.
Weights 8, 8 of equal weight are attached to both sides of the shaft 5 of the plate cylinder 4, thereby adjusting the force acting between the plate 6 and the substrate 7.
Further, wheels 9, 9 integral with the shaft 5 are attached to both ends of the shaft 5 of the plate cylinder 4, and are braked so that the shaft 5 of the plate cylinder 4 is braked.
The wheels 9, 9 are formed of a material having a large coefficient of friction, and a pad is pressed against the material to suppress its rotation.
Alternatively, it is formed of an iron-based magnetic material, and its rotation is suppressed in a non-contact manner by magnetic lines of force generated by applying a current to a coil adjacent to the coil.
[0016]
The polarizing film printing apparatus embodying the present invention has the above-described configuration. When applying a polarizing film, as shown in FIG. (Step 101).
Next, the plate cylinder 4 is placed on the glass plate 12, and the bearings 2 and 2 are horizontally moved while lightly applying a brake (Step 102).
At this time, the plate cylinder 4 rolls while slipping on the glass plate 12 to slide the plate 6 and rub the surface of the plate 6 to a very small extent.
Thereby, a directional flaw corresponding to the size of the supramolecular complex contained in the ink liquid can be formed on the surface of the plate 6.
Next, the glass plate 12 is removed from above the table 1 by the robot arm 10 and returned to the original storage stage 11 (step 103).
Next, it is determined whether or not the number of times of rubbing using the same glass plate 12 has reached the limit number (step 104). If the number has been reached, the glass plate 12 is replaced with another cleaned glass plate 12 (step 104). Step 105).
[0017]
Next, the substrate 7 is pulled out from the substrate cassette 13 by the robot arm 10 and placed on the table 1 (step 106).
Next, an ink solution is dropped onto the substrate 7 from an injection needle-shaped or wide slit-shaped dispenser (not shown), the plate cylinder 4 is placed on the substrate 7, and the bearings 2 and 2 are moved horizontally without applying a brake. (Step 107).
As a result, the plate cylinder 4 rolls on the substrate 7 and spreads the ink liquid with the plate 6 to form a thin film of the ink liquid on the surface of the substrate 7.
At this time, a shear force is applied to the supramolecular complex contained in the ink liquid in a small gap between the fine groove a of the plate 6 and the substrate 7, and at the same time, the direction is given by the scratches on the surface of the plate 6, The molecular complexes are oriented in a certain direction and aligned on the substrate 7.
Therefore, the thin film of the ink liquid formed on the substrate 7 has polarization performance.
Next, the substrate 7 is removed from above the table 1 by the robot arm 10 and stored in another substrate cassette 13 or the same substrate cassette 13 (step 108).
[0018]
Next, each time the plate 6 is rubbed once, it is determined whether or not the number of substrates 7 that can be continuously applied has reached the limit number (step 109). If not, the plate cylinder 4 is moved from the bearings 2, 2. The plate is removed, replaced with another plate cylinder 4 having the washed and dried plate 6, and the process returns to step 106 (step 110).
A plurality of plates 6 and plate cylinders 4 are prepared, and the replaced plates 6 and plate cylinders 4 are washed and dried off-line, and wait for the next replacement.
As a result, the tact time can be reduced, and the device can be simplified.
If the number has reached the limit, it is next determined whether or not the processing of all the substrates 7 has been completed (step 111). If the processing has not been completed, the plate cylinder 4 is similarly removed from the bearings 2, 2. Then, the plate is replaced with another plate cylinder 4 having the washed and dried plate 6, and the process returns to step 101 (step 112). Otherwise, the process ends.
[0019]
Each time the plate is rubbed and applied, the orientation quality of the plate is maintained at the highest level, but the plate will be damaged.
Therefore, once the plate is rubbed once, a plurality of substrates are successively applied. However, the number of substrates that can be continuously applied is limited to five.
Therefore, the number of sheets to be continuously coated is preferably set to 5, so that the alignment quality of the plate can be kept within a required level.
Further, the number of times that the same glass plate can be rubbed is limited to 30 times, and it is preferable to replace the glass plate with another washed and dried glass plate when the friction is repeated 30 times.
[0020]
Once used, wash the plate with different chemicals depending on the material of the plate.
For example, in the case of a plate made of butadiene or urethane-based photosensitive resin, it is preferable that the plate is washed with an alkali, then washed with a mixed solution of permanganic acid, rinsed, and drained.
At this time, it is preferable that the wiping coefficient is large with the wire cloth. If the friction coefficient is small, the washing method becomes insufficient.
When changing the material of the plate, it is preferable to change the alkali used first according to the material to another appropriate chemical.
[0021]
A similar alignment film can be obtained by using a rubber roll having a large number of fine grooves instead of the plate.
In this case, it is preferable to wash the friction glass plate with a mixed solution of MEK (methyl ethyl ketone) and toluene.
After that, the same treatment may be performed with potassium permanganate.
[0022]
【The invention's effect】
As described above, according to the present invention, before applying the ink liquid to the substrate, the surface of the plate is rubbed to give directionality, so that the supramolecular complex on the surface in contact with the plate is oriented in a certain direction. Align on the substrate.
As a result, the arrangement state of the supramolecular complex can be changed to a uniform molecular arrangement state to reduce alignment unevenness.
Therefore, it becomes possible to stably produce an LCD having excellent display characteristics.
[Brief description of the drawings]
FIG. 1 is a schematic view of a polarizing film printing apparatus embodying the present invention.
FIG. 2 is a flowchart of a method for manufacturing a polarizing film embodying the present invention.
[Explanation of symbols]
1 Table 2 Bearing 3 Groove 4 Plate cylinder 5 Axis 6 Plate 7 Substrate 8 Weight 9 Wheel 10 Robot arm 11 Storage stage 12 Glass plate 13 Substrate cassette a Micro groove

Claims (5)

In a process of forming a polarizing film by spreading an ink liquid containing a supramolecular complex in a liquid crystal state in which dichroic dyes are spontaneously stacked in a stick form on a plate stopped on a plate cylinder that rolls on a substrate,
A method for manufacturing a polarizing film, wherein the surface of the plate is mechanically rubbed along a printing direction before applying the ink liquid to a substrate. The method according to claim 1, wherein the friction is performed by sliding the plate on a glass plate. After applying the ink liquid to the substrate,
2. The method for producing a polarizing film according to claim 1, wherein the plate is replaced with another washed and dried plate to prepare for the next coating. Repeat the friction of the plate and the application of the substrate,
2. The method for manufacturing a polarizing film according to claim 1, wherein n substrates are continuously applied for one friction. Set a limited number of times for the friction of the plate,
When the plate friction reaches the limit,
The method according to claim 1, wherein the glass plate is replaced with another washed and dried glass plate to prepare for the next friction.

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