JP2010054753A - Method of manufacturing liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a liquid crystal display device capable of reducing the performance degradation of the liquid crystal display device, facilitating process management and improving contrast. <P>SOLUTION: The method of manufacturing the liquid crystal display device includes: a liquid crystal polymer application processes 130, 140 for containing a liquid crystal polymer component in at least one component, providing the liquid crystal polymer component with a UV curing functional component, and applying a block polymer dissolved in a solvent, to a TFT substrate 10 and a CF substrate 20 so that the liquid crystal polymer component is on the opposite side to the substrates; a seal application process 160 for applying a sealant to the CF substrate 20 to surround a region into which liquid crystal is put; a liquid crystal drip injection process 170 for filling liquid crystal between the TFT substrate 10 and CF substrate 20; a heating/magnetic field aligning process 180 for heating at a temperature not lower than a glass transition point of the liquid crystal polymer component for a predetermined time and applying a magnetic field in a direction to align the liquid crystal; and a UV curing process 190 for irradiating UV (ultraviolet rays) between the substrates to UV-cure the block polymer and to fix the alignment. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a liquid crystal display device that achieves uniform alignment by a non-contact method by performing magnetic field alignment using a block polymer containing a liquid crystalline polymer component as at least one component as an alignment film. is there.

  A method for manufacturing a conventional liquid crystal display device will be described with reference to FIGS. FIG. 5 is a diagram showing the steps of a conventional method for manufacturing a liquid crystal display device. FIG. 6 is a diagram showing a rubbing step of a conventional method for manufacturing a liquid crystal display device.

  In FIG. 5, the upper step 910A to step 950 and the lower step 910B to step 960 may process the upper step and the lower step simultaneously, or after the upper step or the lower step, the lower step or the upper step. The process may be processed.

  In the cleaning process 910A, the TFT substrate 10 that has completed the TFT (Thin Film Transistor) array process is first cleaned when it is put into the cell process.

  In the cleaning process 910B, the CF substrate 20 that has completed the CF (Color Filter) generation process is first cleaned when it is put into the cell process.

  Next, the alignment film forming steps 920A and 920B include three steps: a printing step, a pre-baking step, and a main curing step.

  In the printing process, an alignment film (polyimide dissolved in a solvent) is applied to the TFT substrate 10 and the CF substrate 20 by a flexographic printing method or the like to form an alignment film.

  In the pre-baking step, heating is performed at about 60 to 100 ° C. for several minutes in order to remove the solvent from the printed alignment film. Most are hot plate type or oven type.

  In the main curing step, heating is performed at several hundred and several tens of degrees Celsius for the final polymerization.

  Next, in the rubbing process 930A, 930B, in order to determine the alignment direction (orientation direction) of the liquid crystal, as shown in FIG. 6, a roller 92 around which a cloth (buff material) 93 such as cotton or rayon is wound is used. The surfaces of the alignment films 91 formed on the substrate 10 and the CF substrate 20 are rubbed.

  Next, in the cleaning processes 940A and 940B, the hair of the cloth and the scraps of the alignment film generated in the rubbing process are washed away.

  Next, in a conductive material application step 950, a conductive material such as an Ag paste is applied to the TFT substrate 10 in a dot shape in order to establish conduction between the TFT substrate 10 and the CF substrate 20. Note that this is not necessary in the IPS mode.

  In a seal application step 960, a sealant is applied to the CF substrate 20 so as to surround the region where the liquid crystal enters. The sealing agent also plays a role of bonding the TFT substrate 10 and the CF substrate 20 together. After applying the sealing agent, pre-baking may be performed at about 90 ° C. for several minutes. There are a thermosetting type and a UV (ultraviolet ray) curing type, but when liquid crystal dropping injection is performed, a UV curing type sealing agent is often used.

  Next, the liquid crystal dropping / injecting step 970 includes two steps, a liquid crystal dropping step and an overlaying step.

  In the liquid crystal dropping step, a required amount of liquid crystal is dropped on the CF substrate 20.

  In the superposition process, the CF substrate 20 onto which the liquid crystal is dropped and the TFT substrate 10 are precisely superposed under vacuum. After the superposition, the substrate is taken out into the atmosphere, and is crushed to the target cell GAP at atmospheric pressure. Thereafter, the sealant is semi-cured by irradiating the sealant with ultraviolet rays (UV).

  Next, in the heating step 980, heating is carried out for several tens of minutes at about 150 ° C., the sealant is fully cured, and the alignment stability is enhanced by reorienting the liquid crystal from the isotropic phase to the liquid crystal phase.

  As a related prior art document, Patent Document 1, which describes a manufacturing method of a liquid crystal display device in which a liquid crystal polymer that is not a block polymer is used as an alignment film and a magnetic field is applied in a state where the liquid crystal is not filled, is a block copolymer There is Patent Document 2 in which is described.

Japanese Patent Publication No. 7-54381 JP 2004-124088 A

  In the conventional method for manufacturing a liquid crystal display device as described above, defects (rubbing scratches, defective foreign matter, etc.) due to the rubbing processes 930A and 930B occur, and the performance of the liquid crystal display device is degraded. Further, the rubbing processes 930A and 930B have a problem that process control is difficult because it is difficult to quantify the control factors. Further, there is a problem that the alignment axis is deviated due to rubbing scratches, rubbing direction misalignment, and misalignment when the TFT substrate 10 and the CF substrate 20 are overlapped, and the contrast of the liquid crystal display device is lowered.

  The present invention has been made to solve the above-described problems, and its object is to reduce the deterioration of the performance of the liquid crystal display device, to facilitate process management, and to improve the contrast of the liquid crystal display device. A method of manufacturing a liquid crystal display device that can be obtained is obtained.

  The method for producing a liquid crystal display device according to the present invention comprises a liquid crystalline polymer component as at least one component, a UV curing functional component in the liquid crystalline polymer component, and a block polymer dissolved in a solvent, the liquid crystalline polymer A liquid crystal polymer coating step for applying to the array substrate and the color filter substrate so that the component is on the opposite side of the substrate, and a seal coating step for applying a sealing agent to the color filter substrate so as to surround the region where the liquid crystal enters And liquid crystal forming step of filling and forming liquid crystal between the array substrate and the color filter substrate, and heating for a predetermined time at a first predetermined temperature not lower than the glass transition point of the liquid crystalline polymer component to align the liquid crystal Heating and magnetic field orientation process that applies a magnetic field in the direction, UV irradiation between the substrates and UV curing of the block polymer to fix the orientation That is provided with a a UV curing step.

  The method for manufacturing a liquid crystal display device according to the present invention has the effects that it is possible to reduce deterioration in the performance of the liquid crystal display device, facilitate process management, and improve the contrast of the liquid crystal display device.

Embodiment 1 FIG.
A method of manufacturing the liquid crystal display device according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing steps of a method for manufacturing a liquid crystal display device according to Embodiment 1 of the present invention. In addition, in each figure, the same code | symbol shows the same or equivalent part.

  In FIG. 1, the manufacturing method of the liquid crystal display device according to Embodiment 1 of the present invention includes a cleaning process 110, a cleaning process 120, a liquid crystal polymer coating process 130, a liquid crystal polymer coating process 140, and a conductive material coating. A step 150, a seal coating step 160, a liquid crystal dropping injection step 170, a heating / magnetic field alignment step 180, and a UV curing step 190 are provided.

  Next, the operation of each process of the manufacturing method of the liquid crystal display device according to the first embodiment will be described with reference to the drawings.

  FIG. 2 is a diagram showing a liquid crystal polymer coating step in the method of manufacturing the liquid crystal display device according to Embodiment 1 of the present invention. FIG. 3 is a diagram showing a heating / magnetic field alignment step and a UV curing step in the method for manufacturing the liquid crystal display device according to Embodiment 1 of the present invention.

  In FIG. 1, the upper step 110 to the step 150 and the lower step 120 to the step 160 may process the upper step and the lower step simultaneously, or after the upper step or the lower step, the lower step or the upper step. The process may be processed.

  In the cleaning process 110, the TFT substrate (array substrate) 10 that has completed the TFT (Thin Film Transistor) array process is first cleaned when it is put into the cell process.

  In the cleaning process 120, the CF substrate (color filter substrate) 20 that has completed the CF (Color Filter) generation process is first cleaned when it is put into the cell process.

  Next, the liquid crystal polymer coating steps 130 and 140 are composed of three steps: a coating step, a pre-baking step, and a main curing step.

  In the coating step, instead of the alignment film, a liquid crystalline polymer dissolved in a solvent (a block polymer in which a liquid crystalline polymer component has a UV curing function component) is applied to the TFT substrate 10 and the CF substrate 20 to form. .

  As shown in FIG. 2A, a block polymer 1 containing a liquid crystalline polymer component as at least one component is used. Further, as shown in FIG. 2B, the block polymer 1 and the substrate surface are designed so that the liquid crystalline polymer component faces the side opposite to the substrates 10 and 20 (liquid crystal side).

  As shown in FIGS. 2 (c) and 2 (d), the component (liquid crystalline polymer component) 1a for aligning the liquid crystal faces upward, that is, faces the side opposite to the substrates 10 and 20 (liquid crystal side). . If necessary, the liquid crystalline polymer component 1a is raised by applying to the substrates 10 and 20 a substance (interface adjustment film) 2 that is compatible with the components 1b and 1c different from the component 1a for aligning the liquid crystal. Realize facing. FIG. 2 (e) shows an example in which the component (liquid crystalline polymer component) 1a for aligning the liquid crystal does not face upward.

  In the pre-baking step, heating is performed at about 60 to 100 ° C. for several minutes in order to remove the solvent from the applied liquid crystalline polymer (block polymer in which the liquid crystalline polymer component has a UV curing function component). Most are hot plate type or oven type.

  In the main curing step, heating is performed at several hundreds of degrees Celsius for several tens of degrees in order to improve the adhesion between the block polymer 1 and the glass substrate.

  Next, in the conductive material application process 150, a conductive material such as an Ag paste is applied to the TFT substrate 10 in a dot shape in order to establish conduction between the TFT substrate 10 and the CF substrate 20. Note that this is not necessary in the IPS mode.

  In the seal application process 160, a sealant is applied to the CF substrate 20 so as to surround the region where the liquid crystal enters. The sealing agent also plays a role of bonding the TFT substrate 10 and the CF substrate 20 together. After applying the sealing agent, pre-baking may be performed at about 90 ° C. for several minutes. There are a thermosetting type and a UV (ultraviolet ray) curing type, but when performing liquid crystal drop injection, a UV curing type sealing agent is used.

  Next, the liquid crystal dropping / injecting step 170 includes two steps of a liquid crystal dropping step and an overlaying step.

  In the liquid crystal dropping step, a required amount of liquid crystal is dropped on the CF substrate 20.

  In the superposition process, the CF substrate 20 onto which the liquid crystal is dropped and the TFT substrate 10 are precisely superposed under vacuum. After the superposition, the substrate is taken out into the atmosphere, and is crushed to the target cell GAP at atmospheric pressure. Thereafter, the sealant is semi-cured by irradiating the sealant with ultraviolet rays (UV).

  Next, in the heating / magnetic field alignment step 180, heating is performed at about 150 ° C. for several tens of minutes, the sealant is fully cured, and the liquid crystal is applied in the direction in which the liquid crystal is to be aligned. Realize orientation.

  As shown in FIG. 3 (a), after the liquid crystal 3 is filled, the liquid crystalline polymer component is heated to a temperature equal to or higher than the glass transition point Tg, for example, at 150 ° C. for 30 minutes, and cooled to room temperature at 1 ° C./min. From the start of heating to the end of cooling, the orientation treatment is performed by applying a magnetic field of 5T (Tessler), for example, with a permanent magnet or a superconducting magnet. That is, a magnetic field is applied while cooling from a temperature higher than the glass transition point Tg of the liquid crystalline polymer component to a temperature lower than the glass transition point Tg and the liquid crystal transition point NI. The magnetic field is continuously applied from a temperature higher than the glass transition point Tg to a temperature lower than the glass transition point Tg and the liquid crystal transition point NI. Note that the magnetic field may be applied in a state where the liquid crystal is not filled.

  Next, in the UV curing process 190, when the uniform alignment is obtained, the liquid crystal polymer (block polymer) is UV cured and fixed in alignment by irradiating ultraviolet rays (UV) between the substrates 10 and 20. Turn into.

  As shown in FIG. 3B, the block polymer is provided with a UV curing functional component, and after obtaining a uniform orientation by magnetic field orientation, for example, irradiation with ultraviolet rays (UV) of several hundred to tens of thousands mJ (millijoule) is performed. Then, UV-curing improves alignment stability. This UV irradiation is performed at a temperature lower than the glass transition point Tg of the liquid crystalline polymer component and the transition point NI of the liquid crystal to fix the alignment. The UV irradiation may be performed in a state where no magnetic field is applied, but the alignment becomes more uniform when performed while the magnetic field is applied.

  FIG. 4 is a diagram showing another process of the method of manufacturing the liquid crystal display device according to Embodiment 1 of the present invention.

  4, the manufacturing method of the liquid crystal display device according to the first embodiment of the present invention includes a cleaning process 110, a cleaning process 120, a liquid crystal polymer coating process 130, a liquid crystal polymer coating process 140, and a conductive material coating. A step 150, a seal coating step 160, a heating / magnetic field orientation step 180, and a UV curing step 190 are provided. Further, instead of the liquid crystal dropping injection step 170, a bonding step 210, a heating / crimping step 220, A glass cutting step 230, a liquid crystal injection step 240, and a sealing step 250 are provided.

  The outline of the bonding process 210 to the sealing process 250 is as follows.

  After the seal coating process 160, the CF substrate 20 is placed on the TFT substrate 10 and bonded thereto. Heat is applied while applying pressure to harden the sealant. Thereafter, the mother glass substrate is cut into liquid crystal cell (panel) units or strips. Subsequently, the two glass substrates of the liquid crystal cell are kept in vacuum, and liquid crystal is injected from the injection port by utilizing capillary action. When the liquid crystal injection is completed, the injection port is closed (sealing).

  According to the manufacturing method of the liquid crystal display device according to the first embodiment of the present invention, since the alignment process is performed by a magnetic field, that is, non-contact alignment, there is no damage due to rubbing, and the contrast and yield can be improved. it can. In order to perform alignment treatment by heating and applying a magnetic field after filling the liquid crystal, that is, by eliminating the rubbing steps 930A and 930B, by eliminating the cleaning steps 940A and 940B after rubbing, and simultaneously performing annealing and magnetic field alignment after liquid crystal drop injection. The overall process TAT (Turn Around Time) can be shortened and the cost can be reduced. In addition, since the alignment treatment is performed after filling the liquid crystal, there is no alignment axis shift (rubbing direction shift or overlap shift) seen in the rubbing steps 930A and 930B, and contrast can be improved. Furthermore, the magnetic field orientation can be managed by controllable factors such as magnetic field strength, temperature, time, parallelism, and angle.

It is a figure which shows the process of the manufacturing method of the liquid crystal display device which concerns on Embodiment 1 of this invention. It is a figure which shows the liquid crystal polymer application | coating process of the manufacturing method of the liquid crystal display device which concerns on Embodiment 1 of this invention. It is a figure which shows the heating and magnetic field orientation process and UV hardening process of the manufacturing method of the liquid crystal display device which concerns on Embodiment 1 of this invention. It is a figure which shows another process of the manufacturing method of the liquid crystal display device which concerns on Embodiment 1 of this invention. It is a figure which shows the process of the manufacturing method of the conventional liquid crystal display device. It is a figure which shows the rubbing process of the manufacturing method of the conventional liquid crystal display device.

Explanation of symbols

  1 block polymer, 1a liquid crystalline polymer component, 10 TFT substrate, 20 CF substrate, 110 cleaning process, 120 cleaning process, 130 liquid crystal polymer coating process, 140 liquid crystal polymer coating process, 150 conductive material coating process, 160 seal coating process , 170 liquid crystal injection step, 180 heating / magnetic field alignment step, 190 UV curing step, 210 bonding step, 220 heating / compression step, 230 glass cutting step, 240 liquid crystal injection step, 250 sealing step.

Claims (6)

A liquid crystal polymer component is included in at least one component, and this liquid crystal polymer component has a UV curing functional component, and a block polymer dissolved in a solvent is disposed so that the liquid crystal polymer component is opposite to the substrate. A liquid crystal polymer coating step for coating the array substrate and the color filter substrate;
A seal application step of applying a sealant to the color filter substrate in order to surround an area where liquid crystal enters;
A liquid crystal forming step of filling and forming liquid crystal between the array substrate and the color filter substrate;
Heating and magnetic field orientation step of heating for a predetermined time at a first predetermined temperature not lower than the glass transition point of the liquid crystalline polymer component and applying a magnetic field in the direction in which the liquid crystal is to be aligned;
And a UV curing step of fixing the orientation by irradiating ultraviolet rays between the substrates to UV cure the block polymer. The method for manufacturing a liquid crystal display device according to claim 1, further comprising a cleaning step of cleaning the array substrate and the color filter substrate before the liquid crystal polymer coating step. The liquid crystal polymer coating step includes
An application step of applying the block polymer to the array substrate and the color filter substrate;
A pre-baking step of heating at a second predetermined temperature for several minutes in order to remove the solvent from the applied block polymer;
The method of manufacturing a liquid crystal display device according to claim 1, further comprising: a main curing step of heating for several tens of minutes at a third predetermined temperature in order to improve adhesion between the block polymer and the glass substrate. 2. The liquid crystal according to claim 1, further comprising a conductive material applying step of applying a conductive material to the array substrate in order to establish conduction between the array substrate and the color filter substrate after the liquid crystal polymer applying step. Manufacturing method of display device. The liquid crystal forming step is a liquid crystal dropping injection step,
A liquid crystal dropping step of dropping a required amount of liquid crystal on the color filter substrate;
The method for manufacturing a liquid crystal display device according to claim 1, further comprising an overlaying step of overlaying the color filter substrate onto which the liquid crystal is dropped and the array substrate under vacuum. The liquid crystal forming process includes:
A bonding step of attaching the color filter substrate on the array substrate and bonding them together,
A heating and pressure bonding process in which heat is applied while applying pressure to harden the sealant;
A glass cutting step of cutting the mother glass substrate into liquid crystal cell units;
A liquid crystal injecting step of injecting liquid crystal from the inlet using capillary action while keeping the two glass substrates of the liquid crystal cell in a vacuum;
The method for manufacturing a liquid crystal display device according to claim 1, further comprising: a sealing step of closing the injection port when the liquid crystal injection is completed.

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