KR100355395B1 - Method for fabricating liquid crystal display and apparatus used therefor - Google Patents

Abstract

PURPOSE: A method for fabricating a liquid crystal display and an apparatus used for fabricating the liquid crystal display are provided to fabricate a liquid crystal display having a uniform cell gap and a good pixel arrangement. CONSTITUTION: An apparatus for controlling the thickness of a liquid crystal display includes a substrate pressing part(22), an ultraviolet lamp(24), and a hole(23). The substrate pressing part presses upper and lower substrates of the liquid crystal display into a predetermined thickness. The ultraviolet lamp set inside the substrate pressing part and hardens ultraviolet-hardening resin used for sealing, coated between the upper and lower substrates. The ultraviolet lamp is set in the hole formed in the substrate pressing unit.

Description

Method for manufacturing liquid crystal display device and apparatus used therein

The present invention relates to a method for manufacturing a liquid crystal display device and an apparatus used therein, and more particularly, to a method for manufacturing a liquid crystal display device and an apparatus used therein, which can realize an excellent image by electro-optical operation with a uniform cell thickness. It is about.

Currently used image display devices include a cathode ray tube (CRT), a liquid crystal display device (LCD), a plasma display device (PDP), and a fluorescent display device (VFD).

Among the image display devices, the cathode ray tube has superior performance to other devices in terms of image quality and brightness. However, there is a disadvantage that the volume is too large and the weight is too heavy to be applied to the current trend of becoming larger.

On the other hand, in the field of image display devices, flat panel display devices are widely used in various fields because they can be significantly reduced in terms of volume and weight and have low power consumption.

In particular, since liquid crystals are easy to handle and have inherent characteristics in which crystallinity changes depending on whether or not an external electric field is used, liquid crystal display elements using liquid crystals are most widely used as materials for display elements.

1 is a perspective view of a general liquid crystal display device. In general, a conventional liquid crystal display device forms ITO (Indium Tin Oxide) electrodes 13 and 19 on two substrates 11 and 11 ', and then joins an ITO substrate while forming a cell gap with a spacer. Then, it is formed by the method of injecting the liquid crystal 15.

In the liquid crystal display device, the basic driving principle is that the arrangement of the liquid crystals is changed by the influence of the electric field depending on whether the external voltage is applied, and the liquid crystal that blocks and transmits external light flowing into the liquid crystal display device according to the change of the arrangement. Is to use the inherent characteristics of That is, when a voltage is applied to the lower ITO electrode 13 and the upper ITO electrode 19 in FIG. 1, an electric field is formed in the liquid crystal layer 15. In addition, the electric field formed in the liquid crystal layer drives the liquid crystal in a predetermined direction, and light flowing into the liquid crystal layer of the display device is blocked or transmitted according to whether the liquid crystal is driven.

Therefore, the transmission and blocking characteristics of the liquid crystal display device used as the image display device are affected by the driving characteristics of the liquid crystal, and the driving characteristics of the liquid crystal are the exact thickness of the liquid crystal cell gap and the liquid crystal cell formed inside the liquid crystal display element. The uniformity of the gap thickness is affected. Therefore, if the liquid crystal cell gap is unevenly formed during the manufacturing of the display device, the driving characteristics of the liquid crystal are not good and the performance of the liquid crystal display device is degraded.

However, in the conventional process of contacting the upper and lower substrates for the arrangement of the upper and lower substrates, after applying the UV-curable resin to the four corners of the substrate, by irradiating with ultraviolet rays to fabricate an incompletely primary bonded panel, It was common practice to move the first bonded panel back to the thermosetting device to completely bond the panel. Through such a multi-step curing process, not only the cell thickness is uneven during the movement but also the positional arrangement of the pixels formed on the substrate is disturbed.

In addition, in the conventional apparatus for manufacturing a panel by contacting the upper and lower substrates, the cell gap thickness during the cell gap formation process due to the non-equilibrium state of the upper and lower substrate crimping portions, which are parts that can directly satisfy the cell thickness control. There was also a problem of becoming uneven.

Accordingly, an object of the present invention is to provide a thickness adjusting apparatus for manufacturing a liquid crystal display device having a uniform cell gap thickness and a good position arrangement state of pixels by solving the above problems.

In the present invention to achieve the above object,

A substrate pressing part for pressing the upper substrate and the lower substrate of the liquid crystal display device to a predetermined thickness;

Resin curing apparatus for sealing is mounted in the substrate pressing portion for curing the resin for sealing between the upper and lower substrates: And

The thickness adjusting device of the liquid crystal display device is provided in the substrate crimping portion and includes a mounting hole for mounting the sealing curing device.

Another object of the present invention is to provide a method for simply manufacturing a liquid crystal display device having a uniform cell gap thickness and having a good positional arrangement of pixels.

Another object of the present invention,

Applying a sealant to the edge of the substrate coated with the ITO electrode;

Dispersing the spacer on another substrate coated with the ITO electrode: and

In the method of manufacturing a liquid crystal display device comprising the step of overlapping the two substrates prepared in the step so that the pixels are located in a predetermined position and curing the sealant,

The sealant is a thermosetting resin,

Curing of the sealant is achieved by a method of manufacturing a liquid crystal display device, characterized in that the two substrates are placed in a thickness control device and heated under a constant pressure.

Another object of the present invention,

Applying a sealant to the edge of the substrate coated with the ITO electrode:

Dispersing the spacer on another substrate coated with the ITO electrode: and

In the method of manufacturing a liquid crystal display device comprising the step of overlapping the two substrates prepared in the step so that the pixels are located in a predetermined position and curing the sealant,

The sealant is an ultraviolet curable resin,

Curing of the sealant is also achieved by a method of manufacturing a liquid crystal display device, characterized in that by placing the two overlapping substrates in a thickness control device and irradiating ultraviolet rays under a constant pressure.

According to the present invention, in the process of contacting the upper and lower substrates, the sealing agent is cured by a one-step process without undergoing a multi-step curing process. Characterized in that it can be maintained.

To this end, an apparatus for curing the sealant is mounted in the substrate pressing portion of the thickness adjusting device of the present invention, and a hole is formed in the substrate pressing portion for mounting the sealing agent curing apparatus. That is, according to the case where the sealing agent used is an ultraviolet curable resin or a thermosetting resin, respectively, a sealing agent can be hardened by a one-step process by selectively mounting and using an ultraviolet irradiation device or a heating device in a hole.

In addition, in the present invention, the equilibrium induction apparatus may be additionally mounted to the substrate pressing portion. That is, when pressure is applied to the upper and lower substrates, it can be adjusted to form a cell gap having a uniform thickness as a whole through the balance induction apparatus.

2 shows a thickness adjusting device of a liquid crystal display device to form a cell gap of a predetermined thickness according to an embodiment of the present invention. As can be seen from the figure, the apparatus of the present invention is equipped with an ultraviolet lamp 24 and an ultraviolet lamp mounting hole 23 for mounting the ultraviolet lamp 24 in the substrate pressing part 2, and the equilibrium induction apparatus ( 29).

Therefore, when the equilibrium induction device 29 of the apparatus of the present invention is used, the upper and lower substrate crimps 22 are balanced while the upper substrate 25 and the lower substrate 28 are compressed to have a uniform thickness. The cell gap can be formed. In addition, since the ultraviolet curable resin is cured by the ultraviolet lamp 24 in the compressed state, the cell gap uniformly formed can be fixed as it is. In this process, the positions of the first arranged pixels are maintained almost unchanged. In addition, when using thermosetting resin as a sealing agent, the said ultraviolet lamp can be replaced with a heater and can be used.

In particular, it is possible to mount the rubber plate 30 that is soft and has good light transmittance on the pressing surface of the substrate pressing portion. That is, by installing a rubber plate on the substrate crimping unit, it is possible to minimize the variation in cell gap thickness and the possibility of pixel array variation due to mechanical misalignment during the crimping. Suitable rubber components for such use include urethane rubber, silicone rubber, and the like, but are not necessarily limited thereto.

In the present invention, as a substrate crimping material, quartz, which is transparent, has good light transmittance and has strong strength, is used. Since quartz is transparent, the irradiated ultraviolet ray can be reached without reaching the target. Therefore, the substrate crimp made of quartz may also be used in a process of manufacturing a polymer liquid crystal composite display device.

In addition, quartz has a small thermal expansion coefficient and high strength to withstand external pressure, so it is not only suitable for use as a material for adjusting cell thickness but also easy to process precisely so that the entire surface can be pressed with the same force when adjusting cell thickness. have.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not necessarily limited thereto.

<Example 1>

On the glass substrate coated with two transparent electrodes, a substrate on which 10 micrometers of micropearl (Mitsui Toatsu Corporation) was dispersed as a spacer and another substrate seal-printed with 3025B (UV curing sealant) were used. It was placed on the thickness control ultraviolet irradiation device of the present invention and pressed for 30 minutes under a vacuum of 12 psi and a pressure of 1, 2 kg / cm 2. Subsequently, ultraviolet rays were irradiated with an ultraviolet lamp under the same pressing condition to make a panel having a desired empty cell. As a result of measuring the thickness of the blank cell thus prepared by a thickness gauge, the thickness of the cell was uniform throughout, and the average value of 10 points was 10.l5 μm. In addition, the pixel position arrangement state between the upper and lower substrates also maintained the state before ultraviolet curing.

In a separate container, TL205 (Merck, liquid crystal substituted with fluorine group) and BL001 (Merck, liquid substituted with cyan group) were mixed, and then PN393 (Merck, photocurable composition containing a polymerization initiator) was added thereto. It put and mixed, and obtained the single-phase liquid crystal composition which has the following composition ratio.

The obtained liquid crystal composition was injected into a blank cell of the panel prepared above in an isotropic liquid state at 20 ° C., and then irradiated for 90 seconds with a 365 nm ultraviolet lamp to phase separate into a liquid crystal and a polymer state to form a liquid crystal / polymer resin composite film. The composite film thus obtained had a driving voltage of 4.5V, a contrast of 320: 1, a response time of 78ms, and a hysteresis of 0.47V.

<Example 2>

A panel was manufactured in the same manner as in Example 1, except that the size of the spacer was 7 µm. As a result of measuring the thickness of the empty cell with a thickness gauge, the average measured value was 7.2 μm, and the positional arrangement state of the pixels between the upper and lower substrates maintained the optimum state before UV curing. Subsequently, a composite film was manufactured in the same manner as in Example 1, with a driving voltage of 3.5V, a contrast of 108: 1, a response speed of 69ms, and a hysteresis of 0.57V.

Comparative Example 1

On a glass substrate coated with two transparent electrodes, a substrate in which 10 micrometers of micropearl (Mitsui Toatsusa) is dispersed as a spacer and another substrate printed with XN-5A-C (copper curing yarn, thermosetting sealant) are frozen. Primary precontact was made in the liner. Then using a vacuum thermocompressor for 30 minutes at 150 ℃, 12psi vacuum, 1kg / ㎠ pressure state to prepare a panel having a blank cell. As a result of measuring the thickness of the blank cell thus prepared by a thickness gauge, the thickness of the entire cell was uneven, and the average value of 10 points was 10.78 µm. In addition, the pixel position arrangement state between the upper and lower substrates is more disturbed than the state before the ultraviolet curing.

In a separate container, TL205 (Merck, liquid crystal substituted with fluorine group) and BL001 (Merck, liquid substituted with cyan group) were mixed, and then PN393 (Merck, photocurable composition containing a polymerization initiator) was added thereto. It put and mixed, and obtained the single-phase liquid crystal composition which has the following composition ratio.

The obtained liquid crystal composition was injected into a blank cell of the panel prepared above in an isotropic liquid state at 20 ° C., and then irradiated for 90 seconds with a 365 nm ultraviolet lamp to phase separate into a liquid crystal and a polymer state to form a liquid crystal / polymer resin composite film. The composite film thus obtained had a driving voltage of 5.2V, a contrast of 340: 1, a response time of 78ms, and a hysteresis of 0.54V.

Comparing Comparative Example 1 with Example 1, the composite film of the liquid crystal prepared according to the present invention has an advantage that the driving voltage is low, the response speed is fast, and the hysteresis is low, which is suitable for a dynamic screen.

Comparative Example 2

A panel was manufactured in the same manner as in Example 1, except that the size of the spacer was 7 µm. As a result of measuring the thickness of the empty cell with a thickness gauge, the average measured value was 8.06 µm, and the positional arrangement of the pixels between the upper and lower substrates was more disturbed than the ultraviolet state. Subsequently, a composite film was manufactured in the same manner as in Comparative Example 1, with a driving voltage of 4.0V, a contrast of 128: 1, a response speed of 62ms, and a hysteresis of 0.75V.

Comparing the Comparative Example 2 with Example 2, the composite film of the liquid crystal prepared by the present invention has the advantage that the driving voltage is low, the response speed is fast, and the hysteresis is suitable for the dynamic screen.

As can be seen from the above, by using the apparatus of the present invention for manufacturing a liquid crystal display device, not only can the cell gap thickness be uniformly formed, but also hundreds of thousands of pixels can be accurately arranged. Therefore, the liquid crystal display device manufactured by the method of the present invention has a good dynamic screen characteristic capable of realizing a display by electro-optical manipulation, and its manufacturing process is also simple, so that a cost reduction and a yield increase effect can be expected.

1 is a perspective view of a general liquid crystal display device.

2 is a schematic diagram showing a thickness adjusting device of a liquid crystal display device to form a cell gap of a predetermined thickness according to an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

11. Lower substrate 11 '. Upper substrate

13. Lower electrode 19. Upper electrode

14,14 ', liquid crystal aligning layer 15. liquid crystal

21. Pressure regulating device 22. Substrate crimp

23. UV lamp mounting hole 24. UV lamp

25, 28. Substrate 26. Spacer

29. Balance induction device 30. Flexible transparent rubber sheet

Claims (7)

A substrate pressing part for pressing the upper substrate and the lower substrate of the liquid crystal display device to a predetermined thickness; An ultraviolet irradiation device mounted in the substrate crimping unit to cure an ultraviolet curable resin for sealing between upper and lower substrates; And And a mounting hole formed in the substrate pressing part to mount the ultraviolet irradiation device. The apparatus of claim 1, wherein a balance induction device is mounted to the substrate crimping unit. The thickness adjusting device of the liquid crystal display device according to claim 1, wherein the upper and lower substrate contact surfaces of the substrate crimping portion are provided with a rubber plate having a soft and good light transmittance. The thickness adjusting apparatus of claim 1, wherein the substrate pressing portion is made of a transparent material, a light transmittance having a good light resistance, and a substrate that can withstand the pressing force of the substrate. 5. The thickness adjusting apparatus of claim 4, wherein the substrate pressing part is made of quartz. Applying a sealant to the edge of the substrate coated with the ITO electrode; Dispersing the spacer on another substrate coated with the ITO electrode: and In the method of manufacturing a liquid crystal display device comprising the step of overlapping the two substrates prepared in the step so that the pixels are located in a predetermined position and curing the sealant, The sealant is an ultraviolet curable resin, Curing of the sealant is a method for manufacturing a liquid crystal display device, characterized in that by placing the two overlapping substrates in a thickness control device and irradiating ultraviolet rays under a constant pressure. The method of manufacturing a liquid crystal display device according to claim 6, wherein a balance induction device is attached to the substrate crimping portion of the thickness control device.