JP2001255525A - Method of manufacturing liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a liquid crystal display device, capable of removing air bubbles without releasing the polarizing plate stuck once. SOLUTION: The polarizing plate is stuck to the liquid crystal display panel (step S1) and the sticking state of the polarizing plate is inspected (step S2). When there is generation of air bubbles taking place, micropores for liberate the air in the air bubbles is formed at the air bubbles part of the polarizing plate with laser beam irradiation (step S3), and the air in the air bubbles is liberated through the micropores by heating and pressurizing treatment (step S4), so as tightly to adhere the polarizing plate to the liquid crystal display panel surface. Then, when there is a transmissive liquid crystal display device with a backlight on the rear side, black ink is dripped on the micropore part (step S5) to prevent light leakage from the micropore by shielding the backlight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly, to eliminating bubbles generated between a liquid crystal display panel and a polarizing plate.

[0002]

2. Description of the Related Art In recent years, as a display device replacing a CRT,
Liquid crystal display devices are frequently used. This is because display quality, space convenience, low power consumption, and the like, which are the characteristics of the liquid crystal display device, are not inferior to CRTs.

[0003] However, there are still many problems in manufacturing a liquid crystal display device, and a 100% yield cannot be ensured because, for example, many thin films are formed.
Furthermore, recently, the demand for larger and higher definition liquid crystal display devices has made it extremely difficult to form a thin film finely.

Therefore, in the manufacturing process of the liquid crystal display device, defects in processes not related to thin film formation, such as a polarizing plate attaching process and a mounting process for mounting a driving driver, etc., are reduced, and the liquid crystal display device is reduced to a small extent. It is important to improve the yield.

[0005] One such defect in a process not related to the formation of a thin film is that, when air is sandwiched between the polarizing plate and the liquid crystal display panel when the polarizing plate is attached, bubbles are generated, resulting in display defects. is there. This is caused by a foreign substance (dust, resin, glass dust, etc.) being bitten or a problem caused by a polarizing plate attaching device.

[0008] When a defect due to air bubbles occurs, it is usually shown in FIG.
The rework work shown in Fig. 1 is required. This rework operation will be described below.

First, a polarizing plate is attached to a liquid crystal display panel according to a general operation (step S11), and the state of attachment of the polarizing plate is inspected (step S12). If air bubbles are generated, the polarizing plate is peeled off (Step S
13) Then, the surface of the liquid crystal display panel is cleaned (step S1).
4) After that, the polarizing plate is again adhered to the liquid crystal display panel (step S15), and a heating / pressing process is performed to enhance the adhesion between the polarizing plate and the liquid crystal display panel (step S16).
I do.

However, since the polarizing plate has high adhesiveness, it is not easy to peel off the polarizing plate once attached. Therefore, when the polarizing plate is peeled off, the liquid crystal display panel itself may be damaged.

As a method for preventing the defective attachment of the polarizing plate due to air bubbles, usually, before the polarizing plate is attached, a scribing cleaning of the liquid crystal display panel surface using a cutting tool or a polishing sheet or the like is performed immediately after the cleaning with a brush. Is used.

However, such a method cannot sufficiently remove foreign matter and cannot completely prevent the generation of bubbles. Therefore, as another method, a liquid crystal display is required before foreign matter adheres to the surface of a liquid crystal display panel. Coating the surface of the panel,
JP-A-11-337930 discloses a method of removing a coating immediately before attaching a polarizing plate to prevent bubbles from being generated by foreign matter.
No. pp. 139 to 163.

[0011]

However, even if the method proposed in Japanese Patent Application Laid-Open No. H11-337930 is used, the problem of the polarizing plate sticking device, the unevenness of the liquid crystal display panel itself, and the polarizing plate member itself cannot be solved. It is not possible to prevent the generation of air bubbles unrelated to foreign matter due to undulations or the like. If air bubbles are generated, a rework operation is required to be treated as a defective product as described above.

In the reworking operation, as described above, since the polarizing plate has high adhesiveness, it is not easy to peel off the polarizing plate once adhered. Therefore, it is necessary to remove the polarizing plate and clean the surface of the liquid crystal display panel. In addition, there is a concern about damage to the liquid crystal display panel. Furthermore, since the size of the polarizing plate has been increased with the recent increase in the size of the liquid crystal display device, and the polarizing plate has become expensive, the rework operation of changing the polarizing plate causes an increase in cost.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a method of manufacturing a liquid crystal display device capable of removing bubbles without peeling off a polarizing plate once adhered. The purpose is.

[0014]

In order to achieve the above-mentioned object, a method of manufacturing a liquid crystal display device according to the present invention comprises the steps of: attaching a polarizing plate to a liquid crystal display panel; In the case where bubbles are generated during the process, fine holes are formed in the polarizing plate for irradiating a laser beam to release air in the bubbles.

Further, the method is characterized in that, after the air in the air bubbles is released, black ink is dropped into the fine holes.

According to the present invention, the liquid crystal display panel in which bubbles are generated is irradiated with laser light, and fine holes for allowing air in the bubbles to escape are formed in the bubble portion of the polarizing plate. Thereafter, the liquid crystal display panel is set in a heating / pressing device.
Since the heating and pressurizing device can raise the temperature inside the device to a specific temperature and apply pressure to the liquid crystal display panel, pressure is also applied to the part of the polarizing plate where bubbles are generated, and the air in the bubbles is fine. The polarizing plate escapes from the hole and adheres to the liquid crystal display panel surface.

Further, in the case of a transmission type liquid crystal display device having a backlight on the back side, light leakage occurs because a polarization hole is not formed in the polarization plate by forming a micro hole in the polarizing plate. In order to prevent this light leakage, black ink is dropped on the fine holes to block the backlight light.

As described above, in the work of reworking the polarizing plate in which bubbles are generated, damage to the liquid crystal display panel due to peeling of the polarizing plate is prevented, and the cost of members by re-attaching another polarizing plate is reduced. Further, the rework time can be reduced.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a process chart showing a work flow according to the present invention.

According to the present invention, as shown in FIG. 1, a polarizing plate is attached to a liquid crystal display panel as in the prior art (step S).
1) Inspect the state of pasting of the polarizing plate (Step S2). If bubbles are generated, micro holes for irradiating the laser beam to release the air in the bubbles are formed in the bubbles of the polarizing plate (step S3), and the heating / pressing process (step S4) is performed. ) To allow the air in the air bubbles to escape from the fine holes, and bring the polarizing plate into close contact with the liquid crystal display panel surface. And in the case of a transmissive liquid crystal display device having a backlight on the back,
Black ink is dropped on the minute holes (step S5) to block the backlight light and prevent light leakage from the minute holes.

Here, a laser processing apparatus for forming a fine hole will be described. FIG. 2 is a perspective view showing a laser processing apparatus.

As shown in FIG. 2, the laser processing apparatus comprises a suction stage 2 on which a liquid crystal display panel 1 is set, and a laser irradiation head 3 having XY moving axes.
The laser irradiation head 3 is mounted so that the laser irradiation direction is perpendicular to the suction stage 2.
A camera 4 is attached to the laser irradiation head 3 so that a laser irradiation target can be confirmed on a monitor 5. A pointer is displayed on the monitor 5 so that the laser irradiation position can be confirmed.

Next, the rework operation will be described. FIG. 3 shows that, after the polarizing plate 6 is attached, bubbles
FIG. 4 is a cross-sectional view showing the liquid crystal display panel 1 in which the phenomenon occurs, and FIG.
FIG. 5 is a cross-sectional view showing a state in which fine holes 8 are formed in the polarizing plate 6, FIG. 5 is a cross-sectional view showing a heating / pressing device 9, and FIG. 6 is an explanatory view showing how bubbles 7 disappear.

The liquid crystal display panel 1 having bubbles 7 as shown in FIG. 3 is set on a suction stage 2 of a laser processing apparatus as shown in FIG. At this time, the liquid crystal display panel 1 is set so that the surface where the bubbles 7 are generated is on the side of the laser irradiation head 3. Then, the laser irradiation head 3 is moved to the bubble 7
After moving to the generation position and confirming the bubble 7 on the monitor 5, the portion of the bubble 7 is irradiated with laser light.

As the type of the laser beam, the polarizing plate 6 can be processed without transmitting through the inside of the liquid crystal display panel 1 and affecting the wiring pattern of the liquid crystal display panel 1.
It is preferable to use an ultraviolet pulse laser. The irradiation conditions of the laser beam need to be optimized depending on the type of the polarizing plate 6. For example, the output is 600 W and the irradiation size is 50 μm.
What is necessary is just to carry out under irradiation conditions of x50 micrometers.

By irradiating such a laser beam, fine holes 8 can be formed in the polarizing plate 6 in the bubble 7 portion as shown in FIG. The diameter of the fine holes 8 needs to be processed as small as possible in consideration of light leakage after rework.

After forming the fine holes 8, the liquid crystal display panel 1
Is placed in a heating / pressing device 9 as shown in FIG. 5, and the inside of the device is heated to a constant temperature and pressurized to a constant pressure. Heating and pressurization are performed at a temperature inside the device of 60 degrees and a pressure inside the device of 7 kg / cm.
² and left in the apparatus for about 20 minutes.

In this way, as shown in FIG. 6, pressure is applied to the bubble 7 portion of the polarizing plate 6, so that the air in the bubble 7 escapes from the fine hole 8 formed by the laser beam, and the polarizing plate 6 Adheres to the surface of the liquid crystal display panel 1, and the rework operation is completed.

Here, when the liquid crystal display device is a transmissive liquid crystal display device having a backlight, the backlight light leaks from the fine holes 8 formed by the rework operation without being polarized. Therefore, it is necessary to prevent the backlight light from leaking from the fine holes 8.

FIG. 7 is a perspective view showing a light leakage countermeasure device. The light leakage countermeasure device is composed of a suction stage 11 for setting the liquid crystal display panel 10 after laser processing and heating / pressing processing, and a black ink dropping head 12 for dropping black ink into the fine holes 8. I have. The black ink dropping head 12 has a moving axis that can move in the X and Y directions,
A camera 13 for checking the object is provided,
Monitor 1 for displaying images captured from camera 13
4 are prepared. A pointer is displayed on the monitor 14 so that the position where the black ink is dropped can be checked.

Next, the procedure of dropping black ink will be described. The liquid crystal display panel 10 after the laser processing and the heating / pressing processing is set on the suction stage 11. At this time, the liquid crystal display panel 10 is set so that the surface on which the laser processing has been performed is on the black ink dropping head 12 side. Then, the black ink dropping head 12 is moved to the position of the fine hole 8, and after checking the fine hole 8 and the black ink dropping position on the monitor 14, the black ink is dropped into the fine hole 8.

With this configuration, even when the liquid crystal display device is a transmission type liquid crystal display device having a backlight,
It is possible to prevent the backlight light from leaking from the minute holes 8.

[0033]

As described above, according to the present invention,
Prevents damage to the liquid crystal display panel due to peeling of the polarizing plate in the rework work of the polarizing plate in which bubbles are generated, reduces the cost of members by attaching another polarizing plate again, and further shortens the rework time. be able to.

[Brief description of the drawings]

FIG. 1 is a process chart showing a work flow according to the present invention.

FIG. 2 is a perspective view showing a laser processing apparatus.

FIG. 3 is a cross-sectional view showing a liquid crystal display panel in which air bubbles not caused by foreign matter have been generated after a polarizing plate has been attached.

FIG. 4 is a cross-sectional view illustrating a state in which micro holes are formed in the polarizing plate of FIG. 3;

FIG. 5 is a sectional view showing a heating / pressing device.

FIG. 6 is an explanatory diagram showing how bubbles disappear.

FIG. 7 is a perspective view showing a light leakage countermeasure device.

FIG. 8 is a process diagram showing a conventional work flow.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 liquid crystal display panel 2 suction stage 3 laser irradiation head 4 camera 5 monitor 6 polarizing plate 7 bubble 8 microhole 9 heating / pressing device 10 liquid crystal display panel 11 suction stage 12 black ink dropping head 13 camera 14 monitor

Claims (2)

[Claims] When a bubble is generated between the liquid crystal display panel and the polarizing plate after the polarizing plate is attached to the liquid crystal display panel, a laser beam is irradiated to release air in the bubble. A method for manufacturing a liquid crystal display device, comprising forming fine holes in the polarizing plate. 2. The method for manufacturing a liquid crystal display device according to claim 1, wherein black ink is dropped into the fine holes after the air in the air bubbles is released.