JPH02304420A - Production of liquid crystal display device - Google Patents

Abstract

PURPOSE:To form an oriented film having good film quality and uniform film thickness by applying a soln. prepd. by mixing the materials for the oriented film and a solvent on a glass substrate and removing the soln. mixture of the prescribed regions on the substrate by using a sponge-like member impregnated with the same solvent, then forming the oriented film. CONSTITUTION:The soln. 23 prepd. by mixing the materials for the oriented film and the solvent is applied by a spin coating method on the glass substrate 20 on which transparent electrodes 21 are formed. After the soln. mixture 23 of the prescribed regions on the glass substrate 20 is removed by using the sponge-like member 24 impregnated with the same solvent as the above- mentioned solvent, the soln. mixture 23 remaining on the glass substrate 20 is cured to form the oriented film. The soln. mixture 23 is easily dissolved by discharging the solvent contained in the sponge-like member 24 in such a manner and the simultaneously dissolved soln. mixture 23 is immediately absorbed by the sponge-like member 24; therefore, the soln. mixture 23 of the parts wiped with the sponge-like member 24 is cleanly removed. The oriented film having the good quality is obtd. in this way and the electrical characteristics of the liquid crystal display device are improved.

Description

[Detailed Description of the Invention] (Summary) Regarding a method for manufacturing a liquid crystal display device, more specifically, regarding a method for forming an alignment film for a liquid crystal display device, it is possible to form an alignment film with good film quality and uniform thickness. The purpose is to provide a method in which the alignment film material and solvent are mixed on a glass substrate on which a transparent electrode is formed. 8 liquid by spin coating, removing the mixed solution from a predetermined area on the glass substrate using a spongy member impregnated with the same solvent as the above solvent, and removing the mixed solution remaining on the glass substrate. and curing the mixed solution to form an oriented II2I2 acid.

[Industrial application field]

The present invention relates to a method for manufacturing a liquid crystal display device, and more specifically, to a method for forming an alignment film for a liquid crystal display device.

[Conventional technology]

Conventionally, alignment films have been created by a transfer printing method because it is easy to work with.

FIGS. 3(a) and 3(b) are perspective views illustrating a method for forming an alignment film using a conventional transfer printing method.

The same figure (a) shows the state before applying the mixed solution of the alignment film material and the solvent onto the glass substrate. A striped transparent electrode that is provided to apply an electric field to the liquid crystal. 3 is a transfer device for applying a mixed solution onto a glass substrate, and as shown in FIG. 6, a large number of concave/convex portions are provided on the surface.

First, a mixed solution is applied to the surface of this transfer device 3.

At this time, the mixed solution is retained without flowing down due to the unevenness of the surface. Next, the transfer device 3 is attached to the first glass substrate 1.
Rotate on top. The result is a transfer bag! Since the width of 3 is smaller than the width of the first glass base + 7fi 1,
As shown in FIG. 2B, the mixed solution is applied onto the first glass substrate l except for the electrode extension/sealing part 5.

Thereafter, when the mixed solution on the first glass substrate l is heated and cured, an alignment film 4 is formed.

Subsequently, the processes shown in FIGS. 3(C) to 3(e) are performed.

That is, as shown in FIG. 4(c), after attaching the drawer part 6 to each transparent electrode 2 of the electrode drawer part 5, the adhesive 7 is applied to the seal part 5. Note that in order to pour the liquid crystal onto the alignment film 4, a portion (0 part) where the adhesive 7 is not applied is provided.

Next, as shown in FIG. 4(d), a large number of spherical plastic balls 8 are placed on the alignment film 4 in order to maintain a space for filling the liquid crystal. Separately, in the same manner as in the case of the first glass substrate, a transparent electrode (not shown), an alignment film 10, and a lead-out portion 13 are formed on the second glass substrate 9. Thereafter, this second glass substrate 9 is stacked on top of the first glass substrate 1 and bonded and fixed.

Next, this is placed in a vacuum chamber (not shown) to reduce the pressure, and then 0 part is immersed in liquid crystal. After that, when the pressure inside the vacuum chamber is returned to atmospheric pressure, the alignment films 4 of the two glass substrates 1 and 9 are separated due to the pressure difference.
Liquid crystal is sucked up from part 0 into the space between and 10, and the space is filled.

In this way, the liquid crystal display device is completed (see figure (e)).
).

Note that FIG. 4 is a cross-sectional view of the liquid crystal display device of FIG. 3(e) taken along the line A-A shown by the dashed line.

[Problems to be Solved by the Invention] By the way, the unevenness of the transfer device 3 as shown in FIG. 6 can prevent the mixed solution from flowing down from the surface of the transfer device 3, but the unevenness prevents the transfer and coating The resulting film has a non-uniform thickness.

For this reason, as shown in Part 4, the alignment H of the liquid crystal display device
The liquid crystal 11 sandwiched between 4 and 10 also has a problem in that the film thickness becomes non-uniform and uneven alignment occurs in the liquid crystal display device.

As a countermeasure against this problem, there is a method of applying a mixed solution to a uniform thickness on a glass substrate using a spin coater.

FIGS. 5A to 5C are cross-sectional views illustrating a method of forming an alignment film using a spin coater.

First, as shown in FIG. 4A, a resist 11X16 is formed in advance on the electrode extension/seal section 15 on the glass substrate 14 by a normal method.

Thereafter, as shown in FIG. 3B, the mixed solution I7 is applied onto the glass substrate 14 by the spin coater 18, and then the mixed solution 17 is cured.

Next, the resist P14 is immersed in a resist stripping solution 19.
16, no alignment film is formed in the electrode extension/sealing part 15, and an alignment film 17a having a uniform thickness is formed only in the necessary portions (FIG. 3(C)).

By the way, when removing the resist film 16, the alignment film 17a
is exposed to the resist stripping solution 19, which is a solution of a polymeric substance, so that it changes in quality. For this reason, there is a problem in that a liquid crystal display device manufactured using this material has deteriorated electrical characteristics.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a method capable of forming an alignment film of good quality and uniform thickness.

[Means for Solving the Problem] The above problem consists of a step of applying a solution containing a mixture of an alignment film material and a solvent onto a glass substrate on which a transparent electrode is formed, and a step of applying the same solution as the solvent. A liquid crystal display comprising the steps of: removing a mixed solution from a predetermined area on a glass substrate using a spongy member impregnated with a solvent; and curing the mixed solution remaining on the glass substrate to form an alignment film. The problem is solved by a method for manufacturing a display device.

[Effect]

In the method for manufacturing a liquid crystal display device of the present invention, the mixed solution in a predetermined area, for example, the electrode extension part/sealing part, is removed using a spongy member impregnated with the same solvent as that of the mixed solution.

Therefore, the mixed solution is easily dissolved by discharging the solvent contained in the spongy member, and at the same time, the dissolved mixed solution is immediately absorbed by the spongy member, so that the area wiped with the spongy member cannot be mixed. Solution can be removed cleanly.

In addition, the alignment film formed by curing the mixed solution that remains after being removed in this way is of high quality because it is not exposed to a solution of a polymeric substance such as a resist stripping solution as in conventional methods. A highly oriented alignment film can be formed.

Furthermore, since the mixed solution is applied to a uniform thickness by spin coating and then cured to form the alignment film, the thickness of the alignment film can be made uniform.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1(a) to 1(g) are perspective views illustrating a method for manufacturing a liquid crystal display device using the method for forming an alignment film according to an embodiment of the present invention.

First, as shown in FIG. 2(a), a first glass substrate vi20 on which transparent electrodes 21 made of indium oxide are formed in stripes is placed on a spin coater 20 using a vacuum chuck method.
Fixed to. After that, a mixed solution 23 of polyimide as an alignment film material and N-methylpyrrolidone as a solvent
is dropped onto the first glass substrate 20.

Subsequently, the spin coater 22 is rotated to coat the mixed solution 2.
3 is spread on the surface of the first glass substrate 20. As a result, a thin film of the mixed solution 23 is spread over the entire surface to a substantially uniform thickness of 1
It is formed by 500 people ((b) in the same figure).

Next, after impregnating the sponge 24 with N-methylpyrrolidone, the sponge 24 is used to wipe a band-shaped area around the first glass substrate 20 with a width of about 5 mm. The N-methylpyrrolidone is discharged and this portion of the mixed solution 23 is easily dissolved and simultaneously absorbed into the sponge 24. As a result, the mixed solution 23 in the electrode extraction part/seal part 25 is easily and cleanly removed (FIG. 4(c)).

Next, as shown in the same figure (d), at a temperature of 250°C, 1
The mixed solution remaining on the first glass substrate 20 is cured by heat treatment for a period of time, and the alignment film 23a made of polyimide is formed.
form.

Next, each transparent electrode 21 exposed in the electrode extension part 25
After attaching the drawer leads 26 to the seal portion 2,
Apply adhesive 27 to 5. At this time, the adhesive 27 is not applied to a part (part D) ((s) of the same figure).

Next, as shown in FIG.
After dropping on t123a, only freon is grown. As a result, the plastic ball 28 is attached to the alignment film 23.
It is placed on top of a with uniform density. Also, a second glass substrate 29 on which a stripe-shaped transparent electrode (not shown) is formed.
An alignment film 30 and a drawer door 31 are formed thereon in the same manner.

Next, the second glass substrate ti29 is stacked on the first glass substrate 20 so that the directions of the stripes of the transparent electrodes are perpendicular to each other and the alignment films 30 and 23a face each other, and an adhesive is applied. Glue and fix with step 27. At this time, a space having a constant thickness of about 6 μm is created between the alignment films 23a and 30 for the plastic balls 28.

Next, after putting the pressure in a decompression chamber (not shown) and reducing the pressure, the D section is folded over the liquid crystal.Then, when the depressurization chamber is returned to atmospheric pressure, the liquid crystal is oriented from the D section to IP! due to the pressure difference. The liquid crystal 31 is absorbed into the space between 23a and 30, and the space is filled with liquid crystal 31 (
Figure (g)).

Note that FIG. 2 is a sectional view taken along the line E--E of the liquid crystal display device shown in FIG.

The liquid crystal 31 of the liquid crystal display device thus formed has a uniform thickness and an orientation It! Since it is sandwiched between 23a and 30, it has a constant film thickness. Therefore, when the liquid crystal display device is operated, alignment unevenness does not occur.

In addition, as shown in Figure (c), the mixed solution in the electrode extraction part/sealing part 25 is removed by wiping with a sponge soaked in the same solvent as that of the mixed solution, and then as shown in Figure (d). As shown, this is heated and cured to form an alignment film.

Therefore, unlike the conventional method, the alignment film is not exposed to chemicals such as a solution of a polymeric substance such as a resist stripping solution, so that a high-quality alignment film can be formed. Thereby, the electrical characteristics of the liquid crystal display device can be improved.

In the examples of the present invention, a polyimide/N-methylpyrrolidone solution was used as the mixed solution of the alignment film material and the solvent, but an aqueous methylcellulose solution may also be used.

In addition, in the embodiments of the present invention, an example was given in which the alignment film in a predetermined area is removed in a solution state in which the solvent is present, rather than in a dry state in which the solvent is completely removed. (especially when the alignment film is cross-linked and hardened)
This is because it becomes difficult to remove the alignment film in a predetermined region, so it is preferable to remove it in a solution state. However, even in a dry state with the solvent removed, it may be removed after the alignment film is formed as long as it is easily dissolved and removed by the solvent.

〔Effect of the invention〕

As described above, according to the method for manufacturing a liquid crystal display device of the present invention, before the mixed solution of the electrode extraction part/sealing part is cured, it is wiped off with a spongy member impregnated with a solvent. And can be removed cleanly.

Further, the alignment film formed by curing the mixed solution that remains after wiping is not exposed to chemicals such as resist stripping liquid, unlike conventional methods, so that a high-quality alignment film can be obtained. Thereby, the electrical characteristics of the liquid crystal display device can be improved.

Furthermore, since the mixed solution is formed by a spin coating method, the thickness of the alignment film can be made uniform. This can prevent alignment unevenness in the liquid crystal display device.

[Brief explanation of the drawing]

1(a) to (g) are perspective views explaining the present invention in detail; FIG. 2 is a sectional view of a liquid crystal display device manufactured by the manufacturing method of an embodiment of the present invention; FIG. ) to (e) are perspective views for explaining the conventional example, Fig. 4 is a cross-sectional view of a liquid crystal display device manufactured by the conventional manufacturing method, and Fig. 5 (a) to (c) are perspective views for explaining the conventional example. Cross-sectional view illustrating another method for forming an alignment film. FIG. 6 is a cross-sectional view of a transfer device used in a conventional method for forming an alignment film. (Explanation of symbols) 1.20 - first glass substrate, 2.12.21.32 - transparent electrode, 3 - transfer device, 4.10.17a, 23a, 30 - alignment film, 5.15.
25... Electrode extraction part/seal part, 6.13, 26.
31... Drawer lead, 7.27... Adhesive, 8.28... Plastic ball, 9.29... Second glass substrate, 11.33... Liquid crystal, 14... Glass Substrate, 16... Resist film, 17.23... Mixed solution, 18.22... Spin coater, 19... Resist stripping liquid, 24... Sponge.

Claims (1)

[Claims] A step of applying a solution of a mixture of an alignment film material and a solvent onto a glass substrate on which a transparent electrode is formed by a spin coating method; Using parts,
A method for manufacturing a liquid crystal display device, comprising: removing a mixed solution from a predetermined area on a glass substrate; and curing the mixed solution remaining on the glass substrate to form an alignment film.