WO1997044705A1

WO1997044705A1 - Liquid crystal display panel and method of manufacturing the same

Info

Publication number: WO1997044705A1
Application number: PCT/JP1997/001684
Authority: WO
Inventors: Satoru Katagami
Original assignee: Seiko Epson Corporation
Priority date: 1996-05-22
Filing date: 1997-05-19
Publication date: 1997-11-27
Also published as: CN1194696A; TWI229221B; JP3700180B2; CN1140840C; KR19990028802A; KR100485964B1

Abstract

A transparent electrode (11) the number of which corresponds to that of a picture element is formed on a liquid crystal display region on an inner surface of a liquid crystal panel substrate (10), and external connecting terminals (12) at free end portions of a plurality of leader lines (18) conductively connected to this transparent electrode on the outer side of the liquid crystal display region. On the inner surface of the liquid crystal panel substrate on which the transparent electrode, leader lines and external connecting terminals are formed, an acrylic thermosetting resin is applied to the whole area thereof to a small thickness by a spin-coating method to form a transparent insulating film (16). A polyimide resin is then applied to the portion of the liquid crystal display region which is on an outer surface of this transparent insulating film, and the resultant layer of polyimide resin is fired to form an orientation film (14). When this orientation film is rubbed by a rubbing roller, rubbing unevenness rarely occurs since the leader lines and external connecting terminals are covered with the transparent insulating film, so that the display unevenness on a liquid display panel decreases.

Description

TECHNICAL FIELD The present invention relates to a liquid crystal display panel and a method for manufacturing the same, and more particularly, to a manufacturing technique for performing a rubbing process on an inner surface of a liquid crystal panel substrate. Conventionally, when forming a liquid crystal display panel, a transparent electrode made of IT0 (indium tin oxide) is formed for each pixel area in the liquid crystal display area on the inner surface of one glass liquid crystal panel substrate. Then, the extraction wiring connected to the transparent electrode ′ is drawn out of the liquid crystal display area, and the external connection terminal connected to the end of the extraction wiring is arranged to form an external connection terminal part. On the other hand, in the liquid crystal display region, an alignment film is formed by printing with a resin such as polyimide or polyvinyl alcohol. This alignment film is subjected to a rubbing treatment described later.

A transparent electrode is also formed on the inner surface of the other liquid crystal panel substrate, and a color filter is formed on the transparent electrode. The surface of the color filter is covered with a protective film made of a transparent resin, and a rubbing treatment is performed after an orientation film similar to the above is formed.

The two liquid crystal panel substrates thus formed are bonded together via a sealing material formed so as to surround the liquid crystal display area, and then the liquid crystal is filled in the liquid crystal enclosing area surrounded by the sealing material. You. 5 and 6 show the cross-sectional structure of the above liquid crystal panel substrate, and FIG. 7 shows the plan structure thereof. 6 and 7 show a liquid crystal panel substrate 10 having a transparent electrode 11, a lead wiring 18, an external connection terminal 12, and a direction film 14 formed on the surface. When rubbing is performed after forming the transparent electrode 11, the lead wiring 18, the external connection terminal 12, and the alignment film 14 on the surface of the liquid crystal panel substrate 10, if the rubbing treatment is performed, the hairs may become dense on the peripheral surface. While rotating the rubbing roller 15 around which the ragged cloth (rubbing sheet) is wound, the surface of the liquid crystal panel substrate 10 is rubbed diagonally as shown in FIG. Many fine grooves are formed on the surface of the alignment film 14 by the hairs 15a formed on the surface of the rubbing roller. When the liquid crystal is brought into contact with the surface of the alignment film 14, the liquid crystal molecules in contact with the groove are oriented in the direction in which the groove is formed.

However, in the above-described conventional rubbing treatment, as shown in FIG. 7, a part of the rubbing roller 15 comes into contact with the external connection terminal 13 and the surface of the lead-out wiring 18. The bristle 15a of the rubbing roller 15 hits the external connection terminal 12 and the lead-out wiring 18 formed on the terminal 13 and adheres to the rubbing roller tip as shown in Fig. 6. Debris 15 b, such as shavings of the bristles 15 a and shavings of the alignment film 14, are removed by the external connection terminals 12 and the side walls of the lead wires 18. On the other hand, the attached portion 15b is not removed from the surface of the rubbing roller 15 that does not contact the external connection terminal portion 13 or the lead-out wiring 18. Therefore, out of the surface of the alignment film 14 in contact with the surface of the rubbing roller 15, in the region A shown in FIG. In the region B, a large amount of the deposit 15b adheres to the surface of the alignment film 14 and the rubbing state becomes uneven as shown in the figure, which causes a problem that display unevenness occurs in the liquid crystal display area. is there. Accordingly, the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a liquid crystal display panel and a method of manufacturing the liquid crystal display panel, in which unevenness due to a rubbing roller is prevented during rubbing processing, and display unevenness of a liquid crystal display is reduced. It is to provide Means taken by the present invention to solve the above problems are

Two liquid crystal panel substrates each having an applied electrode pattern in a liquid crystal display area on the inner surface thereof; a liquid crystal layer disposed between the liquid crystal panel substrates; and at least one of the liquid crystal panel substrates. On the inner surface of the liquid crystal panel substrate, the number of the lead wires connected to the applied electrode pattern and / or the external connection terminal portions connected to the lead wires, and the number of the lead wires and / or the external connection terminal portions is small. A liquid crystal display panel comprising: an insulating film that covers a peripheral portion of the liquid crystal display region that partially covers the liquid crystal display region and that can reduce surface friction; and an alignment film that covers the liquid crystal display region.

According to this means, at least a part of the lead wiring and / or the external connection terminal around the liquid crystal display area is covered with the insulating layer, so that the surface friction of the covered part is reduced. Therefore, unevenness in the rubbing treatment for the alignment film caused by contact with the lead wiring and the external connection terminal portion is reduced, and a liquid crystal display panel with reduced display unevenness can be obtained.

The surface friction of the insulating layer should be lower than that of the lead-out wiring and the external gun contact part as a whole, and as a result, the alignment film provided by the material used for the rubbing treatment (rubbing roller, etc.). Reduced surface impact …

7/44705

o る o

Further, the insulating layer and the alignment film may be formed so as not to overlap each other, may be formed so as to completely overlap as described later, or may be formed so as to partially overlap. Is also good.

In particular, when the insulating film is made of an acrylic resin, it is easy to form a transparent film by using an acrylic resin, and an insulating film with low surface friction can be formed. Can be obtained reliably.

In this case, since the thickness of the insulating film is 100 to 20 OA, the thickness is small even if the insulating film is formed of an acrylic resin having low surface friction. Therefore, the adhesion of the insulating film is not easily reduced, so that the liquid crystal display panel can be prevented from peeling off.

When a color filter is formed on the inner surface of one of the liquid crystal panel substrates, and the insulating film covers the surface of the color filter as a protective film, a color filter is formed. Since the unevenness of the rubbing process can be prevented by the insulating film also serving as the protective film, the increase in the number of manufacturing steps can be suppressed.

Further, when a color filter is formed on the inner surface of the other liquid crystal panel substrate, and the insulating film covers the surface of the color filter as a protective film, a color filter is formed. Since the rubbing process can be prevented from being uneven by the insulating film also serving as the filter protective film, an increase in the number of manufacturing steps can be suppressed. In addition, the quality of the rubbing process can be expected to be improved by reducing the surface friction of the insulating film around the orientation film formed on the inner surface of the other liquid crystal panel substrate. Since a protective film of the same color can be formed with the same material as the insulating film of the substrate, material management becomes easy, and an increase in manufacturing cost can be suppressed.

Next, as a method of manufacturing a liquid crystal display panel, a liquid crystal layer is interposed. Forming at least one of the two liquid crystal panel substrates on the inner surface of one of the liquid crystal panel substrates, a lead wiring connected to an application electrode pattern formed in the liquid crystal display area and / or an external connection terminal portion. An insulating film that covers a peripheral portion of the liquid crystal display region including at least a part of the lead wiring and / or the external connection terminal portion, and that can reduce surface friction; and Forming an alignment film to be coated; and thereafter, performing a rubbing process on the inner surface of the liquid crystal panel substrate.

In this case, when the insulating film and the alignment film are formed so as not to overlap each other, either the insulating film or the alignment film may be formed first.

Here, after the step of performing the rubbing treatment, there may be a step for removing the insulating film covering the external connection terminal portion.

Further, after forming the insulating film on almost the entire inner surface of the liquid crystal panel substrate, the alignment film can be formed on the surface of the insulating film in the liquid crystal display region. In this case, since the insulating film is formed on almost the entire surface of the liquid crystal panel substrate, there is no need for selective formation or patterning treatment. it can. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an enlarged end view showing a structure of a liquid crystal display according to an embodiment of the present invention.

FIG. 2 is a schematic plan view showing how rubbing is performed in the same embodiment. FIG. 3 is an enlarged end view showing a state in which a rubbing process is performed in the embodiment (an end view showing a state cut along the line m-HI in FIG. 2).

FIG. 4 is an enlarged end view showing the structure of a liquid crystal display according to another embodiment of the present invention.

FIG. 5 is an enlarged end view showing a structural example of a conventional liquid crystal display panel.

FIG. 6 is an enlarged end view showing a state in which a rubbing process is performed in a conventional method of manufacturing a liquid crystal display panel (an end view showing a state cut along line VV in FIG. 7).

FIG. 7 is a schematic plan view showing how a rubbing process is performed in a conventional liquid crystal display panel manufacturing method. Preferred Embodiment for Carrying Out the Invention Next, an embodiment of a method for manufacturing a liquid crystal display panel according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is an enlarged end view showing a partial structure of a color liquid crystal display panel formed according to the present embodiment, FIG. 2 is a plan view showing a rubbing process of the panel, and FIG. FIG. 3 is an enlarged end view showing a state of a rubbing process step of the panel.

In the present embodiment, a transparent electrode 11 is formed for each pixel region in a portion to be a liquid crystal display region on the inner surface of the liquid crystal panel substrate 10. Further, by applying aluminum or another metal material, a plurality of lead wires 18 conductively connected to the transparent electrode 11 are formed so as to extend from the inside of the liquid crystal display area to the outside. In addition, an external connection terminal 12 is formed outside the liquid crystal display area at the tip of the lead-out wiring 18 by a conductive gun. Is done. The thickness of the external connection terminal 12 is usually about 100 to 200 OA.

On the inner surface of the liquid crystal panel substrate 10 on which the transparent electrodes 11, the lead wires 18 and the external connection terminals 12 are formed, an acrylic thermosetting resin is entirely coated by a spin coating method. The transparent insulating film 16 is formed in such a manner that the film is hardened under a heating condition suitable for the resin material, and finally the film thickness becomes about 100 to 20 OA. Next, a polyimide resin is applied in the liquid crystal display area on the surface of the transparent insulating film 16 and baked to form an alignment film 14 having a thickness of 700 to 80 OA.

On the other hand, a transparent electrode 21 is formed in the liquid crystal display area on the inner surface of the liquid crystal panel substrate 20, and a color filter 22 is formed on the surface by printing. On the entire surface including the surface of the color filter 22 and the outside of the liquid crystal display area, a thickness of about 200 A is formed by the spin-coating method using the same material as the transparent insulating film 16 described above. A transparent insulating film 23 is formed. In the liquid crystal display area on the surface of the transparent edge film 23, an alignment film 24 having the same material and substantially the same thickness as the above-described alignment film 14 is formed.

The liquid crystal panel substrates 10 and 20 having the layer structure formed on the inner surface as described above are shown in FIGS. 2 and 3 (the drawing shows the processing state of the liquid crystal panel substrate 10). The rubbing treatment shown in) is performed. There are various rubbing methods. In this embodiment, a rubbing roller 15 is used in which a rubbing sheet having a large number of bristles 15a on its surface is wound around a cylindrical roller. When the rubbing roller 15 is pressed against the liquid crystal panel substrate 10 with a predetermined pressure, the contact surface with the liquid crystal panel substrate rotates in the same direction as the moving direction of the rubbing roller 15. The inner surface of the liquid crystal panel substrate 10 is rubbed while rotating in a rotating direction such that the rubbing roller is moved. Although the transparent insulating film 16 is formed extremely thickly with respect to the thickness of the external connection terminal 12 and the lead-out wiring 18, the unevenness existing on the surface of the external connection terminal 12 and the lead-out wiring 18 is reduced. Since the projecting shapes are covered so as to match each other, and the transparent insulating film 16 is formed of an acrylic resin, the surface friction is lower than that of the lead wiring 18 and the external connection terminal 12. Therefore, when rubbing is performed by the rubbing roller 15, shavings of the hair 15 a may be generated between the hair 15 a and the external connection terminal 12 or the lead-out wiring 18, and Debris and bristle of the alignment film material generated by contact with the alignment film of the surface 1 5a The debris of the a itself contacts only the external connection terminal 12 and the lead-out wiring 18 External connection terminal 12 and the lead-out wiring 1 A situation in which the alignment film 14 is removed by the side wall 8 does not occur, and as a result, a uniform rubbing treatment can be performed on the alignment film 14 in the liquid crystal display region.

The rubbing process is similarly performed on the liquid crystal panel substrate 20 in a direction orthogonal to the direction of the rubbing process performed on the liquid crystal panel substrate 10. Also in this liquid crystal panel substrate 20, a plurality of lead-out wires conductively connected to each of the plurality of transparent electrodes 21 are provided, and these lead-out wires are connected to the external connection terminals formed on the liquid crystal panel substrate 10. It is conductively connected to the child 12.

Next, as shown in FIG. 1, the liquid crystal panel substrate 10 and the liquid crystal panel substrate 20 are interposed via a sealing material 30 made of an ultraviolet curing resin or the like with the inner surfaces on which the alignment films are formed facing each other. And stick them together. The sealing material 30 is formed in a frame shape so as to surround the liquid crystal display area, and a liquid crystal sealing area is formed by bonding the liquid crystal panel substrates 10 and 20 together. A part of the sealing material 30 is chipped in advance so that a sealing port is formed in the liquid crystal sealing area.

Finally, inject the liquid crystal 31 from the filling port and seal the filling port. Thus, a liquid crystal display panel sandwiching the liquid crystal layer is formed. Thereafter, a part of the liquid crystal panel substrate is cut off to expose the external connection terminals, and the transparent insulating film 16 covering the surface is removed by plasma assing or the like. When a plurality of liquid crystal display units are formed integrally, each liquid crystal display unit is cut and separated.

In the above example, the external connection terminal portion 13 is formed only on the liquid crystal panel substrate 10. However, even in the liquid crystal panel substrate 20 having no external connection terminal portion, the external connection terminal portion 13 is formed on the outside of the liquid crystal display area. Since the lead wiring exists, rubbing unevenness due to the lead wiring can be prevented.

Here, the liquid crystal panel substrate 10 may not be provided with external connection terminal portions, and the liquid crystal panel substrate 20 may be provided with external connection terminal portions. Further, external connection terminals may be provided on both substrates 10 and 20. In this case, since the transparent insulating films 16 and 23 are formed on any of the liquid crystal panel substrates 10 and 20, even if the external connection terminal portion is formed on any of the substrates, As in the case of (1), it is possible to prevent unevenness in the rubbing treatment of the alignment film.

The transparent insulating films 16 and 23 are not limited to the above materials and may be other materials as long as the surface friction can be reduced more than the external terminal portion 13. In addition, when manufacturing a liquid crystal panel constituting a reflective liquid crystal display, a non-transparent insulating film may be formed on a substrate on the reflective side (particularly, a reflective electrode is formed instead of a transparent electrode). Good.

The thickness of the transparent insulating film is preferably 200 A or less in order to secure the adhesion between the liquid crystal panel substrate and the sealing material, and can be easily formed by a spin coating method. It is desirable that the thickness be 10 OA or more. If the thickness of the transparent insulating film is greater than 200 A, the adhesion is reduced, and there is a possibility that separation between the substrates occurs in the liquid crystal panel. Increases.

In general, a film with low surface friction has low adhesion, so even if a film made of a different material is used instead of the above-mentioned transparent insulating film, reducing the thickness and increasing the adhesion will not remove the LCD panel substrate. Significant in preventing it. In the present invention, since a film having a particularly low surface friction is formed, even if the film is considerably thinner than the thickness of the external connection terminal, it is effective in preventing unevenness of the rubbing treatment. By applying the thin film at the terminal portion, the adhesion of the formed film itself to the liquid crystal panel substrate can be improved. It is desirable that the film thickness to be formed is 5 to 50% or less of the thickness of the external terminal portion.

In the conventional manufacturing process of a liquid crystal display panel, display unevenness due to unevenness of the rubbing treatment occurred at a rate of more than 90%, though varying in degree, but according to the present embodiment described above. In a liquid crystal panel substrate manufactured by forming an insulating film with a thickness in a range of about 150 to 190 A, the observable display unevenness due to the rubbing treatment was drastically reduced to 10% or less. As a result, the yield in the manufacturing process has been greatly increased, and the display quality of the final product has been greatly improved.

In the above embodiment, the transparent insulating film is formed by coating on the entire inner surface of the liquid crystal panel substrate. However, in order to obtain the same effect, at least the area around the liquid crystal display area including the lead wiring and the external terminal portion is required. An insulating film may be formed in the area. Even in this case, since the periphery of the alignment film is uniformly covered with the insulating film, unevenness in the rubbing treatment can be similarly prevented.

FIG. 4 shows an end face structure of a liquid crystal display panel of an embodiment different from the above. In this embodiment, the same parts as those in the previous embodiment are denoted by the same reference numerals, and description thereof will be omitted. In this embodiment, the transparent electrode 1 _Λ ―,

97/44705

11

An external connection terminal 12 is provided at the end of the extraction wiring 18 connected to 1 in the same manner as the previous embodiment, but the insulating film 1 is formed only on the liquid crystal display area and the extraction wiring 18. 6 is formed, and an insulating film is not formed on the external connection terminals 12.

In this embodiment, the rubbing unevenness caused by the external connection terminal 12 cannot be prevented by disposing the peripheral portion 16a of the insulating film on the lead-out wiring 18, although it cannot be prevented. In addition, it is possible to prevent rubbing unevenness caused by the lead wiring 18 formed in a portion closer to the liquid crystal display area than the external connection terminal 12, and to provide the insulation on the external connection terminal 12 later. There is an advantage that it is not necessary to remove the film.

As described above, the effect of the present invention is exerted by covering the periphery of the liquid crystal display area including at least one of the lead-out wiring and the external connection terminal by the insulating film described above. Is done. For example, an insulating film similar to the transparent insulating films 16 and 23 may be formed only on the lead wiring 18 as shown in FIG. Alternatively, for example, out of the periphery of the liquid crystal display area, the side on the side where the rubbing process is first performed by the rubbing roller 15 shown in FIG. 2 (the upper side of the liquid crystal display area in FIG. 2). Only the connection terminal 12 or the lead wiring 18 may be covered with an insulating film. The lead wires 18 and the external connection terminals 12 formed below the liquid crystal display area shown in FIG. 2 do not affect the rubbing process on the liquid crystal display area by the rubbing roller 15. It is. INDUSTRIAL APPLICABILITY As described above, according to the present invention, the pulling around the liquid crystal display area Since the insulating layer covers part of the outgoing wiring and / or the external connection terminal, surface friction is reduced, so that it comes into contact with the outgoing wiring and / or the external connection terminal. The unevenness of the rubbing process that has occurred can be reduced, and the display unevenness of the liquid crystal display panel can be reduced. Therefore, the display quality of the liquid crystal display panel can be improved, and the yield at the time of manufacturing the liquid crystal display panel can be increased.

Claims

Λ ml i ni! PCT / JP97 / 01684O 97/44705 13 Claims

1. Two liquid crystal panel substrates with applied electrode patterns in the liquid crystal display area on each inner surface,

A liquid crystal layer disposed between the liquid crystal panel substrates,

An extraction wiring connected to the application electrode pattern and / or an external connection terminal connected to the extraction wiring on at least one inner surface of the liquid crystal panel substrate of the liquid crystal panel substrate;

An insulating film that covers a peripheral portion of the liquid crystal display region including at least a part of the lead-out wiring and / or the external connection terminal portion, and that can reduce surface friction;

A liquid crystal display panel comprising: an alignment film covering the liquid crystal display region.

2. The liquid crystal display panel according to claim 1, wherein the insulating film is made of an acrylic resin.

3. The liquid crystal display panel according to claim 2, wherein the thickness of the insulating film is 100 to 200 A.

4. The liquid crystal display panel according to claim 1, wherein a color filter is formed on an inner surface of one of the liquid crystal panel substrates, and the insulating film covers a surface of the power filter as a protective film.

5. The liquid crystal display panel according to claim 1, wherein a color filter is formed on an inner surface of the other liquid crystal panel substrate, and the insulating film covers a surface of the color filter as a protective film.

6. At least one of the two liquid crystal panel substrates for the interposition of the liquid crystal layer, on at least one of the inner surfaces of the liquid crystal panel substrate, the lead-out wiring connected to the applied electrode pattern formed in the liquid crystal display area and / or Or forming an external connection terminal portion, and thereafter covering the periphery of the liquid crystal display region including at least a part of the lead wiring and / or the external connection terminal portion, and reducing surface friction. A method for manufacturing a liquid crystal display panel, comprising: a step of forming an insulating film and an alignment film covering the liquid crystal display region; and a step of rubbing the inner surface of the liquid crystal panel substrate thereafter.

7. The method for manufacturing a liquid crystal display panel according to claim 6, comprising a step of removing the insulating film covering the external connection terminal portion after the step of performing the rubbing treatment.

8. The method for manufacturing a liquid crystal display panel according to claim 6, wherein the insulating film is formed on substantially the entire inner surface of the liquid crystal panel substrate, and the alignment film is formed on the surface of the insulating film in the liquid crystal display region.

9. The method for manufacturing a liquid crystal display panel according to claim 6, wherein the insulating film is made of an acrylic resin.

10. The method for manufacturing a liquid crystal display panel according to claim 9, wherein the thickness of the insulating film is 100 to 200A.

11. The liquid crystal panel according to claim 6, wherein a force is applied on an inner surface of one of the liquid crystal panel substrates. 7/44705

15 A method for manufacturing a liquid crystal display panel, wherein a color filter is formed, and the insulating film is formed as a protective film on the surface of the color filter.

12. The liquid crystal according to claim 6, wherein a force filter is formed on the inner surface of the other liquid crystal panel substrate, and the insulating film is formed as a protective film on the surface of the color filter. Display panel manufacturing method.