KR19990028802A - Liquid crystal display panel and its manufacturing method - Google Patents

Abstract

A transparent electrode 11 is formed for each pixel region in the liquid crystal display region on the inner surface of the liquid crystal panel substrate 10, and the external connection terminal 12 provided at the front end of the plurality of lead wires 18 conductively connected to the transparent electrode is provided. It is formed outside the liquid crystal display area. On the inner surface of the liquid crystal panel substrate on which the transparent electrode, the lead wires, and the external connection terminals are formed, a thin acrylic curable resin is formed on the entire surface by spin coating to form a transparent insulating film 16. Next, a polyimide resin is applied and baked in the liquid crystal display region on the surface of this transparent insulating film to form an alignment film 14. When the rubbing process is performed on the alignment film by the rubbing roller, rubbing is unlikely to occur because the lead wires and the external connection terminals are covered by the transparent insulating film, and display unevenness of the liquid crystal display panel is reduced.

Description

Liquid crystal display panel and its manufacturing method

Conventionally, when forming a liquid crystal display panel, a transparent electrode made of ITO (indium tin oxide) is formed for each pixel region in the liquid crystal display region on the inner surface of one glass liquid crystal panel substrate, and the lead-out connected to the transparent electrode is formed. The wiring is drawn out to the outside of the liquid crystal display region, and external connection terminals connected to the leading end of the lead-out wiring are arranged to form an external connection terminal portion. On the other hand, in a liquid crystal display area | region, an alignment film is printed-formed by resin, such as polyimide and polyvinyl alcohol. The rubbing process mentioned later is performed to this alignment film.

A transparent electrode is formed also on the inner surface of the other liquid crystal panel board | substrate, and a color filter is formed on this transparent electrode. The surface of the color filter is covered with a protective film made of a transparent resin, and further, a rubbing treatment is performed after the above-described alignment film is formed.

The two liquid crystal panel substrates thus formed are adhered through a sealing material formed to surround the liquid crystal display region, and then the liquid crystal is filled in the liquid crystal sealing region surrounded by the sealing material.

The cross-sectional structure of the liquid crystal panel substrate is shown in Figs. 5 and 6, and the planar structure is shown in Fig. 7, respectively. 6 and 7 show a liquid crystal panel substrate 10 in which a transparent electrode 11, an outgoing wiring 18, an external connection terminal 12, and an alignment film 14 are formed on a surface thereof. When the rubbing treatment is performed after the transparent electrode 11, the lead wiring 18, the external connection terminal 12, and the alignment film 14 are formed on the surface of the liquid crystal panel substrate 10, hairs are dense on the circumferential surface. While rotating the rubbing roller 15 wound around the cloth (rubbing sheet), as shown in Fig. 7, the surface of the liquid crystal panel substrate 10 is rubbed obliquely. According to the hair 15 formed on the surface of this rubbing roller, a number of minute grooves are formed in the surface of the alignment film 14. 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 aligned in the formation direction of the groove.

By the way, in the said conventional rubbing process, since the part of the rubbing roller 15 contacts the surface of the external connection terminal part 13 or the lead-out wiring 18 as shown in FIG. 7, this external connection terminal part 13 is carried out. The hair 15a of the rubbing roller 15 comes into contact with the external connection terminal 12 or the lead wire 18 formed in the cutout layer, and as shown in FIG. 6, the shaving layer of the hair 15a adhered to the hair tip of the rubbing roller. The adherent 15b such as the cut layer of the alignment film 14 is removed by the side wall of the external connection terminal 12 or the lead wire 18. On the other hand, in the surface part of the rubbing roller 15 which is not in contact with the external connection terminal part 13 or the drawing wiring 18, the deposit 15b is not removed. Therefore, in the region A shown in FIG. 7 among the surfaces of the alignment film 14 in contact with the surface of the rubbing roller 15, the adhesion of the deposit 15b is less, whereas the zone B shown in FIG. 7 is shown. In this case, since many deposits 15b are attached to the surface of the alignment layer 14 and the rubbing state is stained as shown in the drawing, there is a problem that display staining occurs in the liquid crystal display area.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display panel and a manufacturing method thereof, and more particularly to a manufacturing technique in the case of performing a rubbing treatment on the inner surface of a liquid crystal panel substrate.

1 is a cross-sectional view showing the structure of a liquid crystal display of an embodiment according to the present invention.

Fig. 2 is a schematic plan view showing a state of performing a rubbing process in the same embodiment.

3 is an enlarged cross-sectional view (sectional view showing a state cut along the line III-III in FIG. 2) showing a state in which the rubbing treatment is performed in the same embodiment.

4 is an enlarged cross-sectional view showing the structure of a liquid crystal display of another embodiment according to the present invention;

5 is an enlarged cross-sectional view showing a structural example of a conventional liquid crystal display panel.

Fig. 6 is an enlarged cross sectional view (sectional view showing a state cut along the line V-V in Fig. 7) showing a state in which a rubbing process is performed in a conventional method for manufacturing a liquid crystal display panel.

7 is a schematic plan view showing a state in which a rubbing process is performed in a conventional method for manufacturing a liquid crystal display panel.

Accordingly, the present invention has been made to solve the above problems, and an object thereof is to provide a liquid crystal display panel and a method of manufacturing the same, which prevents uneven treatment by the rubbing roller during the rubbing process, thereby reducing display unevenness of the liquid crystal display.

Means to be solved by the present invention for solving the above problems include two liquid crystal panel substrates each having an applied electrode pattern in the liquid crystal display region on the inner surface, a liquid crystal layer disposed between the liquid crystal panel substrates, and the liquid crystal panel substrate. On an inner surface of at least one of the liquid crystal panel substrates, an outgoing wiring connected to the application electrode pattern and / or an external connection terminal portion connected to the outgoing wiring, and at least a part of the outgoing wiring and / or the external connection terminal portion It is a liquid crystal display panel provided with the insulating film which coat | covers the periphery of the said liquid crystal display area | region containing, and can reduce surface friction, and the alignment film which coat | covers the said liquid crystal display area | region.

According to this means, since the insulating layer is coated on at least part of the lead-out wiring and / or the external connection terminal of the periphery of the liquid crystal display region, and the surface friction of the coating part is reduced, Unevenness of the rubbing treatment on the resulting alignment film is reduced, so that a liquid crystal display panel having reduced display unevenness can be obtained.

In addition, the surface friction of the insulating layer is preferably lower than that of the lead wire and the external connection terminal, so that the influence on the surface of the alignment film of the member (rubbing roller, etc.) used for the rubbing treatment is reduced.

Further, the insulating layer and the alignment film may be formed so as not to overlap each other, or may be formed so as to overlap completely as described later, or may be formed so as to overlap a portion thereon.

In particular, when the insulating film is made of an acrylic resin, it is also easy to form a transparent film by forming an acrylic resin, and further, an insulating film having a low surface friction can be reliably obtained.

In this case, since the thickness of the insulating film is 100 to 200 GPa, even when the insulating film is formed of an acrylic resin having a low surface friction, the thickness of the insulating film is small and the adhesion of the insulating film is less likely to be reduced, so that peeling of the liquid crystal display panel can be prevented. have.

In addition, a color filter is formed on the inner surface of one of the liquid crystal panel substrates, and when the insulating film covers the surface of the color filter as a protective film, unevenness of the rubbing treatment can be prevented by the insulating film serving as the protective film of the color filter. Therefore, an increase in the number of manufacturing steps can be suppressed.

Further, a color filter is formed on the inner surface of the other liquid crystal panel substrate, and when the insulating film covers the surface of the color filter as a protective film, it is possible to prevent smearing of rubbing treatment by an insulating film which also serves as a protective film of the color filter. As a result, an increase in the number of manufacturing steps can be suppressed. In addition, since the surface friction of the insulating film around the alignment film formed on the inner surface of the other liquid crystal panel substrate is low, the quality of rubbing process can be expected, and at the same time, the color filter is made of the same material as the insulating film of one liquid crystal panel substrate. Since a protective film can be formed, material management becomes easy and an increase in manufacturing cost can be suppressed.

Next, as a manufacturing method of a liquid crystal display panel, the extraction wiring connected to the applied electrode pattern formed in the liquid crystal display area | region on the inner surface of at least one liquid crystal panel substrate among two liquid crystal panel substrates for interposing a liquid crystal layer, and And / or forming an external connection terminal portion, thereafter, an insulating film which covers a periphery of the liquid crystal display region including at least part of the lead-out wiring and / or the external connection terminal portion, and which can reduce surface friction; Forming an alignment film covering the liquid crystal display region, and then performing a rubbing treatment on the inner surface of the liquid crystal panel substrate.

In the above case, when the insulating film and the alignment film are formed so as not to overlap with each other, any one of the insulating film and the alignment film may be formed first.

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

It is also possible to form the alignment film on the surface of the insulating film in the liquid crystal display region after the insulating film is formed almost all over the inner surface of the liquid crystal panel substrate. In this case, since the insulating film is formed almost on the entire surface of the liquid crystal panel substrate, no selective formation or patterning process is required, so that the spin coating method and the like can be easily formed and the number of steps can be reduced.

Next, the Example of the manufacturing method of the liquid crystal display panel which concerns on this invention is described with reference to an accompanying drawing. 1 is an enlarged cross-sectional view showing a partial structure of a color liquid crystal display panel formed by this embodiment, FIG. 2 is a plan view showing a state of a rubbing treatment process of the same panel, and FIG. 3 shows a state of a rubbing treatment process of the same panel. It is an enlarged sectional view shown.

In this embodiment, a transparent electrode 11 is formed for each pixel region in a portion that becomes a liquid crystal display region on the inner surface of the liquid crystal panel substrate 10. Further, by depositing aluminum and other metal materials, a plurality of lead wires 18 conductively connected to the transparent electrode 1 are formed to extend outward in the liquid crystal display region. In addition, an external connection terminal 12 conductively connected to the front end of the lead wire 18 is formed outside the liquid crystal display region. The thickness of the external connection terminal 12 is about 1000-2000 kPa normally.

On the inner surface of the liquid crystal panel substrate 10 in which the transparent electrode 11, the lead wiring 18, and the external connection terminal 12 were formed, the acrylic thermosetting resin was apply | coated thinly to the whole surface by the spin coat method, and suitable heating for a resin material is carried out. Curing is carried out under the conditions, and finally the transparent insulating film 16 is formed so that the film thickness is about 100 to 200 GPa. Next, a polyimide resin is coated in the liquid crystal display region on the surface of the transparent insulating film 16 and baked to form an alignment film 14 having a thickness of 700 to 800 kPa.

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

As described above, the liquid crystal panel substrates 10 and 20 having a layer structure formed on the inner surface thereof have rubbing treatments shown in FIGS. 2 and 3 (the processing state of the liquid crystal panel substrate 10 is shown in the drawing). Is done. There are various methods of this rubbing process. In this embodiment, a rubbing roller 15 having a plurality of hairs 15a on its surface is wound around a cylindrical roller. Then, in a state where the rubbing roller 15 is pressed against the liquid crystal panel substrate 110 at a predetermined pressure, the contact surface of the liquid crystal panel substrate is rotated in a rotational direction in which the rubbing roller 15 rotates in the same direction as the moving direction of the rubbing roller 15. While rubbing the inner surface of the liquid crystal panel substrate 10, the rubbing roller is moved.

The transparent insulating film 16 is formed to be extremely thin with respect to the thickness of the external connection terminal 12 or the lead-out wiring 18, but the irregularities and protrusions present on the surfaces of the external connection terminal 12 and the lead-out wiring 18 are present. Since the transparent insulating film 16 is made of acrylic resin, the surface friction is lower than that of the lead-out wiring 18 and the external connection terminal 12. Therefore, when rubbing is performed by the rubbing roller 15, the shaving layer of the hair 15a is generated between the hair 15a and the external connection terminal 12 or the lead wire 18, or by contact with the alignment film of the previous step. Only the portion of the generated aviation membrane material or the layer of the hair 15a itself is in contact with the external connection terminal 12 or the lead-out wiring 18 is removed by the side wall of the external connection terminal 12 or the lead-out wiring 18. As a result, no situation arises, and as a result, a uniform rubbing process can be performed on the alignment film 14 in the liquid crystal display region.

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

Next, as shown in FIG. 1, the liquid crystal panel substrate 10 and the liquid crystal panel substrate 20 are adhered through a sealing material 30 made of an ultraviolet curable resin or the like in a state of facing the inner surfaces on which the alignment films are formed. . The sealing material 30 is formed in a frame shape so as to surround the liquid crystal display region, and the liquid crystal sealing region is formed by adhering the liquid crystal panel substrates 10 and 20. A part of the sealing material 30 is previously taken out so that a sealing opening may be formed in the liquid crystal sealing region.

Finally, the liquid crystal 31 is injected from the sealing opening and the sealing opening is sealed to form a liquid crystal display panel supporting the liquid crystal layer. Thereafter, a part of the liquid crystal panel substrate is cut off, the external connection terminal portion is exposed, and the transparent insulating film 16 covering the surface is removed by plasma etching or the like. When many liquid crystal display parts are integrally formed, each liquid crystal display part is cut | disconnected.

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 lead wires are present at the outer edge of the liquid crystal display region. Therefore, rubbing unevenness resulting from the lead-out wiring can be prevented.

Here, the external connection terminal portion may be formed on the liquid crystal panel substrate 20 side without providing the external connection terminal portion in the liquid crystal panel substrate 10. In addition, you may provide an external connection terminal part to both board | substrates 10 and 20 simultaneously. In the above case, since the transparent insulating films 16 and 23 are formed on either of the liquid crystal panel substrates 10 and 20, even when the external connection terminal portion is formed on either of the substrates, as in the case described above. Unevenness of the rubbing treatment of the alignment film can be prevented.

The transparent insulating films 16 and 23 are not limited to the above materials as long as surface friction can be reduced than the external terminal portion 13, and may be other materials. In addition, when manufacturing the liquid crystal panel which comprises a reflection type liquid crystal display body, you may form an insulating film which is not transparent in the board | substrate of a reflection side (especially a reflection electrode is formed instead of a transparent electrode).

The thickness of the transparent insulating film is preferably 200 kPa or less in order to secure the adhesion between the liquid crystal panel substrate and the sealing material in the above material, and preferably 100 kPa or more as a thickness that can be easily formed by the spin coating method. When the transparent insulating film is thicker than 200 kPa, the adhesiveness is lowered, and there is a high possibility that peeling between substrates occurs in the liquid crystal panel.

In general, since the adhesion is low in the film with low surface friction, even when a film of another material is used instead of the transparent insulating film, it is meaningful to reduce the thickness and increase the adhesion to prevent the liquid crystal panel substrate from peeling off. In the present invention, in order to form a film having a particularly low surface friction, even when the film is considerably thinner than the thickness of the external connection terminal, it is effective in preventing rubbing of the rubbing treatment. The adhesiveness with respect to the liquid crystal panel board | substrate of the formed film itself is mentioned. It is preferable that it is 5 to 50% or less of the thickness of an external terminal part as a film thickness to form.

In the conventional manufacturing process of the liquid crystal display panel, while the display unevenness due to the unevenness of the rubbing treatment occurs at a rate exceeding almost 90% by a difference in degree, the insulating film is about 150 to 190 kPa in the above-described embodiment. In the liquid crystal panel substrate formed and manufactured in the range of, the observable display unevenness caused by the rubbing treatment was reduced to 10% or less. For this reason, the product cost with respect to the raw material in a manufacturing process drastically increased, and the display quality as a final product also improved significantly.

Moreover, in the said Example, although the transparent insulating film is apply | coated and formed in the whole inner surface of a liquid crystal panel board | substrate, you may form an insulating film in the periphery of the liquid crystal display area containing at least the lead wiring and an external terminal part in order to acquire the same effect. Also in the above case, since the periphery of the alignment film is uniformly covered by the insulating film, it is possible to prevent the unevenness of the rubbing process in the same manner.

4 illustrates a cross-sectional structure of a liquid crystal display panel according to another embodiment different from the above. In this embodiment, the same reference numerals are given to the same parts as the above embodiment, and the description thereof is omitted. In this embodiment, the external connection terminal 12 is provided at the distal end of the lead wire 18 connected to the transparent electrode 11 as in the above embodiment, but the insulating film (only on the liquid crystal display region and the lead wire 18) is used. 16) is formed, and an insulating film is not formed on the external connection terminal 12, and differs.

In this embodiment, by arranging the outer circumferential portion 16a of the insulating film on the lead-out wiring 18, rubbing unevenness due to the external connection terminal 12 cannot be prevented, but the liquid crystal display is more effective than the external connection terminal 12. It is possible to prevent rubbing unevenness caused by the lead-out wiring 18 formed in a portion close to the region, and at the same time, it is not necessary to remove the insulating film on the external connection terminal 12 later.

Thus, the effect by this invention is exhibited by covering the periphery of the liquid crystal display area | region containing at least one part of an outgoing wiring or an external connection terminal with the insulating film mentioned above. For example, an insulating film such as the transparent insulating films 16 and 23 may be formed only on the lead wiring 18 as shown in FIG. Alternatively, for example, the external connection of the side (upper side of the liquid crystal display region in FIG. 2) in which the rubbing process by the rubbing roller 15 shown in FIG. 2 is first performed in the periphery of the liquid crystal display region. Only the terminal 12 or the lead-out wiring 18 may be covered with an insulating film. This is because the rubbing process on the liquid crystal display area by the rubbing roller 15 is not affected by the lead wires 18 and the external connection terminals 12 formed below the liquid crystal display area shown in FIG. 2.

As described above, according to the present invention, since the surface friction is reduced by coating the insulating layer on the lead-out wiring and / or a part of the external connection terminal of the periphery of the liquid crystal display region, contacting the lead-out wiring and / or the external connection terminal is performed. The resulting unevenness of the rubbing treatment can be reduced, thereby reducing the uneven display of the liquid crystal display panel. Therefore, while the display quality of a liquid crystal display panel improves, the product cost with respect to the raw material at the time of manufacture of a liquid crystal display panel can be raised.

Claims (12)

Two liquid crystal panel substrates each having an applied electrode pattern in the liquid crystal display region on the inner surface thereof; A liquid crystal layer disposed between the liquid crystal panel substrates; An outgoing wiring connected to said application electrode pattern or an external connection terminal portion connected to said outgoing wiring on at least one of said liquid crystal panel substrates of said liquid crystal panel substrate; An insulating film covering a periphery of said liquid crystal display region including at least part of said lead-out wiring or said external connection terminal portion, and capable of reducing surface friction; An alignment film which covers the said liquid crystal display area | region is provided, The liquid crystal display panel characterized by the above-mentioned. The liquid crystal display panel according to claim 1, wherein the insulating film is made of acrylic resin. The liquid crystal display panel according to claim 2, wherein the insulating film has a thickness of 100 to 200 GPa. The liquid crystal display panel according to claim 1, wherein a color filter is formed on an inner surface of one of said liquid crystal panel substrates, and said insulating film covers the surface of said color filter as a protective film. 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 the surface of the color filter with a protective film. Forming a lead-out wiring or an external connection terminal portion connected to an application electrode pattern formed in the liquid crystal display region on at least one of the liquid crystal panel substrates of the two liquid crystal panel substrates for interposing the liquid crystal layer; Thereafter, forming an insulating film covering the periphery of the liquid crystal display area including at least a part of the lead-out wiring or the external connection terminal part and reducing the surface friction, and an alignment film covering the liquid crystal display area; , Thereafter, performing a rubbing treatment on the inner surface of the liquid crystal panel substrate. The method of manufacturing a liquid crystal display panel according to claim 6, further comprising removing an insulating film covering said external connection terminal portion after said step of performing a rubbing process. The method for manufacturing a liquid crystal display panel according to claim 6, wherein the insulating film is formed almost on the entire 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. The method of claim 6, wherein the insulating layer is made of acrylic resin. The method of manufacturing a liquid crystal display panel according to claim 9, wherein the insulating film has a thickness of 100 to 200 kPa. The method for manufacturing a liquid crystal display panel according to claim 6, wherein a color filter is formed on an inner surface of one of said liquid crystal panel substrates, and said insulating film is formed as a protective film on the surface of said color filter. The method for manufacturing a liquid crystal display panel according to claim 6, wherein a color filter is formed on an 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.