JP2004258192A - Rubbing roll and liquid crystal display element with alignment layer treated by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubbing roll with which an alignment layer formed on a substrate of a liquid crystal display element is treated with a uniform pressure coping with upsizing of the liquid crystal display element, for which dust control measures are taken and weight saving is performed and the liquid crystal display element with the alignment layer treated by using the same with excellent display quality. <P>SOLUTION: An external cylinder formed of stainless steel 43 with an applied plating layer 44 is fixed to an outside of a carbon fiber reinforced plastics 41 forming a cylinder shape with an adhesive 42. The rubbing roll is constructed by sealing both end parts of the roll with a multilayer construction comprising a rubbing cloth 46 stuck to a surface of the plating layer 44 with a conductive adhesive 45 with a stainless steel plate 48 with stainless steel flanges 47 provided thereon. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a rubbing roller used in an alignment treatment step, which is one of the steps for manufacturing a liquid crystal display element, and a liquid crystal display element that has been subjected to an alignment treatment using the rubbing roller.
[0002]
[Prior art]
The basic structure of a liquid crystal display element consists of two elements: a switching element and an electrode that control the alignment of liquid crystal molecules by applying a voltage to the surface, and an alignment film that gives a pretilt angle to the liquid crystal molecules on the upper surface. A liquid crystal display element substrate is fixed with a sealing material at a distance by a scattered spacer so that switching elements and electrodes face each other with an alignment film interposed therebetween. A liquid crystal layer is provided in a portion surrounded by the sealing material and the two liquid crystal display element substrates, and a polarizing plate is provided on the outer surface of each liquid crystal display element substrate. In the structure of such a liquid crystal display element, the alignment film is made of an organic polymer film such as a polyimide resin, and the surface of the alignment film is subjected to an alignment treatment such as rubbing with a polyamide synthetic fiber (rubbing). A predetermined orientation is given to the molecule.
[0003]
As shown in FIG. 1, a rubbing device used for such an alignment treatment is a liquid crystal display element while rotating a rubbing roller 2 in which a rubbing cloth material 22 is adhered to a cylindrical metal roller 21 in the direction of an arrow. In some cases, the surface of the alignment film 13 formed on the substrate 1 is rubbed in one direction, thereby regulating the molecular arrangement direction of the liquid crystal layer provided between the two liquid crystal display element substrates in the rubbing direction ( For example, see Patent Document 1.)
[0004]
[Patent Document 1]
JP-A-5-88179 (page 2-3, FIG. 3)
[0005]
[Problems to be solved by the invention]
In the alignment processing step of the liquid crystal display element, the distribution of the liquid crystal molecules is made uniform by rubbing the alignment film with a rubbing cloth, and the alignment is aligned in the same direction, so that a uniform display is performed over the entire surface of the liquid crystal display element. The purpose is to do so. By the way, in recent years, the size of liquid crystal display devices has been increasing, and those having a vertical and horizontal dimension of 1100 mm or more have been commercialized. Accordingly, a rubbing roller used in a rubbing device in an alignment process has also become large. Has been planned. In this case, as shown in FIG. 2, in a conventional rubbing roller 31 using a metal roller, as the length of the cylinder becomes longer, the central portion in the longitudinal direction of the rubbing roller is bent by its own weight, and the liquid crystal display element substrate is bent. The alignment film 33 formed on the substrate 32 is rubbed with non-uniform pressure. As a result, the uniformity of the display on the entire surface of the liquid crystal display element is lost, and the display quality is impaired. Also, if the rubbing roller is made of a metal roller with a rubbing cloth bonded with a normal adhesive, the rubbing roller rotates and the rubbing cloth rotates to generate static electricity due to friction between the rubbing cloth and the alignment film. The pile or the like which has fallen off the rubbing cloth is adsorbed on the alignment film, and the existence of the liquid crystal is hindered at that portion, so that the display has a portion such as a pinhole.
[0006]
The present invention has been made in view of the above problems, and in the alignment treatment step, which is one of the manufacturing steps of a liquid crystal display element, the liquid crystal display element can be uniformly formed over the entire surface of the liquid crystal display element substrate even when the liquid crystal display element is enlarged. A rubbing roller capable of rubbing the alignment film with an appropriate pressure and performing an alignment process so that dust and piles are not attracted to the alignment film of the liquid crystal display element substrate by static electricity during rubbing, and the alignment using the rubbing roller. Provided is a processed liquid crystal display element having high display quality.
[0007]
[Means for Solving the Problems]
In order to solve the above problem, the invention described in claim 1 of the present invention is directed to a liquid crystal display element substrate in which an alignment film is formed so as to cover a switching element or an electrode provided on the surface. A rubbing roller used in a film orientation treatment step, wherein the rubbing roller has a cylindrical shape, and at least carbon fiber reinforced plastic is used.
[0008]
The invention described in claim 2 of the present invention is characterized in that, in claim 1, the rubbing roller is formed by plating stainless steel on a member forming an outer cylinder of the carbon fiber reinforced plastic. Is what you do.
[0009]
According to a third aspect of the present invention, in the second aspect, the rubbing roller is configured such that a rubbing cloth is adhered to a surface of a plating applied to the stainless steel with a conductive adhesive. It is a feature.
[0010]
Further, the invention described in claim 4 of the present invention is characterized in that the alignment treatment is performed using the rubbing roller according to any one of claims 1 to 3.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to FIGS. 3 and 4 (the same parts are denoted by the same reference numerals). The embodiment described below is a preferred specific example of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention particularly limits the present invention in the following description. The embodiments are not limited to these embodiments unless otherwise described.
[0012]
FIG. 3 is a longitudinal sectional view of a rubbing roller showing an embodiment of the present invention, and FIG. 4 is a partial sectional view of an AA part of FIG. FIG. 3 shows a cross section orthogonal to the longitudinal direction of the rubbing roller 40 used in the alignment film alignment process of the liquid crystal display element substrate on which the alignment film is formed so as to cover the switching elements or electrodes provided on the surface. As shown, it is concentric, and the concentric innermost cylindrical portion serving as the core base material of the rubbing roller is formed of carbon fiber reinforced plastic 41, and is the portion that contributes most to the weight reduction of the rubbing roller. is there.
[0013]
A stainless steel 43 (specifically, SUS304) having a thickness of about 0.5 mm to 0.7 mm is provided in the outer cylindrical portion in a cylindrical shape, and the carbon fiber reinforced plastic 41 and the stainless steel 43 in the inner cylindrical portion are provided. It is bonded with an adhesive 42 such as an epoxy resin. Further, on the surface of the stainless steel 43, a plating layer 44 of nickel or chromium having a thickness of about 50 μm is provided, on which a rubbing cloth 46 is adhered by a conductive adhesive 45 to reduce the electric contact resistance. It is planned. As a result, an electric path for discharging static electricity generated by friction between the rubbing cloth and the alignment film due to the rotation of the rubbing roller is formed, so that static electricity is not accumulated, and dust floating in the air and piles falling off from the rubbing cloth are formed. Can be prevented from adsorbing to the alignment film. In this embodiment, SUS304 is used for the stainless steel 43 and nickel or chromium is used for the plating material. However, the present invention is not limited to this, and may be appropriately determined in consideration of functions, workability, cost, and the like. Things.
[0014]
Further, both end surfaces of the rubbing roller are covered with a stainless steel plate 48 to which a stainless steel flange 47 for transmitting the rotational force during rubbing and discharging static electricity generated when the alignment film is rubbed to the outside is attached. And the carbon fiber reinforced plastic 41 is covered. For this reason, a force is not directly applied to the carbon fiber reinforced plastic during the rotation of the rubbing roller, and mechanical strength is secured, and at the same time, an electric path for discharging static electricity to the outside is formed.
[0015]
The surface of the carbon fiber reinforced plastic 41 may be plated with nickel or chromium to enhance the mechanical strength of the carbon fiber reinforced plastic. In this case, by bonding the plated carbon fiber reinforced plastic and the stainless steel 43 with a conductive adhesive, it is possible to further reliably secure a static electricity discharge path. Although nickel or chromium is used as the plating material, the present invention is not limited to nickel or chromium, and may be determined as appropriate in consideration of functions, workability, cost, and the like.
[0016]
【The invention's effect】
Conventionally, rubbing rollers using aluminum as a roller for attaching a rubbing cloth, which is generally performed, and a rubbing roller using the carbon fiber reinforced plastic of the present invention are compared below in terms of weight and deflection value. Show. The comparative sample has dimensions of 140 mm in outer diameter, 7.5 mm in wall thickness, and 2400 mm in length, and is made of carbon fiber reinforced plastic having a specific gravity of 1.7, a weight of 21.5 kg, a specific gravity of 2.7, and a weight of 28. The rubbing roller of the present invention shown in FIG. 3 and the conventional rubbing roller using aluminum for the roller shown in FIG. 5 were used. As a result, the weight of the rubbing roller using the carbon fiber reinforced plastic of the present invention is reduced by about 25 to 40% as compared with the conventional rubbing roller using aluminum. At equal load, the rubbing roller using carbon fiber reinforced plastic is 0.021 mm, the one using aluminum is 0.078 mm, and the rubbing roller using carbon fiber reinforced plastic is about 1/3 to 1 of that using aluminum. It can be seen that the weight is reduced to / 4.
[0017]
Therefore, the rubbing roller using carbon fiber reinforced plastic is lighter in weight than the conventional rubbing roller using aluminum. Workability in moving is improved. In addition, as the size of the liquid crystal display element increases, the rubbing roller also needs to be increased in size. Uniformity is hardly impaired, and good display quality can be maintained even when the size of the liquid crystal display element is increased. Furthermore, since dust prevention measures have been taken to prevent static electricity generated during rubbing from being discharged and accumulated on the rubbing roller, the alignment film provided on the liquid crystal display element substrate is left in the air on the alignment film during the alignment process. Adsorption of floating dust, piles falling off from the rubbing cloth, and the like is reduced, and defects due to display defects of the liquid crystal display element are reduced, thereby improving the production yield. And many other effects.
[Brief description of the drawings]
FIG. 1 is described as FIG. 3 in Reference Document 1 (Japanese Patent Laid-Open No. 5-88179).
FIG. 2 is a schematic view showing a deflection of a general rubbing roller using an aluminum roller.
FIG. 3 is a longitudinal sectional view of the rubbing roller of the present invention.
FIG. 4 is a partial cross-sectional view taken along a line AA in FIG. 3;
FIG. 5 is a longitudinal sectional view of a general rubbing roller using an aluminum roller.
[Explanation of symbols]
40 rubbing roller 41 carbon fiber reinforced plastic 42 adhesive 43 stainless steel 44 plating layer 45 conductive adhesive 46 rubbing cloth

Claims (4)

A rubbing roller for use in an alignment treatment step of the alignment film of a liquid crystal display element substrate having an alignment film formed so as to cover a switching element or an electrode disposed on the surface, wherein the rubbing roller has a cylindrical shape. A rubbing roller comprising at least carbon fiber reinforced plastic. The rubbing roller according to claim 1, wherein a member forming the outer cylinder of the carbon fiber reinforced plastic is made of plated stainless steel. The rubbing roller according to claim 2, wherein the rubbing roller has a rubbing cloth adhered to a surface of the plating applied to the stainless steel with a conductive adhesive. A liquid crystal display device, wherein an alignment process is performed using the rubbing roller according to claim 1.

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