JP2005037740A - Rubbing device, and liquid crystal display element manufactured by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubbing device by which an alignment layer formed on a substrate of a liquid crystal display element is uniformly rubbed on the entire surface thereof and to provide the liquid crystal display element manufactured by using the rubbing device. <P>SOLUTION: A magnet plate 2 made to be a module by arranging a number of magnets 1 at equal intervals and guide rails 3 are disposed on the upper surface of a fixed bed 4 so that the guide rails 3 are positioned on the both sides holding the magnet plate 2 to be parallel to the magnet plate 2. A coil plate 7 made to be a module by arranging air-coiled cores (not figured) so as to be opposed to the magnets 1 is provided at a center part of a stage 6 formed integrally with sliders 5 sliding along the guide rails 3, a table 9 placing the substrate 8 of the liquid crystal display element on which the alignment layer is formed is fixed onto the upper surface of the stage 6 and a rubbing roller 11 to which a rubbing cloth 10 is attached is rotatably disposed on the upper side thereof. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rubbing apparatus for rubbing an alignment film formed on a liquid crystal display element substrate under uniform conditions in an alignment process which is one of the manufacturing processes of a liquid crystal display element, and a liquid crystal display element manufactured using the same. .

  The basic structure of a liquid crystal display element is a two-sheet structure in which switching elements and electrodes that control the alignment of liquid crystal molecules by applying a voltage are formed on the surface, and an alignment film that gives a pretilt angle to the liquid crystal molecules is formed on the upper surface. The liquid crystal display element substrate is fixed with a sealing material at intervals with dispersed spacers so that the switching elements and the electrodes face each other through the alignment film. A liquid crystal layer is provided in a portion surrounded by the two liquid crystal display element substrates and the sealing material, and a polarizing plate is provided outside each of the liquid crystal display element substrates. In such a structure of the liquid crystal display element, the alignment film applied to the liquid crystal display element substrate is formed of an organic polymer film such as a polyimide resin, and the surface of the alignment film is rubbed in a certain direction with a polyamide synthetic fiber. (Rubbing) An alignment process is performed in which liquid crystal molecules are aligned (pretilted) along the grooves by forming fine grooves.

  In such an alignment process, the alignment film is rubbed by attaching a rubbing cloth in which piles (hairs) are planted on the outer peripheral surface of a cylindrical roller to form a rubbing roller, and the liquid crystal display element substrate in a certain direction. The alignment film formed on the liquid crystal display element substrate is rubbed with a rotating rubbing roller pile while moving at a constant speed.

  In this case, as a method of moving the liquid crystal display element substrate, two guides are arranged in parallel on a surface plate, and a ball screw screwed to a feed screw provided below the stage on which the liquid crystal display element substrate is placed. Is arranged in parallel with the guide at an intermediate position between the guides with one end connected to the motor. When the ball screw is rotated by driving the motor, the stage on which the liquid crystal display element substrate is placed moves horizontally and linearly with respect to the surface plate while being guided to the two guides via the feed screw. (For example, refer to Patent Document 1).

In addition, as a method of rotating and supporting the rubbing roller, a concave portion is provided at a position that becomes the rotation center of both ends of the rubbing roller, and the front end portion of the support body having a conical tip portion and a rear end portion connected to the motor is the rubbing roller Is fitted into and fixed to a recess at one end of the rubbing roller to transmit rotational power to the rubbing roller, and a recess provided at the other end of the rubbing roller is supported by a bearing whose rear end is held by a bearing. There is a mechanism that fits and supports the tip (see, for example, Patent Document 2).
JP 2000-19520 A (page 4-5, FIG. 1) Japanese Patent Laid-Open No. 10-142607 (page 3-4, FIG. 1)

  The alignment treatment process of the liquid crystal display element substrate is performed by rubbing the alignment film in direct contact with the liquid crystal molecules with a rubbing cloth (pile thereof) so that the distribution of the liquid crystal molecules is uniform and the alignment is aligned in the same direction. The purpose is to perform uniform display over the entire surface. By the way, in recent years, liquid crystal display elements have a tendency to increase in size, and accordingly, a multi-faced glass substrate in which a plurality of liquid crystal display element substrates are formed on a single glass substrate (also referred to as a liquid crystal display element substrate in this case). Is also larger.

The size of the multi-chamfered glass substrate on which the liquid crystal display element substrate is multi-determined is determined by the size of each liquid crystal display element substrate, the number of multi-chamfering and the processing capacity of the device, etc. The first generation of liquid crystal was about 300 mm x 400 mm, but it is about 1500 mm x 1800 mm in the current 6th generation liquid crystal generation, and about 1800 mm x 2000 mm in the future seventh generation. Expected to be. For reference, Table 1 shows the relationship between the liquid crystal generation and the glass size.

By the way, with the increase in size of the liquid crystal display element substrate, it is necessary to lengthen the rubbing roller used in the rubbing apparatus in the alignment process. In that case, as the cylinder length of the rubbing roller is increased, the central portion in the longitudinal direction is bent by its own weight, and the entire alignment film formed on the liquid crystal display element substrate cannot be rubbed with uniform pressure. As a result, the entire surface of the liquid crystal display element shows a non-uniform display, resulting in a display element with poor appearance and impaired display quality. Further, in the alignment processing step, the alignment film formed on the liquid crystal display element substrate is rubbed with a rotating rubbing roller while moving the table on which the liquid crystal display element substrate is mounted. The movement method using a ball screw drive mechanism using a motor as a drive source is an indirect drive system that converts the rotational movement of the ball screw into a linear movement of the table. In the motor or in the ball screw 1) The backlash occurs due to the engagement error and wear of the ball screw and the feed screw, which causes vibration.
2) Dust and noise are generated by contact between the ball screw and the feed screw.
3) Noise is generated from the motor that drives the ball screw.
4) As the ball screw becomes longer, the ball screw sways due to distortion and deflection.
5) At the same time as the vibration around the flare by the both-end support portions of the ball screw, the natural frequency changes as the table moves, and the vibration mode changes. It is difficult to take measures against vibration over the entire length of the table in such a non-constant vibration mode.
This causes problems such as non-uniform rubbing on the alignment film, which is a cause of generation of a liquid crystal display element that deteriorates display quality.

  The present invention has been devised in view of the above problems, and in the alignment treatment process, which is one of the manufacturing processes of a liquid crystal display element, the liquid crystal display element substrate can be uniformly applied over the entire surface of the liquid crystal display element substrate. A rubbing apparatus ingeniously devised on the stage moving mechanism on which the liquid crystal display element substrate on which the alignment film has been placed and the support mechanism for the rubbing roller to which the rubbing cloth is attached, so that the alignment film can be rubbed with an appropriate pressure It is an object of the present invention to provide a liquid crystal display element with high display quality manufactured using the rubbing apparatus.

  In order to solve the above-mentioned problem, the invention described in claim 1 of the present invention is such that a rubbing cloth is attached to an outer peripheral surface of a stage on which a liquid crystal display element substrate on which an alignment film is formed and a cylindrical roller are mounted. A rubbing apparatus that rubs the surface of the alignment film with a rotating rubbing roller while moving the stage, and the stage includes a large number of magnets arranged linearly on a fixed portion. And a coil arranged in the movable part, the linear movement is performed by a linear motor drive of a mechanism that moves the movable part by the thrust of the magnetic force generated by the magnetic part.

  According to a second aspect of the present invention, there is provided a stage on which the liquid crystal display element substrate on which the alignment film is formed, and a rubbing roller having a rubbing cloth attached to the outer peripheral surface of the cylindrical roller. And a rubbing device for rubbing the surface of the alignment film with a rotating rubbing roller while moving the stage, and the tip of the support that supports the rubbing roller at both ends of the rubbing roller is substantially at the tip. In the truncated cone, the tip of the support is fitted into recesses provided at both ends of the rubbing roller so as to rotatably support the rubbing roller.

  According to a third aspect of the present invention, there is provided a stage on which a liquid crystal display element substrate on which an alignment film is formed, and a rubbing roller having a rubbing cloth attached to the outer peripheral surface of a cylindrical roller. And a rubbing device for rubbing the surface of the alignment film with a rotating rubbing roller while moving the stage, wherein the stage is arranged in a large number of magnets arranged linearly in a fixed part and a movable part. The shape of the support that moves linearly by the linear motor drive of the mechanism that moves the movable part by the thrust of the magnetic force generated by the coil and that supports the rubbing roller at both ends of the rubbing roller is the tip. The portion is a substantially truncated cone, and the tip of the support is fitted into the recesses provided at both ends of the rubbing roller so that the rubbing roller is rotatably supported. It is characterized in that the.

  According to a fourth aspect of the present invention, there is provided the liquid crystal display element substrate according to any one of the first to third aspects, wherein both the vertical and horizontal dimensions are 1500 mm or more. The alignment film can be rubbed at once.

  Moreover, the invention described in claim 5 of the present invention is characterized by being manufactured using the rubbing apparatus according to any one of claims 1 to 4.

  Hereinafter, the best mode of the present invention will be described in detail with reference to FIG. 1 to FIG. 6 (the same parts are given the same reference numerals and the description thereof will be omitted). The embodiments described below are preferable specific examples 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. As long as there is no description of the effect, it is not restricted to these aspects.

  1 is a front view of the best mode of the rubbing apparatus according to the present invention, FIG. 2 is a side view, FIG. 3 is a plan view, FIG. 4 is a cross-sectional view taken along the line AA in FIG. FIG. 6 is an explanatory view showing the relationship between the rubbing roller support mechanism and the amount of bending of the rubbing roller.

  A magnet plate 2 and a guide rail 3, which are formed by arranging a plurality of magnets 1 by alternately changing the polarities of adjacent magnetic poles and arranged at equal intervals, are guided in parallel to the magnet plate 2 on both sides of the magnet plate 2. With the rail 3 positioned, it is arranged on the upper surface of the fixed bed 4. A coil plate 7 that is modularized by arranging an air core coil (not shown) so as to face the magnet 1 at the center of the stage 6 integrated with the slider 5 that slides along the guide rail 3. The linear motor driving mechanism is configured by the opposed magnet 1 and the air-core coil. Further, a table 9 on which the liquid crystal display element substrate 8 having an alignment film formed thereon is fixed on the upper surface of the stage 6 is fixed to the stage 6, and a rubbing roller 11 to which a rubbing cloth 10 is attached is placed on the table 9. It arrange | positions in the state which can be rotated above the liquid crystal display element substrate 8 so that the placed liquid crystal display element substrate 8 may be rubbed. Although not shown, a linear scale for detecting the position of the stage 6 is provided on the upper surface of the bed 4 and outside the guide rail 3 to perform feedback control.

  In order to perform rubbing with the rubbing apparatus having such a configuration, the setting position of the rubbing roller 11 is adjusted so as to come into contact with the liquid crystal display element substrate 8 placed on the table 9 with a predetermined pressure, and then starts rotating at a constant speed. Let On the other hand, the table 9 on which the liquid crystal display element substrate 8 is placed corresponds to the relationship between the position and polarity of the opposing magnet 1 in the direction of the current flowing in the air-core coil provided on the stage 6 to which the table 9 is fixed. The slider 5 is slid along the guide rail 3 and moved linearly by a linear motor drive that generates a linear motion by controlling the movement. That is, the alignment film (not shown) formed on the liquid crystal display element substrate 8 placed on the table 9 advances by moving at a constant speed in a certain direction while receiving the pressure of the rotating rubbing roller 11. Rubbing is continuously performed in the direction, and finally, alignment treatment is performed over the entire surface of the alignment film formed on the liquid crystal display element substrate 8.

  The rubbing quality of the alignment film cannot be evaluated until it is assembled into a liquid crystal display element using the rubbed liquid crystal display element substrate 8 and actually displayed. Therefore, the liquid crystal display element substrate 8 having a poor rubbing may flow to a subsequent process (sealing process, liquid crystal injection process, glass scribing process, etc.). In addition to spending man-hours, it also causes a decrease in yield. As described above, the rubbing step is an important part of the process of manufacturing the liquid crystal display element, and it is required to perform uniform rubbing with great care.

  Therefore, the rubbing apparatus according to the present invention employs a linear motor drive system having a configuration of the magnet 1 and an air core coil as a method of moving the liquid crystal display element substrate 8 during rubbing. Instead of the conventional mechanism that mechanically converts the rotational power of the ball screw into linear motion, a mechanism using a linear motor drive in which the movable part moves in a non-contact manner with the fixed part using thrust generated by magnetic force. In this way, all of the problems 1) to 5) described in the above “Problems to be solved by the invention” that occur during power conversion by a ball screw are solved.

Table 2 compares the amplitude of vibration between a rubbing apparatus that employs a conventional ball screw driving system and a rubbing apparatus that employs a linear motor driving system of the present invention. The moving speed of the table is set to 50 mm / s, and the actual measurement values are shown in μm units.

  From the measured amplitude values in Table 2, it can be seen that the amplitude of vibration applied to the stage 6 is smaller and smoother when the stage is moved by linear motor driving than by ball screw driving. Therefore, it is clear that the vibration applied to the liquid crystal display element substrate 8 placed on the table 9 fixed to the stage 6 is also smaller when moved by the linear motor drive. This means that the variation in the distance between the liquid crystal display element substrate 8 on which the alignment film is formed and the rubbing cloth 10 attached to the outer peripheral surface of the rubbing roll 11 is small. It shows that it is rubbed. Therefore, it has been confirmed that the linear motor drive is an effective method for uniformly rubbing the alignment film.

  Furthermore, as one of the requirements necessary for improving the uniformity of rubbing, it is possible to reduce the bending of the rubbing roller 11 having the rubbing cloth 10 attached to the outer peripheral surface as much as possible. When the rubbing roller 11 is bent, the distance between the liquid crystal display element substrate 8 and the rubbing cloth 10 varies depending on the location, and the pressure applied to the alignment film formed on the liquid crystal display element substrate 8 during rubbing varies depending on the location. This results in a non-uniform alignment process. In particular, when the rubbing roller is lengthened corresponding to the increase in size of the liquid crystal display element substrate 8, the rubbing roller is also greatly bent. In order to reduce this bending, a method of reducing the weight and increasing the rigidity of the rubbing roller 11 can be considered, but the bending can be reduced by optimizing the shape of the support 12 of the rubbing roller 11.

  The optimization of the shape of the support 12 of the rubbing roller 11 is shown in FIG. 5 as an enlarged partial sectional view of the support 12 of FIG. The support 12 has a substantially frustoconical shape so that the cross-sectional area of the cut surface by a plane whose tip is perpendicular to the center line 14 becomes smaller in the tip direction. On the other hand, a recess having substantially the same shape as the tip of the support 12 is provided at both ends of the rubbing roller 11, and the rubbing roller is rotatably supported by fitting the tip of the support into this recess. Yes.

  Here, the angle formed between the extension line 13 of the substantially truncated cone-shaped bus bar of the support 12 and the center line 14 is preferably between 10 ° and 20 °.

  The rubbing roller 11 is supported by support bodies 12 fitted to both ends of the rubbing roller 11, and the shapes of the support bodies 12 at both ends are the same. The part is fitted and fixed in the recess of the rubbing roller 11 and integrated, and the rear end part is connected to the drive part and plays a role of transmitting power to the rubbing roller 11 as a rotational motion. The other support body 12 also has a tip portion fitted in the recess of the rubbing roller 11, but is supported so that the rubbing roller can freely rotate.

  FIG. 6 shows values calculated by simulation of the relationship between the support mechanism of the rubbing roller 11 and the amount of bending of the rubbing roller 11 and measured values. The conditions of the simulation and the actual measurement are as follows. For the rubbing roller 11, the material is aluminum, the diameter is 150 mm, and the length is 2000 mm. As for the support mechanism of the support portion, (a) is supported at both ends of the rubbing roller 11, (b) is supported at both ends of the rubbing roller 11 and applied axial force, (c) is imperfectly fixed at both ends of the rubbing roller 11 and applied axial force. , (D) is fixing of both ends of the rubbing roller 11. Note that only (c) is actual measurement values, and other values are calculated by simulation. As a result, the maximum deflection amount of the support form (a) was 32 μm, (b) was 23 μm, (c) was 13 μm, and (d) was 7 μm. It is presumed that the pivot support structure (a ') of the conventional support form is a structure approximated to (a) of both ends support, and the support structure (d') of the present invention is a structure approximated to (d) of both ends fixed.

  Therefore, in the above-described four types of structures for supporting the rubbing roller 11, the bending of the rubbing roller 11 can be minimized by providing the support having the rigidity (more precisely, the bending moment rigidity) as in the support structure of the present invention. It became clear that it could be stopped. However, sufficient consideration must be given to the strength and rigidity of the support portion that can withstand the anti-bending moment generated at this time, and data must be accumulated through trial manufacture, experimentation and evaluation. The support 12 has a substantially truncated cone shape at the tip, and the intersection of the extended line 13 and the center line 14 of the substantially truncated cone is positioned at the rotation center of the end of the rubbing roller 11. Thereby, the rotation with less distortion of the rubbing roller 11 can be secured. Such a support structure according to the present invention exhibits a greater effect as the rubbing roller 11 becomes longer, and plays an important role in the future trend of increasing the size of the liquid crystal display element substrate 8. .

  As described above, the liquid crystal rubbing apparatus of the present invention is a table on which a liquid crystal display element substrate is placed in order to uniformly rub the alignment film formed on the liquid crystal display element substrate even when the liquid crystal display element is enlarged. Adopting a linear motor drive for the mechanism that moves the roller, mainly eliminates the cause of vibration, and further reduces the bending of the rubbing roller by making the tip of the rotating rubbing roller support body a substantially truncated cone Further, by improving the rubbing roller pressure applied to the alignment film by these two methods so as to be uniform, it is possible to perform highly uniform alignment treatment over the entire alignment film. As a result, the yield of the liquid crystal display element is improved, and an inexpensive liquid crystal display element can be realized. This is particularly effective for a liquid crystal display element substrate having a size of 1500 mm × 1500 mm or more. In this case, the manufacturing cost of the liquid crystal display element is smaller than that of a smaller one. Therefore, the production cost can be greatly improved by the yield improvement.

It is a front view of the best form of the rubbing apparatus concerning this invention. It is a side view of FIG. It is a top view of FIG. It is AA sectional drawing of FIG. It is a B section detailed sectional view of Drawing 1. It is explanatory drawing which shows the relationship between the support mechanism of a rubbing roller, and the deflection amount of a rubbing roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnet 2 Magnet plate 3 Guide rail 4 Bed 5 Slider 6 Stage 7 Coil plate 8 Liquid crystal display element board 9 Table 10 Rubbing cloth 11 Rubbing roller 12 Support body 13 Bus extension line 14 Center line

Claims (5)

A stage on which a liquid crystal display element substrate on which an alignment film is formed is mounted; and a rubbing roller having a rubbing cloth attached to an outer peripheral surface of a cylindrical roller, and the rubbing roller that rotates while moving the stage. A rubbing apparatus for rubbing the surface of an alignment film, wherein the stage moves the movable part by thrust of magnetic force generated by a large number of magnets arranged linearly on the fixed part and a coil arranged on the movable part. A rubbing apparatus which moves linearly by driving a linear motor of a mechanism. A stage on which a liquid crystal display element substrate on which an alignment film is formed is mounted; and a rubbing roller having a rubbing cloth attached to an outer peripheral surface of a cylindrical roller, and the rubbing roller that rotates while moving the stage. A rubbing apparatus for rubbing the surface of an alignment film, wherein the support for supporting the rubbing roller at both ends of the rubbing roller has a substantially truncated cone at the tip, and concave portions provided at both ends of the rubbing roller. A rubbing apparatus, wherein the rubbing roller is rotatably supported by fitting a tip end portion of the support. A stage on which a liquid crystal display element substrate on which an alignment film is formed is mounted; and a rubbing roller having a rubbing cloth attached to an outer peripheral surface of a cylindrical roller, and the rubbing roller that rotates while moving the stage. A rubbing apparatus for rubbing the surface of an alignment film, wherein the stage moves the movable part by thrust of magnetic force generated by a large number of magnets arranged linearly on the fixed part and a coil arranged on the movable part. The support is configured to move linearly by driving a linear motor of the mechanism and to support the rubbing roller at both ends of the rubbing roller. The support has a substantially truncated cone at the tip and is provided at both ends of the rubbing roller. A rubbing apparatus, wherein the rubbing roller is rotatably supported by fitting a tip portion of the support body into the recessed portion. 4. The alignment film formed on the liquid crystal display element substrate having both vertical and horizontal dimensions of 1500 mm or more can be collectively rubbed. 5. Rubbing equipment. A liquid crystal display element manufactured using the rubbing apparatus according to any one of claims 1 to 4.

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