WO2003100509A1

WO2003100509A1 - Method for producing liquid crystal display

Info

Publication number: WO2003100509A1
Application number: PCT/JP2002/005069
Authority: WO
Inventors: Nobuyoshi Nakagawa
Original assignee: Binit Corporation
Priority date: 2002-05-24
Filing date: 2002-05-24
Publication date: 2003-12-04
Also published as: JP3769576B2; CN1628261A; CN100376941C; KR20050003369A; JPWO2003100509A1; KR100760396B1; HK1079575A1

Abstract

A method for producing a liquid crystal display having a glass substrate, especially a liquid crystal display for thin mobile apparatus such as a portable telephone, at a low cost. The method for producing a liquid crystal display, wherein a large size cell (4) obtained by pasting a pair of mother glasses (1, 2) subjected to pretreatment of liquid crystal display is divided into a plurality of intermediate size cells (6) which are then subjected to thin plate machining to have the thickness of a product before being divided into small product size cells (7, 10). According to the production method, the thin plate polishing process can be performed efficiently and the cause of rejectable product can be eliminated.

Description

Specification

Manufacturing method of liquid crystal display device

The present invention relates to a method for manufacturing a liquid crystal display device having a glass substrate, and more particularly, to a method for manufacturing a liquid crystal display device suitable for mobile devices, portable devices such as mobile phones and audio devices. Background art

In recent years, there has been an increasing need for small, thin, and lightweight mopile and portable devices using liquid crystal.Recently, folding mobile phones have a sub-display on the outer surface to receive time and e-mail. The number of things that can be seen immediately, such as the presence or absence, is increasing. While such sub-displays require higher functionality, increasing the thickness of the sub-display will affect the overall thickness of the device, and demands for thinner displays (liquid crystal displays). It is getting higher.

Conventionally, as a method of manufacturing a liquid crystal display device used for a mopile device, for example, there is a method as shown in FIG. In this method, a pair of glass substrates (mother glass) having a size enough to obtain a large number of liquid crystal cells of a product size are prepared, and as pretreatments for liquid crystal display, formation of electrodes (not shown), formation of an alignment film, By performing processing and the like, the segment substrate 91 and the common substrate 92 are formed.

In the next step, as shown in FIG. 11, a seal 82 is printed on the outer peripheral area of the segment substrate 91 so as to correspond to a size that is later cut and processed into a liquid crystal cell of a product size. The outer peripheral seal 93 is formed by printing on the outer peripheral area of the segment substrate 91. Then, the segment substrate 91 and the common substrate 92 are bonded to each other to form a large-sized cell 96, which is fired at an appropriate temperature to cure the seal 82 and the outer peripheral seal 93. The seals 8 2 and the outer peripheral seal 93 have openings 83, 9 4 is provided to prevent air from leaking when the segment board 91 and the common board 92 are bonded together. After bonding, the opening 94 of the outer peripheral seal 93 is temporarily sealed with an epoxy resin or the like. This prevents foreign substances such as water and abrasives from entering the inside through a very narrow gap (usually) between the segment substrate 91 and the common substrate 92 in the next polishing step.

Next, at least one surface of the large-sized cell 96 is polished by adding a polishing agent with a polishing device, and the plate thickness is reduced from t0 to t1, whereby a thin large-sized cell 96a is formed. Is formed. In the thinning of the polishing process, for example, the plate thickness t 0 = 1.0 mm (0.5 mm on one side) of the large-sized cell 96 is changed to the plate thickness t 1 = 0 in the thin large-sized cell 96 a. Polished to about 6 mm (0.3 mm per side). However, further thinning is difficult because of the size of the mother glass, which tends to break easily.

Subsequently, the large-sized cell 96 thinned is cut into small-sized cells 97 that are product sizes. At this time, in the outer peripheral area, the outer peripheral seal 93 is discarded by cutting along a line 95 slightly inside the outer peripheral seal 93. Foreign matters such as abrasives that have entered the gap 93 a further outside the outer peripheral seal 93 are discarded together with the outer peripheral seal 93.

Then, the liquid crystal is injected into the small-sized cell 97 from the opening 83, the opening 83 is sealed, and the inside is protected by the seal 82 and polished again. As a result, the small-sized cell 97 is thinned to a plate thickness t2, and is finished into a liquid crystal cell 97a having a product thickness t2. In the thinning of the polishing step, for example, the small-sized cell 97 having a plate thickness t 1 = 0.6 mm (0.3 mm on one side) has a liquid crystal cell 97 a having a plate thickness t 2 = 0.3 mm. Polished to about 4 mm (0.2 mm per side).

As described above, the product is formed through two polishing steps, but in the second polishing step, foreign substances such as abrasives may enter the outer region 82 a of the seal 82. Since the terminal portion is formed in the region, the terminal portion becomes dirty and an operation failure is likely to occur. In addition, allowance is discarded in the area 8 2a outside the seal 82. Since there are no cracks, if cracks occur in the polishing process, it will be defective. In other words, the product yield deteriorates and production efficiency decreases. Therefore, there is a problem that such conventional production methods increase production costs.

In some cases, relatively thin glass is used without polishing in order to reduce costs.However, glass is likely to be deformed or damaged during transport, cleaning, and processing in the cell manufacturing process. However, ultra-thin glass cannot be used in the manufacturing process. In other words, there is a problem that an ultra-thin display cannot be produced and an ultra-thin product cannot be produced.

The present invention has been made in view of such problems, and it is possible to obtain a low-cost liquid crystal display device by eliminating a defective product by improving a polishing process for thinning a plate, thereby improving production efficiency. An object of the present invention is to provide a method for manufacturing a liquid crystal display device that can be used. Disclosure of the invention

According to the method for manufacturing a liquid crystal display device according to claim 1 of the present invention, a large size cell is divided into a medium size cell including a plurality of small size cells, and after being thinned in this state, a small size cell is formed. Is divided into Thinning is easy because of the medium-sized cell, and the thinning process is performed only once. In addition, in the thinning process, the outer peripheral portion containing foreign matter is discarded.

Further, according to the method of manufacturing a liquid crystal display device according to claim 2 of the present invention, a plurality of outer peripheral seals for a medium-sized cell are formed in a large-sized cell, and the opening thereof is adjacent to the outer peripheral seal for a medium-sized cell. It is provided on the side. Thus, when cut into medium-sized cells, a seal is formed in a state where polishing is possible, and the opening faces the cut surface.

According to the method of manufacturing a liquid crystal display device according to claim 3 of the present invention, a large-sized cell is thinned to an intermediate thickness and divided into medium-sized cells. As a result, the processing allowance for thinning in a medium-sized cell is reduced, and processing is facilitated. According to the method of manufacturing a liquid crystal display device according to claim 4 of the present invention, the space between the adjacent outer peripheral seals for medium-sized cells is sealed with a partial seal, and at least one of the openings is formed with an opening. It is said. As a result, the space between the mother and the glass is completely sealed, and polishing can be performed in a large-sized cell state.

Further, according to the method of manufacturing a liquid crystal display device described in claim 5 of the present invention, microcracks generated by scribing are completely removed, and even if the device is thin, it is hard to be damaged by a shock input or the like.

According to the method of manufacturing a liquid crystal display device according to claim 6 of the present invention, a large-sized cell is divided into moderately-sized medium-sized cells, and the next thinning step is facilitated.

Further, other objects and features of the present invention will be clarified in the following detailed description based on the accompanying drawings. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view illustrating a first example of an embodiment of a method for manufacturing a liquid crystal display device according to the present invention, and illustrating each manufacturing process.

FIG. 2 is a plan view showing a first example of an embodiment of a method for manufacturing a liquid crystal display device according to the present invention.

FIG. 3 is a flowchart of a manufacturing process showing a first example of an embodiment of a method of manufacturing a liquid crystal display device according to the present invention.

FIG. 4 is a plan view showing a process of a first example of an embodiment of a method of manufacturing a liquid crystal display device according to the present invention.

FIG. 5 is a partially enlarged view of a portion S in FIG.

FIG. 6 is a sectional view taken along line XX of FIG.

FIG. 7 is a sectional view showing a state immediately after the cutting in FIG.

FIG. 8 is a perspective view illustrating a second example of the embodiment of the method for manufacturing the liquid crystal display device according to the present invention, and illustrating each manufacturing process.

FIG. 9 is a second embodiment of the liquid crystal display device manufacturing method according to the present invention. It is a top view showing an example.

FIG. 10 is a perspective view showing a method for manufacturing a conventional liquid crystal display device. FIG. 11 is a plan view showing a method for manufacturing a conventional liquid crystal display device. BEST MODE FOR CARRYING OUT THE INVENTION

FIGS. 1 to 7 show a first example of the best mode for carrying out the method of manufacturing a liquid crystal display device according to the present invention.

This first example shows a method of manufacturing an ultra-thin liquid crystal display device used for a mopile device from a pair of mother glass 1 and 2.

In the manufacturing method of the liquid crystal display device of this embodiment, a polishing device (not shown), a scribing cutter, and the like are used. The polishing apparatus is provided with upper and lower platens, in which a polishing agent is poured to polish the liquid crystal cell sandwiched therebetween, and a double-side polishing apparatus is preferable, but a single-side polishing apparatus can also be used.

The scribing cutter (not shown) is a diamond-shaped or carbide-tipped cutter that is rotatably formed to cut the glass. The scribing cutter is rotated while applying a load on the glass surface. It is possible to cut along the cutting line by tearing the glass surface to make a cutting line and hitting the periphery of the wound.

The product-sized liquid crystal display device 10 is manufactured by laminating a pair of mother and glass together, making it thinner and smaller using a polishing device and a scribing cutter, and sealing the liquid crystal into the gap between the pair of glasses. It is. One is called the segment substrate 71 (1, 61 in the manufacturing process), and the other is called the common substrate 102 (2, 62, 72 in the manufacturing process). Various processes for controlling various displays are performed. The type of glass substrate used for this liquid crystal display device includes a super twisted nematic (STN) substrate and a thin film transistor (TFT) substrate. A method for manufacturing the liquid crystal display device having the above configuration will be described below.

First, a pair of mother glass 1 and 2 put into the production line are processed in a substrate processing step 21 as a pretreatment for forming one as a segment substrate 1 and the other as a common substrate 2 and displaying the liquid crystal. The formation of electrodes, the formation of alignment films, and processing are performed on the glass surface (matching surface). The size of these mother glasses 1 and 2 can be generally used in a small size of about 20 O mm X 200 mm in length and width and about 40 O mm X 500 mm in a large size. However, it is preferable that the size of the mother glass 1 and 2 be reduced without taking the product size into consideration.

Next, in the bonding step 22, first, as shown in FIG. 2, for the purpose of bonding glass, enclosing liquid crystal, and preventing intrusion of dust from the outside, band-shaped seals 11, 12 are formed. Coated and formed. The seal 11 is an outer peripheral seal 11 for a medium-sized cell, and is preferably formed in a rectangular shape so as to divide the mother glass 1 and 2 into a plurality of pieces. It is formed by dividing into two parts. More preferably, the number of divisions is 4 to 9, and this embodiment shows an example of division into four.

It should be noted that the number of divisions of the mother glass 1 and 2 is preferably at least 4 or more because 2 divisions are not meaningful as a medium-sized cell. Since it becomes higher, it is appropriate to use 9 or less.

In addition, at least one opening 111 is provided in each of the outer seals 11 for the medium-sized cells, and serves as a communication port for discharging air when the pair of mother glasses 1 and 2 are stacked. I have.

The seal 12 is a small-size cell seal 12 corresponding to the product size 13 surrounded by a dotted line, and is preferably formed in a square shape so as to divide the medium-size cell 6 into a plurality. The embodiment shows an example of dividing into four. The liquid crystal is sealed inside the seal 12. At least a part of the seal 12 is provided with an opening 121 for discharging air. As a material for such a seal, Xy-based resins are suitable. In the plan views of FIG. 2 and the like, since the seal 12 is similarly formed by printing on the glass substrate, the case is omitted by black dots.

Next, the segment substrate 1 and the common substrate 2 are bonded and fired at an appropriate temperature to form a large-sized cell 4. The thickness t 0 of the large-sized cell 4 is almost equal to the sum of the thicknesses of a pair of mother glass (because the thickness of the liquid crystal layer is about 5 m, which is very thin).

Subsequently, in the cutting step 23 for the medium-sized cells, scribing is performed to scratch both sides of the large-sized cells 4 (as indicated by the cutting lines 53 and 54). The scribed large-sized cell 5 is divided into a plurality of medium-sized cells 6 by means of a scribe break that is broken by being hit near the cutting lines 53 and 54 (in this embodiment, four cells).

In the next thinning step 24, the opening 1 11 that opens to face the cutting lines 53 and 54 is temporarily sealed, and at least one surface of the medium-sized cell 6 is polished. The thickness of the medium-sized cell 6 is reduced at one time from t 0 to t 2, which is the thickness of the product. For example, the thickness is reduced from the initial thickness t 0 = 1.4 mm (one side 7 mm) of the medium size cell 6 to the thickness t 2 = 0.4 mm (one side 0.2 mm) after polishing. You. Then, the abrasive and the like are washed and dropped. In the thinning step 24, the medium-sized cells 6 are exposed to abrasives, water, etc., but the openings 11 1 between the medium-sized segment substrate 61 and the medium-sized common substrate 62 are temporarily sealed. No foreign matter enters the cell because it is stopped.

Next, in the cutting step 25 for small-sized cells, cutting is performed along the cutting lines 63 and 64 in the same manner as in the cutting step 23 for medium-sized cells described above. In this embodiment, the small size cell 7 of the product size is formed by dividing into four, but the invention is not limited to four divisions, and the cell can be divided into an appropriate number according to the dimensions of the product size. . For example, about 4 to 9 divisions are preferable. At this time, the foreign matter that has entered the outer region 11a of the seal 11 of the medium-sized cell 6 in the thinning process 24 is cut by the cutting lines 63 and 64. It is not thrown away and does not stain terminal section 18 formed inside. Also, cracks that may occur in the outer region 11a of the seal 11 due to polishing in the thinning step 24 are discarded by cutting, so that the cause of defective products can be eliminated.

Then, the cut small-sized cell 7 is subjected to a single-side cutting step 26 of the terminal portion, and a part of the small-sized common substrate 7 2 is cut into a cutting line 7 3 so that the terminal can be formed on the small-sized segment substrate 7 1. It is preferable to form a small-sized cell 10 having a shape having a step in which one side of the small-sized common substrate 72 has been reduced by being cut at the same time.

Next, in the chamfering step 27 of the cut portion, chamfering of the corners of the divided surface is performed. Normally, when a break is made by scribing, the scribed surface 14 has many cracks running along the cutting lines 63, 64, as well as many in the direction different from the direction of the cutting lines 63, 64 due to various variations. Small cracks 15 (microcracks) often occur. In general, the cut corners are sharp and dangerous, so chamfering is performed, but this is to remove the sharp corners only, and does not consider the presence of microcracks. If the glass has an appropriate thickness, microcracks are not a serious problem, but the thinner the glass, the greater the effect. Here, as shown in FIG. 6, the chamfering process is performed so as to completely remove the microcracks 15 at the corners of the divided surface generated by scribing (as indicated by the chamfered line 16).

Then, after chamfering the corners of the divided surface, in a liquid crystal injection step 28, liquid crystal is injected from the opening 121, the opening 122 is sealed, and a polarizing plate is attached in a polarizing plate attaching step 29, The liquid crystal cell is completed through the inspection step 30.

According to this embodiment, the liquid crystal display device in which the large-sized cell 4 is divided into the medium-sized cells 6 including the plurality of small-sized cells 7, thinned in this state, and then divided into the small-sized cells 7. Because of this manufacturing method, it is easy to grind and thin a medium-sized cell smaller in size than the large-sized cell 4, and the thinning process can be performed only once. In addition, foreign matter is generated during the thinning process Is discarded. Therefore, the polishing process for thinning can be performed efficiently, and the terminal portion 18 formed inside does not become dirty, and a crack that may occur in the outer region 11 a of the seal 11 can be obtained. Can also be discarded, eliminating the cause of defective products.

Also, a plurality of outer seals 11 for medium-sized cells are formed in the large-sized cells 4, and the openings 11 1 are provided on the adjacent side of the outer seal 11 for medium-sized cells. When cut into the size cells 6, a seal is formed in a state where polishing and polishing are possible, and the openings 11 1 face the cut surface. Therefore, it is possible to proceed to the thinning process simply by first forming seals 11 on the mother glass 1 and 2 and cutting them into the medium-sized cells 6 along the cutting lines 53 and 54, facilitating the manufacturing process. become.

In addition, since micro cracks generated by scribing are completely removed, there is no starting point of breakage even if it is thinned, making it less likely to be damaged by shock input such as dropping mobile devices . FIGS. 8 and 9 show a second example of the best mode for carrying out the present invention. Here, the same components as those in the first example of the best mode are denoted by the same reference numerals.

The method of manufacturing a liquid crystal display device according to the present embodiment is different from the first example in that the cell thinning process is changed.

Here, a large-sized cell 4 on which the segment substrate 1 and the common substrate 2 are bonded is thinned to a predetermined thickness, and then divided into medium-sized cells 6. That is, a step of thinning the large-sized cell 4 having a thickness t0 to a thickness t1 is added. Therefore, before bonding the segment substrate 1 and the common substrate 2, close the outside of the large-sized cell 4 so that the abrasive or water does not enter the area 17 between the outer periphery seals 11 for the medium-sized cell 11. Is provided with a partial seal 30 for connecting the outer seal 11 for medium size cells. However, several places where partial seal 30 is applied (here 4 places ) At least one of them shall be an air vent opening 31. As a result, the segment substrate 1 and the common substrate 2 can be bonded to each other, and the opening 31 is sealed to perform a thinning process (polishing process).

Therefore, by providing such a partial seal 30 or the opening 31, it is not necessary to form a large seal that covers the entire large-sized cell 4, and the amount of the sealing material used can be minimized.

Also, when the large-sized cell 4 is divided into the medium-sized cell 6 and the medium-sized cell 6 (6 b) is divided into the small-sized cell 7, the outer region 1 la and the partial seal 30 of the seal 11 1, the opening Since 31 is cut off, no defective products are generated due to dirt or cracks in the terminal portion as in the first example. According to this embodiment, in addition to the same operation and effect as the first example of the embodiment of the method of manufacturing the liquid crystal display device, the large-sized cell 4 is thinned to an intermediate thickness. Since it is divided into medium-sized cells 6, the machining allowance for thinning in the medium-sized cells 6 is reduced, and processing is facilitated. In the thinning process of the large-sized cell 4, the partial seal 30 that connects the outer peripheral seal 11 for the medium-sized cell is provided, so there is no need to form a large seal that covers the entire large-sized cell 4. The amount of sealing material used can be minimized.

Note that, in the first and second examples of the above embodiment, cutting was performed using a scribing cutter, but it is also possible to perform cutting using a laser. In this case, since micro-cracks hardly occur, ordinary chamfering for removing sharp corners may be used.

Further, in the first and second examples of the above-described embodiment, the seal printing is performed on the segment substrate. However, the seal printing can be performed on the common substrate. Industrial applicability

As described above, according to the method of manufacturing a liquid crystal display device of the present invention, a large-sized cell stuck to the size of a mother glass is divided into a medium-sized cell including a plurality of small-sized cells, and in this state, the plate is thinned. After processing small size cell 7 Since the cell is divided into two, it is easy to grind a medium-sized cell smaller in size than a large-sized cell to make it thinner, and the thinning process can be performed only once. Further, the outer peripheral portion containing the foreign matter in the thinning process is discarded. Therefore, the polishing process for thinning can be performed efficiently, and the terminal portion formed on the inner side is not contaminated, and cracks that may occur in the outer region of the seal are discarded. The cause of defective products can be eliminated. As a result, a thin liquid crystal display device for a mopile device can be produced at a low cost, and the thinner liquid crystal display device enables a thinner mobile device.

In addition, since microcracks generated by scribing are completely removed, there is no starting point for damage even if the sheet is thinned, and a mopile device that is hard to be damaged by a shock input such as dropping can be obtained.

Claims

The scope of the claims

1. A large-sized cell that has been subjected to pre-processing and bonding for liquid crystal display on a pair of mother glass is divided into a plurality of medium-sized cells, and the medium-sized cells are thinned and the product thickness is reduced. After that, a method of manufacturing a liquid crystal display device, which is divided into small cells of a product size.

2. The method for manufacturing a liquid crystal display device according to claim 1, wherein the large-sized cell is provided with a medium-sized cell outer peripheral seal so as to surround a portion where the medium-sized cell is formed. A method for manufacturing a liquid crystal display device, characterized in that at least one opening for air release to be formed is formed on a side adjacent to a medium-sized cell.

3. The method for manufacturing a liquid crystal display device according to claim 1 or 2, wherein the large-sized cells are thinned before dividing the large-sized cells into medium-sized cells. .

4. The method for manufacturing a liquid crystal display device according to claim 3, wherein a partial seal for sealing between adjacent outer peripheral seals for medium size cells is provided, and at least one of the seals is provided with an air vent opening. A method for manufacturing a liquid crystal display device, comprising:

5. In the method for manufacturing a liquid crystal display device according to any one of claims 1 to 4, after the scribing is performed to divide the cell into small-sized cells, microcracks at the corners of the divided surface generated by the scribing are removed. A method for manufacturing a liquid crystal display device, comprising:

6. The method for manufacturing a liquid crystal display device according to any one of claims 1 to 5, wherein the medium-sized cell divides a large-sized cell into 4 to 12 cells, more preferably 4 to 9 cells. Manufacturing method of a liquid crystal display device.