JPWO2003100509A1 - Manufacturing method of liquid crystal display device - Google Patents

Abstract

The present invention relates to a manufacturing method that enables low-cost production of a liquid crystal display device having a glass substrate, particularly a liquid crystal display device for a thin mobile device such as a mobile phone. The method for producing a liquid crystal display device according to the present invention comprises dividing a large size cell (4), which has been subjected to a pretreatment for liquid crystal display on a pair of mother glasses (1) and (2), into a plurality of sizes, and dividing the medium size into a plurality of sizes. A cell (6) is formed, and the medium size cell (6) is thinned to obtain a product thickness, and then divided into small size cells (7) and (10) of the product size. By this manufacturing method, it is possible to efficiently perform the polishing process for thinning the plate and eliminate the cause of defective products.

Description

TECHNICAL FIELD 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 and portable devices such as mobile phones and audio devices.
Background Art In recent years, there has been an increasing need for small, thin, and light weight mobile devices and portable devices using liquid crystals. Recently, a folding mobile phone has a sub-display on its outer surface to provide time and electronic information. The number of people who can immediately see whether or not an email has been received is increasing. Such sub-displays are required to have higher functions, but the increase in the thickness of the sub-displays affects the overall thickness of the device, and there is a demand for thinner displays (liquid crystal display devices). It is high.
Conventionally, as a manufacturing method of a liquid crystal display device used for a mobile device, for example, there is a method as shown in FIG. In this method, a pair of glass substrates (mother glass) having a size such that a large number of product-sized liquid crystal cells can be obtained is prepared, and as a pretreatment for liquid crystal display, formation of an electrode (not shown), formation of an alignment film, The segment substrate 91 and the common substrate 92 are formed by performing processing or the like.
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 the size that will be cut later and become a liquid crystal cell of the product size. Further, an outer peripheral seal 93 is printed on the outer peripheral area of the segment substrate 91. Then, the segment substrate 91 and the common substrate 92 are bonded together to form the large size cell 96, and the seal 82 and the outer peripheral seal 93 are cured by baking at an appropriate temperature. Note that openings 83 and 94 are provided in the seal 82 and the outer peripheral seal 93 so that when the segment substrate 91 and the common substrate 92 are bonded together, air is released so that the seal is not broken. Further, after bonding, the opening 94 of the outer peripheral seal 93 is temporarily sealed with an epoxy resin or the like. This prevents foreign matters such as water and abrasives from entering the inside through a very narrow gap (usually about 5 μm) between the segment substrate 91 and the common substrate 92 in the next polishing step.
Next, at least one surface of the large-size cell 96 is polished by adding an abrasive with a polishing apparatus, and the plate thickness is reduced from t0 to t1, thereby forming a thin large-size cell 96a. In this polishing process, for example, the large cell 96 having a thickness t0 = 1.0 mm (0.5 mm on one side) is thinner than the large cell 96a with a thickness t1 = 0.6 mm (0.3 mm on one side). Polished to an extent. However, further thinning is difficult because the size of the mother glass tends to break.
Subsequently, the thinned large size cell 96 is cut into small size cells 97 which are product sizes. At that time, in the outer peripheral region, the outer peripheral seal 93 is discarded by cutting along a line 95 slightly inside the outer peripheral seal 93. In addition, foreign substances 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 small size cell 97 is injected with liquid crystal 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 size cell 97 is thinned to a plate thickness t2 and finished into a liquid crystal cell 97a having a product thickness t2. In the thinning of the polishing step, for example, the thickness t1 = 0.6 mm (one side 0.3 mm) of the small size cell 97 is about t2 = 0.4 mm (one side 0.2 mm) in the liquid crystal cell 97a. Until polished.
In this way, a product is formed through two polishing steps. In the second polishing step, foreign substances such as abrasive may enter the outer region 82a of the seal 82, and in this region, the terminal portion As a result, the terminal portion becomes dirty, and malfunctions are likely to occur. Further, since there is no allowance for the outer region 82a of the seal 82, if a crack is caused by the polishing process, it becomes a defective product. That is, the product yield deteriorates and the production efficiency decreases. Therefore, there is a problem that such a conventional production method increases the production cost.
In addition, in order to reduce the cost, it may be used without polishing using a relatively thin glass, but in the manufacturing process of the cell, it tends to cause deformation and breakage of the glass during transportation, washing, processing, Ultra-thin glass cannot be used in the manufacturing process. That is, there is a problem in that an ultra-thin display cannot be produced and cannot be made into an ultra-thin product.
The present invention has been made in consideration of such problems, and by improving the polishing process for thinning the plate, it is possible to eliminate the generation of defective products and increase the production efficiency to obtain a low-cost liquid crystal display device. An object of the present invention is to provide a method for manufacturing a liquid crystal display device.
DISCLOSURE OF THE INVENTION According to the method for manufacturing a liquid crystal display device according to claim 1 of the present invention, after a large size cell is divided into medium size cells including a plurality of small size cells, and after being thinned in this state, Divided into small cells. Thinning is easy because of the medium size cell, and the thinning process is performed only once. Moreover, the outer peripheral part containing the foreign material is discarded in the thinning process.
Furthermore, according to the method for manufacturing a liquid crystal display device according to claim 2 of the present invention, a plurality of medium-size cell outer periphery seals are formed in the large-size cell, and the openings thereof are adjacent to the medium-size cell outer periphery seal. Provided on the side. Accordingly, when the medium size cell is cut, a seal is formed in a state where polishing can be performed, and the opening portion faces the cut surface.
According to the method for manufacturing a liquid crystal display device according to claim 3 of the present invention, the large-size cell is thinned to an intermediate thickness and divided into medium-size cells. As a result, the processing cost for the thin plate processing in the medium size cell is reduced, and the processing is facilitated.
According to the method for manufacturing a liquid crystal display device according to claim 4 of the present invention, the gap between adjacent outer peripheral seals for medium-sized cells is sealed with a partial seal, and at least one of them is an opening. Is done. Thereby, the space between the mother glasses is completely sealed, and polishing can be performed in the state of a large size cell.
Further, according to the method for manufacturing a liquid crystal display device according to claim 5 of the present invention, microcracks generated by scribing are completely removed, and even if it is thin, it is difficult to break against impact input or the like.
Further, according to the method for manufacturing a liquid crystal display device according to claim 6 of the present invention, the large-sized cell is divided into medium-sized cells of an appropriate size, and the next thinning process is facilitated.
Other objects and features of the present invention will become apparent from the following detailed description based on the accompanying drawings.
BEST MODE FOR CARRYING OUT THE INVENTION FIGS. 1 to 7 show a first example of the best mode for carrying out the method for manufacturing a liquid crystal display device of the present invention.
In this first example, a method of manufacturing an ultra-thin liquid crystal display device used for mobile devices from a pair of mother glasses 1 and 2 is shown.
In the manufacturing method of the liquid crystal display device of this embodiment, a polishing device, a scribing cutter, etc. (not shown) are used. As the polishing apparatus, a platen is provided on the upper and lower sides, a polishing agent is poured into the liquid crystal cell sandwiched therebetween, and a double-side polishing apparatus is desirable, but a single-side polishing apparatus can also be used.
A scribing cutter (not shown) is a diamond or carbide roller cutter that can be rotated to cut the glass, and rolls the scribing cutter onto the glass surface while applying a load on the glass surface. It is possible to cut along the cutting line by attaching a scratch to be a cutting line and hitting around the wound.
The liquid crystal display device 10 of a product size is manufactured by bonding a pair of mother glasses, making them thin and small using a polishing device or a scribing cutter, and enclosing the liquid crystal in a gap between the pair of glasses. . One is called the segment substrate 71 (1, 61 in the manufacturing process), and the other is the common substrate 102 (2, 62, 72 in the manufacturing process). Various treatments that make it possible.
Examples of the glass substrate used in the liquid crystal display device include an STN (Super Twisted Nematic) substrate and a TFT (Thin Film Transistor) substrate.
A method of manufacturing the liquid crystal display device having the above configuration will be described below.
As a pretreatment for forming a pair of mother glasses 1 and 2 introduced into the production line at first in the substrate processing step 21, one as a segment substrate 1 and the other as a common substrate 2 to display a liquid crystal. An electrode, an alignment film, and a treatment are performed on the mating surface. As for the size of the mother glasses 1 and 2, a small size of 200 mm × 200 mm in length and width can be generally used, and a size of about 400 mm × 500 mm is generally usable. However, there is no waste in consideration of the product size. Preferably, the size is 2.
Next, in the bonding step 22, as shown in FIG. 2, the seals 11 and 12 are first formed in a strip shape for the purpose of glass adhesion, liquid crystal encapsulation, and prevention of intrusion of dust from the outside. The This seal 11 is an outer periphery seal 11 for medium-sized cells, and is preferably formed in a quadrangular shape so as to divide the mother glasses 1 and 2 into a plurality of pieces, and is divided into four, six, nine, twelve, etc. As shown in FIG. More preferably, it is 4 to 9 divisions, and in this embodiment, an example of division into four is shown.
Note that the number of divisions of the mother glasses 1 and 2 is preferably at least 4 divisions because it is not meaningful to make medium-sized cells in 2 divisions, and if they are 12 divisions or more, the number of processing becomes too large and the cost increases. Therefore, 9 divisions or less are appropriate.
Further, at least one opening 111 is provided in each of the medium size cell outer periphery seals 11 and serves as a communication port for releasing air when the pair of mother glasses 1 and 2 are stacked.
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 quadrangular shape so as to divide the medium size cell 6 into a plurality. In the example shown in FIG. The liquid crystal is sealed inside the seal 12. An opening 121 for releasing air is provided in at least a part of the seal 12. As such a seal material, an epoxy resin or the like is suitable. In each plan view such as FIG. 2, the seal 12 is printed and formed on the glass substrate in the same manner, and this case is omitted by a black dot.
Next, the segment substrate 1 and the common substrate 2 are bonded together and fired at an appropriate temperature, whereby the large-sized cell 4 is made. The thickness t0 of the large size cell 4 is almost equal to the sum of the thicknesses of the pair of mother glasses (because the liquid crystal layer has a very thin thickness of about 5 μm).
Subsequently, in the cutting step 23 for medium-sized cells, scribing is performed to scratch both surfaces of the large-sized cell 4 (as shown by the cutting lines 53 and 54). The scribed large size cell 5 is divided into a plurality of medium size cells 6 (in this embodiment, four) by a scribe break that breaks when hit in the vicinity of the cutting lines 53 and 54.
In the next thinning step 24, the opening 111 that opens facing the cutting lines 53 and 54 is temporarily sealed, and at least one surface of the medium-sized cell 6 is polished. The plate thickness is reduced at a time from t0 to t2, which is the thickness of the product. For example, the thickness is reduced from the initial plate thickness t0 = 1.4 mm (one side 0.7 mm) of the medium-sized cell 6 to the plate thickness t2 after polishing = 0.4 mm (one side 0.2 mm). Then, the abrasive or the like is washed away. In the thinning step 24, the medium size cell 6 is exposed to an abrasive and water. However, since the opening 111 is temporarily sealed between the medium size segment substrate 61 and the medium size common substrate 62, the cell There is no intrusion of foreign matter inside.
Next, in the cutting step 25 for small cells, cutting is performed along the cutting lines 63 and 64 in the same manner as the cutting step 23 for medium size cells. In this embodiment, the small cell 7 having a product size is formed by dividing into four, but is not limited to four, and can be divided into an appropriate number depending on the size 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 size cell 6 in the thinning step 24 is discarded by cutting at the cutting lines 63 and 64, and the terminal portion 18 formed inside is not soiled. In addition, 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 size cell 7 is formed by cutting a part of the small size common substrate 72 along the cutting line 73 so that the terminal can be formed on the small size segment substrate 71 in the single side cutting step 26 of the terminal portion. It is desirable that the small-sized cell 10 has a shape having a step where one side of the small-sized common substrate 72 is reduced.
Next, in the chamfering step 27 of the cut portion, the chamfers of the divided surface corner portions are performed. Normally, when a break is made by scribing, in addition to the cracks that run along the cutting lines 63 and 64 on the scribe surface 14, many small cracks 15 ( Microcracks) often occur. In general, the cut corner is chamfered because it is in a sharp state and is dangerous, but it is only for removing the sharp corner and does not consider the presence of microcracks. If the glass has an appropriate thickness, microcracks are not a problem, but the effect becomes greater as the glass becomes thinner. Here, as shown in FIG. 6, the chamfering is performed so as to completely remove the microcracks 15 at the corners of the divided surface generated by scribing (as indicated by the chamfer line 16).
Then, after chamfering the divided corners, liquid crystal is injected from the opening 121 in the liquid crystal injection step 28, the opening 121 is sealed, the polarizing plate is attached in the polarizing plate attaching step 29, and the inspection step 30 is passed. A liquid crystal cell is completed.
According to this embodiment, the large-sized cell 4 is divided into medium-sized cells 6 including a plurality of small-sized cells 7, and after being thinned in this state, the liquid crystal display device is divided into small-sized cells 7. Therefore, it is easy to polish and thin a medium-sized cell having a smaller size than the large-sized cell 4, and the thinning process can be performed only once. Moreover, the outer peripheral part containing the foreign material is discarded in the thinning process. Therefore, the thinning process can be efficiently performed, the terminal portion 18 formed on the inner side is not soiled, and cracks that may occur in the outer region 11a of the seal 11 are also discarded. The cause of non-defective products can be eliminated.
In addition, a plurality of medium size cell outer periphery seals 11 are formed in the large size cell 4, and the opening 111 is provided on the adjacent side of the medium size cell outer periphery seal 11. When cut, a seal is formed in a state where polishing can be performed, and the opening 111 faces the cut surface. Therefore, by first forming the seals 11 and the like on the mother glasses 1 and 2 and then cutting the medium-sized cell 6 with the cutting lines 53 and 54, the thinning process can proceed, and the manufacturing process becomes easy.
In addition, since microcracks generated by scribing are completely removed, there is no starting point for damage even if the plate is thinned, and it is difficult to damage against impact input that drops mobile devices. .
8 to 9 show a second example of the best mode for carrying out the invention. Here, the same symbols are attached to the same components as those in the first example of the best mode.
The manufacturing method of the liquid crystal display device according to this embodiment is different from the first example in the cell thinning process.
Here, the large size 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 size cells 6. That is, a step of thinning the large size cell 4 having the thickness t0 to the thickness t1 is added. Therefore, before the segment substrate 1 and the common substrate 2 are bonded, the middle size cell 4 is placed in the vicinity of the outside of the large size cell 4 so that the abrasive and water do not enter the region 17 between the adjacent outer seals 11 for the medium size cell. A partial seal 30 for connecting the outer peripheral seal 11 for size cells is provided. However, at least one of the several places (here, four places) where the partial seal 30 is applied is set as an opening 31 for venting air. Thereby, the segment substrate 1 and the common substrate 2 can be bonded together, the opening 31 is sealed, and a thinning process (polishing process) is performed.
Therefore, by providing such a partial seal 30 or opening 31, it is not necessary to form a large seal that covers the entire large-sized cell 4, and the amount of sealant used can be minimized.
Further, when the large size cell 4 is divided into the medium size cell 6 and from the medium size cell 6 (6b) into the small size cell 7, the outer region 11a of the seal 11, the partial seal 30, and the opening 31 are cut off. Therefore, as in the first example, a defective product is not generated due to dirt or cracks in the terminal portion.
According to this embodiment, in addition to the same operation and effect as the first example of the embodiment of the manufacturing method of the liquid crystal display device, the large size cell 4 is thinned to an intermediate thickness. Since it is divided into the medium size cell 6, the processing cost for the thin plate processing in the medium size cell 6 is reduced, and the processing becomes easy.
Further, in the thinning process of the large size cell 4, since the partial seal 30 for connecting the outer periphery seal 11 for the medium size cell is provided, it is not necessary to form a large seal covering the entire large size cell 4, and the sealing material Can be minimized.
In the first example and the second example of the above embodiment, the scribing cutter is used for cutting, but it is also possible to cut with a laser. In this case, since microcracks are hardly generated, normal chamfering for removing sharp divided surface corners may be used.
Further, in the first example and the second example of the above embodiment, the seal printing is performed on the segment substrate. However, it can be similarly performed on the common substrate.
Industrial Applicability As described above, the manufacturing method of the liquid crystal display device of the present invention is divided into medium-sized cells in which a large-sized cell bonded in the size of mother glass includes a plurality of small-sized cells, After being thinned in this state, it is divided into small-sized cells 7, so that it becomes easy to polish and thin a medium-sized cell having a smaller size than a large-sized cell. Can only be done once. Moreover, the outer peripheral part containing the foreign material is discarded in the thinning process. Therefore, the thinning process can be efficiently performed, 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, so that defective products are generated. The cause can be removed. As a result, a thin liquid crystal display device for mobile devices can be produced at low cost, and the liquid crystal display device can be thinned, so that the mobile device can be thinned.
In addition, since microcracks generated by scribing are completely removed, there is no starting point for damage even if the plate is thinned, and a mobile device that is not easily damaged by an impact input such as dropping can be obtained.
[Brief description of the drawings]
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 for manufacturing a liquid crystal display device according to the present invention.
FIG. 4 is a plan view showing the process of the first example of the embodiment of the manufacturing method of the liquid crystal display device according to the present invention.
FIG. 5 is a partially enlarged view of part S of FIG.
FIG. 6 is a sectional view taken along line XX of FIG.
FIG. 7 is a sectional view showing a state immediately after cutting in FIG.
FIG. 8 is a perspective view illustrating each manufacturing process, showing a second example of the embodiment of the manufacturing method of the liquid crystal display device according to the present invention.
FIG. 9 is a plan view showing a second example of the embodiment of the manufacturing method of the liquid crystal display device according to the present invention.
FIG. 10 is a perspective view showing a conventional method for manufacturing a liquid crystal display device.
FIG. 11 is a plan view showing a method of manufacturing a conventional liquid crystal display device.

[0003]
If there is a crack due to the polishing process, it will be a defective product. That is, the product yield deteriorates and the production efficiency decreases. Therefore, there is a problem that such a conventional production method increases the production cost.
In addition, in order to reduce the cost, it may be used without polishing using a relatively thin glass, but in the manufacturing process of the cell, it tends to cause deformation and breakage of the glass during transportation, washing, processing, Ultra-thin glass cannot be used in the manufacturing process. That is, there is a problem in that an ultra-thin display cannot be produced and cannot be made into an ultra-thin product.
The present invention has been made in view of such problems, and by improving the polishing process for thinning the plate, it is possible to eliminate the generation of defective products and increase the production efficiency to obtain a low-cost liquid crystal display device. An object of the present invention is to provide a method for manufacturing a liquid crystal display device.
DISCLOSURE OF THE INVENTION According to the method for manufacturing a liquid crystal display device according to claim 1 of the present invention, after a large size cell is divided into medium size cells including a plurality of small size cells, and after being thinned in this state, Divided into small size cells and liquid crystal is injected. Thinning is easy because of the medium size cell, and the thinning process is performed only once. Moreover, the outer peripheral part containing the foreign material is discarded in the thinning process.
Further, a plurality of medium size cell outer periphery seals are formed in the large size cell, and the openings are provided on adjacent sides of the medium size cell outer periphery seal. Accordingly, when the medium size cell is cut, a seal is formed in a state where polishing can be performed, and the opening portion faces the cut surface.
According to the method for manufacturing a liquid crystal display device according to claim 3 of the present invention, the large-sized cell is thinned to an intermediate thickness and divided into medium-sized cells. As a result, the processing cost for the thin plate processing in the medium size cell is reduced, and the processing is facilitated.

Claims (6)

A large size cell that has been pre-processed and bonded to a pair of mother glasses is divided into a plurality of medium-sized cells, and the medium-sized cells are processed into a thin plate to obtain a product thickness. A manufacturing method of a liquid crystal display device divided into small cells of a product size. In the manufacturing method of the liquid crystal display device according to claim 1, the outer periphery seal for the medium size cell is applied to the large size cell so as to surround the portion where the medium size cell is formed, and the outer periphery seal for the medium size cell is formed. A method of manufacturing a liquid crystal display device, wherein at least one opening for air venting is formed on a side where adjacent medium-sized cells are adjacent. 3. The method of manufacturing a liquid crystal display device according to claim 1, wherein the large size cell is thinned before dividing the large size cell into the medium size cell. 4. The method of manufacturing a liquid crystal display device according to claim 3, wherein a partial seal for sealing between adjacent peripheral seals for medium-sized cells is applied, and at least one of them is an opening for venting. A method for manufacturing a liquid crystal display device. 5. The method for manufacturing a liquid crystal display device according to claim 1, wherein the chamfering is performed so as to remove microcracks at the corners of the divided surface generated by scribing after scribing and dividing into small size cells. A method for manufacturing a liquid crystal display device. 6. The method of manufacturing a liquid crystal display device according to any one of claims 1 to 5, wherein the medium-sized cell divides the large-sized cell into 4 to 12 divisions, more preferably 4 to 9 divisions. Device manufacturing method.

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