JP2010249923A - Liquid crystal display device and method for manufacturing mother board of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the phenomenon that a liquid crystal cell sealant is peeled off when actually hardening an outer peripheral sealant and a liquid crystal display device, with respect to a mother board having many liquid crystal cells formed thereon. <P>SOLUTION: A mother TFT board and a mother counter board having a liquid crystal cell sealant and an outer peripheral sealant formed thereon are heated by far infrared rays from a heating plate 500 to temporarily harden the liquid crystal cell sealant and the outer peripheral sealant. A rubber heater in the heating plate 500 is divided into 8, and temperatures of heating plate portions corresponding to divided rubber heaters are measured by thermocouples 6A to 6H, and a temperature distribution of the heating plate 500 is controlled to uniformly temporarily harden the liquid crystal cell sealant and the outer peripheral sealant. whereby the sealant is prevented from being peeled off due to a pressure of gas in the mother board, which is generated in actual hardening. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a display device, and more particularly to a technique for manufacturing a small and thin liquid crystal display device with a high yield.

  In a liquid crystal display device, a counter substrate on which a color filter or the like is formed is installed at a location corresponding to a pixel electrode on a TFT substrate on which pixel electrodes and thin film transistors (TFTs) are formed in a matrix, and between the TFT substrate and the counter substrate. Liquid crystal is sandwiched. An image is formed by controlling the light transmittance of the liquid crystal molecules for each pixel.

  Since liquid crystal display devices are flat and lightweight, they are used in various fields. Small liquid crystal display devices are widely used in mobile phones and DSCs (Digital Still Cameras). In mobile phones, DSCs, and the like, there is a demand for reducing the overall thickness of the apparatus and reducing the weight. For this reason, there is a strong demand for reducing the overall thickness of the liquid crystal display device used.

  If the liquid crystal display device is manufactured individually, the manufacturing efficiency is poor. Therefore, a mother TFT substrate having a plurality of TFT substrates is manufactured, a mother counter substrate having a plurality of counter substrates is manufactured, and the mother TFT substrate and the mother counter substrate are bonded together to form a mother substrate. A method of cutting out individual liquid crystal cells from a substrate is used. The method of taking out a plurality of liquid crystal cells from a large glass substrate is carried out when the liquid crystal cell is large or small, but in the case of a small liquid crystal cell, the liquid crystal is taken out from the mother substrate per sheet. The number of cells becomes very large.

  The mother TFT substrate and the mother counter substrate are bonded together by a liquid crystal cell sealing material formed around the liquid crystal cell, and when a small liquid crystal cell is formed, an outer peripheral sealing material formed around the mother substrate. A thermosetting resin is generally used for this sealing material. It is not easy to heat a large glass substrate uniformly with a small energy in a short time. In particular, in forming a mother substrate of a liquid crystal display device, an apparatus that accurately maintains the distance between the mother TFT substrate and the mother counter substrate is also heated at the same time, so energy saving is difficult.

  In “Patent Document 1”, far infrared rays are used up to the temperature at which the sealing material is softened, and when the sealing material is cured by raising the temperature, the hot plate is brought into close contact with the substrate holding plate that supports the glass substrate. A technique for heating a sealing material for bonding a mother TFT substrate and a mother counter substrate is described. In the technique described in Patent Document 1, both the softening of the sealing material and the main curing of the sealing material are performed on the substrate bonding apparatus.

JP 2000-1119029 A

  FIG. 5 shows a case where a plurality of liquid crystal cells used in a liquid crystal display device having a screen size of 15.4 inches are formed on the mother substrate 1000. As shown in FIG. 5, in this example, eight 15.4 inch liquid crystal cells can be formed per one mother substrate. In FIG. 5, two liquid crystal cell sealing holes 50 for injecting liquid crystal are formed in the liquid crystal cell sealing material 30 of each liquid crystal cell.

  FIG. 6 shows a case where a 3-inch liquid crystal cell is arranged on a mother substrate of the same size. In FIG. 6, four sub-mother substrates are formed on the mother substrate 1000, and each of the sub-mother substrates includes 36 3-inch liquid crystal cells. Accordingly, 144 liquid crystal cells are formed on one mother substrate. The In this way, in the case of a small liquid crystal display panel, the number of liquid crystal cells formed per mother substrate is very large compared to the case of a large liquid crystal display panel.

  Further, there is a strong demand for thin liquid crystal display panels in small liquid crystal display devices. In order to meet this requirement, it is necessary to reduce the thickness of the TFT substrate and the counter substrate that constitute the liquid crystal display panel. In recent years, the thickness of the TFT substrate or the counter substrate has been reduced from 0.2 mm to about 0.15 mm in some cases. However, such a thin glass plate does not exist as a standard product. Further, such a thin glass substrate has a low strength and is difficult to process in the manufacturing process.

  Therefore, at the stage of forming the mother TFT substrate or the mother counter substrate, a standard glass substrate of 0.5 mm or 0.4 mm is used, and the mother TFT substrate and the mother counter substrate are bonded together to form the mother substrate. Polishing the outside of the substrate is performed. For polishing, mechanical polishing and chemical polishing may be used in combination, or only chemical polishing may be used. By polishing, the mother TFT substrate or the mother counter substrate is polished by about 0.15 mm to 0.25 mm.

  By the way, when the polishing liquid penetrates into the mother substrate, the individual liquid crystal cells are destroyed. Therefore, in the case of a small liquid crystal cell, it is necessary to prevent the polishing liquid from entering the mother substrate when the mother substrate is polished. For this reason, in the mother substrate on which a small liquid crystal display cell is formed, the outer peripheral sealing material 300 is formed in the periphery to prevent the polishing liquid crystal display device from entering the mother substrate. In FIG. 6, an exhaust portion 350 is formed in the outer peripheral sealing material 300, but this is sealed with a mother substrate sealing material before polishing.

  On the other hand, in a medium-sized or large-sized liquid crystal display panel, there is little demand for making the substrate thinner like a small-sized liquid crystal display panel. Therefore, in the case of a medium-sized or large-sized liquid crystal display panel, since polishing is not required, such a peripheral sealing material is not necessary for the mother substrate.

  In FIG. 6, a large number of liquid crystal cells are formed inside the outer peripheral sealing material 300 of the mother substrate. A liquid crystal cell sealing hole 30 for sealing liquid crystal is formed in the liquid crystal cell sealing material 30 that partitions the liquid crystal cell. The mother substrate 1000 is formed by bonding a mother counter substrate and a mother TFT substrate. The liquid crystal cell sealing material 30 and the peripheral sealing material 300 as shown in FIG. 6 are formed on the mother counter substrate. In order to prevent air from remaining inside when the mother counter substrate and the mother TFT substrate are bonded together, the outer peripheral sealing material 300 is formed with an exhaust portion 350 for extracting air.

  A large number of liquid crystal cell sealing materials 30 are formed in the liquid crystal cell formed inside the outer peripheral sealing material 300. Even if the air in each liquid crystal cell tries to go outside through the exhaust part 350 formed in the outer peripheral sealing material 300, if a large number of liquid crystal cell sealing materials 30 are formed inside the outer peripheral sealing material 300, this becomes a resistance, The air in the liquid crystal cell is not discharged outside in a short time. In FIG. 6, the mother substrate 1000 is divided into four sub-mother substrates, and the number of liquid crystal cell sealing materials 30 in the outer peripheral sealing material 300 is reduced so that air in each liquid crystal cell easily escapes outside. is not. In FIG. 6, the mother substrate 1000 is divided into four sub-mother substrates for the reasons described above. Hereinafter, in this specification. The terms “sub-mother board” and “mother board” are used interchangeably.

  Thus, the conditions for forming the mother substrate 1000 are very different between the medium-sized or large-sized liquid crystal cell and the small-sized liquid crystal cell. The mother TFT substrate and the mother counter substrate are bonded together by the outer peripheral sealing material 300 and the liquid crystal cell sealing material 30. These sealing materials are thermosetting adhesive materials.

  Therefore, in order to bond the mother TFT substrate and the mother counter substrate, it is necessary to heat these substrates. Although heating is performed using far-infrared rays, the mother substrate 1000 is large in size, and thus tends to generate a temperature distribution within the substrate. Specifically, the temperature around the mother substrate is lowered.

  When the mother TFT substrate and the mother counter substrate are bonded together to form the mother substrate 1000, the temporary curing of the sealing material that doubles the gap between the mother TFT substrate and the mother counter substrate and the main curing that completely cures the sealing material are performed. Process exists. If the sealing material is not sufficiently heated at the pre-curing stage, sufficient adhesive strength cannot be secured by the sealing material.

  In particular, in the mother substrate 1000 in which a large number of small liquid crystal cells are formed, air is likely to remain inside, and the residual air expands by heating, and generates a force to peel off the mother TFT substrate and the mother counter substrate. On the other hand, when temporary bonding is performed by heating the mother substrate 1000, since the temperature is low around the mother substrate, the bonding strength of the liquid crystal cell sealing material in the periphery is low. Therefore, the defect that the liquid crystal cell sealing material 30 peels around the mother substrate 1000 frequently occurs.

  An object of the present invention is to overcome the above-described problems, and to efficiently manufacture a small and thin liquid crystal display device without peeling of a sealing material with high yield.

  The present invention overcomes the above problems, and specific means are as follows.

(1) A method of manufacturing a liquid crystal display device having a liquid crystal cell comprising a TFT substrate in which pixels including pixel electrodes and TFTs are formed in a matrix and a counter substrate, and a plurality of TFT substrates on a mother TFT substrate Forming a plurality of liquid crystal cell sealing materials on the mother counter substrate, forming an outer periphery sealing material on the periphery, and superimposing the mother TFT substrate and the mother counter substrate to face the mother TFT substrate to the mother The substrate is heated to melt the liquid crystal cell sealing material and the outer peripheral sealing material, and the mother TFT substrate and the mother counter substrate are pressed by atmospheric pressure to define the distance between the mother TFT substrate and the mother counter substrate, and then The liquid crystal cell sealing material and the outer peripheral sealing material are further heated to be temporarily cured to form a mother substrate. For heating the mother counter substrate and the mother TFT substrate, far-infrared rays using a heating plate having four or more divided rubber heaters are used, and the heating plate has thermoelectric power corresponding to the divided rubber heaters. A pair is arranged and electric power is input to each of the divided rubber heaters according to the output of the thermocouple, and then the liquid crystal cell sealing material and the outer peripheral sealing material are fully cured by putting the mother substrate into a heating furnace. ,
Then, the outside of the mother substrate is polished, and then the liquid crystal cell is separated from the mother substrate.

  (2) The method for manufacturing a liquid crystal display device according to (1), wherein among the divided rubber heaters, one or more rubber heaters have different heating resistor densities inside.

  (3) The method for manufacturing a liquid crystal display device according to (1), wherein the rubber heater is divided into eight or more.

  (4) A mother TFT substrate and a mother counter substrate are bonded by a liquid crystal cell sealing material and a peripheral sealing material, and a mother substrate manufacturing method including a plurality of liquid crystal cells, wherein the mother TFT substrate and the mother counter substrate are overlapped, The mother TFT substrate and the mother counter substrate are melted by heating the mother TFT substrate and the mother counter substrate, and the mother TFT substrate and the mother counter substrate are pressed by an atmospheric pressure, whereby the mother TFT substrate and the mother counter substrate are pressed. The liquid crystal cell sealing material and the outer peripheral sealing material are further heated and temporarily cured, and the mother counter substrate and the mother TFT substrate are divided into four or more for heating. Using far infrared rays by a heating plate having a rubber heater, the heating plate has the split Thermocouples are arranged corresponding to the rubber heaters, electric power is input to each of the divided rubber heaters according to the output of the thermocouples, and then the mother substrate is put into a heating furnace to put the liquid crystal cell seal A method of manufacturing a mother substrate, comprising: main-curing the material and the outer peripheral sealing material.

  (5) The method for manufacturing a liquid crystal display device according to (4), wherein among the divided rubber heaters, one or more rubber heaters have different heating resistor densities inside.

  (6) The mother TFT substrate and the mother counter substrate are bonded by a liquid crystal cell sealing material and an outer peripheral sealing material, the opening of the outer peripheral sealing material is sealed by a sealing material, and a plurality of liquid crystal cells are placed inside the outer peripheral sealing material. A method of manufacturing a mother substrate, comprising: superposing the mother TFT substrate and the mother counter substrate; heating the mother TFT substrate and the mother counter substrate to melt the liquid crystal cell sealing material and the outer peripheral sealing material; A step of defining a distance between the mother TFT substrate and the mother counter substrate by pressing the TFT substrate and the mother counter substrate by atmospheric pressure, and then further heating and temporarily curing the liquid crystal cell sealing material and the outer peripheral sealing material. And heating the mother counter substrate and the mother TFT substrate into four or more rubber heats. A far-infrared ray from a heating plate having a thermocouple is used, and a thermocouple is disposed on the heating plate corresponding to the divided rubber heater, and electric power is input to each of the divided rubber heaters according to the output of the thermocouple. Then, the mother substrate is put into a heating furnace to fully cure the liquid crystal cell sealing material and the outer peripheral sealing material, and then the opening is sealed with a sealing material. Method.

  (7) The method for manufacturing a liquid crystal display device according to (6), wherein among the divided rubber heaters, one or more rubber heaters have different heating resistor densities inside.

  According to the present invention, when the mother TFT substrate and the mother counter substrate are temporarily bonded, the liquid crystal cell sealing material and the outer peripheral sealing material can be uniformly cured, so that the adhesive force of each liquid crystal cell can be made uniform. I can do it.

  Thus, after the liquid crystal cell seal material and the outer peripheral seal material are temporarily cured, when the mother substrate is put into a heating furnace and the liquid crystal cell seal material and the outer peripheral seal material are finally cured, the liquid crystal cell seal material or the It is possible to prevent the outer peripheral sealing material from peeling off.

It is sectional drawing of the gap extraction apparatus by this invention. It is a schematic diagram of the heating plate by this invention. It is a schematic diagram which shows the temperature setting by this invention. It is an example of the rubber heater by this invention. It is an example of the mother board | substrate which has a medium-sized liquid crystal cell. It is an example of the mother board | substrate which has a small liquid crystal cell which this invention makes object. It is process drawing of the manufacturing method of the liquid crystal display device by this invention. It is sectional drawing of the periphery of a mother board | substrate. It is a top view of a mother board. It is a top view of a liquid crystal cell.

  Hereinafter, the contents of the present invention will be described in detail by way of examples.

  1 to 4 are examples of a manufacturing apparatus that realizes a method of manufacturing a liquid crystal display device according to the present invention. Before describing FIGS. 1 to 4, a manufacturing process of a liquid crystal display device to which the present invention is applied will be described. FIG. 6 shows an example of a mother substrate 1000 for manufacturing a small-sized liquid crystal display device. In FIG. 6, the mother substrate 1000 is formed of four sub-mother substrates 1000. Each sub-mother substrate 1000 is formed with an outer peripheral sealing material 300, and the outer peripheral sealing material 300 is formed with an exhaust part 350 for escaping air inside. 36 small liquid crystal cells 1 are formed inside each outer peripheral sealing material 300. Hereinafter, the sub mother board 1000 is also referred to as a mother board 1000.

  Further, in this specification, a combination of the TFT substrate 10 and the counter substrate 20 is referred to as a liquid crystal cell 1, and a liquid crystal display panel is a liquid crystal display panel in which an upper polarizing plate and a lower polarizing plate are attached to the liquid crystal cell 1. A device in which a driving IC or the like is attached to a panel is called a liquid crystal display device.

  FIG. 7 is a process flow for forming a small liquid crystal cell 1 as an object of the present invention. In FIG. 7, a mother TFT substrate 100 on which a large number of TFT substrates 10 are formed and a mother counter substrate 200 on which a large number of counter substrates 20 are formed are formed separately (701, 702). Then, the separately formed mother TFT substrate 100 and the mother counter substrate 200 are bonded together, and the mother TFT substrate 100 and the mother counter substrate 200 are temporarily bonded by the outer peripheral sealing material 300 and the liquid crystal cell sealing material 30 formed on the mother counter substrate 200. (703).

  This temporary bonding process is as follows. First, the mother TFT substrate 100 and the mother counter substrate 200 are bonded together. Then, when it heats to about 110 degreeC, a sealing material will fuse | melt. As the sealing material, a thermosetting resin such as epoxy is used. The thermosetting resin has a property of melting first when heated and then curing when the temperature is further increased.

When the sealing material is melted by heating, the distance between the mother TFT substrate 100 and the mother counter substrate 200 is defined by the glass fiber 15 existing in the sealing material. This state is shown in FIG. In FIG. 8, a gate insulating film 11 and an interlayer insulating film 12 made of SiN or SiO ₂ are formed on the mother TFT substrate 100.

  In FIG. 8, the outer peripheral sealing material 300 is formed at the ends of the mother TFT substrate 100 and the mother counter substrate 200, and the liquid crystal cell sealing material 30 is formed inside the outer peripheral sealing material 300. The glass fiber 15 is included in both the outer peripheral sealing material 300 and the liquid crystal cell sealing material 30, and the distance between the mother counter substrate 200 and the mother TFT substrate 100 is defined by the glass fiber 15.

  In FIG. 8, the liquid crystal cell sealing material 30 is included in the liquid crystal cell 1. An organic passivation film 13 is formed on the interlayer insulating film 12 on the TFT substrate 10 side in the liquid crystal cell 1. A color filter 14 is formed on the counter substrate 20 side in the liquid crystal cell 1. On the color filter 14, columnar spacers 16 for defining the substrate interval in the display area 60 of the liquid crystal cell 1 are formed.

  Returning to FIG. 7, the sealing material is further raised to about 140 ° C., and the sealing material is temporarily cured. Thereafter, the mother substrate 1000 is put into a heating furnace and heated at about 150 ° C. for about 30 minutes to perform main curing (704). After the mother substrate 1000 is fully cured, the mother substrate 1000 is separated into four sub-mother substrates 1000. Separation is performed using a scribing method or the like. Hereinafter, the sub mother board 1000 is simply referred to as a mother board 1000.

  Thereafter, the exhaust portion 350 formed on the outer peripheral seal portion of the mother substrate 1000 is sealed with the mother substrate sealing material 400 (706). This is because the polishing liquid is prevented from entering the mother substrate 1000 from the exhaust part 350 when the mother substrate 1000 is polished. An ultraviolet curable resin is used as the sealing material. After the sealing material is applied, this part is irradiated with ultraviolet rays (UV) to cure the sealing material (707). This state is shown in FIG.

  Thereafter, the outer surface of the mother substrate 1000 is polished by mechanical polishing or chemical polishing, so that a predetermined mother substrate 1000 has a predetermined thickness (708). The liquid crystal cell 1 is separated from the mother substrate 1000 having a predetermined plate thickness by scribing or the like (709).

  In this state, since the liquid crystal cell 1 has not yet been filled with liquid crystal, the liquid crystal is sealed from the sealing hole 50 formed in the liquid crystal cell sealing material 30 (710). And the sealing hole 50 is sealed with the liquid crystal cell sealing material 40, and the liquid crystal cell 1 is completed. The liquid crystal cell sealing material 40 is also made of an ultraviolet curable resin.

  FIG. 10 is a plan view of the liquid crystal cell 1 formed as described above.

  In FIG. 10, the TFT substrate 10 and the counter substrate 20 are bonded by the liquid crystal cell sealing material 30. Since the TFT substrate 10 and the counter substrate 20 have already been polished, the thickness is 0.2 mm. A display area 60 is formed inside the liquid crystal cell sealing material 30. In the display region 60 of the TFT substrate 10, pixel electrodes and pixels including TFTs are formed in a matrix. In the display area 60 of the counter substrate 20, color filters are formed corresponding to the pixels of the TFT substrate 10.

  The TFT substrate 10 is formed larger than the counter substrate 20 substrate, and this portion serves as a terminal portion 25. A lead line such as a video signal line (not shown) and a scanning line (not shown) extends from the display area 60 to the terminal portion 25. An IC driver to be arranged later is connected to these lead lines. The terminal portion 25 is formed with terminals for inputting signals, power, and the like from an external circuit, and a flexible wiring board (not shown) is connected to the terminals, for example.

  FIG. 1 is a schematic cross-sectional view of a gap forming apparatus used in the process 703 in FIG. In FIG. 1A, a mother TFT substrate 100 and a mother counter substrate 200 are overlapped. The mother TFT substrate 100 and the mother counter substrate 200 are overlapped at different locations, and are carried between the two pressure sheets 600 of the gap take-out device. At this time, the sealing material formed on the mother counter substrate 200 is not yet melted.

  The pressure sheet 600 is fixed to a frame body 610 having a quadrangular outer shape in plan view. A packing 620 is formed at a portion where the pressure sheet 600 is fixed to the frame body 610, and the inside and the outside are insulated when the inside of the pressure sheet 600 is exhausted later. On the outside of the pressure sheet 600, a heating plate 500 is disposed with a predetermined distance from the pressure sheet 600.

  FIG. 1B shows a state where the inside of the upper and lower pressure sheets 600 is depressurized through an exhaust pipe (not shown). The exhaust pipe is formed in the frame 610. In FIG. 1B, by pulling a vacuum between the two pressure sheets 600, the mother substrate 1000 sandwiched between the two pressure sheets 600 is pushed from above and below by atmospheric pressure.

  The packing 620 is formed of a flexible material, and is deformed flexibly as the distance between the pressure sheets 600 is reduced by drawing a vacuum between the two pressure sheets 600. The configuration is such that the distance between the mother TFT substrates 100 is not affected.

  Even in such a state, a predetermined interval is maintained between the pressure sheet 600 and the heating plate 500. The heating plate 500 includes a rubber heater. By heating the heating plate 500, far infrared rays are generated from the heating plate 500, and the sealing material between the mother counter substrate 200 and the mother TFT substrate 100 is heated via the pressure sheet 600.

  As the sealing material, a thermosetting resin such as epoxy is used. When the sealing material is heated to about 110 ° C., the sealing material is softened. Then, since the mother counter substrate 200 and the mother TFT substrate 100 are pressed by the atmospheric pressure via the pressure sheet 600, the distance between the mother counter substrate 200 and the mother TFT substrate 100 is reduced. As shown in FIG. 8, the distance between the mother TFT substrate 100 and the mother counter substrate 200 is defined by the diameter of the glass fiber 15 included in the sealing material.

  Thereafter, when the power of the heating plate 500 is further increased and the temperature of the sealing material between the mother counter substrate 200 and the mother TFT substrate 100 is raised to about 140 ° C., the sealing material is temporarily cured, and the mother counter substrate 200 and the mother TFT substrate are 100 adheres. Thus, the time for raising the stacked mother counter substrate 200 and the mother TFT substrate 100 from room temperature to a temperature at which the sealing material is temporarily cured to 140 ° C. is about 30 minutes.

  The mother substrate 1000 with the sealing material temporarily cured in this way is put into a heating furnace set at 150 ° C. and heated for 30 minutes to completely cure the sealing material. During this heating, gas is generated from the TFT substrate 10 or the counter substrate 20. The generated gas is discharged from the exhaust part 350 of the outer peripheral sealing material 300. However, as shown in FIG. 6, if a large number of liquid crystal cells 1 are formed inside the outer peripheral sealing material 300, the generated gas is generated from the liquid crystal cell 1. The liquid gas is hindered by the liquid crystal cell sealing material 30 and is not easily released to the outside. The gas accumulated in the mother substrate 1000 without being released acts as a stress that peels off each liquid crystal cell sealing material 30.

  In the gap forming apparatus, the sealing material is temporarily cured by far infrared rays, and then the mother substrate 1000 is put into a heating furnace to perform the main curing. That is, the sealing material is heated by two processes. The reason why heating is performed in two processes is to improve throughput. That is, by setting the time for occupying the gap forming apparatus having a complicated apparatus configuration to about 30 minutes and performing the main curing in a heating furnace, a practical throughput can be secured without preparing a large number of gap forming apparatuses. This point is greatly different from the technique described in “Patent Document 1”.

  By the way, when the heating device 500 is used for heating with far infrared rays in the gap forming apparatus, a temperature difference tends to occur between the center and the periphery of the mother substrate 1000. Conventionally, for example, a temperature difference of about 35 ° C. has occurred between the center and the periphery. In this case, even if the temperature is 140 ° C. at the center of the mother substrate 1000, the temperature is about 105 ° C. around the mother substrate 1000. When the temperature is about 105 ° C., the sealing material is not sufficiently solidified.

  If the mother substrate 1000 is taken out from the gap drawing device in a state where the sealing material is not sufficiently solidified, the gap becomes unstable at this portion, and temporary bonding with the sealing material becomes insufficient. On the other hand, in the center of the screen, the sealing material has a temperature sufficient for temporary bonding. Therefore, in a state in which the mother substrate 1000 is taken out from the gap forming device, the adhesive force of the liquid crystal cell sealing material 30 formed in the peripheral portion of the mother substrate 1000 is lower than the adhesive force of the liquid crystal cell sealing material 30 formed in the central portion.

  In this state, when the mother substrate 1000 is put into a heating furnace and a gas is generated from the inside of the liquid crystal cell 1 to generate a stress that peels off the mother counter substrate 200 and the mother TFT substrate 100, the mother substrate 1000 is formed around the mother substrate 1000. The liquid crystal cell sealing material 30 is peeled off.

  The present invention can prevent the liquid crystal cell sealing material 30 from peeling off around the mother substrate 1000 and improve the manufacturing yield of the liquid crystal cell 1. FIG. 2 is a view showing a heating plate 500 used in the present invention. 2A is a plan view, and FIG. 2B is a cross-sectional view.

  In FIG.2 (b), the heating plate 500 becomes a structure which the metal plate 5 sandwiches a rubber heater. The thickness of both the rubber heater and the two metal plates 5 is 0.5 mm. In the present embodiment, Al is used for the metal plate 5, but Cu may also be used.

  As shown to Fig.2 (a), the rubber heater is divided | segmented into 8 of 4A-4H. And power is supplied to each rubber heater independently from the temperature regulators 7A-7H. Accordingly, the temperature can be accurately adjusted for each location of the metal plate 5 sandwiching the rubber heater.

  FIG. 3 is a plan view showing a state where the thermocouples 6A to 6H are installed at positions corresponding to the rubber heaters of the metal plate 5 in order to accurately control the temperature of each place of the heating plate 500. And temperature controller 7A-7H is installed corresponding to each thermocouple 6A-6H. The temperature controllers 7A to 7H supply current to the rubber heaters 4A to 4H. Currents are supplied from the temperature controllers 7A to 7H to the rubber heaters 4A to 4H via lead wires 650, respectively.

  By the way, in the gap drawing apparatus shown in FIG. 1, when power is uniformly supplied to the heating plate 500, the temperature is lowered around the heating plate 500. In the present invention, in order to take measures against this, larger power is supplied to the peripheral rubber heaters 4A, 4C, 4F, 4D and the like so that the mother substrate 1000 can be heated uniformly.

  Even if the divided rubber heater as shown in FIG. 2 or FIG. 3 is used, a predetermined temperature distribution may not be obtained. In such a case, the temperature of the mother substrate 1000 can be made more uniform by changing the density of the heating resistors in each divided rubber heater.

  FIG. 4 shows an example in which the rubber heater 4 in the heating plate 500 is divided, and the density of the heating resistor is changed in each divided rubber heater. In FIG. 4, the density of the heating resistor in the rubber heater is in three stages. In FIG. 4, the density ratio of the heating resistor at the center is the lowest and is 0.8. A region having an average heating resistor density ratio exists so as to surround the periphery. The average heating resistor density ratio is 1. Further, a region having a high heating resistor density ratio is formed in the corner portion. The average resistor density ratio in this region is 1.2.

  2 and 4 are compared, each of 4B and 4E shown in FIG. 2 is divided into two regions, and the density ratio of the heating resistor on the center side of the mother substrate 1000 is small. The rubber heaters 4G and 4H in FIG. 2 have an average heating resistor density ratio. In FIG. 2, the rubber heaters 4A, 4C, 4F, and 4D that exist at positions corresponding to the corner portions of the mother substrate 1000 are diagonally divided into two regions, and the heating resistor density ratio is higher on the corner side, 1.2, and the heating resistor density ratio is 1 on the more central side.

  With such a configuration, the temperature difference of the sealing material in the mother substrate 1000 in the gap extracting device can be set to 15 ° C. or less. According to such a configuration, the adhesive strength of the sealing material that can withstand the increase in the internal pressure of the mother substrate 1000 in the heating furnace can be obtained over the entire surface of the substrate.

  In addition, the division | segmentation number 8 of the rubber heater in this invention shown in FIG. 2 is an example. More or fewer divisions are possible. However, in the gap forming apparatus, in order to keep the temperature of the mother substrate 1000 sufficiently uniform, the number of divisions of the rubber heater is preferably 4 or more. If the number of divisions of the rubber heater is 8 or more, more accurate temperature control is possible.

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal cell, 5 ... Metal plate, 10 ... TFT substrate, 11 ... Gate insulating film, 12 ... Interlayer insulating film, 13 ... Organic passivation film, 14 ... Color filter, 15 ... Glass fiber, 16 ... Columnar spacer, 25 ... Terminal part, 20 ... Counter substrate, 30 ... Liquid crystal cell sealing material, 40 ... Liquid crystal cell sealing material, 50 ... Sealing hole, 60 ... Display area, 100 ... Mother TFT substrate, 200 ... Mother counter substrate, 300 ... Peripheral sealing material, 350 ... exhaust part, 400 ... mother substrate sealing material, 500 ... heating plate, 600 ... pressure sheet, 610 ... frame, 620 ... packing, 650 ... lead wire, 1000 ... mother substrate, 4, 4A to 4H ... rubber Heater, 6A-6H ... thermocouple, 7A-7H ... temperature controller.

Claims (7)

A method of manufacturing a liquid crystal display device having a liquid crystal cell composed of a TFT substrate in which pixels including pixel electrodes and TFTs are formed in a matrix and a counter substrate,
Forming a plurality of TFT substrates on the mother TFT substrate;
Forming a plurality of liquid crystal cell sealing materials on the mother counter substrate and forming a peripheral sealing material around the periphery;
The mother TFT substrate and the mother counter substrate are overlapped, the mother TFT substrate and the mother counter substrate are heated to melt the liquid crystal cell sealing material and the outer peripheral seal material, and the mother TFT substrate and the mother counter substrate are at atmospheric pressure. By defining the distance between the mother TFT substrate and the mother counter substrate,
Thereafter, the liquid crystal cell sealing material and the outer peripheral sealing material are further heated to temporarily cure to form a mother substrate,
For heating the mother counter substrate and the mother TFT substrate, using far infrared rays by a heating plate having a rubber heater divided into four or more,
Thermocouples are arranged on the heating plate corresponding to the divided rubber heaters, and electric power is input for each of the divided rubber heaters according to the output of the thermocouple,
Then, the liquid crystal cell sealing material and the outer peripheral sealing material are fully cured by putting the mother substrate into a heating furnace,
Then, polish the outside of the mother board,
Thereafter, a liquid crystal cell is separated from the mother substrate.   2. The method of manufacturing a liquid crystal display device according to claim 1, wherein among the divided rubber heaters, one or more rubber heaters have different heating resistor densities inside.   The method of manufacturing a liquid crystal display device according to claim 1, wherein the rubber heater is divided into eight or more. A mother TFT substrate and a mother counter substrate are bonded by a liquid crystal cell sealing material and an outer peripheral sealing material, and a manufacturing method of a mother substrate including a plurality of liquid crystal cells,
The mother TFT substrate and the mother counter substrate are overlapped, the mother TFT substrate and the mother counter substrate are heated to melt the liquid crystal cell sealing material and the outer peripheral seal material, and the mother TFT substrate and the mother counter substrate are at atmospheric pressure. The step of defining the distance between the mother TFT substrate and the mother counter substrate by pressing, and then further heating and temporarily curing the liquid crystal cell sealing material and the outer peripheral sealing material,
For heating the mother counter substrate and the mother TFT substrate, using far infrared rays by a heating plate having a rubber heater divided into four or more,
Thermocouples are arranged on the heating plate corresponding to the divided rubber heaters, and electric power is input for each of the divided rubber heaters according to the output of the thermocouple,
Thereafter, the mother substrate is put into a heating furnace, whereby the liquid crystal cell sealing material and the outer peripheral sealing material are fully cured.   5. The method of manufacturing a liquid crystal display device according to claim 4, wherein among the divided rubber heaters, at least one of the rubber heaters has a different density of the heating resistor therein. A mother TFT substrate and a mother counter substrate are bonded by a liquid crystal cell sealing material and an outer peripheral sealing material, an opening of the outer peripheral sealing material is sealed by a sealing material, and a mother substrate including a plurality of liquid crystal cells inside the outer peripheral sealing material A manufacturing method of
The mother TFT substrate and the mother counter substrate are overlapped, the mother TFT substrate and the mother counter substrate are heated to melt the liquid crystal cell sealing material and the outer peripheral seal material, and the mother TFT substrate and the mother counter substrate are at atmospheric pressure. The step of defining the distance between the mother TFT substrate and the mother counter substrate by pressing, and then further heating and temporarily curing the liquid crystal cell sealing material and the outer peripheral sealing material,
For heating the mother counter substrate and the mother TFT substrate, using far infrared rays by a heating plate having a rubber heater divided into four or more,
In the heating plate, thermocouples are arranged corresponding to the divided rubber heaters, and electric power is input for each of the divided rubber heaters according to the output of the thermocouple,
Then, the liquid crystal cell sealing material and the outer peripheral sealing material are fully cured by putting the mother substrate into a heating furnace,
Then, the manufacturing method of the mother board | substrate characterized by sealing the said opening part with a sealing material.   The method of manufacturing a liquid crystal display device according to claim 6, wherein among the divided rubber heaters, one or more rubber heaters have different heating resistor densities inside.

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