JP2007322693A - Method of manufacturing display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a liquid crystal display device for maintaining strength of a panel by preventing occurrence of micro-cracks. <P>SOLUTION: In a cell process out of a process of manufacturing the liquid crystal display device, a polishing process (step S7) is carried out after a scribing/breaking process (step S6). A scribing/breaking process is cutting the substrate by forming a cutting planned line (scribing line) by a diamond cutter or the like on a substrate to generate a single cell. A polishing process is polishing the single cell generated in the scribing/breaking process by a CMP method or the like. The polishing process is polishing an amount for removing a rib mark formed on the single cell, in the amount being a desired thickness as a thin liquid crystal panel. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a display device, and more particularly to a method for manufacturing a thin display device.

  A liquid crystal display device is widely used as a display device that displays various images such as characters and graphics. The manufacturing process of the liquid crystal display device is roughly divided into three processes: an array process, a cell process, and a module process. Here, a case where the liquid crystal display device is an active matrix liquid crystal display device will be described as an example.

  The array process is a process of forming pixel electrodes and TFTs (Thin Film Transistors) on one of the two glass substrates. Pixel electrodes and TFTs are formed in a matrix for the number of pixels.

  In the cell process, the surface treatment is performed on the array substrate generated in the array process and the color filter substrate facing the array substrate, and then the array substrate and the color filter substrate are bonded to each other. In this step, the liquid crystal is injected into (gap) and the polarizing plate is adhered after sealing. In recent years, particularly, liquid crystal display devices have been made thinner and lighter. For example, reducing the thickness of glass is performed. As a method for manufacturing a thin liquid crystal display device, it is common to use a thin glass that has been processed thin from the beginning, or to polish the glass thinly during the cell process. What was produced | generated by the cell process is generally called a liquid crystal display panel, a panel substrate, etc.

  The module process is a process of mounting electronic components such as a driving device and a backlight on the liquid crystal display panel generated in the cell process.

  FIG. 4 is an explanatory diagram for explaining a cell process in a manufacturing process of a general liquid crystal display device. In the following description, a case where a vacuum injection method is used as a liquid crystal filling method will be exemplified. As shown in FIG. 4, the cell process includes an alignment film formation process (step S101), a rubbing process (step S102), a sealant application process (step S103), a spacer spraying process (step S104), and an assembly sealing process (step). S105), a polishing step (step S106), a scribe / break step (step S107), a liquid crystal injection step (step S108), and a polarizing plate pasting step (step S109), which are performed in the order described above.

  In the alignment film forming step, a liquid alignment agent is applied to form an alignment film (step S101). In the rubbing process, grooves are formed on the alignment film in order to determine the alignment direction of the liquid crystal molecules (step S102).

  In the sealing agent application step, a sealing agent is formed for sealing so that the liquid crystal does not escape when the liquid crystal is injected (step S103). In the spacer spraying step, spacers for keeping the substrate gap constant are sprayed (step S104). In the assembly sealing process, the array substrate and the color filter substrate are bonded together (step S105).

  In the polishing process, the thickness of the substrate after the assembly and sealing process is reduced by, for example, a method using a polishing apparatus or a method using etching (step S106).

  In the scribing / breaking process, the outer peripheral portion and the like of the bonded substrates are cut (step S107). When manufacturing a small liquid crystal display device, the mother substrate (large glass substrate) capable of forming a plurality of panels is processed up to the polishing step, and the mother substrate is cut in the scribe / break step. It is common to divide and generate individual panels. In the scribing / breaking process, a cutting line (scribe line) is formed on one of the array and color filter substrates bonded together in the assembly and sealing process by cutting means such as a carbide wheel cutter or diamond wheel cutter. Then, a vertical crack (vertical crack) is provided, and by applying a mechanical force, the vertical crack penetrates to the back surface and is cut. The other substrate is cut in the same manner. Hereinafter, each panel generated by the scribe / break process is referred to as a single cell.

  In the liquid crystal injection step, for example, the single cell is filled with liquid crystal by a method such as a vacuum injection method or a dropping method, and the injection port is closed (step S108). Hereinafter, the panel produced | generated by the liquid-crystal injection process is described with a liquid crystal cell.

  In the polarizing plate attaching step, polarizing plates are attached to both surfaces of the liquid crystal cell (step S109). Since the optical axis of the polarizing plate is related to the rubbing direction, it is necessary to attach the polarizing plate in accordance with a predetermined position. The completed liquid crystal display panel is tested and inspected before moving to a module process.

  FIG. 5 is an explanatory view showing a panel formed in a manufacturing process of a general liquid crystal display device. The multi-panel 100 is a mother board generated in the assembly and sealing step (step S105). By polishing the multi-panel 100 in the polishing step (step S106), the multi-panel 101 having a small plate thickness is generated. The multi-panel 101 is cut in a scribe / break process (step S107), and a thin panel (single cell) 102 is generated.

  When a thin glass plate is used to manufacture a liquid crystal display panel by the above-described process, there is a problem that a transparent substrate is easily cracked. In particular, in a scribe / break process for forming a scribe line on a transparent substrate, not only vertical cracks but also minute cracks (horizontal cracks) in the horizontal direction and oblique directions are generated. Further, generally, a flawed region formed in a stripe shape near the blade cutter blade is called a rib mark. FIG. 6 is a cross-sectional view of a panel (single cell) when a scribe line is formed by a wheel cutter in a scribe / break process. As shown in FIG. 6, the rib mark 20 is formed on each surface of the array substrate 11 and the color filter substrate 12 included in the single cell 10. The depth of the rib mark 20 depends on the load that presses the wheel cutter. For example, when the thickness of the array substrate 11 and the color filter substrate 12 is 0.4 mm, the depth of the rib mark 20 is about 0.08 mm to 0 mm. The value is about 1 mm. The rib mark causes a micro crack, and the micro crack causes a decrease in the strength of the liquid crystal display panel.

  There has been proposed a scribing method and a scribing apparatus that can be a cutting process of only a scribing process without a break process in cutting glass (for example, see Patent Document 1). In Patent Document 1, in a scribing method in which a wheel cutter is pressed against the surface of a brittle material to perform relative movement to form a scribe line, the wheel is periodically vibrated in the vertical direction and the wheel moving direction with respect to the brittle material. Thus, it is described that the vertical crack is deepened and the horizontal crack is suppressed.

JP 2000-119031 (paragraphs 0015-0018)

  However, in the method described in Patent Document 1, as described in FIG. 4 of Patent Document 1, rib marks remain on the cut surface. The rib mark may be a starting point for cracking of the transparent substrate, and causes a decrease in the strength of the liquid crystal display panel.

  Therefore, an object of the present invention is to provide a method of manufacturing a liquid crystal display device that can maintain the strength of a panel even if scratches such as rib marks remain on the cut surface of the substrate.

  The display device manufacturing method according to the present invention is a thin display device manufacturing method in which a single cell is formed after a substrate on which two glass substrates are stacked is cut into a predetermined size to produce a single cell. The cell is polished to reduce the thickness.

  The amount of polishing the single cell is preferably an amount that achieves a desired thickness and that is equal to or greater than the depth of the scratch formed on the surface of the single cell when the substrate is cut. According to such a structure, the damage | wound formed at the time of the cutting | disconnection of a board | substrate can be removed in the grinding | polishing process for thickness reduction.

  According to the present invention, since the polishing process for generating the thin display panel is performed on the panel in which the rib mark is generated in the scribe / break process, the rib mark can be removed in the polishing process for reducing the thickness. it can. As a result, the cause of the occurrence of cracks can be eliminated, and the panel strength can be maintained.

  Hereinafter, an embodiment in which a display device is manufactured using two glass substrates will be described with reference to the drawings. FIG. 1 is an explanatory diagram for explaining a cell process in a manufacturing process of a liquid crystal display device according to the present invention. Here, the cell process in the manufacturing process of the liquid crystal display device will be described. Moreover, in the following description, the case where a vacuum injection method is used is illustrated as a liquid crystal filling method.

  As shown in FIG. 1, the cell process includes an alignment film forming process (step S1), a rubbing process (step S2), a sealant application process (step S3), a spacer spraying process (step S4), and an assembly sealing process (step). S5) is a process including a scribe / break process (step S6), a polishing process (step S7), a liquid crystal injection process (step S8), and a polarizing plate pasting process (step S9). In this invention, it implements in said order in a cell process.

  In the alignment film forming step, a liquid alignment agent is applied to the array substrate and the color filter substrate, dried and baked to form the alignment film (step S1). Next, in the rubbing process, grooves are formed on the alignment film in order to determine the alignment direction of the liquid crystal molecules (step S2).

  In the sealing agent application step, a sealing agent for sealing the liquid crystal so as not to escape when the liquid crystal is injected is formed on either the array substrate or the color filter substrate by screen printing or the like (step S3). In the spacer spraying step, spacers for keeping the gap between the array substrate and the color filter substrate constant are sprayed on either the array substrate or the color filter substrate (step S4). In the assembly and sealing step, the array substrate and the color filter substrate are bonded together, pressurized and sealed, and the sealant is cured by irradiating heat and ultraviolet rays (step S5).

  In the present invention, after the assembly and sealing process, a scribe / break process is performed (step S6). In the scribing / breaking step, the outer peripheral portion of the two bonded substrates is cut. When manufacturing a small liquid crystal display device, the mother substrate that can form a plurality of panels is processed up to the sealant application process, and the mother substrate is cut and divided into individual parts in the scribe / break process. It is common to produce a panel (single cell). In the scribing and breaking process, one of the array substrate and color filter substrate bonded together in the sealant application process is formed with a scribe line with a diamond cutter to create vertical cracks, and mechanical force is applied. To cut through the vertical crack to the back surface. The other substrate is cut in the same manner to produce a single cell.

  Next, a polishing process is performed (step S7). FIG. 2 is a cross-sectional view showing an example of a polishing apparatus. As shown in FIG. 2, the polishing apparatus includes a rotating shaft 1, a rotating surface plate 2, a polishing cloth 3, a carrier 4, a rotating shaft 5, and an abrasive supply nozzle 6.

  The rotating surface plate 2 has a flat surface and rotates around the rotating shaft 1. The polishing cloth 3 is a cloth affixed on the rotating surface plate 2.

  The carrier 4 is disposed on the upper surface of the rotary platen 2 and rotates around the rotation shaft 5. The carrier 4 holds one or a plurality of single cells 10 cut in the scribe / break process by, for example, a suction method.

  When polishing, the carrier 4 applies pressure from the back surface of the single cell 10 toward the rotating surface plate 2 via the carrier 4 holding the single cell 10, so that the surface to be polished of the single cell 10 is Press against the polishing cloth 3. Here, an abrasive containing abrasive grains is dripped onto the abrasive cloth 3 from the abrasive supply nozzle 6, and both the rotating surface plate 2 and the carrier 4 are rotated in opposite directions to give a relative speed. As a result, the polished surface of the single cell 10 is slid in contact with the polishing pad 3 and polished.

  The amount to be polished is an amount that provides a desired thickness for a thin liquid crystal display panel, and is an amount that can remove the rib mark 20 formed in the single cell 10. For example, each of the array substrate 11 and the color filter substrate 12 having a thickness of 0.4 mm and a rib mark 20 having a depth of 0.1 mm is finally formed as a liquid crystal display panel. When the thicknesses of 12 are 0.25 mm, the surfaces of the array substrate 11 and the color filter substrate 12 may be polished by 0.15 mm. The thickness of the array substrate 11 and the color filter substrate 12 is desirably a necessary and sufficient thickness by calculating back from the desired thickness of the finally generated liquid crystal display panel.

  In the above description, polishing by the CMP (Chemical Mechanical Polish) method is exemplified, but polishing may be performed by etching with hydrofluoric acid, for example. In the case of etching, a mask is applied to a portion that is not desired to be polished.

  When the polishing process is completed, the process proceeds to the liquid crystal injection process (step S8). Examples of the liquid crystal injection process include a vacuum injection method and a dropping method. In the vacuum injection method, a single cell is installed in an airtight device, the inside of the single cell is evacuated, the inlet of the single cell is immersed in a liquid crystal material, the inside of the airtight device is returned to atmospheric pressure, and capillary action is used. In this method, liquid crystal is filled in a single cell. After injecting the liquid crystal, a resin or the like is applied to the injection port of the cell, the adhesive at the injection port is cured by ultraviolet irradiation or the like to close the injection port, and a liquid crystal cell is generated.

  In the polarizing plate attaching step, the polarizing plate is attached to both surfaces of the liquid crystal cell (step S9). Since the optical axis of the polarizing plate is related to the rubbing direction, it is necessary to attach the polarizing plate in accordance with a predetermined position. The completed liquid crystal display panel is tested and inspected before moving to a module process.

  FIG. 3 is an explanatory view showing a panel formed in the manufacturing process of the liquid crystal display device according to the present invention. The multi-panel 100 is a mother substrate generated in the assembly and sealing step (step S5). The multi-panel 100 is cut in a scribe / break process (step S6), and the panel (single cell) 10 is generated. By thinning the panel (single cell) 10 in the polishing step (step S7), a thin panel 11 having a small plate thickness is generated. Since the panel (single cell) 10 is not polished, rib marks are formed on the surface of the substrate. By performing the polishing process (step S7) after the scribe / break process (step S6), the thin panel 11 from which the rib marks have been removed is generated.

  In the above embodiment, the individual panel (single cell) is polished after the scribe / break process (step S6) (step S7), and the process proceeds to the liquid crystal injection process (step S8). Although illustrated, the liquid crystal injection step (step S8) may be performed after the scribe / break step (step S6), and then the polishing step (step S7) may be performed on the liquid crystal cell.

  In the above embodiment, the case of using the vacuum injection method is exemplified as the liquid crystal filling method. However, for example, a drop injection method may be used. In the case of the dropping injection method, the assembly sealing process (step S5) is performed simultaneously with the liquid crystal injection process (step S8). Thereafter, similarly to the above-described embodiment, a scribe / break process (step S6) is performed, and a polishing process (step S7) is performed.

  As described above, according to the present embodiment, the polishing process for generating the thin liquid crystal display panel is performed on the panel in which the rib mark is generated in the scribe / break process. At the same time, the rib mark can be removed. Therefore, the cause of the occurrence of cracks can be removed, and the strength of the panel can be maintained. In addition, although this embodiment demonstrated and demonstrated the manufacturing method of the liquid crystal display device, it is applicable also to the manufacturing method of an organic EL display device and a plasma display device.

  The present invention can be applied to a method for manufacturing a display device, and can be particularly effectively applied to a method for manufacturing a thin display device.

Explanatory drawing for demonstrating the cell process among the manufacturing processes of the liquid crystal display device by this invention. Sectional drawing which shows the example of a grinding | polishing apparatus. Explanatory drawing which shows the panel formed in the manufacturing process of the liquid crystal display device by this invention. Explanatory drawing for demonstrating the cell process among the manufacturing processes of a general liquid crystal display device. Explanatory drawing which shows the panel formed in the manufacturing process of a general liquid crystal display device. Sectional drawing of the panel (single cell) at the time of forming a scribe line with a wheel cutter.

Explanation of symbols

S1 Alignment film forming process S2 Rubbing process S3 Sealant application process S4 Spacer spraying process S5 Assembly sealing process S6 Scribe / break process S7 Polishing process S8 Liquid crystal injection process S9 Polarizing plate pasting process

Claims (2)

In a method for manufacturing a thin display device,
After producing a single cell by cutting a substrate on which two glass substrates are laminated to a predetermined size,
A method of manufacturing a display device, comprising: polishing the generated single cell to reduce the thickness. The display device manufacturing method according to claim 1, wherein the amount of polishing the single cell is an amount that achieves a desired thickness, and is an amount that is equal to or greater than a depth of a scratch formed on the surface of the single cell when the substrate is cut. Method.

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