JP2006337572A - Method for manufacturing liquid crystal display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a liquid crystal display element by which a UV-curing resin used as a sealing material can be completely cured in a step of sealing a liquid crystal injection port even when a dose of UV rays is regulated, and the specific resistance of the liquid crystal is uniformized to reliably prevent generation of display irregularity in the liquid crystal. <P>SOLUTION: UV irradiation and a heating process for curing a UV-curing resin 8 are consecutively carried out in one sealing material curing device 21 with respect to the UV-curing resin 8 applied on a liquid crystal injection port 4 of a frame-like seal part 3 formed in a cell 5 which is conveyed along a conveyance path. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a liquid crystal display panel, and more particularly to a method for manufacturing a liquid crystal display panel including a step of pressure-sealing liquid crystal in a cell cut into a stick shape.

  A conventional basic manufacturing method of a liquid crystal display panel and its problems will be briefly described with reference to FIGS.

  First, an undercoat layer (not shown) made of, for example, silicon oxide is formed on the transparent substrates 1 and 2 for the liquid crystal display panel in order to improve alkali barrier properties, and a transparent electrode (not shown) made of ITO or the like is formed thereon. ) Is formed, and then patterned into a predetermined shape. Thereafter, in an alignment treatment step, an alignment film (not shown) is applied and baked, and a rubbing treatment is performed.

  Thereafter, a sealing material containing a spacer material (not shown) for maintaining a gap is applied to one transparent substrate 1 in a substrate bonding / panel cutting process to form a seal portion. This seal portion is a frame-like seal portion 3 (hereinafter referred to as a frame-like seal portion 3) that has a liquid crystal injection port 4 protruding outward and is an outline of a region where an individual liquid crystal display panel is formed. . A plurality of the frame-shaped seal portions 3 are formed on the transparent substrate 1 so as to be arranged vertically and horizontally, and can be divided into individual liquid crystal display panels in a subsequent process. An electric signal input lead terminal portion (not shown) is formed outside each frame-shaped seal portion 3.

  On the other hand, on the opposing transparent substrate 2, a transparent electrode (not shown) is formed by patterning in a predetermined shape, an alignment film (not shown) is applied, formed, and rubbed, and then an in-plane spacer (not shown) is provided. Scatter.

  Then, the transparent substrate 1 on which the frame-shaped seal portion 3 is formed and the transparent substrate 2 on which the in-plane spacers are scattered are accurately aligned so that alignment marks (not shown) formed on the transparent substrates 1 and 2 match. By overlapping and thermocompression bonding, a bonded substrate (hereinafter referred to as a mother cell) in which a plurality of individual liquid crystal display panels are arranged so as to be separated is obtained.

  Next, the mother cell is cut into a plurality of sticks in which the frame-shaped seal portions 3 are arranged in the horizontal direction and the liquid crystal injection ports 4 of the frame-shaped seal portions 3 are opened on the same side. To do.

  Subsequently, in the liquid crystal injection step and the sealing step, the liquid crystal injection port 4 is immersed in the liquid crystal 7 in a vacuum, and the liquid crystal is sealed in the frame shape by utilizing a differential pressure and a capillary phenomenon when returning to atmospheric pressure. Injection into a cavity 9 surrounded by part 3.

  After that, in a state where a sticking bonded substrate (hereinafter referred to as “stick cell 5”) and a partition member made of foamed polyethylene having a measured heat resistance of about 60 ° C. are alternately stacked using a pressing jig. The stick cell 5 is pressurized, and the in-plane gap of the liquid crystal display panel surrounded by the frame-shaped seal portion 3 is controlled using the in-plane spacer. Then, extra liquid crystal out of the liquid crystal injected into the cavity 9 is pushed out from the liquid crystal injection port 4, an ultraviolet (UV) curable resin 8 as a sealing material is applied to the liquid crystal injection port 4, and the ultraviolet ray is irradiated to irradiate the liquid crystal. The ultraviolet curable resin 8 is cured, and the liquid crystal injection port 4 is sealed.

  Each stick cell 5 is displayed as an individual liquid crystal display on a planned dividing line (indicated by a broken line in FIGS. 5 and 6) located in a region between the frame-shaped seal portions 3 in the arrangement direction of the frame-shaped seal portions 3. A desired liquid crystal display panel is obtained by dividing the panel.

JP 2001-209062 A

  By the way, when the liquid crystal injection port is sealed with the ultraviolet curable resin 8, a method of increasing the ultraviolet irradiation amount is generally used as a method for completely solidifying the ultraviolet photosensitive resin.

  However, the ultraviolet light used for curing the ultraviolet curable resin 8 decomposes a part of the composition of the liquid crystal 7 and generates ionic impurities. The ultraviolet curable resin 8 is useful as a sealing material in that it can be cured in a short time, but since it is an acrylic adhesive material, it originally contains a large amount of ionic impurities. Therefore, in the step of curing the ultraviolet curable resin 8 with ultraviolet rays, impurities accumulate in the vicinity of the injection port, and this impurity lowers the specific resistance of the liquid crystal 7 located in the liquid crystal injection port 4 portion. As a result, the liquid crystal The threshold voltage may change at the inlet 4 portion, and display unevenness may occur. In particular, the liquid crystal 7 that can be driven at a low voltage exhibits a sensitive reaction to the amount of ultraviolet irradiation. Therefore, at present, the upper limit of the UV irradiation amount is regulated to seal the liquid crystal injection port 4 of the liquid crystal display panel.

  However, if the upper limit of the ultraviolet irradiation amount is regulated in this way, the ultraviolet irradiation amount is insufficient, the reaction of the ultraviolet curable resin 8 becomes insufficient, the surface of the ultraviolet curable resin 8 becomes uncured, and the subsequent In the work process, the uncured ultraviolet curable resin 8 that touched the operator's finger or the like may reattach to the surfaces of the transparent substrates 1 and 2.

  Further, conventionally, in the manufacturing process of the liquid crystal display panel, after the liquid crystal injection port 4 is sealed with the ultraviolet curable resin 8 for the purpose of reorienting the liquid crystal 7, the stick cell 5 is sealed, the kind of the liquid crystal 7 sealed, and the like. Depending on the temperature, a heat treatment may be performed at a heating temperature arbitrarily set (for example, about 130 to 140 ° C. at which a certain liquid crystal 7 is in a melt state). It has been confirmed that the curable resin 8 is completely cured.

  Therefore, each stick cell 5 that has been irradiated with ultraviolet rays is taken out from the pressurizing jig 11 and refilled into a heat-resistant heating rack, and the apparatus for performing ultraviolet irradiation on the stick cell 5 together with the heating rack is provided. Attempts have been made to completely cure the ultraviolet curable resin 8 by supplying it to a separately prepared heating device and performing a heat treatment (oven treatment).

  However, even when the stick cell 5 having the uncured ultraviolet curable resin 8 is refilled with a heating rack, the problem of reattachment of the ultraviolet curable resin 8 as described above occurs, and further, the liquid crystal 7 is reattached. Oven processing for the purpose of orientation takes another time, such as adjusting the heating temperature of the heating device, processing time, and increasing the number of work steps.

  The present invention has been made to solve such a problem, and when an ultraviolet curable resin is used as a sealing material, the liquid crystal injection port is sealed even when the ultraviolet irradiation amount is regulated. Provided is a method of manufacturing a liquid crystal display element capable of completely curing the ultraviolet curable resin in the process, and making the specific resistance of the liquid crystal uniform to prevent the occurrence of uneven display of the liquid crystal. It is for the purpose.

  In order to achieve the above object, a method of manufacturing a liquid crystal display panel according to the first aspect of the present invention includes a method in which liquid crystal is injected into a cavity surrounded by two substrates and a frame-shaped seal portion, and pressurized to control a gap. In the method of manufacturing a liquid crystal display panel in which the liquid crystal injection port formed in the frame-shaped seal portion is sealed with an ultraviolet curable resin as a sealing material, the transport path is formed in the cell transported. In addition, the ultraviolet curable resin applied to the liquid crystal injection port of the frame-shaped seal portion is continuously subjected to ultraviolet irradiation and heat treatment for the purpose of curing the ultraviolet curable resin in one sealing material curing device. It is characterized by performing.

  According to the method for producing a liquid crystal display panel of the present invention, in one encapsulating material curing device, the ultraviolet ray irradiation with respect to the ultraviolet curable resin as the encapsulating material and the heating temperature that promotes the reaction of the ultraviolet curable resin By continuously performing the heat treatment, it is possible to completely prevent the worker from touching the UV curable resin in an uncured state and reattaching the UV curable resin to the liquid crystal display panel. it can.

  And since the upper limit of the ultraviolet irradiation amount can be regulated by performing the curing of the ultraviolet curable resin in two steps of ultraviolet irradiation and heat treatment, even when using a liquid crystal that reacts sensitively to ultraviolet rays. The occurrence of the problem of a decrease in the specific resistance of the liquid crystal can be suppressed.

  Further, the gap control of the cells is performed by pressurizing a plurality of cells and a plurality of partition members alternately stacked and arranged in a pressurizing jig for the purpose of curing the ultraviolet curable resin. The ultraviolet irradiation and heat treatment are supplied to the conveying path of the sealing material curing device in a state in which partitioning members and a plurality of cells are alternately stacked on the pressing jig, and the inside of the sealing material curing device It is also characterized in that it is carried out continuously.

  According to this method of manufacturing a liquid crystal display panel, the process from the pressurization process for the purpose of controlling the gap of the cell to the process of sealing the liquid crystal injection port can be performed in the same cell holding state, so that the work efficiency is improved. Can be improved.

  Further, the heat treatment is performed such that the surface temperature of the ultraviolet curable resin is 85 ° C. or higher.

  According to this method for manufacturing a liquid crystal display panel, the ultraviolet curable resin can be reliably cured, and an increase in work steps (addition of a load step) can be prevented.

  According to the method for manufacturing a liquid crystal display panel of the present invention, when an ultraviolet curable resin is used as a sealing material, even when the ultraviolet ray irradiation amount is regulated, the liquid crystal injection port is completely sealed in the sealing step. The ultraviolet curable resin can be cured, and the specific resistance of the liquid crystal can be made uniform to prevent the occurrence of uneven display of the liquid crystal.

  Hereinafter, a method for manufacturing the liquid crystal display panel of the present embodiment will be described with reference to FIGS.

  In the liquid crystal display panel manufacturing method of the present embodiment, as in the above-described conventional liquid crystal display panel manufacturing method, two substrates are bonded together by frame-shaped seal portions of a plurality of liquid crystal display panels. Forming a strip-shaped stick cell by opening each liquid crystal injection port of the cylindrical seal portion on the same line, and injecting liquid crystal from each liquid crystal injection port into each cavity surrounded by each frame-shaped seal portion A step of controlling the gap by pressurizing the stick cell, a step of sealing each of the liquid crystal inlets with a sealing material, and each frame-shaped seal in the arrangement direction of each frame-shaped seal portion It has the process of dividing | segmenting by the parting plan line located in the area | region between parts, and cutting out to an individual liquid crystal display panel. In the following, focusing on the step of applying a sealing material to each liquid crystal injection port, which is a characteristic part in the method of manufacturing a liquid crystal display panel of the present invention, and the step of controlling the gap by pressurizing the stick cell related thereto. explain. In addition, while omitting or simplifying the description of each member already described in the conventional liquid crystal display panel manufacturing method, the present embodiment will be described using the same reference numerals.

  In the manufacturing method of the liquid crystal display panel of this embodiment, two transparent substrates 1 and 2 are bonded together by the frame-shaped seal portions 3 of the plurality of liquid crystal display panels, and the liquid crystal injection ports 4 of the frame-shaped seal portions 3 are connected. A plurality of stick cells 5 having a strip shape opened on the same line are used.

  The stick cell 5 is composed of a plurality of cells. In each cell, the liquid crystal 7 is injected from each liquid crystal injection port 4 into each cavity 9 surrounded by the frame-shaped seal portion 3.

  In this embodiment, each stick cell 5 is pressed using the pressurizing jig 11 in a state where the stick cells 5 and the partition members 6 are alternately stacked, and each frame is made use of an in-plane spacer. The gap in the cavity 9 (in-plane) surrounded by the cylindrical seal portion 3 is uniformly controlled.

  FIG. 1 is a front view showing an embodiment of the pressing jig 11.

  The pressing jig 11 is placed by stacking stick cells 5 (in FIG. 1 and FIG. 2, which are divided into three liquid crystal display panels which are finally divided) serving as a liquid crystal display panel. The mounting plate 12 has two side plates 17 disposed on both sides of the mounting plate 12.

  Bolt struts 13 are formed at four corners of the mounting plate 12 so as to protrude perpendicularly to the mounting plate 12 described above. A screw groove 14 is formed on the peripheral surface of the bolt support 13, and a nut 15 can be screwed from its upper open end. The pressurizing jig 11 has a pressurizing upper plate 16 in which holes (not shown) through which the bolt columns 13 pass are formed at four corners. In addition, above the mounting plate 12, air that is capable of pressurizing the stick cell 5 and the like stacked on the mounting plate 12 in contact with the center of the upper surface of the pressing upper plate 16. A cylinder (not shown) is provided, and a pressure gauge (not shown) is provided in the air cylinder. Further, the pressurizing jig 11 has a partition member 6 interposed between the stick cells 5 to be stacked.

  In the present embodiment, as will be described later, since the pressurizing jig 11 is supplied and conveyed to the sealing material curing device 21 for heat treatment, each member constituting the pressurizing jig 11 has a heat resistant temperature. It shall be made of a high material. In particular, for the partition member 6, a partition member made of foamed polyethylene having a measured heat resistance temperature of 60 ° C. was used in the conventional method for manufacturing a liquid crystal display panel, but in this embodiment, the set temperature of the heat treatment is used. The partition member 6 made of foamed polyethylene having a heat resistant temperature of 110 ° C. or higher is used.

  When the pressurizing jig 11 having such a configuration is used, the pressurizing / sealing process is performed as follows.

  First, liquid crystal 7 is injected from each liquid crystal injection port 4 of each frame-shaped seal portion 3 of the stick cell 5. And the stick cell 5 and the partition member 6 are laminated | stacked alternately, and it positions on the mounting plate 2 mentioned above.

Then, the upper plate 16 for pressurization is placed on the uppermost portion with the bolt support 13 penetrating through the hole, and in this state, the air cylinder is driven to obtain a desired pressure (for example, 0.4 kgf / cm ^{2 to 3} kgf / cm ² ), and the gap in the cavity 9 (in-plane) surrounded by the frame-shaped seal portions 3 and 8 is uniformly controlled using the in-plane spacer. Then, nuts 15 are screwed onto the bolt struts 13 to fix them while maintaining the pressurized state, and left in that state for several minutes. And the sealing material which consists of ultraviolet curable resin 8 is apply | coated to the liquid-crystal injection hole 4 part of each stick cell 5, The said nut 15 is loosened while confirming the pressure which a pressure gauge shows, and pressure reduction is performed.

  Subsequently, in this embodiment, the stick cell 5 in a state where the partitioning members 6 are alternately stacked in the pressurizing jig 11 is transported and supplied into the sealing material curing device 21 together with the pressurizing jig 11. To do.

  FIG. 2 is a main part front view showing the state of the pressing jig 11 and the stick cell 5 when being supplied to the sealing material curing device 21, and FIG. 3 is the sealing material curing device 21. FIG.

  In the present embodiment, the sealing material curing device 21 includes two belt conveyors 22 as conveying means for conveying the pressing jig 11 that arranges the stick cells 5 in a stacked state. The two belt conveyors 22 are coated with the ultraviolet curable resin 8 of the stick cell 5 stacked and stored in the pressurizing jig 11 when the side plate 17 of the pressurizing jig 11 is placed. The liquid crystal injection holes 4 are arranged in parallel with each other so that they can be suspended while being exposed to the lower surface. Each of the belt conveyors 22 has an endless belt 24 that is wound around a pair of pulleys 25 and is stretched while being supported by a plurality of driven rollers 20. Then, the drive control device 23 having a motor is driven to rotate the pulley 25, thereby sealing the object to be conveyed, that is, the stick cell 5 stacked and accommodated in the pressing jig 11. The two belt conveyors 22 that can be conveyed from one end side to the other end side of the material curing device 21 are configured such that the drive conveyance is synchronized by the drive control device. In addition, about the structure of the conveyance means of the sealing material hardening apparatus 21, it does not restrict to this structure.

  An ultraviolet ray as a sealing material applied to the liquid crystal inlet 4 of each frame-shaped seal portion 3 formed in the stick cell 5 is disposed upstream of the transport path of the stick cell 5 in the sealing material curing device 21. An ultraviolet curing zone (ultraviolet curing furnace) 27 in which an ultraviolet irradiation device 26 capable of ultraviolet irradiation is disposed is formed on the curable resin 8. The ultraviolet irradiation device 26 includes one or a plurality of ultraviolet lamps 28, and in this embodiment, is disposed below the two belt conveyors 22 in the ultraviolet curing zone 27.

  Further, on the downstream side of the ultraviolet curing zone 27, a heating device for heat-treating the ultraviolet curable resin 8 which is irradiated with ultraviolet rays in the ultraviolet curing zone 27 and is completely cured or uncured at a necessary and sufficient temperature. A heating zone (heating furnace) 30 in which 29 is disposed is formed. The heating device 29 includes a heater 31 and a blower (not shown), and heats the ultraviolet curable resin 8 by blowing hot air at a set temperature onto the ultraviolet curable resin 8, thereby heating the ultraviolet curable resin 8. It is configured to promote the curing reaction. In the present embodiment, the curing reaction is arranged below the two belt conveyors 22 in the heating zone 30.

  The heating device 29 is not limited to the blower type heating device 29 used in the present embodiment, and for example, a heating processing device 29 using far infrared rays or a heating processing device 29 using a hot plate is used. Can do.

  And in this embodiment, with respect to the ultraviolet curable resin 8 applied to the liquid crystal injection port 4 of each frame-shaped seal part 3 of the stick cell 5 conveyed through the conveyance path of the sealing material curing device 21, the ultraviolet light is applied. The ultraviolet curable resin 8 is completely cured in the sealing material curing device 21 by performing ultraviolet irradiation in the irradiation zone 27 and subsequently performing heat treatment in the heating zone 30.

  Here, FIG. 4 shows the result of a curing confirmation test for verifying the heat treatment temperature in the heating device 29 of the present embodiment using the stick cell 5 in a state where the ultraviolet curable resin 8 is uncured as a sample. It is a table.

  In this verification test, ten samples are used for each set temperature verification test, and the degree of curing is confirmed by visual recognition and tactile sensation. The evaluation of the verification test is “◯” when the UV curable resin 8 is completely cured in 10 out of 10 stick cells 5, and the UV curable resin in 7 to 9 out of 10 stick cells 5. "△" when 8 is completely cured, "x" when 5 or 6 out of 10 stick cells 5 are completely cured of the UV curable resin 8, and less Cases were represented as “x”. The heating time was the same time (10 seconds) at each set temperature.

  As shown in the table of FIG. 4, when the surface of the ultraviolet curable resin 8 is heated to 55 ° C. and 65 ° C. as measured by a surface thermometer, the result of the verification test is more than half of the sticks. In the cell, it is still impossible to obtain a completely cured state of the ultraviolet curable resin 8, and even when heated to 75 ° C., it is possible to obtain a completely cured state of the ultraviolet curable resin 8 in about half of the stick cells. could not. When heated to 85 ° C. and 100 ° C., a sufficient cured state of the ultraviolet curable resin 8 could be obtained in most stick cells. Moreover, the sufficient cured state of the ultraviolet curable resin 8 could be obtained in all the samples by heat treatment at 110 ° C. or higher.

  Considering the result of this verification test, the heat treatment in the heating zone 30 in the present embodiment is performed so that the surface temperature of the ultraviolet curable resin 8 is 85 ° C. or higher. In particular, it is preferable that the temperature of heat processing shall be 110 degreeC.

  Then, after the ultraviolet curable resin 8 as the sealing material is completely cured and the sealing of the liquid crystal 7 is completed, the pressurization state of the pressurizing jig 11 is completely released.

  Finally, each of the stick cells 5 is to be divided in the region between the frame-shaped seal portions 3 and 8 in the arrangement direction of the frame-shaped seal portions 3 (see FIGS. 5 and 6, And display an individual liquid crystal display panel.

  According to the manufacturing method of the liquid crystal display panel of this embodiment, in one sealing material curing device 21, ultraviolet irradiation to the ultraviolet curable resin 8 as the sealing material and the ultraviolet curable resin 8 By continuously performing a heat treatment at a heating temperature that promotes the reaction, an operator touches the ultraviolet curable resin 8 in an uncured state, and the ultraviolet curable resin 8 is reattached to the liquid crystal display panel. Can be completely prevented.

  And since the upper limit of the amount of ultraviolet irradiation can be regulated by performing the two steps of ultraviolet irradiation and heat treatment to completely cure the ultraviolet curable resin 8, the liquid crystal 7 that reacts sensitively to ultraviolet rays is used. Even if it exists, generation | occurrence | production of the problem of the specific resistance fall of the liquid crystal 7 can be suppressed.

  In addition, the process from the pressurization process for the gap control of the stick cell 5 to the sealing of the liquid crystal inlet is performed in the same holding state of the stick cell 5, that is, in the state of being stacked on the pressurizing jig 11. Therefore, work efficiency can be improved.

  In addition, this invention is not limited to embodiment mentioned above, A various change is possible as needed.

The front view which shows the principal part structure of the pressure treatment used in embodiment of this invention, and the lamination | stacking state of the stick cell and partition member which are laminatedly accommodated in it The front view which shows the state when carrying out supply conveyance to the jig | tool for pressurization of FIG. 1, and the sealing material hardening device of a stick cell. The front view which shows the principal part structure of the sealing material hardening apparatus used in embodiment of this invention. Table showing results of curing confirmation test for verifying heat treatment temperature in heating apparatus of this embodiment The top view which shows the arrangement | sequence of each frame-shaped seal part formed in the stick cell in the manufacturing method of the conventional liquid crystal display panel The principal part expanded sectional view of the stick cell of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Transparent substrate 3 Frame-shaped seal part 4 Liquid crystal injection port 5 Stick cell 6 Partition member 7 Liquid crystal 8 UV curable resin (sealing material)
DESCRIPTION OF SYMBOLS 9 Cavity 11 Pressing jig | tool 12 Mounting board 13 Bolt support | pillar 14 Screw groove 15 Nut 16 Pressurizing upper plate 17 Side plate 20 Follower roller 21 Sealing material hardening device 22 Belt conveyor 23 Drive control device 24 Endless belt 25 Pulley 26 Ultraviolet irradiation Device 27 UV irradiation zone 28 UV lamp 29 Heating device 30 Heating zone 31 Heating heater

Claims (3)

Liquid crystal is injected into a cavity surrounded by two substrates and a frame-shaped seal portion, and a liquid crystal injection port formed in the frame-shaped seal portion is used as a sealing material for a cell whose pressure is controlled by being pressurized. In the manufacturing method of a liquid crystal display panel sealed with an ultraviolet curable resin,
The ultraviolet ray curable resin applied to the liquid crystal injection port formed in the cell conveyed through the conveyance path is subjected to ultraviolet irradiation and heat treatment for the purpose of curing the ultraviolet curable resin in one sealing material curing device. A process for producing a liquid crystal display panel, characterized in that it is carried out continuously. The gap control of the cells is performed by pressing in a state where a plurality of cells and a plurality of partition members are alternately stacked and arranged in a pressing jig,
The ultraviolet irradiation and heat treatment for the purpose of curing the ultraviolet curable resin is performed in a state where the partition member and the plurality of cells are alternately stacked on the pressurizing jig, and the conveying path of the sealing material curing device. The method for producing a liquid crystal display panel according to claim 1, wherein the liquid crystal display panel is continuously supplied in the sealing material curing device. The method for manufacturing a liquid crystal display panel according to claim 1, wherein the heat treatment is performed so that a surface temperature of the ultraviolet curable resin is 85 ° C. or higher.

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