Production line of liquid crystal display device

The present invention relates to a production line of a liquid crystal display element, and more particularly to a production line of a liquid crystal display element by a liquid crystal dropping method.

Ultra-thin flat plate display elements with a display screen thickness of only a few centimeters, among which liquid crystal display elements have the advantages of low operating voltage, low power consumption, and can be used portablely, so laptop computers and monitors The fields of application are wide and diverse, including spacecraft and aircraft.

Such a liquid crystal display element is generally formed on a lower substrate on which a thin film transistor and a pixel electrode are formed so as to face the lower substrate, and on the light-shielding film, a color filter layer, and a common electrode. It is composed of an upper substrate on which the above-mentioned is formed and a liquid crystal layer formed between the two substrates, and an electric field is formed between the two substrates by the pixel electrode and the common electrode to drive the liquid crystal layer. The light transmission is adjusted through the driven liquid crystal layer so that the image is displayed.

In a liquid crystal display element having such a structure, as a method of forming a liquid crystal layer between the lower substrate and the upper substrate, a vacuum injection method using a capillary phenomenon and a pressure difference has been conventionally used, but vacuum injection The method has a problem that the productivity is inferior because a long liquid crystal injection time is required as the display screen becomes large in area.

Therefore, in order to solve such a problem, a new method called a liquid crystal dropping method has been proposed. Hereinafter, the liquid crystal display element by the conventional liquid crystal dropping method will be described with reference to the attached drawings.

1a to 1d are perspective views showing a manufacturing process of a liquid crystal display element by a liquid crystal dropping method as a related technique. First, as shown in FIG. 1a, the lower substrate 1 and the upper substrate 3 are prepared. Although not shown in the drawing, a plurality of gate wirings and data wirings that intersect horizontally and vertically to form a pixel region are formed on the lower substrate 1, and a thin film transistor is formed at the intersection of the gate wirings and the data wirings. Then, a pixel electrode connected to the thin film transistor is formed in the pixel region.

Further, a light-shielding film for blocking light leakage from the gate wiring, data wiring, and the thin film transistor formation region is formed on the upper substrate 3, and red, green, and blue color filter layers are formed on the light-shielding film. A common electrode is formed on it. Further, an alignment film for initial orientation of the liquid crystal is formed on the lower substrate 1 and the upper substrate 3.

Then, as shown in FIG. 1b, the sealant 7 is formed on the lower substrate 1, and the liquid crystal 5 is dropped to form the liquid crystal layer. Then, a spacer for maintaining the cell gap is sprayed on the upper substrate 3.

At this time, in the liquid crystal display element by the vacuum injection method described above, the bonding process of both substrates is performed before the liquid crystal is injected, but in the liquid crystal display element by the liquid crystal dropping method, both substrates 1 and 3 are dropped after the liquid crystal 5 is dropped. If a heat-curable sealant is used as the sealant 7, there arises a problem that the sealant 7 flows out while the sealant 7 is heated and the liquid crystal 5 is contaminated. Therefore, in the liquid crystal display element by the liquid crystal dropping method, a UV curable sealant is used as the sealant 7.

Then, as shown in FIG. 1c, the lower substrate 1 and the upper substrate 3 are joined together.

Then, as shown in FIG. 1d, the sealant 7 is cured by irradiating UV through the UV irradiation device 9. By curing the sealant 7 in this way, the lower substrate 1 and the upper substrate 3 are adhered to each other.

As described above, in the manufacture of the liquid crystal dropping type liquid crystal display element, the sealant 7 is cured by the UV irradiation step through the bonding step between the lower substrate 1 and the upper substrate 3 formed on the lower substrate 1. Therefore, if the sealant 7 formed on the lower substrate 1 is pre-cured before the execution of the bonding step, the adhesive strength between the lower substrate 1 and the upper substrate 3 is inferior.

Hereinafter, a production line of a liquid crystal display element by a liquid crystal dropping method as the related technology described above will be described.

First, the lower substrate on which the thin film transistor and the pixel electrode are formed is loaded into the first loading equipment, and then the sealant and the liquid crystal layer are formed on the lower substrate through the sealant coating equipment and the liquid crystal dropping equipment. Then, the light-shielding film, the color filter layer, and the upper substrate on which the common electrode is formed are loaded into the second loading equipment, and then the spacer is formed on the spacer spraying equipment.

Then, the lower substrate and the upper substrate move to the bonding equipment and are bonded, and then move to the UV irradiation equipment to cure the sealant by UV irradiation and bond them. At this time, equipment covers are installed on each process equipment and the line between the process equipment, but the upper part of such equipment covers is opened so that dust and the like generated during work can be scattered and discharged. The structure is made of a transparent material so that the worker can see the work piece with the naked eye. In addition, a lamp such as a fluorescent lamp is formed on the ceiling above the production line.

<p> However, since the upper part of the equipment cover is open and is made of a transparent material in this way, a part of the UV irradiated by the lamp covers the equipment cover and the upper surface on which the equipment cover is not installed. The substrate is irradiated through the substrate and the sealant is cured before reaching the bonding equipment, which eventually causes a problem that the adhesive strength of the bonded substrate is inferior.</p><p> Therefore, the present invention has been made to solve the above-mentioned problems, and the purpose of the present invention is to provide a liquid crystal display element configured so that the sealant does not cure before the bonding step. To provide a production line.</p>

<p> In order to achieve the above object, in the present invention, a production line shielding cover made of a UV blocking material is installed from the sealing agent coating equipment to the bonding equipment, and from the sealing agent coating equipment to the bonding equipment. Provided is a manufacturing line of a liquid crystal display element in which a UV blocking lamp is formed on the upper part.</p><p> If the UV blocking lamps are arranged in the entire manufacturing line of the liquid crystal display element, the above-mentioned problems do not occur. However, the brightness of the UV blocking lamp was so dark that it was difficult for the operator to observe the work process with the naked eye. Therefore, in the present invention, a UV blocking lamp is arranged on the upper part from the sealant application equipment to the coalescing equipment so that UV is not irradiated on the upper part of the equipment cover opened for discharging dust and the like. Is.</p><p> Further, in order to brighten the field of view of the entire production line, general lamps are arranged except for the UV blocking lamp, and the UV emitted from the general lamp irradiates the sealant on the substrate through the equipment cover on the side surface. In order to prevent this from happening, the equipment covers from the sealant application equipment to the coalescing equipment are made of UV blocking material.</p>

Hereinafter, desirable embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 shows the layout of the production line of the liquid crystal display element according to the embodiment of the present invention. As shown in FIG. 2, according to the embodiment of the present invention, first, the thin film transistor and the pixel electrode are formed in the lower portion. After the substrate is loaded into the first loading equipment 100 and the liquid crystal layer is formed by the liquid crystal dropping equipment 140, the substrate is temporarily waited in the first buffer 150. Then, the light-shielding film, the color filter layer, and the upper substrate on which the common electrode is formed are loaded into the second loading equipment 200, and after the sealant is applied by the sealant application equipment 220, a temporary standby is performed in the second buffer 250. To do. Then, the lower substrate and the upper substrate are moved to the bonding equipment 300 and bonded, and then the sealant is cured and bonded by the UV irradiation equipment 400.

On the other hand, as the sealant applied by the sealant application device 220, a monomer or oligomer in which an acrylic group is bonded to both ends is mixed with an initiator, and an acrylic group is provided at one end. A monomer or oligomer having an epoxy group bonded thereto may be mixed with an initiator at the other end. At this time, when a monomer or oligomer having an acrylic group bonded to one end and an epoxy group bonded to the other end is mixed with the initiator as the sealant, the epoxy group reacts by the UV irradiation. Therefore, after the UV irradiation step, a heating step is further performed to cure the sealant. Therefore, in this case, the thermosetting equipment is further arranged after the UV irradiation equipment 400.

Further, although not shown, the cell cutting equipment and the inspection equipment are further arranged after the UV irradiation equipment 400 or the thermosetting equipment. Such movement between process equipment is performed by the robot 600. At this time, the equipment covers (equipment covers in the shaded area) from the sealant application equipment 220 to the coalescing equipment 300 for applying the sealant to the upper substrate are made of a UV blocking material, preferably UV blocking acrylic. ..

A UV blocking lamp 700 is arranged above the sealant coating equipment 220 to the coalescing equipment 300. Further, although not shown, a spacer spraying device for forming a ball spacer may be further arranged between the sealant application device 220 and the coalescing device 300.

Further, when a contaminant is formed on the sealant, the adhesive strength between the two substrates is inferior. Therefore, although not shown, cleaning equipment for cleaning the substrate may be further arranged between the sealant application equipment 220 and the bonding equipment 300. Further, it is also possible to drop the liquid crystal on the upper substrate instead of dropping it on the lower substrate. In this case, the liquid crystal dropping equipment 140 may be arranged before and after the sealant coating equipment 220. When the liquid crystal dripping equipment 140 is placed after the sealant coating equipment 220, the equipment cover is formed of a UV blocking material.

For reference, there are screen printing method, dispenser method, etc. as a method for forming the sealant, but in the screen printing method, since the screen comes into contact with the substrate, the alignment film formed on the substrate may be damaged. When the area of the substrate is increased, the amount of loss of the sealant is large and it is uneconomical. Therefore, the dispenser method is desirable. Therefore, it is desirable that the sealing agent coating equipment 220 is also a dispensing equipment.

FIG. 3 shows the layout of the production line of the liquid crystal display element according to another embodiment of the present invention, which covers not only the sealant application equipment to the coalescence equipment but also the equipment cover from the coalescence equipment to the front of the UV irradiation equipment. Is the same as that of the above-described embodiment except that it is formed of a UV blocking material. Therefore, the same drawing reference numerals are given, and the description of the parts will be omitted.

When the lower substrate on which the liquid crystal layer is formed and the upper substrate coated with the sealant are coalesced and the liquid crystal layer comes into contact with the sealant, the liquid crystal is contaminated. Therefore, the liquid crystal is dropped on the central portion of the lower substrate at an excessive density so as to gradually spread so that the liquid crystal is distributed over the entire substrate at the same density.

When the liquid crystal is dropped by the above method, the UV irradiation step should be performed after the liquid crystal dropped with excessive density spreads to some extent in the central portion of the lower substrate and the desired cell gap is maintained. If the sealant is pre-cured after the bonding step and before the UV irradiation step, the desired cell gap cannot be obtained.

Therefore, in the layout of the production line of the liquid crystal display element according to another embodiment of the present invention shown in FIG. 3, the equipment covers from the joining process equipment 300 to the front of the UV irradiation process equipment 400 are UV-blocked and UV-blocked like acrylic. It is made of materials for UV protection, and the lamp at the top of the area also uses the UV blocking lamp 700.

FIG. 4 shows a layout of a production line for a liquid crystal display element according to still another embodiment of the present invention. As shown in FIG. 4, according to this embodiment, first, a lower portion in which a thin film transistor and a pixel electrode are formed is formed. After the substrate is loaded into the first loading equipment 100, the sealant is formed by the sealant application equipment 220, and the liquid crystal layer is formed by the liquid crystal dropping equipment 140, the first buffer 150 temporarily waits.

Then, the light-shielding film, the color filter layer, and the upper substrate on which the common electrode is formed are loaded into the second loading equipment 200, and temporarily stand by in the second buffer 250. At this time, a spacer spraying device may be further arranged between the second loading device 200 and the second buffer 250.

Then, the lower substrate and the upper substrate are bonded by the bonding device 300, and then the sealant is cured and bonded by the UV irradiation device 400. At this time, the equipment covers (equipment covers in the shaded area) from the sealant application equipment 220 to the coalescing equipment 300 for applying the sealant to the lower substrate are made of a UV blocking material, preferably UV blocking acrylic. .. A UV blocking lamp 700 is arranged above the sealant coating equipment 220 to the coalescing equipment 300.

Further, although not shown, spacer spraying equipment may be further arranged between the sealant application equipment 220 and the coalescing equipment 300 (in this case, between the second loading equipment 200 and the second buffer 250 described above). Spacer spraying equipment is not placed in). Further, a silver (Ag) coating device for applying a voltage to the common electrode of the upper substrate may be further arranged between the sealing agent coating device 220 and the coupling device 300. Since it is desirable that the silver (Ag) coating is performed by the dispenser method, it is desirable that the silver coating equipment is a dispensing equipment.

FIG. 5 shows the layout of the production line of the liquid crystal display element according to still another embodiment of the present invention, in which the equipment covers from the coupling equipment 300 to the front of the UV irradiation equipment 400 are formed of a UV blocking material. The same as the manufacturing line of the liquid crystal display element according to FIG. 4 described above, except that the lamp at the upper part of the region is formed as a UV blocking lamp 700.

As shown in FIG. 6, the UV blocking lamp 700 according to the embodiment of FIGS. 2 to 5 includes a UV blocking cover 701 and a lamp 702 housed therein.

FIG. 6 is a perspective view showing an example of the UV blocking lamp 700. The UV blocking lamp 700 includes a light source 702, and the light source 702 actually irradiates light including UV light, but the UV light is an object. The UV blocking cover 701 surrounds the light source 702 in order to prevent the light source from being irradiated to the light source 702. UV blocking acrylic is used as the UV blocking cover 701.

As described above, according to the present invention, the equipment cover from the sealant coating equipment to the bonding equipment is formed of the UV blocking material, and the UV blocking lamp is on the upper part from the sealing agent coating equipment to the bonding equipment. By arranging the sealant, the adhesive force between the lower substrate and the upper substrate is increased without the sealing agent being cured before the bonding step. In addition, the equipment cover from the coalescing equipment to the front of the UV irradiation equipment is formed of a UV blocking material, and the UV blocking lamp is placed in that area, so that the sealant is pre-cured before the UV irradiation process. The desired cell gap can be maintained without the need for it.

<figref num="1a">It is a perspective view which shows the manufacturing process of the liquid crystal display element by the liquid crystal dropping method in the related technology.</figref><figref num="1b">It is a perspective view which shows the manufacturing process of the liquid crystal display element by the liquid crystal dropping method in the related technology.</figref><figref num="1c">It is a perspective view which shows the manufacturing process of the liquid crystal display element by the liquid crystal dropping method in the related technology.</figref><figref num="1d">It is a perspective view which shows the manufacturing process of the liquid crystal display element by the liquid crystal dropping method in the related technology.</figref><figref num="2">It is a layout of the manufacturing line of the liquid crystal display element by one Embodiment of this invention.</figref><figref num="3">It is a layout of the manufacturing line of the liquid crystal display element by another embodiment of this invention.</figref><figref num="4">Layout of a manufacturing line for a liquid crystal display element according to still another embodiment of the present invention.</figref><figref num="5">Layout of a manufacturing line for a liquid crystal display element according to still another embodiment of the present invention.</figref><figref num="6">It is a block diagram of the UV blocking lamp used in each embodiment of this invention.</figref>

Code description

100: 1st loading part 200: 2nd loading section 220: Sealing agent application equipment 140: Liquid crystal dripping equipment 150: 1st buffer 250: 2nd buffer 300: Coalescence equipment 400: UV irradiation equipment 600: Robot