JP4990871B2 - Manufacturing method of liquid crystal display device - Google Patents

Description

  The present invention relates to a liquid crystal display device.

  In recent years, a liquid crystal device called a horizontal electric field method has been spotlighted. This method is a method in which the direction of the electric field applied to the liquid crystal is substantially parallel to the substrate, and has an advantage that visual characteristics can be improved as compared with a TN (Twisted Nematic) method or the like. As this horizontal electric field type liquid crystal device, a liquid crystal device such as an IPS (In-Plane Switching) method or a FFS (Fringe Field Switching) method is known.

  In the horizontal electric field method, an electrode for selecting a display pixel, a transistor, and a common electrode are provided on a first glass substrate of two glass substrates arranged to face each other with a liquid crystal composition therebetween, and an electric field is applied between the two electrodes. In addition, the molecules of the liquid crystal composition are changed in the horizontal direction to control the transmitted light, and the molecular length of the liquid crystal composition has little change with respect to the display surface. The disadvantage of angular characteristics is improved.

  However, in this horizontal electric field method, when a charge such as static electricity is charged on the second glass substrate to which an electric field is not originally applied, if the static charge remains on the glass surface, an electric field is generated in the vertical direction and the liquid crystal Since the orientation of the molecules is fixed in a specific direction, the liquid crystal molecules cannot be controlled and display unevenness occurs. As described above, since the horizontal electric field liquid crystal panel is liable to cause display defects due to static electricity, a method for removing the influence of static electricity is required.

In order to solve this problem, conventionally, a transparent electrode is provided on the outer surface of the second glass substrate to which an electric field is not originally applied, and is connected to another electrode having a constant potential such as a ground potential. Since there is a step such as the thickness of the second glass substrate between the outer surface of the second glass substrate and another electrode having a constant potential, the transparent electrode is made of a conductive spring (see, for example, Patent Document 1). ), Conductive paste (for example, refer to Patent Document 2), anisotropic conductor (for example, refer to Patent Document 3), conductive cable (for example, refer to Patent Document 4 and Patent Document 5), etc. It was connected to other electrodes on the first glass substrate.
JP 2000-250062 (page 3 to page 4, FIG. 1) JP 2008-145686 A (page 4, FIG. 1) Japanese Patent Laying-Open No. 2006-146155 (page 4 to page 6, FIG. 2) Japanese Patent Laid-Open No. 2001-108958 (page 3 to page 4, FIG. 1) JP 2001-147441 A (second page, FIG. 1)

  However, in an example in which the transparent electrode and the bezel are connected by a conductive spring or a conductive buffer material, stress may be applied to the glass substrate and display unevenness may occur. In an example in which a conductive paste is applied and connected or connected with a conductive cable, the connecting portion needs to be thick and the entire thickness increases. In addition, there is a problem that the weight of the connecting member is increased for products and parts that are required to be light, thin, and small.

  The transparent electrode for preventing static electricity provided on the outer surface of the second glass substrate of the pair of glass substrates arranged via the liquid crystal composition is used as the ground electrode provided on the terminal portion of the first glass substrate having a step. As a means for connection, the conductive paste is printed. As a printing method, a method capable of printing on a stepped surface such as inkjet printing or pad printing (octopus printing) is used. In addition, a gap of about 2 to 6 μm, which is the same as the thickness of the liquid crystal composition, is present between the pair of glass substrates disposed via the liquid crystal composition. For this reason, printing is performed including the surface of the insulating mold material applied to the IC chip mounted on the first glass substrate. Alternatively, the IC chip mold material is filled in the gap between the two glass substrates, and the conductive mold is connected via the surface of the insulating mold material. As a result, the molding material is filled in the gap between the corner portions of the step portions of the two glass substrates, so that the conductive paste can be printed more reliably.

  An antistatic transparent electrode provided on an outer surface of a first glass substrate of a liquid crystal display panel in which a liquid crystal composition is sealed between a pair of glass substrates is connected to a ground electrode on a second glass substrate having a step. In this case, the thickness of the electrode connection portion between the static electricity preventing transparent electrode and the ground electrode can be reduced by using the printed conductive paste. Furthermore, since the amount of the conductive material used can be suppressed, an increase in weight and an increase in product cost can be suppressed.

  According to the method for manufacturing a liquid crystal display device of the present invention, a liquid crystal is formed between a first substrate having a terminal portion on which an earth electrode is formed and a second substrate having an antistatic transparent electrode formed on the outer surface. It was decided to include a step of creating an encapsulated liquid crystal display panel and a connection step of electrically connecting the antistatic transparent electrode and the grounding electrode by printing a conductive material. By this method, the thickness of the conductive material can be reduced.

  Further, a molding process step of applying an insulating mold material to the liquid crystal display panel before the connecting step is provided, and the conductive material is printed via the insulating mold material. Thereby, since the gap between the stepped portions of the two glass substrates is filled with the molding material, the conductive paste can be printed more reliably.

  Alternatively, an IC chip is mounted on the terminal portion of the first substrate, and includes a mold processing step of applying an insulating mold material around the IC chip of the liquid crystal display panel before the connection step. The conductive material was printed via the mold material.

  Embodiments of the present invention will be specifically described below with reference to the drawings.

  Example 1 will be described with reference to FIG. FIG. 1A is a front view of a horizontal electric field type liquid crystal display device of this embodiment. FIG.1 (b) shows the cross section in AB of Fig.1 (a). A liquid crystal composition is provided between a pair of opposing first glass substrate 4 and second glass substrate 5, and a polarizing plate 8 is attached on the second glass substrate. An antistatic transparent electrode 1 is provided on the second glass substrate 5. An antistatic potential supply electrode 2 is formed on a terminal portion on the first glass substrate 4. Further, the antistatic potential supply electrode 2 is electrically connected to the GND via a flexible substrate (not shown). An IC chip 6 for driving liquid crystal is COG-mounted on the first glass substrate 4. A resin mold 7 is applied around the IC chip 6. The conductive paste 3 is printed via the upper surface of the resin mold 7 between the antistatic potential supply electrode 2 on the first glass substrate 4 and the antistatic transparent electrode 1 on the second glass substrate to connect the electrodes. The antistatic potential supply electrode 2 and the antistatic transparent electrode 1 are electrically connected. As a means for printing the conductive paste 3, an ink jet printing method or a vat printing method is used. By using inkjet printing and vat printing, it is possible to print not only on a flat surface but also on a stepped surface. Thus, when the conductive paste is used for the purpose of preventing static electricity, the resistance value of the conductive paste does not need to be particularly low. For this reason, in this embodiment, a conductive paste containing a carbon-based conductive material is used. However, a metal paste such as a silver paste or a copper paste having a low resistance value may be used. The conductive paste 3 has a thickness of about 15 μm to 60 μm immediately after printing, but has a thickness of about 5 μm to 20 μm after drying. By using such a printing method, the usage amount of the conductive paste can be suppressed to a very small amount, and the thickness of the electrode connection portion can be reduced. Further, since the printing position accuracy is good, the printing width can be set to about 0.5 mm to 2 mm. In this embodiment, the printing width is 0.5 mm. Further, since the area of the antistatic potential supply electrode 2 printed on the first glass substrate 4 can be reduced corresponding to the printing width of the conductive paste, the layout of the electrode wiring on the first glass substrate can be reduced. You can increase the degree of freedom. In this way, when the transparent electrode of the second glass substrate is electrically connected to the electrode on the first glass substrate, the conductive paste is printed by the ink jet printing method or the vat printing method, so that the thickness of the step portion is small. An electrode connection portion can be provided, and a horizontal electric field type liquid crystal display device in which display unevenness does not occur without applying stress to the glass substrate can be realized.

Although the conductive paste 3 is printed in a straight line in FIG. 1, it may be printed in a hook shape as shown in FIG. Thus easily set the location to provide an ESD potential subjected feeding electrode 2 by printing the key shape.

  A second embodiment will be described with reference to FIG. FIG. 3A is a front view of the horizontal electric field type liquid crystal display device of this embodiment. FIG. 3B shows a cross section taken along AB in FIG. The method for producing the liquid crystal panel is the same as in the first embodiment. An antistatic transparent electrode 1 is provided on the upper surface of the second glass substrate 5, and an antistatic potential supply electrode 2 is provided on a terminal portion on the first glass substrate 4. The second embodiment is different from the first embodiment in that the resin mold 7 is filled in the gap between the first glass substrate 4 and the second glass substrate 5 constituting the liquid crystal panel.

  An IC chip 6 for driving liquid crystal is COG-mounted on the first glass substrate 4 of the liquid crystal display device as in the first embodiment. In Example 2, the resin mold 7 is applied around the IC chip 6 using a dispenser. At this time, the resin mold 7 is filled using a dispenser so as to close the gap between the first glass substrate 4 and the second glass substrate 5. A route through the upper surface of the resin mold 7 in which the antistatic potential supply electrode 2 on the first glass substrate 4 and the antistatic transparent electrode 1 on the second glass substrate 5 are applied to close the gap between the glass substrates. Then, the conductive paste 3 is printed. An ink jet printing method or a butt printing method is used as the printing means. By using inkjet printing and vat printing, it is possible to print on a stepped surface as well as a flat surface.

  In the present embodiment, since the resin mold is provided in a wider range than in the first embodiment, the conductive paste printing area and the place where the antistatic potential supply electrode 2 is installed are located at the end of the glass substrate. It can be expanded to near. Therefore, the degree of freedom in the layout of the electrode wiring on the first glass substrate can be further increased.

  In this embodiment, the COG mounting type liquid crystal display device is described as an example, but a liquid crystal display device in which an IC for driving liquid crystal is mounted on an FPC or a rigid PCB, or a liquid crystal driving circuit is formed on a glass substrate by a TFT method. The same effect can be obtained with a liquid crystal display device.

  The horizontal electric field type liquid crystal display device of the present invention can be used as a display device with a high viewing angle in various applications such as a mobile phone, a liquid crystal television, and an industrial equipment display device.

It is a figure which shows the liquid crystal display device concerning one embodiment of this invention. It is a figure which shows the liquid crystal display device concerning another one Embodiment of this invention. It is a figure which shows the liquid crystal display device concerning another one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrostatic prevention transparent electrode 2 Antistatic potential supply electrode 3 Conductive paste 4 1st glass substrate 5 2nd glass substrate 6 Liquid crystal drive IC chip 7 Resin mold 8 Polarizing plate

Claims (4)

A first glass substrate having a terminal portion which is electrode formed ground, between the second glass substrate having the transparent electrode antistatic formed on the outer surface, to create a liquid crystal display panel by sealing liquid crystal Process,
Supplying an insulating mold material to the first glass substrate;
In order to electrically connect the grounding electrode and the transparent electrode above antistatic, wherein you printing a conductive material on the ground electrode and the transparent electrode the antistatic through a top of the molding material connecting step A method for manufacturing a liquid crystal display device. The method for manufacturing a liquid crystal display device according to claim 1 , wherein the molding material is supplied so as to fill a gap between the first glass substrate and the second glass substrate. Wherein the terminal portion of the first glass substrate and IC chip is mounted, The method according to claim 1, wherein the molding material is characterized Rukoto supplied around the IC chip. The method according to any one of claims 1 to 3 the thickness of the connecting process with the printed electrically conductive material is characterized in that it is a 20μm from 5 [mu] m.

Images