JPH04350626A - Structure of liquid crystal display panel - Google Patents

Abstract

PURPOSE:To correspond the liquid crystal panel having anisotropic conductive seals to fine patterns and to avert the defect that picture element electrodes conduct to each other by forming arbitrary resin layers on a substrate of the parts in contact with seals, thereby upraising these parts. CONSTITUTION:The electrodes 5 for picture elements are formed on the one substrate and the arbitrary resin layers 9 are formed between the substrate 4 of the parts on contact with the sealing materials 7 previously mixed with conductive grains 6 and the electrodes 5 for the picture elements. While the resins similar to protective films for color filters are formed as the resin layers 9 by a printing method, the kinds of the materials are not particularly limited, insofar as the materials withstand the process history during the production of the liquid crystal panel. An optical technique is also possible as the forming method and is similarly not particularly limited. The distance between the counter electrodes of the conductive parts is made smaller than the picture element parts in this way and the grain size of the conductive grains 6 in the sealing materials 7 to be used is reduced by as much as the upraising.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a liquid crystal display panel, and more particularly to a substrate structure in which electrical conduction between upper and lower substrates is achieved by mixing conductive particles in a sealing material.

0002

[Prior Art] In order to consolidate the externally sealed portions of the electrodes on opposing substrates for driving a liquid crystal panel onto one of the substrates, a conductive substance is sandwiched between the two substrates, and from one substrate On the other hand, there is a method of establishing continuity to the board. Regarding the material and structure of the conductive substance, there are methods to establish continuity using silver paste etc. in the liquid crystal holding area inside the seal,
There is a method of mixing conductive particles in the sealing material to create continuity at the sealing part. The latter method is more significant as it does not have a negative effect on the liquid crystal and does not impair the display appearance, and a specific proposal for this is introduced in Japanese Patent Publication No. 53-43306, and these are generally anisotropic conductive seals. It is called.

FIG. 5 shows a cross-sectional view of the structure of a liquid crystal panel using a conventional anisotropic conductive seal. A pixel electrode 2 and a conduction electrode 3 are formed on one substrate 1, and a pixel electrode 5 is similarly formed on the other substrate 4. Both substrates are bonded together using a sealing material 7 in which conductive particles 6 are mixed in advance. Liquid crystal layer thickness (
The distance between opposing electrodes (cell gap) is mainly defined by the spacer 8. In order to improve conduction reliability here, it is necessary to ensure as wide a contact area between the conductive particles 6, the pixel electrode 5, and the conduction electrode 3 as possible. Therefore, the diameter of the conductive particles 6 used is somewhat larger than the diameter of the spacer 8 or the required cell gap, and the conductive particles 6 have a certain degree of elasticity.

0004

[Problem to be Solved by the Invention] When the panel driving lead electrodes are concentrated on one side of the substrate, in an active matrix liquid crystal panel represented by a TFT, the driving elements are only on one side of the substrate, and the electrodes on the other substrate are Since a solid electrode common to the entire surface is sufficient, conduction between the electrodes only needs to occur at at least one location. However, in a simple matrix liquid crystal panel, the electrodes on both sides are patterned in units of pixel columns, and the electrodes on one side must be transferred to conductivity independently (without conduction between adjacent electrodes). Theoretically, an anisotropic conductive seal only provides conduction between opposing electrodes, and there is no conduction between adjacent electrodes on the same substrate, but this is because the diameter of the conductive particles is proportional to the distance between adjacent electrodes. This is clearly a small case. In reality, there is a possibility that the conductive particles are not completely dispersed in the sealing material and are clustered into several pieces. Furthermore, in actual bonding of both substrates, a sealing material containing conductive particles is laid out on one side of the substrate to be considerably thicker than the desired cell gap, and after bonding, pressure is applied to define the cell gap. Therefore, even if the conductive particles are completely dispersed in the sealant, if there are multiple conductive particles located in the layer thickness direction when the sealant is laid out on one side of the substrate, interparticle contact may occur after laminating and pressing. There is a possibility that FIG. 6 shows a partially enlarged sectional view of a conductive portion of a conventional liquid crystal display panel viewed from the lateral direction. In FIG. 6, conduction occurs between adjacent electrodes because the diameter of the conductive particles 6 set in accordance with the cell gap d is larger than the distance c between adjacent electrodes of the conduction electrode 3 or the pixel electrode 5. I have done it. From the above, in order to avoid conduction between adjacent electrodes on the same substrate, the distance between the electrodes needs to be at least larger than the diameter of the conductive particles, and considering the stability during mass production, the distance including the margin should be even larger. There will be a restriction that . This becomes a major problem when the pixel or electrode pitch of a liquid crystal panel is required to be finer or the panel external size is required to be smaller. In the case of fine-pitch electrodes, if the distance between adjacent electrodes is increased, the contact area with the conductive particles will be reduced accordingly, and the aperture ratio of the pixel portion will also be reduced. On the other hand, if the conductive particle density is increased too much, the probability of contact between particles increases. If both the area of the electrode under the seal and the distance between adjacent electrodes are increased in order to satisfy both conditions, the overall external shape of the panel will increase accordingly.

Furthermore, screen printing is often used as a method of laying out anisotropic conductive seals on a substrate, but if the screen is not cleaned or washed sufficiently, unnecessary parts of the substrate surface may be Conductive particles will adhere. As mentioned above, if the conductive particles are slightly larger than the cell gap, if they get into the liquid crystal holding area inside the sealant and cause electrical conduction between opposing electrodes in the pixel area, normal image display will not be possible. You will no longer be able to obtain it.

It is an object of the present invention to make a liquid crystal display panel having an anisotropic conductive seal using conductive particles compatible with miniaturization and miniaturization, and to prevent defects such as conduction between opposing electrodes inside the seal material. The purpose of the present invention is to provide a liquid crystal display panel structure that avoids this problem.

[0007]

[Means for Solving the Problems] The gist of the present invention to achieve the above object is to make a pair of substrates with electrodes arranged on their surfaces face each other, and use a sealing material mixed with conductive particles in advance. In the liquid crystal display panel made by laminating the substrates together, the distance between the two electrodes at the portion where the sealing material contacts is smaller than the distance in the liquid crystal holding area inside the sealing material. Further, an arbitrary resin layer is patterned and formed on at least one of the parts of the substrate that contacts the sealing material. Furthermore, the optional resin layer is a laminated color filter.

[0008]

[Operation] Since the distance between the opposing electrodes in the portion in contact with the seal is smaller than the distance between the electrodes inside the sealing material, the diameter of the conductive particles can be smaller than the cell gap. Therefore, even if the distance between adjacent electrodes is narrower than in the conventional structure, defects such as conduction between the electrodes will not occur. Furthermore, it is possible to avoid defects caused by conduction between opposing electrodes inside the seal portion.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 show cross-sectional views of the structure of a liquid crystal display panel according to the present invention. FIG. 1 corresponds to Example 1 shown below, and FIG. 2 corresponds to Example 2. The explanation will be given below according to the figures.

<Embodiment 1> In FIG. 1, one substrate 4
A pixel electrode 5 is formed on top of the pixel electrode 5, but an arbitrary resin layer is formed between the substrate 4 and the pixel electrode 5 in the portion that is in contact with the sealing material 7 in which conductive particles 6 are mixed in advance. 9 is formed. In implementing the structure shown in FIG. 1, the present inventor formed a resin equivalent to a color filter protective film by a printing method as an arbitrary resin 9. However, there are no particular limitations on the type of material as long as it can withstand the process history during manufacturing of the liquid crystal display panel (heat resistance, chemical resistance, etc.). In addition, optical methods (patterning using a photoreactive resin) can be used as a forming method, and the forming method is similarly not particularly limited as long as it can be formed at a desired position.

<Embodiment 2> In FIG. 2, a color filter 10 is formed on one substrate 4, and the pixel electrode 5 is a protective film 11 formed to cover the color filter 10. formed on top. The portion of the laminated color filter 12 that is in contact with the sealing material 7 on the substrate 4 is
Although the color filter 10 in the pixel portion is a single layer, it is stacked in multiple layers. In implementing the structure shown in FIG. 2, the inventor used photolithographic color filters as the color filter 10 and the laminated color filter 12. Normally, photolithographic color filter patterning involves exposing one optical mask to light for the first, second, and third colors at an alignment pitch that is equal to or an integral multiple of the color filter pitch. In the optical mask for a color filter in this example, a layout was laid out in advance so that the pattern for forming the laminated color filter 12 was formed at the position of the sealing material 7. Therefore, if the color filter 10 is patterned according to the normal process, a three-stage laminated color filter 12 will inevitably be formed, and the purpose can be achieved without any additional process compared to the conventional process. done. Note that even in the case of a color filter layout that requires a plurality of optical masks for color filters, the effects of the present invention can be satisfied as long as the structure is such that the color filters located in the seal portion are finally stacked. Therefore, there is no restriction that there must be only one mask. It goes without saying that the method of forming the color filter used is not limited to the photolithography method.

[0012] When the one-mask method is used in the second embodiment, strictly speaking, the layered color filter portion is
The structure is such that the position of each layer (color) is shifted by the alignment pitch of the color filter. FIG. 3 shows an enlarged partial cross-sectional view of a laminated filter of a liquid crystal display panel according to Example 2. In FIG. 3, if the alignment pitch a of the color filter is considerably smaller than the seal width b, a sufficient contact area between the conductive electrode 3 of the conductive particle 6 and the pixel electrode 5 can be secured. In addition, the edges of the laminated color filter 12 have a step-like shape because each layer is shifted by the alignment pitch, and the steps are gentle as a whole. This has the effect of reducing the incidence of disconnection. The inventor created a liquid crystal display panel in which the width b of the sealing material 7 was 1000 microns and the alignment pitch a was 30 microns.
It was confirmed that no disconnection occurred.

As shown in FIGS. 1 and 2, the cell gap is defined by the spacer 8 in both liquid crystal display panels, but in both cases, the diameter of the conductive grains 6 is smaller than the cell gap or the diameter of the spacer 8. ing. Therefore, even if unnecessary conductive particles 13 exist in the liquid crystal display area, this will not lead to a defect in which the opposing pixel electrodes 2 and 5 become electrically connected.

FIG. 4 is a partially enlarged sectional view of the conductive portion of the liquid crystal display panel according to the present invention, viewed from the lateral direction, and corresponds to the conventional example shown in FIG. 6. In FIG. 6, when the cell gap is d, conduction between adjacent electrodes is likely to occur because the diameter of the conductive grains 6 is larger than the distance c between adjacent electrodes. On the other hand, in FIG. 4, the diameter of the conductive particles 6 can be made smaller by the thickness of the resin layer 9 than the cell gap d, so even if the distance c between adjacent electrodes is set the same, conduction between adjacent electrodes will occur. It's hard to do.

[0015]

[Effects of the Invention] As described above, according to the present invention, by forming an arbitrary resin layer on the substrate in the portion in contact with the seal to raise the bottom, the distance between the electrodes in the conductive portion is made smaller than the distance between the electrodes in the pixel portion. I can do that. As a result, the diameter of the conductive grains within the anisotropic conductive seal can be made smaller by the amount that the bottom is raised. As a result, it is possible to narrow the distance between adjacent electrodes in the conductive part, making it possible to handle fine patterns that were previously impossible, and at the same time preventing defects such as conduction between adjacent electrodes even for non-fine patterns. It has the effect of reducing Furthermore, even if unnecessary conductive particles are mixed into the liquid crystal holding area, defects such as conduction between opposing pixel electrodes will not occur. Furthermore, when a color filter is used as the optional resin layer, the effects of the present invention can be obtained without any additional process to the conventional process. As described above, the effects of the present invention significantly contribute to the productivity and expandability of liquid crystal display panels using anisotropic conductive seals.

[Brief explanation of drawings]

FIG. 1 is a structural cross-sectional view of a liquid crystal display panel of Example 1 according to the present invention.

FIG. 2 is a structural cross-sectional view of a liquid crystal display panel according to Example 2 of the present invention.

FIG. 3 is a partially enlarged sectional view of a laminated filter according to Example 2 of the present invention.

FIG. 4 is a partially enlarged sectional view of a conductive part of a liquid crystal display panel according to the present invention.

FIG. 5 is a structural cross-sectional view of a liquid crystal panel using a conventional anisotropic conductive seal.

FIG. 6 is a partially enlarged sectional view of a conductive part of a conventional liquid crystal display panel.

[Explanation of symbols]

1, 4 Board 2 Pixel electrode 3, 5 Conductive electrode 6 Conductive particles 7 Seal material 8 Spacer 10 Color filter 12 Laminated color filter

Claims (3)

[Claims] 1. In a liquid crystal display panel manufactured by placing a pair of substrates having electrodes on their surfaces facing each other and bonding the substrates together using a sealing material mixed with conductive particles in advance, the sealing material is The distance between the two electrodes at the contact portion is
A structure of a liquid crystal display panel characterized in that the distance is smaller than the distance in the liquid crystal holding area inside the sealing material. 2. The structure of a liquid crystal display panel according to claim 1, wherein an arbitrary resin layer is patterned and formed on at least one of the substrates in a portion that contacts the sealing material. 3. The structure of a liquid crystal display panel according to claim 2, wherein the arbitrary resin layer is a laminated color filter.