1. Field of the Invention
The present invention relates generally to a liquid display device and a method of manufacturing the same, and more particularly to improving screen grade by providing the improved post spacer structure in the liquid display device.
2. Description of the Prior Art
In the conventional liquid display device employing a post spacer, a color filter substrate is fabricated by forming, in turn, a black matrix on the glass substrate, forming red, green and blue color filters, forming an overcoating layer, forming an indium tin oxide (ITO) layer, and forming a post spacer.
In here, the ITO layer is formed in the mode using a vertical electric field, such as a twisted nematic (TN) mode, not in the mode using a parallel electric field, such as a fringe-field switching (FFS) or in-plane switching (IPS).
However, according to this liquid crystal display device of the prior art as shown in
To solve the above-mentioned problem, a prior invention as shown in
However, even the prior invention mentioned immediately above also has many problems. Even though the post spacers of the prior invention are designed to be disposed in one direction depending on the processing direction in a polyimide (PI) coating or rubbing process (as shown in
Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide a liquid crystal display device and a method for manufacturing the same which employ post spacers enabling liquid crystal to flow smoothly.
Another object of the present invention is to provide a liquid crystal display device and method for manufacturing the same capable of preventing defects in polyimide (PI) coating and scratches.
In order to accomplish these objects, a method for manufacturing a liquid crystal display device according to the present invention comprises the steps of: preparing a transparent insulation substrate; forming a black matrix on the substrate; forming red, green and blue color filters in each of the sub pixels defined by the black matrix; forming an overcoating layer on the color filters and the black matrix; forming a post spacer surrounding the four sides of each of the sub-pixels wherein red, green and blue color filters formed and having a groove on the middle portion of each of the sides surrounded; and forming a liquid crystal layer consisting of a polymer dispersed liquid crystal on the overcoating layer including the post spacer.
Furthermore, a liquid crystal display device according to the present invention comprises: a transparent insulation substrate; a black matrix formed on the substrate; red, green and blue color filters formed in each of the sub pixels defined by the black matrix; an overcoating layer formed on the color filters and the black matrix; a post spacer surrounding the four sides of each of the sub-pixels wherein red, green and blue color filters formed and having a groove on the middle portion of each of the sides surrounded; and a liquid crystal layer consisting of a polymer dispersed liquid crystal on the resulting substrate including a post spacer.
The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:
Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.
In a method for manufacturing a liquid crystal display device according to a first embodiment of the present invention, a black matrix of resin or chrome (Cr) or other suitable material well known to those skilled in the pertinent art is formed on a transparent insulation substrate such as glass. Then, red, green and blue filters are formed in each of the sub pixels defined by the black matrix. An overcoating layer is formed on the entire substrate including the color filters and the black matrix.
An ITO layer is formed in the mode using a vertical electric field, such as a twisted nematic (TN) mode, not in the mode using a parallel electric field, such as a fringe-field switching (FFS) or in-plane switching (IPS).
Subsequently, a photoresist is formed on the overcoating layer, and then exposed in the presence of a patterned mask, thereby forming a post spacer. The post spacer has a thickness ranging from approximately 2 to 10 μm.
Here, as shown in
Each of the sub-pixels of color filters 120a, 120b, 120c are defined or bound by black matrix 110 on the same layer as this is shown in
Therefore, as shown in
The sub-pixel space as shown in
As shown in
The top layer of each of
Further, it is preferred that polymer dispersed liquid crystal (PDLC), in which polymer and liquid crystal are mixed and dispersed, is used for the liquid crystal layer (not shown). In this case, a polyimide (PI) coating failure or a scratch can be prevented, which may be generated during a subsequent PI coating or rubbing process, resulting from height differences. Specifically, since the PDLC is mixed with polymer and liquid crystal at a constant rate, the liquid crystal is capable of being aligned or driven without PI coating and aligning processes.
Also, it is preferred that the liquid crystal layer (not shown) is formed in a one-drop filling process, because this process can facilitate a smooth flow of the liquid crystal to form a uniform cell gap.
In addition, since the post spacers 140 are separated by a groove 111 and the sub-pixel spaces and surrounding each of the sub pixel spaces, it is easy for the liquid crystal to smoothly flow over the entire or largely defined area of the liquid crystal layer through the sub-pixel spaces and grooves 111, and this provides one of many significant advantages of the present invention over prior art.
As shown in
In the method of manufacturing a liquid crystal display device according to a second embodiment of the present invention, as shown in
Next, an overcoating layer 230 is formed on the layer of the black matrix 210 and the color filters 220. And then, an ITO layer (not shown) is formed in the mode using a vertical electric field, such as a twisted nematic (TN) mode, not in the mode using a parallel electric field, such as a fringe-field switching (FFS) or in-plane switching (IPS).
Subsequently, a photosensitive polymer acting as an alignment layer is applied on the overcoating layer 230, and then exposed to light in the presence of a half tone mask to form post spacers 240. The post spacers 240, through the properties of their materials, have a double function as an alignment layer as well as an overcoating layer.
Herein, the detailed description on the other processes will be omitted, because they are the same as those of the first embodiment of the present invention. The structures of the sub-pixel spaces and grooves are not shown in
As seen from the above, a liquid crystal display device and method for manufacturing the same according to the embodiments of the present invention can obtain effects as following.
According to the present invention, it is possible to enable liquid crystal to flow smoothly due to the grooves formed in the post spacer whose area is big, enough to prevent defects in the polyimide (PI) coating and scratches by using a polymer dispersed liquid crystal (PDLC), and to decrease the time for injecting liquid crystal by using a one-drop filling (ODF) process. Therefore, present invention provides an improved screen grade, the decreased number of processing steps, as well as the cost-effective processing steps in manufacturing the liquid crystal display.
Although a preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
Number | Date | Country | Kind |
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2002-5077 | Jan 2002 | KR | national |
Number | Date | Country | |
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Parent | 10317794 | Dec 2002 | US |
Child | 11054187 | Feb 2005 | US |