Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
1998-11-24
2001-09-18
Malinowski, Walter J. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S141000
Reexamination Certificate
active
06292245
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display device(LCD), and more particularly to a liquid crystal display device with an in-plane switching(IPS) mode capable of preventing color shift occurrence.
2. Description of the Related Art
An IPS mode-LCD(refer to Principle and Characteristics of Electro-optical Behaviour with In-Plane Switching mode; Asia Display '95, pp 578-580, Hitachi, Japan) is proposed, to improve narrow view-angle in a twisted nematic(TN) mode-LCD. In this IPS mode-LCD, electrodes(both pixel and counter electrodes) for driving liquid crystal are formed on a lower substrate differently from the TN mode-LCD. The IPS mode-LCD has wide view-angle, since the liquid crystal molecules turn in keeping their long axes parallel to the plane of the substrate by a parallel electric field between electrodes.
However, in the IPS mode-LCD above described, the short axes of the liquid crystal molecules are viewed at one side while the long axes of them are viewed at another side, because they are arranged under the influence of only the parallel electric field. As a result, color shift which reveals different colors according to view angle occurs. For example, in case of viewing the short axes of the liquid crystal molecules, blue color having a short wavelength is displayed. On the other hand, in case of viewing the long axes of them, yellow color having a long wavelength is displayed, thereby deteriorating display quality.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to a liquid crystal display device with an in-plane switching mode capable of improving display quality by preventing color shift occurrence.
To accomplish this above object, a liquid crystal display device with an in-plane switching mode according to the present invention includes counter and pixel electrodes for driving liquid crystal formed on the same substrate. Here, when a voltage is applied to the counter and pixel electrodes, both a first electric field of a parallel direction and a second electric field of a vertical direction are formed between the electrodes.
In an embodiment of the present invention, the counter electrode includes an outer electrode having a rectangular picture frame form in a pixel region and an inner electrode disposed at a center of the outer electrode and having a reduced similar figure of the outer electrode, the portion of the inner electrode being connected to the outer electrode. Furthermore, the upper portion of the outer electrode is formed extending along the first direction to connect with another pixel region adjacent thereto.
The inner electrode includes four branches of oblique form disposed at the outside edges thereof, respectively and extending to the edges of the outer electrode. Moreover, one of the four branches is connected to the edge of the outer electrode. Furthermore, the inner electrode further includes oblique projection portions disposed at the inside edge thereof, respectively, and facing each other.
In an embodiment of the present invention, the pixel electrode includes:a first electrode disposed between the outer and inner electrode of the counter electrode and having a reduced a reduced similar figure of the outer electrode; a second electrode composed of four branches of oblique form disposed at the outside edges of the first electrode, respectively and extending the inside edges of the outer electrode; a third electrode overlapped with one of portions of the inner electrode of the parallel direction; a fourth electrode overlapped with the other of the inner electrode of the parallel direction, one side of the fourth electrode being obliquely extended to connect with the first electrode and overlapped with one of the branches of the inner electrode; and a fifth electrode arranged to the vertical direction and connecting the third electrode to the fourth electrode. Preferably, the first electrode is disposed at space between the outer and inner electrodes so that it divides the space into two equal parts. Furthermore, the fifth electrode is disposed so that it divides the space in the inner electrode into two equal parts.
Additional object, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
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patent: 5760857 (1998-06-01), Yanagawa et al.
patent: 5886762 (1999-03-01), Lee et al.
patent: 5977562 (1999-11-01), Hirakata et al.
patent: 09105908 (1997-04-01), None
Kim Hyang Yul
Lee Seung Hee
Hyundai Electronics Industries Co,. Ltd.
Ladas & Parry
Malinowski Walter J.
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