Liquid crystal display device having comblike bent interdigital electrodes

• US 6,288,763 B1
• Filed: 09/03/1998
• Issued: 09/11/2001
• Est. Priority Date: 04/16/1996
• Status: Expired due to Term

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: Obayashi Seikou Company Limited
• Inventors: Hirota, Naoto
• Primary Examiner(s): Malinowski, Walter J.
• Application Number:
  US09/142,448
• Time in Patent Office: 1,104 Days
• Field of Search: 349/42, 349/43, 349/139, 349/141
• US Class Current: 349/141
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence

Abstract

An active matrix type liquid crystal display device of the transverse electric field system, wherein display pixels are constituted on a substrate by scanning signal lines, video signal lines, pixel electrodes and active elements in order to obtain an image having good visual field angle characteristics and a high display quality with less residual image. A liquid crystal alignment film is formed directly or via an insulating layer on the substrate. The substrate is opposed to another substrate having a color filter forming a liquid crystal alignment film, and the liquid crystal layer is held by the two substrates. The electrodes and the active elements are so constituted that an electric field can be applied to the liquid crystal layer substantially in parallel with the substrate. The electrodes and the active elements are connected to an external control means capable of arbitrarily controlling the applied electric field depending upon a display pattern. The liquid crystal display device is further provided with a polarizer means capable of changing the optical characteristics depending upon the state of alignment of the liquid crystal layer. The video signal lines and the pixel electrodes are bent within a range of 1 to 30 degrees relative to the direction of liquid crystal alignment.

Claims

1. An active matrix liquid crystal display device, comprising:

a pair of substrates, at least one of which is transparent;

a liquid crystal composite layer provided between said substrates and having a positive dielectric constant;

a plurality of scanning lines and video signal lines provided in a matrix manner on a surface of one of said substrates facing the other substrate;

two sets of pixel electrodes, each having a comb like shape and interdigitally aligned with one another, one set of said pixel electrodes being connected to a common electrode;

an active element connected to said pixel electrodes, said scanning lines and said video signal lines, respectively;

wherein each of said pixel electrodes is inclined in first and second directions to form a zigzag shape which is symmetrical relative to the alignment direction of the liquid crystal, where the first direction of said pixel electrodes is within an angle ranging between plus 1-30 degrees relative to the alignment direction of the liquid crystal, while the second direction of the pixel electrodes is within an angle ranging between minus 1-30 degree relative to the alignment direction with substantially the same absolute angle with that of the first direction, thereby making the first and second directions symmetrical relative to said alignment direction.

2. A liquid crystal display device having an active element as defined in claim 1, wherein said video signal lines are inclined in first and second directions in parallel with said pixel electrodes to form a zigzag shape which is symmetrical relative to said alignment direction where the first direction of said video signal lines is within an angle ranging between plus 1-30 degrees relative to the alignment direction of the liquid crystal, while the second direction of said video signal lines is within an angle ranging between minus 1-30 degrees relative to the alignment direction with substantially the same absolute angle with that of said first direction, thereby making said first and second directions symmetrical relative to said alignment direction.

3. A liquid crystal display device having an active element as defined in claim 2, further comprising a color filter and a black mask which are zigzag shaped in the first and second directions with the angles identical to that of the video signal lines.

4. A liquid crystal display device having an active element as defined in claim 1, further comprising a color filter and a black mask which are zigzag shaped in the first and second directions with the angles identical to that of the pixel electrodes.