IPS-LCD having a third electrode having aperture and formed on counter substrate

• US 6,577,368 B1
• Filed: 11/03/1998
• Issued: 06/10/2003
• Est. Priority Date: 11/03/1997
• Status: Expired due to Term

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Na, Byoung-Sun, Kim, Dong-Gyu, Song, Jang-Kun, Chang, Jong-Woong, Lee, Kye-Hun, Lee, Hyun-Sik, Shim, Jung-Uk, Yuh, Jin-Tae
• Primary Examiner(s): TON, MINH TOAN T
• Application Number:
  US09/184,953
• Time in Patent Office: 1,680 Days
• Field of Search: 349/141, 349/38, 349/39, 349/139, 349/143
• 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 1/134372 for fringe field switching [FFS] where the common electrode is not patterned
• CPC Class Codes: G02F 1/134381 Hybrid switching mode, i.e. for applying an electric field with components parallel and orthogonal to the substrates

Abstract

A liquid crystal display having electrodes on a single substrate. A transparent planar electrode elongated in the transverse direction is formed on the inner surface of a substrate, and an insulating film is deposited thereon. A plurality of linear electrodes, which are elongated in the longitudinal direction and either transparent or opaque, are formed on the insulating film. Potential difference between the planar and the linear electrodes generated by applying voltages to the electrodes yields an electric field. The electric field is symmetrical with respect to the longitudinal central line of the linear electrodes and the longitudinal central line of a region between the linear electrodes, and has parabolic or semi-elliptical lines of force having a center on a boundary line between the planar and the linear electrodes. The line of force on the planar and the linear electrodes and on the boundary line between the planar and the linear electrodes has the vertical and the horizontal components, and the liquid crystal molecules are re-arranged to have a twist angle and an tilt angle. The polarization of the incident light varies due to the rearrangement of the liquid crystal molecules.

Claims

1. A liquid crystal display having a plurality of pixels, comprising:

first and second substrates facing each other;

a plurality of first electrodes formed on the first substrate;

a second electrode on the first substrate, the second electrode being insulated from the first electrodes, overlapping the first electrodes at least in part, and forming a continuous plane between the first electrodes; and

a third electrode having an aperture formed on the second substrate,

wherein a pixel has at least one of the first electrode and the second electrode.

2. The liquid crystal display of claim 1, wherein the second electrode of a pixel is connected to adjacent pixels.

3. The liquid crystal display of claim 2, wherein both the first electrodes and the second electrode comprise transparent conductive material.

4. The liquid crystal display of claim 1, wherein either of the first electrodes and the second electrode comprise transparent conductive material.

5. A liquid crystal display, comprising:

first and second substrates opposite each other;

a liquid crystal layer inserted between the first and the second substrates;

first and second electrodes which are formed on the first substrate and electrically insulated from each other; and

a third electrode having an aperture formed on the second substrate,

wherein a rearrangement region, where molecules of the liquid crystal layer are rearranged by an electric field generated when voltages are applied to the first and the second electrodes, is formed at least in part on the first or the second electrode, and a portion of the rearrangement region formed on the first or the second electrode serves as part of a display region.

6. The liquid crystal display of claim 5, wherein the molecules in the rearrangement region have a twist angle and a tilt angle.

7. The liquid crystal display of claim 5, wherein the first electrode overlaps the second electrode at least in part.

8. The liquid crystal display of claim 5, wherein the electric field has parabolic lines of force located between the first electrode and the second electrode, and the electric field on the first electrode or the second electrode has vertical and horizontal components.

9. The liquid crystal display of claim 5, wherein width of the first electrode is equal to or larger than width of the second electrode, and the rearrangement region on the first electrode serves a part of the display region.

10. The liquid crystal display of claim 9, wherein the first electrode is transparent.

11. The liquid crystal display of claim 10, further comprising first and second polarizing plates attached respectively to outer surfaces of the first substrate and the second substrate, and wherein light passing through one of the first and the second polarizing plates, passes through the display region and reaches the other of the first and the second polarizing plates.

12. The liquid crystal display of claim 5, wherein the liquid crystal layer has either positive or negative dielectric anisotropy.

13. The liquid crystal display of claim 12, wherein long axes of liquid crystal molecules in the liquid crystal layer are either perpendicular or parallel to the first and the second substrates when no voltage is applied to the first and the second electrodes.