Liquid crystal display and panel therefor

• US 7,206,048 B2
• Filed: 08/12/2004
• Issued: 04/17/2007
• Est. Priority Date: 08/13/2003
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Song, Jang-Kun
• Primary Examiner(s): Ton; Toan
• Assistant Examiner(s): DUONG, TAI V
• Application Number:
  US10/916,518
• Publication Number:
  US 20050036091A1
• Time in Patent Office: 978 Days
• Field of Search: 349/38, 349/39, 349/43, 349/48, 349/110, 349/128, 349/129, 349/143, 349/144, 349/146, 349/42, 345/87, 345/92, 313/500, 313/505
• US Class Current: 349/129
• CPC Class Codes: G02F 1/133707 Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/134336 Matrix
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 1/13624 having more than one switching element per pixel
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 2201/123 pixel
• CPC Class Codes: H01L 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52

Abstract

A flat panel display having an improved picture quality is disclosed. In one embodiment, a first pixel electrode and a second pixel electrode are formed in each subpixel area. The electrodes enclose an open space (gap) such that their outer boundary has a substantially rectangular shape. The flat panel display may also include a capacitance electrode coupled to the second pixel electrode to form a coupling capacitor. In use, the coupling capacitor operates such that a magnitude of a voltage applied to the first pixel electrode is lower than an applied data voltage, and a magnitude of a voltage applied to the second pixel electrode is higher than an applied voltage. The different voltages operate such that a tilt direction of LC molecules disposed above the first pixel electrode differs from a tilt direction of LC molecules disposed above the second pixel electrode.

Claims

1. A flat panel display, comprising:

one or more pixel areas, each pixel area including one or more subpixel areas;

in each subpixel area, a first pixel electrode and a second pixel electrode that engage with each other and enclose a gap such that their outer boundary has a substantially rectangular shape,

wherein the first pixel electrode includes a pair of right-angled triangular shaped portions facing one or more oblique edges of the second pixel electrode and further includes a longitudinal portion facing a side edge of the second pixel electrode,

wherein the second pixel electrode has a shape that approximates an equilateral trapezoid.

2. The flat panel display of claim 1, wherein the second pixel electrode has an edge thereof disposed proximate a first storage electrode and another edge disposed proximate a second storage electrode.

3. The flat panel display of claim 1, further comprising a common electrode disposed above the subpixel areas, the common electrode formed of a transparent conductive material and having at least one cutout therein.

4. The flat panel display of claim 1, wherein the gap is disposed between at least one cutout formed in the common electrode and an opening that separates a pixel area from another of the one or more pixel areas.

5. The flat panel display of claim 3, further comprising:

a liquid crystal (LC) layer disposed between the common electrode and the one or more subpixel areas, the LC layer including a plurality of LC molecules.

6. The flat panel display of claim 1, further comprising:

a coupling capacitor electrode capacitively coupled to the second pixel electrode to form a coupling capacitor.

7. The flat panel display of claim 6, wherein:

the coupling capacitor electrode is electrically connected to the first pixel electrode using a thin film transistor, and

the coupling capacitor alters a magnitude of an applied data voltage such that a magnitude of a voltage applied to the first pixel electrode is less than the applied data voltage, and a magnitude of a voltage applied to the second pixel electrode is higher than the applied data voltage.

8. The flat panel display of claim 7, wherein the difference in the voltages applied to the first and second pixel electrodes reduces distortion of gamma curves and improves picture quality.

9. The flat panel display of claim 1, wherein the second pixel electrode includes a cutout that bisects the second pixel electrode into a lower portion and an upper portion.

10. The flat panel display of claim 2, wherein a ratio of a surface area of the first pixel electrode to a surface area of the second pixel electrode is approximately in the range of about 50:

50 to about 80;

20.

11. The flat panel display of claim 2, wherein the gap has a width in the range of approximately 2–

5 microns.

12. A flat panel display, comprising:

one or more pixel areas, each pixel area including one or more subpixel areas;

in each subpixel area, a first pixel electrode and a second pixel electrode that engage with each other and enclose a gap such that their outer boundary has a substantially rectangular shape; and

a coupling capacitor electrode capacitively coupled to the second pixel electrode to form a coupling capacitor;

wherein the coupling capacitor electrode is electrically connected to the first pixel electrode using a thin film transistor, and

wherein the coupling capacitor alters a magnitude of an applied data voltage such that a magnitude of a voltage applied to the first pixel electrode is less than the applied data voltage, and a magnitude of a voltage applied to the second pixel electrode is higher than the applied data voltage.

13. The flat panel display of claim 12, wherein the first pixel electrode includes a pair of right-angled triangular shaped portions facing one or more oblique edges of the second pixel electrode and further includes a longitudinal portion facing a side edge of the second pixel electrode.

14. The flat panel display of claim 12, wherein the second pixel electrode has a shape that approximates an equilateral trapezoid.

15. The flat panel display of claim 12, wherein a ratio of a surface area of the first pixel electrode to a surface area of the second pixel electrode is approximately in the range of about 50:

50 to about 80;

20.

16. The flat panel display of claim 12, wherein a tilt direction of liquid crystal (LC) molecules disposed above the first pixel electrode differs from a tilt direction of LC molecules disposed above the second pixel electrode.

17. The flat panel display of claim 12, wherein the gap has a width in the range of approximately 2–

5 microns.

18. A flat panel display, comprising:

a common electrode formed of a transparent conductive material and having at least one cutout therein;

one or more pixel areas positioned under the common electrode, each pixel area including one or more subpixel areas;

a liquid crystal (LC) layer disposed between the common electrode and the one or more subpixel areas, the LC layer including a plurality of LC molecules

in each subpixel area, a first pixel electrode and a second pixel electrode that engage with each other and enclose a gap such that their outer boundary has a substantially rectangular shape,

wherein the first pixel electrode includes a pair of right-angled triangular shaped portions facing one or more oblique edges of the second pixel electrode and further includes a longitudinal portion facing a side edge of the second pixel electrode,

wherein the second pixel electrode has a shape that approximates an equilateral trapezoid, and has an edge thereof disposed proximate a first storage electrode and another edge disposed proximate a second storage electrode, and

wherein the gap is disposed between the at least one cutout formed in the common electrode and an opening that separates a pixel area from another of the one or more pixel areas.

19. The flat panel display of claim 18, wherein a voltage applied to the first pixel electrode is lower than a voltage applied to the second pixel electrode, such that a tilt direction of LC molecules disposed above the first pixel electrode differs from a tilt direction of LC molecules disposed above the second pixel electrode.

20. The flat panel display of claim 19, wherein the gap includes a pair of oblique lower and upper portions, each portion having a substantially uniform width and making an angle of about 45 degrees relative to one or more gate lines.

21. The flat panel display of claim 20, wherein the gap further includes a longitudinal portion having a substantially uniform width.

22. The flat panel display of claim 21, wherein the oblique portions are each longer than the longitudinal portion.

23. The flat panel display of claim 19, wherein the second pixel electrode includes a cutout that bisects the second pixel electrode into a lower portion and an upper portion.

24. The flat panel display of claim 23, wherein the cutout has an inlet from an outer edge of the second pixel electrode, and a pair of inclined edges substantially parallel a lower oblique portion and upper oblique portion of the gap.

25. The flat panel display of claim 19, further comprising:

a light blocking member formed on a transparent insulating substrate disposed above the common electrode, wherein the light blocking member includes a plurality of openings that face the first and second pixel electrodes.

26. The flat panel display of claim 25, further comprising:

a plurality of color filters formed on the transparent insulating substrate and disposed substantially in the plurality of openings formed in the light blocking member.

27. The flat panel display of claim 26, wherein the plurality of color filters extend substantially along a longitudinal direction of the first and second pixel electrodes, and a color of each of the plurality of color filters represents one of a primary color such as red, green, or blue.

28. The flat panel display of claim 18, further comprising:

a coupling capacitor electrode capacitively coupled to the second pixel electrode to form a coupling capacitor.

29. The flat panel display of claim 28, wherein:

the coupling capacitor electrode is electrically connected to the first pixel electrode using a thin film transistor, and

the coupling capacitor alters a magnitude of an applied data voltage such that a magnitude of a voltage applied to the first pixel electrode is less than the applied data voltage, and a magnitude of a voltage applied to the second pixel electrode is higher than the applied data voltage.

30. The flat panel display of claim 29, wherein the difference in the voltages applied to the first and second pixel electrodes reduces distortion of gamma curves and improves picture quality.

31. The flat panel display of claim 29, wherein the data voltage is approximately equal to about 2.0 V, and the voltage difference between the first pixel electrode and the second pixel electrode is approximately equal to about 0.59 V.

32. The flat panel display of claim 29, wherein the data voltage is approximately equal to about 5.0 V, and a voltage drop of the first pixel electrode is approximately equal to about 0.55V, and a voltage raise of the second pixel electrode is approximately equal to about 0.64V.

33. The flat panel display of claim 29, wherein a ratio of a surface area of the first pixel electrode to a surface area of the second pixel electrode is approximately in the range of about 50:

50 to about 80;

20.

34. The flat panel display of claim 33, wherein the ratio is approximately 70:

30.

35. The flat panel display of claim 18, wherein the gap has a width in the range of approximately 2–

5 microns.