Electrophoretic display device having improved color gamut

• US 8,179,365 B2
• Filed: 10/22/2008
• Issued: 05/15/2012
• Est. Priority Date: 10/26/2007
• Status: Expired due to Fees

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Jeong-Kuk, Kim, Sung-Jin, Park, Jae-Byung, Lee, Son-Uk, Lee, Seul
• Primary Examiner(s): Wang, Quan-Zhen
• Assistant Examiner(s): DAVIS, TONY O
• Application Number:
  US12/255,900
• Publication Number:
  US 20090109172A1
• Time in Patent Office: 1,301 Days
• Field of Search: 345/173, 345/107, 359/296
• US Class Current: 345/107
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 3/344 based on particles moving in a fluid or in a gas, e.g. electrophoretic devices electrophoretic devices per se G02F1/167

Abstract

An electrophoretic display device has a first substrate that defines a plurality of sub-pixel areas; with shaped pixel electrodes formed in the sub-pixel areas. A second substrate is attached in facing relation to the first substrate during mass production. The second substrate has color filters of different colors (e.g., R, G, B). The areas of the color filters are less than the areas of their corresponding sub-pixel electrodes so as to thereby avoid or reduce a color mixture effect that may arise from mass production misalignment between the first and second substrates. In one class of embodiments, area consumed by the color filters is less than about 75% but more than about 45% of area consumed by respective pixel areas. Each pixel area comprises a white (W) sub-pixel area in addition to the differently colored sub-pixel areas (e.g., R, G, B).

Claims

1. An electrophoretic display device, comprising:

a first substrate comprising a plurality of pixel areas, each pixel area of the plurality of pixel areas including a plurality of sub-pixel areas, the plurality of pixel areas including a first pixel area, the first pixel area including a first sub-pixel area, a second sub-pixel area, a third sub-pixel area, and fourth sub-pixel area for displaying a first color, a second color, a third color, and a fourth color, respectively, wherein the first, second, and third sub-pixel areas have the same size, and the fourth sub-pixel area is of lesser area than each of the first, second, and third sub-pixel areas;

sub-pixel electrodes formed in respective ones of the plurality of sub-pixel areas of the first substrate, the sub-pixel electrodes including a first sub-pixel electrode; and

a plurality of differently colored sub-color filters corresponding to the sub-pixel electrodes and formed in a second substrate facing the first substrate, the plurality of differently colored sub-color filters including a first sub-color filter, where an area of the first sub-color filter is substantially less than an area of the first sub-pixel electrode.

2. The electrophoretic display device of claim 1, wherein the sub-color filters comprise first to third color filters for displaying red, green, and blue, respectively.

3. The electrophoretic display device of claim 2, wherein the first to fourth sub-pixel areas are configured for displaying red, green, blue, and white, respectively.

4. The electrophoretic display device of claim 3, wherein first to fourth pixel electrodes are formed in the first to fourth sub-pixel areas and have the same shape as the first to fourth sub-pixel areas.

5. The electrophoretic display device of claim 4, wherein the first to third color filters have the same shape as the first to third pixel electrodes and each of the first to third color filters is less than each of the first to third sub-pixel electrodes.

6. The electrophoretic display device of claim 5, wherein the first to fourth sub-pixel areas have the same size and shape.

7. The electrophoretic display device of claim 6, wherein the first to fourth sub-pixel areas are formed in a tetragonal shape.

8. The electrophoretic display device of claim 4, wherein the first to third sub-pixel areas have the same shape.

9. The electrophoretic display device of claim 8, wherein the first to third sub-pixel areas surround the fourth sub-pixel area.

10. The electrophoretic display device of claim 9, wherein the first to third sub-pixel areas are formed in a pentagon shape and the fourth sub-pixel electrode is formed in a triangular shape.

11. The electrophoretic display device of claim 9, wherein the first to third sub-pixel areas are formed in a structure in which two hexagons are abutted to each other and the fourth sub-pixel electrode is formed in a hexagonal shape.

12. The electrophoretic display device of claim 2, wherein the first substrate comprises first to fifth sub-pixel areas for displaying red, green, blue, and white.

13. The electrophoretic display device of claim 12, wherein at least two sub-pixel areas of the first to fifth sub-pixel areas display a same color.

14. The electrophoretic display device of claim 13, wherein first to fifth pixel electrodes are formed in the first to fifth sub-pixel areas and have the same shape as the first to fifth sub-pixel areas.

15. The electrophoretic display device of claim 14, wherein the first to fourth sub-pixel areas have the same size and the same shape, and the fifth sub-pixel is of lesser area than each of the first to third sub-pixel areas.

16. The electrophoretic display device of claim 15, wherein the first to third color filters have the same shape as the first to fourth pixel areas and each of the first to third color filters is less than each of the first to fourth sub-pixel electrodes.

17. The electrophoretic display device of claim 16, wherein the first to fourth sub-pixel areas surround the fifth sub-pixel area.

18. The electrophoretic display device of claim 17, wherein the first to fourth sub-pixel areas are formed in a pentagonal shape and the fifth pixel electrode is formed in a tetragonal shape.

19. The electrophoretic display device of claim 1, wherein said plurality of differently colored sub-color filters occupy about 50 percent to about 65 percent of area consumed by said plurality of sub-pixel areas.

20. An electrophoretic display having plural pixel areas whose light reflecting and/or light absorbing states are selectively controlled by plural sub-pixels disposed in each of the pixel areas, where each pixel area is characterized by:

having at least first, second, and third independently controlled sub-pixel areas that respectively comprise first, second, and third color filters of respective first, second, and third different colors for thereby respectively controlling luminance of colored lights therefrom, the first, second, and third sub-pixel areas having a first sub-pixel electrode, a second sub-pixel electrode, and a third sub-pixel electrode associated therewith, respectively, wherein the shape of the first sub-pixel electrode is the same as the shape of the first sub-pixel area in a top view of the electrophoretic display;

having at least one independently controlled, fourth sub-pixel area that does not comprise a color filter, the fourth sub-pixel area also having a sub-pixel electrode associated therewith;

wherein said first, second, and third color filters are spaced apart from one another so as to thereby avoid or reduce a color mixture effect that may arise from mass production misalignment of the first, second, and third color filters relative to the first, second, and third sub-pixel electrodes; and

wherein each of said first, second, and third color filters is smaller in area than its associated sub-pixel electrode so as to thereby avoid or reduce said color mixture effect.