Electrophoretic display device and method for driving the same

• US 7,782,292 B2
• Filed: 03/27/2006
• Issued: 08/24/2010
• Est. Priority Date: 03/29/2005
• Status: Active Grant

• Current Assignee: E Ink Corporation (E Ink Holdings Incorporated)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Miyasaka, Mitsutoshi, Komatsu, Yuko
• Primary Examiner(s): LEWIS, DAVID LEE
• Application Number:
  US11/390,486
• Publication Number:
  US 20060221049A1
• Time in Patent Office: 1,611 Days
• Field of Search: 345/107
• US Class Current: 345/107
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0443 with several sub-pixels for the same colour in a pixel, not specifically used to display gradations G09G3/364 takes precedence
• CPC Class Codes: G09G 2310/0275 Details of drivers for data electrodes, other than drivers for liquid crystal, plasma or OLED displays, not related to handling digital grey scale data or to communication of data to the pixels by means of a current
• CPC Class Codes: G09G 2320/0257 Reduction of after-image effects
• CPC Class Codes: G09G 3/2074 using sub-pixels
• 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

In an electrophoretic display device sandwiching an electrophoretic material between a first substrate and a second substrate, a plurality of pixels are formed on the first substrate; each pixel is composed of n subpixels (n being an integer of 2 or more); and the n subpixels contain at least one pair of adjoining subpixels that cannot be divided by a straight line.

Claims

1. An electrophoretic display device sandwiching an electrophoretic material between a first substrate and a second substrate, the device comprising:

a plurality of pixels being formed on the first substrate,

each of the pixels being composed of n subpixels (n being an integer of 2 or more), the n subpixels having substantially the same area,

wherein the n subpixels contain at least one pair of adjoining subpixels that are not able to be completely divided by a single straight line extending continuously across the pixel.

2. The electrophoretic display device according to claim 1,

wherein the n subpixels contain at least one pair of adjoining subpixels whose boundary side is composed of a plurality of straight lines that extend at angles relative to one another.

3. The electrophoretic display device according to claim 1,

wherein each of the pixels is composed of n subpixels (n being an integer of 3 or more), and

wherein the n subpixels contain at least one pair of adjoining subpixels whose boundary side is longer than a boundary side of another pair of adjoining subpixels.

4. The electrophoretic display device according to claim 1,

wherein at least one subpixel out of the n subpixels does not share a boundary with an adjacent pixel.

5. The electrophoretic display device according to claim 1, wherein a gap between the adjoining subpixels is 10 μ

m or less.

6. The electrophoretic display device according to claim 1, wherein a gap between the adjoining subpixels is shorter than a length expressed by √

(S/n) where S is an area of the pixel.

7. The electrophoretic display device according to claim 1, wherein the n subpixels contain at least one pair of adjoining subpixels whose boundary side is longer than √

S where S is the area of the pixel.

8. The electrophoretic display device according to claim 1, comprising a subpixel selection unit that selects i subpixels (i being an integer between 1 and n) from the n subpixels when displaying a brightness gray-scale i so that a boundary side separating a dark display subpixel from a bright display subpixel is longest, provided that a state in which all the n subpixels perform the dark display is a brightness gray-scale 0 and that a state in which the i subpixels perform the bright display and in which n−

i subpixels perform the dark display is the brightness gray-scale i.

9. The electrophoretic display device according to claim 1, further comprising a subpixel selection unit which makes the i subpixels (i being an integer between 1 and n) located closer to a center of the pixel to perform a bright display by selecting the i subpixels from the n subpixels when displaying a brightness gray-scale i, provided that a state in which all the n subpixels perform the dark display is a brightness gray-scale 0 and that a state in which the i subpixels perform the bright display and in which n−

i subpixels perform the dark display is the brightness gray-scale i.

10. The electrophoretic display device according to claim 1, further comprising a subpixel selection unit which makes the i subpixels (i being an integer between 1 and n) located farther from a center of the pixel to perform a bright display by selecting the i subpixels from the n subpixels when displaying a brightness gray-scale i, provided that a state in which all the n subpixels perform the dark display is a brightness gray-scale 0 and that a state in which the i subpixels perform the bright display and in which n−

i subpixels perform the dark display is the brightness gray-scale i.

11. The electrophoretic display device according to claim 1, further comprising a subpixel selection unit which selects i subpixels (i being an integer between 1 and n) from the n subpixels as a bright display when displaying a brightness gray-scale i so that the display having a smaller area is located more towards an inside than the display having a larger area upon comparison of a total area of the dark display subpixels with a total area of the bright display subpixels, provided that a state in which all the n subpixels perform the dark display is a brightness gray-scale 0 and that a state in which the i subpixels perform the bright display and in which n−

i subpixels perform the dark display is the brightness gray-scale i.

12. The electrophoretic display device according to claim 1, further comprising a subpixel selection unit which selects i subpixels (i being an integer between 1 and n) from the n subpixels as a bright display when displaying a brightness gray-scale i so that the display having a smaller area is located more towards an outside than the display having a larger area upon comparison of a total area of the dark display subpixels with a total area of the bright display subpixels, provided that a state in which all the n subpixels perform the dark display is a brightness gray-scale 0 and that a state in which the i subpixels perform the bright display and in which n−

i subpixels perform the dark display is the brightness gray-scale i.

13. A method for driving an electrophoretic display device according to claim 1, the method comprising:

selecting i subpixels (i being an integer between 1 and n) from the n subpixels as a bright display so that a boundary side separating a dark display subpixel from a bright display subpixel becomes longest when displaying a brightness gray-scale i, provided that a state in which all the n subpixels perform the dark display is a brightness gray-scale 0 and that a state in which the i subpixels perform the bright display and in which n−

i subpixels perform the dark display is the brightness gray-scale i.

14. A method for driving an electrophoretic display device according to claim 1, the method comprising:

selecting i subpixels (i being an integer between 1 and n) from the n subpixels as a bright display when displaying a brightness gray-scale i so that the display having a smaller area is located more towards an inside than the display having a larger area upon comparison of a total area of the dark display subpixels with a total area of the bright display subpixels, provided that a state in which all the n subpixels perform the dark display is a brightness gray-scale 0 and that a state in which the i subpixels perform the bright display and in which n−

i subpixels perform the dark display is the brightness gray-scale i.

15. A method for driving an electrophoretic display device according to claim 1, the method comprising:

selecting i subpixels (i being an integer between 1 and n) from the n subpixels as a bright display when displaying a brightness gray-scale i so that the display having a smaller area is located more towards an outside than the display having a larger area upon comparison of a total area of the dark display subpixels with a total area of the bright display subpixels, provided that a state in which all the n subpixels perform the dark display is a brightness gray-scale 0 and that a state in which the i subpixels perform the bright display and in which n−

i subpixels perform the dark display is the brightness gray-scale i.