Full color reflective display with multichromatic sub-pixels

• US 6,864,875 B2
• Filed: 05/13/2002
• Issued: 03/08/2005
• Est. Priority Date: 04/10/1998
• Status: Expired due to Term

• Current Assignee: E Ink Corporation (E Ink Holdings Incorporated)
• Original Assignee: E Ink Corporation (E Ink Holdings Incorporated)
• Inventors: Wilcox, Russell J., Drzaic, Paul
• Primary Examiner(s): Nguyen, Jimmy H.
• Application Number:
  US10/145,861
• Publication Number:
  US 20020180688A1
• Time in Patent Office: 1,030 Days
• Field of Search: 345/107, 345/55, 359/296, 349/86, 349/88
• US Class Current: 345/107
• CPC Class Codes: B41J 3/4076 printing on rewritable, bistable "electronic paper" by a focused electric or magnetic field
• CPC Class Codes: G02B 26/026 based on the rotation of particles under the influence of an external field, e.g. gyricons, twisting ball displays based on orientable dipolar particles G02F1/172; based on electrophoresis G02F1/167
• CPC Class Codes: G02F 1/133305 Flexible substrates, e.g. plastics, organic film
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 2001/1678 characterised by the composition or particle type
• CPC Class Codes: G02F 2202/28 Adhesive materials or arrangements
• CPC Class Codes: G09F 9/302 characterised by the form or geometrical disposition of the individual elements
• CPC Class Codes: G09F 9/372 the positions of the elements being controlled by the application of an electric field
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• 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
• CPC Class Codes: H10K 10/462 Insulated gate field-effect transistors [IGFETs]
• CPC Class Codes: H10K 19/00 Integrated devices, or assemblies of multiple devices, comprising at least one organic element specially adapted for rectifying, amplifying, oscillating or switching, covered by group H10K10/00
• CPC Class Codes: H10K 85/30 Coordination compounds
• CPC Class Codes: H10K 85/60 Organic compounds having low molecular weight H10K85/10 - H10K85/50 take precedence

Abstract

A full color, reflective display having superior saturation and brightness is achieved with a novel display element comprising multichromatic elements. In one embodiment a capsule includes more than three species of particles which differ visually. One embodiment of the display employs three sub-pixels, each sub-pixel comprising a capsule including three species of particles which differ visually. Another embodiment of the display employs color filters to provide different visual states to the user. The display element presents a visual display in response to the application of an electrical signal to at least one of the capsules.

Claims

1. A multichromatic electrophoretic display element comprising:

a first capsule comprising a first white particle and a red particle;

a second capsule comprising a second white particle and a green particle;

a third capsule comprising a third white particle and a blue particle; and

three filters each adjacent to one of the capsules, wherein the particles in the three capsules move to present the multichromatic display in response to an applied electrical field, and wherein a white visual appearance of the display is provided by at least one of the white particles.

2. The electrophoretic display element of claim 1, wherein the filters are each of a color selected from the group consisting of white, black, red, green, blue, cyan, magenta, and yellow.

3. The electrophoretic display element of claim 1 wherein at least one of the filters is formed by inkjet printing.

4. The electrophoretic display element of claim 1 wherein at least one of the capsules further includes a suspending fluid.

5. The electrophoretic display element of claim 4 wherein the suspending fluid is substantially clear.

6. A display apparatus comprising:

the display element of claim 1; and

at least one electrode adjacent to the display element.

7. The display apparatus according to claim 6 further comprising a plurality of electrodes adjacent to the display element.

8. The display apparatus according to claim 7 wherein at least one of the plurality of electrodes has a size different from others of the plurality of electrodes.

9. The display apparatus according to claim 7 wherein at least two electrodes differ from each other in an optical property.

10. A multichromatic electrophoretic display element comprising:

a first capsule comprising a first white particle and a cyan particle;

a second capsule comprising a second white particle and a magenta particle;

a third capsule comprising a third white particle and a yellow particle; and

three filters each adjacent to one of the capsules, wherein the particles in the three capsules move to present the multichromatic display in response to an applied electrical field, and wherein a white visual appearance of the display is provided by at least one of the white particles.

11. The electrophoretic display element of claim 10 wherein at least one of the filters is formed by inkjet printing.

12. The electrophoretic display element of claim 10 wherein at least one of the capsules further includes a suspending fluid.

13. The electrophoretic display element of claim 12 wherein the suspending fluid is substantially clear.

14. A display apparatus comprising:

the display element of claim 10; and

at least one electrode adjacent to the display element.

15. The display apparatus according to claim 14 further comprising a plurality of electrodes adjacent to the display element.

16. The display apparatus according to claim 15 wherein at least one of the plurality of electrodes has a size different from others of the plurality of electrodes.

17. The display apparatus according to claim 15 wherein at least two electrodes differ from each other in an optical property.

18. A method of manufacturing a multichromatic electrophoretic display element, comprising the steps of:

providing a first capsule comprising a first white particle and a red particle;

printing a first filter adjacent to the first capsule;

providing a second capsule comprising a second white particle and a green particle;

printing a second filter adjacent to the second capsule;

providing a third capsule comprising a third white particle and a blue particle; and

printing a third filter adjacent to the third capsule, such that when an electric signal is applied to at least one of the capsules, the element is capable of presenting a multichromatic visual display in response to the signal, and such that when a white visual display is presented, it is provided by at least one of the white particles.

19. The method according to claim 18 wherein at least one of the steps of printing comprises inkjet printing.

20. A method of manufacturing a multichromatic electrophoretic display element, comprising the steps of:

providing a first capsule comprising a first white particle and a cyan particle;

printing a first filter adjacent to the first capsule;

providing a second capsule comprising a second white particle and a magenta particle;

printing a second filter adjacent to the second capsule;

providing a third capsule comprising a third white particle and a yellow particle; and

printing a third filter adjacent to the third capsule, such that when an electric signal is applied to at least one of the capsules, the element is capable of presenting a multichromatic visual display in response to the signal, and such that when a white visual display is presented, it is provided by at least one of the white particles.

21. The method according to claim 20 wherein at least one of the steps of printing comprises inkjet printing.