Electrophoretic displays in portable devices and systems for addressing such displays

• US 6,753,999 B2
• Filed: 05/31/2002
• Issued: 06/22/2004
• Est. Priority Date: 03/18/1998
• Status: Expired due to Term

• Current Assignee: E Ink Corporation (E Ink Holdings Incorporated)
• Original Assignee: E Ink Corporation (E Ink Holdings Incorporated)
• Inventors: Zehner, Robert W., Paolini, Richard J. Jr., Duthaler, Gregg M., Morrison, Ian
• Primary Examiner(s): Ben, Loha
• Application Number:
  US10/160,131
• Publication Number:
  US 20030011868A1
• Time in Patent Office: 753 Days
• Field of Search: 359/296, 345/105, 345/107, 345/108, 430/35, 204/450, 204/600, 204/606
• US Class Current: 359/296
• CPC Class Codes: B41J 3/4076 printing on rewritable, bistable "electronic paper" by a focused electric or magnetic field
• CPC Class Codes: B42D 25/29 Securities; Bank notes
• 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 1/1343 Electrodes reflective electrodes G02F1/133553
• CPC Class Codes: G02F 1/1345 Conductors connecting electrodes to cell terminals
• CPC Class Codes: G02F 1/135 Liquid crystal cells structurally associated with a photoconducting or a ferro-electric layer, the properties of which can be optically or electrically varied G02F1/133348 takes precedence
• CPC Class Codes: G02F 1/167 by electrophoresis
• CPC Class Codes: G02F 1/1677 Structural association of cells with optical devices, e.g. reflectors or illuminating devices
• CPC Class Codes: G02F 2202/12 photoconductor
• CPC Class Codes: G02F 2202/28 Adhesive materials or arrangements
• CPC Class Codes: G06K 19/07703 the interface being visual
• CPC Class Codes: G06K 19/14 the marking being sensed by radiation
• CPC Class Codes: G06Q 20/363 with the personal data of a user
• CPC Class Codes: G09F 3/00 Labels, tag tickets, or similar identification or indication means medals or badges A44C3/00; making labels B31D1/02; sheets temporarily attached together B42F; labelling B65C; labels on record carriers G11B23/38, G11B23/40; Seals; Postage or like stamps
• 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: H10K 10/462 Insulated gate field-effect transistors [IGFETs]
• 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 card may include a photoconductive layer and an electrophoretic layer. The impedance of the photoconductive layer is lowered when struck by light from the light-emitting layer. Where the impedance of the photoconductive layer is lowered, the electrophoretic layer may be addressed by an applied electric field to update an image on the card. The image on a card may be updated by a system of updating an image on a card and a method of updating an image on a card that are presented.

Claims

1. A system of updating an image on a card, the system comprising:

(a) a light system generating a pattern of light; and

(b) a card comprising an electrophoretic layer and a photoconductive layer, the photoconductive layer adjacent the electrophoretic layer;

wherein the pattern of light generated by the light system reduces the impedance of the photoconductive layer, permitting an applied electric field to address the electrophoretic layer where the impedance is reduced.

2. The system of claim 1, wherein the light system comprises a light source.

3. The system of claim 1, wherein the light system comprises an emissive display.

4. The system of claim 1, wherein the photoconductive layer is adjacent a first electrode.

5. The system of claim 1, further comprising a first electrode adjacent a first side of the photoconductive layer and a second electrode adjacent the electrophoretic layer.

6. The system of claim 5, wherein the first electrode is clear.

7. The system of claim 6, wherein the first electrode comprises indium tin oxide.

8. The system of claim 5, wherein the second electrode is clear.

9. The system of claim 8, wherein the second electrode comprises indium tin oxide.

10. The system of claim 1, wherein the card further comprises an optical barrier layer between a second side of the photoconductive layer and the electrophoretic layer.

11. The system of claim 1, wherein the card further comprises an optical barrier layer between a first side of the photoconductive layer and a first electrode.

12. The system of claim 1, wherein the card comprises a smart card.

13. The system of claim 12, wherein the smart card further comprises a smart card interface.

14. The system of claim 13, wherein the smart card interface electrically addresses the electrophoretic layer.

15. The system of claim 1, wherein the card further comprises an electrophoretic interface.

16. The system of claim 1, wherein the pattern of light comprises a flood exposure.

17. The system of claim 1, wherein the pattern of light comprises a bar code.

18. The system of claim 1, wherein the photoconductive layer comprises material selected from the group consisting of organic photoconductive polymers, inorganic photoconductors, dye-aggregate photoreceptors, and pigment-based photoconductors.

19. The system of claim 1, wherein the photoconductive layer comprises 2,4,7-trinitro-9-fluorenone complexed with poly(N-vinylcarbazole).

20. A card comprising:

a photoconductive layer; and

an electrophoretic layer, the photoconductive layer adjacent the electrophoretic layer;

wherein the photoconductive layer impedance is reduced when the photoconductive layer is exposed to a pattern of light, permitting an applied electric field to address the electrophoretic layer where the impedance is reduced.

21. The card of claim 20, wherein a first electrode is adjacent a first side of the photconductive layer and a second electrode is adjacent the electrophoretic layer.

22. The card of claim 21, wherein the first electrode is clear.

23. The card of claim 22, wherein the first electrode comprises indium tin oxide.

24. The card of claim 21, wherein the second electrode is clear.

25. The card of claim 24, wherein the second electrode comprises indium tin oxide.

26. The card of claim 20, wherein the card further comprises an optical barrier layer between a second side of the photoconductive layer and the electrophoretic layer.

27. The card of claim 20, wherein the card further comprises an optical barrier layer between a first side of the photoconductive layer and a first electrode.

28. The card of claim 20, wherein the card comprises a smart card.

29. The card of claim 28, wherein the smart card further comprises a smart card interface.

30. The card of claim 20, wherein the card further comprises an electrophoretic layer interface.

31. The card of claim 30, wherein the electrophoretic layer interface further comprises a smart card interface.

32. The card of claim 30, wherein the electrophoretic layer interface comprises a first pad and a second pad, the first pad being electrically coupled to a first electrode and the second pad being electrically coupled to a second electrode.

33. The card of claim 20, wherein the photoconductive layer comprises material selected from the group consisting of organic photoconductive polymers, inorganic photoconductors, dye-aggregate photoreceptors, and pigment-based photoconductors.

34. The card of claim 20, wherein the photoconductive layer comprises 2,4,7-trinitro-9-fluorenone complexed with poly(N-vinylcarbazole).

35. A method of updating an image on a card, the method comprising the steps of:

(a) providing a card comprising an electrophoretic layer and a photoconductive layer, the photoconductive layer adjacent the electrophoretic layer, the photoconductive layer providing impedance;

(b) lowering the impedance of the photoconductive layer by exposing the photoconductive layer to a pattern of light;

(c) addressing the electrophoretic layer by applying an electric field, the image of the card changing in response to the applied electric field and the lowered impedance of the photoconductive layer.

36. The method of claim 35, wherein the pattern of light comprises a flood exposure.

37. The method of claim 35, wherein the pattern of light comprises a bar code.

38. The method of claim 35, further comprising providing a card with a smart card interface.

39. The method of claim 38, wherein the light system comprises a smart card reader.

40. The method of claim 35, further comprising providing a card with an electrophoretic layer interface.

41. The method of claim 40, wherein the electrophoretic layer interface further comprises a smart card interface.