Display device

• US 20090141335A1
• Filed: 11/10/2008
• Published: 06/04/2009
• Est. Priority Date: 02/19/2002
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Liquavista B.V. (Amazon.com, Inc.)
• Inventors: Feenstra, Bokke Johannes, Prins, Menno Willem Jose, Hayes, Robert Andrew
• Granted Patent: US 7,898,718 B2
• Time in Patent Office: Days
• US Class Current: 359/290
• CPC Class Codes: G02B 2207/115 Electrowetting
• CPC Class Codes: G02B 26/005 based on electrowetting
• CPC Class Codes: G09F 9/372 the positions of the elements being controlled by the application of an electric field

Abstract

Display device is based on layer break up or layer displacement having at least two different states, in which one of the fluids, e.g., oil in a first state, adjoins at least a first support plate and, in the second state, the other fluid at least partly adjoins the first support plate. In one embodiment, a picture element corresponds to a substantially closed space and, in the first state, the other fluid layer substantially completely adjoins both support plates and is divided in two sub-layers. This makes it possible, on the one hand, to use lower voltages to make displacement occur. On the other hand, this opens the opportunity to color displays.

Claims

1. A display device comprising:

picture elements having at least one first fluid and a second fluid immiscible with each other within a space between a first support plate and a second support plate, the second fluid being electroconductive or polar,

a picture element of the device being electrically switchable between at least a first state without an electric field applied and a second, different state with an electric field applied,

in which in the first state the first fluid is spread out in the picture element and adjoins an area of the first support plate, and

in the second state the second fluid adjoins the said area of the first support plate and the first fluid is contracted at a side of the picture element,

in which said states provide a display effect over the area, and the first fluid is confined to the space of the picture element in the first state and in the second state.

2. A display device according to claim 1, in which the second fluid is confined to the space of the picture element.

3. A display device according to claim 1, in which in the second state the first fluid is absent from a volume between the first support plate and the second support plate bound by the area of the first support plate.

4. A display device according to claim 1, wherein in the first state the second fluid forms a fluid layer on the first fluid, the first fluid being arranged between the second fluid layer and the first support plate.

5. A display device according to claim 4, wherein the first fluid forms a first fluid layer.

6. A display device according to claim 1, in which the second fluid forms a layer common to several picture elements.

7. A display device according to claim 1, the device comprising an inhomogeneous electric field creator for creating within a picture element an inhomogeneous electric field at the surface of a part of the first support plate.

8. A display device according to claim 7, wherein the inhomogeneous electric field is applied for moving the first fluid to the side of the picture element.

9. A display device according to claim 7 or 8, in which a dielectric layer between an electrode and a surface of the part of the first support plate varies in thickness or has a varying dielectric constant.

10. A display device according to claim 7 or 8, in which the surface of a part of the first support plate has a varying wettability or the first fluid layer has a varying thickness.

11. A display device according to claim 7 or 8, including an electrode structure for creating the inhomogeneous electric field.

12. A display device according to claim 7 or 8, including an electrode having edges, a stray field of the edges forming the inhomogeneous electric field.

13. A display device according to claim 1, in which the first fluid adjoins only one of the support plates in the first state and in the second state.

14. A display device according to claim 1, in which a picture element corresponds to a defined space and in the second state the second fluid substantially completely adjoins the first support plate.

15. A display device according to claim 1, in which the picture element corresponds to a defined space including a further first fluid which forms in a further first state a further first fluid layer adjoining the second support plate.

16. A display device according to claim 15 in which the picture element has a wall part dividing the space into at least two sub-picture elements, in the first state the further first fluid layer adjoining the second support plate at least partly within both sub-picture elements.

17. A display device according to claim 15 in which the first fluid layer and the further first fluid layer have different colors.

18. A display device according to claim 15 in which in the second state at least one of the first fluid layer and the further first fluid layer adjoins a wall part of the space.

19. A display device according to claim 1 which comprises an absorber or a reflector configured to absorb or reflect light incident on the display device.

20. A display device according to claim 1 which comprises a reflector configured to reflect light incident on the display device, wherein the reflector is diffusive.

21. A display device according to claim 1, in which the second fluid is a scattering, a reflective or an absorbing fluid.

22. A display device according to claim 1 in which the second fluid is a scattering fluid, wherein the scattering fluid includes TiO₂.

23. A display device according to claim 1 which comprises a color filter.

24. A display device according to claim 1, wherein the fluids include a pigment.

25. A display device according to claim 24, wherein said second fluid includes the pigment.

26. A display device according to claim 1, wherein scattering particles are included in said first fluid and/or said second fluid.

27. A display device according to claim 1, wherein the picture element includes a hydrophobic layer and said area of the first support plate is an area of the hydrophobic layer.

28. A display device according to claim 1, wherein the first fluid adjoins the first support plate in any state of the picture element.

29. A display device according to claim 1, wherein part of the first support plate is adjoined by first fluid in the first state and in the second state.

30. A display device according to claim 1, wherein the picture element is arranged to use electrostatic forces to switch the first fluid between the first state and the second state.

31. A display device according to claim 1, wherein the first fluid is arranged to be displaced by the second fluid in the switching from the first state to the second state.

32. A display device according to claim 1, wherein in the first state the first and second fluids adjoin each other substantially over an extent of the picture element.

33. A display device according to claim 1, including an electrode contacting the second fluid.

34. A display device according to claim 33, wherein said electrode is arranged on the first support plate.

35. A display device according to claim 34, in which the electrode is connected by a through-connection through a layer arranged on the support plate.

36. A display device according to claim 1, wherein an electrode is arranged on the first support plate for creating the electric field between the second fluid and the electrode.

37. A display device according to claim 1, wherein the picture element is partly transparent and partly reflective in one of the states.

38. A display device according to claim 1 having a viewing direction, wherein one of the support plates faces the viewing direction and the first fluid adjoins said support plate.

39. A display device according to claim 1, wherein the second fluid includes ions.

40. A display device according to claim 39, wherein the second fluid is an ionic liquid.