Electrically erasable writing surface

• US 20030156099A1
• Filed: 02/19/2002
• Published: 08/21/2003
• Est. Priority Date: 02/19/2002
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: Yrjanainen, Yukka, Kangas, Jari A., Hautanen, Jukka
• Granted Patent: US 7,136,048 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0488 using a touch-screen or digitiser, e.g. input of commands through traced gestures

Abstract

An electrically erasable writing surface is provided. The writing surface includes a bistable display layer that responds to electrical and mechanical inputs. A touch pad is located above or below the display layer. The writing surface facilitates writing complex characters and increases accuracy by displaying a user input created by a passive stylus.

Claims

1. A writing surface, the writing surface comprising:

a display layer comprising electrically and mechanically sensitive display material having at least two stable optical states;

a touch pad physically coupled to the display layer, the touch pad configured to convert a mechanical input into an electrical output.

2. The writing surface device of claim 1, wherein the display material comprises liquid crystal material.

3. The writing surface of claim 2, wherein the liquid crystal material comprises cholesteric liquid crystal material.

4. The writing surface of claim 2, wherein the liquid crystal material comprises twisted nematic liquid crystal material.

5. The writing surface of claim 2, wherein the display layer comprises polymer dispersed throughout the liquid crystal material.

6. The writing surface of claim 1, further including a flexible substrate located above the display layer.

7. The writing surface of claim 6, further including a transparent electrode located between the flexible substrate and a first side of the display layer.

8. The writing surface of claim 7, further including a reflective layer located below a second side of the display layer.

9. The writing surface of claim 8, wherein the reflective layer comprises an electrode.

10. The writing surface of claim 1, wherein the display material comprises a suspended particle material.

11. The writing surface of claim 1, further including a driver module coupled to the display layer and configured to apply a field to reset the state of the display material.

12. The writing surface of claim 11, wherein the field comprises an electric field.

13. The writing surface of claim 11, wherein the field comprises a magnetic field.

14. The writing surface of claim 1, wherein the display layer is positioned in an overlapping relationship with the touch pad.

15. The writing surface of claim 1, further including an output display electrically coupled to the touch pad.

16. The writing surface of claim 15, wherein the output display comprises the display material.

17. A pressure sensitive input device comprising the writing surface of claim 1.

18. The pressure sensitive input device of claim 17, further including a keypad.

19. A user interface for use with an electronic device, the user interface comprising:

an optical output section; and

a mechanical input section comprising;

a display layer comprising electrically and mechanically sensitive display material having at least two stable optical states; and

a touch pad physically coupled to the display layer, the touch pad configured to convert a mechanical input into an electrical output.

20. The user interface of claim 19, further comprising:

a key pad section comprising pressure sensitive keys.

21. The user interface of claim 19, wherein the optical output section comprises a display electrically coupled to the touch pad.

22. A mobile terminal comprising:

an output display; and

a mechanical input device comprising;

a display layer comprising electrically and mechanically sensitive display material having at least two stable optical states; and

a touch pad physically coupled to the display layer, the touch pad configured to convert a mechanical input into an electrical output.

23. The mobile terminal of claim 22, wherein the output display is integrated with the mechanical input device.

24. The mobile terminal of claim 23, wherein the output display comprises at least a portion of the display layer.

25. The mobile terminal of claim 22, wherein the display material comprises liquid crystal material.

26. The mobile terminal of claim 25, wherein the liquid crystal material comprises cholesteric liquid crystal material.

27. The mobile terminal of claim 25, wherein the liquid crystal material comprises twisted nematic liquid crystal material.

28. The mobile terminal of claim 22, further including a character recognition module coupled to the touch pad.

29. A method of operating an input device having an electrically and mechanically sensitive display layer having at least two stable optical states and physically coupled to a touch pad, the method comprising:

(a) receiving at the display layer and the touch pad a mechanical input;

(b) in response to (a) changing an optical state of the display layer;

(c) at the touch pad, in response to (a), converting the physical input to an electrical output.

30. The method of claim 29, further including:

(d) applying a field to the display layer to reset the state of the display layer.

31. The method of claim 29, further including:

(d) transmitting the electrical output to a character recognition module;

(e) generating a character at the character recognition module; and

(f) in response to the character generated in (e) transmitting an electrical signal to an output display.