Display device, electronic paper and electronic paper file

• US 20020054033A1
• Filed: 07/17/2001
• Published: 05/09/2002
• Est. Priority Date: 07/18/2000
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nakamura, Tetsuro, Tatekawa, Masichiro
• Granted Patent: US 7,023,418 B2
• Time in Patent Office: Days
• US Class Current: 345/204
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: G02F 1/133616 Front illuminating devices
• CPC Class Codes: G02F 1/13456 Cell terminals located on one side of the display only
• CPC Class Codes: G02F 1/13473 for wavelength filtering or for colour display without the use of colour mosaic filters
• CPC Class Codes: G02F 1/13718 based on a change of the texture state of a cholesteric liquid crystal
• CPC Class Codes: G02F 2203/02 reflective
• CPC Class Codes: G06F 3/14 Digital output to display device ; Cooperation and interconnection of the display device with other functional units
• CPC Class Codes: Y10S 345/901 Electronic book with display

Abstract

The invention comprises a display sheet, a light guide sheet and a light source provided to at least one side of the light guide sheet. And an electronic paper of the invention has a configuration for color display that the display sheet is made up by laminating respective display sheets for red, green and blue colors.

Claims

1. A display device which comprising:

a display sheet;

a light guide sheet joined to a surface of the display sheet; and

a light source placed on at least one side of the light guide sheet.

2. A display device according to claim 1, wherein the light guide sheet is provided with a specific number of grooves to have a specific shape and a specific depth on a surface opposite to the surface of the light guide sheet joined to the display sheet in parallel with the light source at a specific pitch.

3. A display device according to claim 2, wherein the pitch of the grooves is corresponding to a pixel of the display sheet.

4. A display device according to claim 2, wherein the pitch of the grooves gets smaller gradually as the groove keeps away from the light source.

5. A display device according to claim 4, wherein the pitch of the grooves is proportioned to the a-th power of the distance from the light source (a is a constant from −

0.5 to −

3).

6. A display device according to claim 2, wherein the depth of the groove gets larger gradually as the groove keeps away from the light source.

7. A display device according to claim 6, wherein the depth of the groove is proportioned to the h-th power of the distance from the light source (b is a constant from 0.5 to 3).

8. A display device according to either one of claim 3 to 7, wherein the thickness of the light guide sheet is from not less than 0.1 mm to not more than 2 mm, the depth of the groove is from not less than one fifth to not more than one third of the light guide sheet'"'"'s thickness, and a tip angle of the groove is from not less than 60 degrees to not more than 100 degrees.

10. An electronic paper according to claim 1, wherein the display sheet has a reflective type structure that a display sheet using a nonvolatile and reflective liquid crystal for red color, a display sheet using a nonvolatile and reflective liquid crystal for green color, and a display sheet using a nonvolatile and reflective liquid crystal for blue color are laminated.

11. An electronic paper according to claim 1, wherein the light guide sheet is provided with a specific number of grooves to have a specific shape and a specific depth on a surface opposite to the surface of the light guide sheet joined to the display sheet in parallel with the light source at a specific pitch.

12. An electronic paper according to claim 11, wherein the pitch of the grooves is corresponding to a pixel of the display sheet.

13. An electronic paper according to claim 11, wherein the pitch of the grooves is proportioned to the a-th power of the distance from the light source (a:

a constant from −

0.5 to <

3).

14. An electronic paper according to claim 11, wherein the depth of the groove is proportioned to the h-th power of the distance from the light source (h:

a constant from 0.5 to

     3).

15. An electronic paper according to either one of claim 12 to 14, wherein the thickness of the light guide sheet is from not less than 0.1 mm to not more than 2 mm, the depth of the groove is from not less than one fifth to not more than one third of the light guide sheet'"'"'s thickness, and a tip angle of the groove is from not less than 60 degrees to not more than 100 degrees.

16. An electronic paper according to claim 1, wherein an organic or inorganic electro luminescence or a light emitting device is used as the light source.

9. An electronic paper which comprising:

a display sheet using a nonvolatile and reflective liquid crystal;

a light guide sheet joined to a surface of the display sheet; and

a light source placed on at least one side of the light guide sheet.

17. An electronic paper file comprising an electronic paper and control means,

wherein the electronic paper comprises:

a display sheet using a nonvolatile and reflective liquid crystal;

a light guide sheet joined to a surface of the display sheet; and

a light source placed on at least one side of the light guide sheet,

and wherein the control means comprises;

signal sending-receiving means; and

display light emitting control means for sending the display data from the signal sending-receiving means to the electronic paper.