Electronic shelf label

• US 20030053014A1
• Filed: 09/18/2002
• Published: 03/20/2003
• Est. Priority Date: 09/19/2001
• Status: Active Grant

• Current Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Original Assignee: Optrex Corporation (Kyocera Corporation)
• Inventors: Niiyama, Satoshi, Suehiro, Noriko
• Granted Patent: US 6,914,648 B2
• Time in Patent Office: Days
• US Class Current: 349/106
• CPC Class Codes: G02F 1/133397 for suppressing after-image or image-sticking
• CPC Class Codes: G02F 1/13473 for wavelength filtering or for colour display without the use of colour mosaic filters
• CPC Class Codes: G02F 1/13478 based on selective reflection
• CPC Class Codes: G02F 1/13718 based on a change of the texture state of a cholesteric liquid crystal
• CPC Class Codes: G09G 2300/0486 Cholesteric liquid crystals, including chiral-nematic liquid crystals, with transitions between focal conic, planar, and homeotropic states
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 2320/0257 Reduction of after-image effects
• CPC Class Codes: G09G 3/3629 using liquid crystals having memory effects, e.g. ferroelectric liquid crystals

Abstract

There are provided at least two liquid crystal panels 10, 20 including the liquid crystals developing a memory effect, the liquid crystal developing a memory effect on a side opposite to a viewer side has a selective reflection wavelength set at 615-665 nm, the liquid crystal developing a memory effect on the viewer side has a selective reflection wavelength set at 490-540 nm, and a color filter having a certain transmission property is provided between the liquid crystal developing a memory effect on the viewer side and the liquid crystal developing a memory effect on the side opposite to the viewer side.

Claims

1. An electronic shelf label comprising a liquid crystal display element comprised of a liquid crystal layer and at least two electrodes characterized in that at least two chiral nematic liquid crystal layers are arranged, in which each chiral nematic liquid crystal layer is able to develop at least two different stable optical states without applying voltage to said liquid crystal layer, and at least three colors per a pixel or a segment of said liquid crystal display element are obtainable on display.

2. The electronic shelf label according to claim 1 characterized in that at least four colors per a pixel or a segment of said liquid crystal display element are obtainable.

3. The electronic shelf label according to claim 1 characterized in that a white color and a black color are included in said colors.

4. The electronic shelf label according to claim 1 characterized in that a red color and a green color are included in said colors.

5. The electronic shelf label according to claim 1 characterized in that a white color and a blue color are included in said colors.

6. The electronic shelf label according to claim 1 characterized in that a red color and a green color are obtainable in said colors.

7. The electronic shelf label according to claim 1 characterized in that a difference between a center wavelength of a selective reflective color in a planar state of one liquid crystal layer and that of the other liquid crystal layer said is equal to or longer than 50 nm.

8. The electronic shelf label according to claim 1 characterized in that a center wavelength in a planar state of one of said liquid crystal layers is less than 550 nm or equal to 550 nm.

9. The electronic shelf label according to claim 1 characterized in that a color filter is arranged in said liquid crystal display element.

10. The electronic shelf label according to claim 1 characterized in that a layer which is able to absorb a certain wavelength is sandwiched between two chiral nematic liquid crystal layers.

11. The electronic shelf label according to claim 1 characterized in that at least two colors are used for a price information in the same background color.

12. The electronic shelf label according to claim 1 characterized in that a segment type electrode is arranged to show a information.

13. The electronic shelf label according to claim 1 characterized in that a segment type electrode is arranged to show a information and a electrode for a background color is arranged.

14. The electronic shelf label according to claim 1 characterized in that dot-matrix type electrodes are arranged to show a information.

15. The electronic shelf label according to claim 1 characterized in that both a segment type electrode and dot-matrix type electrodes are arranged to show a information.

16. The electronic shelf label according to claim 1 characterized in that a white color is developed by mixing of two colors which are selective reflective color in a planar states of two chiral nematic liquid crystal layers.

17. The electronic shelf label according to claim 1 characterized in that a signal including a information on a display is inputted to liquid crystal display element by a wireless communication device.

18. The electronic shelf label according to claim 17 characterized in that an IR communication technique is used for said wireless communication device.

19. The electronic shelf label according to claim 17 characterized in that a Bluetooth technique is used for said wireless communication device.

20. The electronic shelf label according to claim 1 characterized in that a battery is used for a power supply to drive said chiral nematic liquid crystal layer.