Ferroelectric liquid crystal data storage card

• US 4,954,985 A
• Filed: 05/09/1988
• Issued: 09/04/1990
• Est. Priority Date: 05/09/1987
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Moffit, James W.
• Application Number:
  US07/192,016
• Time in Patent Office: 848 Days
• Field of Search: 365/108, 365/109, 365/117, 365/145, 365/180, 235/380, 235/487, 235/492
• US Class Current: 365/108
• CPC Class Codes: G02F 1/141 using ferroelectric liquid crystals
• CPC Class Codes: G06K 19/06009 with optically detectable marking G06K19/063, G06K19/08 take precedence
• CPC Class Codes: G06K 19/077 Constructional details, e.g. mounting of circuits in the carrier
• CPC Class Codes: G06K 19/07703 the interface being visual
• CPC Class Codes: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G07F 7/0866 by active credit-cards adapted therefor G07F7/1008 takes precedence

Abstract

A card with a display function and a data storage capability comprises a pair of substrates; a plurality of electrodes on the substrates; a liquid crystal orientation control film on the electrodes; and a liquid crystal material with a strong dielectric property filled between the pair of substrates; wherein the liquid crystal material with the strong dielectric property is utilized to provide for a liquid crystal display region and a data storage region to write in, erase, and rewrite external data by addition of external energy to the liquid crystal material.

Claims

1. A non-volatile ferroelectric crystal card memory comprising:

a pair of card substrates, at least one of said substrates being transparent;

a first ferroelectric liquid crystal layer disposed between said substrates;

an electrode arrangement provided on the inside surfaces of said pair of substrates for applying an electric field to change the anisotropic direction of said liquid crystal layer, wherein said electrode arrangement is a pair of electrodes extending opposite to each other with said liquid crystal layer inbetween;

a pair of orientation control films provided on the opposed insides of said substrates;

a display section which is composed of a second ferroelectric liquid crystal layer between said pair of card substrates whose optical property is controlled by applying an electric field thereto; and

a second electrode arrangement provided on the inside surfaces of said pair of substrates for applying a particular portion of said second liquid crystal layer to display visual information.

2. A card memory comprising;

a pair of substrates, at least one of said substrates being transparent;

a first ferroelectric liquid crystal material disposed between said substrates;

first and second electrode arrangements formed on the inside surfaces of said substrates in order to form a memory section in which information can be stored in terms of the bistability of said liquid crystal material and a display section in which visual information can be displayed in terms of the bistability of said liquid crystal material; and

a pair of orientation control films provided on the opposed insides of said substrates.

3. The card memory of claim 2, wherein said visual information is letters, characters, symbols, or other images.

4. The memory of claim 3, wherein said second electrode arrangement is formed into a matrix structure.

5. The memory of claim 3, wherein said liquid crystal material in said memory and display sections are made of a same ferroelectric liquid crystal material.

6. The memory of claim 5, further comprising an IC chip for driving said memory section and said display section.

7. The memory of claim 6, further comprising an external terminal for receiving a control signal from an external device.

8. The memory of claim 6, further comprising an external terminal for receiving electric power required for operation of said memory.

9. The memory of claim 6, further comprising a solar cell for supplying electricity to said memory.

10. The memory of claim 2, wherein each of said substrates is 8.6 cm wide and 5.4 cm long.

11. A card memory comprising:

a pair of substrates wherein at least a portion of one of said substrates is transparent;

a ferroelectric liquid crystal layer interposed between said substrates, said ferroelectric liquid crystal layer comprising a first portion and a second portion, said first portion being located to receive light rays through the transparent portion of at least one of said substrates;

a first electrode arrangement formed on the inside surfaces of said pair of substrates and located on both sides of the first portion of said liquid crystal layer in order to constitute a liquid crystal display by said first electrode arrangement and said first portion of said ferroelectric liquid crystal layer; and

a second electrode arrangement formed on the inside surfaces of said pair of substrates and located on both sides of said second portion of said liquid crystal layer in order to constitute a non-volatile liquid crystal memory by said second electrode arrangement and said second portion of said ferroelectric liquid crystal layer, wherein information is stored in terms of the bistability of said liquid crystal layer.

12. The memory of claim 11, wherein said information is letters, characters, symbols, or other images.

13. The memory of claim 12, wherein said second electrode arrangement is formed into a matrix structure.

14. The memory of claim 12, wherein said first and second liquid crystal layers are made of a same ferrolectric liquid crystal material.

15. The memory of claim 14 further comprising an IC chip for driving said memory and said display.

16. The memory of claim 15 further comprising an external terminal for receiving control signal from an external device.

17. The memory of claim 15 further comprising an external terminal for receiving electric power required for operation of said memory.

18. The memory of claim 15 further comprising a solar cell for supplying an electricity to said memory.

19. The memory of claim 11 further comprising a pair of orientation control films provided on the opposed insides of said substrates, one film being made of polyimide and the other being made of SiO2.

20. The memory of claim 11, wherein said memory substrate is 8.6 cm wide and 5.4 cm long.