Liquid crystal display device

• US 5,790,215 A
• Filed: 03/13/1996
• Issued: 08/04/1998
• Est. Priority Date: 03/15/1995
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Naito, Katsuyuki, Nakai, Yutaka, Sugahara, Atsushi, Suzuki, Kohei, Kamiura, Norihiko
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): NGUYEN, TIEP HUU
• Application Number:
  US08/614,500
• Time in Patent Office: 874 Days
• Field of Search: 349/74, 349/77, 349/79, 349/86, 349/89, 349/110, 349/111
• US Class Current: 349/74
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
• CPC Class Codes: G02F 1/1347 Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
• CPC Class Codes: G02F 1/13475 in which at least one liquid crystal cell or layer is doped with a pleochroic dye, e.g. GH-LC cell G02F1/13476 takes precedence

Abstract

This invention is a liquid crystal display device including a reflecting plate formed above a substrate, and a liquid crystal cell formed by alternately, repeatedly stacking a liquid crystal layer and a transparent electrode layer at least once on the reflecting plate, wherein the liquid crystal layer includes a thin film constituted by a microcapsulated guest-host liquid crystal containing dye molecules and liquid crystal molecules.

Claims

1. A liquid crystal display device, comprising:

a substrate;

a reflecting plate formed above said substrate; and

a liquid crystal cell including a plurality of liquid crystal layers and a plurality of transparent electrode layers, said liquid crystal layers and said transparent electrode layers being alternately disposed to form a stacking structure above said reflecting plate,

wherein active elements for controlling a potential information given to all the transparent electrode layers are formed on said substrate, and each transparent electrode layer is electrically connected to said active elements.

2. The liquid crystal display device according to claim 1, wherein said liquid crystal layer is formed of guest-host liquid crystal material containing dye molecules and liquid crystal molecules.

3. The liquid crystal display device according to claim 2, wherein said liquid crystal layer is formed of a thin film having said guest-host liquid crystal material microencapsulated therein.

4. The liquid crystal display device according to claim 1, wherein said liquid crystal layer contains a selective reflection mode liquid crystal material.

5. The liquid crystal display device according to claim 1, wherein a stacking structure comprises a first liquid crystal layer, a first transparent electrode layer, a first transparent insulating layer, a second transparent electrode layer, a second liquid crystal layer, a third transparent electrode layer, a second transparent insulating layer, a fourth transparent electrode layer, and a third liquid crystal layer, said first transparent electrode layer being electrically connected to said second transparent electrode layer, and said third transparent electrode layer being electrically connected to said fourth transparent electrode layer.

6. The liquid crystal display device according to claim 1, wherein said reflecting plate further serves as a shield plate and is supplied with a fixed potential from a fixed potential source.

7. The liquid crystal display device according to claim 1, wherein an insulating film is provided between the substrate and the reflecting plate.

8. The liquid crystal display device according to claim 1, wherein the active elements are provided on a portion of the substrate beneath the reflecting plate.

9. A liquid crystal display device comprising:

a substrate;

a reflecting plate formed above said substrate;

a liquid crystal cell formed by stacking at least one liquid crystal layer and at least one transparent electrode layer on said reflecting plate; and

active elements formed on said substrate and electrically connected to the reflecting layer and to the at least one transparent electrode layer for supplying voltage potentials to the reflecting layer and to the at least one transparent electrode layer,

wherein said at least one liquid crystal layer includes a thin film having a microcapsulated guest-host liquid crystal containing dye molecules and liquid crystal molecules.

10. The liquid crystal display device according to claim 9, wherein a plurality of liquid crystal layers and transparent electrode layers are alternately stacked on said reflecting plate.

11. The liquid crystal display device according to claim 9, wherein three transparent electrode layers and three liquid crystal layers are alternately stacked on said reflecting plate, and colors of said liquid crystal layers correspond to cyan, magenta, and yellow.

12. The liquid crystal display device according to claim 11, wherein there are three active elements formed on said substrate and electrically connected to one scanning line.

13. The liquid crystal display device according to claim 9, wherein four transparent electrode layers and four liquid crystal layers are alternately stacked on said reflecting plate, and colors of said liquid crystal layers correspond to cyan, magenta, yellow, and black.

14. The liquid crystal display device according to claim 9, wherein said transparent electrode layer and said active elements are electrically connected by a plating layer.

15. The liquid crystal display device according to claim 9, wherein said reflecting plate is an electrode.

16. The liquid crystal display device according to claim 9, wherein said transparent electrode layer and said active elements are electrically connected by one material selected from the group consisting of a conductive paste, a metal deposition film, a metal sputtering film, a conductive metal oxide deposition film, and a conductive metal oxide sputtering film.

17. The liquid crystal display device according to claim 9, wherein a diameter of microcapsules constituting said liquid crystal layer is not more than a cell gap.

18. The liquid crystal display device according to claim 9, wherein a thickness of said thin film is 5 to 15 μ

m.

19. The liquid crystal display device according to claim 9, wherein said microcapsulated guest-host liquid crystal contains an additional polymer as a microcapsulating agent.

20. The liquid crystal display device according to claim 9, wherein the liquid crystal cell has at least three different color liquid crystal layers having different color dye molecules alternately stacked with at least two transparent electrode layers.

21. The liquid crystal display device according to claim 20, wherein the active elements supply two different alternating voltage potentials to the reflecting plate and the at least two transparent electrode layers to selectively switch the at least three different color liquid crystal layers between a mode causing light transmission through a given liquid crystal layer and a mode causing light absorption by a given liquid crystal layer to control a color being displayed by the liquid crystal display device.

22. The liquid crystal display device according to claim 21, wherein one of the at least three different color liquid crystal layers is cyan colored, one of the at least three different color liquid crystal layers is magenta colored, and one of the at least three different color liquid crystal layers is yellow colored.

23. The liquid crystal display device according to claim 21, wherein the active elements supply different alternating voltage potentials in a range from +V to -V to the reflecting plate and the at least two transparent electrode layers to selectively switch the at least three different color liquid crystal layers between a mode causing light transmission through a given liquid crystal layer and at least two absorption modes causing different degrees of light absorption by a given liquid crystal layer to control a color being displayed by the liquid crystal display device.

24. The liquid crystal display device according to claim 23, wherein one of the at least three different color liquid crystal layers is cyan colored, one of the at least three different color liquid crystal layers is magenta colored, and one of the at least three different color liquid crystal layers is yellow colored.

25. The liquid crystal display device according to claim 9, wherein the reflecting plate is in direct electrical contact with one of the active elements.

26. The liquid crystal display device according to claim 9, wherein the reflecting plate is provided with a roughened surface to provide a predetermined degree of reflective light diffraction.

27. The liquid crystal display device according to claim 9, wherein the at least one liquid crystal layer and the at least one transparent electrode layer are in direct contact.

28. The liquid crystal display device according to claim 9, wherein an insulating film is provided between the substrate and the reflecting plate.

29. The liquid crystal display device according to claim 9, wherein the active elements are provided on a portion of the substrate beneath the reflecting plate.

30. A liquid crystal display device comprising:

a substrate;

a reflecting plate formed above said substrate;

a liquid crystal cell formed by stacking at least one liquid crystal layer and at least one transparent electrode layer on said reflecting plate;

wherein said at least one liquid crystal layer includes a thin film comprised of a microcapsulated guest-host liquid crystal containing dye molecules and liquid crystal molecules; and

a shield electrode formed between said substrate and said reflecting plate, said shield electrode being provided with a fixed potential from a source of fixed potential.

31. The liquid crystal display device according to claim 30, wherein an insulating film is provided between the substrate and the reflecting plate.

32. The liquid crystal display device according to claim 30, wherein active elements are provided on said substrate and electrically connected to the reflecting layer and to the at least one transparent electrode layer.

33. The liquid crystal display device according to claim 32, wherein the active elements are provided on a portion of the substrate beneath the shield electrode formed between the substrate and the reflecting plate.

34. A liquid crystal display device comprising:

a substrate;

a reflecting plate electrode formed above said substrate;

a liquid crystal cell formed by stacking at least one liquid crystal layer and at least one transparent electrode layer on said reflecting plate electrode;

wherein said at least one liquid crystal layer includes a thin film comprised of a microcapsulated guest-host liquid crystal containing dye molecules and liquid crystal molecules; and

wherein said reflecting plate electrode serves as a shield electrode which is provided with a fixed potential from a source of fixed potential.

35. The liquid crystal display device according to claim 34, wherein an insulating film is provided between the substrate and the reflecting plate.

36. The liquid crystal display device according to claim 34, wherein active elements are provided on said substrate and electrically connected to the reflecting layer and to the at least one transparent electrode layer.

37. The liquid crystal display device according to claim 36, wherein the active elements are located on a portion of the substrate beneath the reflecting plate.

38. A method of driving a liquid crystal display device, said device comprising a substrate, a reflecting plate formed above said substrate, a liquid crystal cell including a plurality of liquid crystal layers and a plurality of transparent electrode layers, said liquid crystal layers and said transparent electrode layers being alternately disposed to form a stacked structure above the reflecting plate, and substrate supported active elements mounted below the reflecting plate and electrically connected to the reflecting plate and the transparent electrode layers, comprising the steps of:

applying at least two different alternating voltage levels to said reflecting plate; and

applying said at least two different alternating voltages to said transparent electrode layers,

wherein the order in which the two different voltages are applied to the reflecting electrode and the transparent electrode layers is different to create different display effects.

39. The method according to claim 38, wherein the different display effects result from the steps of applying the at least two different alternating voltages and an associated condition wherein a transmittance or a reflectance of liquid crystal molecules and dye molecules contained in said liquid crystal layers becomes a maximum or a minimum with respect to incident light in a direction substantially perpendicular to a surface of said reflecting plate or of said transparent electrode layers.