Liquid crystal display device and display apparatus using same

• US 5,194,973 A
• Filed: 11/27/1991
• Issued: 03/16/1993
• Est. Priority Date: 11/29/1990
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Komura, Shinichi, Kondo, Katsumi, Hirakata, Junichi, Kitamura, Teruo, Isogai, Masato
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): MAI, HUY KIM
• Application Number:
  US07/799,275
• Time in Patent Office: 475 Days
• Field of Search: 359/51, 359/52, 359/53, 359/77, 359/93, 359/96, 359/102, 353/35, 353/31
• US Class Current: 349/10
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
• 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

A liquid crystal display device characterized in comprising a set of substrates facing each other at least one of which is transparent, transparent electrodes provided respectively to each facing plane of the substrates, a light absorbing layer held between the transparent electrodes, and an electric power source for applying electric field to the light absorbing layer, and that the light absorbing layer is composed of two layers, each of the layers has dichroism, average light absorbing axis of the each layers without electric field is approximately parallel to the substrate plane and crossing each other almost orthogonally, and the average light absorbing axis of the each layers changes the axis direction by applying of electric field. In accordance with the present invention, the liquid crystal display device having eye-tireless bright display, long life time, and electric power saving character is realized.

Claims

1. A liquid crystal display device characterized in:

comprising;

a set of substrates faced each other at least one of which is transparent,

transparent electrodes provided respectively to each facing plane of said substrates,

a light absorbing layer held between said transparent electrodes, and

an electric power source for applying electric field to said light absorbing layer through said transparent electrodes, and that;

said light absorbing layer is composed of two layers,

each of the layers has dichroism,

average light absorbing axis of the each layers without electric field is approximately parallel to the substrate plane and crossing each other almost orthogonally, and

said average light absorbing axis of the each layers changes the axis direction by applying of electric field.

9. The liquid crystal display device as claimed in any one of claims from 1 to 4, wherein;

said light absorbing layer is transparent polymer matrix in which nematic liquid crystal is dispersed particlewise, and

average particle size of said nematic liquid crystal is at least 1 μ

m.

16. The liquid crystal display device as claimed in any one of claims 1, 2, 4, and 11, wherein;

transistors are formed on one of transparent electrodes formed on said substrates.

17. The liquid crystal display device as claimed in any one of claims 1, 2, 4, and 11, wherein;

a reflector is provided outside of said substrates.

2. A liquid crystal display device characterized in:

comprising;

a set of substrates faced each other at least one of which is transparent,

transparent electrodes provided respectively to each facing plane of said substrates,

a light absorbing layer held between said transparent electrodes, and

an electric power source for applying electric field to said light absorbing layer through said transparent electrodes, and that;

said light absorbing layer is composed of two layers,

each of the layers has dichroism,

average light absorbing axis of the each layers without electric field is approximately parallel to the substrate plane and crossing each other almost orthogonally,

the one of said light absorbing layers is composed of polymer layer and liquid crystal, that is, nematic liquid crystal having dichroism and positive dielectric anisotropy is dispersed in transparent polymer matrix, and

the other light absorbing layer is a nematic liquid crystal layer surrounded with seal members and having dichroism and positive dielectric anisotropy.

3. The liquid crystal display device as claimed in claim 2, wherein;

the contacting portion of said polymer layer with said liquid crystal layer and the portion of said transparent electrode formed plane of said liquid crystal layer have alignment control layer for orientation of said liquid crystal parallel of same direction or reverse direction, and

the alignment of said liquid crystal layer is directed approximately in same direction or reverse direction.

5. The liquid crystal display device as claimed in any one of claims from 2 to 4, wherein;

the relationship, n_o ≦

n.sub. ≦

n_e, is established among the refractive indexes, n_o and n_e, of said nematic liquid crystal to ordinary light and extraordinary light and the refractive index, n_p, of the polymer matrix.

6. The liquid crystal display device as claimed in any one of claims from 2 to 4, wherein;

anisotropy of refractive index Δ

n (=n_e -n_o) of said nematic liquid crystal is at most 0.1.

7. The liquid crystal display device as claimed in any one of claims from 2 to 4, wherein;

said transparent polymer matrix is stretched uniaxially.

8. The liquid crystal display device as claimed in any one of claims from 2 to 4, wherein;

said transparent polymer matrix is liquid crystalline polymer.

10. The liquid crystal display device as claimed in any one of claims from 2 to 4, wherein;

thickness of said transparent polymer layer is at most 30 μ

m.

4. A liquid crystal display device characterized in:

comprising;

a set of substrates faced each other at least one of which is transparent,

transparent electrodes provided respectively to each facing plane of said substrates, and

a polymer layer held between said transparent electrodes, and that;

said polymer layer is composed of two layers, each of the layers is composed of nematic liquid crystal particles having dichroism and positive dielectric anisotropy dispersed in transparent polymer matrix,

said nematic liquid crystals in each of said layers are aligned approximately parallel to the plane of said substrate in a specific orientation, and

the orientation of the alignment of said two layers are so determined as to cross over each other almost orthogonally.

11. A liquid crystal display device characterized in:

comprising;

a set of substrates faced each other at least one of which is transparent,

transparent electrodes provided respectively to each facing plane of said substrates,

liquid crystal alignment control layers provided on said transparent electrodes,

two liquid crystal layers separated by a polymer layer and held between said set of substrates, thickness of said polymer is at most 10 times of the the thickness of said liquid crystal layers and

seal portions surrounding vicinity of said liquid crystal layer, and that;

said liquid crystal layer is nematic liquid crystal having dichroism and positive dielectric anisotropy,

said nematic liquid crystal is approximately parallel to the substrate plane and is aligned to a designated orientation, and

the orientation of alignment in said two layers of liquid crystal layers are crossing each other almost orthogonally.

12. The liquid crystal display device as claimed in claim 11, wherein;

said liquid crystal is nematic liquid crystal including dichromatic dye.

13. The liquid crystal display device as claimed in claim 11, wherein;

liquid crystal alignment control layers are formed on both sides of said polymer layer,

orientating direction of alignment of said liquid crystal alignment control layers on both sides mutually cross over almost orthogonally and are approximately parallel or reverse parallel to orientating direction of the alignment formed in said liquid crystal alignment control layer at opposite side beyond said liquid crystal layer.

14. The liquid crystal display device as claimed in claim 11, wherein;

said polymer layer has double structure comprising polymer materials which are stretched uniaxially,

said stretched directions mutually cross over almost orthogonally, and

orientating direction of the alignment formed in said liquid crystal alignment control layer at opposite side beyond said liquid crystal layer approximately coincides with the stretched direction.

15. The liquid crystal display device as claimed in claim 11, wherein;

thickness of said two layers of liquid crystal are approximately equal.

18. A projection type display apparatus comprising;

a white light source,

dichroic mirrors for dividing white light outgoing from said white light source into three primary colors,

elements for forming images by being driven and controlled in accordance with external signal of designated light divided by said mirrors,

mirrors for reflecting image light passing through said elements, and

lenses for projection of said reflected images mirrors to a screen,

characterized in that;

said elements are liquid crystal display devices comprising;

a set of substrates faced each other at least one of which is transparent,

transparent electrodes provided respectively to each facing plane of said substrates,

a light absorbing layer held between said transparent electrodes, and

an electric power source for applying electric field to said light absorbing layer through said transparent electrodes, in which;

said light absorbing layer is composed of two layers,

each of the layers has dichroism,

average light absorbing axis of the each layers without electric field is approximately parallel to the substrate plane and crossing each other almost orthogonally, and

said average light absorbing axis of the each layers changes the axis direction by applying of electric field.

19. A display apparatus characterized in having:

a liquid crystal display device comprising;

a set of substrates faced each other at least one of which is transparent,

transparent electrodes provided respectively to each facing plane of said substrates,

a light absorbing layer held between said transparent electrodes, and

an electric power source for applying electric field to said light absorbing layer through said transparent electrodes, in which

said light absorbing layer is composed of two layers,

each of the layers has dichroism,

average light absorbing axis of the each layers without electric field is approximately parallel to the substrate plane and crossing each other almost orthogonally, and

said average light absorbing axis of the each layers changes the axis direction by applying of electric field, and

a matrix electrode as said transparent electrode for operation of said display device.