Liquid crystal display element and a projection type liquid crystal display apparatus

• US 5,379,137 A
• Filed: 08/18/1993
• Issued: 01/03/1995
• Est. Priority Date: 03/27/1991
• Status: Expired due to Term

• Current Assignee: AG Technology Co., Ltd.
• Original Assignee: AG Technology Co., Ltd.
• Inventors: Niiyama, Satoshi, Gunjima, Tomoki, Hirai, Yoshinori
• Primary Examiner(s): GROSS, ANITA P
• Application Number:
  US08/108,009
• Time in Patent Office: 503 Days
• Field of Search: 359/51, 359/52, 359/93, 359/102
• US Class Current: 349/86
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals

Abstract

A liquid crystal display element comprises a pair of substrates provided with electrodes and a liquid crystal and solidified matrix composite material, disposed between the pair of substrates, which includes a nematic liquid crystal dispersed and held in a solidified matrix, the nematic liquid crystal being such that the refractive index of the liquid crystal is changed depending on states of applying a voltage wherein in a state, the refractive index of the liquid crystal substantially coincides with that of the solidified matrix to thereby pass light, and in the other state, the former does not coincide with the latter to thereby cause the scattering of light, wherein the refractive index anisotropy Δn of the liquid crystal used is 0.18 or higher, and the dielectric anisotropy Δε_LC of the liquid crystal used satisfies the relation of 5<Δε_LC <13.

Claims

1. A gray scale liquid crystal display element comprising

a pair of substrates provided with electrodes and

a liquid crystal and solidified matrix composite material, disposed between said pair of substrates which includes a nematic liquid crystal dispersed and held in a solidified matrix,

said nematic liquid crystal being such that the refractive index of said liquid crystal is changed depending on states of applying a voltage wherein in one state the refractive index of said liquid crystal substantially coincides with that of said solidified matrix to thereby pass light, and in another state the former does not coincide with the latter to thereby cause the scattering of light, characterized in that the refractive index anisotropy Δ

n of said liquid crystal used is 0.20≦

Δ

n,

and the dielectric anisotropy Δ

ε

_LC of said liquid crystal used satisfies the relationship of 5<

Δ

ε

_LC <

13,

and the average particle diameter R (μ

m) of said liquid crystal and solidified matrix composite material satisfies the relationship of 0.2<

R·

Δ

n<

0.7,

and the dielectric constant ε

_M of said liquid crystal and solidified matrix composite material, satisfies the relationship of Δ

ε

_LC <

1.45 ε

_M,

and the elastic constant K33 (10^-12 N) of said liquid crystal in said liquid crystal and solidified matrix composite material satisfies the relationship of 4(K33/η

)⁰.5 >

R>

(K33/Δ

ε

_LC)⁰.5.

9. The gray scale liquid crystal display element of any one of claims 1-8 wherein said solidified matrix is formed by evaporating solvent or water and curing a curable compound.

10. The gray scale liquid crystal display element of any one of claims 1-8 wherein said solidified matrix is formed by curing a photo-curable or heat-curable compound.

11. The gray scale liquid crystal display element of any one of claims 1-8 wherein said solidified matrix is a polymer matrix formed by curing a photo-curable acryl compound.

12. The gray scale liquid crystal display element of any one of claims 1-8 wherein said solidified matrix is a polymer matrix formed by curing a photo-curable acryl compound containing acrylate oligomer.

13. The gray scale liquid crystal display element of any one of claims 1-8 wherein Δ

ε

_LC ≦

11.6 and Δ

n≦

0.24 and said solidified matrix is a polymer matrix formed by curing a curable compound.

14. The gray scale liquid crystal display element of any one of claims 1-8 wherein said long axes of said liquid crystal particles are arranged at random in a three-dimensional manner.

2. A gray scale liquid crystal display element comprising

a pair of substrates provided with electrodes and

a liquid crystal and solidified matrix composite material, disposed between said pair of substrates which includes a nematic liquid crystal dispersed and held in a solidified matrix,

said nematic liquid crystal being such that the refractive index of said liquid crystal is changed depending on states of applying a voltage wherein in one state the refractive index of said liquid crystal substantially coincides with that of said solidified matrix to thereby pass light, and in another state the former does not coincide with the latter to thereby cause the scattering of light, characterized in that the refractive index anisotropy Δ

n of said liquid crystal used is 0.20≦

Δ

n,

and the dielectric anisotropy Δ

ε

_LC of said liquid crystal used satisfies the relationship of 5<

Δ

ε

_LC <

13,

and the average particle diameter R (μ

m) of said liquid crystal and solidified matrix composite material satisfies the relationship of 0.2<

R·

Δ

n<

0.7,

and the viscosity η

(cSt) of said liquid crystal satisfies the relationship of Δ

n² /η

>

0.0014,

and the elastic constant K33 (10^-12 N) of said liquid crystal in said liquid crystal and solidified matrix composite material satisfies the relationship of 4(K33/η

)⁰.5 >

R>

(K33/Δ

ε

_LC)⁰.5.

3. A gray scale liquid crystal display element comprising

a pair of substrates provided with electrodes and

a liquid crystal and solidified matrix composite material, disposed between said pair of substrates which includes a nematic liquid crystal dispersed and held in a solidified matrix,

said nematic liquid crystal being such that the refractive index of said liquid crystal is changed depending on states of applying a voltage wherein in one state the refractive index of said liquid crystal substantially coincides with that of said solidified matrix to thereby pass light, and in another state the former does not coincide with the latter to thereby cause the scattering of light, characterized in that the refractive index anisotropy Δ

n of said liquid crystal used is 0.20≦

Δ

n,

and the dielectric anisotropy Δ

ε

_LC of said liquid crystal used satisfies the relationship of 5<

Δ

ε

_LC <

13,

and the average particle diameter R (μ

m) of said liquid crystal and solidified matrix composite material satisfies the relationship of 0.2<

R·

Δ

n<

0.7,

and the electrode substrate gap d (μ

m) and the maximum effective voltage V applied to said liquid crystal and solidified matrix composite satisfies the relationship of

space="preserve" listing-type="equation">·

R<

d<

9·

R

and

space="preserve" listing-type="equation">0.6R·

V<

d<

1.6R·

V.

4. A gray scale liquid crystal display element comprising

a pair of substrates provided with electrodes and

a liquid crystal and solidified matrix composite material, disposed between said pair of substrates which includes a nematic liquid crystal dispersed and held in a solidified matrix,

said nematic liquid crystal being such that the refractive index of said liquid crystal is changed depending on states of applying a voltage wherein in one state the refractive index of said liquid crystal substantially coincides with that of said solidified matrix to thereby pass light, and in another state the former does not coincide with the latter to thereby cause the scattering of light, characterized in that the refractive index anisotropy Δ

n of said liquid crystal used is 0.20≦

Δ

n,

and the dielectric anisotropy Δ

ε

_LC of said liquid crystal used satisfies the relationship of 5<

Δ

ε

_LC <

13,

and the average particle diameter R (μ

m) of said liquid crystal and solidified matrix composite material satisfies the relationship of 0.2<

R·

Δ

n<

0.7,

and the dielectric constant ε

_M of said liquid crystal and solidified matrix composite material, satisfies the relationship of Δ

ε

_LC <

1.45 ε

_M,

and the electrode substrate gap d (μ

m) and the maximum effective voltage V applied to said liquid crystal and solidified matrix composite satisfies the relationship of

space="preserve" listing-type="equation">·

R<

d<

9·

R

and

space="preserve" listing-type="equation">0.6R·

V<

d<

1.6R·

V.

5. A gray scale liquid crystal display element comprising

a pair of substrates provided with electrodes and

a liquid crystal and solidified matrix composite material, disposed between said pair of substrates which includes a nematic liquid crystal dispersed and held in a solidified matrix,

said nematic liquid crystal being such that the refractive index of said liquid crystal is changed depending on states of applying a voltage wherein in one state the refractive index of said liquid crystal substantially coincides with that of said solidified matrix to thereby pass light, and in another state the former does not coincide with the latter to thereby cause the scattering of light, characterized in that the refractive index anisotropy Δ

n of said liquid crystal used is 0.20≦

Δ

n,

and the dielectric anisotropy Δ

ε

_LC of said liquid crystal used satisfies the relationship of 5<

Δ

ε

_LC <

13,

and the average particle diameter R (μ

m) of said liquid crystal and solidified matrix composite material satisfies the relationship of 0.2<

R·

Δ

n<

0.7,

and the viscosity η

(cSt) of said liquid crystal satisfies the relationship of Δ

n² /η

>

0.0014,

and the electrode substrate gap d (μ

m) and the maximum effective voltage V applied to said liquid crystal and solidified matrix composite satisfies the relationship of

space="preserve" listing-type="equation">·

R<

d<

9·

R

and

space="preserve" listing-type="equation">0.6R·

V<

d<

1.6R·

V.

6. A gray scale liquid crystal display element comprising

a pair of substrates provided with electrodes and

a liquid crystal and solidified matrix composite material, disposed between said pair of substrates which includes a nematic liquid crystal dispersed and held in a solidified matrix,

said nematic liquid crystal being such that the refractive index of said liquid crystal is changed depending on states of applying a voltage wherein in one state the refractive index of said liquid crystal substantially coincides with that of said solidified matrix to thereby pass light, and in another state the former does not coincide with the latter to thereby cause the scattering of light, characterized in that the refractive index anisotropy Δ

n of said liquid crystal used is 0.20≦

Δ

n,

and the dielectric anisotropy Δ

ε

_LC of said liquid crystal used satisfies the relationship of 5<

Δ

ε

_LC <

13,

and said liquid crystal dispersed and held in said solidified matrix is in the shape of an ellipse rotated about a long axis,

wherein the long axes of said liquid crystal particles are arranged at random, with respect to a line normal to an electrode surface.

7. A gray scale liquid crystal display element comprising

a pair of substrates provided with electrodes and

a liquid crystal and solidified matrix composite material, disposed between said pair of substrates which includes a nematic liquid crystal dispersed and held in a solidified matrix,

said nematic liquid crystal being such that the refractive index of said liquid crystal is changed depending on states of applying a voltage wherein in one state the refractive index of said liquid crystal substantially coincides with that of said solidified matrix to thereby pass light, and in another state the former does not coincide with the latter to thereby cause the scattering of light, characterized in that the refractive index anisotropy Δ

n of said liquid crystal used is 0.20≦

Δ

n,

and the dielectric anisotropy Δ

ε

_LC of said liquid crystal used satisfies the relationship of 5<

Δ

ε

_LC <

13,

and the dielectric constant ε

_M of said liquid crystal and solidified matrix composite material, satisfies the relationship of Δ

ε

_LC <

1.45 ε

_M,

and said liquid crystal dispersed and held in said solidified matrix is in the shape of an ellipse rotated about a long axis,

wherein the long axes of said liquid crystal particles are arranged at random, with respect to a line normal to an electrode surface.

8. A gray scale liquid crystal display element comprising

a pair of substrates provided with electrodes and

a liquid crystal and solidified matrix composite material, disposed between said pair of substrates which includes a nematic liquid crystal dispersed and held in a solidified matrix,

said nematic liquid crystal being such that the refractive index of said liquid crystal is changed depending on states of applying a voltage wherein in one state the refractive index of said liquid crystal substantially coincides with that of said solidified matrix to thereby pass light, and in another state the former does not coincide with the latter to thereby cause the scattering of light, characterized in that the refractive index anisotropy Δ

n of said liquid crystal used is 0.20≦

Δ

n,

and the dielectric anisotropy Δ

ε

_LC of said liquid crystal used satisfies the relationship of 5<

Δ

ε

_LC <

13,

and the viscosity η

(cSt) of said liquid crystal satisfies the relationship of Δ

n² /η

>

0.0014,

and said liquid crystal dispersed and held in said solidified matrix is in the shape of an ellipse rotated about a long axis,

wherein the long axes of said liquid crystal particles are arranged at random, with respect to a line normal to an electrode surface.

15. A projection type gray scale liquid crystal display apparatus comprising in combination

a projection light source,

a projection optical system and

a liquid crystal display element comprising

a pair of substrates provided with electrodes and

a liquid crystal and solidified matrix composite material, disposed between said pair of substrates, which includes a nematic liquid crystal dispersed and held in a solidified matrix,

said nematic liquid crystal being such that the refractive index of said liquid crystal is changed depending on states of applying a voltage wherein in one state the refractive index of said liquid crystal substantially coincides with that of said solidified matrix to thereby pass light, and in another state the former does not coincide with the latter to thereby cause the scattering of light, characterized in that the refractive index anisotropy Δ

n of said liquid crystal used is 0.20≦

Δ

n,

and the dielectric anisotropy Δ

ε

_LC of said liquid crystal used satisfies the relationship of 5<

Δ

ε

_LC <

13,

and the average particle diameter R (μ

m) of said liquid crystal and solidified matrix composite material satisfies the relationship of 0.2<

R·

Δ

n<

0.7,

and the dielectric constant ε

_M of said liquid crystal and solidified matrix composite material, satisfies the relationship of Δ

ε

_LC <

1.45 ε

_M,

and the elastic constant K33 (10^-12 N) of said liquid crystal in said liquid crystal and solidified matrix composite material satisfies the relationship of 4(K33/η

)⁰.5 >

R>

(K33/Δ

ε

_LC)⁰.5.

23. The projection type gray scale liquid crystal display apparatus of any one of claims 15-22 wherein three liquid crystal display elements are arranged, and

said projection light source comprises a light source and a dichroic means as a color-splitting optical system;

said projection optical system comprises a dichroic means as a color-synthesizing optical system and a projection lens;

whereby light is split into three kinds of color, R, G, and B, each color light being passed through each liquid crystal display element, being subjected to color synthesis and the synthesized light being projected through said projection lens.

24. The projection type gray scale liquid crystal display apparatus of any one of claims 15-22 wherein an aperture for reducing diffusion light is disposed between said liquid crystal display element and said projection optical system, or in said projection optical system.

25. The projection type gray scale liquid crystal display apparatus of any one of claims 15-22 wherein three liquid crystal display elements for splitting light into three kinds of color, R, G, and B light are arranged and electrode substrate gaps d_R, d_G, and d_B of the respective liquid crystal display elements have the relationship

27. The projection type gray scale liquid crystal display apparatus of any one of claims 15-22 wherein said liquid crystal display element is applied in a reflection type display.

16. A projection type gray scale liquid crystal display apparatus comprising in combination

a projection light source,

a projection optical system and

a liquid crystal display element comprising

a pair of substrates provided with electrodes and

a liquid crystal and solidified matrix composite material, disposed between said pair of substrates, which includes a nematic liquid crystal dispersed and held in a solidified matrix,

said nematic liquid crystal being such that the refractive index of said liquid crystal is changed depending on states of applying a voltage wherein in one state the refractive index of said liquid crystal substantially coincides with that of said solidified matrix to thereby pass light, and in another state the former does not coincide with the latter to thereby cause the scattering of light, characterized in that the refractive index anisotropy Δ

n of said liquid crystal used is 0.20≦

Δ

n,

and the dielectric anisotropy Δ

ε

_LC of said liquid crystal used satisfies the relationship of 5<

Δ

ε

_LC <

13,

and the average particle diameter R (μ

m) of said liquid crystal and solidified matrix composite material satisfies the relationship of 0.2<

R·

Δ

n<

0.7,

and the viscosity η

(cSt) of said liquid crystal satisfies the relationship of Δ

n² /η

>

0.0014,

and the elastic constant K33 (10^-12 N) of said liquid crystal in said liquid crystal and solidified matrix composite material satisfies the relationship of 4(K33/η

)⁰.5 >

R>

(K33/Δ

ε

_LC)⁰.5.

17. A projection type gray scale liquid crystal display apparatus comprising in combination

a projection light source,

a projection optical system and

a liquid crystal display element comprising

a pair of substrates provided with electrodes and

a liquid crystal and solidified matrix composite material, disposed between said pair of substrates, which includes a nematic liquid crystal dispersed and held in a solidified matrix,

said nematic liquid crystal being such that the refractive index of said liquid crystal is changed depending on states of applying a voltage wherein in one state the refractive index of said liquid crystal substantially coincides with that of said solidified matrix to thereby pass light, and in another state the former does not coincide with the latter to thereby cause the scattering of light, characterized in that the refractive index anisotropy Δ

n of said liquid crystal used is 0.20≦

Δ

n,

and the dielectric anisotropy Δ

ε

_LC of said liquid crystal used satisfies the relationship of 5<

Δ

ε

_LC <

13,

and the average particle diameter R (μ

m) of said liquid crystal and solidified matrix composite material satisfies the relationship of 0.2<

R·

Δ

n<

0.7,

and the electrode substrate gap d (μ

m) and the maximum effective voltage V applied to said liquid crystal and solidified matrix composite satisfies the relationship of

space="preserve" listing-type="equation">3·

R<

d<

9·

R

and

space="preserve" listing-type="equation">0.6R·

V<

d<

1.6R·

V.

18. A projection type gray scale liquid crystal display apparatus comprising in combination

a projection light source,

a projection optical system and

a liquid crystal display element comprising

a pair of substrates provided with electrodes and

a liquid crystal and solidified matrix composite material, disposed between said pair of substrates, which includes a nematic liquid crystal dispersed and held in a solidified matrix,

said nematic liquid crystal being such that the refractive index of said liquid crystal is changed depending on states of applying a voltage wherein in one state the refractive index of said liquid crystal substantially coincides with that of said solidified matrix to thereby pass light, and in another state the former does not coincide with the latter to thereby cause the scattering of light, characterized in that the refractive index anisotropy Δ

n of said liquid crystal used is 0.20≦

Δ

n,

and the dielectric anisotropy Δ

ε

_LC of said liquid crystal used satisfies the relationship of 5<

Δ

ε

_LC <

13,

and the average particle diameter R (μ

m) of said liquid crystal and solidified matrix composite material satisfies the relationship of 0.2<

R·

Δ

n<

0.7,

and the dielectric constant ε

_M of said liquid crystal and solidified matrix composite material, satisfies the relationship of Δ

ε

_LC <

1.45 ε

_M,

and the electrode substrate gap d (μ

m) and the maximum effective voltage V applied to said liquid crystal and solidified matrix composite satisfies the relationship of

space="preserve" listing-type="equation">3·

R<

d<

9·

R

and

space="preserve" listing-type="equation">0.6R·

V<

d<

1.6R·

V.

19. A projection type gray scale liquid crystal display apparatus comprising in combination

a projection light source,

a projection optical system and

a liquid crystal display element comprising

a pair of substrates provided with electrodes and

a liquid crystal and solidified matrix composite material, disposed between said pair of substrates, which includes a nematic liquid crystal dispersed and held in a solidified matrix,

said nematic liquid crystal being such that the refractive index of said liquid crystal is changed depending on states of applying a voltage wherein in one state the refractive index of said liquid crystal substantially coincides with that of said solidified matrix to thereby pass light, and in another state the former does not coincide with the latter to thereby cause the scattering of light, characterized in that the refractive index anisotropy Δ

n of said liquid crystal used is 0.20≦

Δ

n,

and the dielectric anisotropy Δ

ε

_LC of said liquid crystal used satisfies the relationship of 5<

Δ

ε

_LC <

13,

and the average particle diameter R (μ

m) of said liquid crystal and solidified matrix composite material satisfies the relationship of 0.2<

R·

Δ

n<

0.7,

and the viscosity η

(cSt) of said liquid crystal satisfies the relationship of Δ

n² /η

>

0.0014,

and the electrode substrate gap d (μ

m) and the maximum effective voltage V applied to said liquid crystal and solidified matrix composite satisfies the relationship of

space="preserve" listing-type="equation">·

R<

d<

9·

R

and

space="preserve" listing-type="equation">0.6R·

V<

d<

1.6R·

V.

20. A projection type gray scale liquid crystal display apparatus comprising in combination

a projection light source,

a projection optical system and

a liquid crystal display element comprising

a pair of substrates provided with electrodes and

a liquid crystal and solidified matrix composite material, disposed between said pair of substrates, which includes a nematic liquid crystal dispersed and held in a solidified matrix,

said nematic liquid crystal being such that the refractive index of said liquid crystal is changed depending on states of applying a voltage wherein in one state the refractive index of said liquid crystal substantially coincides with that of said solidified matrix to thereby pass light, and in another state the former does not coincide with the latter to thereby cause the scattering of light, characterized in that the refractive index anisotropy Δ

n of said liquid crystal used is 0.20≦

Δ

n,

and the dielectric anisotropy Δ

ε

_LC of said liquid crystal used satisfies the relationship of 5<

Δ

ε

_LC <

13,

and said liquid crystal dispersed and held in said solidified matrix is in the shape of an ellipse rotated about a long axis, wherein the long axes of said liquid crystal particles are arranged at random, with respect to a line normal to an electrode surface.

26. The projection type gray scale liquid crystal display apparatus of any one of claims 20-22 wherein said long axes of said liquid crystal particles are arranged at random in a three-dimensional manner.

21. A projection type gray scale liquid crystal display apparatus comprising in combination

a projection light source,

a projection optical system and

a liquid crystal display element comprising

a pair of substrates provided with electrodes and

a liquid crystal and solidified matrix composite material, disposed between said pair of substrates, which includes a nematic liquid crystal dispersed and held in a solidified matrix,

said nematic liquid crystal being such that the refractive index of said liquid crystal is changed depending on states of applying a voltage wherein in one state the refractive index of said liquid crystal substantially coincides with that of said solidified matrix to thereby pass light, and in another state the former does not coincide with the latter to thereby cause the scattering of light, characterized in that the refractive index anisotropy Δ

n of said liquid crystal used is 0.20≦

Δ

n,

and the dielectric anisotropy Δ

ε

_LC of said liquid crystal used satisfies the relationship of 5<

Δ

ε

_LC <

13,

and the dielectric constant ε

_M of said liquid crystal and solidified matrix composite material, satisfies the relationship of Δ

ε

_LC <

1.45 ε

_M,

and said liquid crystal dispersed and held in said solidified matrix is in the shape of an ellipse rotated about a long axis, wherein the long axes of said liquid crystal particles are arranged at random, with respect to a line normal to an electrode surface.

22. A projection type gray scale liquid crystal display apparatus comprising in combination

a projection light source,

a projection optical system and

a liquid crystal display element comprising

a pair of substrates provided with electrodes and

a liquid crystal and solidified matrix composite material, disposed between said pair of substrates, which includes a nematic liquid crystal dispersed and held in a solidified matrix,

said nematic liquid crystal being such that the refractive index of said liquid crystal is changed depending on states of applying a voltage wherein in one state the refractive index of said liquid crystal substantially coincides with that of said solidified matrix to thereby pass light, and in another state the former does not coincide with the latter to thereby cause the scattering of light, characterized in that the refractive index anisotropy Δ

n of said liquid crystal used is 0.20≦

Δ

n,

and the dielectric anisotropy Δ

ε

_LC of said liquid crystal used satisfies the relationship of 5<

Δ

ε

_LC <

13,

and the viscosity η

(cSt) of said liquid crystal satisfies the relationship of Δ

n² /η

>

0.0014,

and said liquid crystal dispersed and held in said solidified matrix is in the shape of an ellipse rotated about a long axis, wherein the long axes of said liquid crystal particles are arranged at random, with respect to a line normal to an electrode surface.