Display Element And Display Device

• US 20080106689A1
• Filed: 08/24/2005
• Published: 05/08/2008
• Est. Priority Date: 08/31/2004
• Status: Abandoned Application

• Current Assignee: Iichiro Inoue, Koichi Miyachi, Seiji Shibahara, Shoichi Ishihara
• Original Assignee: Iichiro Inoue, Koichi Miyachi, Seiji Shibahara, Shoichi Ishihara
• Inventors: Ishihara, Shoichi, Inoue, Iichiro, Miyachi, Koichi, Shibahara, Seiji
• Application Number:
  US10/574,505
• Publication Number:
  US 20080106689A1
• Time in Patent Office: Days
• US Class Current: 349/181
• CPC Class Codes: C09K 19/22 linked by a chain containing carbon and nitrogen atoms as chain links, e.g. Schiff bases
• CPC Class Codes: C09K 19/24 linked by a chain containing nitrogen-to-nitrogen bonds
• CPC Class Codes: C09K 19/3028 in which at least two rings are linked by a carbon chain containing carbon to carbon single bonds
• CPC Class Codes: C09K 19/3068 chain containing -COO- or -OCO- groups
• CPC Class Codes: C09K 19/3444 the heterocyclic ring being a six-membered aromatic ring containing one nitrogen atom, e.g. pyridine
• CPC Class Codes: C09K 2019/0407 containing a carbocyclic ring, e.g. dicyano-benzene, chlorofluoro-benzene or cyclohexanone
• CPC Class Codes: C09K 2019/0481 Phenylene substituted in meta position
• CPC Class Codes: C09K 2019/3027 Compounds comprising 1,4-cyclohexylene and 2,3-difluoro-1,4-phenylene
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
• CPC Class Codes: G02F 1/13731 based on a field-induced phase transition G02F1/13781 takes precedence
• CPC Class Codes: G02F 1/139 based on orientation effects in which the liquid crystal remains transparent
• CPC Class Codes: G02F 1/1393 the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells G02F1/1396, G02F1/141 take precedence

Abstract

A display element of the present invention includes: a pair of substrates which are opposed to each other; and a substance layer, which is sandwiched between the substrates, exhibiting an optical isotropy when no electric field is applied, while exhibiting an optical anisotropy when an electric field is applied, and the display element performs display operation by applying an electric field to between the substrates. The substance layer includes a liquid crystalline medium exhibiting a nematic liquid crystal phase, and it is Δn×|Δ∈|≧1.9, where Δn is a refractive index anisotropy at 550 nm in a nematic phase of the liquid crystalline medium, and |Δ∈| is an absolute value of a dielectric anisotropy at 1 kHz in the nematic phase of the liquid crystalline medium. The display element and a display device including the display element realize a fast response speed and a low driving voltage and driving in a wide temperature range.

Claims

1. A display element, comprising:

a pair of substrates which are opposed to each other; and

a substance layer sandwiched between the substrates,

the display element performing display operation by applying an electric field to between the substrates,

the substance layer including a liquid crystalline medium exhibiting a nematic liquid crystal phase, and exhibiting an optical isotropy when no electric field is applied, while exhibiting an optical anisotropy when an electric field is applied,

wherein;

Δ

n×

|Δ

∈

|≧

1.9,

where Δ

n is a refractive index anisotropy at 550 nm in a nematic phase of the liquid crystalline medium exhibiting the nematic liquid crystal phase, and |Δ

∈

| is an absolute value of a dielectric anisotropy at 1 kHz in the nematic phase of the liquid crystalline medium exhibiting the nematic liquid crystal phase.

2. The display element according to claim 1, wherein:

Δ

n≧

0.14 and |Δ

∈

|≧

14.

3. The display element according to claim 1, wherein:

Δ

n×

|Δ

∈

|≧

4.0.

4. The display element according to claim 3, wherein:

Δ

n≧

0.2 and |Δ

∈

|≧

20.

5. The display element according to claim 1, wherein:

Δ

∈

is negative.

6. The display element according to claim 1, wherein:

an orientation auxiliary material is provided between the substrates, the orientation auxiliary material functioning to promote exhibition of an optical anisotropy by application of the electric field.

7. The display element according to claim 6, wherein:

the orientation auxiliary material is formed in the substance layer.

8. The display element according to claim 7, wherein:

the orientation auxiliary material has a structural anisotropy.

9. The display element according to claim 7, wherein:

the orientation auxiliary material is formed in a state where the liquid crystalline medium in the substance layer is in a liquid crystal phase.

10. The display element according to claim 7, wherein:

the orientation auxiliary material is made of a polymerizable compound.

11. The display element according to claim 7, wherein:

the orientation auxiliary material is made of a polymer compound.

12. The display element according to claim 11, wherein:

the orientation auxiliary material is made of at least one polymer compound selected from the group consisting of a chain polymer compound, a network polymer compound, and a cyclic polymer compound.

13. The display element according to claim 7, wherein:

the orientation auxiliary material is made of hydrogen bonding material.

14. The display element according to claim 7, wherein:

the orientation auxiliary material is made of porous material.

15. The display element according to claim 7, wherein:

the orientation auxiliary material divides the liquid crystalline medium in the substance layer into small regions.

16. The display element according to claim 15, wherein:

the small region has a size of not more than a visible light wavelength.

17. The display element according to claim 7, wherein:

the orientation auxiliary material is a horizontal alignment film which is provided in at least one of the substrates.

18. The display element according to claim 17, wherein:

the horizontal alignment film is subjected to rubbing treatment or light irradiation treatment.

19. The display element according to claim 18, wherein:

the horizontal alignment film is provided in each of the substrates, and is arranged so that rubbing directions in the rubbing treatment or light irradiation directions in the light irradiation treatment are parallel or antiparallel to each other.

20. The display element according to claim 19) wherein:

said display element satisfies λ

/4≦

Δ

n×

d≦

3λ

/4 where d (μ

m) is a thickness of the substance layer, and λ

(nm) is a wavelength of incident light.

21. The display element according to claim 18, wherein:

the horizontal alignment film is provided in each of the substrates, and is arranged so that rubbing directions in the rubbing treatment or light irradiation directions in the light irradiation treatment are orthogonal to each other.

22. The display element according to claim 21, wherein:

said display element satisfies 350 (nm)≦

Δ

n×

d≦

650 (nm) where d (μ

m) is a thickness of the substance layer.

23. The display element according to claim 1, wherein:

the substance layer further includes particulates sealed therein.

25. The display element according to claim 1, wherein:

the substance layer has sealed therein a medium containing polar molecules.

26. The display element according to claim 1, wherein:

the substance layer takes a twisted structure with only one chirality.

27. The display element according to claim 1, wherein:

the substance layer has sealed therein a medium exhibiting chirality.

28. The display element according to claim 1, wherein:

the liquid crystalline medium has a selective reflection wavelength band or a helical pitch of not more than 400 nm.

31. A display device including the display element according to claim 1.

24. (canceled)

29. (canceled)

30. (canceled)