Display element and display device
View Patent ↗An electrode is provided on one surface of each of a pair of substrates. On the other surface of each of the substrates, a polarizer is provided. The substrates are assembled together so that their surfaces on which the electrodes are formed face each other. Then, a medium is introduced between the substrates, to form a dielectric material layer. The medium is prepared by mixing a chiral agent in a negative type liquid crystalline compound.
1. A display element, comprising:
a pair of substrates, at least one of which is transparent; and
a material layer between the substrates,
the display element performing a display operation by applying a field between the substrates, and
the material layer including a medium whose optical anisotropy magnitude is changeable by and according to the field, and in which a twisted chiral structure is formed when optical anisotropy occurs, the twisted structure having only one chiral configuration and being structured with molecules of the medium oriented only in one twisting direction.
2. A display element as set forth in claim 1 , wherein:
the twisted structure has a twist pitch that is within a wavelength range of visible light, or smaller than the wavelength of visible light.
3. A display element as set forth in claim 1 , wherein:
the medium comprises a chiral agent.
4. A display element as set forth in claim 3 , wherein:
a ratio of the chiral agent to a sum of the medium and the chiral agent is not less than 8 wt % and not more than 80 wt %.
5. A display element as set forth in claim 3 , wherein:
a ratio of the chiral agent to a sum of the medium and the chiral agent is not less than 30 wt % and not more than 80 wt %.
6. A display element as set forth in claim 1 , wherein:
the medium is a chiral material that is chiral itself.
7. A display element as set forth in claim 1 , wherein:
the medium contains a rod-like molecule that shows negative dielectric anisotropy.
8. A display element as set forth in claim 1 , wherein:
the medium contains a negative type liquid crystalline compound.
9. A display element a set forth in claim 8 , wherein:
Δn×|Δε|>0.63,
where Δn is a refractive index anisotropy at 550 nm in a nematic phase of the negative type liquid crystalline compound, and |Δε| is an absolute value of a dielectric anisotropy at 1 kHz in the nematic phase of the negative type liquid crystalline compound.
10. A display element a set forth in claim 9 , wherein:
Δn>0.128 and |Δε|>4.9.
11. A display element a set forth in claim 9 , wherein:
Δn×|Δε| is 3.3 or more.
12. A display element a set forth in claim 9 , wherein:
Δn≧0.183 and |Δε|≧18.
13. A display element as set forth in claim 1 , wherein:
the medium contains a polar molecule.
14. A display element as set forth in claim 1 , wherein:
the medium is optically isotropic when no field is applied thereon, and becomes optically anisotropic when the field is applied thereon.
15. A display element as set forth in claim 1 , wherein:
the medium is optically anisotropic when no field is applied thereon, and becomes optically isotropic when a field is applied thereon.
16. A display element as set forth in claim 1 , wherein:
the molecules comprising the medium have or form an orderly structure when the field is applied thereon or when no field is applied thereon, the orderly structure being smaller than a visible light wavelength and changeable by and according to field application.
17. A display element as set forth in claim 1 , wherein:
the medium is a material that shows a cholesteric blue phase.
18. A display element as set forth in claim 1 , wherein:
the medium is a material that shows a smectic blue phase.
19. A display element as set forth in claim 1 , wherein:
the material layer is a dielectric material layer containing a dielectric material.
20. A display element as set forth in claim 1 , comprising:
a section for applying the field between the substrates.
21. A display element as set forth in claim 1 , wherein:
the field is an electric field; and
an electrode is provided on each substrate, the electrode for applying the electric field between the substrates.
22. A display element as set forth in claim 21 , wherein:
the display element shows optical isotropy when an electric field is applied or when no electric field is applied.
23. A display element as set forth in claim 22 , wherein:
the material layer is a dielectric material layer containing a dielectric material.
24. A display element as set forth in claim 23 , wherein:
the twisted structure has a twist pitch that is within a wavelength range of visible light, or smaller than a wavelength of the visible light.
25. A display element as set forth in claim 23 , wherein:
the medium contains a chiral agent.
26. A display element as set forth in claim 25 , wherein:
a ratio of the chiral agent to a sum of the medium and the chiral agent is not less than 8 wt % and not more than 80 wt %.
27. A display element as set forth in claim 25 , wherein:
a ratio of the chiral agent to a sum of the medium and the chiral agent is not less than 30 wt % and not more than 80 wt %.
28. A display element as set forth in claim 23 , wherein:
the medium is a chiral material that is chiral itself.
29. A display element as set forth in claim 23 , wherein:
the medium contains a rod-like molecule that shows negative dielectric anisotropy.
30. A display element as set forth in claim 23 , wherein:
the medium contains a negative type liquid crystalline compound.
31. A display element a set forth in claim 30 , wherein:
Δn×|Δε|>0.63,
where Δn is a refractive index anisotropy at 550 nm in a nematic phase of the negative type liquid crystalline compound, and |Δε| is an absolute value of a dielectric anisotropy at 1 kHz in the nematic phase of the negative type liquid crystalline compound.
32. A display element a set forth in claim 31 , wherein: Δn>0.128 and |Δε|>4.9.
33. A display element a set forth in claim 31 , wherein:
Δn×|Δε| is 3.3 or more.
34. A display element a set forth in claim 33 , wherein:
Δn≧0.183 and |εΔ|≧18.
35. A display element as set forth in claim 23 , wherein:
a refractive index of the medium is changeable proportionally to square of an electric field.
36. A display element as set forth in claim 23 , wherein:
the medium contains a polar molecule.
37. A display element as set forth in claim 23 , wherein:
the medium is optically isotropic when no electric field is applied thereon, and becomes optically anisotropic when an electric field is applied thereon.
38. A display element as set forth in claim 23 , wherein:
the medium is optically anisotropic when no electric field is applied thereon, and becomes optically isotropic when an electric field is applied thereon.
39. A display element as set forth in claim 23 , wherein:
the molecules comprising the medium have or form an orderly structure when an voltage is applied thereon or when no electric field is applied thereon, the orderly structure being smaller than a visible light wavelength and changeable by and according to voltage application.
40. A display element as set forth in claim 23 , wherein:
the medium is a material that shows a cholesteric blue phase.
41. A display element as set forth in claim 23 , wherein:
the medium is a material that shows a smectic blue phase.
42. A display device, comprising:
the display element as set forth in claim 23 .
43. A display device, comprising:
the display element as set forth in claim 1 .