LIQUID CRYSTAL CELL

• US 20140285751A1
• Filed: 06/06/2014
• Published: 09/25/2014
• Est. Priority Date: 12/06/2011
• Status: Active Grant

• Current Assignee: LG Chem Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: MIN, Sung Joon, OH, Dong Hyun, CHANG, Jun Won, KIM, Kyung Jun, JEONG, Hye Won, PARK, Moon Soo
• Granted Patent: US 9,182,624 B2
• Time in Patent Office: Days
• US Class Current: 349/88
• CPC Class Codes: C09K 19/60 Pleochroic dyes
• CPC Class Codes: C09K 2019/0448 the end chain group being a polymerizable end group, e.g. -Sp-P or acrylate
• CPC Class Codes: C09K 2019/2078 Ph-COO-Ph-COO-Ph
• CPC Class Codes: C09K 2019/546 creating a polymeric network
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
• CPC Class Codes: G02F 1/13345 Network or three-dimensional gels
• CPC Class Codes: G02F 1/13725 based on guest-host interaction G02F1/13762, G02F1/13737, take precedence

Abstract

The present application relates to a liquid crystal cell, a method for preparing a liquid crystal cell and a display device. An exemplary liquid crystal cell may be applied to various types of display devices so as to control a viewing angle or light transmittance of the display device.

Claims

1. A liquid crystal cell, comprising:

a liquid crystal layer, comprising;

a polymer network; and

a region which is in the polymer network, and which comprises a liquid crystal compound and a dichroic dye having a dichroic ratio of 7 or more in at least a part of a wavelength range of a visible region.

2. The liquid crystal cell according to claim 1, wherein the polymer network and the liquid crystal compound satisfy Equation 1 below:

(1−

a)×

{(2n_o²+n_e²)/3}^0.5<

n_p<

(1+a)×

{(2n_o²+n_e²)/3}^0.5 

 

[Equation 1]

where n_p is a refractive index of the polymer network, n_o is an ordinary refractive index of the liquid crystal compound, n_e is an extraordinary refractive index of the liquid crystal compound, and a is a number satisfying 0≦

a<

0.5.

3. The liquid crystal cell according to claim 1, wherein a dielectric anisotropy of the polymer network is 3 or more.

4. The liquid crystal cell according to claim 1, wherein the liquid crystal compound is a nematic liquid crystal compound satisfying Equation 2:

(1.53−

b)<

{(2n_o²+n_e²)/3}^0.5<

(1.53+b) 

 

[Equation 2]

where n_o is an ordinary refractive index of the liquid crystal compound, n_e is an extraordinary refractive index of the liquid crystal compound, and b is a number satisfying 0.1≦

b≦

1.

5. The liquid crystal cell according to claim 1, wherein a difference (∈

_e−

∈

_o) between an extraordinary dielectric anisotropy (∈

_e) of the liquid crystal compound and an ordinary dielectric anisotropy (∈

_o) of the liquid crystal compound is 3 or more.

6. The liquid crystal cell according to claim 1, of which a light transmittance under a state where a voltage is not applied is 80% or more.

7. The liquid crystal cell according to claim 1, wherein the polymer network is an alignable network of a precursor material compound a photo-alignable compound.

8. The liquid crystal cell according to claim 7, wherein the photo-alignable compound is orientationally ordered, and the liquid crystal compound or the dichroic dye is aligned by the ordered network.

9. The liquid crystal cell according to claim 1, further comprising an alignable layer disposed adjacent to the liquid crystal layer, and the polymer network being a network comprising a polymerizable liquid crystal compound aligned by the alignable layer.

10. The liquid crystal cell according to claim 1, wherein the dichroic dye is a black dye.

12. The liquid crystal cell according to claim 1, further comprising two base layers disposed so as to face each other, and the liquid crystal layer being formed between the two facing base layers.

13. The liquid crystal cell according to claim 12, wherein an electrode layer is formed on the side facing the liquid crystal layer of the base layer.

14. The liquid crystal cell according to claim 1, wherein the liquid crystal compound and the dichroic dye are convertable between a homogeneous alignment state and a homeotropic alignment state.

15. The liquid crystal cell according to claim 1, further comprising a polarizing plate on one surface of the liquid crystal layer, and the liquid crystal compound or dichroic dye being aligned in a direction parallel to a light absorption axis of the polarizing plate under a state where a voltage is not applied.

16. A method of manufacturing the liquid crystal cell of claim 1, comprising:

irradiating a layer of a precursor comprising a precursor material of an alignable network comprising an alignable compound, a liquid crystal compound and a dichroic dye with light.

17. A method of manufacturing the liquid crystal cell of claim 1, comprising irradiating a layer of a precursor which is formed on an alignable layer and which comprises a precursor material of a polymer network, a liquid crystal compound and a dichroic dye with light.

18. A display device, comprising:

a display element; and

the liquid crystal cell of claim 1 on one surface of the display element.

19. The display device according to claim 18, wherein the display element comprises a display panel and a polarizing plate, and the polarizing plate is between the display panel and the liquid crystal cell.

20. The display device according to claim 19, wherein the display panel is an organic light emitting display panel or a liquid crystal panel.

11. (canceled)