Encapsulated liquid crystal and method

• US 4,605,284 A
• Filed: 06/29/1984
• Issued: 08/12/1986
• Est. Priority Date: 09/16/1981
• Status: Expired due to Term

• Current Assignee: Manchester R & D Partnership
• Original Assignee: Manchester R & D Partnership
• Inventors: Fergason, James L.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Gallivan, Richard F.
• Application Number:
  US06/626,425
• Time in Patent Office: 774 Days
• Field of Search: 350/334, 350/344, 350/351
• US Class Current: 349/86
• CPC Class Codes: C09K 19/544 as dispersing or encapsulating medium around the liquid crystal
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
• CPC Class Codes: G02F 2202/043 pleochroic

Abstract

Briefly, according to one aspect of the invention, liquid crystal material, and especially nematic material, is encapsulated; according to another aspect the encapsulated liquid crystal material is used in liquid crystal devices, such as relatively large size visual display devices; and according to further aspects there are provided methods for encapsulating liquid crystal material and for making a liquid crystal device using such encapsulated liquid crystal material.

Claims

1. Liquid crystal apparatus, comprising liquid crystal material, and containment means for inducing a generally non-parallel alignment of said liquid crystal material which in response to such alignment at least one of scatters and absorbs light and which in response to a prescribed input reduces the amount of such scattering or absorption, said liquid crystal material and containment means comprising a dispersion thereof.

2. Liquid crystal apparatus, comprising liquid crystal material, and containment means for inducing a generally non-parallel alignment of said liquid crystal material which in response to such alignment at least one of scatters and absorbs light and which in response to a prescribed input reduces the amount of such scattering or absorption, said containment means forming capsule-like volumes for containing said liquid crystal material, said volumes being of a diameter of from about 0.3 microns to about 100 microns.

3. The invention of claim 2, said volumes being of a diameter of from about 1 micron to about 30 microns.

4. The invention of claim 3, said volumes being of a diameter of from about 3 microns to about 15 microns.

5. The invention of claim 4, said volumes being of a diameter of from about 5 microns to about 15 microns.

6. The invention of claim 2, further comprising substrate means for supporting a layer of said liquid crystal material and containment means.

7. The invention of claim 6, said layer being from about 0.3 mil to about 10 mils thick.

8. The invention of claim 6, said layer comprising several layers of capsule-like volumes in thickness.

9. The invention of claim 2, further comprising substrate means for supporting a layer of said liquid crystal material and containment means, a first electrode positioned between said substrate means and said layer, and a second electrode positioned on the opposite side of said layer relative to said substrate means.

10. The invention of claim 9, said first electrode being positioned over substantially the entire surface of said substrate means where said layer is supported on the latter.

11. The invention of claim 10, said second electrode being positioned only over predetermined selected areas, less than the entire area, of said layer.

12. The invention of claim 9, said substrate means having a thickness of about 10 mils, said first electrode having a thickness of about 200 Angstroms, said second electrode having a thickness of about 0.5 mil, and said layer having a thickness of from about 0.3 mil to about 10 mils.

13. The invention of claim 2, said capsule-like volumes of liquid crystal being silk-screened for support on said substrate means.

14. The invention of claim 9, said capsule-like volumes of liquid crystal being silk-screened for support on said substrate means.

15. The invention of claim 2, further comprising pleochroic dye mixed with said liquid crystal material.

16. The invention of claim 2, wherein the invention is operative independent of polarization of light incident thereon.

17. The invention of claim 2, wherein said prescribed input is an AC electrical field or a DC electrical field.

18. Liquid crystal material and a medium for containing discrete quantities of such liquid crystal material, said material having positive dielectric anisotropy, and wherein the difference between the ordinary index of refraction of said liquid crystal material and the index of refraction of said medium being no greater than 0.03.

19. The invention of claim 18, wherein said difference in indices of refraction being no greater than 0.01.

20. The invention of claim 18, wherein the difference between said indices of refraction is no greater than 0.001.

21. The invention of claim 18, further comprising pleochroic dye mixed with said liquid crystal material.

22. The invention of claim 18, wherein the invention is operative independent of polarization of light incident thereon.

23. Liquid crystal material and a medium for containing discrete quantities of such liquid crystal material, said material having positive dielectric anisotropy, said medium having a dielectric constant that is no less than the lower dielectric constant value of said material and such lower dielectric constant being from about 3.5 to about 8.

24. The invention of claim 23, wherein said prescribed input is an AC electrical field or a DC electrical field.

25. A method of making encapsulated nematic liquid crystals, comprising mixing at least an encapsulating medium and a nematic liquid crystal material, and further comprising selecting such liquid crystal material and such encapsulating medium such that the liquid crystal material has a positive dielectric anisotropy and the dielectric constant of such encapsulating medium is at least as great as the lower dielectric constant of such liquid crystal material and such lower dielectric constant is from about 3.5 to about 8.

26. A method of making encapsulated nematic liquid crystals, comprising mixing at least an encapsulating medium and a nematic liquid crystal material, and further comprising selecting such liquid crystal material and such encapsulating medium such that the difference between the ordinary index of refraction of the liquid crystal material and the index of refraction of the encapsulating medium is not greater than about 0.03.

27. The invention of claim 26, wherein such difference is not greater than about 0.01.

28. The invention of claim 26, wherein such difference is not greater than about 0.001.