Anisotropic fluorescent thin crystal film and backlight system and liquid crystal display incorporating the same

1. A backlight system comprising:

at least one light source emitting light with an emission spectrum with at least one peak in a wavelength range between 250 and 450 nm, and

an anisotropic fluorescent thin crystal film (AF TCF) placed on a light path of the light emitted by the light source,

wherein said AF TCF is formed by rodlike supramolecules composed of disc-shaped molecules of at least one polycyclic organic compound which is a product of sulfonation of at least one of the group consisting of

Bisbenzimidazo[2,1-b:1′,2′-j]benzo[lmn][3,8]phenanthroline-6,9-dione, and

7H-Benzimidazo[2,1-a]benz[de]isoquinolin-7-one,

wherein said rodlike supramolecules has a preferable alignment direction, and emitting polarized visible light when irradiated by light within said wavelength range.

2. The backlight system according to claim 1 , wherein the emission spectrum has at least one peak in the wavelength range between 260 and 380 nm.

3. The backlight system according to claim 2 , wherein said light source is selected from the group comprising plasma sources of optical radiation, luminescent sources of optical radiation, and lasers.

4. The backlight system according to claim 1 , further including a light collimator placed to collimate the light output from the system.

5. The backlight system according to claim 4 , further including a polarizer of visible light placed after AF TCF in the light path of the light emitted by the light source.

6. The backlight system according to claim 5 , wherein said preferable alignment direction is parallel to the absorption axis of the polarizer of visible light.

7. The backlight system according to claim 1 , further including a reflector for reflecting the light emitted by the light source and the light fluoresced by AF TCF.

8. The backlight system according to claim 7 , wherein said reflector is specular.

9. The backlight system according to claim 7 , wherein said reflector is diffuse.

10. The backlight system according to claim 7 , wherein said reflector is oriented at the Brewster angle.

11. The backlight system according to claim 7 , wherein the reflector has a surface covered with a network of grooves, which are substantially V-shaped.

12. The backlight system according to claim 10 , wherein the AF TCF is placed on top of the reflector.

13. The backlight system according to claim 7 , further including a reflective polarizer placed to receive the emitted polarized light.

14. The backlight system according to claim 13 , further including a quarter-wave plate placed between the reflective polarizer and the reflector.

15. The backlight system according to claim 13 , wherein the transmission axis of the reflective polarizer is perpendicular to said alignment direction.

16. The backlight system according to claim 1 , wherein the AF TCF has an interplanar spacing of 3.4±03 Å along said preferred direction.

17. The backlight system according to claim 1 , wherein at least one said polycyclic organic compound with disc-shaped molecules contains heterocycles.

18. The backlight system according to claim 5 , wherein the AF TCF is formed from a lyotropic liquid crystal.

19. The backlight system according to claim 1 , further comprising a retarder.

20. The backlight system according to claim 1 , further comprising a color filter.

21. An anisotropic fluorescent thin crystal film (AF TCF) for use in a backlight system, comprising at least one layer formed by rodlike supramolecules comprising disc-shaped molecules of at least one polycyclic organic compound which is a product of sulfonation of at least one of the group consisting of

Bisbenzimidazo[2,1-b:1′,2′-j]benzo[lmn][3,8]phenanthroline-6,9-dione, and

7H-Benzimidazo[2,1-a]benz[de]isoquinolin-7-one,

wherein the rodlike supramolecules have a preferable alignment direction and emit polarized visible light when irradiated in the wavelength range between 250 and 450 nm.

22. The AF TCF according to claim 21 , wherein at least one said polycyclic organic compound with disc-shaped molecules contains heterocycles.

23. The AF TCF according to claim 21 , wherein an interplanar spacing along said direction is 3.4±03 Å.

24. The AF TCF according to claim 21 , wherein said layer serves as a polarizer of visible light and/or a retarder.

25. The AF TCF according to claim 21 , wherein the film further comprising a polarizer.

26. The AF TCF according to claim 21 , wherein the film further comprising a retarder.

27. The AF TCF according to claim 21 , wherein the film further comprising a color filter.

28. A liquid crystal display, comprising

a liquid crystal cell, and

a backlight system comprising

a light source emitting light with an emission spectrum with at least one peak in a wavelength range between 250 and 450 nm, and

an anisotropic fluorescent thin crystal film (AF TCF) placed on a light path of the light emitted by the light source,

wherein said AF TCF is formed by rodlike supramolecules composed of the disc-shaped molecules of at least one polycyclic organic compound which is a product of sulfonation of at least one of the group consisting of

Bisbenzimidazo[2,1-b:1′,2′-j]benzo[lmn][3,8]phenanthroline-6,9-dione, and

7H-Benzimidazo[2,1-a]benz[de]isoquinolin-7-one,

wherein the rodlike supramolecules have preferable alignment direction and emitting polarized visible light when irradiated by light from said wavelength range.

29. A liquid crystal display comprising

a liquid crystal cell, and

a backlight system as in claim 4 .

30. The backlight system according to claim 11 , wherein the AF TCF is placed on top of the reflector.

31. A liquid crystal display comprising a liquid crystal cell, and

a backlight system as any one of claims 7 - 17 and 30 .