Luminance adjustment film and illuminating device including a photoisomerizable compound

1. A luminance adjustment film comprising:

at least one microcapsule containing a photoisomerizable compound which selectively decreases luminance of visible light in reaction to ultraviolet light having an intensity distribution which reflects a luminance distribution of the visible light.

2. The luminance adjustment film of claim 1 , wherein the photoisomerizable compound selectively decreases the luminance of the visible light so as to correct unevenness in the luminance distribution of the visible light.

3. The luminance adjustment film of claim 1 , wherein the photoisomerizable compound selectively scatters the visible light so as to selectively decrease the luminance of the visible light when an intensity of the ultraviolet light is greater than or equal to a certain intensity.

4. The luminance adjustment film of claim 3 , wherein the photoisomerizable compound is precipitated in the at least one microcapsule so as to selectively scatter the visible light.

5. The luminance adjustment film of claim 1 , wherein the visible light passes through the photoisomerizable compound when an intensity of the ultraviolet light is less than a certain intensity.

6. The luminance adjustment film of claim 1 , wherein the at least one microcapsule is coated with a polycondensation resin.

7. The luminance adjustment film of claim 6 , wherein the polycondensation resin is formed of a melamine resin, a urea resin, a gelatin resin, a urethane resin, or a polyurea resin.

8. The luminance adjustment film of claim 1 , further comprising a transparent resin in which the at least one microcapsule is contained.

9. The luminance adjustment film of claim 8 , wherein the transparent resin comprises polyethylene, polypropylene, cyclo olefin polymer, polystyrene, polyacrylonitrile, polymethyl methacrylate, polyamide, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalene, or triacetyl cellulose.

10. The luminance adjustment film of claim 1 , wherein the at least one microcapsule contains a solvent in which the photoisomerizable compound is dissolved.

11. The luminance adjustment film of claim 10 , wherein the solvent comprises dimethylformamide, N-methylpyrrolidone, glycerin, polypropylene glycol, or polyethyleneglycol.

12. The luminance adjustment film of claim 1 , wherein the photoisomerizable compound comprises an azobenzene compound, a stilbene compound, a spiropyran compound, or derivatives thereof.

13. The luminance adjustment film of claim 1 , wherein the ultraviolet light has a wavelength to cause a photoisomerization reaction with the photoisomerizable compound.

14. The luminance adjustment film of claim 13 , wherein the wavelength is from about 100 nanometers to about 400 nanometers.

15. The luminance adjustment film of claim 1 , wherein the at least one microcapsule comprises a plurality of microcapsules uniformly distributed in the luminance adjustment film.

16. The luminance adjustment film of claim 15 , wherein a ratio of the plurality of microcapsules to the luminance adjustment film is from about 0.1% to about 90% by weight.

17. The luminance adjustment film of claim 1 , wherein a thickness of the luminance adjustment film is from about 1 micrometer to about 1 centimeter.

18. The luminance adjustment film of claim 1 , wherein an area of the luminance adjustment film is from about 25 square centimeters to about 25,000 square centimeters.

19. An illuminating device comprising:

a visible light source configured to emit visible light;

an ultraviolet light source configured to emit ultraviolet light having an intensity distribution which reflects a luminance distribution of the visible light; and

a luminance adjustment film including at least one microcapsule containing a photoisomerizable compound which selectively decreases luminance of the visible light in reaction to the ultraviolet light.

20. The illuminating device of claim 19 , wherein the visible light source comprises an LED light source.

21. The illuminating device of claim 19 , wherein a maximum intensity of the ultraviolet light is determined so as to prevent the photoisomerizable compound from selectively decreasing the luminance of the visible light in a region where the luminance distribution of the visible light is uniform.

22. A method of manufacturing a luminance adjustment film, the method comprising:

providing at least one microcapsule containing a photoisomerizable compound to selectively decrease luminance of visible light in reaction to ultraviolet light having an intensity distribution which reflects a luminance distribution of the visible light;

providing a transparent resin; and

combining the at least one microcapsule with the transparent resin to produce the luminance adjustment film.

23. A method of manufacturing an illuminating device, the method comprising:

providing a visible light source configured to emit visible light;

providing an ultraviolet light source configured to emit ultraviolet light having an intensity distribution which reflects a luminance distribution of the visible light;

providing at least one microcapsule containing a photoisomerizable compound which selectively decreases luminance of the visible light in reaction to the ultraviolet light;

providing a transparent resin;

combining the at least one microcapsule with the transparent resin to produce a luminance adjustment film; and

combining the luminance adjustment film with the visible light source and the ultraviolet light source to produce the illuminating device.

24. A method of adjusting luminance, the method comprising:

emitting visible light from a visible light source;

emitting ultraviolet light from an ultraviolet light source, the ultraviolet light having an intensity distribution which reflects a luminance distribution of the visible light; and

selectively decreasing luminance of the visible light in reaction to the ultraviolet light by using a photoisomerizable compound.