Variable light condensing lens apparatus and solar cell apparatus

1. A variable light condensing apparatus comprising:

a volume including a hydrophilic photocatalyst located on a surface thereof; and

a liquid provided within the volume in contact with the hydrophilic photocatalyst,

wherein the hydrophilic photocatalyst is configured to exhibit higher hydrophilicity when irradiated with light having a predetermined wavelength compared to when not irradiated with the light, and

wherein the liquid is configured to form a condensing lens when the hydrophilic photocatalyst is irradiated with the light at less than a predetermined luminous flux density.

2. The variable light condensing apparatus of claim 1 , wherein the hydrophilic photocatalyst is located on a surface of a translucent support, and wherein the translucent support forms at least a portion of the surface of the volume.

3. The variable light condensing apparatus of claim 1 , wherein the liquid is translucent.

4. The variable light condensing apparatus of claim 1 , wherein the liquid does not form a condensing lens in response to irradiation with light at the predetermined luminous flux density or higher.

5. The variable light condensing apparatus of claim 1 , further comprising a second liquid having a lighter specific gravity than that of the liquid, wherein the second liquid is in contact with the liquid and has a non-affinity with the liquid.

6. The variable light condensing apparatus of claim 5 , wherein the second liquid comprises at least one of an oil or a non-polar solvent.

7. The variable light condensing apparatus of claim 1 , wherein the light has a wavelength in an ultraviolet region, and wherein the hydrophilic photocatalyst is responsive to light having a wavelength in the ultraviolet region.

8. The variable light condensing apparatus of claim 1 , wherein the light has a wavelength in a visible region, and wherein the hydrophilic photocatalyst is responsive to light having a wavelength in the visible region.

9. The variable light condensing apparatus of claim 1 , wherein the hydrophilic photocatalyst comprises at least one of TiO 2 , BaTiO 3 , SrTiO 3 , BaZrO 3 , SrZrO 3 or Ge 3 N 4 .

10. The variable light condensing apparatus of claim 1 , wherein volume comprises a bottom surface and side wall surfaces, and wherein the hydrophilic photocatalyst is formed on the bottom surface and the side wall surfaces.

11. A solar cell apparatus comprising:

a solar cell element;

one or more electrodes connected to the solar cell element; and

a variable light condensing apparatus configured to direct light to the solar cell element, the variable light condensing apparatus comprising:

a volume including a hydrophilic photocatalyst located on a surface thereof; and

a liquid provided within the volume in contact with the hydrophilic photocatalyst,

wherein the hydrophilic photocatalyst is configured to exhibit higher hydrophilicity when irradiated with light having a predetermined wavelength compared to when not irradiated with the light, and

wherein the liquid is configured to form a condensing lens when the hydrophilic photocatalyst is irradiated with the light at less than a predetermined luminous flux density.

12. The solar cell apparatus of claim 11 , further comprising a plurality of solar cell elements, and wherein the variable light condensing apparatus is formed over the plurality of solar cell elements and is configured to direct light to each of the plurality of solar cell elements.

13. A method of forming a variable light condensing apparatus, the method comprising:

applying a hydrophilic photocatalyst to a surface of a volume, wherein the hydrophilic photocatalyst is configured to exhibit higher hydrophilicity when irradiated with light having a predetermined wavelength compared to when not irradiated with the light; and

providing a liquid within the volume and in contact with the hydrophilic photocatalyst, wherein the liquid is configured to form a condensing lens when the hydrophilic photocatalyst is irradiated with the light at less than a predetermined luminous flux density.

14. The method of claim 13 , wherein the applying a hydrophilic photocatalyst to a surface of a volume comprises applying the hydrophilic photocatalyst to a surface of a translucent support, wherein the translucent support forms at least a portion of the surface of the volume, and wherein the liquid is translucent.

15. The method of claim 13 , wherein the liquid is configured to not form a condensing lens in response to irradiation with light at the predetermined luminous flux density or higher.

16. The method of claim 13 , further comprising providing a second liquid within the volume in contact with the liquid, wherein the second liquid has a lighter specific gravity than that of the liquid, and wherein the second liquid comprises at least one of an oil or a non-polar solvent.

17. The method of claim 13 , wherein the hydrophilic photocatalyst comprises at least one of TiO 2 , BaTiO 3 , SrTiO 3 , BaZrO 3 , SrZrO 3 or Ge 3 N 4 .

18. The method of claim 13 , further comprising locating the volume over a solar cell element, wherein the variable light condensing apparatus is configured to direct light to the solar cell element.

19. The method of claim 18 , further comprising locating the volume over a plurality of solar cell elements, and wherein the variable light condensing apparatus is configured to direct light to each of the plurality of solar cell elements.

20. The method of claim 13 , wherein the applying a hydrophilic photocatalyst to a surface of a volume comprises:

applying an application liquid to the surface of the volume to form a film on the surface of the volume, wherein the application liquid includes the hydrophilic photocatalyst; and

treating the film.

21. The method of claim 20 , wherein the treating the film comprises at least one of heat-treating the film or drying the film.

22. A method comprising:

receiving light at a surface of a hydrophilic photocatalyst, wherein the hydrophilic photocatalyst is in contact with a liquid contained within a volume, and wherein the hydrophilic photocatalyst is configured to exhibit higher hydrophilicity when irradiated with light having a predetermined wavelength compared to when not irradiated with the light; and

forming a condensing lens from the liquid in response to the receiving light at the surface of the hydrophilic photocatalyst, wherein the received light exhibits less than a predetermined luminous flux density.

23. The method of claim 22 , wherein the hydrophilic photocatalyst is located on a surface of a translucent support, wherein the translucent support forms at least a portion of the surface of the volume, and wherein the liquid is translucent.

24. The method of claim 22 , wherein the volume comprises a second liquid in contact with the liquid, wherein the second liquid has a lighter specific gravity than that of the liquid, and wherein the second liquid comprises at least one of an oil or a non-polar solvent.

25. The method of claim 22 , wherein the light has a wavelength in an ultraviolet region, and wherein the hydrophilic photocatalyst is responsive to light having a wavelength in the ultraviolet region.

26. The method of claim 22 , wherein the light has a wavelength in a visible region, and wherein the hydrophilic photocatalyst is responsive to light having a wavelength in the visible region.

27. The method of claim 22 , further comprising directing the received light to a solar cell element via the condensing lens.

28. The method of claim 22 , further comprising directing the received light to a plurality of solar cell elements via the condensing lens.