Patent ID: 7213984
Filing Date: 2007-05-08
Classification: B82Y,G02F,G03B

Abstract:
1. An optical density-changing element comprising: an anode containing a first semiconductor material, the anode further comprising at least one of: a material (a) capable of at least one of donating and accepting an electron, the material (a) undergoing a change in absorption spectrum in the wavelength range of 400 to 700 nm upon at least one of donating and accepting the electron, wherein the anode satisfies the relation of wherein Fba represents a flat band potential of the first semiconductor material and Eo(a) represents an oxidation potential of the material (a); and a material (b) capable of at least one of donating and accepting an electron, the material (b) undergoing substantially no change in absorption spectrum in the wavelength range of 400 to 700 nm upon at least one of donating and accepting the electron, wherein the anode satisfies the relation of wherein Fba represents the flat band potential of the first semiconductor material and Eo(b) represents an oxidation potential of the material (b); and a cathode containing a second semiconductor material, the cathode further comprising at least one of: a material (c) capable of at least one of donating and accepting an electron, the material (c) undergoing the change in absorption spectrum in the wavelength range of 400 to 700 nm upon at least one of donating and accepting the electron, wherein the cathode satisfies the relation of wherein Fbc represents a flat band potential of the second semiconductor material and Er(c) represents a reduction potential of the material (c); and a material (d) capable of at least one of donating and accepting an electron, the material (d) undergoing substantially no change in absorption spectrum in the wavelength range of 400 to 700 nm upon at least one of donating and accepting the electron, wherein the cathode satisfies the relation of wherein Fbc represents the flat band potential of the second semiconductor material and Er(d) represents a reduction potential of the material (d), wherein the optical density-changing material has at least one of (i) the material (a) in the anode, and (ii) the material (c) in the cathode; and the optical density-changing element undergoes the change in optical density in response to a voltage applied between the anode and the cathode.