Photocatalyst excitation apparatus

A photocatalyst excitation apparatus comprising:

• a substrate;
• a light guide layer formed on the substrate;
• a light source for emitting excitation light for a photocatalyst towards the light guide layer;
• and
• a photocatalyst layer formed on the light guide layer, the excitation light emitted from the light source passing through the light guide layer and leakage light from the light guide layer activating the photocatalyst layer,
• wherein the wavelength of the excitation light emitted from the light source is a wavelength near the absorption edge corresponding to the band gap of the photocatalyst layer, and
• wherein the light source is placed on the photocatalyst layer, and the excitation light for the photocatalyst emitted from the light source is incident on the light guide layer through a prism placed in contiguity with the light source on the photocatalyst layer.

A photocatalyst excitation apparatus comprising:

• a substrate;
• a light guide layer formed on the substrate;
• a light source for emitting excitation light for a photocatalyst towards the light guide layer;
• and
• a photocatalyst layer formed on the light guide layer, the excitation light emitted from the light source passing through the light guide layer and leakage light from the light guide layer activating the photocatalyst layer,
• wherein the wavelength of the excitation light emitted from the light source is a wavelength near the absorption edge corresponding to the band gap of the photocatalyst layer, and
• wherein the light source comes into close contact with the end face of the substrate with a prism provided therebetween, the excitation light emitted from the light source is incident on the light guide layer through the prism.

A photocatalyst excitation apparatus comprising:

• a substrate;
• a light guide layer formed on the substrate;
• a light source for emitting excitation light for a photocatalyst towards the light guide layer;
• and
• a photocatalyst layer formed on the light guide layer, the excitation light emitted from the light source passing through the light guide layer and leakage light from the light guide layer activating the photocatalyst layer,
• wherein a first buffer layer transmitting the excitation light and having a refractive index which is lower than that of the light guide layer is disposed between the substrate and the light guide layer.

A photocatalyst excitation apparatus comprising:

• a substrate;
• a light guide layer formed on the substrate;
• a light source for emitting excitation light for a photocatalyst towards the light guide layer;
• and
• a photocatalyst layer formed on the light guide layer, the excitation light emitted from the light source passing through the light guide layer and leakage light from the light guide layer activating the photocatalyst layer,
• wherein a buffer layer transmitting the excitation light and comprising an nonoxidizing material is disposed between the light guide layer and the photocatalyst layer.

A photocatalyst excitation apparatus comprising:

• a substrate;
• a light guide layer formed on the substrate;
• a light source for emitting excitation light for a photocatalyst towards the light guide layer;
• and
• a photocatalyst layer formed on the light guide layer, the excitation light emitted from the light source passing through the light guide layer and leakage light from the light guide layer activating the photocatalyst layer,
• wherein a buffer layer transmitting the excitation light, having a thickness which is smaller than or the same as the wavelength of the excitation light for the photocatalyst, and having a refractive index which is lower than that of the light guide layer is disposed between the light guide layer and the photocatalyst layer.