| 摘要 |
PURPOSE: To prevent damages by thermal shock and collision of highspeed water drops by constituting the optical element of a base layer containing a first material and a coating layer containing refractory oxide which covers the base and forming the coating layer in such a manner that it has a first region containing the material of the base layer and refractory oxide and a second region containing refractory oxide which covers the first region. CONSTITUTION: This element has a base layer 12 of a first material selected from gallium arsenide, gallium phosphate, cadmium telluride. zinc sulfide, etc., and a coating layer 11 containing the material of the base layer 12 and refractory oxide. The coating layer 11 has a first part 16 adjacent to the base layer 12. In the first part 16, the compsn. changes in the thickness direction and the proportion of the base layer material decreases with the thickness of the first part. The coating layer 11 has a second part 18 which covers the first part 16, and the second part 18 consists of a refractory oxide. Thereby, the optical element has high transmittance for 8 to 12μm wavelength and high oxidation resistance and thermal shock resistance and is hardly damaged by collision of water drops. |
