| 摘要 |
PROBLEM TO BE SOLVED: To joint crystal materials without a gap without using an adhesive, by forming at least one element out of elements in contact with each other without holding air in between, of a crystal material, and providing the adjacent side to the other element with an amorphous inorganic layer. SOLUTION: The optical member is constituted in such a way that elements 6, 7 come into contact with each other without holding air in between and that the element 7 is formed of crystal material. In this case, the element 7 is provided with an amorphous inorganic layer 70 on the adjacent side to the other element 6. In an optical system constituting a part of projection exposure device for micro-lithography, for instance, and including an achromatic lens, a light source (excimer laser) 1 emits luminous flux 2 with deep ultraviolet wavelength, and lenses 3, 5 and diaphragm 4 expands the luminous flux. The lens 6 formed of quartz glass, and the lens 7 formed of crystal material such as fluoride of CaF2 , MgF2 , NaF, or the like and has a thin quartz layer stuck thereto are positioned without holding air in between and butting to each other to form an achromatic lens. |
