Fitzpatrick, Cella, Harper & Scinto
Optical element with substrate containing fluorite as main ingredient, and method and apparatus for producing the optical element
 A film formation method of forming at least one layered film on a substrate containing fluorite as a main ingredient by using a film formation apparatus which emits electrons or ions, which comprises the step of forming, as a first layered film counted from the side of the substrate, a film having a thickness of 30 nm or less and comprising at least one selected from the group consisting of SiO.sub.2, BeO, MgO, and MgF.sub.2. 
Canon Kabushika Kaisha
G
G02B
inventional
Ryuji Minoru Yasuyuki Hidehiro Kenji
Biro Otani Suzuki Kanazawa Ando