| 摘要 |
PURPOSE:To contrive the improvement of durability by providing a titanium dioxide layer whose thickness is 1-100nm, and an alumina layer whose film thickness is within a range of lambda/5<nd<lambda/4 at the time when the film thickness is denoted as (nd) on a first layer and a third layer, and a second layer by a spattering method, respectively. CONSTITUTION:To a first layer and a third layer, a titanium dioxide layer is brought to spattering to thickness of 10nm by 8X10<-4> torr spatter gas pressure, 5cc/min argon gas flow rate, 0.5cc/min oxygen gas flow rate, and 300w spatter output. Subsequently, to a second layer, an alumina layer whose film thickness is within a range of lambda/5<nd<lambda/4 at the time when the film thickness is denoted as (nd) is brought to spattering under the same condition, and an antireflection coating is formed. The transmittivity in this rutile single crystal is as shown in a graph, and being different from that which is vapor-deposited by a vapor deposition method, there is no difference in the film structure in the center part and the peripheral part of the formed film. In such a way, the improvement of durability can be contrived. |
