Infrared transmission film, optical film, antireflection film, optical component, optical system and image pickup device

[0075] Example 1

[0076] In Example 1, zinc oxide films containing bismuth oxide as an additive were formed on both surfaces of the substrate by the magnetron sputtering method. Hereinafter, the steps of film formation will be specifically described.

[0077] First, a target, which is a film-forming raw material, and a base material are arranged to face each other in a magnetron sputtering apparatus. As a film-forming raw material, a sintered target of zinc oxide was used. At this time, tablet pieces of bismuth oxide were uniformly arranged on the target. As the base material, chalcogenide glass (IRG206 manufactured by Hubei Xinhua Guang Information Materials Co., Ltd.) was used.

[0078]Next, the entire inside of the device is evacuated. Subsequently, the pressure in the device reached 3×10 -4 At Pa, 20 SCCM of argon gas (standard ml / min, 1 atmosphere (25° C.)) was injected, and then 5 SCCM of oxygen gas was injected. The exhaust speed was adjusted so that the pressure

[0080] Example 2

[0081] In Example 2, a zinc oxide film containing bismuth oxide as an additive was produced in the same manner as in Example 1, except that the content of bismuth oxide was adjusted to 0.7% by mass.

[0082] Example 3

[0083] In Example 3, a zinc oxide film containing bismuth oxide as an additive was produced in the same manner as in Example 1, except that the content of bismuth oxide was adjusted to 14.7% by mass.