| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an objective lens capable of providing an optical signal having balance between contrast and a total transmitted light quantity. <P>SOLUTION: The objective lens is provided with a first optical surface 3 facing a light source side, a first anti-reflection film 4 positioned in the surface of the first optical surface 3 and constituted of a plurality of layers, a second optical surface 5 facing an optical information recording medium, and a second anti-reflection prevention film 6 positioned in the surface of the second optical surface and constituted of a plurality of layers. The first anti-reflection film 4 includes a wavelength λ1 at which reflectance to light vertically made incident on an optical axis is smallest within the range of a wavelength area of λ to λ+20%, the second anti-reflection film 6 includes a wavelength λ2 at which a reflectance to light vertically made incident on the optical axis is smallest within the range of a wavelength area of λ to λ+20%, and the wavelengths λ1 and λ2 satisfy the relationship of λ<λ2<λ1<λ+20%. <P>COPYRIGHT: (C)2009,JPO&INPIT |
