| 摘要 |
An optical lens for condensing a light emitted from a laser light source on an optical recording medium, the light having a wavelength lambda 1 within a wavelength range from 400 nm to 440 nm, comprises: a light incident side lens surface disposed on a side which the light emitted from the laser light source enters, the light incident side lens surface comprising a peripheral part having an angle theta of 45 degrees or more, where the theta is an angle formed by a normal line at a position on each lens surface and an optical axis; and a first anti-reflection film formed on the light incident side lens surface, the first anti-reflection film having a film thickness which is set so that a wavelength lambda 2 at which a reflectance of the light entering a central part having the angle theta of zero degrees, of the light incident side lens surface at an angle of zero degrees has a local minimum value, satisfies lambda 1<lambda2 and 420 nm<=lambda 2 <=680 nm.
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