| 摘要 |
An objective lens is configured of a first crown-glass lens and a second flint-glass lens, whereby it can exhibit substantially identical optical properties at a plurality of recording/reproducing light source wavelengths, particularly, in both 650 nm and 405 nm wavelength bands. Also, by maximizing the difference in glass transition point between the first and second lenses, one of the first and second lenses having a higher glass transition point is molded first, to allow that first molded lens to serve as a mold tool for molding the other lens. This dispenses with the steps of aligning and adhesive bonding the two lenses, whereby this objective lens can be used at a plurality of wavelengths as a single objective lens, and thus an information recording/reproducing apparatus can be of a simple configuration.
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