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AssigneePanasonic Corporation
InventorsFumitomo YAMASAKI, Yoshiaki Komma, Kanji Wakabayashi, Toshiyasu Tanaka, Katsuhiko Hayashi
Estimating the term…
[Problem] The present invention provides an afocal lens for an optical head that can ensure WD while satisfying NA, the optical head, an optical disc apparatus, a computer, an optical disc player, and an optical disc recorder. [Solution] Using a blue-violet laser beam source with wavelength of about 400 nm, and in an optical head compatible to optical discs having different protective substrate thickness, an afocal lens 105 that expands a diameter of light flux of light from a collimating lens and emits the light as substantially parallel light to an objective lens is provided between the collimating lens 104 and the objective lens 106. The configuration makes it possible to ensure WD while satisfying NA.
An afocal lens provided in an optical head having a collimating lens and an objective lens, the optical head having a diffracted light of n order in each diffracted light of n order and m order (n and m are integers being different to each other) generated from a laser light emitted from a light source onto an information recording surface of a first information recording medium and the diffracted light of m order onto an information recording surface of a second information recording medium,
An optical head comprising:
Dependencies are inferred from the claim text.