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US 2008/0165436 A1Published application
Objective lens
AssigneePENTAX Corporation
InventorsDaisuke KOREEDA, Koichi MARUYAMA, Shuichi TAKEUCHI
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AssigneePENTAX Corporation
InventorsDaisuke KOREEDA, Koichi MARUYAMA, Shuichi TAKEUCHI
Estimating the term…
There is provided an objective lens used for a plurality of types of optical discs having a front surface and a rear surface, each of which includes an inner region and an outer region. The outer region has a surface shape which suppresses a coma caused when a beam used for a first optical disc is incident thereon obliquely with respect to an optical axis of the objective lens. The inner region is configured such that, at a boundary position between the inner region and the outer region, the coma caused when a beam used for a second optical disc is incident on the inner region obliquely at a first angle with respect to the optical axis is less than the coma caused when the beam used for the second optical disc is incident on the outer region obliquely at the first angle with respect to the optical axis. Further, an inclination θ2A of the inner region and an inclination θ2B of the outer region of the rear surface satisfy a condition: −2.5<θ2B−θ2A<0.0 . . . (1).
An objective lens comprising a front surface and a rear surface, at least one surface of the front and rear surfaces including a plurality of regions having different shapes, the at least one surface is configured such that, at each of boundary positions between adjacent ones of the plurality of regions, the adjacent ones of the plurality of regions are continuously connected to each other.
An optical system comprising an objective lens having a front surface and a rear surface, at least one surface of the front and rear surfaces including a plurality of regions having different shapes, the at least one surface is configured such that, at each of boundary positions between adjacent ones of the plurality of regions, the adjacent ones of the plurality of regions are continuously connected to each other.
An objective lens comprising a front surface and a rear surface, at least one surface of the front and rear surfaces including a plurality of regions having different shapes,
An optical system comprising an objective lens having a front surface and a rear surface, at least one surface of the front and rear surfaces including a plurality of regions having different shapes,
Dependencies are inferred from the claim text.