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AssigneeKoninklijke Philips Electronics N.V.
InventorsBernardus Hendrikus Wilhelmus Hendriks, Jorrit Ernst De Vries
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An optical scanning device for scanning of a first, second and third type of optical record carrier with radiation of a first wavelength λ1, a second wavelength λ2 and a third wavelength λ3, respectively, where the three wavelengths are substantially different. The device comprises: a radiation source for emitting a beam of said radiation, an objective system for converging the beam on a selected one of the optical record carriers, and a phase structure arranged in the path of the beam, the phase structure comprising a plurality of phase elements of different heights, forming a non-periodic stepped profile of optical paths in the beam, and is characterised in that the stepped profile substantially approximates a flat wavefront at the first wavelength λ1, a spherical aberration wavefront at the second wavelength λ2, and a flat or spherical aberration wavefront at the third wavelength λ3.
An optical scanning device for scanning of a first, second and third type of optical record carrier with radiation of a first wavelength λ1, a second wavelength λ2 and a third wavelength λ3, respectively, the three wavelengths being substantially different, the device comprising:
A lens for use in an optical device for scanning a first, second and third type of optical record carrier with a beam of radiation of a first wavelength λ1, a second wavelength λ2 and a third wavelength λ3, respectively, the three wavelengths being substantially different, the lens comprising:
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