The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 22, 2007
Filed:
Aug. 04, 2003
Nobuyoshi Mori, Hachioji, JP;
Katsuya Yagi, Hachioji, JP;
Bernardus Hendrikus Wilhelmus Hendriks, Eindhoven, NL;
Johannes Joseph Hubertina Barbara Schleipen, Eindhoven, NL;
Marco Andreas Jacobus Van As, Eindhoven, NL;
Nobuyoshi Mori, Hachioji, JP;
Katsuya Yagi, Hachioji, JP;
Bernardus Hendrikus Wilhelmus Hendriks, Eindhoven, NL;
Johannes Joseph Hubertina Barbara Schleipen, Eindhoven, NL;
Marco Andreas Jacobus Van As, Eindhoven, NL;
Koninklijke Philips Electronics N. V., Eindhoven, NL;
Abstract
An optical scanning device () for scanning an information layer () of an optical record carrier (), the device () comprising a radiation source () for generating a radiation beam () and an objective system () for converging the radiation beam on the information layer, the information layer being covered by a transparent layer () of thickness td and refractive index nd. The objective system comprises a lens having a protection device projecting away from the lens towards the optical record carrier such that the distance between the protection device and the optical record carrier is less than the free working distance. The lens satisfies the condition: where D is the entrance pupil diameter, FWD is the free working distance, and D, FWD, t and td are all expressed in millimeters and where FWD+td/nd<0.51.