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:
Apr. 27, 2010
Filed:
Oct. 17, 2006
Masaki Arai, Shizuoka, JP;
Masaki Arai, Shizuoka, JP;
Sony Corporation, Tokyo, JP;
Abstract
An optical pickup including: a light source; a diffractive element; an objective lens; and a photodetector, wherein the diffractive element has first to fourth areas provided with a predetermined periodic structure in each of the areas, the second and third areas have phases of the periodic structures of the second and third areas varied at an angle of about 180 degrees, the first area has a phase of the periodic structure in the first area varied from a phase of the periodic structure in the second area at an angle of about 180 degrees, and the fourth area has a phase of the periodic structure in the fourth area varied from a phase of the periodic structure in the third area at an angle of about 180 degrees. The optical pickup can obtain an excellent tracking error signal and improved amplitude when the objective lens is displaced.