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:
Jun. 18, 2002
Filed:
Feb. 14, 2000
Masataka Izawa, Tsurugashima, JP;
Pioneer Corporation, Tokyo-to, JP;
Abstract
The light beam emitted by the light source is irradiated on the information storage medium via the optical system. The reflected light beam is irradiated by the light guide path element. Then by the grating, a part of the light beam is input-coupled with the waveguide layer while the remaining part is transmitted and received by the light receiving portion below. An adjustment is made such that the coupling efficiency to the waveguide layer by the first grating pattern is maximized when the relative distance between the information storage medium and the optical system increases, and the coupling efficiency to the waveguide layer by the second grating pattern is maximized when the relative distance between the information storage medium and the optical system decreases. In the light receiving portion, divided according to the respective grating patterns, the received light quantity becomes minimum when the respective coupling efficiencies are maximum.