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. 01, 2003
Filed:
Apr. 05, 2001
Jiro Yoshinari, Tokyo, JP;
Takuya Tsukagoshi, Tokyo, JP;
Hideki Hirata, Tokyo, JP;
Naoki Hayashida, Tokyo, JP;
Tokuyuki Honda, Mountain View, CA (US);
Mark E. McDonald, Milpitas, CA (US);
Michael V. Morelli, San Jose, CA (US);
Andrew J. Daiber, Palo Alto, CA (US);
Sanjoy Ghose, Scotts Valley, CA (US);
Lambertus Hesselink, Atherton, CA (US);
Shunichi Nishimura, Milpitas, CA (US);
Sergei Sochava, Sunnyvale, CA (US);
Other;
Abstract
An optical information medium comprising at least two data layers for bearing recorded information, and a servo layer for bearing tracking servo, information which is independently formed from the data layers; wherein the medium is used with a recording or reading system wherein a data beam for recording or reading the data in the data layer and a servo beam for reading the tracking servo information in the servo layer are used, and the servo layer is read by the servo beam that had passed through the data layer; and a filter layer is disposed between the data layer and the servo layer, and the filter layer exhibits higher absorption to the data beam than to the servo beam.