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:
Oct. 26, 1999
Filed:
Oct. 08, 1997
Applicant:
Inventors:
Jau-Jiu Ju, Hsinchu Hsien, TW;
Shin-Ter Tsai, Taipei, TW;
Pei-Yih Liu, Changhua Hsien, TW;
Tsung-Ming Yang, Chilung, TW;
Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369112 ; 369 58 ; 369110 ; 369 94 ; 369 4424 ;
Abstract
A two-wavelength laser pick-up head used for accessing DVD, CD, CD-R and CD-E systems. The two-wavelength laser pick-up head includes a shorter wavelength laser optical path for reading the data from a DVD system, and a longer wavelength laser optical path for reading the data from a CD or CD-R system. The above two optical paths use the same collimator and the same objective lens. There is a compensator lens which is used in the longer wavelength laser optical path for correcting the spherical aberration due to the thick substrate of the CD or CD-R.