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:
Mar. 25, 2008
Filed:
Dec. 02, 2004
Ying-feng Huang, Lucao Township, TW;
Ying-Feng Huang, Lucao Township, TW;
Mediatek Inc., , TW;
Abstract
A method for discriminating between different types of optical discs is intended to apply to an optical storage device with a pick-up head having three beams. A main beam push-pull signal and a sub-beam push-pull signal, both acquired by means of the photo-detector of the pick-up head, are superposed on each other to have an additive push-pull signal, whereas, on subtraction, the difference between the main beam push-pull signal and the sub-beam push-pull signal generates a differential push-pull signal. If the peak-to-peak voltage of the differential push-pull signal is greater than that of the additive push-pull signal, it is judged that the light spots derived from the sub-beams and the main beam of the three beams respectively fall on two contiguous lands and a groove therebetween on an optical disc inside the optical storage device. Also, if the peak-to-peak voltage of the differential push-pull signal is smaller than that of the additive push-pull signal, it is judged that the light spots derived from the sub-beams and the main beam separately fall on three contiguous grooves on the optical disc respectively.