Patent ID: 7903515
Filing Date: 2011-03-08
Classification: G11B

Abstract:
1. An optical disc drive having an ability to read data from any of multiple types of optical discs, of which the respective information storage layers are located at mutually different depths as measured from their surface, the drive comprising: a light source for emitting a light beam; a lens for converging the light beam; a photodetector, which receives the light beam that has been reflected from the information storage layer of a given optical disc and outputs a reflected light signal; a servo controller for generating a first type of drive signal to adjust a focus position by changing distances from the lens to the optical disc and a second type of drive signal to adjust tilt of the lens by changing angles defined by the lens with respect to the optical disc; and a signal quality rater for measuring an index value based on the reflected light signal to rate the quality of the reflected light signal, wherein when the drive is loaded with the optical disc, the servo controller changes multiple drive signals of the first and/or second type(s), thereby changing settings to be defined by a combination of the focus position and the tilt, and wherein the signal quality rater measures multiple index values as the settings are changed, and wherein the drive recognizes the type of the given optical disc by the multiple index values and reads data from the optical disc recognized.