Detection of Optical Disk Type
Original Publication Date: 1986-Aug-01
Included in the Prior Art Database: 2005-Mar-09
An optical disk drive is usable with either read-only, write-once, and erasable optical disks. Certain functions of the drive must be tailored for the type disk then in use. A reflectance detector senses the type disk currently in use, and controls these functions of the disk drive accordingly. Media detection is accomplished by using signals received from the disk drive's focus detector while moving the lens toward the disk from a retracted position. As the focusing point of the beam moves toward the disk, the difference signal 11 (F1 - F2) between signals F1 and F2, which are received from each half F1 and F2 of the focus detector, is monitored. Signal 11 will peak just before the focusing point reaches the surfaces of the disk.