Optical pickup system for reading optical disks of different thicknesses

Abstract

An optical pickup system for reading information stored on a first or a second optical disk, each of the optical disks having a different thickness and selectively loaded on a disk tray, is provided with a light source for generating a first or a second light beam depending on the optical disk selectively loaded, each of the first and the second light beams having a different wavelength from each other, .lambda..sub.1, .lambda..sub.2, a knife edge, an optical device including a first and a second parts, an objective lens and a detector. In the above system, if one of the optical disks is selected to be loaded on a disk tray, the light source selects a light beam from the first and the second light beams based on the thickness of the selected optical disk. The knife edge reflects a portion of the selected light beam to the corresponding part of the optical device and the objective lens focuses the portion of the selected light beam transmitted through the selected optical disk, wherein the corresponding part of the optical device is capable of transmitting the selected light beam. The light beam reflected from the selected optical disk is converged on the detector and the corresponding part of the optical device, thereby allowing the optical pickup system to read the information off the selectively loaded optical disk.