| 摘要 |
The optical reader for compact discs uses a knife edge method for focus control. A laser light source (210) provides a beam of light. A detector receives the light that has been reflected from the surface of a compact disc. An optical system is provided between the laser and the detector. The optical system has first (223, 225) and second (224, 226) surfaces. The second surface reflects a part of the laser beam toward the optical disc and the first surface reflects the beam of light reflected by the optical disc toward the detectors, to allow the optical system to read data from the optical disc. |
