Optical recording medium discriminating apparatus using laser beams of different wavelengths

摘要

In an optical recording and reproducing apparatus, two light sources such as a laser diode of different wavelengths from each other are provided, and photosensors receive the light emitted by the light sources and reflected by the optical recording medium. Before recording or reproduction is started, the type of optical recording medium having a different wavelength dependent reflectance is discriminated. Because two wavelengths are used, the difference of the outputs is large, and the type of the optical recording medium is discriminated reliably according to the outputs of the photosensors. Then, the operation of the apparatus is stabilized according to the type of the optical recording medium by optimizing the laser power, the gain of the controller, the revolution number of the medium or the like.