Optical recording and reading equipment

Abstract

Disclosed herewith is a data recording and reading equipment capable of reducing laser noise easily. At first, a laser beam source that can reduce the laser noise when reading data from a subject optical disk is obtained. A modulator capable of varying laser attenuation with a voltage is disposed so as to precede the laser, thereby the laser noise when reading data from the optical disk can be reduced without lowering the laser power when in writing.

1 . A data recording and reading equipment, including:
 a laser for emitting a beam, the beam being radiated onto a data recording medium;   a modulator that changes a degree of attenuation of the beam emitted by the laser in accordance with a control voltage applied to the modulator;   a photo-current monitor that detects a photo-current generated at the modulator,   wherein the degree of attenuation is controlled by using an output signal of the photo-current monitor.   
   
   
       2 . A data recording and reading equipment, including:
 a laser for emitting a beam, the beam being radiated onto a data recording medium;   a modulator that changes a degree of attenuation of the beam emitted from the laser in accordance with a control voltage applied to the modulator;   a photo-current monitor that detects a photo-current generated at the modulator,   wherein power of the laser is controller by using an output signal of the photo-current monitor.   
   
   
       3 . The data recording and reading equipment according to  claim 1 , further comprising a laser driver that supplies a modulated signal to the laser so as to emit the beam in accordance with data to be recorded in the recording medium. 
   
   
       4 . The data recording and reading equipment according to  claim 2 ,
 a laser driver that supplies a modulated signal to the laser so as to emit the beam in accordance with data to be recorded in the recording medium.   
   
   
       5 . The data recording and reading equipment according to  claim 3 , wherein said data recording and reading equipment
 controls the power of the laser so as to reduce noise of the laser to a value less than a desired value, and   controls the control voltage applied to the modulator so that beam power of the laser on a surface of the recording medium satisfies a value determined by a standard for the recording medium.   
   
   
       6 . The data recording and reading equipment according to  claim 4 , wherein said data recording and reading equipment
 controls the power of the laser so as to reduce noise of the laser to a value less than a desired value, and   controls the control voltage applied to the modulator so that beam power of the laser on a surface of the recording medium satisfies a value determined by a standard for the recording medium.