Optical information recording and reproducing apparatus with amplitude limitation of a detected signal in a write operation mode

Claim 1

An optical information recording and reproducing apparatus having a single semiconductor laser for recording information bits on an optical recording film with laser light responsive to a drive current modulated by an information signal during a write operation mode and for radiating constant readout laser light onto said recording film to reproduce signals recorded on the recording film during a read operation mode, comprising: means for detecting light reflected from said optical recording film and for converting the detected reflected light to an electric signal; a binary coding circuit including means for detecting a positive envelope signal and a negative envelope signal with respect to said electric signal, means for producing a threshold signal in accordance with said positive and negative envelope signals, and means for comparing said electric signal with said threshold signal so as to convert said electric signal to a binary signal; and amplitude limiting means for limiting the amplitude of said electric signal during the write operation mode, said amplitude limiting means being disposed at a stage preceding said binary coding circuit.