Optimum reproduction laser power based on amplitude level of information signal

An optical information apparatus for reproducing an information signal recorded on an optical recording medium by irradiating a laser light modulated by an information signal on the optical information recording medium to obtain a reproduced signal, comprising a laser power control circuit controlling power of said laser light to an optimum value during reproduction to a value based on a swing amplitude level from bottom to top of said information signal upon reproduction wherein said laser power control circuit comprises a peak-hold means for detecting and holding a peak amplitude value at a bottom level of said reproduced signal, an adding means for adding the peak amplitude value at a bottom level detected by said peak-hold means and said reproduced information signal, said peak-hold means holding an added out-put signal by said adding means, thereby making a DC signal proportional to the swing amplitude level from bottom to top of said reproduced signal to be detected.

An optical information reproducing method for reproducing an information signal recorded on an optical recording medium by irradiating a laser light modulated by an information signal on the optical information recording medium to obtain a reproduced signal,

• comprising the steps of, during reproduction, controlling power of said laser light to a value based on a swing amplitude level from bottom to top of said information signal upon reproduction, and outputting a difference between a swing amplitude level from bottom to top of said information signal upon reproduction and a target level value as an operating signal that controls the laser light.

An optical information reproducing method for reproducing a high frequency information signal recorded on an optical recording medium by irradiating a laser light modulated by an information signal on the optical information recording medium to obtain a reproduced signal,

• comprising the steps of:
• during reproduction, controlling power of said laser light to an optimum value during reproduction to a value based on the swing amplitude level from bottom to top of said information signal upon reproduction, detecting a peak amplitude value at a bottom level of said reproduced signal by holding its peak value, adding a bottom peak value detected by holding its peak and said reproduced signal, and holding a peak of said added output signal, thereby making a DC signal proportional to the swing level from bottom to top of said reproduced signal to be detected.