Optical disc recording apparatus with a light beam having a controllable quantity

Claim 1

An optical disc recording apparatus for recording an information signal on an optical disc by use of a recording light beam, said optical disc recording apparatus comprising: a light generating source for generating a recording light beam; a first input terminal supplied with an angular modulated information signal; a second input terminal supplied with a power setting signal indicative of a radial position of the recording light beam on the optical disc; open loop circuit means for controlling an amplitude of the angular modulated information signal responsive to the power setting signal; detecting means for detecting a quantity of light of the recording light beam and for producing a direct current signal within an output detection signal which is obtained by subjecting the detected quantity of light to a photoelectric conversion, said detecting means comprising a light detecting element for detecting the quantity of light of the recording light beam and for producing the detection signal, and direct current amplifier for passing only a direct current component and a low frequency component of the detection signal from said light detecting element; level control means for variably controlling a level of the direct current signal from said detecting means depending on the radial position of the recording light beam on the optical disc and according to a preset characteristic, said level control means comprising a differential amplifier for supplying to said adding means a signal having a level dependent on a level difference between the direct current signal from said second input terminal; and adding means for adding an output direct current signal level of aid level control means and an output signal of said open loop circuit means and for supplying an added signal to said light generating source so as to control a quantity of light of the recording light beam generated thereby, said direct current signal from said detecting means being controlled by a closed loop circuit means comprising said detecting means, said level control means and said adding means.