Patent ID: 7755993

Claim:
An optical information recording reproduction device that irradiates a laser beam from an optical pickup to an optical recording medium to form a pit corresponding to information for record on the optical recording medium so as to record information, the device comprising: a reproduction unit configured to reproduce an RF signal obtained from a pit having a length equal to or longer than a diameter of primary light situated in the periphery of a primary dark ring enclosing zero-order light in a central portion of a beam spot formed on the optical recording medium for the optical information recording reproduction device, a differentiation unit configured to perform differential operation of the reproduced RF signal along a time axis of the RF signal so as to obtain pulse signal waveforms generated in correspondence with a front end and a rear end of the beam spot formed on the optical recording medium on the time axis, a storing unit configured to store the pulse signal waveforms generated in correspondence with the front end and the rear end in an absolute value form into a storage medium, a beam profile generation unit configured to combine two pulse signal waveforms stored in the storage medium to generate a beam profile of the beam spot formed on the optical recording medium, and an adjustment unit configured to adjust an optical system incorporated in the optical pickup, and a record laser beam based on the beam profile.