Patent ID: 7164631
Filing Date: 2007-01-16
Classification: G11B

Abstract:
1. An information recording apparatus for writing information onto an information storage medium using a light beam emitted from a light source, comprising: a first detection unit for detecting a power of a light beam emitted from said light source; a second detection unit for detecting a non-track condition and an in-focus condition of said light beam relative to said information storage medium; a first generation unit for generating a detection signal indicative of a variation in power of the light beam on the basis of a detection signal output from said first detection unit; a second generation unit for generating a tracking error signal on the basis of a detection signal output from said second detection unit; a third generation unit for generating a focus error signal on the basis of a detection signal output from said second detection unit; a first control unit for adjusting the power of the light beam emitted from said light source on the basis of the detection signal generated by said first generation unit; a second control unit for performing tracking servo on the basis of the tracking error signal generated by said second generation unit; and a third control unit for performing focus servo on the basis of the focus error signal generated by said third generation unit, and at least one delay device delaying a sample and hold signal which is in sync with information to be written and is to be supplied to a focus and tracking servo system formed from said second and third generation units and said second and third control units, wherein said first control unit samples and holds the detection signal generated by said first generation unit, in sync with a timing delayed by a time corresponding to a delay time of said first generation unit, and adjusts the power of said light beam on the basis of the detection signal held, said second control unit samples and holds the tracking error signal generated by said second generation unit, in sync with a timing delayed by a time corresponding to a delay time of said second generation unit, and performs said tracking servo on the basis of the tracking error signal held, and said third control unit samples and holds the focus error signal generated by said third generation unit, in sync with a timing delayed by a time corresponding to a delay time of said third generation unit, and performs said focus servo on the basis of the focus error signal held.