Patent ID: 6115338
Filing Date: 2000-09-05
Classification: G11B

Abstract:
A method for adjusting the light emitting power of a laser diode adapted for emitting a laser beam within an optical storage apparatus that includes a laser diode for emitting a laser beam, a light emission current source circuit for supplying a drive current according to a plurality of powers to said laser diode, an automatic power control unit for controlling light emitting power of said laser diode to a specified target power, a monitor photosensitive device for receiving a part of the laser beam of said laser diode and for outputting a photosensitive current, a subtraction current source circuit for subtracting a specified subtraction current corresponding to a difference between a specified light emitting power and said target power from said photosensitive current and for converting said difference into a monitor current and for feeding back said monitor current to said automatic power control unit, a measuring unit for monitoring to read the monitor current derived from said subtraction current source circuit as a power measurement value, and a light emission adjustment processing unit, said light emission adjustment processing unit performing said method comprising the steps of:sequentially instructing said light emission current source to supply drive currents for light emission of predetermined test powers at two points;driving said laser diode for light emission with said drive currents;instructing said subtraction current source circuit of specified subtraction currents corresponding to said test powers at two points;measuring each test power from said measuring unit; andobtaining a relation between the instruction values sent to said light emission current source circuit and said subtraction current source circuit in an arbitrary power by linear approximation on the basis of results of said measurement.