Method of determining the monitor sensitivity of, and method and system for controlling a radiation emitting arrangement, and optical recording and/or reproducing apparatus including such a system.

摘要

A method is described which enables automatic determination of the monitor sensitivity of a radiation emitting arrangement (in particular a laser diode and photodiode arrangement), which monitor sensitivity relates a level of a monitor signal (IM) generated by the arrangement to a corresponding optical output level (OL) of the arrangement. The method comprises the steps of: (i) supplying a varying drive signal (IL1,IL2) to the arrangement and measuring the rate of change ( DELTA IM/ DELTA IL) of the monitor signal (IM) with respect to the supplied drive signal (IL); and (ii) combining the measured rate of change with an assumed differential efficiency (k) of the arrangement to determine the monitor sensitivity (OL/IM) of the arrangement. The provision of a control system able to implement such a method can eliminate the need for a factory adjustment in the maufacture of apparatus such as optical recording and/or reproducing apparatus.