Patent ID: 6055057
Filing Date: 2000-04-25
Classification: G01D,H04N

Abstract:
A scanning apparatus having a scanning light beam which moves along a scan path for writing onto a media, comprising:a detector disposed in said scan path;a first amplifier having a negative input, a positive input and an output, the output of the detector being connected to the negative input of said first amplifier;a second amplifier having a negative input, a positive input and an output, the output of said second amplifier being connected to the positive input of said first amplifier, said second amplifier providing an output to said first amplifier such that said first amplifier is forced to a predetermined value when no signal is being produced by the photo diode; anda time delay circuit provided between the output of said second amplifier and the positive input of said first amplifier for delaying the signal from said second amplifier to said positive input of said first amplifier.