Optical scanning arrangement for maintaining constant the light output of a laser beam or the laser current

摘要

An optical scanning arrangement in which a laser beam is generated by a source with a monitor diode. The laser beam is focused on an optical recording medium. A summing amplifier has a first input connected to a source of a periodic signal. This source of periodic signal is also connected to a first input of a multiplier. The multiplier has an output connected to a second input of the summing amplifier. This summing amplifier has an output connected to a positioning device in the focusing circuit for the laser beam. This focusing circuit has an actual value which is supplied to a third input of the summing amplifier. The multiplier receives a laser controlling signal on a second input for the purpose of maintaining the light output of the laser beam at a constant level.