LASER RECORDING DEVICE

摘要

PURPOSE:To change the diameter of a spot of a laser beam on a recording medium with a simple constitution by arranging a diaphragm means in the optical system of a laser recording device and changing the stopping variable of the diaphragm means in accordance with recording magnification. CONSTITUTION:The diaphragm 7 arranged in the optical path between a collimater lens 2 and a rotary polyhedral mirror 4 is constituted of an optical diaphragm or the like to be used for normal camera e.g. and its stopping variable is determined by a magnification selecting lever 8 in accordance with the magnification of an image. The diameter (d) of the laser beam spot is found out from the focal distance (f) of an ftheta lens and the diameter D of a beam made incident on the ftheta lens on the basis of d=4lambdaf/pi. Consequently, the diameter (d) of the laser beam spot on the recording medium can be changed by changing stopping variable of the diaphragm 7 to change the diameter D of the beam made incident on the ftheta lens.