| 摘要 |
PURPOSE:To easily measure dynamic beam profile of a light beam by scanning a light shielding plate having an opening portion by light beams, and displaying differential output signals after the photoelectric conversion thereof onto a waveform measuring instrument. CONSTITUTION:Laser light L1 outputted from a recording laser diode 2 is reflected by a galvanometer mirror 6 through a collimator 4 to be projected through an ftheta lens 8 in an approximately orthogonal direction to a opening portion 54 of a light shielding plate 56. The light L1 passing through the opening portion 54 is photoelectrically converted by a converter 58 and introduced into a current voltage converting circuit 90. Thereafter, a voltage signal generated from the circuit 90 is amplified by an amplifier 91, differentiated by a differentiation circuit 92, and taken out as a waveform signal proportional to the shape or form of the light beam. At this time, the offset is removed simultaneously. The waveform signal is guided to an oscilloscope 94. Therefore, if the oscilloscope 94 is operated for a suitable time, the waveform proportional to the form of the light beam is indicated on the tube surface of the oscilloscope 94. |
