| 摘要 |
PURPOSE:To obviate the deviation of a beam which scans on an x-axis to a y-axis direction even when a rotary polyhedral mirror inclines by using the rotary polyhedral mirror disposed with plural sets of mirrors consisting of 2 pieces having lines of intersection on the plane intersecting orthogonally with a revolving shaft on the same circumference centering at the revolving shaft. CONSTITUTION:A rotary polyhedral mirror 3 is constituted of 8 sets consisting of 2 pieces (a), (b) intersecting with each other at an angle theta. Incident light 2 is reflected from one of two pieces a set of the mirrors to the other and is made into exit light 2'. When the mirror 3 is viewed from the side surface, the angle that the light 2 and the light 2' assume is 0 deg., that is, parallel when, for example, the angle theta of intersection is 90 deg.; therefore, if the parallel luminous fluxes are converged with an imaging optical system 6, the incident angle is immobile even when the mirror 3 is mounted to the shaft 1 with inclination by the angle theta (because the light source device does not move), whereby the scanning in the direction vertical to the plane of the figure is performed without deviation of the converging point O of the parallel luminous flux. |
