| 摘要 |
PROBLEM TO BE SOLVED: To lessen the adverse influence of heat generation on an optical means by segmenting a deflector from another region within a scanning optical device to form an opening for incidence and an opening for reflection. SOLUTION: A shielding upper cap to be assembled onto a supporting frame 1 consists mainly of a partition wall 202 and shielding member 203 forming a proper block by falling from an upper plate and has a hollow groove over nearly the entire area of the circumference. In such a case, the opening for incidence of a light beam to a polygon mirror 5 and the one opening in common use as the opening for reflection of the light beam through the polygon mirror 5 are formed by proximity or contact of the partition wall 102 and partition wall 202 disposed on the supporting frame 1 side. The light beam 8 from a laser beam source 3 emitted in correspondence to recording data in the manner described above passes a colimater lens and a first cylindrical lens and after the light beam is deflected by the polygon mirror 5, the optical path before arriving at a recording medium through an fθlens, a second cylindrical lens and a slit is assured. |
