| 摘要 |
PURPOSE:To optimize a use efficiency to an optical scan of a laser light and to use a cylindrical lens with small power by making a direction orthogonal to the joint surface of a semiconductor laser for light source and a main scanning direction correspond to each other in parallel, and providing a 1/2 wavelength plate in a laser optical path. CONSTITUTION:A laser light L' radiated from a semiconductor laser 10 is converted to a parallel luminous flux by a collimating lens 11, and its luminous flux section becomes an elliptical shape in which a Y direction is a long axis direction. The laser luminous flux transmits through a 1/2 wavelength plate 12, holds a luminous flux section shape, nd the electric field vibrating direction rotates from the X direction to the Y direction. Subsequently, it transmits through an aperture 13 and a cylindrical lens 4', is made on a hologram lattice disk 1 through a plane mirror 5, deflected periodically by the rotation of the disk 1, and executes a main scan to a surface to be scanned 9. This laser light has an elliptical shape already in a state converted to a luminous flux, therefore, it will do that a power of the lens 4' is smaller than a power of a cylindrical lens 4. Also, the effective use efficiency of a laser light to a optical scan is secured by an effect of the 1/2 wavelength plate 12. |
