| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an optical scanner that uses a resin-made lens for both optical systems in the front and the rear of a deflecting means, that extends the latitude of a lens shape, and that can secure superior optical characteristics even with a difference of wavelength between light emitting points. <P>SOLUTION: The optical scanner is characterized in that a first optical system has a lens made of resin which has the diffraction surface while a second optical system has an optical element made of resin, that a plurality of laser beams emitted from the same light source pass through the same optical element, and that, whereΔλis the wavelength variance between laser beams in one light source;Δm'1,Δm'2 are the changes of a main scanning beam waist position which are caused respectively by the power change of a refraction part and by the power change of a diffraction part at the time the light source wavelength of the first optical system is increased by 1 nm;Δm'3 is the change of a main scanning beam waist position which is caused by the power change at the time the light source wavelength of the second optical system is increased by 1 nm; and Wm is the depth of a main scanning beam diameter; a conditional expression ofΔλ<Wm/¾Δm'1+Δm'2+Δm'3¾ (A) is satisfied. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
