| 摘要 |
<P>PROBLEM TO BE SOLVED: To correct the color aberration of an optical system caused by the wavelength fluctuation or variance of a light source, and to provide a sufficient condensing spot in a short wavelength region (350 to 450 nm) optical system. <P>SOLUTION: The coupling optical system 2 is provided with a lens part 2a making a luminous flux emitted from a light source 1 roughly parallel to an optical axis, and the diffraction part 2b of a first means for correcting the color aberration of the entire optical system caused by the wavelength fluctuation of the light source 1 is reduced by the color aberration correction of the diffraction part. Spherical aberration caused by the wavelength variance of the light source 1 is reduced by setting a distance between a first surface in which he luminous flux from the light source 1 is made incident on the coupling optical system 2 and the light source 1 by a second means. Thus, the aberration is reduced in the diffraction surface provided as the first means in the optical system in the case of the wavelength fluctuation, and the aberration is reduced in a wide short wavelength range by the second means for adjusting the distance from the light source in the optical axis direction of the coupling optical system in the case of the wavelength variance. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
