| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a light collecting optical system having a small focal spot and a long focal depth. <P>SOLUTION: A light collecting optical system for collecting laser light generated by a laser light source at a predetermined focal distance includes first optical means having a light collecting function and second optical means having a spherical aberration generating function, and is configured to generate spherical aberrations. Also, designing the system to satisfy equations (a) to (d) below generates the third and fifth order spherical aberrations. (a) ¾Z<SB POS="POST">8</SB>¾≥0.1λ or ¾Z<SB POS="POST">15</SB>¾≥0.05λ, (b) Z<SB POS="POST">8</SB>/Z<SB POS="POST">15</SB>≥3 or Z<SB POS="POST">8</SB>/Z<SB POS="POST">15</SB><1, (c) ¾Z<SB POS="POST">8</SB>¾<1.4λ, (d) ¾Z<SB POS="POST">15</SB>¾<0.5λ, where λ is wavelength, Z<SB POS="POST">8</SB>is the eighth coefficient of the Zernike fringe polynomial for spherical aberration and corresponds to the third order spherical aberration, and Z<SB POS="POST">15</SB>is the fifteenth coefficient of the Zernike fringe polynomial for spherical aberration and corresponds to the fifth order spherical aberration. <P>COPYRIGHT: (C)2013,JPO&INPIT |
