| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce deviation of a spot position formed on a light receiving element caused by variation of surrounding temperature. <P>SOLUTION: A base 17, a collimator lens holder 21, and a condenser lens holder 22 are manufactured by materials satisfying conditions indicated in a formula 1 : (α1-αb)/(α2-αb)×R1/R2×sinb/sina=1 where: α1 is collimator lens holder 21; α2 is condenser lens holder 22; ab is linear expansion coefficient of a material by which the base 17 is manufactured; R1 is a distance from a center of the collimator lens 12 to the base 17; R2 is a distance from a center of the collimator lens 12 to the base 17; F1 is an effective focal distance in the collimator lens; F2 is an effective focal distance in the condenser lens 15; a is 1/2 angle of a bottom part of a first V shape groove 17b; and b is 1/2 angle of a bottom part of a second V shape groove 17c. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
