| 摘要 |
PURPOSE: To obtain an fθlens system enabling an ultra-precision measurement, etc., by specifying respective refractive abilities of respective single lenses and distances between principal planes of single-lenses in the fθlens system to be constituted of three sheets of single-lenses. CONSTITUTION: The distance between the principal planes of a first lens 1 and a second lens 2 is defined as e1 and the distance between the principal planes of the second lens 2 and a third lens f3 is defined as e2 . When refractive abilities of respective lenses 1, 2, 3 are respectively defined as k1 , k2 , k3 , the fθsystem is made so as to be k1 <0, k2 >0, k3 >0 and to satisfy the range of -0.08446<=(e1 k1 -e2 k3 )<=-0.03990. Thus, a constant speed scanning performance and the parallelism of outgoing main light beam are improved and, then, this lens system can be used as the light receiving lens system of an ultra-precision laser equipment and can be satisfactorily used in a laser printer and a form generator including a laser scanning micrometer(LSM).
|
