Telecentric projection lens

Abstract

Abstract PURPOSE:To easily correct magnification change corresponding to the magnification change due to the error of lens working by nearly conforming the rear side focal point of a front side lens system to the front side focal point of a rear side lens system at a position in the neighborhood of a fourth lens system. CONSTITUTION:The front side lens system LF consisting of first to third lens groups 10-30 arranged sequentially at an image side from an object side, the fourth lens system 40 arranged at the image side of the front side lens group LF and capable of moving in an optical axis direction, and the rear side lens system LR consisting of fifth to seventh lens groups 50-70 arranged sequentially at the image side of the fourth lens system 40 are provided. The rear side focal point of the front side lens system LF is nearly conformed to the front side focal point of the rear side lens system LR at the position in the neighborhood of the fourth lens system 40. Thereby, it is possible to easily correct the magnification change due to the error of the lens working through it is symmetric type telecentric projection lens capable of easily correcting a various kinds of aberration including distortion aberration.

Inventors

• 👤 Naohisa Hayashi
• 👤 尚久 林

Bibliographic Details