F-theta lens system

Abstract

Abstract PURPOSE:To compensate aberrations of an f.theta lens system consisting of three elements in three groups even when its field angle is about 50 deg. and includes a lens moving to and away from an incident pupil position. CONSTITUTION:The f.theta lens system consists of three elements in three groups, i.e. the 1st negative lens, the 2nd positive meniscus lens, and the 3rd biconvex positive lens arranged in front of a lens system successively from the incident pupil side. Inequalities (1)-(6) hold, where ni, vi, and fi are the refractive index of the (i) the lens to specific wavelength, Abbe number and focal length of the (i)th lens, (f) is the focal length of the entire lens system, and ri and li are the radius of curvature of the (i)th surface and the (i)th air gap.

Inventors

• 👤 Takehiro Nakae
• 👤 武弘 中枝
• 👤 Ryota Ogawa
• 👤 良太 小川
• 👤 Yasunori Arai
• 👤 新井　保則

Bibliographic Details