Vari-focal lens

Abstract

Abstract PURPOSE:To obtain a compact lens which have aberrations compensated excellently by providing the lens with the 1st positive lens group and the 2nd negative lens group successively from an object side and adding at least one distributed index lens which meets specific requirements to at least one of lens groups. CONSTITUTION:An optical system has the 1st- the 4th lens groups A, B, C, and D and when the power is varied, the gap between the 1st lens group A and the 2nd lens group B is varied. Then, at least one of the lens groups have at least one distributed index lens having a refractive index distribution N(h) shown by an equation I. In the equation, No is the refractive index on the optical axis and (h) is the radial distance frm the optical axis, and inequalities II and III hold, where phi is the refractive power of the lens group including the distributed index lens and K is a coefficient (K=+1 when the curved surface is convex and K=-1 when concave) expressing the shape of the curved surface having larger curvature between both surfaces of the distributed index lens.

Inventors

• 👤 Nozomi Kitagishi
• 👤 望 北岸
• 👤 Hiroki Nakayama
• 👤 博喜 中山
• 👤 Shigeyuki Suda
• 👤 須田　繁幸
• 👤 Jun Hattori
• 👤 純 服部
• 👤 Akinaga Horiuchi
• 👤 昭永 堀内

Bibliographic Details