Patent ID: 6094310
Filing Date: 2000-07-25
Classification: G02B

Abstract:
An eye piece system comprising in order from the object side:a first lens unit having a negative refractive power; anda second lens unit having a positive refractive power, wherein said eyepiece system is configured so as to locate an intermediate image formed by an objective lens system between said first lens unit and said second lens unit, andwherein said second lens unit comprises a first lens component which comprises a positive meniscus lens element having a concave surface on the object side and at least one positive lens element, and has a positive refractive power as a whole,a second lens component which comprises a cemented lens component consisting of a negative lens element and a positive lens element, and has a positive refractive power, and a third lens component which comprises a positive lens element having an object side surface having a strong refractive power and has a positive refractive power,said eyepiece system satisfying the following conditions:-3.0<{(.phi..sub.22a /.nu..sub.22a)/(.phi..sub.22b /.nu..sub.22b)}<-1.010.10<.phi..sub.22 .multidot.f<0.40wherein the reference symbol .phi..sub.22 represents a refractive power of the second lens component disposed in the second lens unit, the reference symbol .phi..sub.22a designates a refractive power of the negative lens element of the cemented lens component used as the second lens component disposed in the second lens unit, the reference symbol .phi..sub.22b denotes a refractive power of the positive lens element of the cemented lens component used as the second lens component disposed in the second lens unit, the reference symbol .nu..sub.22a represents an Abbe's number of the negative lens element of the cemented lens component used as the second lens component disposed in the second lens unit, the reference symbol .nu..sub.22b designates an Abbe's number of the positive lens element of the cemented lens component disposed in the second lens unit and the reference symbol f denotes a focal length of the eyepiece system as a whole.