Patent ID: 6747804
Filing Date: 2004-06-08
Classification: G02B

Abstract:
An objective lens system for microscope comprising, in order from an object side:a first lens unit including a plurality of cemented lens components and converging light coming from an object, a second lens unit including a negative lens component having a concave surface of strong optical power on the image side, and a third lens unit including a cemented doublet composed of a negative lens element having a concave surface on the object side and a positive lens element, wherein said objective lens system satisfies the following conditions (1) through (3): 1.65&lE;nd&lE;1.8â€ƒâ€ƒ(1) 25&lE;&ngr;d&lE;41â€ƒâ€ƒ(2) T360&gE;0.5â€ƒâ€ƒ(3) wherein nd and &ngr;d are refractive index at d-line and abbe's number of the positive lens element in the third lens unit, respectively, T360 is an internal transmittance except for a reflection loss at 360 nm for a 10 mm thickness of the material forming the positive lens element in the third lens unit.