| 摘要 |
PURPOSE:To obtain a condenser lens which has an excellently compensated curvature of field by specifying the conditions of a lens group of six elements having positive, positive, negative, positive, positive, and negative refracting power successively from an object side. CONSTITUTION:This lens system has six-element constitution of the 1st positive lens, the 2nd positive lens, the 3rd biconcave lens, the 4th biconvex lens, the 5th positive lens having a large-curvature surface on the object side, and the 6th negative lens having a large-curvature surface on the image side successively from the object side. This lens system meets requirements shown by inequalities I -IV, wherein (f) is the focal length of the whole system and ri is the radius of curvature of the (i)th surface. |
