| 摘要 |
PURPOSE:To obtain an inexpensive, small-sized, and lightweight eyepiece lens with high performance by composing a viewfinder lens of one lens which has a prescribed aspherical plastic lens surface, and meeting specific conditions. CONSTITUTION:A lens for a view finder is composed of one thin lens obtained by making the lens surface of plastics into a prescribed aspherical surface. Then, conditional inequalities 1 and 2 hold when the radius of curvature of a subject- side lens surface is r1, the height of the lens from an optical axis is Y, and the aspherical amount of the aspherical surface from a paraaxial spherical surface is DELTAX (Y). The conditional inequality 1 shows the bending amount of the lens and the astigmatism and distortion of the lens are reduced within the range of the inequality. The conditional inequality 2, on the other hand, specifies the aspherical amount of the lens surface to correct the spherical aberration and comma aberration to obtain high performance. Further, plastics is used, so an inexpensive, lightweight eyepiece lens is obtained. |
