| 摘要 |
PURPOSE: An optical system having a high-magnification viewfinder lens is provided to offset of a plus/minus distortion quantity caused by a first/second lens having a minus/plus refracting function to decrease a distortion quantity, and keep a stroke of the lens for adjusting a standard degree as 2mm to slim a structure. CONSTITUTION: A first lens, equipped in a liquid crystal display(LCD) and designed as non-spherical surface, has a minus refracting function. A second lens, separated and moving as much as a fixed distance from the first lens, has a plus refracting function. When f is a focus distance of the optical system, f1/f2 is a focus distance of the first/second lens, B is a back focal length, T is distance from the first lens surface to the last lens surface, Xa is a sag of a standard spherical surface in a non-spherical surface, and Xo is a sag by the non-spherical surface, a value divided the back focal length(B) by the focus distance of the optical system, is 0.6 or more.
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