| 摘要 |
PROBLEM TO BE SOLVED: To provide a small-sized image pickup lens system capable of realizing miniaturization and excellent image quality. SOLUTION: The small-sized image pickup lens system comprises an aperture diaphragm and a meniscus lens in which a concave face toward the object side and a convex face toward the image face are formed curvedly, in order from the object side to the image face. In the meniscus lens, the face toward the object side is aspheric, the face toward the image face is constituted of diffraction grating and the system satisfies the conditional relation (1); 0.1<R2/R1<0.5. Therein, R1 is radius of curvature of apex on the surface of the meniscus lens close to the object side and R2 is radius of curvature of apex on the surface of the meniscus lens close to the image face. Since the small-sized image pickup lens system utilizes a single range of diffraction/refraction, the cost is reduced and an excellent image quality may be provided. COPYRIGHT: (C)2006,JPO&NCIPI
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