| 摘要 |
PROBLEM TO BE SOLVED: To provide an imaging lens constituted of four lenses which is compact, and also, wherein various aberrations are sufficiently corrected, to provide an imaging apparatus equipped with the imaging lens, and to provide a personal digital assistant. SOLUTION: The imaging lens includes, in the order starting from the object side: an aperture diaphragm; a first lens of positive refractive power; a second meniscus-shaped lens of negative refractive power with a convex surface directed to the object side; a third lens of positive refractive power; a fourth lens of negative refractive power. Provided that a curvature radius of the object-side surface of the second lens is denoted as r3, the focal length of the whole imaging lens is denoted as f and an Abbe's number of the second lens is denoted as ν2, the imaging lens satisfies conditional inequalities of 0.4<r3/f<0.92 and 15<ν2<27. COPYRIGHT: (C)2010,JPO&INPIT
|
