| 摘要 |
PROBLEM TO BE SOLVED: To provide an imaging lens for capsule type endoscope, the imaging lens being sufficiently corrected in magnification color aberration and distortion and compact despite a wide-angle lens. SOLUTION: The imaging lens 21 is a lens that images light from a spherical subject 13 onto the imaging surface of a flat imaging element. The imaging lens includes: a first lens L1 of negative refractive power; an aperture stop S6; a second lens L2 of positive refractive power; a third lens L3 of negative refractive power; a fourth lens L4 of positive refractive power; and a fifth lens L5 of positive refractive power. The lenses L1 to L5 and aperture stop S6 composing the imaging lens 21 are shaped and disposed taken into account of the shape of the front end of a capsule 12 and a cover glass 18 of the imaging element 17. They are disposed in the following order from the subject 13 side: the first lens L1, aperture stop S6, second lens L2, third lens L3, fourth lens L4, and fifth lens L5. COPYRIGHT: (C)2010,JPO&INPIT
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