| 摘要 |
PROBLEM TO BE SOLVED: To provide an imaging lens for near ultraviolet rays capable of sufficiently securing a viewing angle and back focus though it is compact, achieving excellent aberration performance in a near ultraviolet region and easily formed. SOLUTION: In the imaging lens for near ultraviolet rays, a front group FR having negative refractive power and a rear group RE having positive refractive power are disposed in order from an object side. The front group FR has two negative lenses L11 and L12. The surface S1 of the lens L11 is aspherical. The rear group RE has positive lenses L21 to L23 made of glass material, whose Abbe number is≥70, and has a negative lens L31 nearest to an image side. Both of the surface S5 of the lens L21 and the surface S12 of the lens L31 are aspherical. Furthermore, the imaging lens is constituted to satisfy all conditional expressions (1): -3.0<fFR/f<-1.5, (2): 1.7<fRE/f<2.5 and (3): 1.1<Bf/f<1.8. COPYRIGHT: (C)2007,JPO&INPIT
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