| 摘要 |
PROBLEM TO BE SOLVED: To provide an unifocal lens for visible light and near-infrared light which is small-sized and has larger diameter, by which aberration correction is satisfactorily carried out in a visible light wavelength region (about 400 to 700mm) and a near-infrared light wavelength region (700 to 1000mm) and which can be suitably used for a surveillance camera, a CCTV, a video camera or the like. SOLUTION: The unifocal lens for visible light and near-infrared light is constituted of a front lens group having negative refracting power and a rear lens group having positive refracting power while holding a diaphragm therebetween. The rear lens group is composed of at least four lenses including a junction lens of a positive lens and a negative lens and has brightness of 1.05 to 1.15 F number. COPYRIGHT: (C)2005,JPO&NCIPI
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