| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a reading lens excellent in performance having a bright F-number of about 4.2 and a wide half view angle of about 23 degrees. <P>SOLUTION: The reading lens forms a reduced size image of an original image on an imaging surface of an imaging element and includes, in order from an object side, a positive first group, a negative second group, a negative third group, a positive fourth group, and a positive fifth group, and a diaphragm is provided between the second group and the third group. The first group is composed of a positive first lens L1, the second group is composed of a positive second lens L2 and a negative third lens L3 cemented to the image side of the positive second lens L2, the third group is composed of a negative fourth lens L4, the fourth group is composed of a positive fifth lens L5, and the fifth group is composed of a positive sixth lens L6 and a negative seventh lens L7 cemented to the image side of the positive sixth lens L6. Thus, the reading lens is composed of seven lenses of five groups. The reading lens satisfies conditions set properly. <P>COPYRIGHT: (C)2012,JPO&INPIT |
