| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a zoom projection lens. <P>SOLUTION: The zoom projection lens comprises a first lens group 100 with negative refractive power and a second lens group 200 with positive refractive power arranged in that order from a projection surface side to an imaging surface side and installed so as to be movable along an optical axis. The first lens group has a first lens 102 with the negative refractive power. The second lens group has a second lens 202 with the positive refractive power, a third lens 204 with the positive refractive power, a fourth lens 206 with the negative refractive power, and a fifth lens 208 with the positive refractive power. The following conditional expression given below is satisfied: 1.9<¾F1/Fw¾<2.1, 0.5<¾F4/Fw¾<0.8, and 0.95<¾F5/Fw¾<1.2. In the expression, F1 is the effective focal distance of the first lens group, F4 is the effective focal distance of the fourth lens, F5 is the effective focal distance of the fifth lens, and Fw is the effective focal distance of the zoom projection lens at a wide angle. <P>COPYRIGHT: (C)2012,JPO&INPIT |
