| 摘要 |
<p>PROBLEM TO BE SOLVED: To achieve a four-lens-group-type zoom lens for projection that achieves both a long back focus and a short focal distance at the wide angle end.SOLUTION: There is provided a zoom lens for projection used in an image display device that projects an image for projection displayed on an image display surface of an image display element on a projection target surface to enlarge and display the image, and having a four-lens-group configuration having first to fourth lens groups arranged from the enlargement side toward the reduction side, where the first lens group G1 and the second lens group G2 have a negative refractive power; and the third lens group G3 has a positive refractive power; and the distance from a lens surface on the most reduction side of the fourth lens group G4 to the image display surface Bf and the focal distance at the wide angle end Fw satisfy the condition (1): 1.9<Bf/Fw.</p> |
