| 摘要 |
A wide-angle lens and a projection device using the same are provided. The wide-angle lens from an image side sequentially comprises a first lens group, a second lens group and a third lens group. The third lens group comprises an aperture stop. The first lens group has a negative refracting power, the second lens group has a positive refracting power, and the third lens group has a positive refracting power. A focal length f1 of the first lens group and a focal length fw of the wide-angle lens satisfy the following conditions: −15 mm<f1<−7.5 mm, and 0.5<|f1/fw|<1.5.
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