| 摘要 |
An zoom projection lens includes, in this order from the screen-side to the SLM-side thereof, a negative lens group and a positive lens group, and satisfies: −2<Φ1/Φ2<−0.5, −2<EFL1/EFL(W)<−1.5, 1.5<EFL2/EFL(W)<1.75, −1.2<EFL1/EFL(T)<−1, 0.8<EFL2/EFL(T)<1.2, 0.5<EFL(W)/BFL(W)<0.6, 0.68<EFL(T)/BFL(T)<0.75, 6.2<TTL(W)/EFL(W)<6.5, and 3.5<TTL(T)/EFL(T)<3.6; where Φ1 and Φ2 represent refractive powers of the negative lens group and the positive lens group respectively, EFL(W), EFL(T), EFL1 and EFL2 represent effective focal lengths of the projection lens in a wide-angle state and in a telephoto state, the negative lens group, and the positive lens group respectively, TTL(W) and TTL(T) represent overall lengths of the projection lens in the wide-angle state and in the telephoto state respectively, and BFL(W) and BFL(T) represent rear focal lengths of the projection lens in the wide-angle state and in the telephoto state respectively.
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