Projection lens and projection system having same
AssigneeHon Hai Precision Industry Co., Ltd.
InventorsKuang-Ju Wang, Chun-Hsiang Huang
Life of this patent
Estimating the term…
Abstract
A projection lens includes, in the order from a large conjugate side to a small conjugate side thereof, a negative lens group having a negative refractive power and a positive lens group having a positive refractive power. The positive lens group includes, in the order from the large conjugate side to the small conjugate side of the projection lens, a front sub-group and a rear sub-group each having a positive refractive power. The projection lens satisfies the formulas: −1.35<F1/F<−0.35 and 3<F24/F<5, where F1, F24, and F correspondingly represent the effective focal lengths of the negative lens group, the rear sub-group, and the projection lens.
Claims18
A projection lens comprising, in the order from a large conjugate side to a small conjugate side thereof, a negative lens group having a negative refractive power and a positive lens group having a positive refractive power, the positive lens group comprising, in the order from the large conjugate side to the small conjugate side of the projection lens, a front sub-group and a rear sub-group each having a positive refractive power, wherein the projection lens satisfies the formulas:
- −1.35<F1/F<−0.35, 3<F24/F<5, and BF/F>4.5, where F1, F24, F, and BF correspondingly represent the effective focal lengths of the negative lens group, the rear sub-group, the projection lens, and the rear focal length of the projection lens.
A projection system comprising:
- a body;
- a projection lens, mounted in the body, comprising, in the order from a large conjugate side to a small conjugate side thereof:
- a negative lens group having a negative refractive power;
- and
- a positive lens group having a negative refractive power and comprising, in the order from the large conjugate side to the small conjugate side of the projection lens:
- a front sub-group having a positive refractive power;
- and
- a rear sub-group having a positive refractive power, wherein the projection lens satisfies the formulas:
- −1.35<F1/F<−0.35, 3<F24/F<5, and BF/F>4.5, where F1, F24, F, and BF correspondingly represent the effective focal lengths of the negative lens group, the rear sub-group, the projection lens, and the rear focal length of the projection lens;
- and
- a spatial light modulator placed at the small conjugate side of the projection lens.
Dependencies are inferred from the claim text.