Wide-angle lens and projection device using the same
AssigneeQisda Corporation
InventorMing-Kuen Lin
Life of this patent
Estimating the term…
Abstract
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.
Claims16
A wide-angle lens disposed in a projection device, wherein the wide-angle lens from an image side sequentially comprises:
- a first lens group having a negative refracting power;
- a second lens group having a positive refracting power;
- and
- a third lens group comprising an aperture stop and having a positive refracting power;
- wherein, 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.
A projection device, comprising:
- a wide-angle lens from an image side sequentially comprising:
- a first lens group having a negative refracting power;
- a second lens group having a positive refracting power;
- and
- a third lens group comprising an aperture stop and having a positive refracting power;
- and
- an optical element, wherein the wide-angle lens is located between the image and the optical element;
- wherein, 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.
Dependencies are inferred from the claim text.