| 摘要 |
Provided is a projection lens including: a first lens, a reflective optical device, a second lens and a third lens from an image side of the projection lens to an object side of the projection lens in turn. The first lens is of a negative focal power, an image side of the first lens is concave; the reflective optical device enables light to be bended; the second lens is of a positive focal power, an object side of the second lens is convex; the third lens is of a positive focal power, an object side of the third lens is convex. A diaphragm is arranged between first lens and second lens, the projection lens meets: 0.4<ImgH/D<0.7, wherein ImgH equals to a half-length of an object diagonal, D represents a vertical height from the image side of the first lens to a center axis perpendicular to an object. |
| 主权项 |
1. A projection lens, comprising a first lens, a reflective optical device, a second lens and a third lens from an image side of the projection lens to an object side of the projection lens in turn, wherein
the first lens is of a negative focal power, an image side of the first lens is concave; the reflective optical device enables a light path to be bended; the second lens is of a positive focal power, an object side of the second lens is convex; and the third lens is of a positive focal power, an object side of the third lens is convex, wherein a diaphragm is arranged between the first lens and the second lens, the projection lens meets the following formulas:
0.4<ImgH/D<0.7, and3<f3/f<6, wherein ImgH equals to a half-length of an object diagonal, D represents a vertical height from the image side of the first lens to a center axis perpendicular to an object, f3 represents a focal length of the third lens, and f represents a focal length of the lens assembly. |
