Projection lens

Patent metadata

Field	Value
Publication number	US-2016266358-A1
Application number	US-201514779756-A
Country	US
Kind code	A1
Filing date	Jan 30, 2015
Priority date	Jul 22, 2014
Publication date	Sep 15, 2016
Grant date	—

Abstract

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.

First claim

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, and
3< f 3/ 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.

2 . The projection lens according to claim 1 , wherein each of the first lens and the second lens has two sides both being in an aspheric shape, the third lens has two sides both being in a spherical shape.

3 . The projection lens according to claim 2 , wherein the third lens is made of a glass material.

4 . (canceled)

5 . The projection lens according to claim 1 , wherein the projection lens meets the following formula:
0.2<( R 3+ R 4)/( R 3 −R 4)<1.2, wherein R3 represents a curvature radius of an image side of the second lens, R4 represents a curvature radius of the object side of the second lens.

6 . The projection lens according to claim 5 , wherein the projection lens meets the following formula:
0.2<( R 5+ R 6)/( R 5− R 6)<1.2,
wherein R5 represents a curvature radius of an image side of the third lens, R6 represents a curvature radius of the object side of the third lens.

7 . The projection lens according to claim 1 , wherein an object side of the first lens is convex.

8 . The projection lens according to claim 7 , wherein the image side of the second lens is convex.

9 . The projection lens according to claim 8 , wherein the image side of the third lens is convex.

10 . The projection lens according to claim 1 , wherein the reflective optical device enabling the light path to be bended is a reflecting prism or a reflecting plane mirror.

11 . The lens assembly according to claim 2 , wherein an object side of the first lens is convex.

12 . The lens assembly according to claim 3 , wherein an object side of the first lens is convex.

13 . The lens assembly according to claim 5 , wherein an object side of the first lens is convex.

14 . The lens assembly according to claim 6 , wherein an object side of the first lens is convex.

15 . The lens assembly according to claim 2 , wherein the reflective optical device enabling the light path to be bended is a reflecting prism or a reflecting plane mirror.

16 . The lens assembly according to claim 3 , wherein the reflective optical device enabling the light path to be bended is a reflecting prism or a reflecting plane mirror.

17 . The lens assembly according to claim 5 , wherein the reflective optical device enabling the light path to be bended is a reflecting prism or a reflecting plane mirror.

18 . The lens assembly according to claim 6 , wherein the reflective optical device enabling the light path to be bended is a reflecting prism or a reflecting plane mirror.

19 . The lens assembly according to claim 7 , wherein the reflective optical device enabling the light path to be bended is a reflecting prism or a reflecting plane mirror.

20 . The lens assembly according to claim 8 , wherein the reflective optical device enabling the light path to be bended is a reflecting prism or a reflecting plane mirror.

Assignees

• Zhejiang Sunny Optics Co Ltd

Inventors

• Huang Lin
• Dai Fujian

Classifications

• G02B13/0065 Primary

  having a beam-folding prism or mirror · CPC title

• G02B13/16

  for use in conjunction with image converters or intensifiers {, or for use with projectors, e.g. objectives for projection TV} · CPC title

• G02B13/0035

  having three lenses · CPC title

• G02B27/0025

  for optical correction, e.g. distorsion, aberration · CPC title

• G02B9/12

  having three components only · CPC title