Projection apparatus and projection lens thereof capable of reducing focal length and aberration
First Claim
1. A projection apparatus, comprising:
- a light source module, providing an illumination beam;
a projection lens, disposed between an object side and an image side, and the projection lens comprising;
a reflective unit, disposed between the object side and the image side and having a negative refractive power; and
a refractive unit, disposed between the object side and the reflective unit and having a positive refractive power, and the refractive unit comprising;
a first lens group, disposed between the object side and the reflective unit and comprising at least one cemented lens and an aperture stop, wherein the at least one cemented lens is disposed between the object side and the aperture stop, the first lens group further comprises a first lens, and the at least one cemented lens comprises a second lens, a third lens, and a fourth lens, wherein a refractive index of the third lens is higher than refractive indexes of the second lens and the fourth lens, the third lens has Abbe number between 55 and 90 substantially, and each of the second lens and the fourth lens has Abbe number between 20 and 40 substantially; and
a second lens group, disposed between the first lens group and the reflective unit and comprising at least one aspheric lens; and
a light valve module, converting the illumination beam into an image beam, disposed at the object side, and disposed between the light source module and the projection lens.
1 Assignment
0 Petitions
Accused Products
Abstract
A projection lens including a reflective unit and a refractive unit is provided. The projection lens is disposed between an object side and an image side. The reflective unit is disposed between the object side and the image side and has a negative refractive power. The refractive unit is disposed between the object side and the reflective unit and has a positive refractive power. The refractive unit includes a first lens group and a second lens group. The first lens group is disposed between the object side and the reflective unit and includes at least one cemented lens and an aperture stop. The at least one cemented lens is disposed between the object side and the aperture stop. The second lens group is disposed between the first lens group and the reflective unit and includes at least one aspheric lens. A projection apparatus including the projection lens is also provided.
45 Citations
39 Claims
-
1. A projection apparatus, comprising:
-
a light source module, providing an illumination beam; a projection lens, disposed between an object side and an image side, and the projection lens comprising; a reflective unit, disposed between the object side and the image side and having a negative refractive power; and a refractive unit, disposed between the object side and the reflective unit and having a positive refractive power, and the refractive unit comprising; a first lens group, disposed between the object side and the reflective unit and comprising at least one cemented lens and an aperture stop, wherein the at least one cemented lens is disposed between the object side and the aperture stop, the first lens group further comprises a first lens, and the at least one cemented lens comprises a second lens, a third lens, and a fourth lens, wherein a refractive index of the third lens is higher than refractive indexes of the second lens and the fourth lens, the third lens has Abbe number between 55 and 90 substantially, and each of the second lens and the fourth lens has Abbe number between 20 and 40 substantially; and a second lens group, disposed between the first lens group and the reflective unit and comprising at least one aspheric lens; and a light valve module, converting the illumination beam into an image beam, disposed at the object side, and disposed between the light source module and the projection lens. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
-
-
21. A projection lens, disposed between an object side and an image side, and comprising:
-
a reflective unit, disposed between the object side and the image side and having a negative refractive power; and a refractive unit, disposed between the object side and the reflective unit and having a positive refractive power, and comprising; a first lens group, disposed between the object side and the reflective unit and comprising at least one cemented lens and an aperture stop, wherein the at least one cemented lens is disposed between the object side and the aperture stop, the first lens group further comprises a first lens, and the at least one cemented lens comprises a second lens, a third lens, and a fourth lens, wherein a refractive index of the third lens is higher than refractive indexes of the second lens and the fourth lens, the third lens has Abbe number between 55 and 90 substantially, and each of the second lens and the fourth lens has Abbe number between 20 and 40 substantially; and a second lens group, disposed between the first lens group and the reflective unit and comprising at least one aspheric lens. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
-
Specification