Abstract: An optical lens, comprising: an enlarging side and a shrinking side, between the enlarging side and the shrinking side sequentially having a first group lens, a light diaphragm, and a second group lens, wherein the light diaphragm is for separating the first group lens and the second group lens; the first group lens having multiple lenses, and the second lens is an aspheric lens; the second group lens having at least four lenses, wherein at least one lens is an aspheric lens and a positive diopter lens is an aspheric lens; the first group lens and the second group lens having two set of doublet lens.

Abstract: An optical lens includes a first lens group and a second lens group. The first lens group is disposed between a magnified side and a minified side and has a negative refractive power. The second lens group is disposed between the first lens group and the minified side and has a positive refractive power. The optical lens is capable of forming an image at the magnified side. 0.52>F/H>0.46, where F is an effective focal length, and H is an image height.

Abstract: A lens including a first lens group and a second lens group is provided. The first lens group is disposed between a magnified side and a minified side. The second lens group is disposed between the first lens group and the minified side. The lens includes six or less lens elements, and at least four of the six or less lens elements are aspheric lenses. A field of view of the lens is in a range between 100 degrees and 165 degrees, and the second lens group has at least one spherical lens.

Abstract: An optical lens includes a first lens group with a negative refractive power, a second lens group with a positive refractive power, and an aperture stop disposed between the first lens group and the second lens group. The second lens group is disposed between the first lens group and the second side. The optical lens satisfies the conditions: 2.1<D1/D3<3.0 and 1.9<D1/DL<3.2, where D1 is a diameter of a surface of the first lens facing the first side, D3 is a diameter of a surface of the third lens facing the first side, DL is a diameter of a surface of a last lens facing the second side, and the last lens is nearest the second side as compared with any other lens of the optical lens.

Abstract: An optical lens includes a first lens group with a negative refractive power, an aperture stop, and a second lens group with a positive refractive power. The first lens group includes a first aspheric lens and a second aspheric lens. The optical lens satisfies the conditions: 3.5>RT1>2.5 and 3.5>RT2>2.6, where RT1 is a ratio of a maximum axial thickness to a minimum axial thickness within a clear aperture of the first aspheric lens, and RT2 is a ratio of a maximum axial thickness to a minimum axial thickness within a clear aperture of the second aspheric lens.

Abstract: An optical lens includes a first lens group with a negative refractive power, a second lens group with a positive refractive power, and an aperture stop disposed between the first lens group and the second lens group. The second lens group is disposed between the first lens group and the second side. The optical lens satisfies the conditions: 2.1<D1/D3<3.0 and 1.9<D1/DL<3.2, where D1 is a diameter of a surface of the first lens facing the first side, D3 is a diameter of a surface of the third lens facing the first side, DL is a diameter of a surface of a last lens facing the second side, and the last lens is nearest the second side as compared with any other lens of the optical lens.

Abstract: A lens including a first lens group and a second lens group is provided. The first lens group is disposed between a magnified side and a minified side. The second lens group is disposed between the first lens group and the minified side. The lens includes six or less lens elements, and at least four of the six or less lens elements are aspheric lenses. A field of view of the lens is in a range between 100 degrees and 165 degrees, and the second lens group has at least one spherical lens.

Abstract: An optical lens includes a first lens group and a second lens group. The first lens group is disposed between a magnified side and a minified side and has a negative refractive power. The second lens group is disposed between the first lens group and the minified side and has a positive refractive power. The optical lens is capable of forming an image at the magnified side. 0.52>F/H>0.46, where F is an effective focal length, and H is an image height.

Abstract: An optical lens includes a first lens group with a negative refractive power, an aperture stop, and a second lens group with a positive refractive power. The first lens group includes a first aspheric lens and a second aspheric lens. The optical lens satisfies the conditions: 3.5>RT1>2.5 and 3.5>RT2>2.6, where RT1 is a ratio of a maximum axial thickness to a minimum axial thickness within a clear aperture of the first aspheric lens, and RT2 is a ratio of a maximum axial thickness to a minimum axial thickness within a clear aperture of the second aspheric lens.