A projection system includes a first optical system and a second optical system disposed on an enlargement side of the first optical system. The first optical system includes a first lens group having positive power, a second lens group disposed on the enlargement side of the first lens group and having negative power, and an optical path deflector disposed between the first lens group and the second lens group. The second optical system includes a reflection member having a concave reflection surface. The second lens group includes three aspherical lenses. Conditional Expression (1) below is satisfied,

0.25<|F|×FNO/Ymax<0.5  (1)

where F represents the focal length of the entirety of the projection system, FNO represents the F number of the projection system, and Ymax represents a maximum image height in a reduction-side conjugate plane.

A projection system includes a first optical system and a second optical system disposed on an enlargement side of the first optical system. The first optical system includes a first lens group having positive power, a second lens group disposed on the enlargement side of the first lens group and having negative power, and an optical path deflector disposed between the first lens group and the second lens group. The second optical system includes a reflection member having a concave reflection surface. The second lens group includes three aspherical lenses. Conditional Expression (1) below is satisfied,

0.25<|F|×FNO/Ymax<0.5  (1)

where F represents the focal length of the entirety of the projection system, FNO represents the F number of the projection system, and Ymax represents a maximum image height in a reduction-side conjugate plane.

An optical lens assembly, including a first lens element, a second lens element, a third lens element, a fourth lens element, and a fifth lens element sequentially along an optical axis from a first side to a second side, is provided. The optical lens assembly satisfies the conditional expression of D34/D12≥2.600. Furthermore, other optical lens assemblies are also provided.

An imaging lens includes first, second, third, fourth, fifth and six lens elements arranged in order from an object side to an image side along an optical axis. Each of the lens element has a thickness along the optical axis. Two of thicknesses of the first to the fourth lens elements along the optical axis are the thickest and the second thickest among the abovementioned six lens elements, respectively.

The present disclosure discloses an optical imaging lens assembly including, sequentially from an object side to an image side along an optical axis, a first lens having refractive power; a second lens having refractive power; a third lens having negative refractive power; a fourth lens having refractive power and a convex object-side surface; a fifth lens having refractive power and a concave object-side surface; a sixth lens having refractive power; a seventh lens having refractive power; and an eighth lens having refractive power. A total effective focal length f of the optical imaging lens assembly and half of a maximal field-of-view Semi-FOV of the optical imaging lens assembly satisfy: f*tan(Semi-FOV)>5.5 mm. A total effective focal length f of the optical imaging lens assembly and an effective focal length f1 of the first lens satisfy: 0.5<f/f1<1.5.

The present disclosure discloses an optical imaging lens group including, sequentially from an object side to an image side along an optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens having reactive power. The first lens has positive refractive power, a convex object-side surface, and a concave image-side surface. A total effective focal length f of the optical imaging lens group and half of a maximal field-of-view Semi-FOV of the optical imaging lens group satisfy: f*tan(Semi-FOV)>7.5 mm. A distance TTL along the optical axis from the object-side surface of the first lens to an imaging plane of the optical imaging lens group and half of a diagonal length ImgH of an effective pixel area on the imaging plane of the optical imaging lens group satisfy: TTL/ImgH<1.3.

The present disclosure discloses an optical imaging lens group including, sequentially from an object side to an image side along an optical axis, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens having reactive power. The first lens has positive refractive power, a convex object-side surface, and a concave image-side surface. A total effective focal length f of the optical imaging lens group and half of a maximal field-of-view Semi-FOV of the optical imaging lens group satisfy: f*tan(Semi-FOV)>7.5 mm. A distance TTL along the optical axis from the object-side surface of the first lens to an imaging plane of the optical imaging lens group and half of a diagonal length ImgH of an effective pixel area on the imaging plane of the optical imaging lens group satisfy: TTL/ImgH<1.3.

A near-eye display apparatus is disclosed. The near-eye display apparatus includes a lens and an optical path folding assembly. The lens is configured to receive incident light of a first image, which is projected by a micro-display, and shape the first image; the lens includes a primary optical axis and a first lens face and a second lens face which are opposed in a first direction where the primary optical axis of the lens is positioned, and both the first lens face and the second lens face are aspheric surfaces; and the optical path folding assembly is configured to receive light of the first image shaped by the lens and fold an optical path from the lens to an exit pupil of the near-eye display apparatus. By adopting the bi-aspherical lens, image quality of the near-eye display apparatus can be improved and the volume can be reduced.

There is provided a projection optical system capable of projecting an image formed on an image forming unit on a projection plane, which has an extremely short projection distance and a small size.

There is provided a projection optical system capable of projecting an image formed on an image forming unit on a projection plane, which has an extremely short projection distance and a small size.