The present invention relates to a reflective eyepiece optical system and a head-mounted near-to-eye display device. The system includes: a first lens group, a first optical element and a second lens group for transmitting and reflecting light from a miniature image displayer; the second lens group includes an optical reflection surface, and the optical reflection surface is the optical surface farthest from a human eye viewing side in the second lens group; the optical reflection surface is concave to human eyes; the first optical element reflects the light refracted by the first lens group to the second lens group, and then transmits the light refracted, reflected and again refracted by the second lens group to the human eyes.

A camera device according to one embodiment of the present invention comprises: a base; a first lens assembly which is disposed in the base and includes a first lens group and a first lens support unit to which the first lens group is fixed; a second lens assembly which is disposed in the base and includes a second lens group and a second lens support unit to which the second lens group is fixed; and a driving unit for moving the second lens assembly, wherein a first stopper member and a second stopper member are formed on the inner wall of the second lens support unit and spaced apart from each other by a distance that is greater than the height of the first lens assembly along the movement direction of the second lens support unit, the first lens assembly is accommodated between the first stopper member and the second stopper member in the second lens support unit, and the second lens assembly moves alongside the first lens assembly within the base.

A storage medium stores correction data for obtaining a correction amount for correcting image data, obtained from an image formed by a lens apparatus, with respect to a distribution of a light amount in the image, wherein the correction data includes a coefficient of an n-th order polynomial (where n is a non-negative integer) with respect to an image height h, the coefficient corresponding to a state of the lens apparatus. The coefficient satisfies a first inequality
−0.15≤dD′(h)−dDlens(h)≤1.98, where dDlens(h) represents a change amount of the light amount at the image height h per an increase amount dh of the image height h, and dD′(h) represents a change amount of an inverse of a value of the n-th order polynomial at the image height h per the increase amount dh.

A mid-wave infrared (MWIR) discrete zoom lens for use with remote surveillance and identification having a dual focal length of 9 and 6.39 inches and F #2.8 and F #2, respectively. In one case, a full field of view is about 30.8 degrees for a 9 inch focal length configuration and about 43 degrees for a 6.39 inch focal length configuration. The lens is corrected for monochromatic and chromatic aberrations over the wavelength range 5100 nm-3300 nm. The focal plane may constitute a pixel array consisting of MWIR sensitive material (e.g. InSb, HgCdTe, nBn, SLS, etc.) for use in high-resolution, wide-area imaging applications.

The present disclosure discloses a telephoto optical imaging system and zoom camera apparatus. The telephoto optical imaging system includes, sequentially from an object side to an image side along an optical axis, a first lens having positive refractive power, a second lens having negative refractive power, an optical path turning prism, and a triangular prism. A total effective focal length F1 of the telephoto optical imaging system may satisfy F1>40 mm. The zoom camera apparatus includes the telephoto optical imaging system and a short-focus optical imaging system arranged in parallel with the telephoto optical imaging system. A total effective focal length F1 of the telephoto optical imaging system and a total effective focal length F2 of the short-focus optical imaging system satisfy F1/F2>5.

In an optical system which includes a positive lens Gp and in which a distance on an optical axis from an object-side lens surface of a lens disposed closest to an object side to an image surface is shorter than a focal length of an entire system, an arrangement and a material of the positive lens Gp, and an arrangement of a focus unit are set appropriately.

A projection system that can be incorporated in a projector includes a first lens unit that makes a screen (enlargement-side image formation plane), which is located on the enlargement-side, conjugate with an intermediate image and a second lens unit that makes the intermediate image conjugate with a reduction-side image formation plane, which is located on the reduction side. The first lens unit has positive power, and the second lens unit has negative power. A second-lens-unit intermediate-image-side first lens, which is provided in the second lens unit and closest to the intermediate image, has positive power. The following expression is satisfied:

−0.3≦fU1/fU2<0

where fU1 denotes the focal length of the first lens unit, and fU2 denotes the focal length of the second lens unit.

A compact bi-telecentric device includes refractive lenses and takes in light from a grid of emitters at the object plane and images them to a grid of receivers. It provides the capacity to combine multiple wavelengths of emitters at the object plane into a single receiver. The device is quite compact, less than 25 mm in length from object to image, and having a maximum diameter for any element of less than 4 mm. The device includes four optical lens elements, three of which have a positive focal length and one of which has a negative focal length. The device includes at least one diffractive optical element. The lens elements are separated into two distinct groups which each have positive optical power, separated by an aperture stop which may or may not be enabled by a physical surface. A diffractive element enables wavelength division multiplexing and compensates for distortion from the bi-telecentric device.

A head up display system, including: a display screen used for displaying an image; an imaging lens arranged on a light exit side of the display screen and used for imaging an image displayed on the display screen; and a curved reflecting mirror arranged on the side of the imaging lens facing away from the display screen and used for receiving imaging light of the imaging lens and reflecting said light to the position where human eyes are located. Relative positions of the display screen and the imaging lens are fixed, and the imaging lens and the curved reflecting mirror adopt a separate structure.

The 1-2nd lens group is divided into three lens groups which move when focusing is performed during the magnification change. Even in a case in which the second optical group is formed of one mirror, it is possible for a primary image to contain appropriate aberration and to hereby reduce aberration of an image which is finally projected onto a screen through the second optical group.