The zoom lens consists of, in order from an object side, a first lens group that has a positive refractive power, a second lens group that has a negative refractive power, a middle group that includes one or more lens groups, and a final lens group. The middle group has a positive refractive power as a whole throughout an entire zoom range. During zooming, a spacing between the first lens group and the second lens group changes, a spacing between the second lens group and the middle group changes, and a spacing between the middle group and the final lens group changes. The zoom lens satisfies predetermined conditional expressions.

The present invention relates to a reflective eyepiece optical system and a head-mounted near-to-eye display device. The system includes: a first optical element and a second optical element arranged successively in an incident direction of an optical axis of human eyes, and a first lens group located on an optical axis of a miniature image displayer. The first optical element is used for transmitting and reflecting an image light from the miniature image displayer. The second optical element includes an optical reflection surface. The first optical element reflects the image light refracted by the first lens group to the second optical element, and then transmits the image light reflected by the second optical element to the human eyes.

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

Provided is a zoom lens, including, in order from an object side: first positive, second negative, third positive lens units, and rear lens group, in which intervals between the first and second lens units, between the second and third lens units, and between the third lens unit and the rear lens group, are respectively is increased, decreased and changed, in which the zoom lens includes an image stabilization unit A configured to move not in an optical axis direction during image blur correction, and an image stabilization unit B configured to rotate around a point on or near the optical axis during the image stabilization, and in which focal lengths of the image stabilization unit B and the zoom lens, maximum value θt of image blur correction angle, and rotation angle of the image stabilization unit B upon the image blur correction angle θt are appropriately set.

A variable magnification optical system consists of, in order from an object side to an image side, a first lens group, a second lens group, and a subsequent lens group. The variable magnification optical system satisfies a predetermined conditional expression for a partial dispersion ratio related to F line, C line, and a wavelength of 1970.09 nm, a d-line back focus of the variable magnification optical system at a telephoto end, a back focus in any one wavelength from a wavelength of 1300 nm to a wavelength of 2325.42 nm at the telephoto end, and a d-line focal length of the variable magnification optical system at the telephoto end.

A zoom lens includes a first lens group, a second lens group, a third lens group, and a fourth lens group that are sequentially arranged from an object side to an image side along an optical axis. The first lens group and the third lens group are fastened, and the second lens group and the fourth lens group move along the optical axis. A first lens from the object side in the first lens group is a biconvex lens, and at least two lenses from the object side in the first lens group are glass lenses. A maximum clear aperture diameter of the zoom lens has the following relationship of 4 mm≤φ≤12 mm, where p is the maximum clear aperture diameter of the zoom lens.

An optical system includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a first focus lens unit having a negative refractive power, and a second focus lens unit having a positive refractive power. The first lens unit is fixed during focusing. The first focus lens unit and the second focus lens unit move so that a distance between the first focus lens unit and the second focus lens unit changes during focusing. The first lens unit includes a single lens which is disposed closest to an object and has a negative refractive power. A predetermined condition is satisfied.

An optical system includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a first focus lens unit having a negative refractive power, and a second focus lens unit having a positive refractive power. The first lens unit is fixed during focusing. The first focus lens unit and the second focus lens unit move so that a distance between the first focus lens unit and the second focus lens unit changes during focusing. The first lens unit includes a single lens which is disposed closest to an object and has a negative refractive power. A predetermined condition is satisfied.

A variable magnification optical system consists of, in order from an object side to an image side, a first lens group, a second lens group, and a subsequent lens group. The variable magnification optical system satisfies a predetermined conditional expression for a partial dispersion ratio related to F line, C line, and a wavelength of 1970.09 nm, a d-line back focus of the variable magnification optical system at a telephoto end, a back focus in any one wavelength from a wavelength of 1300 nm to a wavelength of 2325.42 nm at the telephoto end, and a d-line focal length of the variable magnification optical system at the telephoto end.

A zoom optical system (ZL) comprises, in order from an object: a first lens group (G1) having a positive refractive power; a second lens group (G2) having a negative refractive power; a third lens group (G3) having a positive refractive power; and a subsequent lens group (GR), wherein upon zooming, a distance between the first lens group (G1) and the second lens group (G2) changes, a distance between the second lens group (G2) and the third lens group (G3) changes, and a distance between the third lens group (G3) and the subsequent lens group (GR) changes, the subsequent lens group (GR) comprises a focusing lens group that moves upon focusing, and following conditional expressions are satisfied, 3.70<f1/(−f2)<5.00, 3.20<f1/f3<5.00, where f1: a focal length of the first lens group (G1), f2: a focal length of the second lens group (G2), and f3: a focal length of the third lens group (G3).