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.

This optical system (OL) comprises a front group (GA), an aperture stop (S), and a rear group (GB) that are arranged in order from the object side along an optical axis. The rear group (GB) has a focusing lens group (GF1) disposed closest to the object side in the rear group (GB) and having negative refractive power, during focusing, the focusing lens group moves along the optical axis, and the spacing between adjacent lens groups changes, and the following conditional expression is satisfied. 0.50<ST/TL<0.95, where ST is the distance on the optical axis from the aperture stop (S) to an image surface (I), and TL is the total length of the optical system (OL).

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 is provided. The optical system includes a first assembly and a second assembly. The first assembly includes a first welding portion. The second assembly is affixed on the first assembly and includes a second welding portion. The first welding portion is affixed on the second welding portion by welding.

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.

The invention relates to an optical zoom device (1) Optical zoom device (1), comprising a first lens assembly (2), and a second lens assembly (3) following the first lens assembly (2) in the direction of an optical axis (A) of the optical zoom device (1) so that light (L) can pass through the first lens assembly (2) and thereafter through the second lens assembly when travelling along the optical axis (A), wherein said lens assemblies each comprise a focus-adjustable lens (31, 32) as well as an electropermanent magnet (107, 207) or a shape memory alloy (120, 220) for actuating the respective lens (31, 32).

A camera for a portable electronic device is provided. The camera comprises a housing, a first lens assembly (101) having a first optical axis, a second lens assembly (105, 107) having a second optical axis, a mirror (103) placed at a point of intersection of the first and the second optical axis, and an image sensor (109) placed on the second optical axis. Furthermore, the camera comprises an image stabilisation apparatus, comprising a first detector configured to generate a first signal in response to a rotation of the camera about an axis that is perpendicular to both the first and the second optical axis and a first actuator configured to rotate the first lens assembly (101) and the mirror (103) in response to the first signal relative to the housing about a first rotation axis perpendicular to the first and second optical axis for compensating the rotation of the camera.

Cameras with OIS capable of performing multi zoom super macro photography and handheld electronic devices comprising such cameras. A camera may include a lens comprising N lens elements L.sub.1-L.sub.N divided into two or more lens groups arranged along a lens optical axis starting with L.sub.1 on an object side and ending with L.sub.N on an image side, adjacent lens groups separated by a respective air-gap d.sub.1 along the lens optical axis; an image sensor with a sensor diagonal SD between 7 and 20 mm separated from lens element L.sub.N by an air-gap d.sub.2 along the lens optical axis; and an actuator for controlling air-gaps d.sub.1 and d.sub.2 to switch the camera between M≥1 operative pop-out states and a collapsed state and to focus the camera on an object at an object-lens distance of less than 30 cm.

Provided is a zoom lens, including, in order from an object side, a positive first lens unit, a negative second lens unit, a positive third lens unit, a negative fourth lens unit, and a positive fifth lens unit, in which an interval between each pair of adjacent lens units is changed during zooming, in which the second lens unit moves during focusing, and includes, in order from the object side to the image side, a negative lens, a negative lens, a positive lens, and a negative lens, and in which a focal length of the second lens unit, a thickness of the second lens unit on an optical axis, a refractive index of a material of the positive lens included in the second lens unit, and an average value of refractive indices of materials of the negative lenses included in the second lens unit are each appropriately set.

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.