A freeform surface off-axis three-mirror optical system comprises a primary mirror, a secondary mirror, a tertiary mirror, an aperture stop located on the secondary mirror, and an image surface. An incident light beam emitted from an object irradiates and is reflected on the primary mirror to form a first reflected light beam. The first reflected light beam irradiates and is reflected on the secondary mirror to form a second reflected light beam. The second reflected light beam passes through the incident light beam, and then irradiates and is reflected on the tertiary mirror to form a third reflected light beam. The third reflected light beam passes through the incident light beam and does not pass through the secondary mirror, and finally reaches the image surface for imaging. A reflective surface of each of the primary mirror, the secondary mirror, and the tertiary mirror is an xy polynomial freeform surface.

A freeform surface off-axis three-mirror optical system comprises a primary mirror, a secondary mirror, a tertiary mirror, an aperture stop located on the secondary mirror, and an image surface. An incident light beam emitted from an object irradiates and is reflected on the primary mirror to form a first reflected light beam. The first reflected light beam irradiates and is reflected on the secondary mirror to form a second reflected light beam. The second reflected light beam passes through the incident light beam, and then irradiates and is reflected on the tertiary mirror to form a third reflected light beam. The third reflected light beam passes through the incident light beam and does not pass through the secondary mirror, and finally reaches the image surface for imaging. A reflective surface of each of the primary mirror, the secondary mirror, and the tertiary mirror is an xy polynomial freeform surface.

A method for assembling a head mounted display includes providing a rigid structural frame, and forming an inner optical assembly by assembling optical components to the structural frame including at least one micro-display configured to generate an image, and at least one reflective optical component configured to direct the image to a user's eye. The method includes assembling an outer frame to the inner optical assembly to provide protection for the optical components and customization of the head-mounted display for the user.

A telescope system (100) comprises a steering minor (M5) arranged in a part of its optical path (L5-L6) between a first telescope stage (10) and a second telescope stage (20). The steering mirror (M5) is configured to controllably rotate over a rotation angle (θm) for controlling a view angle (θv) of the telescope system (100) from the entrance aperture (A1). The steering mirror (M5) is disposed at an intermediate pupil (Pi) of the telescope system (100), at which position an image of the aperture stop (As) is formed by one or more of the optical components (M7, M6) there between.

In one aspect, an apparatus includes a first aspheric refractive surface defined by a first polynomial and positioned to receive input light, and a first aspheric mirror surface comprising a first reflective coating, the first mirror surface defined by a second polynomial and positioned to receive light from the first aspheric refractive surface. The apparatus includes a second aspheric mirror surface comprising a second reflective coating, the second aspheric mirror surface defined by a third polynomial and positioned to receive light from the first aspheric mirror surface, and a second aspheric refractive surface defined by a fourth polynomial and positioned to receive light from the second aspheric mirror surface, wherein the first aspheric refractive surface, the first aspheric mirror surface, the second aspheric mirror surface, and the second aspheric refractive surface are arranged to have a fixed alignment with respect to each other as part of a monolithic structure.

A projection optical unit for microlithography includes a plurality of mirrors and has a numerical aperture having a value larger than 0.5. The plurality of mirrors includes at least three grazing incidence mirrors, which deflect a chief ray of a central object field point with an angle of incidence of greater than 45°. Different polarized light beams passing the projection optical unit are rotated in their polarization direction by different angles of rotation. The projection optical unit includes first and second groups of mirrors. The second group of mirrors includes the final two mirrors of the plurality of mirrors at the image side. A linear portion in the pupil dependence of the total geometrical polarization rotation of the projection optical unit is less than 20% of a linear portion in the pupil dependence of the geometrical polarization rotation of the second group of mirrors.

A method of designing an freeform surface off-axial three-mirror imaging system is provided. The method includes: establishing an initial system and T (T≥2) object-image relationships according to a design goal, and selecting M feature fields for each object-image relationship; using feature rays of the T object-image relationships to construct a freeform surface system by using the initial system; step (S3), the freeform surface system obtained in step (S2) is used as another initial system, using iterative process to reduce a deviation between actual intersection points and ideal target points of the feature rays and feature surfaces, iteratively reconstructing free-form surfaces in the free-form surface system.

The present application relates to a method for designing a nonsymmetric freeform surface optical system, and the method including the following steps establishing an initial plane system. The initial plane system is consistent with the expected system structure, but there is no focal power in the initial plane system. The image plane tilt angle of the initial plane system is defined as θ. The point-by-point method is used to calculate the coordinates and normal vectors of the data points used to construct the freeform surface. The iterative optical system is obtained by iteration; and the iterative optical system is optimized.

An imaging optical system includes a primary reflecting mirror, a secondary reflecting mirror, a tertiary reflecting mirror, and an aperture stop. The imaging optical system has a field of view, a focal length of the field of view that is defined as FFL, and an effective aperture of a field of view entrance pupil that is defined as FEPD. The FFL and the FEPD at a central field of view are greater than that at the edge field of views, and the FFL and the FEPD change continuously.

A hybrid reflective/refractive HMD includes a structural frame, refractive optical lens elements, and optics housings coupled to the structural frame and positioned in front of a user's first and second eyes. Light-emitting visual sources and reflective optical surfaces are contained in the optics housings. Visual content is transmitted from light-emitting visual sources to the reflective optical surfaces. The visual content is reflected within the reflective optical surfaces at least four times without passing through a refractive optical lens element. The visual content is transmitted to the user's first eye or the user's second eye. Simultaneous with the transmission of the visual content to the user's first eye or the user's second eye, a real-world view of the outside surrounding environment is transmitted to the user's first eye or the user's second eye. The visual content is overlaid onto the real-world view of the outside surrounding environment.