An imaging optical unit for projection lithography has a plurality of mirrors for guiding imaging light from an object field into an image field. The object field is spanned by a first, larger object field dimension and along a second, smaller object field dimension. The imaging optical unit has at least two GI mirrors and at least one NI mirror. The NI mirror is arranged between two GI mirrors in the imaging light beam path. A used reflection surface of the NI mirror has an aspect ratio between a surface dimension along a first reflection surface coordinate and a surface dimension along a second reflection coordinate parallel to the second object field dimension. The aspect ratio being less than 4.5. An imaging optical unit with reduced production costs emerges.

A method for designing off-axial optical system with freeform surfaces is provided. An initial system is established. A freeform surface of the off-axial optical system that needs to be solved is defined as a freeform surface. A number of feature rays are selected. A number of intersections of the feature rays with the freeform surface are calculated point by point based on a given object-image relationship and a vector form of Snell's law. A number of first feature data points are obtained from the intersections and surface fitted to obtain the freeform surface. All the freeform surfaces of the off-axial optical system that need to be solved are obtained by the method above to form a before-iteration off-axial optical system. The before-iteration off-axial optical system is used as the initial system for multiple iterations to obtain an after-iteration off-axial optical system.

A method for designing freeform surface off-axial three-mirror imaging system with a real exit pupil is related. An initial system is established. A surface located before the real exit pupil is defined as surface M. A number of feature rays are selected. A number of ideal intersections of the feature rays with surface M are calculated. A number of intersections of the feature rays with each surface before surface M are calculated, and each surface before surface M is obtained by surface fitting. A number of intersections of the feature rays with surface M are calculated, and surface M is obtained by surface fitting. Surface M substitute for an initial surface, and repeating steps above, until the intersections of the feature rays with surface M are close to the ideal intersections, and the intersections of the feature rays with an image surface are close to the ideal image points.

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.

A head-up display device reflects a display light on a projection member to display a virtual image. A light condensing unit causes condensation and collimates an illumination light from a light source unit. A liquid crystal element includes forms an image illuminated with the illumination light. The liquid crystal element emits the display light of the image in a light flux form in an emission direction corresponding to an incident direction of the illumination light. A positive optical element has a positive refractive power. A negative optical element has a negative refractive power. Both of the optical elements are located on the optical path and guide the display light from the liquid crystal element toward the projection member to enlarge a virtual image. The negative optical element on the optical path is located closer to the liquid crystal element than the positive optical element.

A method for designing a oblique camera lens comprising: step (S1), establishing an initial system, the initial system comprises a primary mirror initial structure, a secondary mirror initial structure, and a tertiary mirror initial structure; step (S2), building a new image relationship; step (S3), keeping the primary mirror initial structure and the secondary mirror initial structure unchanged; selecting a plurality of first feature rays; step (S4), keeping the secondary mirror initial structure and the tertiary mirror unchanged; selecting a plurality of fields and a plurality of second feature rays.

A cloaking device includes an object-side, an image-side, an object-side curved cloaking region (CR) boundary having an outward facing mirror surface and an inward facing surface, and an image-side curved CR boundary an outward facing mirror surface and an inward facing surface. A cloaked region is bounded by the inward facing surfaces of the object-side curved CR boundary and the image-side curved CR boundary. At least one exterior boundary with an inward facing mirror surface is spaced apart from the object-side curved CR boundary and the image-side curved CR boundary. Light from an object positioned on the object-side of the cloaking device and obscured by the cloaked region is redirected around the cloaked region to form an image of the object on the image-side of the cloaking device such that the light from the object appears to pass through the CR.

A non-relayed reflective triplet and a double-pass imaging spectrometer including the reflective triplet configured as its objective. In one example the reflective triplet includes a primary mirror that receives and reflects electromagnetic radiation from a viewed scene and defines an optical axis of the optical system, a secondary mirror that receives and reflects the electromagnetic radiation reflected from the primary mirror, and a tertiary mirror that receives the electromagnetic radiation reflected from the secondary mirror and focuses the electromagnetic radiation onto an image plane to form an image of the viewed scene. The primary, secondary, and tertiary mirrors together are configured to form a virtual exit pupil for the optical system, the image plane being located between the tertiary mirror and the virtual exit pupil. The reflective triplet is on-axis in aperture and off-axis in field of view.

A head mounted display device includes a structural frame arranged generally along a X-axis and a Y-axis for viewing along a Z-axis, the X, Y, and Z axes being mutually perpendicular. A micro-display is coupled to the structural frame, and configured to project visual content in a substantially forward direction along the Z-axis away from a user. A group of one or more optical elements with reflective optical surfaces is coupled to the structural frame and respectively positioned on a front side of the micro-display to reflectively guide a light ray bundle in a non-pupil forming optical path from the micro-display to a user's eye to provide an image to the user's eye such that the light rays of the light ray bundle entering the user's eye are essentially parallel to make the image visible to the user with varied positions of the user's pupil.

An imaging optical unit for projection lithography has a plurality of mirrors for guiding imaging light from an object field into an image field. The object field is spanned by a first, larger object field dimension and along a second, smaller object field dimension. The imaging optical unit has at least two GI mirrors and at least one NI mirror. The NI mirror is arranged between two GI mirrors in the imaging light beam path. A used reflection surface of the NI mirror has an aspect ratio between a surface dimension along a first reflection surface coordinate and a surface dimension along a second reflection coordinate parallel to the second object field dimension. The aspect ratio being less than 4.5. An imaging optical unit with reduced production costs emerges.