An optical projection unit includes first and second optical element modules. The first optical element module includes a first housing unit and a first optical element received within the first housing unit and having an optically used first region defining a first optical axis. The second optical element module is located adjacent to the first optical element module and includes a second optical element which defines a second optical axis of the optical projection unit. The first housing unit has a central first housing axis and an outer wall extending in a circumferential direction about the first housing axis. The first optical axis is laterally offset and/or inclined with respect to the first housing axis. The first housing axis is substantially collinear with the second optical axis.

A head mounted display (HMD) includes a display and a pancake lens block. The display with a circular polarizer, comprised of an initial linear polarizer and a first quarter-waveplate with polarizer transmission axis 45 from the waveplate fast axis, emits polarized light. The pancake lens includes a partial reflector, a second quarter-waveplate, and a beam splitting polarizer. The pancake lens receives polarized light from the display. Light propagating through the pancake lens undergoes multiple reflections and transmissions achieved by coordinating changes in polarization of light through these optical elements. To mitigate parasitic light from degrading image quality of the HMD, the fast axis orientation of the first quarter-waveplate is oriented 90 relative to the fast axis orientation of the second quarter-waveplate, and thus the transmission axis of the first polarizer is oriented 90 relative to the transmission axis of the beam splitting polarizer.

Optical systems are provided. In an embodiment, the optical system includes a first anamorphic optic having a first focal length and a first focal line, where the first focal line is parallel to a cross track direction. A second anamorphic optic has a second focal length and a second focal line, where the second focal length is different than the first first focal length. The second anamorphic optic is positioned such that the first focal line and the second focal line are in about the same location. The first and second anamorphic optics are aligned along an optical signal path, and are configured to provide afocal magnification to a signal beam along an along track direction to produce a magnified beam. A line scan imager includes an objective lens and a linear detector, and the second anamorphic optic is configured to direct the magnified beam at the objective lens.

A head up display arrangement for a motor vehicle includes a picture generation unit generating an illuminated image. A first free form mirror is positioned to provide a first reflection of the illuminated image. A second free form mirror is positioned to receive the first reflection of the illuminated image and provide a second reflection of the illuminated image. A windshield of the motor vehicle is positioned to receive the second reflection of the illuminated image and provide a third reflection that is visible to a driver of the vehicle as a virtual image.

An optical projection unit includes first and second optical element modules. The first optical element module includes a first housing unit and a first optical element received within the first housing unit and having an optically used first region defining a first optical axis. The second optical element module is located adjacent to the first optical element module and includes a second optical element which defines a second optical axis of the optical projection unit. The first housing unit has a central first housing axis and an outer wall extending in a circumferential direction about the first housing axis. The first optical axis is laterally offset and/or inclined with respect to the first housing axis. The first housing axis is substantially collinear with the second optical axis.

A projection objective configured to image an object field in an object plane into an image field in an image field plane includes a reflective unit, a first refractive unit, and a second refractive unit. An optical axis of the first refractive unit is parallel to but displaced from an optical axis of the second refractive unit. The reflective unit includes a first curved mirror and a second curved mirror. The second curved mirror is immediately downstream from the first curved mirror in a path of light from the object plane to the image plane. The projection objective is a microlithography projection objective.

An optical element of an embodiment includes an optical element made of a material transparent to light, the optical element including: a back surface facing the front surface; and a connection surface. The front surface includes a recessed surface in a region facing the connection surface. The recessed surface has a point closest to the connection surface as a closest point, and has a first singular point other than the closest point.

An obstacle detecting unit includes a reflective mirror formed to reflect light which is incident from a front area and a lower portion of the front area below a central portion of the reflective mirror; a catadioptric lens disposed coaxially with the reflective mirror in an upper portion of the reflective mirror, the catadioptric lens on which light incident from the front area and an upper portion of the front area; and an image forming module disposed coaxially with the reflective mirror below the reflective mirror, the image forming module on which the light reflected by the reflective mirror is incident, wherein a through hole is formed in the central portion of the reflective mirror, and the light coming out of the catadioptric lens passes through the through hole and then is incident on the image forming module.

A head mounted display (HMD) includes a field curvature corrected (FC) display to mitigate field curvature in an image that is output to a user's eyes. The FC display includes elements that generate the image light and elements to mitigate field curvature from the image light. The FC display may include a display panel with lenses, a display panel with a reflective polarizer and reflective surface, or other optical elements. The FC display may include a pancake lens configuration including a polarized display with a quarter wave plate, a reflective mirror, and a polarization reflective mirror.

An optical projection unit includes first and second optical element modules. The first optical element module includes a first housing unit and a first optical element received within the first housing unit and having an optically used first region defining a first optical axis. The second optical element module is located adjacent to the first optical element module and includes a second optical element which defines a second optical axis of the optical projection unit. The first housing unit has a central first housing axis and an outer wall extending in a circumferential direction about the first housing axis. The first optical axis is laterally offset and/or inclined with respect to the first housing axis. The first housing axis is substantially collinear with the second optical axis.