Certain aspects of a novel weapon sight system combine a direct view, a visible light video view, and an infrared (IR) video view mode. Each of the view modes may be viewed individually or simultaneously with one or more of the other view modes through a single viewing aperture. Further, the one or more view-modes may be provided while providing a bore-sighted reticle superimposed on the selected view. Further, the reticle may be powered separately from the video view electronics enabling use of the reticle regardless of the power status video view electronics.

An optical alignment method includes providing an emitted radiation beam which includes a first peak wavelength and a second peak wavelength to a chromatic aberration enhancement component which increases a chromatic aberration of the emitted radiation beam, providing a first incident radiation beam having the first peak wavelength and a second incident radiation beam having the second peak wavelength which is shorter than the first peak wavelength to respective first and second alignment marks located at different vertical levels in a device under test, detecting reflected radiation from the first and second alignment marks, and using the detected reflected radiation for optical alignment of layers in the device under test.

An optical alignment method includes providing an emitted radiation beam which includes a first peak wavelength and a second peak wavelength to a chromatic aberration enhancement component which increases a chromatic aberration of the emitted radiation beam, providing a first incident radiation beam having the first peak wavelength and a second incident radiation beam having the second peak wavelength which is shorter than the first peak wavelength to respective first and second alignment marks located at different vertical levels in a device under test, detecting reflected radiation from the first and second alignment marks, and using the detected reflected radiation for optical alignment of layers in the device under test.

A sighting arrangement, comprising an illuminated mark and a prism system consisting of a first prism and a second prism which are connected to each other via a dichroic reflector surface, the prism system comprising a sight axis and a superimposition axis for imaging the illuminated mark onto a sighted target. The bottom surface, via which the imaging beam path emanating from the illuminated mark is coupled into the prism system, and the convexly curved mirror surface, which is absolutely necessary for collimating the imaging beam path, are located on the same side of the prism system, namely on the mounting side facing a device on which the prism system is mounted as intended. As a result, the prism system has a flat top surface which does not limit the field of view section determined by the visible edges of the prism system.

Certain aspects of a novel weapon sight system combine a direct view, a visible light video view, and an infrared (IR) video view mode. Each of the view modes may be viewed individually or simultaneously with one or more of the other view modes through a single viewing aperture. Further, the one or more view-modes may be provided while providing a bore-sighted reticle superimposed on the selected view. Further, the reticle may be powered separately from the video view electronics enabling use of the reticle regardless of the power status video view electronics.

An optical system is provided, including a Galilean magnification device, including an objective lens and an eyepiece lens arranged along an axis. One of the objective lens and the eyepiece lens is a positive lens and the other is a negative lens, thereby defining an image working distance; a reticle device within the Galilean magnification device, including a holographic element, the reticle device being configured to receive light for illuminating the holographic element from off the axis and to direct light from the holographic element on the axis, so that light from the holographic element is set at the image working distance by the eyepiece lens. There is also described a method for recording a holographic reticle for use in a Galilean magnification device.

A disclosed medical observation system includes a capturing unit operable to capture an image of an observation target; and a light projection unit operable to project light on the observation target, outside a capturing area that is captured by the capturing unit and in a periphery of the capturing area, the light enabling recognition of a capturing state of the capturing unit.

A display medium comprising: a multilayered substrate including a polarized light separation layer and a phase difference layer; and a first reflective layer provided on a surface of the multilayered substrate on a side with the polarized light separation layer, wherein: the polarized light separation layer can reflect circularly polarized light which has one rotation direction D.sub.A, and can transmit circularly polarized light which has an opposite rotation direction to the rotation direction D.sub.A; the first reflective layer can reflect circularly polarized light which has one rotation direction D.sub.B1, and can transmit circularly polarized light which has an opposite rotation direction to the rotation direction D.sub.B1; and the rotation direction D.sub.A of the circularly polarized light that the polarized light separation layer can reflect and the rotation direction D.sub.B1 of the circularly polarized light that the first reflective layer can reflect are the same as each other.

A holographic optical system is provided, including: a light source; a collimator, arranged to receive from the light source and having an output surface configured to provide collimated light, optical properties of the collimator generating aberrations in the collimated light; and an aberration-compensating holographic optical element having a planar diffractive surface arranged to receive collimated light from the output surface, the planar diffractive surface having optical properties such that output light from the planar diffractive surface is compensated for the aberrations generated by the collimator.

A high-assurance headtracking system for a head worn display (HWD) incorporating ground-truth fiducials is disclosed. In embodiments, the headtracking system includes a camera fixed to a mobile platform (e.g., an aircraft cockpit) and oriented toward a pilot wearing the HWD. Images captured by the camera detect fiducial markers attached to the HWD (and fixed in a device reference frame) and static fiducial markers fixed to the mobile platform, each static fiducial marker including a constellation of individual markers having a known position and orientation in the platform reference frame. The headtracking system include control processors for analyzing the images and identifying therein the device-frame and static fiducial markers. The headtracking system determines a device pose of the HWD relative to the platform reference frame and monitors the device pose for drift or error based on the known positions of the identified static fiducial markers.