Provided are methods for geometric intrinsic camera calibration using a diffractive optical element. Some methods described include receiving, by at least one processor, at least one image captured by a camera based on a plurality of light beams received from a diffractive optical element aligned with an optical axis of the camera, the plurality of light beams having a plurality of propagation directions associated with a plurality of view angles. The at least one processor identifies a plurality of shapes in the image, determines a correspondence between the plurality of shapes in the image and the plurality of light beams, and identifies one or more intrinsic parameters of the camera that minimize a reprojection error function based on the plurality of shapes in the image and the plurality of propagation directions. Systems and computer program products are also provided.

Examples are provided related to using multiplexed diffractive elements to improve eye tracking systems. One example provides a head-mounted display device comprising a see-through display system comprising a transparent combiner having an array of diffractive elements, and an eye tracking system comprising one or more light sources configured to direct light toward an eyebox of the see-through display system, and also comprising an eye tracking camera. The array of diffractive elements comprises a plurality of multiplexed diffractive elements configured to direct images of a respective plurality of different perspectives of the eyebox toward the eye tracking camera.

An array that focuses UVC light energy from a UVC light source into a beam and thereby reduces the degradation of UVC light energy at a set distance. Singular or plural optics, or lens assemblies forming the array can each use a Diffractive Optical Element (“DOE”) with a beam width of UVC energy with acceptable transmission through the DOE, which transmits a UVC beam through a relay lens which thereby allows an extended distance greater that the fall off rate of the standard UVC energy source. Lens assemblies can include a series of spacers and lenses that allow the manipulation of a wide angle UVC light source for the purpose of focusing the light to a desired beam shape, i.e., a thin line or bar, or a pin point. Each of the optics may have one or more spacers set at a specific width to add to the total beam shaping of the lenses.

An optical waveguide device for use in a head up display. The waveguide device provides pupil expansion in two dimensions. The waveguide device comprises a primary waveguide and a secondary waveguide, the secondary waveguide being positioned on a face of the primary waveguide. The secondary waveguide has a diffraction grating on a face opposite to the face which contacts the primary waveguide. The diffraction grating diffracts light into more than one diffraction order. Rays diffracted into a non-zero order are trapped in the secondary waveguide by total internal reflection.

A diffractive optical element includes: a substrate; a protrusion and recess portion that is formed on one surface of the substrate and imposes predetermined diffraction on incident light; and an antireflection layer provided between the substrate and the protrusion and recess portion. An effective refractive index difference Δn in a wavelength range of the incident light between a first medium constituting a protrusion of the protrusion and recess portion and a second medium constituting a recess of the protrusion and recess portion is 0.70 or more. An exit angle range θ.sub.out of diffraction light exiting from the protrusion and recess portion when the incident light enters the substrate from a normal direction of the substrate is 60° or more. Total efficiency of diffraction light exiting from the protrusion and recess portion in the exit angle range is 65% or more.

An optical device includes a first waveguide having a first side and an opposing second side, a spatial light modulator configured to project image light, one or more lenses disposed between the spatial light modulator and the first waveguide, and a first in-coupler coupler coupled with the first waveguide. The spatial light modulator is positioned on the first side of the first waveguide. The first in-coupler is positioned to receive the image light projected by the spatial light modulator and transmitted through the one or more lenses and to redirect at least a first portion of the image light so that the first portion of the image light enters the first waveguide and undergoes total internal reflection inside the first waveguide.

Diffraction-based imaging systems are described. Aspects of the technology relate to imaging systems having one or more sensors inclined at angles with respect to a sample plane. In some cases, multiple sensors may be used that are, or are not, inclined at angles. The imaging systems may have no optical lenses and are capable of reconstructing microscopic images of large sample areas from diffraction patterns recorded by the one or more sensors. Some embodiments may reduce mechanical complexity of a diffraction-based imaging system. A diffractive imaging system comprises a light source, a sample support configured to hold a sample along a first plane, and a first sensor comprising a plurality of pixels disposed in a second plane that is tilted at an inclined angle relative to the first plane. The first sensor is arranged to record diffraction images of the light source from the sample.

An atmosphere starry sky light for festival entertainment is provided. The constellation unit is configured to switch patterns of twelve constellations and perform projection display on the patterns of the twelve constellations. The starry sky unit is configured to project a starry sky background. The background unit is configured to project patterns of aurora, clouds, and ripples. The planetary unit is configured to switch patterns of a planet, and to project and display a planetary image. The constellation unit, the planetary unit, the starry sky unit and the background unit form a panoramic image of the cosmic starry sky by superimposing and combining.

The present disclosure relates to an image sensor comprising a first layer of photoelectric material and a diffraction grating located between said first layer and the face of the sensor configured to receive light rays.

A switchable optical assembly comprises a switchable waveplate configured to be electrically activated and deactivated to selectively alter the polarization state of light incident thereon. The switchable waveplate comprises first and second surfaces and a liquid crystal layer disposed between the first and second surfaces. The first liquid crystal layer comprises a plurality of liquid crystal molecules. Said first and second surfaces may be curved. Said plurality of liquid crystal molecules may vary in tilt with respect to said first and second surfaces with outward radial distance from an axis through said first and second surfaces and said liquid crystal layer in a plurality of radial directions. The switchable waveplate additionally comprises a first plurality of electrodes to apply an electrical signal across said first liquid crystal layer.