A diffractive optical element exerts a diffractive action on a display light that is emitted from a display unit. A folding mirror is provided on the opposite side of the diffractive optical element from the display unit to reflect the display light. The diffractive optical element includes a transmissive action part and a diffractive and reflective action part. The transmissive action part exerts a transmissive action to transmit therethrough the display light, which is incident from the display unit and is in a first polarization state, toward the folding mirror. The diffractive and reflective action part exerts a diffractive and reflective action to diffract and reflect the display light, which is reflected by the folding mirror and is in a second polarization state opposite to the first polarization state, toward the projection portion on an optical path.

An optical device includes a stack of multiple grating structures, each of which includes a plurality of sublayers of liquid crystal material. Each sublayer of liquid crystal material includes laterally extending repeating units, each formed of a plurality of liquid crystal molecules. The repeating units of the liquid crystal layers are lateral offset from one another, and defined a tilt angle. The grating structures forming the stack of grating structure have tilt angles of different magnitudes. The grating structures may be configured to redirect light of visible or infrared wavelengths. Advantageously, the different tilt angles of the stack of grating structures allows for highly efficient diffraction of light incident on the grating structures at a wide range of incident angles.

In the prior art, a scanning element used for Lidar in the self-driving car technology employed a mirror or the like continuously rotated by MEMS, and due to the inertia of the mirror or the like, the scanning element was suited for a raster scan that scans a scene in one stroke, but was incapable of discontinuous movement from one arbitrary point to another, and programmable scanning with an arbitrary frequency in an arbitrary pattern, as fast as the raster scan. In the present invention, there was fabricated Lidar, which is composed of a polarization diversity scheme and a scanning element, wherein the polarization diversity scheme uses two polarization gratings, each polarization grating having a thickness such that it becomes a half-wave plate, wherein birefringent directors of each polarization grating rotate with a period Λ, wherein these polarization gratings are disposed with a desired interval from each other, wherein a half-wave plate is inserted in either one of two paths of separated, exiting right-handed or left-handed circularly polarized light beam, depending on a rotation direction of the circularly polarized light, to thereby enable conversion of light beams into parallel proximate circularly polarized light beams with the same rotational direction, and wherein the scanning element has a multistage structure of polarization switch-polarization grating sets connected in combination, with a polarization switch and a polarization grating being defined as one set.

Provided are: a light guide element in which deterioration in image sharpness can be prevented and the entire area of a display image can be suitably observed irrespective of the visual line of a user, the position of eyes of the user, and the like; and an image display apparatus including the light guide element. The light guide element includes: a light guide plate that includes a first light guide layer and a second light guide layer; and an incidence diffraction element and an emission diffraction element that are laminated on the second light guide layer, in which in a case where a refractive index of the first light guide layer is represented by n1 and a refractive index of the second light guide layer is represented by n2 in the light guide plate, n1<n2 is satisfied.

A device includes a light guide. The device also includes an in-coupling element coupled with the light guide and configured to couple a first image light into the light guide as a second image light propagating inside the light guide via total internal reflection (“TIR”), and to couple a portion of the second image light out of the light guide as a third image light. The device further includes a recycling element coupled with the light guide and configured to couple the third image light back into the light guide as a fourth image light propagating inside the light guide via TIR.

An optical device includes a display configured to generate an image light; and a waveguide optically coupled with the display and configured to guide the image light to an exit pupil of the optical device. The waveguide includes an in-coupling element configured to couple the image light into the waveguide, and an out-coupling element configured to decouple the image light out of the waveguide. The out-coupling element includes a grating having a diffraction efficiency gradient along a predetermined direction at a plane of the grating.

An augmented reality (AR) display apparatus includes an outputter that outputs first radiation including visual information in a predetermined spectrum, a polarizing plate that absorbs a first s-polarized radiation from the first radiation and transmits a first p-polarized radiation and an optical layer that reflects at least a portion of the first p-polarized radiation incident on a first side of the optical layer with a wavelength corresponding to the predetermined spectrum.

A polarization volume grating (PVG) includes a bulk, birefringent medium characterized by a plurality of helical structures with helix axes and a periodicity Λ.sub.y and an anisotropic alignment material having a rotatable optical axis, disposed on a top or bottom surface of the medium. The PVG is characterized in that the optical axis of the alignment material has a continuously rotated optical axis orientation in a plane of the material surface and a periodicity Λ.sub.x, wherein the helix axes are normal to the optical axes in the alignment material surface, further wherein the birefringent medium is characterized by a plurality of controllably slanted refractive index planes having a slant angle φ=±arctan (Λ.sub.y/Λ.sub.x) and a Bragg period Λ.sub.B. Fabrication methods are disclosed.

The Disclosure concerns a laser projection arrangement and a process for the generation of virtual images, the purpose of which is to present a solution which allows a representation of multiple virtual images in different distances or planes and different points of view and that can be manufactured economically. On the arrangement side, this purpose is solved when one of at least two picture generating units that generate virtual images that differ in their wavelength and/or their polarization is arranged and when a holographic optical element is arranged on or in the projection surface. On the process side, the purpose is solved when two virtual images with different wavelengths and/or different polarizations are generated, when a holographic optical element is provided which exhibits different optical properties for different wavelengths and/or different polarizations, and when, in the case of projection of the virtual images while making use of the holographic optical element, the virtual images are represented, due to the different optical properties, at different distances from the driver and/or in different points of view from the driver.

An extended field of view (FOV) is provided by an exit pupil expander in a near-eye display system that uses a waveguide with multiple diffractive optical elements (DOEs) for in-coupling light, expanding the pupil in two directions, and out-coupling light to a system user's eye. Left and right in-coupling DOEs in-couple pupils respectively produced by a pair of imagers—one imager provides a left portion of the FOV and the other imager provides the right portion. The left portion and right portion of the FOV respectively propagate in a left and right intermediate DOEs which expand the pupil in a first direction and diffract light to an out-coupling DOE. The out-coupling DOE expands the pupil in a second direction, stitches the extended FOV together by combining the left and right portions of the FOV produced by the imagers, and out-couples the extended FOV to the user's eye.