Methods, devices and systems for improved fabrication and measurement of holographic elements are described. One example method includes directing a reference and an object beam toward a holographic material for formation of a diffraction grating in the holographic material, and blocking one of the reference or the object beams to prevent the beam from reaching the holographic material for at least a portion of time during which the diffraction grating is being formed. During the blockage of the beam, a power level of a diffracted beam associated with the reference or the object beam that is not being blocked is measured. Based on the measured power level, it is then determined whether a particular diffraction grating efficiency is reached. The described techniques enable real-time measurement of diffraction grating efficiency as the grating is being formed and enable improved fabrication of holographic elements hat must meet precise diffraction grating efficiency requirements.

A holographic display device includes a display panel for emitting a first image light and a diffraction component on an optical path of the first image light. The first image light includes first and second colors of light. The diffraction component diffracts the first color light at a first diffraction efficiency and diffracts the second color light at a second diffraction efficiency. The first color light and the second color light after diffraction are mixed together in a second image light for generating holographic images. By emitting the first color light and the second color light in the first image light at the same grayscale value, a ratio of intensities of the first color light and the second color light becomes inversely proportional to a ratio of the first diffraction efficiency and the second diffraction efficiency.

Provided is a hologram printing method and apparatus using a hologram medium light efficiency map. A hologram printing method according to an embodiment emits a laser to a hologram medium, acquires an image by photographing light diffracted from the hologram medium, generates a light efficiency map of the hologram medium from the acquired image, and records hogels on the hologram medium by referring to the generated light efficiency maps of the hologram medium. Accordingly, light efficiency is measured on each hogel area, and hologram printing is performed by adjusting an intensity of a laser of each wavelength according to a hogel, so that uniformity of luminance and color of a hologram printing result can be enhanced.

A method for producing a holographic optical element. The method includes a step of exposing a recording material to a phase pattern which is provided by a first modulated light beam with a first phase portion. Furthermore, the method includes a step of an additional exposure of the recording material to the phase pattern, which is provided by a second modulated light beam with a second phase portion, wherein the second phase portion has a phase offset with respect to the first phase portion in order to produce a holographic optical element.

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.

A method of manufacturing a full-color holographic optical element in a full-color holographic optical element manufacturing apparatus including a lens and a holographic recording medium located farther away than a focal length of the lens, the method including: allowing a signal beam including a mixture of laser beams having wavelengths of R (Red), G (Green), and B (Blue) to be incident on the lens; and recording a hologram in such a manner that a reference beam including a mixture of laser beams having wavelengths of R, G, and B is allowed to be incident on the holographic recording medium, wherein the holographic recording medium is configured with a single medium.

A system includes a laser emitting a laser beam, a beam expander expanding the laser beam, a beam splitter prism splitting the expanded laser beam into first and second split light beams, a liquid crystal box containing polymer-dispersed liquid crystal, first and second reflectors reflecting the first and second split light beams to the liquid crystal box, respectively, and an attenuator arranged on an optical path between the beam expander and the liquid crystal box. The attenuator gradually attenuates at least one of the laser beam, the expanded laser beam, the first split light beam, or the second split light beam along a first set curve. The first split light beam and the second split light beam form interference fringes at the liquid crystal box to expose the polymer-dispersed liquid crystal to form a polymer-dispersed liquid crystal holographic grating having a diffraction efficiency decreasing along a second set curve.

The present invention provides a light-guiding plate which is applicable to incident rays over a wide ray angular range and wide wavelength rage, and is able to suppress a decrease in optical efficiency. A light-guiding plate 200 having a light diffracting portion 1200 for diffracting incident light by a multiple-recorded hologram is configured such that, in the light diffracting portion, when light 1210 of a single wavelength having a certain angular range is incident, at least two or more outgoing rays 1220 are discretely emitted with a first angular space θs, and the emitted rays each have a second angular range θa, and the first angular space θs is equal to or larger than the second angular range θa.

An electronic device may include an optical system that redirects light from a display module towards an eye box along an optical path. The optical path may include a holographic coupler and a resolution-enhancing holographic element. The holographic element may include a first set of holograms and the coupler may include a second set of holograms. The first set of holograms may be characterized by a first set of selectivity curves having first primary lobes. The second set of holograms may be characterized by a second set of selectivity curves having second primary lobes that overlap the first primary lobes. This may configure the holographic element to narrow the second selectivity curves by diffracting some of the light out of the optical path, thereby optimizing the resolution of images in the light provided to the eye box.

A holographic display device includes a display panel for emitting a first image light and a diffraction component on an optical path of the first image light. The first image light includes first and second colors of light. The diffraction component diffracts the first color light at a first diffraction efficiency and diffracts the second color light at a second diffraction efficiency. The first color light and the second color light after diffraction are mixed together in a second image light for generating holographic images. By emitting the first color light and the second color light in the first image light at the same grayscale value, a ratio of intensities of the first color light and the second color light becomes inversely proportional to a ratio of the first diffraction efficiency and the second diffraction efficiency.