Apparatus comprising a projection device for projecting an image, a transparent projection screen for displaying the projected image and a secondary image surface on an opposite side of the screen to the projector device and where an undesired secondary image appears. Different arrangements for the management of the undesired secondary image are disclosed.

A holographic projection system includes a SLM that receives a light beam and generates a modulated beam projected at an eyebox, where: the modulated beam includes multiple versions of a test image; and the test image includes bright objects and transparent regions, which are selected dark areas of interest for measuring luminance. A control module runs a test to characterize contrast in each of multiple virtual image planes including: controlling the SLM to generate the modulated beam; measuring luminance levels of each of the versions of the test image displayed in the virtual image planes; calculating contrast ratios based on the luminance levels of each of the versions of the test image; determining whether the contrast ratios are within predetermined ranges of predetermined contrast ratios; and adjusting operation of the SLM in response to one of the contrast ratios not being within a corresponding one of the predetermined ranges.

A method for generating a holographic image, a signal processor, a holographic image display device, a wearable apparatus, and an onboard head-up display apparatus. The method comprises: performing holographic transformation on the basis of a target amplitude phase distribution of a target image to obtain a holographic phase image; performing phase quantization of the holographic phase image to obtain a quantized holographic image; performing inverse holographic transformation of the quantized holographic image to obtain a reconstructed image; if the reconstructed image satisfies a preset condition, determining that the quantized holographic image is a target holographic image; if not, constraining the amplitude phase of the reconstructed image and, on the basis of the amplitude phase constrained image, continuing iteration. The present method can rapidly and effectively implement monochrome or multi-colour high contrast ratio, low noise real-time holographic image generation and display, and the imaging distance can be freely adjusted.

Disclosed are an active complex spatial light modulation method and apparatus for an ultra-low noise holographic display. The active complex spatial light modulation apparatus includes a substrate and a petal antenna including three petal patterns arranged on the substrate, dividing a complex plane into three phase sections, and modulating the input light into three-phase amplitude values corresponding to the phase sections. The petal antenna may have a point symmetry shape based on the center point of the petal antenna.

In an approach to security for displayed confidential holographic objects, one or more computer processors receive a request from a user to display a holographic object in association with a device. One or more computer processors identify content to be moved to the holographic object. One or more computer processors determine the content includes confidential information. One or more computer processors request authentication from the user. One or more computer processors receive the authentication from the user. One or more computer processors create a holographic boundary, where the holographic boundary blocks a view of the holographic object from one or more unauthorized users. One or more computer processors display the holographic boundary. One or more computer processors display the holographic object in association with the device.

An aircraft cabin assembly is depicted and described having a cabin wall, which surrounds a cabin interior space and has a wall surface facing the cabin interior space, and having a light source, which is provided in order to emit light onto the wall surface. The problem of providing an aircraft cabin assembly which, irrespective of the light outside of the aircraft cabin assembly, as effectively as possible gives a passenger in the cabin interior space the impression that the cabin interior space is larger than it actually is, is solved in that the wall surface has a holographic image of an object and in that the light source is designed to emit the kind of light onto the wall surface that allows the holographic image to be seen as a three-dimensional image of the object which is the subject of the holographic image.

The display apparatus of the present disclosure includes an imaging light generating device and an optical system on which imaging light emitted from the imaging light generating device is incident. The optical system includes a first optical unit having positive power, a second optical unit having a positive power and including a first diffraction element, a third optical unit having positive power, and a fourth optical unit having positive power and including a second diffraction element forming an exit pupil, the first optical unit, the second optical unit, the third optical unit, and the fourth optical unit being aligned in order along an optical path of the imaging light. The second diffraction element is constituted of a volume hologram and has, in a cross-sectional view of the volume hologram, interference fringes continuously varying in pitch and inclination thereof from one end toward another end of the second diffraction element.

A hologram that includes a formation layer and a reflection layer that are laminated. The formation layer has an optical phase modulation structure on a first interface in contact with the reflection layer. When reference light emitted from a point light source enters through a second interface different from the first interface of the formation layer, the entirety or part of an image to be reconstructed by the optical phase modulation structure is reconstructed as spatial information on the point light source side relative to the second interface.

A lighting device, in particular a rear luminaire, for a vehicle is provided. The lighting device has a hologram and a light source for illuminating the hologram. An image, more particularly a real image, is thereby generated, which can also lie outside the physical boundaries of the lighting device.

A display device includes a light source, a waveguide element, a liquid crystal coupler, a first holographic optical element and a second holographic optical element. The light source is configured to emit light. The waveguide element is located above the light source. The liquid crystal coupler is located between the waveguide element and the light source. The first holographic optical element is located on a top surface of the waveguide element, in which the liquid crystal coupler is configured to change an incident angle that the light emits to the first holographic optical element. The second holographic optical element is located on the top surface of the waveguide element, and there is a first distance in a horizontal direction between the first holographic optical element and the second holographic optical element, in which the second holographic optical element is configured to diffract the light to the waveguide element below.