A holographic projector having an optical path is described. The holographic projector comprises a first spatial light modulator arranged to display a first hologram, and a first light source. The first light source is arranged to illuminate the first spatial light modulator with light of a first wavelength such that a first holographic reconstruction corresponding to the first hologram is formed on a replay plane. The holographic projector further comprises a continuous block of transparent material. At least part of the optical path is formed through the continuous block of transparent material. The transparent material has a refractive index greater than air.

A holographic imaging device includes a laser device, a laser beam expanding and collimating system and a liquid crystal cell. The laser beam expanding and collimating system is configured to expand a light beam from the laser device and enable the expanded light beam to be transmitted substantially vertically to the liquid crystal cell. An amplitude-transmission coefficient distribution of the liquid crystal cell is determined in accordance with a brightness distribution of holographic interference fringes of an object to be displayed.

Light-emitting devices for motor vehicles are provided, which comprise a reflection hologram. A light-guiding body is provided to direct light from a light source arrangement onto the hologram.

A device including a light source, an image sensor, and a holder defining two positions between the light source and the image sensor. Each position is able to receive an object with a view to its observation. An optical system is placed between the two positions. Thus, when an object is placed in a first position, it may be observed, through the optical system, via a conventional microscopy modality. When an object is placed in the second position, it may be observed via a second lensless imagery modality.

There is herein defined optics (e.g. an array of optics) forming an optical beam to either produce a collimated or diverging/converging beam emerging from a virtual source point to illuminate a hologram. There is also described an optical beam illuminating a reflection hologram from the front and a further configuration where an optical beam combined with a holographic optical element (HOE) minor enables rear illumination of a reflection hologram.

A backlight unit includes: a light source unit which outputs coherent light; a first reflection unit including a parabolic mirror; a second reflection unit facing the first reflection unit and including a flat mirror; and a holographic optical element which changes a path of incident light, where a reflection surface of the second reflection unit forms an acute angle with an light incident surface of the holographic optical element, and the coherent light output from the light source unit sequentially passes the first reflection unit, the second reflection unit, and the holographic optical element.

Embodiments described herein relate to a large area lens-free imaging device. One example is a lens-free device for imaging one or more objects. The lens-free device includes a light source positioned for illuminating at least one object. The lens-free device also includes a detector positioned for recording interference patterns of the illuminated at least one object. The light source includes a plurality of light emitters that are positioned and configured to create a controlled light wavefront for performing lens-free imaging.

A device including a light source, an image sensor, and a holder defining two positions between the light source and the image sensor. Each position is able to receive an object with a view to its observation. An optical system is placed between the two positions. Thus, when an object is placed in a first position, it may be observed, through the optical system, via a conventional microscopy modality. When an object is placed in the second position, it may be observed via a second lensless imagery modality.

A display method lets a display beam to propagate in a transparent substrate while internally reflected repeatedly and lets the display beam partly emit out of the transparent substrate every time the display beam is internally reflected, thereby emitting display beams from almost entirety of a surface of the transparent substrate. The display beam is produced holographically. A display apparatus includes a spatial phase modulator that produces a display beam, a transparent substrate in which the display beam is internally reflected repeatedly to propagate in it, and a splitter that lets the display beam partly emit out of the transparent substrate every time the display beam is internally reflected.

A display device includes a light source part including a first light source and a second light source, a collimation lens that collimates light incident from the light source part, a wave guide that guides and diffracts the light incident from the collimation lens, a spatial light modulator that modulates the light passing through the wave guide so as to form a holographic pattern for reproducing a holographic image, a focusing optical system that focuses the holographic image on a space, and a light separating plate disposed between the light source part and the collimation lens, the light separating plate separating light of the first light source and light of the second light source from each other.