Disclosed are methods and systems for displaying images, and for implementing volumetric user interfaces. One exemplary embodiment provides a system comprising: a light source; an image producing unit, which produces an image upon interaction with light approaching the image producing unit from the light source; an eyepiece; and a mirror, directing light from the image to a surface of the eyepiece, wherein the surface has a shape of a solid of revolution formed by revolving a planar curve at least 180 around an axis of revolution.

An illumination device is provided, including a coherent light source that emits coherent light beam and an optical device that diffuses the coherent light beam. The optical device includes a first diffusion region that diffuses the coherent light beam to illuminate a first area, and a second diffusion region that diffuses the coherent light beam to display predetermined information in a second area. A timing control unit individually controls a light emission timing at which the coherent light source emits the coherent light so that the coherent light is irradiated to the first diffusion region and the second diffusion region, an incident timing at which the coherent light from the coherent light source is incident on the first diffusion region and the second diffusion region, or an illumination timing at which the coherent light diffused by the optical device illuminates the first area and the second area.

A backlight unit for a binocular-holographic display device and a holographic display device including the same are provided. The backlight unit includes a light source unit which outputs light, a first beam expansion unit which expands, in a first direction, the light output from the light source unit, a second beam expansion unit which expands, in a second direction perpendicular to the first direction, the light output from the first beam expansion unit, and a beam deflection unit which diffracts light incident on the first beam expansion unit. The holographic display device includes the backlight unit, a field lens, and a spatial light modulator.

A printing device (106) includes a laser source and a LCOS-SLM (Liquid Crystal on Silicon Spatial Light Modulator). The printing device generates a laser control signal and a LCOS-SLM control signal. The laser source (110) generates a plurality of incident laser beams based on the laser control signal. The LCOS-SLM (112) receives the plurality of incident laser beams, modulates the plurality of incident laser beams based on the LCOS-SL M control signal to generate a plurality of holographic wavefronts (214,216) from the modulated plurality of incident laser beams. Each holographic wavefront forms at least one corresponding focal point. The printing device cures a surface layer or sub-surface layer (406) of a target material (206) at interference points of focal points of the plurality of holographic wavefronts. The cured surface layer of the target material forms a three-dimensional printed content.

A laser beam (L50) is reflected by a light beam scanning device (60) and irradiated onto a hologram recording medium (45). On the hologram recording medium (45), an image (35) of a linear scatter body is recorded as a hologram by using reference light that converges on a scanning origin (B). The light beam scanning device (60) bends the laser beam (L50) at the scanning origin (B) and irradiates the laser beam onto the hologram recording medium (45). At this time, by changing a bending mode of the laser beam with time, an irradiation position of the bent laser beam (L60) on the hologram recording medium (45) is changed with time. Diffracted light (L45) from the hologram recording medium (45) produces a reproduction image (35) of the linear scatter body on a light receiving surface (R) of the stage 210. When an object is placed on the light receiving surface (R), a line pattern is projected by hologram reproduction light, so that the projected image is captured and a three-dimensional shape of the object is measured.

A light detection and ranging, LiDAR, system arranged to make time of flight measurements of a scene. The LiDAR system comprises a holographic projector comprising: a spatial light modulator arranged to display light modulation patterns, each light modulation pattern comprising a hologram and a grating function having a periodicity; a light source arranged to illuminate each displayed light modulation pattern in turn; and a projection lens arranged to receive spatially modulated light from the spatial light modulator and project a structured light pattern corresponding to each hologram onto a respective replay plane. The LiDAR system further comprises a system controller arranged to receive distance information related to the scene and output to the holographic projector a control signal corresponding to the distance information. The holographic projector is arranged to use the control signal to determine a parameter for projection of a subsequent structured light pattern.

A beam deflection apparatus includes a first beam deflector that deflects light in a first direction and a second beam deflector that deflects light in a second direction perpendicular to the first direction, wherein the first beam deflector and the second beam deflector each include a first region for deflecting light of a first wavelength and a second region for deflecting light of a second wavelength, and a ratio of a spatial period of a signal applied to first drive electrodes arranged in the first region of the first beam deflector to the first wavelength is the same as a ratio of a spatial period of a signal applied to second drive electrodes arranged in the second region of the first beam deflector to the second wavelength.

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.

An acousto-optic device capable of increasing a range of a diffraction angle of output light by using a nanostructured acousto-optic medium, and an optical scanner, an optical modulator, a two-dimensional/three-dimensional (2D/3D) conversion stereoscopic image display apparatus, and a holographic display apparatus using the acousto-optic device. The acousto-optic device may include a nanostructured acousto-optic medium formed by at least two different mediums repeatedly alternating with each other, wherein at least one of the at least two different mediums includes an acousto-optic medium. The acousto-optic device having the aforementioned structure may increase the range of a diffraction angle of output light. Thus, various systems such as the optical scanner, the optical modulator, the 2D/3D conversion stereoscopic image display apparatus, and the holographic display apparatus may not require a separate optical system to increase an operational angle range, thereby decreasing a size of the system and/or improving a resolution of the system.

A backlight unit for a binocular-holographic display device and a holographic display device including the same are provided. The backlight unit includes a light source unit which outputs light, a first beam expansion unit which expands, in a first direction, the light output from the light source unit, a second beam expansion unit which expands, in a second direction perpendicular to the first direction, the light output from the first beam expansion unit, and a beam deflection unit which diffracts light incident on the first beam expansion unit. The holographic display device includes the backlight unit, a field lens, and a spatial light modulator.