Abstract:
Systems, devices, and methods for eyebox expansion by exit pupil replication in wearable heads-up displays ("WHUDs") are described. A WHUD includes a scanning laser projector ("SLP"), a holographic combiner, and an optical splitter positioned in the optical path therebetween. The optical splitter receives light signals generated by the SLP and separates the light signals into N sub-ranges based on the point of incidence of each light signal at the optical splitter. The optical splitter redirects the light signals corresponding to respective ones of the N sub-ranges towards the holographic combiner effectively from respective ones of N spatially-separated virtual positions for the SLP. The holographic combiner converges the light signals to respective ones of N spatially-separated exit pupils at the eye of the user. In this way, multiple instances of the exit pupil are distributed over the area of the eye and the eyebox of the WHUD is expanded.
Abstract:
In one embodiment, a color holographic image is created by generating a separate complex hologram for each of multiple different colors of an object field illuminated with incoherent light, combining the separate complex holograms to obtain a color complex hologram, and generating a reconstructed color holographic image of the object field.
Abstract:
L'invention concerne un système d'enregistrement d'un hologramme numérique d'un objet (10) qui comprend : - une source cohérente (1) destinée à éclairer l'objet et ainsi produire une onde diffractée par l'objet, - un capteur numérique (12) destiné à enregistrer l'hologramme numérique de l'objet, Il comprend en outre un ensemble de modulation spatiale de phase (9, 15, 16, 17, 18) apte à produire dans le plan du capteur plusieurs répliques de l'onde diffractée par l'objet, décalées entre elles mais se recouvrant partiellement, ces répliques formant sur le capteur (12) un hologramme numérique dit auto-référencé (12') de l'objet.
Abstract:
Methods and apparatus for imaging a phase or amplitude that characterizes a scattered field emanating from a physical medium. A local probe is stepped to a plurality of successive probe positions and illuminated with an illuminating beam, while a specified phase function is imposed on a reference beam relative to the illuminating beam. A field associated with the scattered field is superimposed with the reference beam and the detection of both yields a detected signal which is recorded as a function of probe position in order to obtain a hologram. The holograph is transformed, filtered, and retransformed to generate an image. Alternatively, the illuminating beam may directly illuminate successive positions of the physical medium.
Abstract:
A method and apparatus for viewing or authenticating a diffractive device and a diffractive security device (1) are provided in which a first diffractive relief structure (200) is responsive to a first wavelength of visible monochromatic light, a second diffractive relief structure (200) is at least partially interlaced with the first diffractive relief structure (100) and responsive to a second wavelength of visible monochromatic light, and a third diffractive relief structure (400) is at least partially interlaced with the first and second diffractive relief structures (100, 200) and responsive to a third wavelength of visible monochromatic light. Under illumination by the first, second and third wavelengths of monochromatic light, the first diffractive relief structure (200) produces a first partial image of a first colour in a reconstruction plane, the second diffractive relief structure (300) produces a second partial image of a second colour in the reconstruction plane and the third diffractive relief structure (400) produces a third partial image of a third colour in the reconstruction plane, and the first, second and third partial images at least partially overlap in the reconstruction plane to form a multicoloured image. The diffractive security device may be used in a security document and the device may be authenticated by comparing the multicoloured image to a reference image.
Abstract:
Data is received as a serial optical stream which is applied to an optical storage medium (34) such as doped lithium niobate. As each data bit of the optical stream is applied to the optical storage medium (34) as an object beam (24), a reference beam (26) is also applied to create interference patterns or gratings in the storage medium (34). As subsequent data digits are applied, the angles at which the object beam (24) and reference beam (26) are applied are changed by rotating mirrors (28, 36) to create identifiable interference patterns in the optical storage medium (34) for each bit. The incoming optical data is optically recorded without a conversion between optical and electrical domains. The method and apparatus presented here provide continuous real-time storage of optical information in an optical form.
Abstract:
The present invention offers increased efficiency and quality in the duplication of a master hologram using contact printing methods using a single laser beam (33) from a single laser source (31). The improvement uses a polymer dispersed liquid crystal (PDLC) recording medium as the duplication blank (35) and/or the master hologram (37). The optical qualities of the PDLC recording medium allows the recording of highly complex optical patterns, such as computer generated hologram, without the need for multiple beam power/intensity balancing or long recording times. The contact printing method allows the recording of transmission hologram as well as the duplication of reflection holograms as shown in figure 4.
Abstract:
The invention relates to a method of suppressing image speckles in a holographic display screen, wherein illumination of the display screen occurs in the hologram in several individual steps and recording parameters are modified for each step. In this way, a holographic display screen providing a laser-detected and laser-illuminated hologram with a "speckle-free" image can be obtained. According to the application, the object screen can be recorded as a reflection or a transmission hologram.
Abstract:
光源からコヒーレント光を出射する光出射工程と、前記光源からの出射光に起因する物体波と参照波との干渉縞であるホログラムを検出器が撮像する撮像工程と、前記検出器に撮像させるホログラムを生成する照明光の波長を複数設定する波長設定工程とを含むディジタルホログラム生成方法において、観察対象となる構造について所定の演算手段により再生される実像及び共役像について、対応する実像に重畳したときにその視認を妨げないとして使用者により設定された共役像の拡大率Xに基き、前記波長設定工程にて設定する複数の波長を、その最短の波長λ min と最長の波長λ max とが、λ max /λ min ≧(1/X + 1)を満たすように設定する。