54 results about "Kinoform" patented technology

Stepped diffractive surfaces (13) are used to reduce variations in the optical properties of an optical system as a result of a change in the temperature of all or a portion of the system. Such surfaces have optothermal coefficients which differ from the optothermal coefficients of both kinoforms and refractive elements. Accordingly, stepped diffractive surfaces can be combined with such elements to achieve overall thermal control of optical systems employing such elements.

This invention relates to methods and apparatus for routing light beams in telecommunications devices using holographic techniques, in particular by displaying kinoforms on LCOS (Liquid Crystal on Silicon) devices. Thus we describe optical beam routing apparatus comprising: at least one optical input to receive an input beam; a plurality of optical outputs; a spatial light modulator (SLM) on an optical path between said optical input and said optical outputs; and a driver for said SLM to display a kinoform on said SLM to diffract said input beam into an output beam comprising a plurality of diffraction orders, wherein a routed one of said diffraction orders is directed to at least one selected said optical output; wherein said apparatus is configured to modify a wavefront of said output beam to reduce a coupling of said output beam into said selected optical output; and wherein said kinoform is adapted to compensate for said wavefront modification to compensate for said reduced coupling and thereby to reduce a coupling of other diffracted light from said input beam into others of said optical outputs than said at least one selected optical output.

The invention discloses a method for realizing varifocal lens based on a liquid crystal space optical modulator. The method comprises the following steps: according to the phase modulating principle of the liquid crystal space optical modulator, controlling the liquid crystal space optical modulator to modulate an incident light wave to generate a kinoform, diffracting the incident light wave into a converging spherical wave, and changing radius and zone number of a Fresnel zone plate in the kinoform to realize the variable focus of a program-control varifocus imaging system established by the liquid crystal space optical modulator. The method provided by the invention can be used for improving the automatic varifocus precision and the varifocus response speed of the varifocus imaging system, so that the focal distance of the lens is variable and easy to control.

The present invention discloses a multi-complex three-dimensional scene encryption and decryption method based on the kinoform and Fresnel domain multiplexing. The method comprises: starting from a complex three-dimensional scene characterized by a color image and a depth map, using a computational holography coding method to generate a computational kinoform that can be used for true three-dimensional reconstruction, wherein the kinoform shows random signal characteristics; superimposing the kinoform recording a single complex three-dimensional scene by using the Fresnel domain distance multiplexing method to generate a Fresnel diffraction distribution containing multiple three-dimensional scenes; and finally, using a phase template decomposition method for the diffraction signal and theinterference suppression signal which contain multiple three-dimensional scenes to obtain an encrypted and decrypted phase template. In order to suppress the speckle noise in the reconstructed three-dimensional scene, the multiplexed signal contains multiple kinoforms from the same three-dimensional scene, and the intensities of the light wave signals reconstructed by different kinoforms from thesame three-dimensional scene are averaged in the decryption phase to improve the quality of reconstruction. According to the method provided by the present invention, a three-dimensional scene can still be reconstructed in the case that the encrypted phase template suffers from large area shearing or is superimposed with a certain intensity of Gaussian noise, and the method has good security and robustness.

We describe a LCOS (liquid crystal on silicon) telecommunications light beam routing device, the device comprising: an optical input; a plurality of optical outputs; a LCOS spatial light modulator (SLM) in an optical path between said input and said output, for displaying a kinoform; a data processor, coupled to said SLM, configured to provide kinoform data for displaying said kinoform on said SLM; wherein said kinoform data defines a kinoform which routes a beam from said optical input to a selected said optical output; wherein said data processor is configured to input routing data defining said selected optical output and to calculate said kinoform data for routing said beam responsive to said routing data; and wherein said data processor is configured to calculate said kinoform data by: determining an initial phase pattern for said kinoform; calculating a replay field of said phase pattern; modifying an amplitude component of said replay field to represent a target replay field for said beam routing, retaining a phase component of said replay field to provide an updated replay field; performing a space-frequency transform on said updated replay field to determine an updated phase pattern for said kinoform; and repeating said calculating and updating of said replay field and said performing of said space-frequency transform until said kinoform for display is determined; and outputting said data for display on said LCOS SLM.

Disclosed is a two-dimensional code laser marking method and device based on a liquid crystal spatial light modulator. The device mainly comprises a laser device, a polarizer, beam expanding collimation systems, the liquid crystal spatial light modulator, a computer, focusing collimation systems and an imaging lens. Lasers emitted by the laser device pass through the polarizer to become polarized light, the polarized light passes through the beam expanding collimation systems to become parallel light, the parallel light is incident to the liquid crystal spatial light modulator, the liquid crystal spatial light modulator performs image information modulation on the parallel light, a two-dimensional code image output by two-dimensional code generating software generates a kinoform through the computer so as to precisely control a phase image displayed on the liquid crystal spatial light modulator, diffraction light splitting is performed on the parallel light through the image displayed on the liquid crystal spatial light modulator, and therefore the parallel light becomes diffraction light, the light beam of the diffraction light is narrowed and collimated through the focusing collimation systems, and finally the lasers are focused on a workpiece surface required to be marked through a flat-field lens.

An optical assembly for a projection illumination system has a refractive lenses and a diffractive lens for imaging a sheet of light from a light source onto a Spatial Light Modulator (SLM). One embodiment utilizes a fresnel lens having kinoforms formed on a surface. Such a lens may be molded using a light-weight plastic in a single step.

The invention discloses a design method of a diffractive optical element with high diffraction efficiency and low speckle noise. The design method comprises the following steps: 1) taking a complex amplitude light field of which the amplitude is a constant amplitude and the phase is a random phase as an initial complex amplitude light field on a kinoform surface; 2) spreading the complex amplitudelight field on the kinoform to an imaging surface through diffraction, and obtaining a complex amplitude light field on the imaging surface; 3) replacing the amplitude part of the complex amplitude light field obtained in the step 2) with specially designed PID limitation; 4) reversely diffracting and propagating the replaced complex amplitude light field in the step 3) back to the kinoform surface to obtain a complex amplitude light field; 5) taking out the phase part of the complex amplitude light field in the step 4), and quantifying the phase part to obtain the phase of a diffractive optical element; (6) taking the phase obtained in the step (5) as the phase of the kinoform surface, and taking the constant amplitude as the amplitude of the kinoform surface to obtain a complex amplitude light field of the kinoform surface, and (7) repeating the step (2) and the step (6), and completing iteration when the diffractive optical element meets the design requirements.

The invention discloses a color watermark preparation method based on kinoform. In the method, kinoform is applied in color watermark technology; compared with conventional color watermark technology, no reference light is led in during reproduction of kinoform, so that a single reproduction image can be acquired during reproduction; a random phase secret key is added, so that safety of watermark information is improved; due to own characteristics of kinoform, both robustness and safety can reach high level.

An optical pickup device enables prevention of an increase of spherical aberration during tracking without needing any finite optical system. The diameters of parallel light beams (A, B, C) for the next-generation DVDs, DVDs, and CDs are limited to diameters of a, b, c (a>b>c) in accordance with the NA for each type by a light beam limiting element, the diameter of light beam B is limited to the diameter ranges of b to c and d (=0.85×c) to e (d>e>0), the diameter of the light beam C is limited to the diameter ranges of c to d and less than e. They are passed through a phase correcting element (13B) and focused on the corresponding optical recording medium signal planes by means of a common objective lens. The objective lens is so optimized that the wave front aberration to the light beam A is minimum on the signal plane of the next generation DVD. The phase correcting element (13B) has a phase correcting zones (Z1 to Z4) of diffraction optical structure exhibiting a pseudo-kinoform shape of a step constitution. The spherical aberration to the light beam B is corrected in the zones (Z1, Z3). The spherical aberration to the light beam C is corrected in the zones (Z2, Z4). The light beam A is passed through all the zones of the light beam diameter a without changing the parallel light beam state by optimizing the step heights of the zones (Z1 to Z4).

The invention provides a method for synthesizing and optimizing a kinoform, wherein the method is based on a genetic algorithm. The technical scheme provided by the invention comprises the following steps: adding a group of random phase masks to original images; optimizing the masks; and when reaching optimizing conditions,taking the phase mask with minimum cost function as the best mask, and the corresponding kinoform of the best mask as the obtained kinoform. The Kinoforms are indirectly optimized by optimizing the masks. Ihe method, the error of reproduced images is reduced by directly optimizing the random phase masks so as to optimize the Kinoform. In the selection link of the genetic algorithm, an elite retaining method is used to retain excellent solutions of groups and to accelerate the convergence rate, and is easy for realizing. Compared with the traditional optimization method, the method provided by the invention has the advantages of small initial cost function, fast optimizing speed, good optimizing effect and the like.