4285results about "Diffraction gratings" patented technology

A metalens for focusing light is described. The metalens includes a library of elements for varying the propagating phase of the focusing light over at least a 2π radians range, where the library of elements is arranged in a sub-wavelength pattern that defines spacings between the elements. Each spacing exhibiting temperature-dependent spacing changes within a temperature range and each element in the library of elements includes: a refractive index exhibiting a temperature-dependency within the temperature range, a shape exhibiting a temperature-dependency within the temperature range, and a size exhibiting a temperature-dependency within the temperature range. The metalens also includes a phase profile defined by a combination of the refractive index, shape, and size of each element in the library, and the sub-wavelength pattern of the library of elements. The metalens also includes a focal length defined by the phase profile, the focal length exhibiting a temperature-dependency within the temperature range.

Methods, apparatus, devices, and systems for displaying three-dimensional objects by individually diffracting different colors of light are provided. In one aspect, an optical device includes: a first optically diffractive component including a first diffractive structure configured to diffract a first color of light having a first incident angle at a first diffracted angle, a second optically diffractive component including a second diffractive structure configured to diffract a second color of light having a second incident angle at a second diffracted angle, a first reflective layer configured to totally reflect the first color of light having the first incident angle and transmit the second color of light, and a second reflective layer configured to totally reflect the second color of light having the second incident angle. The first reflective layer is between the first and second diffractive structures, and the second diffractive structure is between the first and second reflective layers.

An eyepiece includes a planar waveguide having a front surface and a back surface. The eyepiece also includes a grating coupled to the back surface of the planar waveguide and configured to diffract a first portion of the light propagating in the planar waveguide out of a plane of the planar waveguide toward a first direction and to diffract a second portion of the light propagating in the planar waveguide out of the plane of the planar waveguide toward a second direction opposite to the first direction and a wavelength-selective reflector coupled to the front surface of the planar waveguide. The wavelength-selective reflector comprises a multilevel metasurface comprising a plurality of spaced apart protrusions having a pitch and formed of a first optically transmissive material and a second optically transmissive material disposed between the spaced apart protrusions.

The invention discloses a holographic sight based on a volume Bragg grating, and belongs to the field of holographic optics. The holographic sight comprises a sight housing, a semiconductor laser, a wave-locking element, a beam expander, an off-axis parabolic reflector and a holographic grating. The wave-locking element is a reflective volume Bragg grating, and the holographic grating is a transmissive volume Bragg grating. Both have excellent selectivity for the wavelength and incident angle of light. At the same time, both are made of photothermorefractive glass, which is less affected by the external temperature and can effectively reduce the deviation of the output wavelength, thereby reducing the deviation of the holographic grating mark image and increasing the accuracy and stability of the holographic sight. The photothermorefractive glass has a high refractive index modulation degree, which achieves a higher holographic diffraction efficiency, making the displayed holographic image brighter and more recognizable. In addition, the components of the beam expander and the off-axis parabolic reflector are used to shorten the optical path and reduce the overall structural size of the sight.

A method of fabricating a layered waveguide display comprises imprinting a surface-relief grating (SRG) on a first substrate, filling grating grooves of the SRG with a backfill material, depositing a first layer of an index-matching material on the SRG, and bonding the first layer of the index-matching material on the SRG to a first side of a second substrate. The first substrate and the SRG are characterized by a first refractive index and a second refractive index, respectively. The backfill material is characterized by a third refractive index greater than the first refractive index and the second refractive index. The index-matching material is characterized by a fourth refractive index greater than the first refractive index and the second refractive index. In some embodiments, the backfill material is the same as the index-matching material. The second substrate is characterized by a fifth refractive index matching the fourth refractive index.

A display system includes a replicator and a light control device 1000. The replicator receives spatially modulated light and replicates the light to form multiple replicas by waveguiding between a re

The invention relates to the technical field of optical element manufacturing, in particular to an exposure device with an adjustable interference angle without other optical elements, an exposure method and a preparation method of a reflective volume grating. The exposure device comprises a laser source, a reflector, a beam expanding system, a collimating lens, an optical rotating table and PTR glass, wherein the PTR glass is arranged on the optical rotating table; wherein laser emitted by the laser source passes through the reflector, is subjected to light spot beam expansion through the beam expansion system, and is subjected to light beam collimation through the collimating lens, and then the light beam enters the PTR glass body and is interfered in the PTR glass body to form interference fringes; by rotating the optical rotating table, a light beam is incident into the PTR glass body at different angles, and interference fringes of different periods are formed by changing the interference angle. The interference angle is changed by adjusting the light incident angle, the reflective volume grating with different wavelengths is prepared, interference can be automatically formed without depending on redundant optical components, and meanwhile the reflective volume grating has the advantages of being low in cost, simple in structure, easy to operate, beneficial to large-scale production and the like.

The invention belongs to the technical field of laser, and discloses a grating multiplexing spectrum synthesis system, which comprises a beamlet dense array, a diffraction grating and a turn-back mirror, each beamlet emitted by the beamlet dense array is diffracted by the diffraction grating and then is emitted in the form of convergent light, and the light is reflected twice by the turn-back mirror to form a light beam; each laser sub-beam is incident on the diffraction grating again along the opposite direction parallel to the original light, the sub-beams converge into one point on the diffraction grating by adjusting the distance between the turn-back mirror and the diffraction grating, and at the moment, the incident angle of each sub-beam is equal to the diffraction angle diffracted from the diffraction grating for the first time; and the diffraction angles of the sub-beams subjected to the second diffraction on the diffraction grating are equal and equal to the incident angle of the sub-beams subjected to the first diffraction, that is, the synthesized light beam is emitted along the direction parallel to and opposite to the direction of the light beam emitted from the sub-beam dense array. The invention provides a spectrum synthesis system which is simple in structure, easy in engineering implementation and compact in volume.

The invention belongs to the technical field of optical materials, and discloses a holographic polymer dispersed liquid crystal composition, a holographic grating and a preparation method. The composition comprises the following components in parts by mass: 0.5-1.5 parts of a photoinitiator, 2-5 parts of a co-initiator, 15-20 parts of a first monomer, 15-20 parts of a second monomer, 10-15 parts of a third monomer, 10-15 parts of a solvent and 10-20 parts of mixed liquid crystal. Wherein the first monomer is a monofunctional acrylic monomer, the second monomer is a bifunctional acrylic monomer, the third monomer is a polyfunctional acrylic monomer, the mixed liquid crystal comprises 10-25 wt% of a monomer liquid crystal and 75-90 wt% of a nematic liquid crystal, and the monomer liquid crystal contains fluorine as a benzene ring substituent and contains cyano or isothiocyano as an end group. Through cooperation of the monomer liquid crystal and the nematic liquid crystal in the mixed liquid crystal and cooperation of fluorine atoms and cyano / isothiocyano groups in the monomer liquid crystal, the holographic grating prepared from the composition has the characteristics of low haze and high diffraction efficiency, and the grating can be thinner, so that the requirements of light weight and clearness of AR glasses can be met.

The invention discloses a diffractive optical waveguide and augmented reality display equipment. The diffractive optical waveguide comprises a waveguide substrate and a first grating and a second grating which are arranged on the waveguide substrate, the first grating is configured to couple input light carrying image information into the waveguide substrate and enable the input light to be propagated through total reflection, and the second grating comprises a diffractive relief structure and is configured to at least carry out pupil expansion on the light propagated to the second grating; the diffraction optical waveguide further comprises an optical film layer, the optical film layer at least covers the second grating and comprises a filling structure, and the filling structure fills gaps in the diffraction relief structure of the second grating and forms an overflow layer higher than the diffraction relief structure. The refractive index of the filling structure is larger than that of the environment medium and smaller than that of the second grating. According to the embodiment of the invention, the transmittance of ambient light in the grating area can be effectively improved, and the difference between the grating area and the non-grating area is reduced, so that the overall visual experience is improved.

Provided is an image combiner including a waveguide, an input-coupling element, in an input-coupling area of the waveguide, configured to input light of a virtual image incident on the input-coupling area into the waveguide, and a folding / output-coupling element, in a folding / output-coupling area of the waveguide, configured to form an eye box by outputting the light input into the waveguide out of the waveguide, wherein the folding / output-coupling element is an anisotropic metasurface including a first sub-metasurface and a second sub-metasurface in a first sub-area and a second sub-area, and wherein the anisotropic metasurface is configured such that among rays input through different areas of the input-coupling area, a first ray having a first incidence angle is diffracted by the first sub-metasurface to be directed to the eye box and a second ray having a second incidence angle is diffracted by the second sub-metasurface to be directed to the eye box.

According to the device and the method for synchronously locking the phase and the period of the holographic interference fringes, two sets of locking devices are adopted and are respectively arranged at two ends of a holographic interference exposure field in the same direction as the period of the interference fringes, one set is used for compensating the phase of the interference light field to lock the phase of the interference fringes, and the other set is used for locking the period of the interference fringes. And the other one is used for compensating the output laser frequency of the laser to lock the interference fringe period. According to the interference fringe phase and period synchronous locking method, the problem that the contrast ratio of interference fringes is degraded due to phase and period drift of the interference fringes in the exposure process of a large-aperture holographic grating is solved, and particularly an interference fringe period real-time locking module is used; the problem that the fringe contrast is gradually deteriorated in the periodic direction due to periodic change of interference fringes is effectively solved, and a reliable solution is provided for preparation of the meter-scale large-aperture, high-contrast and high-uniformity holographic grating.

One embodiment provides an apparatus for displaying an image comprising: a first optical substrate comprising at least one waveguide layer configured to propagate light in a first direction, wherein the at least one waveguide layer of the first optical substrate comprises at least one grating lamina configured to extract the light from the first substrate along the first direction; and a second optical substrate comprising at least one waveguide layer configured to propagate the light in a second direction, wherein the at least one waveguide layer of the second optical substrate comprises at least one grating lamina configured to extract light from the second substrate along the second direction; wherein the at least one grating lamina of at least one of the first and second optical substrates comprises an SBG in a passive mode.

Gradient encapsulation of waveguide outcoupler gratings for control of diffraction efficiency and directionality includes a first grating formed over a substrate, the first grating having a plurality of first structures extending away from the substrate, the first grating corresponding to an outcoupler. The device includes a first encapsulant disposed in one or more gaps formed between adjacent first structures, where a fill ratio of the first encapsulant decreases along the first grating. Also described herein are methods for fabricating the device.

The invention relates to a (methyl) acrylate monomer as well as a preparation method and application thereof, the structural general formula of the (methyl) acrylate monomer is shown as G1, G2, G3 and G4: # imgabs0 #, and R1 is methyl or hydrogen. The whole (methyl) acrylate monomer provided by the invention is relatively small in molecular size, not easy to agglomerate, high in refractive index, liquid, low in viscosity and good in intermiscibility with other components.

Provided are an optical element capable of more easily detecting a change in refractive index of an object to be measured without sweeping a wavelength of incidence light, and an optical sensor using the optical element. An optical element includes a liquid crystal layer that is formed of a composition including a liquid crystal compound, in which the liquid crystal layer has a liquid crystal alignment pattern in which an orientation of an optical axis derived from the liquid crystal compound changes while continuously rotating toward at least one direction of in-plane directions, in a case where a length over which the orientation of the optical axis derived from the liquid crystal compound rotates by 180° in a plane is set as a single period, a length of the single period in the liquid crystal alignment pattern gradually changes in the one direction, and the liquid crystal layer has a resonance structure.

The invention discloses a far-field imaging system, a metasurface grating and an imaging terminal, and relates to the technical field of image generation. Dynamic environment compensation and imaging quality optimization are realized through cooperation of multiple modules of the system: the environment temperature is read in real time, the refractive index of the metasurface grating is corrected according to a pre-stored mapping relation, and a target wavefront function is constructed and dispersed to obtain an initial phase distribution matrix; dividing a focusing area in combination with a user sight line, and compensating and regulating a phase distribution matrix by voltage gradient; based on the divided buffer and background regions, a multi-region sampling rate is configured to generate a mask, and the collection efficiency of the key region is improved; monitoring far-field information change in real time, and selecting an interpolation or total variation strategy to update the image; by means of image definition feedback, a secondary phase correction term is superposed to optimize a phase distribution matrix; the problems of traditional far-field imaging in the aspects of environment adaptation, dynamic focusing, data acquisition and imaging quality are solved, and the method is suitable for augmented reality glasses and the like.

The invention provides a continuous depth gradually-changing grating structure based on a silicon carbide substrate and a preparation method thereof. The preparation method comprises the following steps: forming a sacrificial layer with gradually-changing thickness on the silicon carbide substrate; etching is carried out by adopting a two-step plasma etching process; and polishing the surface through a plasma polishing process. According to the invention, the gradient sacrificial layer is combined with two-step plasma etching, and a high-precision continuous depth gradient grating structure is realized on the silicon carbide substrate, so that the diffraction requirements of RGB three-color wavelengths are met; the micro-groove defect in the etching process is eliminated, the problem that the depth-to-width ratio and the surface quality cannot be considered in the traditional process is solved, and a key technical support is provided for mass production of the single-layer full-color optical waveguide; the transmission loss of the optical waveguide is reduced by controlling the surface roughness; and the product yield is improved, the production cost is reduced, and the method is suitable for large-scale production.

The invention provides a grating assembly and a manufacturing method of the grating assembly. The grating assembly comprises a substrate; the number of the optical cement auxiliary structures is multiple, and the multiple optical cement auxiliary structures are formed on the surface of one side of the substrate at intervals through nanoimprint; the functional layer covers the sides, away from the substrate, of the optical cement auxiliary structures in a shape follow-up mode so that the side faces and the top faces of the optical cement auxiliary structures can be wrapped by the functional layer, and gaps are reserved in the sides, away from the substrate, of the functional layer; the optical adhesive layer is arranged on the side, away from the substrate, of the optical adhesive auxiliary structure, and the projection of the optical adhesive layer on the substrate completely covers the optical adhesive auxiliary structure and the functional layer; the functional layer is a deposition layer, the grating assembly further comprises a plurality of diffraction gratings, and the diffraction gratings are filled in the gaps. The problem that the diffraction efficiency of a grating assembly in the prior art is difficult to improve is solved.

An image light guide for conveying a virtual image including a first surface and a parallel second surface, an in-coupling diffractive optic arranged along the first surface and / or the second surface, wherein the in-coupling diffractive comprises a first zone having a first set of diffractive features and a second zone having a second of diffractive features, and an out-coupling diffractive optic arranged along the first surface and / or the second surface, wherein the out-coupling diffractive optic comprises a first area having two or more zones and a second area having two or more zones. Wherein an imaginary axis is oriented along a centerline of the out-coupling diffractive optic, image-bearing light in-coupled into the waveguide by the first zone of the in-coupling diffractive optic is operable to propagate across the imaginary axis to the first area of the out-coupling diffractive optic, and image-bearing light in-coupled into the waveguide by the second zone of the in-coupling diffractive optic is operable to propagate across the imaginary axis to the second area of the out-coupling diffractive optic.

The invention discloses an external cavity tunable laser linewidth compression system for realizing wavelength phase locking based on mutual injection of gain chips. The external cavity tunable laser linewidth compression system comprises a red light semiconductor laser main gain chip, a first collimation optical system, a blazed grating, a tuning rotating mirror, a reflector, a power supply driving system and a double-path feedback amplification system, the double-path feedback amplification system comprises a first secondary gain chip, a second secondary gain chip, a second collimation optical system, a third collimation optical system and a polarization-free beam splitter prism; and the red light semiconductor laser main gain chip, the first secondary gain chip and the second secondary gain chip are all connected with the power supply driving system. Therefore, the technical problems of low output infrared light power, poor stability and narrow mode-hopping-free tuning range in the prior art are solved, and high-power, narrow-linewidth, high-stability and large-range mode-hopping-free continuous tuning red light output can be realized.

An optical system comprises a first lens group having positive refractive power, a second lens group having positive refractive power, and a third lens group having negative refractive power, arranged in order from an object side, wherein, when focusing, the second lens group moves along an optical axis, and the optical system satisfies the conditional expressions 0.100<BFa / f<0.500 and −5.000<(−G1R1) / f<500.000, where BFa is an air equivalent distance on the optical axis between a lens surface on an image side of a lens disposed closest to an image and the image, f is a focal length of the optical system, and G1R1 is a radius of curvature of a lens surface on the object side for a lens component disposed farthest on the object side in the first lens group.

The embodiment of the invention provides a grating structure, a light guide device and head-mounted display equipment. Wherein the grating structure comprises a plurality of grating units and filling materials, the grating units are periodically arranged at intervals, the space between the adjacent grating units is filled with the filling materials, and the filling materials cover the top surfaces of the grating units; wherein the grating unit has a first refractive index n1, the filling material has a second refractive index n2, and the grating structure meets the condition that the absolute value of the difference between n1 and n2 is smaller than or equal to 0.5. According to the grating structure provided by the embodiment of the invention, the diffraction efficiency of the diffraction behavior can be reduced through the new design of the grating structure, and rainbow lines are prevented from being formed in human eyes.

The invention discloses a preparation method of a polymer dispersed liquid crystal holographic grating with s polarization high diffraction characteristics, and belongs to the technical field of holographic optics. Raw materials comprise 60-90% of a thiol-ene monomer, 10-40% of liquid crystals, a photoinitiator accounting for 1.25% of the mass of the monomer, and a coinitiator accounting for 1.56% of the mass of the monomer. Light with the wavelength of 532 nm and the light intensity of 5-30 mW / cm < 2 > is used for carrying out double-interference photoetching to generate photochemical reaction so as to generate the polymer grating film, and the light is s polarized light. Under the optimal recording condition, delta n under s polarization can reach 1.93 * 10, and delta n under p polarization can reach 1.21 * 10. In combination with morphology analysis, it is found that refractive index modulation strongly depends on the proportion of a liquid crystal-rich phase to a polymer-rich phase in the grating. It is proved that the size of liquid crystal microdroplets formed by holographic recording is larger due to low recording intensity, and therefore the threshold driving voltage of the HPDLC grating is reduced.

The invention provides an acrylate monomer with a high refractive index and a preparation method and application thereof, the acrylate monomer has a structure as shown in a formula G1, G2 or G3, the refractive index of the acrylate monomer is 1.75 or above, so that a holographic recording medium has higher sensitivity and higher diffraction efficiency, and the holographic recording medium can be applied to the field of holographic recording. The holographic recording medium is used for a holographic grating, so that the holographic grating has high diffraction efficiency and high refractive index modulation degree.

The present invention discloses a privacy protection device and method based on physical light field modulation, which belongs to the field of optical devices and data security technology. In view of the problem that the existing privacy protection scheme relies on software algorithms, resulting in the risk of retaining original data, the device selectively attenuates the spatial frequency of the incident light field through an optical modulation unit, and implements irreversible destruction of high-frequency sensitive features (such as facial texture), while retaining low-frequency contour features (such as human body posture) to maintain machine vision functions. Users directly perceive that their privacy is protected through the optical phenomena of the physical appearance of the modulator (atomized surface, diffraction spot) without relying on electronic signal verification. This solution can effectively resist GAN data reconstruction attacks, is compatible with mainstream image sensors, and is suitable for scenarios such as smart security and medical image acquisition that require both privacy and machine vision.

The invention belongs to the technical field of flexible micro-nano optical element processing and information display / hiding, and discloses a surface structure color-based image processing method and a display / hiding state transition method thereof, and the method comprises the following steps: 1, predicting the pixel hue information of a displayed color picture through numerical calculation, calculating the wavelength value corresponding to a pixel, and calculating the pixel hue information according to the wavelength value; cutting process parameters corresponding to cutting pixels on the surface of the metal mold are determined according to the flexible material stretching rate and the grating parameters; 2, an elliptical vibration cutting process is adopted, a designed grating structure is machined on the surface of the metal mold to serve as a mother set, and a metal surface micro / nano structure is reprinted through a flexible material monomer polymerization curing process; and step 3, adjusting and controlling the wavelength of the structured light by stretching the flexible optical element and changing the spacing of the gratings, realizing the change of the structured light from a visible range to an invisible / invisible visible range, and realizing the display / hidden state conversion of an image. According to the method provided by the embodiment of the invention, the display / hidden state conversion of the color image on the surface of the flexible optical element is successfully realized.

The invention relates to the technical field of optical materials and nano structures, in particular to an ultraviolet broadband light absorber based on graphene and a multi-layer periodic structure. The structure of the ultraviolet broadband light absorber sequentially comprises a graphene layer, a distributed Bragg reflection grating structure layer and a SiO2 substrate at the bottom from top to bottom. The preparation process of the ultraviolet broadband light absorber comprises the following steps: preparing the graphene layer; a SiO2 layer is deposited; depositing a TiO2 layer; carrying out multi-layer superposition; adding a graphene layer; and completing the device. The light absorption efficiency of graphene in the ultraviolet band is greatly improved, broadband efficient absorption within the wavelength range of 240-370 nm is achieved, the highest absorption rate can reach 99.75%, the absorber is not sensitive to polarization, the preparation process is simple, and technical support is provided for design of the efficient ultraviolet absorber.

To allow systems for manufacturing waveguide cells in accordance with various embodiments to be configured and implemented in many different ways.SOLUTION: In many embodiments, various deposition mechanisms are used to deposit a layer(s) of an optical recording material(s) onto a transparent substrate. A second transparent substrate can be provided, and the three layers can be laminated to form a waveguide cell. A suitable optical recording material can vary widely depending on a given application. In some embodiments, the optical recording material deposited has a similar composition throughout a layer. In a number of embodiments, the optical recording material spatially varies in composition, enabling formation of optical elements with varying characteristics. Regardless of the composition of the optical recording material, any method of placing or depositing the optical recording material onto a substrate can be utilized.SELECTED DRAWING: Figure 11

The invention relates to a (methyl) acrylate monomer as well as a preparation method and application thereof, the structural general formula of the (methyl) acrylate monomer is shown as G1, G2 and G3: # imgabs0 #, r2 and R3 are selected from hydrogen, Br, phenyl, methyl or # imgabs 1 #, wherein A1 in the # imgabs 2 # is phenyl or methyl. According to the (methyl) acrylate monomer provided by the invention, the molecular size of the whole monomer is relatively small, agglomeration is not easy to occur, and the (methyl) acrylate monomer has a high refractive index.