1772results about "Diffraction gratings" patented technology

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 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 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 relates to an optical monomer and a preparation method and application thereof, the structural general formula of the optical monomer is as follows: R1, R2 and R3 are respectively selected from one of hydrogen and C1-C4 alkyl, A1 is selected from one of hydrogen and C1-C4 alkyl, and A2 is C1-C4 alkyl; r4 is selected from one of H, phenyl and C1-C4 alkyl, and A2 is C1-C4 alkyl; and R5 is hydrogen or methyl. The optical monomer provided by the invention contains a (methyl) acrylate group, and has the properties of high refractive index and low volume shrinkage; and a plurality of aromatic rings with high molar refractive index and low molar volume are contained, so that the whole molecule of the whole monomer is extremely high in refractive index. The monomer structure provided by the invention has a plurality of branched chains, the overall molecular weight is small, and the molecules are not easy to agglomerate.

The invention discloses a photovoltaic ecological system based on a holographic frequency division technology. The photovoltaic ecological system comprises a frame body; the frequency-division concentrating photovoltaic unit comprises a substrate layer which is formed by connecting a heat conducting plate and a dodging plate and is connected with the frame body through a reciprocating motion mechanism, a concentrating layer and a holographic grating layer which are sequentially arranged above the heat conducting plate, and a photoelectric conversion battery arranged on the heat conducting plate; the light adjusting unit is arranged between the two adjacent frequency division concentrating photovoltaic units and comprises two frequency division plates connected through a rotating pair, and the ends, away from each other, of the two frequency division plates are connected with the corresponding frequency division concentrating photovoltaic units through rotating pairs; the reflective optical baffles are arranged on the two sides of the substrate layer, and side wall batteries are further arranged on the sides, close to the light adjusting units, of the reflective optical baffles. According to the invention, through a spectrum frequency division and space light energy distribution mechanism, multi-band efficient utilization of sunlight is realized, the light quality and the light quantity required by plant photosynthesis are guaranteed, and the photovoltaic power generation efficiency is improved.

The invention provides a volume holographic grating exposure parameter determination method and a two-dimensional pupil expansion volume holographic optical waveguide, and the method comprises the steps: carrying out the multiple rotation of a vector of a first light beam, a vector of a second light beam and a holographic photosensitive material when the wavelengths of the first light beam and the second light beam are first recording wavelengths, the rotated vectors of the first light beam and the second light beam and the rotated material position of the holographic photosensitive material are obtained; converting the wavelengths of the first light beam and the second light beam into a second recording wavelength, and rotating the rotated vectors of the first light beam and the second light beam at least once to obtain in-material vectors of the first light beam and the second light beam; determining the in-air vectors of the first light beam and the second light beam according to the in-material vectors of the first light beam and the second light beam; and determining incident angles of the first light beam and the second light beam according to the in-air vectors of the first light beam and the second light beam. According to the method, the manufacturing efficiency of the two-dimensional pupil-expanding body holographic optical waveguide comprising the coupling-in, turning and coupling-out body holographic grating can be improved.

The present invention relates to a transmission grating and a preparation method therefor. The transmission grating comprises: a substrate, which has a first surface; a grating layer, which comprises trapezoidal grating teeth arranged in an array on the first surface, wherein the grating teeth extend in the direction of thickness of the substrate, and a gap is provided between two adjacent grating teeth; and a dielectric layer, which is arranged on a surface of the grating layer and fills the gaps, wherein the dielectric layer has a second surface on the side thereof away from the substrate; there is a difference between the height of the grating teeth and the distance between the second surface and the first surface, the difference being m; and incident light passes through the interior of the grating layer and is incident towards the second surface. By means of the design of a film layer structure and film layer dimensions of the transmission grating, the present invention can acquire transmission gratings having different diffraction efficiencies and polarization degrees, and can accurately control the dimensions of the film layer structure of the transmission grating during machining, thereby facilitating machining.

An optical system is presented for use in a near-eye mixed reality system. The system comprises a relay system defining an eyebox of the optical system, said relay system being configured and operable to relay a virtual image light field from a light-engine onto an eye pupil plane while combining said virtual image with real-world light field. The relay system is configured as a free space relay system configured for free space propagation of said virtual image light field being relayed, said free space relay system comprising at least one off-axis 4f-system. Each of said at least one off-axis 4f-system comprises at least one lens formed from at least one resonance-domain surface relief diffractive optical element (SRDOE) operable for combining said virtual image light field with the real-world light field, said at least one SRDOE being configured with a predetermined global surface relief pattern characterized by global variation of at least some of pattern parameters across said SRDOE.

The invention relates to a bottom alignment grating preparation method and a bottom alignment grating, and the bottom alignment grating preparation method comprises the steps: depositing a grating material on a light-transmitting substrate, so as to form a grating material layer on the light-transmitting substrate; etching the grating material layer to form a plurality of grating areas with different heights on the grating material layer; and respectively etching each grating area to the light-transmitting substrate to form a plurality of groups of gratings with different heights so as to obtain a bottom-aligned grating. The partition structure of each grating area of the bottom-aligned grating is bottom-aligned, so that the optical efficiency of an optical device can be improved, and an optical film interference effect caused by a residual film is reduced. The bottom alignment grating can be prepared through the preparation method of the bottom alignment grating provided by the invention.

The invention discloses a U-shaped groove grating ion beam etching method based on a mask shadow effect, and relates to the technical field of U-shaped groove etching, and the method comprises the steps: placing a substrate with a photoresist grating mask in an inclined manner, and enabling an ion beam to bombard the photoresist grating mask in an inclined incidence manner; through a shadow effect generated by a photoresist grating mask on an ion beam, the etching dose distribution of different areas on the surface of a substrate is regulated and controlled, so that the etching dose of the central area of the groove bottom is greater than that of the areas on the two sides, and the U-shaped groove with a smooth and gradually-changed bottom contour is directly etched and formed. By constructing the smooth transition U-shaped groove bottom structure, sharp edges and corners are thoroughly eliminated, and the phenomenon of electric field concentration is remarkably relieved, so that the damage risk under high-power laser irradiation is effectively reduced, the stability of the grating in an extreme environment is improved, and the service life of the grating in the extreme environment is prolonged.

The invention discloses a femtosecond laser direct-writing Type X structure-based geometric phase fork-shaped grating, a preparation method and application of the femtosecond laser direct-writing Type X structure-based geometric phase fork-shaped grating in vortex light, and belongs to the technical field of laser processing, and the femtosecond laser direct-writing Type X structure-based geometric phase fork-shaped grating comprises design and parameter calculation of a geometric phase fork-shaped grating device, determination of a processing parameter window of a Type X structure and the femtosecond laser direct-writing fork-shaped grating. According to the invention, femtosecond laser is utilized to induce and generate an anisotropic nanopore structure with ultra-high transmittance higher than 97% in fused quartz and other transparent materials, namely a Type X structure, the structure has a birefringence characteristic, and the slow axis angle of the structure is always perpendicular to the laser polarization direction, so that the slow axis angle can be continuously adjusted by adjusting laser polarization. The Type X structure serves as a metasurface unit of the geometric phase fork-shaped grating, geometric phase regulation and control are achieved by controlling slow axis orientation of the Type X structure, and therefore generation and regulation and control of vortex light are achieved. The method is high in efficiency and simple in process.

The invention discloses a polarization sensitive type broadband absorber based on metal-medium stacking, and relates to the technical field of micro-nano photonic devices and infrared detection. The absorber sequentially comprises a bottom-layer high-loss metal reflecting layer, a multi-layer stacked composite dielectric cavity structure and a top-layer sub-wavelength metal grating from bottom to top, according to impedance matching and interference resonance theories, a broadband absorption substrate is constructed through a multi-layer film structure at the bottom, and light energy is converted into heat energy by utilizing the high loss characteristic of bottom layer metal; plasmon resonance is excited through the top metal grating, the coupling efficiency of TM polarized light is enhanced, and TE polarized light is cut off; the above structural design successfully realizes efficient broadband absorption and high polarization extinction ratio in an infrared band. The structure is simple in design, is compatible with a CMOS technology, and has excellent wide-angle stability. And meanwhile, polarization screening can be realized without an external polaroid, and miniaturization and integration of an infrared detection system are facilitated.

The invention provides a photopolymer system, a grating device containing a chirp structure and a preparation method of the grating device. Visible light and ultraviolet light dual initiators and azobenzene polymerizable acrylate monomers are introduced into the photopolymer system; by utilizing the characteristics that an acrylate group can be used as a writing monomer to participate in a copolymerization process and an azobenzene group can be subjected to continuous photoisomerization during holographic exposure, a visible light photoinitiator and an ultraviolet light initiator driving system are reacted and cross-linked in sequence; a chirp structure is induced to be generated in the formed volume holographic grating while the photopolymer system records interference fringes, so that grating period change caused by material shrinkage is effectively compensated, the angle response bandwidth of the grating is remarkably widened, the requirement for refractive index modulation of the photopolymer system is reduced, and the optical grating has a wide application prospect. According to the invention, the selection range of the photopolymer system is widened, the overall aging resistance of the material system is improved, and the service life of the grating device is prolonged.

The invention relates to a reactive ion beam etching method of a large-size diffractive optical element and a vacuum etching machine. The method comprises the following steps: in a reactive ion beam main etching stage, a main ion source emits a high-energy main etching reactive ion beam to scan and etch the whole surface of the large-size diffractive optical element; in a selective area reaction ion beam ashing stage, an auxiliary ion source is controlled to emit a low-energy ashing reaction ion beam, and scanning ashing processing is carried out on a central effective area of the large-size diffractive optical element; in the reaction ion beam edge removal stage, the auxiliary ion source is controlled to emit edge removal reaction ion beams with set process parameters, and edge thickening photoresist of the large-size diffractive optical element is removed; and taking out the large-size diffraction optical element finished product after etching is completed. According to the technical scheme, the production cost of reactive ion beam etching of the large-size diffractive optical element can be reduced, and the production efficiency can be improved.

The invention provides a half-leaf type double-layer multi-leaf grating structure, and relates to the technical field of multi-leaf collimators, the half-leaf type double-layer multi-leaf grating structure comprises two leaf frames, the two leaf frames are respectively provided with an upper-layer leaf group and a lower-layer leaf group, the upper-layer leaf group comprises a plurality of upper leaves, the lower-layer leaf group comprises a plurality of lower leaves, and the upper-layer leaf group comprises a plurality of lower leaves. The projection width of each upper blade and each lower blade on an isocenter plane is 0.5 cm, the number of the upper blades is the same as that of the lower blades, the total number of the blades of the upper-layer blade group and the lower-layer blade group is half of the number of the blades of a traditional double-layer grating, and the upper blades and the lower blades are arranged on the isocenter plane in a staggered mode. The difference between the center line of the upper blade and the center line of the lower blade on the isocenter plane is 0.5 cm, and the thickness of each upper blade and the thickness of each lower blade are designed to be positive tolerance, so that when the blades are closed, the adjacent blades on the upper layer and the lower layer form a shielding overlapping area in the beam direction, ray leakage is prevented, and the number of the blades and the system complexity are reduced.

The invention provides an off-axis illumination photoetching mask, a preparation method thereof and a photoetching system, which can be applied to the technical field of micro-nano machining and advanced photoetching, and the photoetching mask comprises a mask substrate comprising a first surface and a second surface which are oppositely arranged; the photoetching mask pattern structure is located on the second surface of the mask substrate; the light incident part is located on the first surface of the mask substrate, and the light incident part comprises a plurality of light incident units which are periodically arranged; wherein the light incident unit is provided with a V-shaped structure in the direction perpendicular to the first surface, the V-shaped structure gradually shrinks inwards from the first surface to the second surface, and each V-shaped structure comprises two slope surfaces which are connected with each other; the light incident part further comprises a band-pass filtering film which at least covers the two slope faces of the V-shaped structure.

The utility model discloses a diffraction optical waveguide, which comprises a waveguide substrate, the waveguide substrate at least comprises a coupling-in area, a first coupling-out area and a second coupling-out area, and the first coupling-out area and the second coupling-out area are respectively used for corresponding to a left eye and a right eye of a human eye, the first coupling-out area, the coupling-in area and the second coupling-out area are sequentially arranged in the first direction, and the size of the coupling-in area in the first direction is matched with the size of a projection light spot on a coupling-in plane in the first direction. The size of the coupling-in area in the second direction is larger than the size of a projection light spot on the coupling-in plane in the second direction, and the first direction is orthogonal to the second direction. The diffraction optical waveguide provided by the utility model can be compatible with an optical machine installation position in a certain range.

Methods of manufacturing an optical device can include, in some implementations, providing a substrate having a first polymeric layer on a surface of the substrate and a second polymeric layer on the first polymeric layer, forming first openings in the second polymeric layer to define an etch mask composed of material of the second polymeric layer, and etching to form second openings in the first polymeric layer, wherein locations of the second openings are defined by the etch mask. A material is deposited in the second openings to form meta-atoms of a first metastructure, wherein adjacent ones of the meta-atoms are separated from one another by polymeric material of the first polymeric layer. Optical devices including metastructures can be formed, where meta-atoms of the metastructure have a relatively high aspect ratio.

The invention relates to a small-sized light-weight large-target-surface infrared athermalization optical system, and the optical system consists of a first meniscus positive lens, a meniscus negative lens, a second meniscus positive lens and a third meniscus positive lens which are sequentially and coaxially arranged from an object side to an image side, the second meniscus positive lens and the third meniscus positive lens are the same lens, the first meniscus positive lens, the second meniscus positive lens and the third meniscus positive lens are all made of chalcogenide glass IRG206, and the optical system ensures that edge imaging is clear and the image surface diameter reaches 20mm through optimal arrangement of focal power and optical materials of all the lenses and intervals among all the lenses, so that the image quality is improved. The long-wave infrared imaging device can adapt to a 1280 * 1024 array and a long-wave uncooled infrared detector with the pixel size of 12 microns, and has the advantages of high imaging quality, small size and light weight.

The invention provides a polymer composition, a polymer film material, a holographic grating, a preparation method of the holographic grating, an optical film material and display equipment. The polymer composition comprises a first polymerizable monomer, a second polymerizable monomer and a film-forming resin. The first polymerizable monomer is a non-liquid crystal monomer; the second polymerizable monomer is a liquid crystal monomer, the second polymerizable monomer comprises an active group, and the second polymerizable monomer can be subjected to a copolymerization reaction with the first polymerizable monomer through the active group under illumination. The refractive index modulation degree of the optical film material can be improved by using the polymer composition.

The described embodiments provide a waveguide combiner with a phase matching region. The waveguide includes one or more gratings. Comprising a grating structure is disposed over the waveguide substrate. A phase matching region is disposed over the waveguide substrate between the one or more gratings and the waveguide region. The phase matching region includes a waveguide layer having a thickness that varies from a first end to a second end of the waveguide layer; or a plurality of structures having a depth therebetween. One or more of the depths differ from each other, or at least two or more of the plurality of structures have a first duty cycle that differs from a second duty cycle of the plurality of structures.

The invention relates to the technical field of holographic gratings, in particular to a holographic grating with a high refractive index modulation degree and a preparation method thereof, and the preparation method comprises the steps: coating a grating substrate with a precursor material to form a coating, and preparing a holographic dry plate with a holographic material layer; performing interference exposure on the holographic plate to obtain a semi-finished grating; bleaching the semi-finished product grating, and soaking the semi-finished product grating in an extraction liquid to obtain a grating precursor with a groove; and filling the groove with a fluorine-containing polymer dopant to obtain the holographic grating. The part, corresponding to the exposure bright area, of the grating precursor with the grooves is a polymer with a high refractive index, the inert body in the exposure dark area is removed, air is left, the grooves are formed in the surface of the grating, the appearance of the grooves fluctuates, the grooves are filled with low-refractive-index substances, and finally the high-refractive-index substances in the bright area are formed. The dark area is of a grating structure made of a low-refractive-index material; by adopting a two-step processing method, the holographic grating without light leakage in the reverse direction can be manufactured.

The invention discloses an optical monomer, a holographic recording medium, a preparation method and a related device, the structural general formula of the optical monomer is as shown in G1-G6, the monomer is high in refractive index, the preparation method is simple, and further, the optical monomer with the structure is introduced into the photopolymer type holographic recording medium, so that the photopolymer type holographic recording medium is prepared. The invention further provides a preparation method of the holographic recording medium, a volume holographic grating containing the holographic recording medium, a holographic optical element containing the holographic recording medium and an optical device containing the holographic recording medium.

An eyewear display device implements a curved lightguide to form an intermediate image between an incoupler and an outcoupler. The curved lightguide produces an approximately 20-degree diagonal field of view (FOV) full-color display having approximately 10% red, blue, green efficiency with uniform color and luminance for a micro-display at a temple of an eyewear display device. The curved lightguide incorporates freeform mirror incouplers and / or outcouplers and color-corrected relay optics. Using an intermediate image stage in the optical pathway allows for use of a compact incoupler that does not exceed a thickness of the curved lightguide.

The invention relates to the technical field of gratings, and discloses a polarization holographic two-dimensional grating and a preparation method thereof, an optical waveguide and a two-dimensional pupil expansion method, and the method comprises the steps: forming a light-operated orientation layer film on a substrate; exposing the light-operated orientation layer film to obtain an oriented light-operated orientation layer; coating the photo-alignment layer with a liquid crystal polymer solution mixed with a chiral agent and an initiator to form a liquid crystal polymer film; and curing the liquid crystal polymer film to obtain the polarization holographic two-dimensional grating. Therefore, a two-dimensional grating can be directly prepared without depending on multi-area grating combination to realize bidirectional expansion of light beams, the view field range is expanded, the technological process is simplified, the manufacturing complexity and the preparation cost are reduced, and meanwhile, the consistency and high performance of mass production are guaranteed; in addition, the integrated design of the two-dimensional grating can avoid the problem of uneven brightness caused by traditional multi-assembly splicing, the overall brightness uniformity and the imaging display effect are effectively improved, and a low-cost and high-performance implementation path is provided for optical waveguide two-dimensional pupil expansion.

Provided in the present application are an exposure parameter determination method and apparatus for a volume holographic grating, and a two-dimensional exit pupil expansion volume holographic optical waveguide. The method comprises: when the wavelengths of a first light beam and a second light beam are a first recording wavelength, rotating a vector of the first light beam, a vector of the second light beam, and a holographic photosensitive material multiple times, so as to obtain rotated vectors of the first light beam and the second light beam, and a rotated material position of the holographic photosensitive material; shifting the wavelengths of the first light beam and the second light beam to a second recording wavelength, and rotating at least once the rotated vectors of the first light beam and the second light beam, so as to obtain in-material vectors of the first light beam and the second light beam; on the basis of the in-material vectors of the first light beam and the second light beam, determining in-air vectors of the first light beam and the second light beam; and on the basis of the in-air vectors of the first light beam and the second light beam, determining the incident angles of the first light beam and the second light beam. The method can improve the manufacturing efficiency of a two-dimensional exit pupil expansion volume holographic optical waveguide including coupling-in, turning and coupling-out volume holographic gratings.

An optical device for a head-mounted display device includes a first partial reflector and a second partial reflector positioned relative to the first partial reflector so that the second partial reflector receives first light transmitted through the first partial reflector and reflects at least a portion of the first light toward the first partial reflector as second light. At least a portion of the second light is reflected by the first partial reflector as third light, and at least a portion of the third light is transmitted through the second partial reflector. At least one of the first partial reflector or the second partial reflector includes a reflective holographic element.

An ophthalmic multifocal lens is presented, configured to provide distance vision and at least one other usable visual acuity. The lens comprises a translucent lens body having an optical axis and a refractive baseline, the refractive baseline extending to at least a portion of the lens body, and a diffraction grating configured to act as an optical splitter, extending concentrically in the radial direction and superimposed on at least a portion of the refractive baseline. The diffraction grating configured to act as an optical splitter is further configured to be continuous within at least a central 3 mm aperture, wherein the distance vision is provided by the -1st order diffraction, and the near vision is provided by the 2nd order diffraction.

To provide an imaging device having a zoom lens that can provide high optical performance even at the time of a short-distance imaging.SOLUTION: A zoom lens sequentially includes: a first lens group (G1) having positive refractive power; a second lens group (G2) having negative refractive power: a third lens group (G3) having positive refractive power; a fourth lens group (G4) having negative refractive power; and a back group in the direction from an object to an image. At least one of lens groups having negative refractive power arranged closer to an imaging surface than an aperture diaphragm has a negative lens Ln and satisfies a predetermined condition in the zoom lens.SELECTED DRAWING: Figure 2

The disclosure provides a design method of a coupling-out grating of an AR optical waveguide, the AR optical waveguide including a coupling-in grating, an optical waveguide body and the coupling-out grating, and the design method including: S101: calculating a diffraction coupling-in angle, at which a light beam is diffracted and coupled into the optical waveguide body through the coupling-in grating, according to an angle at which the light beam is incident to the coupling-in grating, a wavelength of the light beam and a grating period of the coupling-in grating; S102: calculating a distance between two adjacent coupling-out positions of the light beam on the coupling-out grating according to the diffraction coupling-in angle and a thickness of the optical waveguide body; S103: calculating a brightness difference rate of the light beam after being coupled out multiple times through the coupling-out grating according to the maximum diffraction efficiency of the coupling-out grating; and S104: calculating the number of partitions of the coupling-out grating according to a length of the coupling-out grating, a sensitivity of a human eye to the light beam, the brightness difference rate, and the distance between the two adjacent coupling-out positions.