606 results about "Birefringence" patented technology

The invention discloses a bone joint lesion area automatic labeling method and system based on image processing, and belongs to the field of bone joint lesion area labeling. According to the invention, a bone joint reflection signal is obtained by combining the polarization-state-adjustable laser light source with polarization-sensitive optical coherence tomography, and a three-dimensional birefringence distribution diagram is generated through matrix analysis. And after non-local mean filtering is carried out on the distribution map, a lesion edge contour is extracted based on a dynamic gradient amplitude, and a binary mask is generated. Mask pixels are converted into network nodes containing space coordinates, gradient directions and birefringence, and a topological network is constructed based on the Euclidean distance of adjacent pixels. The weight is calculated through the node intersection density and the birefringence, and a graph attention network is utilized to aggregate multi-layer features to extract lesion topological features. The features are mapped to a three-dimensional space to construct a lesion probability distribution field, an interactive labeling result is generated through contour surface extraction and transparency mixed rendering, and the accuracy of labeling the complex lesion area of the bone joint can be improved.

The invention relates to an error compensation method of a birefringence self-calibration laser level meter, in particular to the field of laser level meters, and aims to improve the precision of the laser level meter by combining a birefringence effect, physical modeling and neural network optimization. Firstly, temperature data are collected in real time, Kalman filtering is used for noise reduction, and accurate data are provided for physical modeling; then, through physical constraints such as a heat conduction equation and a Jones matrix, a coupling relation between the temperature gradient and optical parameter changes is established; then, dynamically optimizing the refractive index correction by using a physical information neural network to avoid an overfitting problem; and finally, calculating optical path difference compensation by using a hardware accelerator, correcting a system error in real time, and feeding back and adjusting a network weight. According to the method, the precision and the stability of the laser level meter in an environment with relatively large temperature change are effectively improved.

The gallium nitride-based semiconductor laser comprises a substrate, a lower limiting layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper limiting layer which are sequentially arranged from bottom to top. According to the semiconductor laser element, the multi-vacancy electron phonon regulation and control layers of a multi-layer structure are arranged in the semiconductor laser element, and the electron affinity distribution characteristic and the polarization optical phonon energy distribution characteristic of each multi-vacancy electron phonon regulation and control layer are limited, so that single-vacancy, vacancy group and multi-vacancy regulation and control electron phonon structures are formed; the electron phonons are localized between the lower limiting layer and the lower waveguide layer, stokes frequency shift formed by photon energy difference between pump light and oscillation light is reduced, phonon vibration and phonon transport heat loss are reduced, the heat dissipation performance of a laser element is improved, thermal mismatch between epitaxial layers is improved, the thermal lens effect and stress birefringence effect of the laser are inhibited, and the laser efficiency is improved. The problems of laser beam distortion and depolarization are improved, and the laser beam quality factor is improved.

Disclosed is an apparatus and a method for depth sensing that includes a scanning light source configured to sequentially illuminate an environment utilizing a scan pattern. The apparatus also includes a birefringent layer adapted to receive and split reflected scan pattern from the environment into an ordinary ray (O-ray) image and an extraordinary ray (E-ray) image. The apparatus further includes an imaging sensor positioned along an optical path of the birefringent layer to capture the O-ray image and the E-ray image as transmitted therefrom. The apparatus further includes a processor configured to compute differences between positions of the O-ray image and the E-ray image and derive a depth map of the environment based on the computed differences.

The invention discloses a large-aperture plate glass stress birefringence surface imaging measurement method, belongs to the technical field of optical measurement, and aims to solve the technical problem of low glass stress birefringence measurement efficiency in the prior art. Comprising the following steps: moving a sample to be measured and a 1 / 4 wave plate out of a measuring light path, rotating a polarizer to find an extinction position, and rotating the polarizer by N angles nearby to obtain an angle # imgabs0 #; keeping the polarizer and the analyzer unchanged, moving the 1 / 4 wave plate into a measurement light path, rotating the 1 / 4 wave plate, and finding an extinction position; rotating the polarizer by N angles near the extinction position to obtain an angle # imgabs 1 #; the positions and the directions of the 1 / 4 wave plate and the polarization analyzer are kept unchanged, and the sample to be measured is moved into a measuring light path between the polarizer and the 1 / 4 wave plate; the polarizer is rotated through the polarization rotating mechanism, when the included angles between the polarizer and the x axis of the reference coordinate system are 0 degree, 60 degrees and 120 degrees respectively, the light intensities of the three images are obtained through the CCD camera, and the stress birefringence of the sample to be measured is obtained according to the three light intensities.

An imaging optical system according to the present disclosure includes: an aperture stop; an image-forming optical system that causes an image to be formed toward an imaging plane of an image sensor; and an optical phase modulator that includes a substance having a birefringence index, and gives two pupil functions to the image-forming optical system. The following conditional expressions are satisfied:1≤(2×L×tan(w)+D) / D<1.4  (1)λ / 4*0.75<Re<λ / 4*1.1  (2), whereL: a distance between the aperture stop and the optical phase modulator; D: an aperture diameter (diameter) of the aperture stop; w: a maximum angle of incidence of a principal light ray that enters the aperture stop; λ: a wavelength of light; and Re: phase retardation caused by birefringence of the optical phase modulator.

The invention discloses a light spot adjustable optical system, a diffraction optical module and laser processing equipment, and relates to the technical field of precision processing. The optical system comprises a laser, a beam expander, a diffractive optical module and a focusing module which are sequentially arranged in the light path direction, the diffractive optical module comprises at least one diffractive optical element, and the diffractive optical element is manufactured based on a geometric phase liquid crystal polymer birefringent material. The diffractive optical module is used for regulating and controlling light spot characteristic parameters corresponding to a Gaussian beam, the Gaussian beam is emitted by the laser and enters the diffractive optical module after being expanded and collimated by the beam expander, and the light spot characteristic parameters comprise a light spot distribution position and light spot energy intensity. By the adoption of the optical system, laser energy distribution can be optimized, splashing is effectively restrained, and the welding quality and the processing efficiency are improved.

Provided are: an optical laminate which uses a biaxially stretched polyethylene terephthalate film as a base material, has bending resistance, and in which iris irregularities are suppressed; and an image display device which uses the optical laminate. This optical laminate is used in an image display device, and is provided with: a light-transmitting base material which is formed from a biaxially stretched polyethylene terephthalate film and which has in-plane birefringence; and an optical functional layer provided on one surface of the light-transmitting substrate, the arithmetic average roughness Ra of the surface of the optical functional layer being 0.04 [mu] m or more, the average inclination angle [theta] a of unevenness present on the surface of the optical functional layer being 0.30 DEG or more, and the in-plane retardation Re of the light-transmitting substrate defined by formula (1): Re = (nx-ny) * d being 2,000 nm to 7500 nm (inclusive). Here, nx is the refractive index in the slow axis direction, ny is the refractive index in the in-phase axis direction, and d is the thickness of the translucent substrate.

The embodiment of the invention provides a liquid crystal composition and application thereof. The liquid crystal composition comprises an additive and three compounds with specific structures, and the liquid crystal composition is high in birefringence, appropriate in clearing point, not prone to crystallization at low temperature, good in high-temperature-resistant stability and anti-ultraviolet stability and beneficial to application in liquid crystal devices.

Method for producing a substrate (202) for an optical element (200) of a lithography system (100), comprising the steps: a) Providing (S1) a crystal substrate (204) which has a crystal lattice (206) with at least a first, second, third and fourth crystal direction (302, 306, 308, 310) and a surface (214) which is arranged substantially perpendicular to the first crystal direction (302), wherein a geometric projection (306', 308', 310') of the second, third and fourth crystal direction (306, 308, 310) onto the surface (214) each characterizes an azimuthal installation orientation (138) of the crystal substrate (204) in an optical system (102, 104, 136) of the lithography system (100) with respect to a minimum stress-induced birefringence upon irradiation of a polarized radiation (210), and the installation orientation (138) is an orientation with respect to a rotation of the crystal substrate (204) about a central axis (220) passing through the surface (214) and arranged parallel to the first crystal direction (302), and b) determining (S2) an angular position (δ1, δ2, δ3) of at least one of the geometric projections (306', 308', 310') of the second, third and fourth crystal directions (306, 308, 310) onto the surface (214).

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 provides a calcium fluoride crystal defect detection system and method, and relates to the technical field of detection, and the method comprises the following steps: preprocessing a crystal to determine a reference position and environmental parameters, and then respectively carrying out optical uniformity detection and stress birefringence detection to obtain an interference fringe pattern and polarization state change data; and optical path difference data and stress field data are generated. And through spatial registration and data association analysis, extracting areas with both refractive index anomaly and stress anomaly as candidate defect areas, quantifying defect strength and stress influence range, and finally outputting a quality judgment result of the crystal defect. The method improves the defect detection precision and reliability, and is especially suitable for high-precision calcium fluoride crystal quality control.

The invention discloses a rheology-birefringence combined in-situ testing device and method based on chopper rotation frequency signals, belongs to the technical field of optical testing, and aims to solve the technical problems that an existing Spark-FB device is low in measurement accuracy and limits application scenes. The laser emitter emits a light beam along a set angle (forming an angle of 45 degrees with the horizontal plane), the light beam is converted into linearly polarized light through the polarizer, and an optical signal is modulated through the rotating chopper; the modulated light beam penetrates through a polymer sample to which a shear flow field is applied by a commercial rheometer, and transmission light carrying optical anisotropy information of the sample sequentially passes through a 1 / 4 wave plate and a polarization analyzer, and is finally received by a photoelectric detector and transmitted to a lock-in amplifier for analysis. According to the invention, an independent datum reference signal is provided through the chopper, decoupling and combination of a commercial rheometer and a birefringence light path are realized, and synchronous and accurate in-situ measurement of rheological and optical properties of a high polymer material under a deformation condition can be realized.

The invention relates to the technical field of material analysis, in particular to a light microscope-field emission electron microscope combined shale rock slice analysis and identification method, which comprises the following steps of: firstly, combining a brightness distribution condition represented by a bright field image of a shale rock slice and a birefringence deviation condition represented by a cross polarization image from an optical angle; determining a mineral discrimination index representing an atomic number agent; applying offsets of different sizes based on the distribution condition of mineral discrimination indexes and the surface fluctuation condition of shale rock slices, and determining a position offset vector by combining gray scale gradient distribution on the basis; and finally, determining the cross-scale positioning and more accurate electron microscope objective table coordinates corresponding to each pixel point in combination with a position offset vector in a pixel coordinate conversion process based on an image physical distance scale and rotation translation processing, so that the cross-scale positioning accuracy of the optical microscope and the field emission scanning electron microscope is higher. The reliability of analyzing and identifying the shale rock slice is obviously improved.

The invention discloses a liquid crystal compound containing 2, 4, 5-trifluorobenzene, a preparation method and a composition thereof. The structure of the compound disclosed by the invention is shown as a general formula I; and the liquid crystal composition disclosed by the invention comprises the liquid crystal compound disclosed as the general formula I. The liquid crystal compound has the advantages of low dielectric loss, good light stability, wide nematic liquid crystal phase, high birefringence, low viscosity, good low-temperature intermiscibility and the like. The composition based on the liquid crystal compound provided by the invention obtains relatively high dielectric tuning rate, extremely low dielectric loss and low rotary viscosity under high frequency; and the material has the advantages of good light stability, large birefringence, wide working temperature range and the like. The liquid crystal composition provided by the invention has the characteristics of large birefringence, low viscosity and the like, so that the liquid crystal composition is suitable for manufacturing liquid crystal optical elements and high-frequency assemblies. # imgabs0 #

An electronic device may include a display module that generates light and an optical system that redirects the light towards an eye box. The system may include an input coupler on a waveguide and a lens that directs the light towards the input coupler. The input coupler may include a prism having a reflective surface that reflects the light into the waveguide. The reflective surface may be curved to provide the light with an optical power. The prism may be configured to expand a field of view of the light. A birefringent beam displacer may expand the effective pupil size of the light. The lens may include lens elements that converge the light at a location between the lens elements and the waveguide. A switchable panel may be placed at the location and toggled between first and second orientations to increase the effective resolution of the light.

The invention discloses a birefringence lens and a system and method for realizing FINCH imaging based on the birefringence lens, the birefringence lens comprises a birefringence generation module and an optical path difference compensation module, the birefringence generation module comprises a first birefringence lens and a first lens, and generates a combined focal plane and a holographic plane; the optical path difference compensation module comprises a third birefringent lens, the optical axis of the third birefringent lens and the optical axis of the first birefringent lens are in an orthogonal relation, the focal power symbols of the third birefringent lens and the first birefringent lens are the same, and the optical path difference generated by the first birefringent lens is compensated and controlled within the coherence length of light. And the total optical path of the formed first polarized light is close to that of the second polarized light. According to the invention, one or two groups of birefringent lenses with the same focal power symbol are used for compensating the optical path difference, the curvature radiuses of the two surfaces of the lenses are controlled, so that the thicknesses of all radial positions are very close, and the error is within a smaller range for all light rays penetrating through the lens.

A system and method for performing virtual birefringence imaging and virtual staining (e.g., Congo red) of label-free human tissue is disclosed to show that a single trained neural network can rapidly transform autofluorescence images of label-free tissue into brightfield and polarized microscopy images, matching their histochemically-stained versions. Blind testing with quantitative metrics and pathologist evaluations on cardiac tissue showed that the virtually stained polarization and brightfield images highlight amyloid patterns in a consistent manner, mitigating challenges due to variations in chemical staining quality and manual imaging processes in the clinical workflow.

The invention discloses a stress compensation method for balancing thermally induced birefringence of a laser crystal, and the method comprises the steps: S1, fixing the crystal on a stress compensation device, and guiding a laser beam to pass through the geometric center of the crystal in the direction of an optical axis; the invention also discloses a stress compensation device for balancing the thermally induced birefringence of the laser crystal, the stress compensation device comprises a clamping table, the clamping table is internally provided with a first limiting surface and a second limiting surface which are intersected and arranged at a first set angle, and the first limiting surface and the second limiting surface are combined to form a positioning structure; the polarization state of the laser beam can be detected in real time through the polarization measurement unit, and force is applied to the crystal through the stress compensation device, so that the internal stress of the crystal is more balanced, and the birefringence effect is reduced.

The invention discloses an ultra-clear layered structure high-light-transmittance screen protection film and a preparation method thereof, and relates to the technical field of screen protection films, the ultra-clear layered structure high-light-transmittance screen protection film comprises an anti-scraping layer, an optical compensation layer, a substrate layer and a pressure-sensitive adhesive layer which are sequentially arranged from outside to inside; the anti-scraping layer is prepared from the following raw materials in parts by weight: 75 to 85 parts of UV acrylic resin, 10 to 20 parts of nano SiO2, 1 to 3 parts of UV initiator and 0.1 to 0.3 part of fluorosilane modified resin. According to the invention, the SiO2 and TiO2 films are alternately deposited, light reflection is reduced by using a multilayer film interference principle, the light transmittance of the protective film is remarkably improved, visual interference caused by ambient light reflection is reduced, the display definition and color rendition degree of a screen are improved, and by using the characteristics of extremely high transparency and low birefringence of COP, the light transmittance of the protective film is improved. Scattering or polarization distortion generated when light passes through is avoided, and the optical performance is further optimized in cooperation with the optical compensation layer.

The invention relates to the technical field of ray tracing, in particular to a method for tracing non-sequence polarized rays in a birefringent medium, which comprises the following steps of: firstly, determining parameters of the birefringent medium and parameters of incident light, secondly, iteratively calculating wave vectors and refractive indexes of transmission light and reflected light generated after the incident light enters the birefringent medium, then, the polarization states of the transmission light and the reflected light are calculated through singular value decomposition, the propagation direction, the Fresnel amplitude coefficient, the transmissivity and the reflectivity of the transmission light and the reflected light are further calculated, the propagation process and the optical path of the incident light are finally obtained through calculation, and ray tracing is completed. According to the method, the non-sequence polarized light can be accurately tracked in the birefringent medium, the universality is high, and the tracking result accuracy is high.

The invention relates to the technical field of photoelectrons, in particular to an ultrahigh-precision birefringence detection system and method based on a geometric phase jump effect. The system comprises a laser, a half-wave plate, a quarter-wave plate, a polarizer, a crystal to be measured, a rotating table, a first beam splitter prism, a second beam splitter prism, a reflector and a charge coupling element. A linearly polarized light beam in the horizontal direction passes through a half-wave plate and a quarter-wave plate and then is split in a first beam splitting prism, an interference light beam after beam splitting is reflected and then enters a second beam splitting prism together with a main light beam passing through a crystal to be detected for beam combination, and then the interference light beam passes through a polarization analyzer and is collected by a charge coupling element; adjusting the voltage applied to the crystal, observing the brightness change of the interference fringes, recording the voltage required by the brightness change, and calculating the refractive index change. The change of the refractive index in the crystal material is observed by utilizing the geometric phase jump effect of the crystal material, and ultrahigh-precision measurement of the change of the refractive index of the crystal is realized.

A method of a biometric recognition system of performing real-eye detection and associated biometric recognition system are disclosed. The method comprises capturing at least one image comprising a representation of an eye of the individual, which image is captured utilizing polarized light reflected at the eye and received at a polarization-sensitive camera capturing said image, wherein a polarization configuration is selected which produces an iso-chrome pattern of the representation of the eye in the captured image, detecting, from the representation, birefringent features of a cornea of the individual, aligning the detected birefringent cornea features with birefringent cornea features of an expected eye representation, determining, by matching the detected birefringent cornea features with the expected birefringent cornea features, whether the birefringent features are correctly rendered in the captured image, and if so determining that the eye is a real eye.

A system for frequency conversion of laser pump radiation includes an optical element for frequency conversion of lasers or laser beams with power scalability. The element has a nonlinear birefringent, thin plate crystal. A pump beam generates frequency-shifted radiation. Phase or quasi-phase matching conditions are in the crystal between beams. Frontside and backside of the crystal have high-reflective and partially-reflective coatings, obtaining intensity enhancement of the pump and frequency-converted radiation, and maintaining relative phase delay between beams, maximizing conversion efficiency. The crystal contacts a heat sink through the high-reflective coating, minimizing temperature inhomogeneity in the crystal. Intrinsic longitudinal heat flow provides power scalability. The element, used intra-cavity, acts as a wavelength-selective component forcing laser operation on resonance of the element, maximizing frequency conversion. The wavelength selectivity allows single-frequency operation of high-power lasers with intra-cavity frequency conversion.

The invention relates to the technical field of optical thin films, and particularly discloses a high-birefringence laminated reflecting film and a preparation method thereof. According to the laminated reflecting film, 4, 4 '-biphenyl dicarboxylate modified PET is used as a raw material of an A layer, PMMA or PETG is used as a raw material of a B layer, the difference value of the glass transition temperatures Tg of the raw material of the A layer and the raw material of the B layer is controlled to be smaller than or equal to 5 DEG C, and the laminated reflecting film formed by alternately laminating the raw material of the A layer and the raw material of the B layer is subjected to synchronous two-way stretching and heat setting treatment; according to the application, PET is modified by the BB monomer, and a biaxial stretching process and the content of the BB monomer are regulated and controlled for the first time, so that Tg difference values of the raw materials of the layer A and the raw materials of the layer B are close, meanwhile, a refractive index difference value is increased, the reflecting film with excellent optical performance and mechanical performance can be obtained with a small number of lamination layers, and the reflecting film has high in-plane birefringence, high in-plane birefringence, high in-plane birefringence, high in-plane birefringence, high in-plane birefringence and high in-plane birefringence. And the reflectivity reaches 74% or above.

The invention belongs to the field of quantum precision measurement, and particularly discloses an all-fiber phase detection system and method based on polarization interference quantum weak measurement. The device sequentially comprises a laser light source, a front selection module, a phase regulation and control module, a rear selection module and a photoelectric acquisition module along a light path. The front selection module prepares linearly polarized light emitted by the laser light source into two equal-amplitude superposition states in a cross-polarization mode as initial polarization states, and the phase regulation and control module senses the phase difference after change conversion of a physical quantity to be measured, dissipates the phase difference accumulated by the two polarization states in the sensing transmission process, and adjusts the phase difference of the two polarization states. And the post selection module performs nearly orthogonal projection measurement on the polarization state, in the process, a birefringence phase difference caused by a physical quantity to be measured is converted into a weak-value amplified light intensity signal, and the photoelectric acquisition module obtains the physical quantity to be measured by monitoring the relative variation of the optical power. Based on the quantum weak measurement principle, the birefringence phase difference caused by the to-be-measured physical quantity is converted into the weak value amplified optical power signal, and the sensing sensitivity is improved.

The invention discloses a polarization conversion metasurface and a design method and device thereof, and the metasurface comprises a substrate which is used for receiving incident light in a polarization state and forming emergent light; the first microstructure surface is arranged at the upstream of the substrate and is used for carrying out polarization state conversion on the incident light; wherein the first microstructure surface comprises a plurality of microstructures which can be periodically arranged, and the microstructures have a birefringence characteristic. The polarization conversion metasurface specifically comprises the substrate and the first microstructure surface, the metasurface can achieve polarization conversion of incident light through the birefringence characteristic of the first microstructure surface, so that the thickness of the composite polaroid is reduced, meanwhile, the manufacturing process is simpler than that of the composite polaroid, the production cost is reduced, and the production efficiency is improved. The overall structure of the optical path system is simplified.

The first purpose of the present invention is to provide a polycarbonate resin having excellent fluidity and small orientation birefringence. The second purpose of the present invention is to further provide, on the basis of the first purpose, a polycarbonate resin having a high Abbe number, a small orientation birefringence, and a small photoelastic coefficient. The third purpose of the present invention is to further provide, on the basis of the first purpose, a polycarbonate resin having a small orientation birefringence, a high refractive index, and a high glass transition temperature. The polycarbonate resin contains units represented by formula (1) and / or formula (2) and units represented by formula (3), and has a weight-average molecular weight Mw of 10,000-55000. (In formula (3), R1-R4 each independently represents a hydrogen atom or a hydrocarbon group having 1-10 carbon atoms)

This invention relates to a retardation film comprising: an A layer having a slow axis, and a B layer having a slow axis at an angle of 85° to 90° to the slow axis of the A layer; the A layer is formed of a resin A having positive intrinsic birefringence; the B layer is formed of a resin B having negative intrinsic birefringence; the resin B comprises polyester, polycarbonate, or polyester carbonate, wherein the polyester, polycarbonate, or polyester carbonate contains a fluorene framework; the overall in-plane retardation of the A layer and the overall in-plane retardation of the B layer satisfy a specific relationship; the in-plane retardations Re(450) and Re(550) of the retardation film at wavelengths of 450 nm and 550 nm satisfy a specific relationship; the overall thickness T of the A layer... A The overall thickness T of layer B B The ratio of T A / T B It ranges from 30 / 70 to 65 / 35.

This invention discloses a method for controlling photon spin-orbit coupling in an organic alloy microcavity, belonging to the field of optical microcavity technology. This invention prepares β-type Pe by doping different amounts of DCA into Pe using a volatilization method. 1‑x DCA x An organic alloy, wherein x ≤ 20 wt%, allows for the controllability of crystal color from yellow-green to orange-red. Furthermore, this organic alloy exhibits birefringence, and its application in the fabrication of optical microcavities allows for the observation of TE-TM spin-orbit coupling and Rashba-Dresselhaus spin-orbit coupling within the microcavities. This provides a novel type of microcavity for studying the interaction between light and matter in organic alloy microcavities, and the controllability of photon spin-orbit coupling within these microcavities can be achieved by adjusting the value of x.