870 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 invention relates to an optical film, a polaroid and a display device. The optical film comprises a base material layer and a depolarization function layer located on one side of the base material layer. The depolarization functional layer comprises at least one main body layer and birefringent particles dispersed in the at least one main body layer; wherein the included angle between the slow axis direction of the birefringent particles and the rolling direction of the base material layer is larger than or equal to 35 degrees and smaller than or equal to 55 degrees; when linearly polarized light enters the optical film, the linearly polarized light is converted into circular polarized light and / or elliptical polarized light by the depolarization function layer. The depolarization effect can be achieved through the method which is simpler in manufacturing process, lower in cost and higher in yield, and therefore the eye protection effect is achieved.

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.

The invention relates to a 213nm all-solid-state deep ultraviolet laser and application thereof, and belongs to the technical field of lasers. The laser comprises a laser diode, a pump light focusing system, a pump end mirror, a laser crystal, a deep ultraviolet output mirror, a sum frequency crystal, a frequency doubling crystal and a total reflection end mirror which are sequentially arranged along a light path, the pump end mirror, the deep ultraviolet output mirror and the total reflection end mirror form a V-shaped resonant cavity, and the laser crystal, the sum frequency crystal and the frequency doubling crystal are all cuboids. And birefringence main shafts of the laser crystal, the sum frequency crystal and the frequency doubling crystal are arranged in a staggered manner. Visible red light with the wavelength of 640 nm is adopted as fundamental frequency laser, only two-step frequency conversion is needed for output from the fundamental frequency laser to 213 nm, and the laser has the advantages of being simplified in process, small in size, easy to adjust, high in conversion efficiency, large in output power, low in manufacturing cost, stable in performance and the like.

A control device which controls an operation of a compensation device which compensates for birefringence and / or polarization mode dispersion, which is received by signal light having propagated through an optical transmission line, by digital signal processing using a finite impulse response filter includes: a detection signal reception unit which receives a detection signal which is a signal indicating a detection result of a detection device which optically detects polarization fluctuation in the optical transmission line; and a setting unit which decides a setting regarding an update frequency or an update interval of the number of taps of the finite impulse response filter or an update frequency or an update interval of a tap coefficient of the finite impulse response filter, based on the detection result of the detection device.

The invention discloses a method for improving optical storage capacity based on ultraviolet femtosecond laser multi-cycle low-temperature direct writing, and belongs to the technical field of laser processing. Leveling the sample table; designing a random data structure and calculating parameters; preparing a random data structure; reading and characterizing a random data structure; according to the method, firstly, ultraviolet femtosecond laser with the wavelength of 343 nm is used for replacing infrared / visible band laser used in traditional five-dimensional optical storage, secondly, a multi-cycle scanning mode is used for replacing an existing scanning mode, and birefringence modification with the smaller size is induced in quartz glass at low temperature; the tiny birefringence modification is used for realizing data writing and reading of the optical memory with higher storage density; according to the multi-cycle scanning mode, heat accumulation in the machining process is affected by changing single-point one-way acting time, so that the dot spacing is shortened, and the storage capacity is increased.

The embodiment of the invention discloses a compound, a liquid crystal composition and application thereof, relates to the technical field of liquid crystals, and is used for solving the technical problem that the service life of electronic equipment is short due to the fact that a liquid crystal material is poor in material performance and high in material performance attenuation speed. The compound has a structure as shown in a formula (I). # imgabs0 # wherein X1 and X2 are each independently selected from the group consisting of hydrogen, deuterium, tritium, at least one halogen, and at least one hydrocarbyl group, and at least one of X1 and X2 is not hydrogen. The compound has higher birefringence, better dielectric anisotropy, lower rotary viscosity, higher clearing point, better low-temperature stability and the like, and when the compound is used as a liquid crystal compound, the performance degradation speed of a liquid crystal material is slow, so that the service life of electronic equipment can be prolonged.

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.

An FMCW lidar system, the FMCW lidar system comprising: a laser light source configured to emit a swept laser light; the light engine comprises a light emitting / receiving device, the light engine is configured to receive the sweep frequency laser and emit at least one part of the sweep frequency laser as a detection light beam from the light emitting / receiving device, the detection light beam is incident to an obstacle and then generates a reflection light beam, and the light emitting / receiving device is further configured to receive the reflection light beam; the scanning assembly is arranged on one side of the light transmitter / receiver and is configured to deflect the detection light beam to realize detection light beam scanning; and the birefringence component is configured to compensate a transmitting and receiving deviation angle caused by the movement of the scanning component, so that the detection light beam and the reflection light beam are transmitted and received by the same port of the light transmitter / receiver.

The invention relates to a backlighting (13) which extends in a flat manner, emits light, and has an optical film in order to monitor and limit the viewing angle range of a viewer. When viewed in the direction of a viewer, the optical film comprises a first polarization layer (1) with a first absorption axis, which forms an angle of 0° to 30° together with a surface normal of the optical film, at least one phase-shifting compensation layer for improving the limitation of the viewing angle range, and a second polarization layer (2) with a second absorption axis, which is oriented parallel to the surface of the optical film. According to the invention, different embodiments and combinations of compensation layers which are designed to be spatially homogenous and which are made of uniaxially or biaxially birefringent materials are provided, wherein the materials and thickness of the compensation layers are specified such that the luminance is minimal in a specified solid angle range which does not comprise the entire half space, apart from a recessed cone along the viewing direction.

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.

Methods, devices and systems are described to eliminate or reduce unwanted polarization aberrations associated with interference filters. An example method for producing a polarization aberration compensator for a thin film interference filter includes obtaining a set of Mueller matrix values based on polarization measurements of the thin film interference filter over a spectral range, and generating a metric based on a difference between a compensated Mueller matrix and an identity matrix over the spectral range. The compensated matrix represents a cumulative Mueller matrix for a combination of the thin film interference filter and the polarization aberration compensator. A configuration of the polarization aberration compensator is determined based on evaluating the metric that eliminates or reduces the difference between the compensated Mueller matrix and the identity matrix over the spectral range. Configuration parameters, including thicknesses of birefringent layers, fast-axis angles and the number of birefringent layers in the compensator are obtained.

The object of the present invention is to provide a cyclic olefin polymer having a high refractive index, a low Abbe number and a low birefringence, a method for producing the same, and an optical element using the cyclic olefin polymer. The cyclic olefin polymer of the present invention comprises structural units derived from a naphthyl-containing alicyclic compound (A) represented by the following formula (1) at a predetermined ratio [wherein R 2a ~R 5a One of the groups is naphthyl, and the remaining groups and R 1a As described in the specification] or its hydrogenated product.

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 invention provides an extensional rheometer suitable for a polymer sample. The extensional rheometer comprises a base; the high-pressure cavity is mounted on the base, and the high-pressure cavity is suitable for providing different pressure environments; the two stretching rollers are arranged in the high-pressure cavity in parallel at intervals, and the two ends of the sample are connected to the two stretching rollers; the driving assembly is suitable for driving the stretching roller to rotate so as to stretch the sample; the two characterization windows are respectively arranged on two opposite side walls of the high-pressure cavity, and the characterization windows are suitable for allowing detection light beams generated by an external detection light source to penetrate through so as to obtain change information of a microstructure of the sample in a stretching process; and the torque sensor is arranged between the stretching roller and the driving assembly and is suitable for acquiring data that the stretching force generated by the sample in the stretching process changes along with different pressure environments.

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 belongs to the technical field of organic photoelectric materials, and discloses a high-transparency high-refractive-index organic polymer material as well as a preparation method and application thereof. According to the organic polymer material, an acrylic monomer with a spiro structure and a monomer with disulfydryl are subjected to free radical polymerization to obtain a polysulfide polymer with a main chain containing the spiro structure, and the polymer shows high transparency and high refractive index. According to the invention, the monomer with a spiro structure is polymerized with the disulfydryl monomer through sulfydryl-sparse click polymerization at normal temperature or photopolymerization reaction under ultraviolet light, so that the material has high refractive index and high transparency and also has low birefringence. The all-organic polymer material has wide application prospects in the fields of organic light-emitting diodes, micro-lens elements in double charge-coupled devices, high-performance complementary image sensors, all-polymer optoelectronic devices, polymer-based optical waveguides, photovoltaics, storage devices and the like.

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.

There has been a demand for an optical film having excellent glass-range photoelastic coefficient and a polarizing plate which uses this optical film. The present invention provides an optical film which is characterized by containing an ester-based resin that contains 50% by mole or more of a fumaric acid ester residue unit represented by formula (1) and having a negative birefringence, and a photoelasticity regulator having a positive birefringence, and which is also characterized in that the absolute value of the glass-range photoelastic coefficient thereof is 5×10−12 Pa−1 or less.(In the formula, each of R1 and R2 independently represents a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 3 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms.)