26 results about "Photoelasticity" patented technology

The invention discloses an offshore wind power basic equipment stress monitoring and early warning system based on deep learning. The system comprises a data acquisition module, a mapping module, a stripe image prediction module, a fusion module, a model construction module, a stress module and an early warning module. According to the invention, the obtained multi-dimensional monitoring data is converted into a first stripe image which is consistent with a photoelastic stripe image in time and space through a mapping module and a stripe image prediction module, and then after the first stripe image and the photoelastic stripe image are fused, the stress distribution condition of the offshore wind power foundation equipment is predicted by using a stress module. And identifying abnormal characteristics in the stress distribution diagram, and in combination with a safety threshold value, judging potential risks in advance and sending out early warning. According to the method, the first stripe image and the photoelastic stripe image in the same time and space are fused to complement information loss of the first stripe image and the photoelastic stripe image, the fused image enables the stress prediction model to capture more key clues related to stress distribution at the same time, and the stress distribution can be predicted more accurately.

This invention provides a method and apparatus for photoelastic stress reconstruction based on physically constrained deep learning, relating to the fields of experimental mechanics and optical mechanics. The method involves acquiring images of the interference fringe state of a transparent specimen under load to obtain multi-channel tensor input data; using a physically enhanced convolutional neural network model for feature extraction and processing, and performing differential calculations to obtain full-field stress component output data; visualizing and rendering the full-field stress component output data to obtain reconstructed visual data; comparing the full-field stress component output data with reference benchmark data, calculating error indices, and recording process time to obtain accuracy and efficiency evaluation data; and simultaneously integrating and displaying the reconstructed visual data and the accuracy and efficiency evaluation data to obtain a comprehensive evaluation and reconstruction result. This invention solves the inherent limitations of traditional phase unwrapping and stress separation techniques.

Aspects of the present disclosure describe integrated optics-based phase controllers that include a waveguide having a core with one or more cavities whereby it can exhibit enhanced photoelastic effects and / or increased stress-induced deformation in at least one zone. The waveguides according to the present disclosure are particularly useful in stress optical phase controllers that are suitable for systems such as microwave photonics, LiDAR, and the like.

A method for measuring residual stress of a silicon wafer (1), comprising: when a silicon wafer (1) undergoing measurement is in a first physical state, separately emitting polarized light beams (A) in the radial direction and the circumferential direction of said silicon wafer towards the surface of said silicon wafer, and obtaining a first optical path difference between the polarized light beam in the radial direction and the polarized light beam in the circumferential direction; when said silicon wafer (1) is in a second physical state, separately emitting polarized light beams (A) in the radial direction and the circumferential direction of said silicon wafer (1) towards the surface of said silicon wafer (1), and obtaining a second optical path difference between the polarized light beam in the radial direction and the polarized light beam in the circumferential direction; on the basis of the first optical path difference, a first proportional relationship between the first optical path difference and the photoelastic coefficient of said silicon wafer (1), the second optical path difference, and a second proportional relationship between the second optical path difference and the photoelastic coefficient, obtaining the photoelastic coefficient; and on the basis of the photoelastic coefficient and the first proportional relationship, obtaining the residual stress of said silicon wafer (1). Further provided are a system for measuring residual stress of a silicon wafer (1) and a corresponding silicon wafer (1).

An optical polymer material includes an alternating copolymer made of a monomer of a styrene derivative and a monomer of a maleimide derivative, and has a nonlinear property in which the photoelastic coefficient of the optical polymer material decreases to a predetermined value with increase in composition ratio of the styrene derivative, and rises above the predetermined value with further increase in composition ratio of the styrene derivative. A composition ratio of the styrene derivative is within a predetermined range. An absolute value of the photoelastic coefficient is equal to or smaller than a first absolute value within the predetermined range of the composition ratio, and an absolute value of the intrinsic birefringence is equal to or smaller than a second absolute value of the optical polymer material within the predetermined range of the composition ratio.

The invention belongs to the technical field of mechanics teaching aids, and particularly discloses a portable simple photoelastic mechanics instrument for teaching, which comprises a photoelastic sample, and also comprises a sample mounting bracket, the upper end of the photoelastic sample is connected with the sample mounting bracket, and the front end and the rear end of the sample mounting bracket are through; the lever loading assembly is connected with the lower end of the photoelastic sample and is used for applying a load to the photoelastic sample; the polaroid assemblies are arranged on the front side and the rear side of the sample mounting bracket; the light source assembly is arranged on the outer side of the polaroid assembly and provides a light source. The white light source is used, so that the weight and the size of the instrument can be effectively reduced, the instrument is convenient to carry, lever loading is applied, loading visualization and visualization are achieved, light and dark stripes on the photoelastic sample are alternately arranged, small elastic deformation can be visually displayed, elastic deformation display visualization is achieved, cost is low, operation is easy and convenient, and popularization is facilitated.

The invention relates to chemically strengthened glass and a manufacturing method thereof. The present invention relates to a chemically strengthened glass having a thickness t [mm], in which, in the distribution of stress values CSx [MPa] at a depth x [[mu] m] from the glass surface of the chemically strengthened glass measured by a scattered light photoelastic stressometer, the value CSx "of the second order differential of the stress values CSx satisfies the following formula: 0 < CSx" < = 0.050 within the range CSx > = 0.

An object of the present application is to provide a phase difference film capable of producing an image display device in which unevenness in mounting is suppressed, and a polarizing plate and an image display device using the phase difference film. The phase difference film of the present application is a phase difference film having a support exhibiting a reverse wavelength dispersion in an in-plane retardation, and a liquid crystal layer directly laminated on the support, wherein the support is a polymer film subjected to a stretching treatment in at least one direction in the plane, the liquid crystal layer is a positive C-plate obtained by fixing the orientation state of a liquid crystal composition containing a liquid crystal compound, and the photoelastic constant of the support is 30 x 10 ‑12 or less.

The application belongs to the technical field of ellipsometric accurate measuring device and method, and particularly relates to an ultrahigh-speed ellipsometric accurate measuring device and method based on single photoelasticity modulation self-feedback, wherein a polarizer, a quarter-wave plate and a measured sample are sequentially arranged in the light path direction of a light source, a photoelasticity modulator, a polarizer and a detector are sequentially arranged in the reflection light path of the measured sample, and the photoelasticity modulator is electrically connected with a photoelasticity modulator driving control and a multi-channel digital lock-in amplification circuit. The application carries out multi-frequency signal lock-in amplification on the photoelectric signal modulated by a single photoelasticity modulator, takes the photoelasticity modulator driving frequency as a reference, obtains the signal amplitude of one frequency multiplication, two frequency multiplications, three frequency multiplications and four frequency multiplications, combines theoretical calculation to obtain the modulation phase amplitude caused by the long-term working temperature influence and environmental influence of the two photoelasticity modulators, and further realizes the accurate measurement of the ellipsometric parameters Δ and Ψ of the measured sample.

Provided is an injection molded light-guiding member including a substrate section, an input coupler for causing light from an image display element to enter the light-guiding member, two surfaces of a wave-guiding section that are opposite to each other and that guide incident light through repeated reflection, and an output coupler for extracting light toward an eye of an observer from a light-guiding body through any function among refraction, diffraction, and reflection of guided light, wherein an absolute value of a photoelastic coefficient is 10×10−12 Pa−1 or less, and a partial reflecting mirror that transmits a portion and reflects a remaining portion of light is formed at at least one surface among a total of three surfaces consisting of the two surfaces of the wave-guiding section and a surface of the output coupler.

This invention belongs to the field of quality inspection technology. It provides a deep learning-based quality inspection system for wine bottle caps and boxes, comprising: using photoelastic polarization to detect residual stress in the wine bottle body, introducing the material stress optical constant, determining the residual stress damage coefficient, and quantifying the stress damage degree of the wine bottle body; if the stress damage degree of the wine bottle body is low, conducting simulated transportation vibration tests on the corresponding packaging boxes of the same batch of wine bottles, collecting real-time vibration data of the wine boxes, and assessing the structural failure risk of the wine boxes; if the structural failure risk of the box body is low, constructing a dynamic stress transfer model of the cap and box based on the simulated transportation vibration test results, and determining the temporal dynamic stress of the bottle body; this invention fills the gap in traditional testing methods that neglect secondary dynamic stress damage to the bottle body during transportation, providing precise data support for packaging vibration resistance optimization, transportation condition calibration, and lightweight design.

The invention belongs to the technical field of textile industry detection, and relates to a fabric production quality online detection and judgment method fused with multi-modal data, which comprises the following steps: applying periodic stress to a fabric moving along a transmission path to form a local stress response area; thermal reaction signals of a local stress response area are collected, and a phase-locked thermodynamic map is generated; extracting abnormal hot spots in the phase-locked thermodynamic map, and generating a defect candidate point coordinate set; generating a photoelastic form graph at the position indicated by the defect candidate point coordinate set; the thermal signal characteristics of the abnormal hot spots are matched with the photoelastic form graph, and a defect diagnosis report is generated; generating a real-time quality treatment instruction according to the type and severity level of the flaw in the flaw diagnosis report; according to the method, the problem that the defect classification capability is weak due to lack of judgment basis due to single information acquisition dimension and difficulty in comprehensively evaluating defect characteristics from multiple angles in a traditional scheme is solved.

Provided are: a thermoplastic resin having sufficiently high optical properties and excellent physical properties such as excellent photoelastic coefficient and saturated water absorption; and an optical lens or the like containing such a thermoplastic resin.　The problem is solved by a thermoplastic resin containing a structural unit (A) derived from a bifunctional compound represented by general formula (1). In general formula (1), W represents a phenyl group or a cyclohexyl group, and n represents 0 or 1.

A force sensor with the following features is provided: - at least one emitter (2) which emits a first polarized electromagnetic radiation (12) during operation, - a photoelastic layer (3) with a photoelastic material (3') that is birefringent under mechanical stress, wherein the photoelastic layer (3) is traversed by the first polarized electromagnetic radiation (12) during operation, so that a second polarized electromagnetic radiation (14) is generated, - at least a second polarizer (4) that polarizes the second polarized electromagnetic radiation (14) such that a third polarized electromagnetic radiation (15) is generated during operation, and - at least one detector (5) which detects the third polarized electromagnetic radiation (15) during operation. Furthermore, a method for operating a force sensor is provided.

The application relates to the technical field of industrial vision detection, in particular to a chain belt screw production process control method and system based on industrial vision. The method comprises the following steps: performing online detection, acquiring a first image and a second image, and performing spatial alignment on the first image and the second image; performing pixel-level information supplement on a highlight area in the first image according to the brightness information of the two images; identifying an optical artifact area according to the difference between the two in a plastic chain belt area, and marking the optical artifact area as a non-detection area through first processing; then performing defect feature analysis on a screw body area in the processed image except the non-detection area, extracting defect features, comparing the defect features with preset standards, and outputting a control signal according to a comparison result. The method solves the problems that in the prior art, when a chain belt screw is detected online, the high light reflection on the surface of a metal screw hides defect details, and the photoelastic effect of a translucent plastic chain belt produces optical artifacts to interfere with defect identification.

The invention discloses a weak pressure measurement method based on a photoelastic effect and image recognition. The method comprises the following steps: S1, acquiring an initial image of a photoelastic sensing layer in a non-pressure state; s2, acquiring a measurement image of the photoelastic sensing layer in a pressure applying state of the to-be-measured object; s3, cutting the initial image and the measurement image, and reserving a stripe change area; s4, extracting grey-scale maps of RGB channels of the initial image and the measurement image, and performing subtraction to obtain a difference image; and S5, inputting the difference image into the pressure prediction model, and calculating to obtain a pressure estimation value or a pressure interval corresponding to the to-be-measured object. Compared with the prior art, the method has the advantages that a convolutional neural network (CNN) image recognition technology is creatively combined with a photoelastic mechanical effect, an end-to-end mapping model from optical interference image features to pressure information is established, and low-cost and rapid pressure (weight) interval measurement is realized.

The application belongs to the technical field of full-range ellipsometry devices, and particularly relates to a full-range ellipsometry device based on double photoelasticity cascade difference frequency modulation, which comprises a detection light source, a polarizer, a first photoelasticity modulator, a sample, a second photoelasticity modulator, a detection polarizer and a photodetector, the light path direction of the detection light source is sequentially provided with the polarizer, the first photoelasticity modulator and the sample, and the reflected light path of the sample is sequentially provided with the second photoelasticity modulator, the detection polarizer and the photodetector. The application utilizes the advantages of high modulation frequency, large modulation purity, wide light spectrum range and large field of view angle of the photoelasticity modulator, selects two photoelasticity modulators with inconsistent modulation frequencies for joint use, constructs double photoelasticity cascade difference frequency modulation, and based on the modulation technology, can realize the measurement of all four Stokes vectors of the outgoing light, and further can realize the full-range measurement of ellipsometric parameters.

The present application relates to a kind of achromatic RGB photoelasticity measurement methods based on color polarized camera, which is based on plane polarized light path implementation, in plane polarized light path, first light source and second light source of vertical distribution are sequentially through polarizer, half mirror, the tested piece and the color polarized camera of polarization array assembly respectively, birefringence effect is generated by stress at the tested piece, and photoelastic image with polarization information is collected by color polarized camera;Photoelastic image is generated by RGB channel synthesis algorithm to generate an achromatic photoelastic dark-field image;Based on photoelastic dark-field image, in combination with the calibration curve of RGB color value-equal difference line fringe number, equal difference line phase is solved;Based on the collected photoelastic image, equal inclination line phase is calculated using four-step phase shift method.Compared with the existing instantaneous photoelasticity method of circular polarized light path, the present application improves the precision and efficiency of color photoelasticity measurement and other advantages.

This utility model discloses a weak pressure measuring device, including a measuring bracket, a photoelastic sensing layer, a black placement box, a light source, a camera, and a computer. The photoelastic sensing layer is composed of two photoelastic material films orthogonally stacked and fixed to the measuring bracket. The black placement box is placed on the photoelastic sensing layer. The light source is positioned directly below the photoelastic sensing layer and is used to emit light onto it. The camera is positioned directly above the photoelastic sensing layer and is used to capture images of the deformation of the photoelastic sensing layer. The camera is connected to the computer via a data cable. By stacking the two photoelastic material films orthogonally along their optical axes to form the sensing layer, the birefringence effect is enhanced, producing clear, high-contrast interference fringes and color changes under weak pressure, greatly improving the measurement sensitivity and visualization effect.

This invention discloses a photoelastic stress measurement system and method based on a polarization grating. The stress measurement system, along the optical path, includes a light source, a polarizer, a photoelastic sample to be measured, and a polarization grating. The light emitted from the light source is converted into linearly polarized light by the polarizer. The transmitted portion passes through the photoelastic sample, where the light vector is split into two components along the two principal stress directions. The polarization grating ensures that the diffraction distribution of the incident linearly polarized light is only at the ±1st and 0th orders. Since the photoelastic model has birefringence, the linearly polarized beam exiting the photoelastic model is diffracted to the ±1st and 0th orders under the action of the polarization grating. The vast majority of the beam is circularly polarized at the ±1st order, while a very small portion, with the same polarization state as the incident beam, is distributed at the 0th order. This invention solves the problems of traditional photoelastic stress measurement methods, such as complex equipment, inaccurate measurement results, and the inseparability of phase delay and the angle of the principal stress directions in the photoelastic model.

This invention relates to the field of optical thin film inspection technology, specifically disclosing a method and system for inspecting skylight display thin films. The method includes: applying a frequency-converting electric field under controllable humidity partial voltage modulation, simultaneously acquiring picosecond photoelastic imaging data to construct a dielectric relaxation-photoelastic coupling field, identifying interface debonding precursors and encoding them as a subcritical defect entropy state matrix; using the spatial coordinates of this matrix as the focusing point to excite a multi-physics field phase-locked coherent superposition signal, reconstructing a three-band energy dissipation topology network, identifying topological defect nodes and registering them with the entropy state matrix to generate a failure prediction map; fusing the coupling field and the topology network to establish a service limit extrapolation model based on the self-organized criticality of dissipative structures, generating a personalized adaptive compensation strategy, and encapsulating it into a quality adaptive digital twin that can be embedded in the thin film. This invention achieves a leap from post-event verification to pre-event prediction, providing a new paradigm for the reliability assessment of intelligent display dimming films.

The application discloses a boundary-weighted photoelastic model internal stress separation method and a system thereof, and the method comprises the following steps: collecting model isoclinal line parameters and isochromatic line parameters; calculating a full-field principal stress, and specifying a calculation path direction and a solution region; performing boundary identification and data preprocessing; calculating a full-field shear stress, performing average pooling on the full-field shear stress; judging whether abnormal values and pixelated random errors are effectively eliminated, and whether gradient information in original data is reserved in the preprocessed data; performing boundary initial normal stress calculation; determining internal normal stress in one direction; calculating internal normal stress in another direction; respectively smoothing the internal normal stress in the two directions to obtain final full-field normal stress distribution. The application fully considers abnormal values and pixelated random errors in collected data, and the method proposed by setting a reasonable threshold and a correction method can effectively avoid the influence of collection errors on full-field stress solution.

The invention discloses a boundary weighted photoelastic model internal stress separation method and system. The method comprises the following steps: collecting isoclinal line parameters and isochromatic line parameters of a model; calculating the full-field principal stress, and appointing a calculation path direction and a solving region; boundary identification and data preprocessing are carried out; calculating full-field shear stress, and averagely pooling the full-field shear stress; judging whether the abnormal value and the pixelation random error are effectively eliminated or not, and whether the preprocessed data reserve gradient information in the original data or not; performing boundary initial normal stress calculation; internal normal stress in one direction is determined; internal normal stress in the other direction is calculated; and smoothing the internal normal stresses in the two directions to obtain final full-field normal stress distribution. According to the method, the abnormal value and the pixelation random error in the collected data are fully considered, and the influence of the collection error on the whole-field stress solution can be effectively avoided by setting the reasonable threshold value and the method provided by the correction method.

A diffractive optical element may include a slab of transparent photoelastic material and a set of acoustic transducers spread over the perimeter of the slab. The acoustic transducers generate surface and / or volume acoustic waves that induce a diffractive pattern in the slab due to photoelasticity. The diffractive patterns a dynamic, i.e. they may be changed by changing phases and frequencies of oscillation of the acoustic transducers. Focusing and redirection patterns may be used to refocus and / or redirect image light in a near-eye display.

Systems and methods for visualization of nerves are disclosed. A tissue region is illuminated with short-wave infrared (SWIR) light and reflected light is captured to form images in which nerve substructures, including bands of Fontana, are resolved. In some embodiments, nerve contrast is enhanced by dynamic polarization modulation, achieved by rotating polarizing elements or by electronically altering illumination polarization using liquid-crystal or photoelastic devices. A polarization-resolving camera may detect polarization-dependent reflectance, enabling extraction of periodic modulation unique to birefringent nerve tissue. The disclosed techniques improve nerve visibility relative to conventional imaging and may be used for surgical navigation, robotic surgery safety, or other in vivo applications.

The invention provides an injection molded light guide member and a head mounted display having the same. Provided is an injection-molded light guide member capable of providing a high-resolution image without image distortion, while suppressing undesirable situations such as uneven brightness, uneven color, and rainbow patterns, even when a partial mirror having a reflectance characteristic with polarization selectivity is disposed in an input coupler, a waveguide unit, and an output coupler. This injection-molded light guide member is provided with: a base material part; an input coupler that enters light from the image display device into the light guide member; light guide parts on two opposite surfaces for guiding the incident light by a plurality of repeated reflections; and an output coupler that extracts light from the light guide body while causing the guided light to face an eye of an observer by means of refraction, diffraction, and reflection functions, the absolute value of the photoelastic coefficient being 10 * 10-12 Pa-1 or less, and a partially reflecting mirror that transmits a portion of the light and reflects the remaining light being formed on at least one of the three surfaces of the waveguide section and the output coupler.