11 results about "Oblique incidence" patented technology

The application discloses a kind of based on acoustic wave detection and wave field separation building structure safety detection method and device, it is related to acoustic wave detection and safety detection technical field.The method includes obtaining initial acoustic wave detection data and carrying out acoustic wave travel time analysis, the spatial distribution range of preliminary determination internal abnormal area;For the range, increase observation density and obtain local enhanced detection data;Wave field separation is carried out to data in space domain and time domain, filter out surface wave and oblique incidence interference wave, extract vertical reflection wave data;Based on vertical reflection wave data, three-dimensional acoustic imaging is carried out, and the spatial positioning feature and geometric profile of abnormal area are obtained;Safety evaluation model is combined to carry out safety evaluation to target detection area.The present application can effectively peel off complex interference wave field, improve abnormal body spatial positioning precision and safety evaluation reliability.

This application relates to the field of tunnel construction safety monitoring technology, and discloses an intelligent identification method for water seepage risk at the tunnel face in water-rich clay layers. This method controls an active infrared excitation module to project radiation in an oblique incidence manner, uses polarization imaging to acquire sequences and calculates Stokes vectors; calculates the degree of linear polarization based on the Stokes vectors and performs threshold segmentation to generate a water film distribution mask; uses the Stokes vectors to construct a polarization angle field reflecting local normal changes as texture features, solves the optical flow constraint equation to obtain the instantaneous velocity field; performs frequency domain transformation on the velocity field, extracts the proportion of low-frequency creep energy through power spectral density analysis, and determines the soil rheological softening factor; finally, combines the water film distribution, rheological softening factor, and instantaneous velocity field to construct a mudslide risk index. This invention utilizes polarization texture reconstruction to solve the problem of weak texture tracking and eliminates elastic vibration interference through frequency domain energy decoupling, effectively improving the accuracy of mudslide risk identification.

This invention provides a method for measuring dielectric constant based on oblique incidence light reflection difference technology. The probe light emitted by the laser 1 is converted into p-polarized light by the polarizer 2, and then modulated into p-polarized light and s-polarized light by the photoelastic modulator 3. The p-polarized light and s-polarized light are emitted alternately at a frequency of 50 kHz, and after passing through the phase shifter 4, a fixed phase difference is generated. Then, the light is focused by the first lens 5 and obliquely incident on the surface of the sample 6 to be tested, with the incident range between 50° and 60°. The signal light reflected from the surface of the sample 6 to be tested is incident on the analyzer 9 after passing through the second lens 8. The analyzer 9 is used to zero the fundamental frequency signal of the system. The signal light after passing through the analyzer 9 is absorbed by the photodetector 10 and converted into an electrical signal. The electrical signal is demodulated by the first lock-in amplifier 11 and the second lock-in amplifier 12 into a DC signal, a fundamental frequency signal I (Ω), and a harmonic signal I (2Ω). The demodulated signal is acquired and processed by the data acquisition and processing unit 13.

The present application relates to a kind of optical detection systems with full-angle oblique incidence dark field illumination system, belong to wafer defect detection technical field, especially to full-angle oblique incidence dark field illumination system optical detection system.The optical detection system provided by the present application, by the combination of first cone lens and second cone lens, collimate incident laser beam as parallel annular light beam, then realize full-angle oblique incidence dark field illumination by annular reflector and annular focusing system, fundamentally overcome the problems of existing single light source directional sensitivity and high precision of installation and adjustment of divergent annular light beam, poor expansibility, while ensuring the advantages of dark field high contrast, high precision and non-destructive testing, significantly improve system detection sensitivity, installation and adjustment convenience and function expansion capability.

This invention belongs to the field of two-dimensional lateral offset measurement technology, and provides a method for synchronous measurement of two-dimensional displacement of metasurfaces based on quasi-continuous domain bound states. The method includes: acquiring a metasurface lattice sample containing dual markers; determining the band structure of the quasi-continuous domain bound states and its corresponding resonant electric field distribution through electromagnetic field simulation; determining the correlation between the normalized coupling amplitude component and the overall bias vector direction through electromagnetic field simulation; establishing a multi-solution correspondence between the incident light polarization direction and the overall bias direction; determining a unique overall bias direction from the multi-solution correspondence based on the chiral spectral differences and full width at half maximum (FWHM) response exhibited by the dual markers under oblique incidence of circularly polarized light; and calculating the two-dimensional overlay error by combining the determined overall bias direction with the preset artificial bias information. Compared with traditional methods, this application achieves synchronous measurement of two-dimensional displacement in characterizing overlay errors in photolithography processes.

The application provides a kind of wideband wide-angle wave absorber based on three-dimensional frequency selective surface, comprising a plurality of three-dimensional frequency selective surface units with same structure and continuous arrangement, each three-dimensional frequency selective surface unit is a hollow cuboid, and each three-dimensional frequency selective surface unit comprises horizontal structure, vertical structure and metal bottom plate arranged in sequence from top to bottom; the wave absorber provided by the application can significantly improve the angle stability of the wave absorber by combining the horizontal structure with the vertical structure, and for 0-60° oblique incidence of TE and TM waves, more than 90% absorption can be achieved within 2.1 times the frequency bandwidth; meanwhile, the wave absorber in the application has the advantages of low profile, small thickness and period size, is easy to integrate with other devices, and is high in convenience; in addition, a center-symmetric pattern design is used in each layer structure of the frequency selective surface unit in the application, which reduces the polarization direction sensitivity of the wave absorber to incident electromagnetic waves.

Embodiments of the present application provide an illumination shaping device for oblique incidence light beam, an optical equipment and a detection method. The illumination shaping device comprises a first aspheric mirror and a second aspheric mirror. A first generatrix of the first aspheric mirror is along a first direction. A second generatrix of the second aspheric mirror is along a second direction perpendicular to the first direction. The first aspheric mirror is used to form a first flat-top light spot distributed along a third direction on a detection surface. The second aspheric mirror is used to form a second flat-top light spot distributed along a fourth direction perpendicular to the third direction on the detection surface. Wherein, an initial light beam forms a shaped light beam after being modulated by the first aspheric mirror and the second aspheric mirror. When the shaped light beam is obliquely incident on the detection surface, flat-top light spots distributed along different directions are formed on the detection surface. In the oblique incidence state, the uniformity difference before and after the focal point is small, and a flat-top line light spot with good uniformity is formed, thereby providing good illumination performance for the detection surface.

The present application relates to the technical field of intelligent sensing detection and optical scattering method surface defect intelligent identification, and discloses a yoga mat surface defect automatic identification method based on intelligent sensor.In the surface of the measured object, a two-dimensional coordinate and a discrete sampling array are established, and a unified installation posture is installed.Under the condition of fixed oblique incidence, the scattering intensity of each point is scanned according to a multi-angle sequence, and the integrity and range are verified.According to the fixed angle weight, an angle spectrum weight matrix is formed.The residual error is obtained by point-by-point difference with the defect-free reference matrix, and the mutation intensity is synthesized by row-by-row difference to construct a matrix.According to the threshold value generated by the reference mutation statistics, the candidate abnormality is generated.On the grid, the connected domain is extracted by four-neighbor connection, the area is removed if it is insufficient, and the center and area are calculated.The number, position and area of defects are outputted and visualized marked.

The application discloses a kind of laser beam detection system and method based on reflection, including two reflecting prisms, reflecting prism back is conical prism, front is plane mirror.Two reflecting prisms are placed oppositely, and the part of plane mirror that contacts light is parallel to each other, the application utilizes two reflecting prisms, and the part of plane mirror that contacts light is parallel to each other, according to the difference of laser power, the relative position of two lenses is relatively moved, to ensure that incident beam and emergent beam are not transmitted in the mode of propagation, and according to the height of power, the number of times of turning of light beam is determined, the relative distance of two reflecting prisms is adjusted, and the angle of adjusting the relative horizontal position of two lenses is adjusted, the purpose is to realize the position of incident spot and emergent spot unchanged, convenient to use, realize whether normal incidence or oblique incidence can be transmitted spot in the position of different prisms, and the energy of each beam of light of non-use of transmission is reduced.

The invention relates to a wide-angle oblique incidence-oriented near-to-eye display system and a hologram generation method, and the method comprises the steps: obtaining the initial phase distribution of a reflection-type silicon-based liquid crystal spatial light modulator plane, and enabling the initial phase distribution to have a physical resolution; a virtual oversampling grid is constructed, the initial phase distribution is mapped to an expanded high-resolution grid, and the sampling interval of the expanded high-resolution grid is smaller than the physical sampling interval; constructing a modulation light field on the expanded high-resolution grid, and superposing a linear phase term corresponding to oblique incidence; carrying out propagation calculation on the modulated light field by adopting a Shifted angular spectrum method to obtain high-resolution light field distribution of a target plane; the high-resolution light field distribution of the target plane is mapped back to the physical resolution through average downsampling, a reconstructed image is obtained, and the method has the advantages that on the premise that high quality is kept, the calculation efficiency and the generation acceleration capacity are greatly improved, and the technical effect that hologram generation is rapidly completed is achieved.

This invention relates to a method for controlling the sidewall roughness and reducing structural defects of feature areas on a substrate. The method includes adjusting the inclination angle of a particle beam for oblique incidence particle beam etching of at least one sidewall of a feature area. This technique enables improved control of sidewall roughness and reduction of structural defects in various applications such as semiconductor manufacturing. Methods for pattern improvement, cyclic surface preparation, and etching the sidewalls of feature areas are also disclosed.