277 results about "Oblique incidence" patented technology

A position detection apparatus includes an illumination optical system for illuminating a first diffraction grating having periods in each of a first direction and a second direction different from the first direction, and a second diffraction grating having a period different from the period in the second direction of the first diffraction grating in the second direction, at an oblique incidence, and a detection optical system for detecting diffracted light from the first diffraction grating and the second diffraction grating, wherein a relative position of the first diffraction grating and the second diffraction grating is detected based on the detected diffracted light, and wherein the illumination optical system includes a plurality of light intensity distributions in the first direction except for on an optical axis of the detection optical system, in a pupil plane thereof.

An oblique sputtering deposition apparatus is provided for preparing a thin film. A collimator having angled passages for filtering out particles from stray directions is placed between the substrate and the incident particle flux. The angle of the passages can be adjusted from about 0 to about 90° with respect to the substrate normal according to requirements. The oblique incidence of particle flux brings forms a column structure which is also angled.

The invention discloses an electric tunable grating coupler. The electric tunable grating coupler comprises an SOI (Silicon On Insulator) substrate, an oblique incidence grating coupler, a P+ mixing area, an N+ mixing area, a pair of electrodes, a mode converter, a single mode ridge waveguide and a substrate gold reflecting mirror, wherein the SOI substrate comprises a silicon substrate, an oxideburying layer and a top silicon layer positioned at the upper position of the SOI substrate; the oblique incidence grating coupler is positioned on the top silicon layer positioned on the SOI substrate; the P+ mixing area is positioned in a panel area at one side of the oblique incidence grating coupler; the N+ mixing area is positioned in the panel area at the other side of the oblique incidencegrating coupler; the electrodes are positioned at the upper positions of the P+ mixing area and the N+ mixing area, are respectively connected with the P+ mixing area and the N+ mixing area through metal contact through holes and are used for loading electric signals; one end of the mode converter is provided with a wide waveguide, the mode converter is positioned at one end of the oblique incidence grating coupler, and the end of the mode converter, which is provided with the wide waveguide, is coupled with one end of the oblique incidence grating coupler; the single mode ridge waveguide andthe oblique incidence grating coupler are respectively positioned at two ends of the mode converter; and the substrate gold reflecting mirror is embedded in the silicon substrate positioned at the bottom part of the SOI substrate and is positioned below the oblique incidence grating coupler and the oxide burying layer.

The invention discloses an ultrathin and flexible composite wideband microwave absorption structure. The ultrathin and flexible composite wideband microwave absorption structure comprises an impedance matching structure, a frequency selection surface structure, a medium bearing structure, an energy loss structure and a metal backboard which are sequentially stacked from top to bottom, wherein the frequency selection surface structure is in direct contact with the medium bearing structure, the impedance matching structure is bonded with the frequency selection surface structure by an adhesive film, the medium bearing structure is bonded with the energy loss structure by an adhesive film, the energy loss structure is bonded with the metal backboard by an adhesive film, the impedance matching structure and the energy loss structure are respectively made of magnetic medium materials with different electromagnetic properties, and the frequency selection surface structure comprises a plurality of metal patch units arranged periodically. The microwave absorption structure provided by the invention is simple in preparation process, is flexible in texture, ultrathin in thickness and wide in microwave absorption frequency band, and has excellent polarization stability and oblique incidence angle stability.

The invention discloses a method for welding line ultrasound array full focusing imaging based on oblique incidence longitudinal waves. A present array imaging postprocessing method is only applied to processing of full matrix data collected under the situation that a phased array probe acoustic beam vertically enters a to-be-tested piece. According to the method, a wedge block is added to a phased array probe, a main acoustic beam of longitudinal waves enters a welding line of the to-be-tested piece through the wedge block; by processing the full matrix data excited and received by a phased array sensor and calculating a refraction intersection point of the acoustic beam on an interface through the wedge block based on a Snell principle, the acoustic beam propagation time of each array element reaching all imaging points is calculated, amplitudes of focus points are obtained through calculation, and then the amplitude of each focus point is focused; and finally full focusing imaging of the oblique incidence longitudinal waves is achieved. The longitudinal wave main acoustic beam in a specific direction can be generated, the defect detection effect in a welding line area and the defect recognition rate are improved; and a probe protecting effect is achieved.

The invention aims at providing an automatic detection method of an oblique incidence body wave technical steel plate, which carries out comprehensive and fast detection to steel plates with the thickness of less than 75mm and accurately detects various defects, and a device thereof, and the device consists of an electromagnetic ultrasonic detection unit and a circuit system. The invention adopts the oblique incidence body wave mode to carry out detection to the steel plates, which not only is more sensitive to the detect in size, but also can detect the defects of cracks and the like, thus having more comprehensive detection result. The detection unit adopts a mode that transverse arrangement and longitudinal arrangement are combined, thus being more sensitive to the defects of the transverse and the longitudinal direction. The invention combines an ultrasonic transmission method and a reflection method, which not only has higher sensitivity to the defects, but also can position the defects precisely, thus having higher confidence level of the detection result. The invention has wider range for detecting the thickness of the wall of the steel plate, with the highest of 75mm, thus meeting the requirements for the steel plate with thick wall.

The invention belongs to the technical field of a microwave technology and an aircraft stealth technology, and discloses a dual-band wave absorption frequency selective surface system, a design methodand an aircraft. The dual-band wave absorption frequency selective surface system is provided with a dielectric support plate, resistant thin film square rings and a circular-groove frequency selective surface, wherein the resistant thin film square rings are periodically arranged on an upper surface of the dielectric support plate, the circular-groove frequency selective surface is arranged on alower surface of the dielectric support plate and comprises a dielectric plate and a metal layer, the metal layer is arranged on an upper surface of the dielectric plate, the thickness of the metal layer is not considered, and circular grooves are periodically formed in the metal layer. By the dual-band wave absorption frequency selective surface system, k-band wave transparent/dual-band wave absorption can be achieved, an array pattern is compact, and good stability is achieved under an oblique incidence condition; the dual-band wave absorption frequency selective surface system is simple instructure; compared with a multi-layer structure, the dual-band wave absorption frequency selective surface system is only provided with the upper-layer resistant film, the intermediate-layer dielectric support plate and the lower-layer frequency selective surface, and is lighter and is lower in profile; and a transition band between the wave transparent band and the wave absorption band is small, and the wave absorption effect is good.

The invention disclose a comprehensive simulation test site for a lunar topographic environment, which comprises a closed black spatial lunar topographic test field, an illumination simulation system, a background environment simulation system and a lunar regolith and topographic simulation system, wherein the illumination simulation system in the lunar topographic test field comprises a high-power illuminating lamp which is arranged on the peripheral wall body and simulates oblique incidence of sunlight, and a plurality of low-power illuminating lamps which are arranged on the peripheral wall body of the test field or distributed on the top of the test field; the background simulation system comprises a curtain which selects sprayed lunar craters and deep space background; and the lunar regolith and topographic simulation system is constructed by utilizing simulated lunar regolith according to known lunar topographic data after simplifying complex lunar topography into typical topography of slopes, pits and stones. The comprehensive simulation test site for the lunar topographic environment can ideally simulate the lunar topographic environment through systematic and reasonable configuration of lunar regolith and topographic environment simulation, photoenvironment simulation and background environment simulation, and provides possibility for a lunar patrol detector to perform various ground tests in the lunar topographic environment.

A line image acquisition apparatus suitable for being added onto a line-scan wafer macro-inspection system which incorporates oblique incidence illumination and detection, both for brightfield and for darkfield, which incorporates double darkfield observation capability, which incorporates broadly tunable angle of incidence illumination and tunable angle of detection, which incorporates multi-channel detection into a line-scan macro-inspection system, and which is an add-on feature compatible with current line-scan macro-inspection systems.

The invention concretely relates to an ultrasonic Lamb wave-based butt weld nondestructive testing method and belongs to the ultrasonic guided-wave nondestructive testing field. An excitation source is loaded at the end of a weld joint. Two piezoelectric patches are pasted on the upper surface and the lower surface of a plate symmetrically and excited. The generated weld joint guided-wave mode propagating along the weld joint has high energy and slow attenuation, and the long-distance testing problem can be solved. The testing system is shown in the figure, and composed of a function generator (1), a power amplifier (2), piezoelectric patches (3), an oblique incidence-type piezoelectric ultrasonic sensor (4), an oscilloscope (5) and a computer (6). By utilizing the testing system, when the ultrasonic Lamb wave encounters flaws of the weld joint, flaw echoes are generated. According to the time difference between the excitation waveforms and the waveforms of flaw echoes and the group velocity of the weld joint guided-wave mode, the distance from the flaws to the excitation source can be obtained, and therefore the effective locating of weld joint flaws can be achieved.

The invention provides a high-energy laser semi-integrating-sphere array attenuator, which comprises a front panel arranged along a laser incident direction, a back panel and a plurality of attenuation units, wherein the attenuation units comprise wide-angle sampling taper holes arranged on the front panel, semi-sphere cavities arranged on the back panel, and laser emergent holes which are arranged on the edges of the semi-sphere cavities and are vertical to the back panel; the positions of the wide-angle sampling taper holes are corresponding to the positions of the semi-sphere cavities one to one; and the wide-angle sampling taper holes and the laser emergent holes are respectively arranged on the two sides of the semi-integrating-sphere cavities. In the attenuator provided by the invention, laser is coupled into the semi-sphere cavities via the wide-angle sampling taper holes, is absorbed and diffuse-reflected by the semi-sphere cavities, and then is ejected from the laser emergentholes, large amplitude attenuation of laser power density is realized, and the requirement of attenuation sampling during oblique incidence of the laser can be satisfied.

The invention relates to a magnetic-type ultrasonic oblique incidence sensor transmitter-receiver device. According to the device, an ultrasonic oblique incidence structure in which an ultrasonic transducer and organic glass is coupled can be achieved without dismounting the ultrasonic transducer. Magnetic force provided by a magnetic base of the device is several times that of a normal magnetic base, thereby ensuring that the contact between the device and a part to be tested is close, the coupling is excellent, and the operation is easy and convenient. The device comprises a certain quantity of fixing plates and is reasonable in structural design, and thus the rigidity of the device can be fully ensured. When being applied to stress detection system based on an acoustic elasticity theory, the structure provided by the invention can fully ensure the measurement precision of ultrasonic time.

The invention provides a liquid crystal phased array-based laser radar system, and relates to the technical field of laser phase control. By the liquid crystal phased array-based laser radar system, the problem that incident light and emergent light are separated by a light splitter in an existing light path and the light intensity loss can be caused by introduction of the light splitter so that the application of a beam deflection system is limited are solved. The liquid crystal phased array-based laser radar system comprises a central processing unit, a laser emission system and an echo receiving system, wherein the laser emission system comprises a laser A and an emission light path, the emission light path comprises a beam expansion collimation system A, a refined deflection system, aone fourth wave plate and a rough deflection system, the refined deflection system comprises a one second wave plate, a liquid crystal spatial light modulator (LCSLM) and a DSP controller, the rough deflection system comprises a liquid crystal polarization rotator, a liquid crystal spatial light modulator (LCPG) and a polarization grating controller, and the echo receiving system comprises a fieldprogrammable gate array (FPGA), an MPPC and a receiving light path. An oblique incidence mode is employed, an included angle between light irradiating the liquid crystal spatial light modulator and emergent light is increased, the light path is simplified, the system volume is reduced, the light intensity loss caused by the light splitter is also reduced, and the application range of the liquid crystal spatial light modulator is expanded.

The invention discloses a coordinated multi-point laser module and a gas detection system. The multi-point coordinated laser module comprises a packaging housing, a main detection laser, an collimating and beam expanding system, a Fourier lens, an auxiliary laser group and a control device, can send main detection laser light in a normal incidence manner to a gas sample chamber and can send at least four auxiliary detection laser light in an oblique incidence manner to the gas sample chamber; when a to-be-detected sample is under detection, to-be-detected sample information carried by the main detection laser light emitted out of the gas sample chamber can be made up by to-be-detected sample information carried by the at least four auxiliary detection laser light emitted out of the gas sample chamber, the detection comprehensiveness for the to-be-detected sample information is guaranteed, so that the lower limit of particle size detection is expanded effectively, and the detection precision of the whole gas detection system and the reliability of detection data are improved.

The invention discloses a flatness absolute checking method based on oblique incidence. In the method, three groups of wave surface data are obtained by the cavity interference of a Fizeau interferometer and twice oblique incidence measurement; wave surfaces are fitted by using a Zernike polynomial; and the absolute surface shape distribution of the whole plane is obtained by solving a rotating invariant and a rotating dependent variable of the surface to be detected. The invention simplifies the measuring step and shortens the measuring time and can obtain the absolute surface shape distribution of the plane to be detected only by measuring three times without disassembling and assembling a reference transmitting plane and is especially suitable for the surface shape absolute check of a high-reflectivity optical plane.

The invention relates to a residual stress distribution ultrasonic array chromatography detecting and monitoring method. The method adopts ultrasonic array to obtain detection data, is suitable for measuring the average distribution of the residual stress in a detected member, and allows acoustics image reconstruction of the average distribution state and the area position of the residual stress in the detected member to be carried out. The ultrasonic array chromatography detecting method is realized on the basis of a local signal difference principle. An ultrasonic oblique incidence technology is adopted to obtain critical refraction longitudinal waves, background data under a residual stress-free condition is collected by adopting a transmission technology in the detection process, ultrasonic array data under a residual stress condition is collected through the transmission technology, and an image is reconstructed through comparing the local detection signal and the background signal under the residual stress-free condition and the residual stress condition and combining the weight coefficient of the appearance probability of the residual stress distribution in the detected member. Pixel points in the image represent the transit time difference change attribute of the sound waves passing through the residual stress area, so the distribution state and the position of the residual stress can be differentiated. Influences of the quantity and the arrangement mode of arrays on the residual stress distribution and influences of an excitation frequency on the detection depth of the residual stress are analyzed through the residual stress chromatography imaging method.

The invention provides a micro-miniature NMR (nuclear magnetic resonance) gyroscope with application of an oblique-incidence detection light path. The micro-miniature NMR gyroscope comprises a dual-window atomic gas chamber prepared with an MEMS (micro-electromechanical system) technology, a heating structure for heating the atomic gas chamber, a magnetic field coil, a detection light path assembly, a pumping light path assembly, a photoelectric detection assembly, a signal demodulation module, a temperature control module, a magnetic field drive module and a laser drive module. According to the NMR gyroscope, the thin-sheet dual-window atomic gas chamber prepared with the MEMS bonding technology is adopted, the pumping light path and the detection light path adopt a circularly polarized light vertical window pumping mode and a linearly polarized light oblique-incidence detection mode respectively, the light path structure of the gyroscope is simplified, the overall size of the gyroscope is reduced, and meanwhile, by means of Brewster angle incidence adopted by linearly polarized detection light, high transmittance and high linear polarization degree of the detection light can be realized.

The invention discloses a narrowband interference filter which comprises substrate which is made of quartz glass materials. The upper surface and the lower surface of the substrate are respectively plated with a main peak film system and a section secondary peak film system, wherein the main peak film system is a four half-wave film system and the section secondary peak film system is a section secondary peak film pack. The narrowband interference filter is good in optical performance, high in transmittance of a passing band, deep in stopping band ending, small in oblique incidence drifting, high in stability, high in reliability, in addition, the passing band approaches to a rectangle, disturbance to identification of an active marker caused by sunlight and other stray light can be eliminated effectively when the narrowband interference filter is matched with the active marker to used, and identification accuracy is high.

An ultrasound system comprises an ultrasound probe for transmitting transmit beams and receiving receive beams. A processor controls the ultrasound probe to direct the transmit beams in a first direction to acquire a first incidence frame of data and a second direction to acquire an second incidence frame of data, wherein the first and second directions are different with respect to each other. A tissue characterization module compares the normal and oblique incidence frames of data to determine at least one property parameter of a scanned medium based on amplitude differences between the receive beams.

Due to the present invention, a reflection member including two or more layers of fixed cholesteric liquid crystal phases, in which the two or more layers of fixed cholesteric liquid crystal phases exhibit central wavelengths of mutually different selective reflection, and the two or more layers of fixed cholesteric liquid crystal phases include a layer formed of a composition including a disc-like liquid crystal compound and a layer formed of a composition including a rod-like liquid crystal compound and a projected image display member and a heat shield member which include the reflection member are provided. The reflection member of the present invention has favorable selective reflection characteristics with respect to oblique incidence rays.