73 results about "Phase shift interferometry" patented technology

Apparatus and method for detecting the presence or amount or rate of binding of an analyte in a sample solution is disclosed. The apparatus includes an optical assembly having first and second reflecting surfaces separated by a distance “d” greater than 50 nm, where the first surface is formed by a layer of analyte-binding molecules, and a light source for directing a beam of light onto said first and second reflecting surface. A detector in the apparatus operates to detect a change in the thickness of the first reflecting layer resulting from binding of analyte to the analyte-binding molecules, when the assembly is placed in the solution of analyte, by detecting a shift in phase of light waves reflected from the first and second surfaces.

The present invention integrates the surface plasmon resonance and common-path phase-shift interferometry techniques to develop a microscope for measuring the two-dimensional spatial phase variation caused by biomolecular interactions on a sensing chip without the need for additional labeling. The common-path phase-shift interferometry technique has the advantage of long-term stability, even when subjected to external disturbances. Hence, the developed microscope meets the requirements of the real-time kinetic studies involved in biomolecular interaction analysis. The surface plasmon resonance microscope of the present invention using common-path phase-shift interferometry demonstrates a detection limit of 2×10−7 refractive index change, a long-term phase stability of 2.5×10−4π rms over four hours, and a spatial phase resolution of 10−3 π with a lateral resolution of 100 μm.

The invention relates to an on-line detection method for detecting the wave aberration of a projection objective of a photoetching machine. The on-line detection, revising, and controlling are done to the wave aberration of the projection objective by integrating an interferometer device on the photoetching machine. The interferometer device is a point-diffraction interferometer or a slit-diffraction interferometer and is provided with two measuring modules: a PSI measuring module and an FTM measuring module. The PSI measuring module adopts phase shifting interferometry with high measuring precision and is mainly used to detect the error calibration in an interferometer device system; the FIM measuring module adopts fourier transform method to treat with interference fringes with high measuring speed, and is mainly used to on-line detect and control the wave aberration of the projection objective. The method improves the measuring precision without reducing the measuring speed, and improves the measuring precision and reproducibility of the interferometer device by adopting a higher quality spherical reference wave to calibrate the systematic error caused by each component of the interferometer device without reducing the contrast ratio of the interference fringes.

The invention discloses an optical freeform surface interference detection system. A point light source array is adopted to generate a multi-field-of-view sloped wavefront to illuminate a measured optical freeform surface, the point light sources located on the optical axis are always lit up as reference light, and according to the phase-shifting interferometry, subregion wavefront data are recovered from a multi-field-of-view interferogram; a standard spherical surface is used for calibrating the positional relation between CCD (Charge Coupled Device) pixels and the multi-field-of-view interferogram, the position of the multi-field-of-view interferogram is shifted when the optical freeform surface is measured, and wavefront slope information is obtained from the offset; and according to the slope information and multi-field-of-view subregion wavefront data, the surface form information of the measured surface is reconstructed. A controllable point light source array-lighting scheme is generated according to the characteristics of the measured surface, and the system can cover a variety of test objects (convex-concave aspheric surfaces and freeform surfaces). The invention overcomes the defects of simplicity and high cost of the conventional freeform surface detection method, the defect of great error caused by the non-common path in the conventional detection method and the defect of high displacement precision requirement of the subaperture method.

The invention relates to a coaxial Fizeau synchronous phase shifting interferometer capable of adjusting extended light illumination and belongs to the field of an optical interference measuring device. The coaxial Fizeau synchronous phase shifting interferometer comprises an extended light source assembly, a fronting Michelson type interferometer assembly and a Fizeau main interferometer. In the invention, the fronting interferometer assembly is adopted to generate two illumination light waves of orthogonal polarization state; polarization phase shifting interferometry between a measured surface and a reference surface is realized through match of spatial coherence of the fronting interferometer and the main interferometer; and an additional fringe is removed by using the characteristic of a short coherent optical length of an extended light source space. The coaxial Fizeau synchronous phase shifting interferometer has the characteristics of long measuring distance, continuous and adjustable contrast ratio, continuous and adjustable coherent optical length, easy operation, lower error requirement on a high frequency surface shape of the reference surface and the like; and the coaxial Fizeau synchronous phase shifting interferometer can be used in the fields of high precision detection of an optical element, optical element on-line detection and super-smooth surface detection and the like.

The invention discloses a dual-wavelength phase-shift interference-based method for measuring optical heterogeneity, wherein according to dispersion characteristics of a material, an interferometer which comprises two lasers with different optical wavelengths or a wavelength tunable laser is adopted, and refractive index heterogeneity of a sample to be measured under optical waves of two wavelengths is considered as the same as optical heterogeneity to be measured of the sample to be measured; a phase-shift interferogram of the sample to be measured under the optical waves of the two wavelengths before being put into the interferometer, and a phase-shift interferogram of the sample to be measured under the optical waves of the two wavelengths after being put into the interferometer are obtained by using phase-shifting interferometry;and physical light wave phase difference of the sample to be measured under the optical waves of the two wavelengths before / after being put into the interferometer is obtained by using a phase-shift interference phase recovery algorithm, and then the optical heterogeneity of the sample to be measured is obtained. According to the dual-wavelength phase-shift interference-based method for measuring the optical heterogeneity, system errors are automatically eliminated, the sample to be measured does not need to be adjusted during a process of measuring, no special requirements for surface shape, parallelism and machining accuracy of a front and a rear surfaces of the sample to be measured exist, thus the dual-wavelength phase-shift interference-based method for measuring the optical heterogeneity is a genuine absolute measuring method and has high measuring accuracy.

The invention discloses a dual-wavelength simultaneous phase-shift interferometry method based on a monochromatic CCD. By the phase shift method, the monochromatic CCD is used for simultaneously acquiring dual-wavelength mixed phase-shift interferograms, two single-wavelength wrapped phases are respectively extracted from the acquired dual-wavelength mixed phase-shift interferograms, one of the single-wavelength wrapped phases is then subtracted from the other single-wavelength wrapped phase to work out a synthetic wavelength phase, so that synthetic wavelength phase information is obtained, and the phase information under synthetic wavelength is continuous phase distribution, which reflects the true three-dimensional shape of the surface of a measured object. The dual-wavelength simultaneous phase-shift interferometry method only needs to perform phase shift for the mixed interferograms for just one time, rather than phase shift for two wavelengths respectively, and the dual-wavelength simultaneous phase-shift interferometry method can be applied to measure the three-dimensional shapes of steps, grooves and the like with suddenly changed microstructure surfaces; the measurement method is simple, the measurement range is wide, the precision is high, and measurement is real-time, efficient and rapid.

The invention relates to a two-step quadrature phase-shift interferometry-based optical image encryption device and a method, which belong to the optical image processing technical field. The two-step quadrature phase-shift interferometry-based optical image encryption device comprises an optical image encryption device and an optical image decryption device. Due to the adoption of the two-step quadrature phase-shift interferometry-based optical image encryption device, strength information of substance light waves and reference light waves are not required to record, so the calculation amount and the storage amount can be reduced, the transmission efficiency of the information is improved, the system is simplified, and the cost is reduced. Since only two holographs are required to record, the experimental operation steps can be simplified by reducing the recording times. Since the charge coupled device (CCD) recorded digital hologram has advantages of real-time recording, digital memory, digital transmission and the like, encrypted information can be transmitted to an electronic computer of the decryption device to be decrypted in an electronic way to reappear, and the optical encryption technology can be better compatible with the digital signal processing and communication system so as to be widely used. In addition, system parameter key is also increased while the security of a double random phase coding method is guaranteed, so the security of the system is further improved.

The present invention integrates the surface plasmon resonance and common-path phase-shift interferometry techniques to develop a microscope for measuring the two-dimensional spatial phase variation caused by biomolecular interactions on a sensing chip without the need for additional labeling. The common-path phase-shift interferometry technique has the advantage of long-term stability, even when subjected to external disturbances. Hence, the developed microscope meets the requirements of the real-time kinetic studies involved in biomolecular interaction analysis. The surface plasmon resonance microscope of the present invention using common-path phase-shift interferometry demonstrates a detection limit of 2×10−7 refractive index change, a long-term phase stability of 2.5×10−4π rms over four hours, and a spatial phase resolution of 10−3 π with a lateral resolution of 100 μm.

The invention relates to microstructure topography test system and method based on a white light phase shift interferometry. The system is sequentially provided with a digital CCD (Charge Coupled Device) camera, a microscopic optical system, a piezoelectric ceramic driver, an interference objective and a piezoelectric ceramic controller connected with the piezoelectric ceramic driver; and the system is also provided with a white light source supplying a light source and a PC (Personal Computer) machine, wherein the PC machine is connected with the digital CCD camera and the piezoelectric ceramic controller through an image collection card; and the input end of the interference objective corresponds to a sample to be tested arranged on a vibration isolation platform. The method comprises the following steps of: driving the interference objective to vertically scan an object to be tested through a phase shifter and recording a collected image; determining the center of gravity through a center of gravity method; solving an error of the gravity center position and a zero order fringe position through calculating phase information at the last position of a zero order stripe; and determining the position of a zero order interference fringe through comprehensively interfering the intensity information and the phase information of a signal. The invention has high measurement efficiency, widens measuring range and improves measurement resolution.

The invention discloses a device and method for measuring a gas film gap of a dynamic pressure motor on the basis of the simultaneous phase shifting interferometry and relates to a device and method for measuring the gas film gap of the dynamic pressure motor. The invention solves the problems of a short measurement working distance of a capacitive sensor and limitation to measurement accuracy of a laser triangular sensor currently. The device disclosed by the invention mainly comprises an interference system, an orthogonal grating light splitting and phase shifting device and an image acquisition system; and the device respectively uses a round light spot and a strip light spot as axial / radial measurement light spots, adopts an orthogonal Ronchi grating to implement light splitting, adopts a four-quadrant polarizer to implement phase shifting and adopts a CCD (Charge Coupled Device) to carry out image acquisition. According to the scheme adopted by the invention, a probe of the device is vertically fixed at a certain distance relative to an axial / radial measurement plane of the dynamic pressure motor to be measured; and the simultaneous phase shifting interferometry principle, the grating diffraction light splitting principle, the polarization phase shifting characteristic and the image acquisition principle are utilized to measure axial and radial displacement change values corresponding to stiffness variation of a gas film of the dynamic pressure motor. The device has high stability and common-path, large-working-distance high-resolution measurement can be implemented.

The invention discloses an optical fiber point diffraction phase shift interferometry method of the surface shape of a large relative aperture sphere, belonging to the field of optical measurement. The method comprises the following steps of: firstly, measuring the diffraction wavefront of an optical fiber, transmitting the diffraction wavefront through a beam splitter prism, converting the diffraction wavefront into a measurement wavefront capable of covering a measured large relative aperture spherical mirror through a microobjective and reflecting on the surface of the measured spherical mirror; transmitting the microobjective by a reflecting wavefront carrying the surface shape information of the measured spherical mirror, reflecting the reflecting wavefront through the beam splitter prism, then converging to the end face of a reference optical fiber to form the measurement wavefront and converging the measurement wavefront with a reference wavefront diffracted by the reference optical fiber to form an interference; then removing the measured spherical mirror and keeping other optical elements unchanged; placing a plane mirror at the part of the focal point of the microobjective; and measuring astigmations brought by the microobjective, the beam splitter prism and the roughness of the end face of the reference optical fiber by using the same method. The invention is realized through two steps, and both the two steps utilize point diffraction spherical waves approximate to ideas as the reference wavefront and can realize the high-precision measurement of the surface shape of the large relative aperture sphere.

The invention discloses a laser white light compound interference measuring device and method. Monochromatic light phase shift interference can be combined with white light scanning interference to improve the measurement performances of the system. The measurement device comprises a white LED light source, a collimating lens, a filter, an optical microscopic interference module and an image acquisition device. The measurement method comprises the steps of: performing white light scanning interferometry of a measured sample; performing monochromatic light phase shift interferometry, wherein itis only needed to put the filter at front of a beam splitter mirror, and other portions are the same as the white light scanning interference; and combining a white light scanning interferometry andthe monochromatic light phase shift interferometry to solve the phase fuzzy problem in the monochromatic light phase shift interference. Compared to the white light canning interference, a compound interferometry result is higher in precision. Besides, the system provided by the invention employs an Michelson interference structure, the transverse measurement range is far larger than the measurement range of a commerce white light interference Mirau structure, and therefore, the laser white light compound interference measuring device and method has bigger advantage for large-size part surfacedetection.

The invention discloses a digital Moire phase shift interferometry method based on a two-step carrier splicing method, and belongs to the photoelectric detection field. The digital Moire phase shift interferometry method based on a two-step carrier splicing method includes the steps: establishing a virtual interferometer, and obtaining an ideal system residual wavefront on an image plane of the virtual interferometer; acquiring two practical interferograms of a measured surface shape under different spatial carriers; solving the two interferograms by means of the digital Moire phase shift interferometry method respectively, and obtaining two surface shape errors with different error regions and different error regions through solution; extracting the correct areas of the two surface shapeerrors to perform splicing; and then finally obtaining the surface shape error without the error regions. Therefore, the digital Moire phase shift interferometry method based on a two-step carrier splicing method solves the problem that a digital Moire phase shift method makes solution errors when encountering the large residual wavefront, so as to expand the measurement range of the traditional solving the error in the large residual wavefront by, and then extend the measurement range of the traditional digital Moire phase shift method, eliminate the residual wavefront bandwidth limitation ofthe traditional digital Moire phase shift method and realize measurement of the measured surface shape of the large residual wavefront. The digital Moire phase shift interferometry method based on atwo-step carrier splicing method can maintain the advantages of the original digital Moire phase shift interferometry method.

The invention discloses a lens focal length measuring device and method based on a Fizeau interferomenter. According to the lens focal length measuring method, two parallel flat plates different in thickness are sequentially inserted into an interference cavity in the lens focal length measuring device for introducing axial displacement of an object point and a image point, and the lens focal length is measured. The lens focal length measuring method includes the steps that a glass flat plate is placed at the cat eye position, and when no parallel flat plate is placed in a test light path, the difference W1-W0 of test wavefront data W1 and reference wavefront data W0 is obtained through phase shift interferometry; the two parallel flat plates different in thickness are respectively arranged in the test light path, and the wave difference W2-W0 and the wave surface W3-W0 which are different from each other are obtained through phase shift interferometry; the wave difference W2-W1, the wave difference W3-W1 and a Gaussian imaging formula are obtained through calculation by adopting a wavefront difference algorithm, and a calculation formula of the lens focal length is derived. Damage to the surface of a lens is avoided by the adoption of the non-contact measuring method, and the lens focal length measuring device and method are suitable for measuring positive and negative lens focal lengths.

The invention relates to a device for detecting a precision wafer based on parallel optical flat splitting polarized beam and phase-shifting interferometry. The device comprises a light source, a spatial filter, a beam expander, a polarizer, a depolarizing dispersion prism, a parallel optical flat, a quarter-wave plate and an analyzer, wherein the light source, the spatial filter, the beam expander and the polarizer are arranged on a first optical axle in sequence, the analyzer, the quarter-wave plate, the depolarizing dispersion prism, the parallel optical flat and the surface of an externalobject to be measured are arranged on a second optical axle in sequence, and the first optical axle is perpendicular to the second optical axle.

The invention relates to an optical fiber point diffraction phase shifting interferometry of an optical plane surface shape, belonging to the field of optical measuring technique. The interferometry of the invention comprises the following steps: penetrating a beam splitter from a spheric wave for measuring the optical fiber diffraction, and refracting after reflecting on the surface of the plane mirror to be measured; reflecting the spheric wave front by the beam splitter, diffracting with the reference optical fiber, and converging with the spheric wave front of the beam splitter to generate interference; analyzing and processing the interference figure by using a standard method; measuring to obtain the surface shape of the measured plane mirror and the aberration introduced by the beam splitter; removing the plane mirror to be measured, moving the measuring optical fiber to the end surface of the reference optical fiber in the conjugate position relative to the beam splitter, and converging the spheric wave front diffracted from the reference optical fiber and the spheric wave front diffracted from the measuring optical fiber to generate interference again; measuring to obtain the aberration introduced by the beam splitter; and subtracting the measuring result obtained in step 2 from the measuring result obtained in step 1 to obtain the surface shape of the measured plane mirror. The interferometry of the invention has high precision of the measuring result of the plane surface shape, is an absolute measurement method of the plane surface shape, and extends the application range of the point diffraction interferometry.

The invention discloses a digital moire fringe phase extraction method combining wavelet analysis and low pass filtering and belongs to the optical measurement and image processing technology field. The method is characterized by using actual interference graph and phase-shift virtual interference graph moire synthesis to generate a phase shift moire composite graph, and using low pass filtering and combining a phase shift interferometry to extract a preliminary result of a moire fringe phase; according to a virtual interference wavefront acquired by a virtual interferometer, combining a filtering radius of a filter to determine a distribution center and a range of a low pass filtering error in the preliminary result of the moire fringe phase; after a low pass filtering error range and the center are positioned, carrying out wavelet decomposition on the preliminary result containing the low pass filtering error; and according to the positioned error center and the range, processing a wavelet coefficient so that the filtering error can be removed, according to an approximation coefficient and a processed wavelet coefficient, carrying out reconstruction and acquiring the moire fringe phase where the low pass filtering error is removed, which means that a measurement range of digital moire interference measurement is expanded.

The invention provides a mini-displacement measurement method based on generalized phase shift digital holography, and relates to the technical field of precision measurement. By use of a generalized phase shift digital holography experiment optical path and a generalized phase shift interferometry phase shift extracting algorithm, a program is compiled so an accurate algorithm of an extracted phase shift is achieved. Though realization of the algorithm, the relation between strip change and a reference light phase shift is found and an accurate phase shift value is obtained. By use of the relation expression between the phase shift value and a micro-displacement of a reflector mirror, the displacement of a micro nanoscale of movement of a target reflector mirror is calculated. According to the invention, the accuracy can reach the nanometer level; the generalized phase shift digital holography experiment optical path is quite easy to establish; and by use of the accurate algorithm of the phase shift extraction, quite easy extraction of the phase shift value is achieved.

The invention relates to a multi-wave-length phase-shift interferometric method based on white-light interferometric color fringe processing. The method comprises: a white-light interferometric testing system is initialized and a silicon wafer is selected as a measured object; a position of the measured object on a light path in a visual range is adjusted, the measured object is scanned vertically in a scanning range, an image is stored; Bayer inverse transformation is carried out on the image by using MATLAB software to obtain true color image information; central wavelengths of R, G, B channels of the color image are calculated and obtained; the position of the measured object on the light path is adjusted again and thus the measured object is located at a focus point, seven white-light interferometric color images at different phase positions are collected and stored, and phase information is solved accurately by using a seven-step phase shift method; and preliminary estimation of the object height is obtained by using an equivalent wavelength method and height information of the object is solved precisely by using a fringe level method, so that three-dimensional morphology information of the surface of the object is obtained. According to the invention, multi-wave-length phase-shift interferometry is realized by one-time measurement, so that the external environment influence on the measuring process is reduced and the measuring precision is improved.

The invention discloses a digital watermark embedding and detecting method based on phase-shifting interferometry and singular value decomposition. The method includes two processes of watermark embedding and watermark detection, the embedding process includes watermarking information encryption is achieved by double random phase encoding and the phase-shifting interferometry of a Fresnel domain, and after encryption, a watermark image is embedded into a singular value transform domain of a host image; and an extraction method includes extracting encrypted information from a watermark image contained singular value matrix to be detected, and deciphering through double random phase decoding and the phase-shifting interferometry of the Fresnel domain to obtain a gray-scale watermark image. Compared with prior digital watermarking methods, the digital watermark embedding and detecting method based on the phase-shifting interferometry and the singular value decomposition has the advantages that the invisibility and robustness are remarkably improved, the shear-resistant capability is greatly improved, a series of image processing modes can be resisted, and high robustness and excellent safety are achieved.

A system and method for analyzing the dynamics of fluid layers on contact lenses utilizes phase shifting interferometry to quickly and accurately model the time-evolution of the fluid layers. The system and method are utilized for in vitro studies.

A method and apparatus to linearize the phase shifts produced by the wavelength-varying driving mechanism of an interferometer used in phase shift interferometry for the measurement of multiple reflective surfaces first calibrates a sequence of physical values used as the input to the driving mechanism to produce a known linear or a known constant phase shift increment between any two adjacent interferograms. The calibration process, in essence, involves the determination of the sequence of physical values, such as the voltage change with respect to the time, through the process of iteration. This sequence then is used as an input to the phase shift driving mechanism for ongoing operation of the system, thereby compensating for non-linear characteristics of the system.

Apparatus and method for detecting the presence or amount or rate of binding of an analyte in a sample solution is disclosed. The apparatus includes an optical assembly having first and second reflecting surfaces separated by a distance 'd' greater than 50 nm, where the first surface is formed by a layer of analyte-binding molecules, and a light source for directing a beam of light onto said first and second reflecting surface. A detector in the apparatus operates to detect a change in the thickness of the first reflecting layer resulting from binding of analyte to the analyte-binding molecules, when the assembly is placed in the solution of analyte, by detecting a shift in phase of light waves reflected from the first and second surfaces.

The objective of the invention is to solve the technical problems of low precision and low resolution of an existing dynamic optical wavefront phase measurement device. The invention provides a dynamic high-resolution optical wavefront phase measuring device and a measuring method, and the device and the method can achieve the active optical testing of the surface shape of an optical element and the wave aberration of an optical system through a laser, a collimating mirror, a plane mirror, a spectroscope, an absorber, a mixed modulation grating, a detector, a computer, different F # standard lenses, and a calibration mirror. The resolution is determined by the size of a detector pixel, high-resolution optical wavefront phase measurement can be achieved, and the resolution can be smaller than 0.01 mm. According to the method, a system background error is used as system data after being calibrated once, and the measured surface topography information can be calculated only by collectingan image once during actual surface shape measurement, so that compared with the traditional phase shift interference method, the method is not influenced by environments.

The invention discloses a method for detecting material uniformity of a spherical lens and belongs to the technical field of optical interferometry. The method includes that phase-shifting interferometry technology, refractive index matching liquid and a pasting plate are combined to realize detection on material uniformity of the spherical lens; by matching the refractive index matching liquid with refractive index of a detected lens, the detected lens can be detected by utilizing plane waves of an interferometer; influence, on detection results, of uniformity of the refractive index matching liquid is eliminated by stirring the refractive index matching liquid and repeatedly measuring interference detection results in a full-cavity state; material uniformity of the detected lens can be acquired by subtracting full-cavity and empty-cavity interference detection results. The method has the advantages that material uniformity of flat glass can be measured, and material uniformity of the spherical lens can be measured.

The invention provides a digital watermarking embedding and detecting method based on a three-step phase shift interferometry. The method includes a watermarking embedding process and a watermarking detecting and extracting process. The method utilizes a propagation law of a numeric field simulation optical process, so that processes that the watermarking is embedded in a digital image to be protected and the watermarking is detected from an image embedded with the watermarking are achieved, and an encryption and a decryption for information are achieved through a double random phase code and a phase shift interferometry of a Fresnel field. The digital watermarking embedding and detecting method based on the three-step phase shift interferometry has the advantages that a phase shift algorithm is introduced to a digital holography, the disadvantages and the shortages of a coaxial digital holography and an off-axis digital holography are overcome by the phase shift interferometry, and a novel information hiding encryption / decryption method is formed; the decryption can be directly performed without original plain code images in the watermarking detecting process, and the method belongs to a blind watermark algorithm; compared with traditional data encryption processes, the method is highly free and safe; and the method is high in measurement accuracy, easy to operate, rapid in processing speed, high in portability, capable of achieving the overall measurement, and the like.

The invention discloses an interferogram phase iterative recovery method based on Schmidt orthogonalization, and relates to the technical field of interferogram processing. The method comprises the steps: obtaining the intensity distribution of a set of interferograms by using the phase shift interferometry, and eliminating the interferogram background by the subtracting of the intensity distribution to obtain a differential interferogram without a background; recombining and normalizing the differential interferogram without the background to obtain an iterative relation between a variable for obtaining a precise phase of the interferogram and the phase; performing the iteration of the variable to obtain a final accurate phase value according to the above iterative relation, and completing the phase recovery of the interferogram. The method breaks through the limitation of a traditional orthogonal method, can achieve the precise phase recovery of the interferogram with less than one stripe, and is insensitive to the phase shift amount by recombining the interferogram, and can complete the accurate phase recovery even if there is only a very small phase shift amount between the interferograms.