143 results about "White light interferometry" patented technology

White light interferometry is used to obtain the height information of the topmost surface of an object having a transparent thin film on it. N frames of data are acquired from an interferometer while a white light fringe pattern is scanning through a field of view. The modulation fringe envelope R(n) is calculated for every pixel; and the topmost surface position at every pixel is determined as an offset of R(n).

The invention relates to a comprehensive diagnostic apparatus for xerophthalmia. The comprehensive diagnostic apparatus comprises an upper computer, a controller, a Placido disc, a near-infrared light illuminating system, a white light illuminating system, and an imaging system, wherein the white light illuminating system comprises a diffuse reflection plate and a white light LED array, the imaging system comprises an industrial camera, an automatic focusing lens, an optical filter wheel disc, a motor and a gear, the diagnostic apparatus respectively measures the tear meniscus height, the area of a tiny blood vessel of a conjunctiva, the structural and morphological parameters of meibomian glands, the breakup time of a tear film, and the thickness of a lipid layer of the tear film according to the principles of visible light / near-infrared light imaging measurement, structured light imaging measurement and white light interferometry, so as to provide objective diagnostic evidences and preliminary diagnostic result for the diagnosis of the xerophthalmia. The diagnostic apparatus can replace a series of separated diagnosis items during the clinical diagnosis of the xerophthalmia, the diagnosis flow of the xerophthalmia is simplified, the diagnosis time is shortened, and the objectivity and the repeatability of the diagnosis result are improved.

Bat wings are removed at step discontinuities within the coherence length of the light source of a vertical-scanning interferometer. A first height profile is obtained from a correlogram using a coherence-sensing technique. A second height profile is obtained from phase measurements at the best-focus frame position of the scanner. The two profiles are compared, and phase ambiguities are removed in conventional manner. In addition, during unwrapping the differences in height between two adjacent pixels obtained both by coherence sensing and by phase measurements are compared to flambd / 4. Where the inter-pixel height difference calculated by coherence sensing is smaller and the inter-pixel height difference calculated by phase is larger than flambd / 4, the phase measurement is corrected by 2pi increments until both coherence and phase inter-pixel height differences are within flambd / 4. This additional step removes bat-wing effects from profiles obtained by phase measurement.

A rare-earth halide material comprising a first surface region having a first surface roughness (Rrms1) and a second surface region having a second surface roughness (Rrms2), wherein the first surface roughness value is at least about 10% less than the second surface roughness value, wherein surface roughness is measured using scanning white light interferometry over an area of 1 mm2.

The invention discloses a white light interference optical profile meter, comprising a macro / micro two-stage driving and displacement metering device in a vertical direction, white light interference displacement sensors and a universal table, wherein, the white light interference displacement sensors are fixed on the driving and displacement metering device fixed on an upright post, and the upright post is fixed on a vibration isolating table facet on which the universal table is placed. The wide-range three-dimensional optical profile meter based on white light interference and vertical scanning technology realizes rough and fine two-stage driving respectively by a servo motor and piezoelectric ceramic, so as to drive the white light interference displacement sensors to integrally move, adding the servo motor in vertical displacement can enlarge the measurement range, and vertical scanning is accomplished by the piezoelectric ceramic. The measurement of macro / micro displacement is completed by using the same diffraction grating metering system. The profile meter is capable of automatically searching for interference fringes and realizing the three-dimensional profiles of wide-range non-contact measurement planes and curved surfaces, and has the characteristics of high measurement precision, large measurement range, low cost and the like.

A geometric measurement system is adapted to precisely measure one or more surfaces of objects such as corneas, molds, contact lenses in molds, contact lenses, or other objects in a fixture. The geometric measurement system can employ one or more of three possible methods of measurement: Shack-Hartmann wavefront sensing with wavefront stitching; phase diversity sensing; and white light interferometry.

The invention, belonging to the field of precision measurement, relates to a white light microscopic interferometry system and method capable of acquiring spectral information. The system comprises awide spectrum light source, a first beam splitter, a first microscope objective, a second beam splitter, a second microscope objective, a first CCD detector and a spectrum detecting module. Light emitted by the light source is split into reflected light and transmitted light by the beam splitters; the split light passes through a reference optical path and a test optical path; after the interfering on the beam splitters, the processed light is received by the CCD detector to obtain a surface microstructure of a to-be-tested plane; and the beam splitters are added into the test optical path, areflection optical signal containing the spectral information of the to-be-tested plane is introduced into the spectrum detection module to obtain an interference pattern, and Fourier transform calculation is carried out by a PC terminal to obtain spectral information. The employed ideal is novel; and the surface topography detection technology is combined with the Fourier transform spectroscopy principle, so that the surface stereoscopic shape and spectral information of the sample can be obtained simultaneously. Therefore, the multi-element measurement of the object is realized; and the experimental steps and time are saved.

An optical fiber Fourier measurement with switching white light interferometer implements Fourier transforms on white light spectrum output from transducer interferometer, the carrier frequency is Fourier spectrum defined by interferometer optical path difference, two sets of carrier frequency components are separated and symmetrical in the frequency space; one set of components is filtered for anti-Fourier transforms and plural logarithm operation, phase information of the transducer interferometer is set as an imaginary part of signals and separated from the background formed by lighting source spectrum outline and interference fringes contrast; the phase information of the transducer interferometer is limited within (minus Pi, Pi) according to operation procedure, the 2 Pi phases polarize of phase information is phase unwrapped, the measuring range is not limited with the 2 Pi phase; absolute optical path difference of transducer interferometer is calculated from phase information, thus realizing testing. The method of the invention prominently increases accuracy of white light spectrum peak measuring method and Fourier peak value frequency switching method.

The invention provides a micro-nano structure and morphology measurement device and method based on digital scanning and white light interference. The method includes the steps of projecting white light processed through beam expanding and collimation to the surface of an object to the measured and the surface of a reference mirror inside an interference microscope through semi-transparent and semi-reflective mirrors by means of a device composed of a digital micro mirror array, an imaging unit, the semi-transparent and semi-reflective mirrors, a white light source, an interference microscope objective, the object to be measured, a working table, a control unit, a spectrograph, optical fibers and an optical fiber coupling unit, enabling the white light to interfere with reflected light, obtaining the interference light intensities through the semi-transparent and semi-reflective mirrors, obtaining the surface of the digital micro mirror array through the imaging unit, controlling the micro mirror defection angles corresponding to pixels of the digital micro mirror array one by one so that the light intensities corresponding to different pixels can enter the optical fiber coupling unit one by one, transmitting spectral information obtained by a spectrograph and corresponding to the interference light intensities to the control unit, and conducting phase analysis on distribution of the spectrums corresponding to the interference light intensities to obtain the relative height of the surface of the object to be measured. The micro-nano structure and morphology measurement device and method have the advantages that the structure is simplified, the measurement accuracy is high, and the anti-interference capacity is high.

A system and method for active visual measurement and servo control using laterally sampled white light interferometry (L-SWLI) for real-time visual tracking of six-degree-of-freedom (6 DOF) rigid body motion with near-nanometer precision. The visual tracking system is integrated with a 6 DOF motion stage to realize an ultra precision six-axis visual servo control system. Use of L-SWLI obtains the complete pose of the target object from a single image frame to enable real-time tracking. Six-degree-of-freedom motions are obtained by measuring the fringe pattern on multiple surfaces of the object or from a single surface with additional information gained from conventional image processing techniques.

The invention relates to an optical fiber white light interferometry method, in particular to a phase-shift white light interferometry method based on a 3*3 optical fiber coupler, belonging to the technical field of optical fiber sensing. A 2*2 optical fiber coupler and a 3*3 optical fiber coupler form an optical fiber M-Z interferometer, and a wavelength scanning light is injected into the optical fiber M-Z interferometer. Magnitudes of three paths of output white light interference spectrum signals are equal, and an angle of 120 degrees is formed between every two paths of output white light interference spectrum signals on the phase. When the wavelength scanning light scans from Lambda 1 to Lambda 2, three paths of output signals I1, I2 and I3 are obtained, and Delta is demodulated through computing or constructing two paths of orthorhombic signals and utilizing a derivation cross multiplying method. The Delta is subjected to the unwrapping operation to demodulate linear phase information after computed. The absolute optical path difference of the interferometer can be computed by using the linear phase information. The invention can absolutely measure the optical path difference of the optical fiber interferometer with high precision and high speed.

Bat wings are removed at step discontinuities within the coherence length of the light source of a vertical-scanning interferometer. A first height profile is obtained from a correlogram using a coherence-sensing technique. A second height profile is obtained from phase measurements at the best-focus frame position of the scanner. The two profiles are compared, and phase ambiguities are removed in conventional manner. In addition, during unwrapping the differences in height between two adjacent pixels obtained both by coherence sensing and by phase measurements are compared to flambd / 4. Where the inter-pixel height difference calculated by coherence sensing is smaller and the inter-pixel height difference calculated by phase is larger than flambd / 4, the phase measurement is corrected by 2pi increments until both coherence and phase inter-pixel height differences are within flambd / 4. This additional step removes bat-wing effects from profiles obtained by phase measurement.

The invention relates to the technical field of fibre optical sensing, in particular to a wave length SWLI measurement technology based on a 3*3 coupler. Wave length scanning narrowband light is divided into two routes by the coupler, one route of light is input into an interferometer based on the 3*3 coupler, the other route thereof is input into an etalon and a fiber grating which are connected in series. When wave length scanning is carried out, three output white light interference spectrums of the interferometer and a transmission spectrum of the etalon and the fiber grating are probed. Start-stop wave length of wave length scanning is confirmed by the transmission spectrum of the etalon and the fiber grating, three white light interference spectrum signals have difference of 120 degrees between each two signals in phase position, a passive phase demodulation algorithm based on the 3*3 coupler can directly demodulate output phase change of the interferometer caused by wave length scanning, so as to work out absolute optical path difference. The invention has high measuring precision and can realize high-speed measurement.

The invention discloses a white light interference three-dimensional reconstruction method applicable to surface topography detection, which mainly comprises intensity information and phase information, wherein the intensity information is obtained by quickly generating an envelope curve corresponding to an interference curve through a Guassian function, function fitting is performed on the envelope curve, and the position of a peak value of a continuous function is the zero optical path difference position; and the phase information is calculated based on a Carre algorithm. The results are combined to obtain height information, and the three-dimensional topography is reconstructed. The white light interference three-dimensional reconstruction method is applicable to surface topography measurement for various samples. The solved zero optical path difference position is the maximum value of the continuous function, more accurate than the maximum value of discrete sampling points and notsubject to sampling frequency fluctuations of a phase shifter. The white light interference three-dimensional reconstruction method reduces requirements for the test environment, still can obtain anaccurate test result under external interference such as vibration, central wavelength fluctuations of a light source, camera noise and low surface reflection coefficient of a tested sample, and is greatly improved in robustness.

The time delay (and therefore the OPD) between object and reference beams in an interferometer is manipulated by changing the spectral properties of the source. The spectral distribution is tuned to produce a modulation peak at a value of OPD equal to the optical distance between the object and reference arms of a Fizeau interferometer, thereby enabling the use of its common-axis configuration to carry out white-light measurements free of coherence noise. Unwanted interferences from other reflections in the optical path are also removed by illuminating the object with appropriate spectral characteristics. OPD scanning is implemented without mechanical means by altering the source spectrum over time so as to shift the peak location by a predetermined scanning step between acquisition frames. The invention and its advantages are applicable to optical coherence tomography as well as conventional white light interferometry.

The invention provides a micro-topography measurement method based on a white light interference zero optical path difference position picking algorithm. The micro-topography measurement method basedon the white light interference zero optical path difference position picking algorithm comprises the following steps: S1, obtaining a white light interference template curve; S2, vertically scanningan object to be measured, collecting interference fringes, and obtaining sampling points; S3, using a gravity center method or an extremum method to quickly and coarsely locate the zero optical path difference point; S4, determining a search range, taking a number of sampling points within a certain range around the zero optical path difference point as points to be matched; S5, matching the points to be matched with the template curve in the search range to obtain a finely positioned zero optical path difference point; and S6, obtaining the accurate relative height of the object surface topography according to a correlation between the zero optical path difference and the morphology height, thereby reconstructing the 3D shape of the object to be measured. The micro-topography measurementmethod based on the white light interference zero optical path difference position picking algorithm has simple algorithm, high speed, high precision and good anti-noise ability.

A geometric measurement system is adapted to precisely measure one or more surfaces of objects such as corneas, molds, contact lenses in molds, contact lenses, or other objects in a fixture. The geometric measurement system can employ one or more of three possible methods of measurement: Shack-Hartmann wavefront sensing with wavefront stitching; phase diversity sensing; and white light interferometry.

A probe for measuring oxygen, temperature, and pressure in a space to be monitored, comprising: a housing, comprising a thermally conductive material; an oxygen sensor disposed within the housing, comprising: a first end having coated thereon a coating which fluoresces at a fluorescent frequency when exposed to light having an excitation frequency in the absence of associated oxygen, and which undergoes a dampening of said fluorescence in the presence of associated oxygen; and a second end operatively connected to an optical fiber that extends through the housing; wherein the first end extends through the housing and is adapted to be exposed to the space to be monitored; a temperature sensor disposed within the housing adjacent to the thermally conductive material, comprising a fiber Bragg grating, or a semiconductor material, such as a GaAS material, wherein the temperature sensor does not extend through the housing and is not exposed to the space to be monitored; a pressure sensor disposed within the housing, comprising a fiber Bragg grating or a Fabry-Pérot white light interferometry sensor having a first end which extends through the housing and is adapted to be exposed to the space to be monitored.

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 white light interferometer with a fast zero-setting system. A light path of the white light interferometer is added with the following system, which is characterized in that: lasers emitted by a tunable laser are expanded by an expander and then merged to the light path through a third beam splitter and a first beam splitter which are installed behind a collimating system; a dichronic mirror totally reflecting long wave is arranged between a converging lens and a camera, one end of a detector receives reflective lights of the dichronic mirror and the other end thereof is connected with a computer via an AD / DA card. According to the invention, zero path difference setting of the white light interferometer can be realized by wavelength scanning laser interference measurement, and an angle of dip of a surface to be measured is obtained by analyzing the spacing of white light interference fringes in order to achieve automatic setting. Since the above procedures are free from operations with large data, the setting time of the white interference interferometer can be reduced to about 20 seconds, which dramatically improves the detection efficiency of the white interference interferometer. The white interference interferometer with the fast zero-setting system is especially suitable for those large-area surfaces or circumferential surfaces which require the measurement of various positions and need to be spliced.

A method of manufacturing an optical element involves an interferometric test of the optical element using an interferometer system of a Fizeau type combined with principles of white-light interferometry. The optical element is disposed in a cavity between a Fizeau surface and a mirror, and an optical path difference between a back surface of the optical element and the mirror is determined for determining parameters of the optical element, such as a thickness thereof. Measuring light from an optical delay apparatus can be supplied to the Fizeau interferometer through an optical fiber.

The invention discloses a surface morphology measuring device capable of continuous zooming. The device comprises a light source, a collecting lens system, a light splitting prism, an interference object lens, a zooming optical system, an imaging optical system, an area array CCD camera, a micro movement device and an objective table, emergent type of the light collecting system is orientated to the light splitting prism, reflection light of the light splitting prism is orientated to the interference object lens, the zooming optical system is arranged coaxially between the light splitting lens and the imaging optical system, and an interference optical path is integrated and connected with an illumination optical path of the light splitting prism. The zooming optical system is a continuous zooming optical system, and comprises a compensation set, a zooming set and a fixed set. Aimed at requirements of different amplification multiplying power, it is only required to adjust the amplification multiplying power M of the zooming optical system instead of replacing the object lens to zooming in / out the view field of measurement, and the amplification multiple can be adjusted continuously. The device is suitable for realizing the surface morphology measurement in the phase difference interferometry or the vertical white light interferometry.

A simultaneous phase-shifting white light scanning interferometer comprises a white light scanning interferometer, a simultaneous phase-shifting module, and a scanner. Light from a short coherence length light source may be polarized and then split, by a polarization type beam-splitter, into orthogonally polarized reference and test beams. The simultaneous phase-shifting module comprises a plurality of detectors, allows for controlled phase shifts between the reference and test beams, and creates at least three independent interferograms, each with different phase shifts between the reference and test beams. The scanner translates the simultaneous phase-shifting module with respect to an object under measurement.

The present invention is a test system and test method based on white light interferometry, characterized in that the test system includes a microscopic optical system, a digital CCD camera, an image acquisition card, an interference system, piezoelectric ceramics, piezoelectric ceramics Controller, air floating platform, white light halogen light source and PC. The test method of the present invention controls the piezoelectric ceramics to drive the sample to be tested to scan vertically through the PC to operate the piezoelectric ceramic controller, so that the interference fringes are swept across the measured area, and the image collected is recorded by a digital CCD camera; After the image is filtered, the white light interference signal of a single pixel is extracted, the background light intensity value of the white light interference fringes obtained is subtracted, the light intensity of each pixel is converted from the time domain to the frequency domain, and decomposed in the frequency domain to obtain the wave number and The phase relationship; the position of zero optical path difference is obtained by integrating the wavenumber and phase information in the frequency domain of the interference signal, and the extraction of surface height information is realized.

The invention discloses a method and device for detecting uniformity of optical glass based on white light interferometry. The device comprises a white light interferometer and two double-frequency laser feedback displacement measurement systems, and the two double-frequency laser feedback displacement measurement systems and the white light interferometer are in a linkage structure and are combined into an integral structure for performing mobile scanning. The detection method comprises the following steps: calibrating the white light interferometer, and obtaining a proportionality coefficient between the optical path difference and fringe offset; acquiring the introduced optical path difference variation of the optical glass to be detected, and measuring the thickness deviation of the to-be-detected optical glass at the same detected position by using the displacement measurement systems; determining the refractive index deviation of the optical glass to be detected according to the optical path difference obtained by the white light interferometer and the thickness deviation obtained by the displacement measurement systems; scanning the whole optical glass to be detected, and finishing detection of the uniformity of the optical glass to be detected. The method and device for detecting the uniformity of the optical glass are high in precision and low in cost, and the testing process is simple and convenient.

The invention relates to a method and an apparatus for measuring the thickness of a transparent film by broad band interferometry, comprising the steps of preparing a correlogram of the film by an interferometer, applying a Fourier transformation to said correlogram to obtain a Fourier phase function, removing a linear component thereof, applying a second integral transformation to the remaining non-linear component to obtain an integral amplitude function of said non-linear component, identifying the peak location of said integral amplitude function and determining the thickness of the film as the double value of the abscissa at said peak location considering a refractive index of a film which is dependent on wavelength. The last two steps may be replaced by identifying the peak locations of said integral amplitude function and determining the thickness of the films as the double values of the abscissas at the peak locations.

The invention relates to a non-contact micro-nano three-dimensional measurement method, which measures the three-dimensional distribution of a sample in the white light interferometry mode; in the scanning probe precision measurement mode, uses scanning probe technology to combine white light interference and non-contact scanning probe The measurement technology is organically combined to finally realize the precise measurement of three-dimensional shape; non-contact micro-nano three-dimensional measurement device, including white light interference system, probe sensing system, Z-axis precision scanning system, probe positioning system, XY-axis precision scanning systems, control and data processing systems. The invention organically combines white light interference and non-contact scanning probe measurement technology, and can realize high-speed and high-precision three-dimensional shape measurement.

The invention discloses a white light interference and laser scanning-based morphology measurement device comprising a three dimensional motion platform and a white light-laser measurement system positioned on the same. The measurement system comprises a white light source 1, three light splitting prisms, a microscopic ocular lens 5, a microscopic object lens 6, an interference object lens 7, a four-quadrant photoelectric sensor 8, a laser device 9 and an image sensor 10; two measurement optical paths and a laser measurement optical path are provided; the laser optical path has the following structure: light sent via the laser device 9 is turned via a third light splitting prism 4, and then the light is focused onto a surface 11 being measured via the microscopic object lens 6; the light passes through the microscopic object lens 6, the third light splitting prism 4, and a second light splitting prism 3 after being reflected by the surface 11 being measured; then the light is projected to the four-quadrant photoelectric sensor 8 and is used for measuring height information of the surface 11 being measured; light, reflected back by the surface 11 being measured, sent via the laser device 9 is turned via the second light splitting prism 3; after passing through a first light splitting prism 2 and the microscopic ocular lens 5, the light and illumination backlight formed via the white light source 1 are imaged onto the image sensor 10, and a collection image for laser measurement is formed.

The invention provides a polarization fading restraining device and method for a white light interferometry sensor array. The polarization fading restraining device is composed of a wide-spectrum light source, an optoisolator, an optical fiber coupler, an optical path delay line, an optical fiber sensor array, an optical detector and a signal collecting, processing and displaying unit and further comprises a polarization state continuous rotation mechanism. When optical path matching occurs between the optical path delay line and a certain optical fiber sensor, and the polarization state changes continuously and rapidly within the range from 0 degree to 360 degrees, the amplitude of white light interferometry signal intensity of the sensor goes through the whole changing process from maximum to minimum; the sum of the intensity of any two interference peak values with the polarization state difference of 180 degrees is taken as an output signal of the sensor, polarization fading caused by elements such as the optical fiber sensor, the delay line and transmission optical fibers can be restrained, and the polarization fading restraining device has the advantages that a polarization element is not introduced, the control process is easy and convenient to carry out, and the incidence polarization state does not need to be considered. The polarization fading restraining device and method can be used in the fields of real-time monitoring and measuring of multi-point strain or temperature, and monitoring of a large-size intelligent structure and the like.