273results about "Reflective surface testing" patented technology

The invention relates to a method for comprehensively measuring reflectivity, which comprises the following steps: dividing continuous incident laser beams into a reference beam and a detection beam, wherein the reference beam is focused on a photoelectric detector for direct detection and the detection beam is injected into an optical resonant cavity; using a cavity ring-down technology to measure an optical element with reflectivity more than 99%, respectively measuring a ring-down time tau 0 of an original optical resonant cavity output signal and a ring-down time tau 1 of the measured optical resonant cavity output signal after an optical element to be measured is added, and calculating the reflectivity R of the optical element to be measured; using the spectrophotometry to measure the reflectivity of the optical element to be measured when the R value is less than 99%; moving away an output cavity mirror; focusing detecting light reflected by a measuring mirror on the photoelectric detector for detecting while recording a light intensity signal ratio of the detection beam to the reference beam; and calibrating to further obtain the reflectivity R of the optical element to be measured. The device for measuring reflectivity can be used for measuring optical elements with any reflectivity and also can be used for realizing the high-resolution two-dimensional imaging of the reflectivity distribution of a large-aperture optical element.

The invention relates to a system for detecting a large-aperture and high-order convex aspheric surface. The system comprises a phase shift interferometer, an auxiliary spherical reflector, a computer-generated hologram and a computer, wherein the computer is connected with the phase shift interferometer; a front focal point of an optical system comprising the computer-generated hologram and the high-order convex aspheric surface and a focal point of an optical wave sent by the phase shift interferometer coincide, and a rear focal point and a sphere center of the auxiliary spherical reflector coincide; after the optical wave sent by the phase shift interferometer passes through the computer-generated hologram, the optical wave is reflected by the high-order convex aspheric surface and becomes a standard spherical wave; after the standard spherical wave is reflected by the auxiliary spherical reflector, the standard spherical wave goes back in the same way to the phase shift interferometer, so that subaperture zero-crossing detection of the area corresponding to the high-order convex aspheric surface is realized; the phase shift interferometer obtains a subdomain, having overlapping areas, on the high-order convex aspheric surface; and a data processing unit in the computer processes data in the subdomain, and full-aperture surface-shaped distribution information of the high-order convex aspheric surface is obtained. The invention further provides a device for detecting a convex spherical mirror or a convex aspherical mirror.

The invention relates to an illumination system (12) of a microlithographic projection exposure apparatus (10), comprising a pupil surface and a substantially planar arrangement of beam deflecting elements (28) which can preferably be triggered in an individual manner and are used for variably illuminating the pupil surface. Each beam deflecting element (28) allows a projection light beam (32) that is incident thereon to be deflected in accordance with a control signal which is applied to the beam deflecting element (28). A measuring illumination device (54, 56, 58, 60; 88; 90; 98) directs a measuring light beam (36) that is independent from the projection light beams (32) onto a beam deflecting element (28). A detector device detects the measuring light beam (38) after the latter has been deflected on the beam deflecting element (28). An evaluation unit determines the deflection of the projection light beam (32) from the test signals supplied by the detector device.

A system and method for spectroscopic detection of a loss in a resonator cavity. The system comprises: a tunable laser source for generating a laser beam; a frequency locking system for either locking the frequency of the laser beam to a resonance of the resonator cavity or locking the length of the cavity to the frequency of the laser beam; a first modulation element for modulating the laser beam at a first modulation frequency to generate a modulated laser beam; an input coupler adapted for directing the modulated laser beam into the resonator cavity; a first directing element for directing a first portion of light reflected from the input coupler to a first photodetector to generate a first detected signal; and a first demodulator capable of demodulating the first modulation signal from the first detected signal to generate a first error signal which is a function of the loss in the resonator cavity.

An apparatus includes a measurement unit and a calculation unit, wherein the calculation unit expresses a measurement error of each measurement as a polynomial including a term that has a coefficient whose value is dependent on setting of the measurement area and a term that has a coefficient whose value is not dependent on the setting of the measurement area, obtains a matrix equation with respect to the coefficients of the polynomial by applying a least-squares method to each of the measurement data items for the overlapping region, assigns data about the terms of the polynomial and each of the measurement data items for the overlapping region to the matrix equation, calculates the coefficients of the polynomial from a singular value decomposition of the matrix equation to which the data has been assigned, and corrects each of the measurement data items for the measurement areas by using the coefficients.

A measurement-purpose light source generates a measurement light used for measuring an optical characteristic of an object to be measured, and the measurement light includes a component in a wavelength range for measurement of the optical characteristic of the object. An observation-purpose light source generates an observation light used for focusing on the object to be measured and checking a position of measurement. The observation light is selected such that the observation light includes a component that can be reflected from the object to be measured. The measurement light and the observation light are thus applied independently to the object to be measured, through a common objective lens, and accordingly improvement of the precision in measurement of the optical characteristic and facilitation of focusing on the object to be measured are achieved simultaneously.

The invention provides a large-diameter paraboloidal mirror detecting system, comprising a Fizeau interferometer, a high precision plane reflector, a detected paraboloidal mirror, an electrically controlled translation platform and a computer control system, wherein, the plane deflector realizes autocollimation detection to the central part of the paraboloidal mirror, and then the plane deflector is removed; the electrically controlled translation platform is controlled through the computer to move the Fizeau interferometer, so that reference spheric wave fronts of different curvature radiuses generated by a standard lens can be matched with a corresponding annular region outside the diameter of the plane deflector of a detected paraboloid, and phase data corresponding to resolvable interference fringes can be extracted through Fizeau interferometer data processing software on the computer system; acquired sub-aperture test data can be processed by the annular sub-aperture 'stitching' algorithm, and data acquired from the autocollimation detection of the plane deflector undergoes a full aperture wave front reconstruction to acquire surface shape information of the detected paraboloid. The large-diameter paraboloidal mirror detecting system provides an effective detecting means for the development of a large-diameter paraboloidal mirror and an ultra-large-diameter paraboloidal mirror, and has higher application value.

A method for qualifying and/or manufacturing an optical surface includes:

• • arranging a first substrate having a first surface and a second surface opposite the first surface in a beam path of a first incident beam with the first surface facing towards the first incident beam, and taking an interferometric measurement of the second surface;
  • arranging the first substrate in the beam path of the first incident beam with the second surface facing towards the first incident beam, and taking an interferometric measurement of the second surface;
  • arranging a third surface of a second substrate in a beam path of a second incident beam, and taking an interferometric measurement of the third surface;
  • arranging the third surface of the second substrate and the first substrate in the beam path of the second incident beam, and taking an interferometric measurement of the third surface.

Provided is a measurement method or apparatus that can reduce the time for measuring the shape of an entire test surface. Each of a plurality of measurement ranges is set so that one measurement range overlaps a portion of at least another measurement range to form an overlap region, each measurement range being a portion of the test surface. Then, the shape of the test surface is measured at a first resolution in a first measurement range among the plurality of measurement ranges, and is measured at a second resolution in a second measurement range. Pieces of data of the shapes of the test surface in the plurality of measurement ranges are stitched together using the resulting measurement data to calculate the shape of the test surface.

The invention discloses a heliostat calibration method for a solar power station. The heliostat calibration method comprises the following steps of: obtaining a deviation ei between a heliostat reflective light-spot center position and a receiver center through the movement of an image sensor, and controlling a heliostat to rotate to a nominal position; comparing the distance deviation ei with a set deviation value di so as to judge the deviation size of the heliostat; when the deviation of the heliostat is smaller, just calibrating fewer calibration errors; and when the deviation of the heliostat is larger, then calibrating more calibration errors. The invention further discloses a heliostat calibration system using the calibration method. According to the heliostat calibration method and the heliostat calibration system, disclosed by the invention, the image sensor is used for determining the heliostat reflective light-spot center position, so that the calibration action is fast, the mechanical error is small and the calibration precision is improved. Furthermore, according to the heliostat calibration method and the heliostat calibration system, disclosed by the invention, the calibration is carried out in a manner of determining calibration parameters through firstly judging the deviation size of the heliostat, so that the calibration efficiency and the calibration precision are improved.

Cavity enhanced absorption spectroscopy systems and methods for detecting trace gases using a resonance optical cavity, which contains a gas mixture to be analyzed, and a laser coupled to the cavity by optical feedback. The cavity has any of a variety of configurations with two or more mirrors, including for example a linear cavity, a v-shaped cavity and a ring optical cavity. The cavity will have multiple cavity resonant modes, or a comb of frequencies spaced apart, as determined by the parameters of the cavity, including the length of the cavity, as is well known. Systems and methods herein also allow for optimization of the cavity modes excited during a scan and/or the repetition rate.

The invention relates to a device for testing focal spots focused by a solar parabolic concentrator. The device takes full advantage of the linear beams generated by a semiconductor laser and tests the focused focal spots through reflection of a parabolic mirror. The device is simple and the method is feasible and is widely applied to various parabolic concentrators. The device belongs to the technical field of solar energy utilization.

A surface-distortion measuring device and a surface-distortion measuring method can quantitatively, rapidly, and highly accurately measure and evaluate surface-distortion distribution at all of observable points on a specular or semi-specular surface of a measurement target. The device includes pattern displaying means 2 capable of switching and displaying a plurality of kinds of light-and-shade patterns 5, capturing means 3 for capturing mirror images, reflected in the specular or semi-specular surface of a measurement target 1, of the plurality of light-and-shade patterns displayed on the pattern displaying means, and surface-distortion distribution calculating means 10 for performing image processing on the captured mirror images of the plurality of light-and-shade patterns to calculate surface-distortion distribution of the measurement-target surface.

An automated deflectometry system and method for assessing the quality of a reflective surface for use in a concentrating solar power plant. The deflectometry system comprises a holding fixture for mounting a heliostat reflector opposite a target screen having a known pattern. Digital cameras embedded in the target screen take pictures of the known pattern as reflected in the surface of the reflector. Image processing software then detects the features of the pattern in the reflector images and calculates the slope profile of the reflective surface. The slope field can be calculated by comparing the images of the reflective surface to those of a reference surface. Based on the slope profile of the reflective surface, a ray tracing calculation can be performed to simulate flux as reflected from the reflective surface onto a receiver and a quality metric can be ascribed to the heliostat reflector. The result of the quality assessment can displayed using a graphical user interface on an automated assembly line.

The present invention provides a method of measuring a shape of a target surface, including a step of obtaining shape data by causing a stage which holds the target surface to rotate the target surface about a rotation axis, positioning each of a plurality of partial regions of the target surface in a field of view of a measurement apparatus, and causing the measurement apparatus to measure each of the plurality of partial regions, a step of obtaining, for each of a plurality of partial contour regions, a central position of the target surface using data of a contour included in the shape data, and a step of obtaining, based on the obtained plurality of central positions, a position of the rotation axis of the target surface in positioning each of the plurality of partial regions.

The present invention provides a measurement apparatus that illuminates a surface to be tested having an aspheric surface using light beams that form spherical waves to measure a figure of the surface to be tested, including a detection unit configured to detect interference patterns between light beams from the surface to be tested and light beams from a reference surface, and a controller configured to control processing for obtaining a figure of the surface to be tested based on the interference patterns detected by the detection unit.

A diffractive optical element (50) with a substrate (52) and a diffractive structure pattern (54) arranged thereon. The diffractive structure pattern is configured to convert a plane or spherical input wave (42) radiated thereon into at least four separate output waves, wherein at least one of the output waves is a non-spherical wave (56), at least a further one of the output waves is a spherical wave (58; 70) and at least two further ones of the output waves respectively are a plane wave (60) or a spherical wave (72, 74).

A new family of truly nonsymmetric optical systems that exploit a new fabrication degree of freedom enabled by the introduction of slow-servos to diamond machining; surfaces whose departure from a sphere varies both radially and azimuthally in the aperture, and associated design method.

Coordinate transformation parameters are adopted at the time of synthetically combining partial measurement data so as to eliminate the setting error that can get in when a workpiece is set in position on a measuring machine. Then, a shape parameter is adopted to estimate the approximate error shape of the entire workpiece and the approximate error shape is removed from the measurement data. As a result, the residuals are reduced if the measurement data are those of three-dimensional sequences of points. Differences are small when small residuals are compared so that the mismatch is reduced. According to the present invention, the entire measurement data can be synthetically combined without using the conventional concept of overlap.

A common-path, point-diffraction, phase-shifting interferometer uses a half wave plate having a diffractive element, such as pin hole. A coherent, polarized light source simultaneously generates a reference beam from the diffractive element and an object beam from remaining portions of the light going through the half wave plate. The reference beam has a nearly spherical wavefront. Each of the two beams possesses a different polarization state. The object and reference beams are then independently phase modulated by a polarization sensitive phase modulator that shifts phase an amount depending on applied voltage and depending on polarization state of the incident light. A polarizer is then used to provide the object and reference beams in the same polarization state with equal intensities so they can interfere to create an interferogram with near unity contrast.

A surface shape measurement method that divides a surface shape of an object (107) into a plurality of partial regions (201, 202, 203, 204) to obtain partial region data and that stitches the partial region data to measure the surface shape of the object, and the method includes the steps of calculating sensitivity of an error generated by a relative movement between the object and a sensor (110) for each of the partial regions, dividing the surface shape of the object into the plurality of partial regions to obtain the partial region data, obtaining the partial region data, calculating an amount corresponding to the error using the sensitivity, correcting the partial region data using the amount corresponding to the error, and stitching the corrected partial region data to calculate the surface shape of the object.