WO1999005499A1 - Cartographe de la qualite d'image pour verres progressifs - Google Patents

Cartographe de la qualite d'image pour verres progressifs Download PDF

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Publication number
WO1999005499A1
WO1999005499A1 PCT/US1998/014494 US9814494W WO9905499A1 WO 1999005499 A1 WO1999005499 A1 WO 1999005499A1 US 9814494 W US9814494 W US 9814494W WO 9905499 A1 WO9905499 A1 WO 9905499A1
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WO
WIPO (PCT)
Prior art keywords
lens
detection system
testing instrument
image quality
optical testing
Prior art date
Application number
PCT/US1998/014494
Other languages
English (en)
Inventor
Russell Chipman
Jonathan J. Drewes
James B. Hadaway
Original Assignee
Innotech, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Innotech, Inc. filed Critical Innotech, Inc.
Priority to AU84002/98A priority Critical patent/AU8400298A/en
Publication of WO1999005499A1 publication Critical patent/WO1999005499A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
    • G01M11/02—Testing optical properties
    • G01M11/0242—Testing optical properties by measuring geometrical properties or aberrations
    • G01M11/0257—Testing optical properties by measuring geometrical properties or aberrations by analyzing the image formed by the object to be tested
    • G01M11/0264—Testing optical properties by measuring geometrical properties or aberrations by analyzing the image formed by the object to be tested by using targets or reference patterns
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
    • G01M11/02—Testing optical properties
    • G01M11/0228—Testing optical properties by measuring refractive power
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
    • G01M11/02—Testing optical properties
    • G01M11/0242—Testing optical properties by measuring geometrical properties or aberrations
    • G01M11/0278—Detecting defects of the object to be tested, e.g. scratches or dust

Definitions

  • the present invention relates to optical testing instruments and more particularly to an automated optical testing instrument capable of measuring the image quality over the surface of a progressive addition eyeglass lens.
  • measurements of power, astigmatism and prism can be made manually at certain locations on a lens (generally with about a 3 millimeter subaperture diameter) using commercially-available lensometers. otherwise known as focimeters. Measurement of resolution is typically made using a test bench setup through the inspection of an image formed by a PAL of an Air Force bar target object at infinity using a microscope. While these instruments and methods do provide some basic information about the PAL, they fail to give precise, comprehensive image quality information that would be very useful to the PAL designer and/or manufacturer. Moreover, known instruments and methods do not allow for fully automated mapping of the power, astigmatism, prism and Modulation Transfer Function (MTF) over the entire surface of a PAL.
  • MTF Modulation Transfer Function
  • the present invention provides an improved instrument and method for measuring image quality of eyeglass lenses, including PALs. designed to overcome the disadvantages associated with the prior art.
  • PALs PALs.
  • the instrument includes an illumination system for presenting a collimated beam of light of appropriate size to a test lens, a positioning system for rotating the test lens so that different areas on the lens are illuminated.
  • a zoom lens for focusing the beam at a constant system effective focal length once it passes through a particular subaperture of the test lens, a detection system for recording and measuring the image quality of the lens, and an alignment boom for conveying the zoom lens and the detection system such that the optical axis of the zoom/detection system remains aligned with the beam exiting the test lens.
  • the best-focus power, magnitude and direction of astigmatism, magnitude and direction of prism and MTF at best-focus are measured.
  • the MTF is obtained through a Fourier transform of the measured point-spread function (PSF).
  • a map of a lens is then constructed by sampling the lens at a plurality of subaperture locations. Surface, contour, and text plots are made of the power, astigmatism, prism and MTF. as well as astigmatism and prism vector plots.
  • FIG. 1 is a schematic view of the Eyeglass Image Quality Mapper (EIQM) according to the present invention
  • FIG. 2 is an exemplary plot of radial variance versus test lens power, generated by the EIQM of FIG. 1 and used in the measurement of best-focus power;
  • FIG. 3 is an exemplary plot of the ratio of maximum image width to minimum image width versus test lens power, generated by the EIQM of FIG. 1 and used in the measurement of the magnitude of astigmatism;
  • FIG. 4 is a schematic view illustrating the two rotation axes of the test lens mounting/positioning system, the two rotation axes of the alignment boom, and the two linear movements of the zoom lens;
  • FIG. 5 is a schematic view of a PAL lens illustrating the plurality of locations or subapertures on the lens at which image quality measurements are made using the EIQM of FIG. 1 ;
  • FIG. 6A is a series of schematic views of a test lens under rotation, illustrating the beam deviation resulting when the front and back surfaces of a PAL are not parallel to one another;
  • FIG. 6B is a series of schematic views of a test lens under rotation, similar to those of FIG. 6A. illustrating the use of a boom assembly in the EIQM of FIG. 1. whose rotation point is at the back surface of the PAL and that carries the zoom lens and detection system;
  • FIG. 7 is a plot of zoom lens position versus test lens power for the EIQM of FIG. 1. for each of the lenses comprising the zoom lens;
  • FIGS. 8 and 9 are examples of through- focus images of a minimally astigmatic region and an astigmatic region of the PAL, respectively, generated by the EIQM of FIG. 1 ;
  • FIG. 10 is a schematic view of a PAL, illustrating the PSF over the surface of the lens at various locations;
  • FIGS. 11 A, 1 IB, 1 IC, 1 ID, 1 IE and 1 IF, respectively, are a contour plot of the best focus power, a contour plot of the astigmatism magnitude, a vector plot of the astigmatism angle, a contour plot of the prism magnitude, a vector plot of the prism angle, and a contour plot of the normalized MTF at 20/20 for LENS A. generated by the EIQM of FIG. 1 ;
  • FIGS. 12A, 12B, 12C, 12D, 12E and 12F. respectively, are a contour plot of the best focus power, a contour plot of the astigmatism magnitude, a vector plot of the astigmatism angle, a contour plot of the prism magnitude, a vector plot of the prism angle, and a contour plot of the normalized MTF at 20/20 for LENS B. generated by the EIQM of FIG. 1;
  • FIGS. 13A and 13B are full plots of the MTF of different subapertures of LENS A, generated by the EIQM of FIG. 1 ; and
  • FIGS. 14A. and 14B are. respectively, a three dimensional map of normalized MTF at 20/20. and a numerical plot of normalized MTF at 20/20 versus subaperture location, generated by the EIQM of FIG. 1.
  • the optical testing instrument 10 or Eyeglass Image Quality Mapper generally includes: (a) an illumination system 12 for presenting a collimated beam of light of appropriate size to a test lens; (b) a test lens mounting/positioning system 14 capable of rotating the test lens so that different areas on the lens are illuminated; (c) a zoom lens 16 for focusing the beam at a constant system effective focal length (EFL) once it passes through a particular subaperture of the test lens: (d) a detection system 18 for recording and measuring the image quality of the lens; and (e) an alignment boom 20 for conveying the zoom lens and the detection system such that the optical axis of the zoom/detection system remains aligned with the beam exiting the test lens.
  • ETL effective focal length
  • the instrument 10 is preferably coupled to a microprocessor-controlled computer system 22 for controlling the image quality mapper and analyzing the data obtained.
  • a microprocessor-controlled computer system 22 for controlling the image quality mapper and analyzing the data obtained.
  • the power of a PAL is determined from the position of the zoom lens that yields the best image quality. During testing, the zoom lens is moved through a range of positions and the image quality is measured at each position.
  • a useful indication of image quality is the Point Spread Function produced by a lens.
  • the EIQM is its ability to measure the Point Spread Function (PSF) produced by a subaperture of the test lens.
  • the PSF is a measurement of light intensity distribution. In general, a smaller PSF indicates a better image quality than a larger PSF, as larger PSFs result from higher aberrations in the lens.
  • One useful measure of the size of a PSF is the radial variance, which describes the size of the light distribution about its mean position. The following procedure describes how the radial variance can be calculated. First, the centroid of a given image is found. The radial variance is a measure of how tightly the light is distributed about the centroid as a function of the radial distance from the centroid.
  • This quantity or rather, its root-mean-square (RMS) is widely used in both lens design and lens testing to find the location of best-focus.
  • RMS root-mean-square
  • a polynomial is fit to the data, and the power of the zoom lens where the radial variance is a minimum is recorded. This power is the best-focus power, and this is where the final PSF is recorded.
  • a plot of the radial variance versus power is illustrated in FIG. 2. One can see a clear minimum in the radial variance at about 0.35 D.
  • the analysis software used in the EIQM has fit a curve to the data and calculated the minimum to be at 0.3449141 D. This is the best-focus power.
  • the EIQM is also capable of making astigmatism measurements for PALs, both in terms of magnitude and in terms of orientation.
  • Astigmatism When there is significant astigmatism at a particular location on the test lens, two line images will be formed, one at one power setting and one at another. The difference in power between the two line images is defined as the astigmatism magnitude.
  • the angle of the lower-powered line image gives the angle, or axis, of astigmatism.
  • a measure of the image width in one direction is used, rather than the two-dimension radial variance used to find best focus. If the one-dimensional image width along a line through the centroid of an image is measured as a function of the line's angular orientation, a maximum width (along the line image) and a minimum width (across the line image) will be obtained.
  • the ratio of minimum width to maximum width for the plurality of through- focus images taken at a given subaperture on a lens may be plotted against power, as seen in FIG. 3. This ratio varies from 0 for a line image, to 1 for a circular image. Therefore, when there is astigmatism, the two locations on the plot where the ratio approaches 0 correspond to the two line foci. From these two locations, one can calculate the astigmatism magnitude using the difference in power.
  • the best-focus power is found halfway between the two line foci.
  • the location of the best-focus power may not be exactly at the midpoint and should be found using the minimum radial variance discussed above.
  • Lens prism is a measure of how much a beam is deviated from its original path after passing through a certain point on the lens.
  • the customary unit of measure is the prism diopter, which is defined as the lateral displacement of the beam, measured in cm. from its original location on a surface that is 1 m behind the lens. In other words. 1 prism diopter equals 10 milliradians of angular deviation.
  • the EIQM determines the prism at any test location simply by recording the angular position of the boom with respect to the on-axis or zero position (see FIG. 6B).
  • EIQM Modulation Transfer Function
  • MTF Modulation Transfer Function
  • the MTF is simultaneously obtained for all spatial orientations and all spatial frequencies up to the Nyquist limit of the detector used to record the PSF.
  • the EIQM begins with an illumination system 12 designed to present a collimated beam of appropriate size to the test lens 24 from a light source 26.
  • a 543 nm green He-Ne laser is used as the source and is spatially filtered using a 5 micron pinhole.
  • a non-limiting example of a suitable laser for use in the EIQM is as lmW. linearly- polarized 543 nm green He-Ne laser available from Melles Griot, Irvine. California.
  • a broadband source such as a white-light source (e.g. a quartz halogen lamp) or a light emitting diode (e.g. a green LED) may alternatively be used as the light source.
  • a narrowband interference filter e.g. a 550 nm filter
  • Using a laser as a light source offers certain advantages over a broadband light source, including easier alignment, more power, and a more uniform beam. However, because the laser produces so much power, a neutral density filter is preferably located in the illumination system in order to attenuate the beam and prevent saturation of the detection system.
  • the spectral bandwidth of the light source was originally set to 550 ⁇ 10 nm using a broadband light source and a filter, since most eyeglass testing is done at or near 550 nm in order to provide consistency throughout the field. Subsequently, it was determined to change to the 543 nm laser.
  • a collimator 28 is then used to present a collimated beam to the test lens.
  • the collimator includes a 20x microscope objective 30. followed by a pinhole. and then an achromatic lens 32.
  • the achromatic lens 32 used in a prototype of the EIQM is an achromatic doublet that is a combination of a low-dispersion, positive element and a high- dispersion, negative element, cemented together to form a positive lens having essentially no dispersion in the visible spectrum.
  • achromatic doublets exhibit significantly lower amounts of other aberrations (spherical aberration, coma, astigmatism, etc.) than singlets.
  • lens such as an aspheric singlet or an air-spaced doublet
  • Suitable components for the collimator described above are available from Newport, in Irvine California and Spindler-Hoyer, in Milford, Massachusetts.
  • the diameter of the collimated beam is set using an adjustable aperture 34.
  • the beam may be set using one of four apertures (2,3,5, and 7 mm) in a sliding plate. These beam diameters cover the typical range of pupil sizes for the human eye under different illumination conditions. Testing with smaller pupil diameters can be done to either simulate bright viewing conditions or simply to obtain an image quality map with finer detail across the test lens. Testing with larger pupil diameters will simulate darker viewing conditions.
  • an adjustable aperture wheel or adjustable iris can be used in place of the adjustable aperture plate to set the diameter of the beam.
  • the lens 24 under test follows the illumination system, is held by a mounting/positioning system 14, and is illuminated by the collimated beam.
  • a primary objective of the EIQM is to model the way in which the eyeglass lens is used by the human eye.
  • the human eye has a center of rotation, and as the eye rotates, light passing through the eyeglass lens and the pupil forms a set of beams which pivot about the eye " s center of rotation.
  • the mounting/positioning system is designed to rotate the lens about a rotation point 35 behind the back surface of the test lens.
  • a 27 mm radius is used for the rotation of the test lens.
  • the 27 mm radius has been selected because it is consistently used in the relevant literature as an average distance between the center of rotation of the eye and the back vertex of the eyeglass lens; however, the EIQM is capable of making measurements with a varying rotation distance.
  • a lens mount 36 is coupled to a two-axis rotary stage system used to position the test lens so that different areas on the lens are illuminated for measurement.
  • the two-axis rotary stage system comprises two motorized rotary stages. Suitable low-capacity, motorized rotation stages are available from Velmex in Bloomfield, New York.
  • the two-axis rotary stage system is designed such that, if the z-axis is the optical axis, the test lens is capable of rotating about a line parallel to the x-axis and a line parallel to the y-axis in order to simulate the human eye as described above.
  • arrows 40, 42 indicate the two-axis rotation of the lens.
  • a three-prong, self-centering lens holder is utilized for the lens mount (the test lenses are typically un-edged and usually about 76 mm in diameter).
  • a set screw in the mount is used to prevent the prongs from exerting excessive force on the lens.
  • a suitable 80 mm diameter, 3 -prong, self-centering lens mount is available from Melles Griot in Irvine, California.
  • the two-axis rotary stage system for the test lens mounting/positioning system is used to sequentially position the test lens at a pre-assigned list of locations or subapertures on the test lens for making image quality measurements.
  • the specific locations on the test lens are determined by the properties of the lens being tested, the size of the test beam, and the information desired about the test lens. For example, with a typical PAL and a 5 mm diameter test beam, the EIQM has used 103 measurement locations that are spaced more coarsely in the upper distance zone and more finely around the transition and add zones (FIG. 5).
  • the list of lens positions is simply a list of angles (a horizontal angle and a vertical angle for each position) provided to the computer.
  • the angles define how the two-axis rotary stage system 38 should rotate about the eye rotation point for each position.
  • the power, astigmatism (magnitude and angle), prism (magnitude and angle and MTF are calculated and used to measure the image quality across the lens.
  • the spacing between measurement points should preferably be set such that the beam footprints on the lens do not overlap.
  • the above procedure is fully-automated and controlled by the computer 22 of the EIQM.
  • the two rotation axes for the test lens are motorized with limit sensing switches and controlled by the computer.
  • a list of lens positions where testing is to be performed is loaded into the computer.
  • the computer directs the motorized rotary stage system 38 to position the lens sequentially at each of the positions specified so that the appropriate measurements may be taken before the lens is rotated to the next position.
  • the test beam generally is not normally incident upon the front surface of the PAL.
  • the test beam is deviated about the back surface of the PAL and sweeps through a significant angle as it exits the lens.
  • the incident collimated beam 37 and the beam refracted through the lens under test 39 are not parallel to each other.
  • the EIQM overcomes this problem by rotating the zoom lens/detector system on a boom about the point of beam deviation 41 at the test lens (FIG. 4).
  • both the zoom lens and detector system are coupled to the boom and rotate together about the test lens so that light transmitted through the lens under test is transmitted along, or nearly along, the axis of the zoom lens and is incident near the middle of the detection system.
  • the boom is rotated until the image is recentered on the detector.
  • the alignment boom is coupled to a two-axis rotary stage system.
  • the two-axis rotary stage system comprises two motorized rotary stages. Suitable high-capacity motorized rotation stages are available from Velmex in Bloomfield, New York.
  • arrows 46, 48 indicate the two-axis rotation of the boom. As described above, the operation of the boom system is fully-automated and controlled by the computer 22 of the
  • the two rotation axes for the boom are motorized with limit sensing switches and controlled by the computer.
  • the boom is moved by the motorized two-axis rotary stage system 44 to recenter the image on the detection system.
  • the beam will move completely off the active surface of the detection system as the lens is moved to the next measurement point. To prevent this, it may be necessary to track the beam. This refers to the practice of moving only part of the way to the next measurement point, stopping, adjusting the boom to recenter the image, and then proceeding until the next measurement point is reached without losing the beam.
  • an adjustable prism can be placed directly behind the lens to bring the beam back onto the original axis, or a wide field-of-view zoom lens can be used to capture the exiting light beam without the need for movement of the detection system.
  • PALs have a spatially varying power or focal length. That is, different parts of the lens focus at different distances from the progressive lens. Furthermore, some test lenses may have negative powers. Thus, an accessory optical system is used to bring the light to focus. While the problem of varying power could be overcome by using an adjustable translation system to move the detection system along the optical system to focus the image during testing, this is an expensive and complex solution.
  • the effective focal length (EFL) of the optical system consisting of the PAL and the focusing lens also varies.
  • the size of a PSF for a given amount of aberration varies in proportion to the system EFL. Therefore, if the system EFL varies, direct comparison of PSFs from various locations on the lens becomes difficult.
  • the zoom lens includes two elements, a positive achromat 50 followed by a biconcave singlet 52. Suitable elements for the zoom lens, including an 80 mm EFL achromatic doublet lens and a -20 mm EFL biconcave lens, are available from Spindler-Hoyer in Milford, Massachusetts.
  • the zoom lens includes two motorized linear translation stages mounted on the boom.
  • the front, achromat lens of the zoom is coupled to a first, longer stage
  • the rear biconcave lens is coupled to a second, shorter stage , which itself is coupled to the longer stage.
  • This arrangement provides for the adjustment of axial spacing between the PAL and the achromat, and between the achromat and biconcave lens independently, so that the system EFL can be kept constant for varying PAL powers.
  • the linear stages allow the two elements of the zoom lens to move along the optical axis through their centers when zooming. to keep the system EFL constant. Suitable motorized linear translation stages are available from Velmex in Bloomfield, New York.
  • the zoom lens is used to focus the beam on the detection system at a constant system EFL of 605 mm.
  • This focal length produces a diffraction- limited PSF that is large enough for accurate sampling by the detection system.
  • the zoom lens presently utilized in the EIQM can accommodate any PAL power in the range of -0.5 to +2.8 diopters.
  • the zoom system was designed in CodeVTM, of Optical Research Associates, Pasadena, California, by optimizing the axial locations of the two zoom lenses for a series of paraxial lenses of different powers located at the test lens position such that the entire system EFL remained at 605 mm with good image quality (on an image plane fixed with respect to the PAL).
  • the zoom lens is moved through a plurality of designated test positions for each subaperture on the lens, and the image quality is measured by the detection system.
  • the zoom system For example, a three element zoom lens with a larger power range is presently being developed for the EIQM.
  • the detection system includes a camera 62 for measuring the light intensity distribution, commonly referred to as the PSF.
  • the camera utilized in the detection system is preferably a charge coupled device (CCD) camera, which is made up of a two-dimensional array of pixels or detectors.
  • CCD charge coupled device
  • the true PSF of an optical system is a continuous, two-dimensional distribution of light intensity.
  • a CCD charge coupled device
  • a discreet, two-dimensional array of intensity values are obtained, one for each pixel.
  • the spacing and size of the pixels used to sample the PSF must be taken into account when performing calculations on the PSF, such as those used to obtain the
  • MTF MTF.
  • CID charge injection device
  • the primary requirements of the array detector are that it have very low noise and a large dynamic range so that the fine features of the PSF can been seen. An accurate PSF leads to an accurate
  • a 512x512, 14-bit, cooled CCD camera is used with the EIQM.
  • a suitable CCD camera for use in the EIQM is available from Photometries in Tuscon, Arizona.
  • the detection system is a scanning knife edge in front of a single element detector to measure the Line Spread Function (LSF) of an image.
  • LSF Line Spread Function
  • the LSF provides a measure of the width of the image along one axis.
  • Single element detectors such as a silicon photodiode, photomultiplier tubes, thermoelectric detectors, and thermopile detectors, have a single detecting surface with only one output, not an array of detectors like a CCD, and cannot, by themselves, give the spatial distribution of an image.
  • a knife edge, slit, or pinhole must be moved through the image in front of such single-element detectors while their output is sampled in order to determine the spatial distribution of the light.
  • the MTF for a single orientation but at all spatial frequencies can be obtained from a Fourier transformation of the LSF.
  • the scanning knife edge test must be repeated for several orientations (e.g. 0, 45, 90, and 135 degrees) of the knife edge in the transverse plane to obtain a representative data set of the image quality.
  • Best-focus can be located by repeating a set of four LSF measurements as a set of planes along the optical axis, and locating the plane where the average LSF width is minimized. The same data set can be used to determine the magnitude and orientation of the astigmatism.
  • the detection system includes an interferometer capable of measuring image quality associated with a beam near focus, such as a shearing interferometer or a Smartt Point Diffraction Interferometer (PDI).
  • interferometers measure the wavefront aberration associated with an image by interfering two wavefronts derived from the same light source. From the wavefront aberration measurement, the root mean squared (RMS) wavefront aberration can be determined. Best focus can be determined by finding the plane where the RMS wavefront aberration is minimized.
  • RMS root mean squared
  • all of the EIQM components are mounted to an aluminum baseplate.
  • a black plexiglass, light-tight enclosure has been designed to cover the system during operation.
  • On the top of the cover is an access panel that provides access to the test lenses.
  • the EIQM After assembling and aligning the system, the EIQM should be calibrated. To that end, following the initial system assembly and alignment, the EIQM was checked for measured power, image quality/MTF, image centering, and system EFL through the zoom range using a series of high-quality laboratory lenses. The measured powers were all within 1% of the certified values, the images were all diffraction-limited, and remained centered through-focus for each lens to within ⁇ 20 pixels, and the system EFL remained constant to within ⁇ 5 mm. The EFL of the system was measured through the zoom range using a 300 line/inch grating placed before the calibration lenses. The separation of the 0 and ⁇ 1 orders on the CCD were then used to calculate the EFL.
  • the instrument was checked for measured astigmatism.
  • Two single-vision lenses with 1.0D of prescribed astigmatism were used.
  • the astigmatism at the geometrical center of each lens was first measured with a high quality lens testing bench to an accuracy of ⁇ 0.05D.
  • the astigmatism values measured by the EIQM were within ⁇ 0. ID of the calibrated values.
  • the above calibration procedure is preferably carried out an a periodic basis to insure continuing instrument accuracy.
  • the minimum of this fitted curve is then the best-focus (in diopters) for this subaperture.
  • the zoom system is then moved to this position, the power recorded: and a PSF image taken.
  • the angular position of the boom is also recorded to determine the prism.
  • the final image taken may be binned (up to a factor of 10). Binning sums adjacent pixel values so as to yield a smaller image grid. During initial testing, all images taken were appropriately binned to output a 50x50 grid for analysis. When a binning factor of one is used, only the central 50x50 pixels of the CCD are used. This gives the highest resolution for smaller images.
  • FIG. 5 shows an exemplary map that consists of 103 subape ⁇ ure. A more dense sampling is preferably used in the lower portion of the PAL. where the image quality changes more rapidly.
  • the entire testing sequence has been controlled by a VisualBasicTM program which interacts with the motor controller and detection system. To complete a test run with 103 subapertures. it presently takes approximately two hours. The resulting output consists of an ASCII test file containing all of the through-focus data for each subaperture, and a PSF image file for each subaperture.
  • the power for each test subaperture is calculated and recorded during testing. Further data analysis is then performed in order to determine the astigmatism (magnitude and orientation), prism (magnitude and orientation) and MTF at each subaperture. The data obtained can then be plotted to produce a lens map for easy interpretation. For initial testing, only PALs with no prescribed astigmatism were used, so as to measure only the unwanted astigmatism present in the lenses.
  • the through-focus line image width data is used to determine the location, in diopters, of the two line images formed by an astigmatic region of the PAL. This line image width is the image width across a best-fit line divided by the image width along this line.
  • the magnitude and direction of the local lens prism is calculated from the angular positions of the two boom stages.
  • the boom positions are in degrees, and are converted to prism diopters for display.
  • the MTF of that subaperture.
  • the MTF is calculated, with proper scaling, as a function of angular frequency (e.g. cycles/mrad).
  • the value of the MTF (normalized to the diffraction-limited value) at an angular frequency corresponding to 20/20 vision (one arc minute line widths) is then saved for each subaperture.
  • the contour plot in FIG. 12A shows the best-focus power of LENS B over the surface.
  • the power map for LENS A is quite similar (FIG. 1 1 A).
  • this transition from low to high power produces large amounts of astigmatism.
  • FIGS. 1 1B(LENS A) and 12B (LENS B) LENS B
  • LENS B has a wider area of high astigmatism and more astigmatism in the add zone.
  • the astigmatism vector plots show smooth, continuous transitions of magnitude and angle between the upper and lower portions of the lenses (FIGS. 1 IC and 12C).
  • LENS A the MTF is seen to be high in the upper portion of the lens and in the center of the add zone. It drops some in the "channel" connecting these two regions and is very poor in the "wings " on either size of the channel.
  • LENS B the high MTF zone in the upper portion is much smaller and does not come back up very much in the add zone.
  • FIGS. 13A and 13B Two full MTF plots for LENS A are shown in FIGS. 13A and 13B. one from a good portion of the distance zone and one from a highly astigmatic region. There are a total of four curves on each plot for slices out of the 3-D MTF at 0, 90 and ⁇ 45 degrees. The diffraction- limited MTF for a 5 mm pupil diameter at 543 nm is shown as the dashed line.
  • FIGS. 14A and 14B Additional maps and plots that can be automatically generated by the EIQM are shown in FIGS. 14A and 14B.
  • the value of the EIQM is quite apparent from the maps and plots described above, as image quality has been found to change dramatically from one lens design to another. This allows the lens designer, the lens manufacturer, and/or the prescribing doctor to assess accurately and objectively the quality of any given eyeglass lens. Such plots can be generated for any measured quality.
  • the EIQM was described as being able to measure powers in the range of -0.5 to +2.8 D, the zoom lens can be modified to increase the measurable powers.
  • the EIQM is particularly adapted for measuring the image quality of PALs, it can certainly be used to measure the image quality of any type of eyeglass lens, as long as the power and the astigmatism of the lens are within the measurement range of the system. It is. therefore, to be understood that within the scope of the appended claims, this invention can be practiced otherwise than as specifically described.

Abstract

L'invention concerne un instrument et un procédé d'essai optique d'une lentille pour lunettes, y compris des lentilles d'addition progressives, destinés à réaliser des mesures de la qualité d'image. L'instrument comprend un système d'éclairage pour diriger un faisceau lumineux vers une lentille d'essai, un système de positionnement de lentille pour faire pivoter la lentille d'essai de manière à illuminer ses différentes zones, un objectif zoom pour focaliser le faisceau à une longueur focale effective constante, un système de détection pour enregistrer et mesurer la qualité d'image de la lentille d'essai, et une perche d'alignement pour acheminer l'objectif zoom et le système de détection de sorte que l'axe optique reste aligné avec le faisceau dirigé sur la lentille d'essai. L'instrument est entièrement automatisé et peut mesurer la puissance, l'astigmatisme, le prisme et la fonction de transfert de modulation, à divers emplacements sur la surface de la lentille.
PCT/US1998/014494 1997-07-24 1998-07-13 Cartographe de la qualite d'image pour verres progressifs WO1999005499A1 (fr)

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AU84002/98A AU8400298A (en) 1997-07-24 1998-07-13 Image quality mapper for progressive eyeglasses

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US5382497P 1997-07-24 1997-07-24
US60/053,824 1997-07-24

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CN106404357A (zh) * 2016-11-11 2017-02-15 上海航天控制技术研究所 一种光学透镜焦距自动测试系统及自动测试方法
WO2018175845A1 (fr) * 2017-03-23 2018-09-27 Johnson & Johnson Surgical Vision, Inc. Procédés et systèmes de mesure de la qualité d'image
US10646329B2 (en) 2016-03-23 2020-05-12 Johnson & Johnson Surgical Vision, Inc. Ophthalmic apparatus with corrective meridians having extended tolerance band
US10649234B2 (en) 2016-03-23 2020-05-12 Johnson & Johnson Surgical Vision, Inc. Ophthalmic apparatus with corrective meridians having extended tolerance band
US11013594B2 (en) 2016-10-25 2021-05-25 Amo Groningen B.V. Realistic eye models to design and evaluate intraocular lenses for a large field of view
US11282605B2 (en) 2017-11-30 2022-03-22 Amo Groningen B.V. Intraocular lenses that improve post-surgical spectacle independent and methods of manufacturing thereof
DE102022118646B3 (de) 2022-07-26 2024-02-01 Hochschule Bremen, Körperschaft des öffentlichen Rechts Verfahren und Vorrichtung zur Analyse eines oder mehrerer Brillengläser

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CN104122078A (zh) * 2014-08-08 2014-10-29 中国科学院光电技术研究所 一种近眼显示光学镜头像质的评价方法
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US10670885B2 (en) 2016-03-23 2020-06-02 Johnson & Johnson Surgical Vision, Inc. Ophthalmic apparatus with corrective meridians having extended tolerance band with freeform refractive surfaces
US11123178B2 (en) 2016-03-23 2021-09-21 Johnson & Johnson Surgical Vision, Inc. Power calculator for an ophthalmic apparatus with corrective meridians having extended tolerance or operation band
US10649234B2 (en) 2016-03-23 2020-05-12 Johnson & Johnson Surgical Vision, Inc. Ophthalmic apparatus with corrective meridians having extended tolerance band
US11231600B2 (en) 2016-03-23 2022-01-25 Johnson & Johnson Surgical Vision, Inc. Ophthalmic apparatus with corrective meridians having extended tolerance band with freeform refractive surfaces
US10712589B2 (en) 2016-03-23 2020-07-14 Johnson & Johnson Surgical Vision, Inc. Ophthalmic apparatus with corrective meridians having extended tolerance band by modifying refractive powers in uniform meridian distribution
US11291538B2 (en) 2016-03-23 2022-04-05 Johnson & Johnson Surgical Vision, Inc. Ophthalmic apparatus with corrective meridians having extended tolerance band
US11249326B2 (en) 2016-03-23 2022-02-15 Johnson & Johnson Surgical Vision, Inc. Ophthalmic apparatus with corrective meridians having extended tolerance band
US10646329B2 (en) 2016-03-23 2020-05-12 Johnson & Johnson Surgical Vision, Inc. Ophthalmic apparatus with corrective meridians having extended tolerance band
US11013594B2 (en) 2016-10-25 2021-05-25 Amo Groningen B.V. Realistic eye models to design and evaluate intraocular lenses for a large field of view
CN106404357A (zh) * 2016-11-11 2017-02-15 上海航天控制技术研究所 一种光学透镜焦距自动测试系统及自动测试方法
WO2018175845A1 (fr) * 2017-03-23 2018-09-27 Johnson & Johnson Surgical Vision, Inc. Procédés et systèmes de mesure de la qualité d'image
US10739227B2 (en) 2017-03-23 2020-08-11 Johnson & Johnson Surgical Vision, Inc. Methods and systems for measuring image quality
US11385126B2 (en) 2017-03-23 2022-07-12 Johnson & Johnson Surgical Vision, Inc. Methods and systems for measuring image quality
US11282605B2 (en) 2017-11-30 2022-03-22 Amo Groningen B.V. Intraocular lenses that improve post-surgical spectacle independent and methods of manufacturing thereof
US11881310B2 (en) 2017-11-30 2024-01-23 Amo Groningen B.V. Intraocular lenses that improve post-surgical spectacle independent and methods of manufacturing thereof
DE102022118646B3 (de) 2022-07-26 2024-02-01 Hochschule Bremen, Körperschaft des öffentlichen Rechts Verfahren und Vorrichtung zur Analyse eines oder mehrerer Brillengläser

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