Optics: measuring and testing – By polarized light examination – With light attenuation
Patent
1988-01-20
1989-07-04
Evans, F. L.
Optics: measuring and testing
By polarized light examination
With light attenuation
250201, 250372, 356376, 356381, 356328, G01B 1106, G01B 1124
Patent
active
048446173
ABSTRACT:
A confocal measuring microscope including a spectrometer and autofocus system sharing common optical elements in which the intensity of light entering the spectrometer from a particular spot on a workpiece is used to determine a focus condition for the same spot. The microscope includes at least one light source, an illumination field stop, and a microscope objective that images the stop onto a workpiece supported by a movable platform. The objective also forms an image of the illuminated portion of the object. An aperture in a second stop and intersecting the image plane passes light from part of the image to the spectrometer, while viewing optics are used to view the image. In one embodiment, a detector is placed at the zero order position, while in another embodiment a laser is placed at the zero order position. In the later embodiment an integrator circuit connected to the detector array replaces the zero order detector for measuring the total intensity of light entering the spectrometer. A best focus condition occurs when the total intensity is a maximum for a positive confocal configuration, i.e. where source and detector are on opposite sides of their respective field stops from said workpiece, and a minimum for a negative confocal configuration, i.e. where the source and workpiece are on the same side of a reflective illumination field stop with aperture. The movable platform may be scanned axially to achieve and maintain object focus as the object is scanned transversely.
REFERENCES:
patent: 3912922 (1975-10-01), Lacotte et al.
patent: 4674883 (1987-06-01), Baurschmidt
patent: 4676647 (1987-06-01), Kikkawa et al.
D. K. Hamilton et al., "Surface Profile Measurement Using the Confocal Microscope", Journal of Applied Physics, 53(7), Jul., 1982, pp. 5320-5322.
T. Wilson et al., Theory and Practice of Scanning Optical Microscopy, Academic Press, (London), 1984, see especially pages 123-139.
G. Hausler et al., "Simple Focusing Criterion", Applied Optics, vol. 23, No. 15, Aug. 1, 1984, pp. 2468-2469.
J. M. Lerner et al., "Aberration Corrected Holographically Recorded Diffraction Gratings", SPIE vol. 240--Periodic Structures, Gratings, Moire Patterns and Diffraction Phenomena, 1980, pp. 72-81.
T. R. Corle et al., "Distance Measurements by Differential Confocal Optical Ranging", Applied Optics, vol. 26, No. 12, Jun. 15, 1987, pp. 2416-2420.
L. Reimer et al., "Lock-In Technique for Depth-Profiling and Magnetooptical Kerr Effect Imaging in Scanning Optical Microscopy", Scanning, vol. 9, No. 1, 1987, pp. 17-25.
Adams Arnold
Fein Michael E.
Kelderman Herman F.
Loh Alan E.
Neukermans Armand P.
Evans F. L.
Schneck Thomas
Tencor Instruments
LandOfFree
Confocal measuring microscope with automatic focusing does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Confocal measuring microscope with automatic focusing, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Confocal measuring microscope with automatic focusing will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-849299