Optics: measuring and testing – By dispersed light spectroscopy – Utilizing a spectrometer
Patent
1997-01-21
1998-05-12
Font, Frank G.
Optics: measuring and testing
By dispersed light spectroscopy
Utilizing a spectrometer
356351, G01B 902
Patent
active
057514275
ABSTRACT:
Optical method and means for high-speed measurement of the distance between two surfaces, the first of which (25, 25a) is part of a substantially transparent element (20, 20a) and the second of which (35, 35a) is part of a test object (30, 30a). In a first step, a lens (3) directs a light beam (2) through a polarizing component (4) towards the first surface at an oblique angle of incidence. The measurement beam may be positioned on the surface under test (35, 35a) with an in-line optical system or a normal incidence one. In a next step, the polarized light beam (5) reflects back through the transparent element by means of the combined effect of reflections from the first surface of the transparent element and from the surface of the test object (30). In a further step, a polarization-sensitive intensity detector (12) and a phase detector (13) measure the strength and relative phase of the polarization components defined by the plane of incidence. A computer (99) then analyzes these measured parameters to determine the size of the gap between the two surfaces (25, 35). An additional method and means are provided to measure the complex index of refraction of the object surface (35) by changing the gap between the surfaces (25, 35).
REFERENCES:
patent: 3855625 (1974-12-01), Garnier et al.
patent: 4593368 (1986-06-01), Fridge et al.
patent: 4606638 (1986-08-01), Sommargren
patent: 4762414 (1988-08-01), Grego
patent: 5170049 (1992-12-01), De Jonge et al.
patent: 5218424 (1993-06-01), Sommargren
patent: 5280340 (1994-01-01), Lacey
patent: 5557399 (1996-09-01), de Groot
L-Y. Zhu et al., "Measurement of Head/Disk Spacing With a Laser Interferometer," IEEE Transactions On Magnetics, vol. 24, No. 6, pp. 2739-2741 (Nov. 1988).
W. Stone, "A Proposed Method for Solving Some Problems in Lubrication," The Commonwealth Engineer, pp. 115-122 (Nov. 1, 1921).
M. V. Mantravadi, "Chapter 1--Newton, Fizeau, and Haidinger Interferometers," Optical Shop Testing, Second Edition, pp. 1-48, John Wiley & Sons, Inc. (1992).
A. Nigam, "A Visible Laser Interferometer for Air Bearing Separation Measurement to Submicron Accuracy," Transactions of the ASME, vol. 104, pp. 60-65 (Jan. 1982).
T. Ohkubo et al., "Accurate Measurement of Gas-Lubricated Slider Bearing Separation Using Visible Laser Interferometry," Transactions of the ASME, vol. 110, pp. 148-155 (Jan. 1988).
G. L. Best et al., "Precise Optical Measurement Of Slider Dynamics," IEEE Transactions on Magnetics, vol. MAG-22, No. 5, pp. 1017-1018 (Sep. 1986).
B. Bhushan, "Tribology and Mechanics of Magnetic Storage Devices," Springer-Verlag, pp. 765-797, date not available.
C. Lin et al., "Real time interferometric ellipsometry with optical heterodyne and phase lock-in techniques," Applied Optics, vol. 29, No. 34, pp. 5159-5162 (Dec. 1990).
H. F. Hazebroek et al., "Interferometric ellipsometry," Journal of Physics E: Scientific Instruments, pp. 822-826, vol. 6 (1973).
T. Smith, "An Automated Scanning Ellipsometer," Surface Science, pp. 212-220, vol. 56 (1976).
R. F. Spanier, "Ellipsometry--A Century Old New Technique," Reprinted from Industrial Research, (Sep. 1975).
D. P. Pilipko et al., "Interference Ellipsometer," 8164 Instruments and Experimental Techniques, pp. 951-952, vol. 26, No. 4, Part 2 (Jul.-Aug. 183).
C. Lacey et al., "Interferometric Measurement of Disk/Slider Spacing: The Effect of Phase Shift on Reflection," IEEE Transactions on Magnetics, vol. 29, No. 6, pp. 3906-3908 (Nov. 1993).
L. Singher et al., "Ellipsometry with a Stabilized Zeeman Laser," Applied Optics, vol. 29, No. 16, pp. 2405-2408 (Jun. 1990).
J. M. Fleischer et al., "Infrared Laser Interferometer for Measuring Air-Bearing Separation," IBM J. Res. Develop., pp. 529-533 (Nov. 1974).
IDEMA Sub 2-Microinch Fly Height Workshop Proceedings, pp. 31-108, date not available.
R. Pavlat, "Flying Height Measurement Systems and Slider Absorption(k)," and other articles published in IDEMA Insight, vol. VII, No. 5 (Sep./Oct. 1994).
Y. Sato et al., "The Koyo FM2000 Fly Height Tester," IDEMA Sub 2-Microinch Fly Height Workshop Proceedings, pp. 31-44, date not available.
D. H. Veillard, "New Possibilities in Head-Disk Separation Movement," IDEMA Sub 2-Microinch Fly Height Workshop Proceedings, pp. 47-55, date not available.
C. Lacey, "A New Method for Measuring Flying Height Dynamically," IDEMA Sub 2-Microinch Fly Height Workshop Proccedings, pp. 59-74, 1992.
T. McMillan, "Ultra Low Flying Height Measurements Using Laser Interferometry and Fringe Intensity Determination," IDEMA Sub 2-Microinch Fly Height Workshop Proceedings, pp. 93-108, May 1993.
G. L. Best, "Comparison Of Optical And Captive Measurements Of Slider Dynamics," IEEE Transactions on Magnetics, vol. MAG-23, No. 5, pp. 3453-3455 (Sep. 1987).
Caufield Francis J.
Font Frank G.
Merlino Amanda
Zygo Corporation
LandOfFree
Optical gap measuring apparatus and method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Optical gap measuring apparatus and method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical gap measuring apparatus and method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-987162