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US3735534A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for controlled lapping of optical surfaces to correct deviations from desired contours
Assignee: ALTAIR SCIENT Inc
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Filing: 1971-02-10
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Granted: 1973-05-29
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Expires: 1991-02-10
Abstract
Abstract Apparatus for scanning an aspheric optical surface in a spiral pattern and lapping with short strokes is provided by rotating a table supporting the workpiece at a controlled rate, radially moving an arm carriage, and cyclically driving the arm on the carriage with a crank to produce short lapping strokes along the spiral scanning path. A program prepared from contour deviation plots along several diameters of the workpiece (made by knifeedge measurement techniques) control the rate of rotation of the workpiece inversely proportional to deviations from the desired surface contour. After repeated use of one program has reduced deviations by at least half, measurements are again made and a new program is prepared. Each iteration of a given program is run at a rate which assures completion of the entire program in an interval of time during which the rate of material removal will not vary by more than 10 percent.
Inventors
- 👤 M Mayo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 03:32
CPC Classifications
B; B24; B24B; B24B13/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
304 words
Apparatus for polishing an optical surface which comprises: means for supporting a workpiece on which an optical surface is to be polished, first drive means for rotating said means for supporting said workpiece including means for controlling the rate at which said supporting means is rotated to be a function of the radial position of said pad relative to the center of rotation of said supporting means, means for carrying a lapping pad in contact with said surface of said workpiece at a controlled pressure in all contact positions of said pad on said surface, means for imparting at least two types of relative motion of said pad on said surface, including means for superimposing at a constant cyclic rate a first cyclic motion to produce lapping strokes on pad carrying drive means driven at a constant linear rate to provide a second scanning motion over a predetermined scanning pattern which assures lapping all of said surface such that the total time during which said pad may be in contact with each surface point is the same for one complete scanning pattern; said controlling means includes a variable speed motor-drive means responsive to a control signal for controlling the rate at which said workpiece-supporting means is rotated, and means responsive to said linear drive means of said pad-carrying means for producing a control signal with an amplitude proportional to the radial position of said pad relative to the center of rotation of said workpiece-supporting means; and means for varying the rate of at least one of said two types of relative motion during one complete scanning pattern, whereby the total time during which said pad is actually in contact with a given surface point during one complete scanning pattern may be varied comprised of means for adding a variable signal to said control signal.
Claim 2
Dependent Claim
304 words
Apparatus for polishing an optical surface which comprises: means for supporting a workpiece on which an optical surface is to be polished, first drive means for rotating said means for supporting said workpiece including means for controlling the rate at which said supporting means is rotated to be a function of the radial position of said pad relative to the center of rotation of said supporting means, means for carrying a lapping pad in contact with said surface of said workpiece at a controlled pressure in all contact positions of said pad on said surface, means for imparting at least two types of relative motion of said pad on said surface, including means for superimposing at a constant cyclic rate a first cyclic motion to produce lapping strokes on pad carrying drive means driven at a constant linear rate to provide a second scanning motion over a predetermined scanning pattern which assures lapping all of said surface such that the total time during which said pad may be in contact with each surface point is the same for one complete scanning pattern; said controlling means includes a variable speed motor-drive means responsive to a control signal for controlling the rate at which said workpiece-supporting means is rotated, and means responsive to said linear drive means of said pad-carrying means for producing a control signal with an amplitude proportional to the radial position of said pad relative to the center of rotation of said workpiece-supporting means; and means for varying the rate of at least one of said two types of relative motion during one complete scanning pattern, whereby the total time during which said pad is actually in contact with a given surface point during one complete scanning pattern may be varied comprised of means for adding a variable signal to said control signal.
Claim 3
Dependent Claim
77 words
Apparatus as defined in claim 1 including means for storing contour deviation data for a given optical surface to be polished, said data representing the measured deviation of said optical surface from a desired contour at the beginning of a scanning pattern, means for reading said stored data in synchronism with said pattern scanning motion of said pad, and means for producing said variable control signal from said stored contour deviation data read by said reading means.
Claim 4
Independent Claim
188 words
An apparatus for polishing an optical surface which comprises: means for supporting a workpiece on which an optical surface is to be polished; first drive means for rotating said means for supporting said workpiece; means for carrying a lapping pad in contact with said surface of the workpiece at a controlled pressure in all contact positions of said pad on said surface; means for imparting at least two types of relative motion between said pad and surface including pad-carrying drive means for providing a first scanning movement of the pad in a predetermined pattern over all of said surface and stroking drive means for superimposing cyclic stroking motion on the motion produced by the pad-carrying drive means; control means including means responsive to the radial position of the pad relative to the center of rotation of said workpiece supporting means for producing a control signal with an amplitude proportional to said position and means for applying said signal to control at least one Of said drive means whereby the lapping period of contact of the pad with each surface point is the same for each complete scanning pattern.
Claim 5
Independent Claim
188 words
An apparatus for polishing an optical surface which comprises: means for supporting a workpiece on which an optical surface is to be polished; first drive means for rotating said means for supporting said workpiece; means for carrying a lapping pad in contact with said surface of the workpiece at a controlled pressure in all contact positions of said pad on said surface; means for imparting at least two types of relative motion between said pad and surface including pad-carrying drive means for providing a first scanning movement of the pad in a predetermined pattern over all of said surface and stroking drive means for superimposing cyclic stroking motion on the motion produced by the pad-carrying drive means; control means including means responsive to the radial position of the pad relative to the center of rotation of said workpiece supporting means for producing a control signal with an amplitude proportional to said position and means for applying said signal to control at least one Of said drive means whereby the lapping period of contact of the pad with each surface point is the same for each complete scanning pattern.
Claim 6
Dependent Claim
71 words
Apparatus as defined in claim 3 in which the pad carrying means is driven at a constant linear rate, the stroking drive means is driven at a constant cyclic rate, said first drive means includes a variable speed motor responsive to said control signal whereby the rate of rotation of said motor is directly proportional to the radial position of the pad relative to the center of the workpiece supporting means.
Claim 7
Dependent Claim
135 words
An apparatus according to claim 3 further including means for producing a variable signal including: means for storing contour deviation data for a given optical surface to be polished, said data representing the measured deviation of said optical surface from a desired contour at the beginning of a scanning pattern; means for reading said stored data in synchronism with said pattern scanning motion of said pad; means for producing said variable control signal from said stored contour deviation data read by said reading means; and means for adding said variable signal to said control signal to produce a variable control signal whereby the total time during which said pad is in contact with a surface point deviating from the desired contour during one complete scanning pattern is varied in response to said variable control signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-05-28 | 1976-11-27 | 1977-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-28 | 1980-11-27 | 1981-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-28 | 1984-11-27 | 1985-05-29 | $7700.00 | Window Closed / Lapsed |