Patent US3867038A successfully refreshed from Google Patents.
US3867038A
Expired / Lapsed
US
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Optical alignment system
Assignee: Baird Atomic Inc
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Filing: 1973-08-29
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Granted: 1975-02-18
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Expires: 1993-08-29
Abstract
Abstract A pair of relatively movable objects are aligned to each other in a predetermined relationship by matching images of fixed reticles on the objects to a rotating reticle by convolution of the fixed reticle images with the rotating reticle and generating analog image displacement signals representing the relative positions of the objects for closed loop control of the relative positions of the objects. The energy generated by the convolution of the objects is transduced by radiometric detectors to electrical signals having characteristic frequencies defining the relative positions of the objects. The characteristic frequencies are generated by a frequency phase lock control which provides interrogation of the objects by the reticle scan, the rotating reticle operating as a relative spatial reference which is phaselocked to a fixed frequency generated by a stable oscillator. Doppler frequencies corresponding to image velocities are digitally detected by doppler comparators and converted to doppler phase shift signals corresponding to the relative displacements of the objects. The digital doppler phase shift signals and digital signals corresponding to a desired offset between the objects are accumulated in a tracking register. The accumulated digital signals are converted to analog signals for closed loop control of the relative positions of the objects with respect to each other.
Inventors
- 👤 William Westell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:08
CPC Classifications
G; G03; G03F; G03F9/00; G03F9/70; G03F9/7088; G01; G01S; G01S3/00; G01S3/78; G01S3/782; G01S3/785; G01S3/786
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
145 words
A system for determining the relative displacement between two objects, said system comprising: a. sensor means for imaging a field of view of one object and a field of view of another object at a focal surface and for generating optical image signals related to the relative displacement of said fields of view at said focal surface, said optical image signals being periodic electrical signals having zero crossings; and b. sensor electronic means operatively connected to said sensor means for generating alignment signals related to said optical image signals and the relative displacement of the objects, said sensor electronic means including threshold decision logic means having an established threshold level, said optical image signals applied to said threshold decision logic means, said sensor electronic means generating said alignment signals when said established threshold level is exceeded before each zero crossing of said optical image signals.
Claim 2
Independent Claim
145 words
A system for determining the relative displacement between two objects, said system comprising: a. sensor means for imaging a field of view of one object and a field of view of another object at a focal surface and for generating optical image signals related to the relative displacement of said fields of view at said focal surface, said optical image signals being periodic electrical signals having zero crossings; and b. sensor electronic means operatively connected to said sensor means for generating alignment signals related to said optical image signals and the relative displacement of the objects, said sensor electronic means including threshold decision logic means having an established threshold level, said optical image signals applied to said threshold decision logic means, said sensor electronic means generating said alignment signals when said established threshold level is exceeded before each zero crossing of said optical image signals.
Claim 3
Dependent Claim
87 words
The system as claimed in claim 1 wherein said sensor electronic means includes doppler comparator means and tracking register means, said doppler comparator means operatively connected to said threshold decision logic means, said tracking register means operatively connected to said doppler comparator means, said doppler comparator means generating a difference signal related to the displacement of the representations of said fields of view said difference signal being applied to said tracking register means when said threshold is exceeded before each zero crossing of said optical image signals.
Claim 4
Dependent Claim
40 words
The system as claimed in claim 2 wherein said sensor means includes rotating reticle means communicating with an optical path along which light flux of said fields of view propogate, said rotating reticle means operating as a relative spatial reference.
Claim 5
Dependent Claim
34 words
The system as claimed in claim 3 including clock means operatively connected to said rotating reticle means, said clock means generating clock pulses for synchronizing said rotating reticle means and said sensor electronic means.
Claim 6
Dependent Claim
109 words
The system as claimed in claim 2 wherein said sensor electronic means includes: a. threshold crossing analog to digital converter means operatively connected between said sensor means and said threshold decision logic means for processing said optical image signals, said threshold crossing analog to digital converter means providing a digital AM threshold FM cross-correlation optimum estimation process which eliminates dropouts due to image fluctuations; and b. zero crossing analog to digital converter means operatively connected between said sensor means and said threshold decision logic means for processing said optical image signals, said zero crossing analog to digital converter means optimizing correlation measurements at optical image signals zero crossing times.
Claim 7
Dependent Claim
82 words
The system as claimed in claim 5 wherein said sensor electronic means includes: a. clock means for generating synchronization pulses; b. reference counter means operatively connected to said clock means; and C. register digital to analog converter means operatively connected to said tracking register means; d. said tracking register means read out through said register digital to analog converter means; e. said register digital to analog converter means generating position signals defining relative displacements of the representation of said field of views.
Claim 8
Dependent Claim
53 words
The system as claimed in claim 6 wherein said sensor means includes reticle means and means for rotating said reticle means; and said sensor electronic means includes phase lock servo means for controlling said means for rotating, said reference counter means generating a reference signal which is applied to said phase-lock servo means.
Claim 9
Independent Claim
187 words
A system for aligning a pair of objects, each said object having reticle bars, said system comprising: a. movable platform means on which at least one of the objects is mounted; b. sensor means including rotating reticle means communicating with an optical path along which light flux of images of the reticle bars propogates, said rotating reticle means imaging fields of view of the reticle bars of the objects at a focal surface and for generating an optical image signal functionally related to the displacement of said fields of view in said focal surface, said optical image signal being a periodic electrical signal which is characterized by zero crossings; and c. sensor electronic means operatively connected to said sensor means and said movable platform means, said sensor electronic means generating alignment signals related to said optical image signal, said sensor electronic means including threshold decision logic means having an established threshold level, said alignment signals generated by said sensor electronic means when said threshold level is exceeded before each zero crossing of said optical image signal, said alignment signals related to the relative displacement between the objects.
Claim 10
Independent Claim
187 words
A system for aligning a pair of objects, each said object having reticle bars, said system comprising: a. movable platform means on which at least one of the objects is mounted; b. sensor means including rotating reticle means communicating with an optical path along which light flux of images of the reticle bars propogates, said rotating reticle means imaging fields of view of the reticle bars of the objects at a focal surface and for generating an optical image signal functionally related to the displacement of said fields of view in said focal surface, said optical image signal being a periodic electrical signal which is characterized by zero crossings; and c. sensor electronic means operatively connected to said sensor means and said movable platform means, said sensor electronic means generating alignment signals related to said optical image signal, said sensor electronic means including threshold decision logic means having an established threshold level, said alignment signals generated by said sensor electronic means when said threshold level is exceeded before each zero crossing of said optical image signal, said alignment signals related to the relative displacement between the objects.
Claim 11
Dependent Claim
81 words
The system as claimed in claim 8 wherein said sensor electronic means includes doppler comparator means and tracking register means, said doppler comparator means operatively connected to said threshold decision logic means, said tracking register means operatively connected to said doppler comparator means, said doppler comparator means generating a difference signal related to the relative displacement of the reticles, said difference signal applied to said tracking register when said threshold is exceeded before each zero crossing of said optical image signal.
Claim 12
Dependent Claim
34 words
The system as claimed in claim 9 including clock means operatively connected to said rotating reticle means, said clock means generating clock pulses for synchronizing said rotating reticle means and said sensor electronic means.
Claim 13
Dependent Claim
109 words
The system as claimed in claim 8 wherein said sensor electronic means includes: a. threshold crossing analog to digital converter means operatively connected between said sensor means and said threshold decision logic means for processing said optical image signal, said threshold crossing analog to digital converter means providing a digital AM threshold FM cross-correlation optimum estimation process which eliminates dropouts due to image fluctuations; and b. zero crossing analog to digital converter means operatively connected between said sensor means and said threshold decision logic means for processing said optical image signal, said zero crossing analog to digital converter means optimizing correlation measurements at optical image signal zero crossing times.
Claim 14
Dependent Claim
81 words
The system as claimed in claim 11 wherein said sensor electronic means includes: a. clock means for generating synchronization pulses; b. reference counter means operatively connected to said clock means; and c. register digital to analog converter means operatively connected to said tracking register means; d. said tracking register means read out through said register digital to analog converter means; e. said register digital to analog convertEr means generating position signals defining displacements of the representation of said fields of view.
Claim 15
Dependent Claim
50 words
The system as claimed in claim 12 wherein said sensor means includes drive means for rotating said reticle means and said sensor electronic means includes phase lock servo means for controlling said drive means, said reference counter means generating a reference signal which is applied to said phase-lock servo means.
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) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |