Patent US4471447A successfully refreshed from Google Patents.
US4471447A
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Method for aligning an optical system utilizing focal plane image intensity data
Assignee: Raytheon Co
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Filing: 1981-09-08
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Granted: 1984-09-11
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Expires: 2001-09-08
Abstract
Abstract A complex optical system may be maintained in alignment by means of a technique in which an analytical model of the system is utilized which is assumed to be capable of essentially optimal performance. A physical example of the same system design is then assembled and a plurality of performance characteristics are measured related to the intensity function associated with a point source image on the system's focal plane detector array. A plurality of specific adjustments are then calculated by means of a second order approximation technique which would have the effect of degrading the performance of the analytical model to equal that measured for the physical example, whereupon compensating physical adjustments are made to the physical example to improve its measured performance.
Inventors
- 👤 Samuel G. L. Williams
- 👤 Ning Wu
- 👤 Brent L. Ellerbroek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:50
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/26; G01B11/27; G01B11/272; G02; G02B; G02B17/00; G02B17/02; G02B17/06; G02B17/0626; G02B17/0631; G02B17/0647; G02B17/0663
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
201 words
An improved method for aligning an optical system comprising the steps of: (a) creating an analytical model of a specific optical system design comprising a plurality of individual optical elements having respective optical characteristics and spatial relationships with each other; (b) assembling a complete physical optical system including individual optical elements with respective optical characteristics and spatial relationships having corresponding characteristics and spatial relationships to said analytical optical system model; (c) providing an object source to produce a reference image on the focal plane of the physical optical system; (d) measuring a plurality of predetermined intensity charactristics associated with the focal plane reference image of said physical optical system and producing a first set of representative signals; (e) calculating from said respresentative signals specific adjustments to the spatial relationships between optical elements in said analytical model so as to result in a modified analytical model providing a degraded calculated focal plane image intensity characteristic performance similar to the measured image intensity characteristics of said physical optical system for the same reference image, and (f) making physical adjustments to the corresponding spatial relationships of said physical optical system in response to said specific adjustments to said analytical model calculated in step (e).
Claim 2
Dependent Claim
201 words
An improved method for aligning an optical system comprising the steps of: (a) creating an analytical model of a specific optical system design comprising a plurality of individual optical elements having respective optical characteristics and spatial relationships with each other; (b) assembling a complete physical optical system including individual optical elements with respective optical characteristics and spatial relationships having corresponding characteristics and spatial relationships to said analytical optical system model; (c) providing an object source to produce a reference image on the focal plane of the physical optical system; (d) measuring a plurality of predetermined intensity charactristics associated with the focal plane reference image of said physical optical system and producing a first set of representative signals; (e) calculating from said respresentative signals specific adjustments to the spatial relationships between optical elements in said analytical model so as to result in a modified analytical model providing a degraded calculated focal plane image intensity characteristic performance similar to the measured image intensity characteristics of said physical optical system for the same reference image, and (f) making physical adjustments to the corresponding spatial relationships of said physical optical system in response to said specific adjustments to said analytical model calculated in step (e).
Claim 3
Dependent Claim
77 words
The method of claim 1 further including the steps of: (g) making a second series of measurements of said plurality of predetermined characteristics associated with the optical performance of said physical system and producing a second set of representative signals, and (h) comparing the first set of representative signals with the second set and if the difference is beyond a predetermined limit, then repeating the steps of (e) and (f) with the second set of representative signals.
Claim 4
Dependent Claim
83 words
The method of claim 1 wherein said analytical model is a software model comprising: machine readable data specifying said optical characteristics and spatial relationships and further those spatial relationships which are adjustable and the ranges of adjustment associated respectively therewith, and a series of computer program instructions for causing a digital computer to calculate data representative of the focal plan image intensity characteristics of an optical system wherein at least some of the adjustable spatial relationships have been adjusted by a predetermined amount.
Claim 5
Dependent Claim
41 words
The method of claim 1 wherein a set of predetermined equations are used in calculating the specific adjustments to said spatial relationship of step (e), said set of equations expressing said intensity characteristics as second order functions of said spatial relationships.
Claim 6
Dependent Claim
15 words
The method of claim 1 wherein said adjustments to said physical system are made manually.
Claim 7
Dependent Claim
15 words
The method of claim 1 wherein said adjustments to said physical system are made automatically.
Claim 8
Independent Claim
185 words
A method of minimizing aberrations associated with the performance of a complex optical system by making compensating adjustment to the spatial and rotational relationships between different optical elements in said system, said method comprising the steps of: measuring the performance of said optical system as a function of the intensity of the image of a point source at different locations at the focal plane of said system compared to the corresponding intensity measurements of a predetermined perfectly aligned optical system free of any significant aberrations; making two sets of said performance measurements, one set prior to and one set subsequent to a physical adjustment to at least one of said spatial and rotational relationships; calculating an initial estimate of aberrations form a linear function "second difference" equation expressing the difference in focal plane image intensity prior to and subsequent to said physical adjustment, and producing representative signals of said initial estimates; calculating from the representative signals by a second order approximation algorithm the appropriate compensating adjustments to minimize the aberrations in said optical system, and making said spatial and rotational adjustments to said optical elements.
Claim 9
Independent Claim
185 words
A method of minimizing aberrations associated with the performance of a complex optical system by making compensating adjustment to the spatial and rotational relationships between different optical elements in said system, said method comprising the steps of: measuring the performance of said optical system as a function of the intensity of the image of a point source at different locations at the focal plane of said system compared to the corresponding intensity measurements of a predetermined perfectly aligned optical system free of any significant aberrations; making two sets of said performance measurements, one set prior to and one set subsequent to a physical adjustment to at least one of said spatial and rotational relationships; calculating an initial estimate of aberrations form a linear function "second difference" equation expressing the difference in focal plane image intensity prior to and subsequent to said physical adjustment, and producing representative signals of said initial estimates; calculating from the representative signals by a second order approximation algorithm the appropriate compensating adjustments to minimize the aberrations in said optical system, and making said spatial and rotational adjustments to said optical elements.
Claim 10
Dependent Claim
48 words
The method of claim 7 wherein the optical system includes a detector for converting light into electrical signals at its predetermined focal plane and said step of measuring the intensity of said image point is performed only at the focal plane of the optical system by said detector.
Claim 11
Dependent Claim
42 words
The method of claim 7 wherein said point source is a predetermined celestial object within the field of view of said optical system and wherein said compensation is being performed while other celestial objects are being examined within said field of view.
Claim 12
Dependent Claim
30 words
The method of claim 9 wherein a single array of operational detectors makes said intensity measurements relating both to said point source celestial object and to said other celestial objects.
Claim 13
Dependent Claim
25 words
The method of claim 7 wherein said perfectly aligned optical system is a software model comprising machine readable data calculated from said physical optical system.
Claim 14
Dependent Claim
19 words
The method of claim 7 wherein said performance measurements relate to wavefront and image intensity from a point source.
Claim 15
Dependent Claim
211 words
An improved optical system having a realignment capability comprising: an optical system having a number of individual optical units with complementary optical characteristics and spatial relationships to each other positioned on an optical axis extending from an object to an image side, a plurality of optical units being movably mounted relative to the optical axis and having an interactive effect on the image transmitting ability of image side optical units; means for moving the movably mounted optical units to change their respective spatial positions; means for providing signals indicative of an analytical optical model of an optimized optical system capable of providing the predetermined optical performance desired by the optical system; means for measuring a reference image at the focal plane to provide measurement signals representative of the intensity distribution of a point source image; means for comparing the measurement signals with the signals indicative of the analytical model by a second order approximation to generate alignment signals necessary to conform the optical performance of the analytical model to that of the measured optical system, and means for applying the adjustment signals to the means for moving the optical units to realign the spatial position of the optical units for conformance with the predetermined optical performance of the analytical optical model.
Claim 16
Dependent Claim
211 words
An improved optical system having a realignment capability comprising: an optical system having a number of individual optical units with complementary optical characteristics and spatial relationships to each other positioned on an optical axis extending from an object to an image side, a plurality of optical units being movably mounted relative to the optical axis and having an interactive effect on the image transmitting ability of image side optical units; means for moving the movably mounted optical units to change their respective spatial positions; means for providing signals indicative of an analytical optical model of an optimized optical system capable of providing the predetermined optical performance desired by the optical system; means for measuring a reference image at the focal plane to provide measurement signals representative of the intensity distribution of a point source image; means for comparing the measurement signals with the signals indicative of the analytical model by a second order approximation to generate alignment signals necessary to conform the optical performance of the analytical model to that of the measured optical system, and means for applying the adjustment signals to the means for moving the optical units to realign the spatial position of the optical units for conformance with the predetermined optical performance of the analytical optical model.
Claim 17
Dependent Claim
32 words
The invention of claim 13 wherein the means for measuring a reference image consists within the optical system of only a detector array positioned at the focal plane of the optical system.
Claim 18
Dependent Claim
42 words
The invention of claim 14 wherein the means for moving the optical units further includes means for focusing the optical system and the means for measuring a reference image performs at least two focal plane intensity measurements at two separate focus positions.
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) | 1987-09-11 | 1988-03-12 | 1988-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-09-11 | 1992-03-12 | 1992-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-09-11 | 1996-03-12 | 1996-09-11 | $7700.00 | Window Closed / Lapsed |