Patent US2210886A successfully refreshed from Google Patents.
US3728006A
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Holographic schlieren method
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1971-10-20
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Granted: 1973-04-17
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Expires: 1991-10-20
Abstract
Abstract A double exposed hologram is reconstructed by the schlieren method. The hologram of a disturbed and undisturbed scene is twice exposed so that the reference beam forms a different angle with the recording material for each exposure. The recording material has a non-linear characteristic so that intermodulation products of the fringes are generated. The hologram is reconstructed with a reconstruction reference beam. All but a selected diffraction order are eliminated and the selected order is viewed with a knife edge to make visible the phase change of the scene recorded. The reconstruction reference beam must be substantially free of aberrations; otherwise there are no such restrictions on the recording optical elements.
Inventors
- 👤 R Brooks
- 👤 L Heflinger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 21:45
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/41; G01N21/45; G01N21/453
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
201 words
A method of recording and reconstructing a hologram of a scene by the schlieren method on a non-linear recording material, which comprises the steps of: a. generating a monochromatic light beam; b. splitting said light beam into a reference beam and a scene beam; c. casting the reference beam on the recording material at a first predetermined angle; d. casting the scene beam upon a scene to be recorded in a first state and then onto the recording material to record a first hologram; e. subsequently casting the reference beam at a second predetermined angle at the recording material; f. casting the scene beam on the scene in a second state and then onto the same recording material to record a second hologram, the scene in its first and second state being disturbed in one state with respect to the other; g. reconstructing the thus obtained double-exposure hologram by illuminating the hologram with a reconstruction reference beam to obtain a moire pattern corresponding to the phase difFerence between the two recorded wave fronts; and h. viewing a selected one of the resulting diffraction orders of the moire pattern by a knife edge, thereby to view the scene by the schlieren method.
Claim 2
Independent Claim
201 words
A method of recording and reconstructing a hologram of a scene by the schlieren method on a non-linear recording material, which comprises the steps of: a. generating a monochromatic light beam; b. splitting said light beam into a reference beam and a scene beam; c. casting the reference beam on the recording material at a first predetermined angle; d. casting the scene beam upon a scene to be recorded in a first state and then onto the recording material to record a first hologram; e. subsequently casting the reference beam at a second predetermined angle at the recording material; f. casting the scene beam on the scene in a second state and then onto the same recording material to record a second hologram, the scene in its first and second state being disturbed in one state with respect to the other; g. reconstructing the thus obtained double-exposure hologram by illuminating the hologram with a reconstruction reference beam to obtain a moire pattern corresponding to the phase difFerence between the two recorded wave fronts; and h. viewing a selected one of the resulting diffraction orders of the moire pattern by a knife edge, thereby to view the scene by the schlieren method.
Claim 3
Dependent Claim
16 words
A method as defined in claim 1 wherein the scene beam is passed through the scene.
Claim 4
Dependent Claim
16 words
A method as defined in claim 1 wherein the scene beam is reflected from the scene.
Claim 5
Dependent Claim
18 words
A method as defined in claim 3 wherein an image of the scene is focused on the hologram.
Claim 6
Dependent Claim
28 words
A method as defined in claim 1 wherein the angle of the reconstruction reference beam with the recording material is different from said first and second predetermined angles.
Claim 7
Dependent Claim
31 words
A method as defined in claim 1 wherein the reconstruction reference beam is a converging bean converging in a predetermined point in the vicinity of which the knife edge is positioned.
Claim 8
Dependent Claim
22 words
A method as defined in claim 1 wherein each of said reference beams is a converging bean converging in a predetermined point.
Claim 9
Dependent Claim
17 words
A method as defined in claim 1 wherein the reconstruction reference beam is substantially free of aberrations.
Claim 10
Dependent Claim
20 words
A method as defined in claim 1 wherein the unwanted diffracted orders of the reconstruction reference beam are blocked off.
Claim 11
Dependent Claim
39 words
A method as defined in claim 1 wherein a knife edge is positioned near the focal point of one of the diffracted orders which permits viewing of the phase changes of the scene recorded on the double exposure hologram.
References Cited (Backward Citations)
US3627426A
Cited
US3601466A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-16 | 1976-10-16 | 1977-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-16 | 1980-10-16 | 1981-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-16 | 1984-10-16 | 1985-04-17 | $7700.00 | Window Closed / Lapsed |