US4082415A
Expired / Lapsed
US
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Holographic lens array and method for making the same
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1976-06-01
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Granted: 1978-04-04
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Expires: 1996-06-01
Abstract
Abstract A novel hologram functioning as a multiple lenslet array of high density in which the lenslets have selected small spacings and relatively long focal lengths is disposed in a holographic data recording system to provide an object beam along a selected axis. Using the holographic lens array, a data hologram may be recorded with improved uniformity between data points, efficiency, hologram illumination, and with minimization of data beam blockage. In preparing the novel hologram, a coherent object beam may be used to define a plurality of sources for simultaneous recording of a plurality of lenslets. The lenslets of a refractive precursor array defined by a commercially available fly's eye lens may be illuminated simultaneously, and selected size, shape, spacing and f- number characteristics for the lenslets may be achieved by concurrent optical transformation of the individual beamlets before recording. The precursor array may advantageously be immersed in a surrounding fluid of controllable refractivity, to substantially increase the effective focal length at the precursor lenses, and enable a substantially larger area of each lenslet to be used.
Inventors
- 👤 Robert Ellison Brooks
- 👤 Donald Charles Winter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:52
CPC Classifications
G; G11; G11C; G11C13/00; G11C13/04; G11C13/042; G02; G02B; G02B5/00; G02B5/32
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
107 words
A novel hologram providing a holographic lens array prepared by the method of projecting coherent light through a refractive fly's eye lens array to provide a number of lens images on a record member along with a reference beam to simultaneously record a number of interference patterns, comprising a record member having a light beam modulating recorded interference pattern including a plurality of like areal and spatially disposed optically transformed representations of the individual lens images having given focal lengths and predetermined spacings defining an array of holographic lenses, the area of each lens is sufficiently large to minimize diffractive effects and provide a substantial signal-to-noise ratio.
Claim 2
Dependent Claim
107 words
A novel hologram providing a holographic lens array prepared by the method of projecting coherent light through a refractive fly's eye lens array to provide a number of lens images on a record member along with a reference beam to simultaneously record a number of interference patterns, comprising a record member having a light beam modulating recorded interference pattern including a plurality of like areal and spatially disposed optically transformed representations of the individual lens images having given focal lengths and predetermined spacings defining an array of holographic lenses, the area of each lens is sufficiently large to minimize diffractive effects and provide a substantial signal-to-noise ratio.
Claim 3
Dependent Claim
32 words
The invention as set forth in claim 1 above, wherein the holographic lenses each provide initially converging light beams when illuminated, and wherein the holographic lenses have relative phase differences between them.
Claim 4
Dependent Claim
37 words
The invention as set forth in claim 2 above, wherein the F- number of the holographic lenses is in excess of approximately f/10 and wherein the center-to-center spacings of the lenses are less than approximately 5 mm.
Claim 5
Dependent Claim
38 words
The invention as set forth in claim 3 above, wherein the F- number of the holographic lenses is in excess of f/20, the lenses are at least partially superposed, the center-to-center spacing is less than approximately 1 mm.
Claim 6
Independent Claim
140 words
The method of making a holographic lens array having lenslets of selectable F- number characteristics and a selectable array disposition from a precursor refractive lens array comprising the steps of: generating at least one coherent light beam; illuminating a precursor refractive lens array having lenses with arbitrary spacings and relatively short focal lengths relative to the desired final characteristics to simultaneously image the at least one light beam in a rear image plane as a plurality of spatially disposed converging beamlets; optically transforming the images presented by the precursor array to selected F- number, size, shape and spacing before the rear image plane; and recording a hologram adjacent but spaced apart from the rear image plane to provide areal and spatially disposed lens image representations which have predetermined spacings and longer focal lengths than the lenses of the precursor array.
Claim 7
Independent Claim
140 words
The method of making a holographic lens array having lenslets of selectable F- number characteristics and a selectable array disposition from a precursor refractive lens array comprising the steps of: generating at least one coherent light beam; illuminating a precursor refractive lens array having lenses with arbitrary spacings and relatively short focal lengths relative to the desired final characteristics to simultaneously image the at least one light beam in a rear image plane as a plurality of spatially disposed converging beamlets; optically transforming the images presented by the precursor array to selected F- number, size, shape and spacing before the rear image plane; and recording a hologram adjacent but spaced apart from the rear image plane to provide areal and spatially disposed lens image representations which have predetermined spacings and longer focal lengths than the lenses of the precursor array.
Claim 8
Dependent Claim
65 words
The method as set forth in claim 5 above, further including the step of concurrently substantially extending the focal length of the converging beamlets from the refractive lens array, thereafter superimposing the images presented by the precursor array, and shaping the superimposed images such that a substantial majority of the light through each lens in the precursor array is utilized in the subsequently recorded hologram.
Claim 9
Dependent Claim
47 words
The method as set forth in claim 6 above, wherein the step of extending the focal length comprises surrounding at least the broad faces of the precursor lens array with a light refractive medium having a refractive index intermediate that of air and the precursor lens array.
Claim 10
Dependent Claim
32 words
The method as set forth in claim 7 above, wherein the step of extending the focal length comprises using a transparent solution containing selectable proportions of solids to vary the refractive index.
Claim 11
Dependent Claim
16 words
The method as set forth in claim 8 above, wherein the solution comprises a sugar-containing solution.
Claim 12
Dependent Claim
18 words
The method as set forth in claim 5 above, wherein the recording partially superposes adjacent lens image representations.
Claim 13
Independent Claim
201 words
The method of preparing, on a record member, a high density holographic lens array having long focal length lenslet equivalents at selected spacings from a precursor array of individual refractive lenses with arbitrary spacings and relatively short focal lengths comprising the steps of: directing an object beam of coherent light along an axis onto the precursor array to provide a plurality of converging beamlets focusing at an array focal plane and beamlets diverging therefrom; focusing the diverging beamlets at an intermediate focal plane spaced from the array focal plane by a selected first focal distance; shaping the focused beamlets to a selected cross sectional beam configuration at an intermediate focal plane; imaging the shaped beam at the intermediate focal plane onto a rear focal plane spaced apart by a selected second focal distance, a substantial majority of the light available in the beamlets being used within the image; illuminating, with the shaped imaging beam, a record member adjacent to but spaced apart from the rear local plane such that an areal representation of each lens is recorded on the record member; and also illuminating the record member with a reference beam coherent with the object beam to form a hologram thereon.
Claim 14
Independent Claim
201 words
The method of preparing, on a record member, a high density holographic lens array having long focal length lenslet equivalents at selected spacings from a precursor array of individual refractive lenses with arbitrary spacings and relatively short focal lengths comprising the steps of: directing an object beam of coherent light along an axis onto the precursor array to provide a plurality of converging beamlets focusing at an array focal plane and beamlets diverging therefrom; focusing the diverging beamlets at an intermediate focal plane spaced from the array focal plane by a selected first focal distance; shaping the focused beamlets to a selected cross sectional beam configuration at an intermediate focal plane; imaging the shaped beam at the intermediate focal plane onto a rear focal plane spaced apart by a selected second focal distance, a substantial majority of the light available in the beamlets being used within the image; illuminating, with the shaped imaging beam, a record member adjacent to but spaced apart from the rear local plane such that an areal representation of each lens is recorded on the record member; and also illuminating the record member with a reference beam coherent with the object beam to form a hologram thereon.
Claim 15
Dependent Claim
59 words
The method as set forth in claim 11 above, wherein the first and second focal distances are selected to determine the effective focal length of the lenses of the holographic lens array, and wherein the f- number of the lenses of the holographic lens array is in excess of f/10 and the center-to-center spacing is less than 5 mm.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-04-03 | 1981-10-03 | 1982-04-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-04-03 | 1985-10-03 | 1986-04-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-04-03 | 1989-10-03 | 1990-04-04 | $7700.00 | Window Closed / Lapsed |