US3837725A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Systems for constructing small fresnel holograms
Assignee: Thales SA
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Filing: 1972-06-16
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Granted: 1974-09-24
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Expires: 1992-06-16
Abstract
Abstract The present invention relates to the construction of Fresnel holograms having an area smaller than the area of the non-uniform transparency object utilised to construct them. The invention relates to a construction system wherein the illumination of the object is effected through the medium of an optical concentrating system converting a parallel beam, into a set of elementary parallel beams intersecting in the exposure window. The invention can be applied to the high-density storage of optical data.
Inventors
- 👤 C Bricot
- 👤 Merer J Le
- 👤 C Puech
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:01
CPC Classifications
G; G03; G03H; G03H1/00; G03H1/32
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
194 words
An optical system for constructing Fresnel holograms from an object of non-uniform transparency carrying optical data, said system comprising: a source of coherent radiation emitting a collimated object beam and a reference beam; an object window having an aperture for positioning said object in the path of said collimated object beam; and an exposure window having an aperture Arranged for receiving a radiation detector, and positioned for receiving the radiant energy contained in said reference beam and a fraction of the radiant energy emerging from the aperture of said object window; said system further comprising: optical concentrating means arranged between said source of coherent radiation and the aperture of said object window for converting said collimated object beam into a set of collimated elementary beams intersecting one another in the aperture of said exposure window; the aperture of said object window having an area larger than the area of the aperture of said exposure window, and being fully illuminated by said set of collimated elementary beams; the wavefronts of said collimated elementary beams remaining substantially plane between said optical concentrating means and the aperture of said exposure window in the absence of said object.
Claim 2
Dependent Claim
194 words
An optical system for constructing Fresnel holograms from an object of non-uniform transparency carrying optical data, said system comprising: a source of coherent radiation emitting a collimated object beam and a reference beam; an object window having an aperture for positioning said object in the path of said collimated object beam; and an exposure window having an aperture Arranged for receiving a radiation detector, and positioned for receiving the radiant energy contained in said reference beam and a fraction of the radiant energy emerging from the aperture of said object window; said system further comprising: optical concentrating means arranged between said source of coherent radiation and the aperture of said object window for converting said collimated object beam into a set of collimated elementary beams intersecting one another in the aperture of said exposure window; the aperture of said object window having an area larger than the area of the aperture of said exposure window, and being fully illuminated by said set of collimated elementary beams; the wavefronts of said collimated elementary beams remaining substantially plane between said optical concentrating means and the aperture of said exposure window in the absence of said object.
Claim 3
Dependent Claim
19 words
An optical system as claimed in claim 1, wherein said optical concentrating means comprise at least one diffraction grating.
Claim 4
Dependent Claim
31 words
An optical system as claimed in claim 2, wherein the profile of the grooves in said grating is selected in order to uniformly distribute the radiant energy between said elementary beams.
Claim 5
Dependent Claim
34 words
An optical system as claimed in claim 2, wherein said grating is associated with a second similar diffraction grating; the grooves of said second grating being perpendicular to the grooves of said one grating.
Claim 6
Dependent Claim
20 words
An optical system as claimed in claim 1, wherein said optical concentrating means comprise more than two superimposed diffraction gratings.
Claim 7
Dependent Claim
61 words
An optical system as claimed in claim 1, wherein said optical concentrating means comprise: a set of adjacent lenses receiving said object beam and having a common focal plane, and a supplementary lens having one of its focal planes coincident with said focal plane; the aperture of said exposure windows being located in the other focal plane of said supplementary lens.
Claim 8
Dependent Claim
17 words
An optical system as claimed in claim 6, wherein said lenses are made of a refractive material.
Claim 9
Dependent Claim
14 words
An optical system as claimed in claim 6, wherein said lenses are holographic lenses.
Claim 10
Dependent Claim
30 words
An optical system as claimed in claim 6, wherein the lenses constituting said set have a total area substantially equal to the area of the aperture of said exposure window.
Claim 11
Dependent Claim
29 words
An optical system as claimed in claim 6, wherein the lenses constituting said set have an total area smaller than the area of the aperture of said exposure window.
Claim 12
Dependent Claim
26 words
An optical system as claimed in claim 6, wherein the lenses constituting said set are formed by the superimposition of two orthogonal networks of cylindrical lenses.
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) | 1977-09-23 | 1978-03-25 | 1978-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-23 | 1982-03-25 | 1982-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-23 | 1986-03-25 | 1986-09-24 | $7700.00 | Window Closed / Lapsed |