US4445759A
Expired / Lapsed
US
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Integrated Fresnel lens and its production process
Assignee: Commissariat à l'Énergie Atomique et Aux Énergies Alternatives
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Filing: 1981-10-05
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Granted: 1984-05-01
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Expires: 2001-10-05
Abstract
Abstract Fresnel lens for integrated optics, wherein it comprises a light guide of effective index n eff incorporating a guiding layer and a number N of regions of length L(r) measured in the direction of the lens axis as a function of the distance r from the lens axis and disposed in the direction perpendicular to the lens axis, while having a refractive index such that to the right of these regions the effective index of the light guide has a value n' eff which differs from n eff in such a way that a light wave propagated to the right of these regions is given a phase displacement Δφ due to the effective index difference n' eff -n eff and making it possible to obtain constructive light interferences at the chosen image point. The invention also relates to a process for producing a Fresnel lens in which the regions are produced by ion implantation.
Inventors
- 👤 Serge Valette
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:20
CPC Classifications
G; G02; G02B; G02B3/00; G02B3/02; G02B3/08; G02B6/00; G02B6/10; G02B6/12; G02B6/122; G02B6/124; G02B6/1245
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
139 words
A Fresnel lens for integrated optics, wherein it comprises a light guide of effective index n eff achieved in a substrate and incorporating a guiding layer and a number N of regions of length L(r) measured in the direction of the lens axis as a function of the distance r from the lens axis and disposed in the direction perpendicular to the lens axis, while having a refractive index such that to the right of these regions the effective index of the light guide has a value n' eff which differs from n eff in such a way that a light wave propagated to the right of these regions is given a phase displacement Δφ due to the effective index difference n' eff -n eff and making it possible to obtain constructive light interferences at the chosen image point.
Claim 2
Dependent Claim
139 words
A Fresnel lens for integrated optics, wherein it comprises a light guide of effective index n eff achieved in a substrate and incorporating a guiding layer and a number N of regions of length L(r) measured in the direction of the lens axis as a function of the distance r from the lens axis and disposed in the direction perpendicular to the lens axis, while having a refractive index such that to the right of these regions the effective index of the light guide has a value n' eff which differs from n eff in such a way that a light wave propagated to the right of these regions is given a phase displacement Δφ due to the effective index difference n' eff -n eff and making it possible to obtain constructive light interferences at the chosen image point.
Claim 3
Dependent Claim
16 words
A Fresnel lens according to claim 1, wherein the light guide is made from lithium niobate.
Claim 4
Dependent Claim
17 words
A Fresnel lens according to claims 1 or 2, wherein the regions have a concave front face.
Claim 5
Dependent Claim
72 words
A Fresnel lens according to claim 3, wherein the regions N have a length L(r) which is dependent on the distance r from the axis of the lens with: ##EQU8## in which p and p' represents the distances between the object and image points, λ 0 the wavelength in the vacuum of the light wave used, L 0 the maximum length and m a positive integer varying successively from 1 to N.
Claim 6
Dependent Claim
15 words
A Fresnel lens according to claim 1, wherein the regions have a convex rear face.
Claim 7
Dependent Claim
71 words
A Fresnel lens according to claim 5, wherein the regions N have a length L(r) dependent on the distance r from the axis of the lens with: ##EQU9## in which p and p' represent the distances between the object and image points, λ 0 the wavelength λ in the vacuum of the light wave used, L 0 the maximum length and m a positive integer varying successively from 1 to N.
Claim 8
Dependent Claim
21 words
A Fresnel lens according to claim 1, wherein the length L(r) of the said regions is satisfactory in an approximate manner.
Claim 9
Dependent Claim
14 words
A Fresnel lens according to claim 7, wherein the approximation is at two levels.
Claim 10
Dependent Claim
24 words
A process for the production of a Fresnel lens according to claim 1, wherein the regions are produced by means of an ion implantation.
Claim 11
Dependent Claim
14 words
A production process according to claim 9, wherein the implanted ions are helium ions.
Claim 12
Dependent Claim
26 words
A production process according to claim 10, wherein the number of ions implanted per square centimeter of substrate is between 10 15 and 10 16 .
Claim 13
Dependent Claim
14 words
A production process according to claim 9, wherein the implanted ions are boron ions.
Claim 14
Dependent Claim
23 words
A production process according to claim 9, wherein the ions are implanted through a mask deposited on the surface of the light guide.
Claim 15
Dependent Claim
13 words
A production process according to claim 9, wherein the regions are chemically etched.
Claim 16
Dependent Claim
24 words
A production process according to claim 14, wherein, in the case of a lithium niobate substrate, chemical etching takes place with dilute hydrofluoric acid.
References Cited (Backward Citations)
US4367916A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-05-01 | 1987-10-31 | 1988-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-01 | 1991-10-31 | 1992-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-01 | 1995-10-31 | 1996-05-01 | $7700.00 | Window Closed / Lapsed |