US5589982A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polychromatic diffractive lens
Assignee: Corning Rochester Photonics Corp
•
Filing: 1994-06-03
•
Granted: 1996-12-31
•
Expires: 2014-06-03
Abstract
Abstract A polychromatic diffractive lens is usable with broadband or multi-spectral illumination to bring a plurality of spectral components of the illumination to a common focus in space. The lens has a Fresnel zone structure of zones and a profile which provides a phase jump delay at each zone boundary to the illumination of at least one of the spectral components which is greater than one period (wave) of that wavelength, and more particularly, a multiple of 2πp, where p is an integer greater than or equal to two. The parameter p and the width of the zones are selected so that the spectral components are directed, and if desired directed so as to be brought to the common focus with high diffraction efficiency in distinct diffractive orders, the lens thereby being a multi-order diffractive (MOD) lens. Applications for MOD lenses are in color (RGB) displays, color laser printers, which printers may utilize one MOD lens to image laser beams in red, blue and green wavelengths (multi-spectral illumination) to the same focal spot for forming color images as the beams scan an image forming element, such as a xerographic receptor.
Inventors
- 👤 Dean Faklis
- 👤 G. Michael Morris
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 21:56
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/18; G02B5/1876
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
70 words
A diffractive lens for directing a plurality of different wavelengths of radiation to a single focus which comprises a diffractive structure having a plurality of zones which define zone boundaries at which light incident on the structure experiences an optical phase shift, and which diffract light of each of said wavelengths in a different diffractive order, m, such that m≧1, to said focus, thereby providing a plural order diffractive singlet.
Claim 2
Dependent Claim
70 words
A diffractive lens for directing a plurality of different wavelengths of radiation to a single focus which comprises a diffractive structure having a plurality of zones which define zone boundaries at which light incident on the structure experiences an optical phase shift, and which diffract light of each of said wavelengths in a different diffractive order, m, such that m≧1, to said focus, thereby providing a plural order diffractive singlet.
Claim 3
Dependent Claim
33 words
The lens according to claim 1 wherein said zone boundaries present the same optical phase shift to light of one of said plurality of wavelengths, which phase shift is greater than one wave.
Claim 4
Dependent Claim
69 words
The lens according to claim 2, wherein said zones are radially spaced at radii, r j and said radii are obtained by solving the equation φ(r j )=2πp j where φ(r) represents the phase function for the wavefront emerging from the diffractive lens, and p represents the number of 2π phase jumps at the zone boundaries for one of the plurality of wavelengths where p is an integer >1.
Claim 5
Dependent Claim
86 words
The lens according to claim 2 wherein said element defines a lens having a focal length and the zone boundaries are numbered in order of their radial distance from center of the lens, said zones defining different optical path lengths to the focus which are equal to the sum of the focal length of the lens and the product of the number of the zone boundary, the phase shift presented by the boundary in waves and the wavelength of said one of said plurality of wavelengths.
Claim 6
Dependent Claim
26 words
The lens according to claim 4 which defines an optical axis along the center of the lens, and the focal length is along said optical axis.
Claim 7
Dependent Claim
18 words
The lens according to claim 4 wherein said annular zones are circular and centered about said optical axis.
Claim 8
Dependent Claim
14 words
The lens according to claim 1 wherein said structure has a surface relief profile.
Claim 9
Dependent Claim
15 words
The lens according to claim 7 wherein said surface relief profile is a blaze profile.
Claim 10
Dependent Claim
12 words
The lens according to claim 1 wherein said lens has optical power.
Claim 11
Dependent Claim
17 words
The lens according to claim 7 wherein said surface relief profile is on an optically transmissive substrate.
Claim 12
Dependent Claim
25 words
The lens according to claim 10 wherein said substrate has opposite surfaces on one of which said profile is disposed and the other is planar.
Claim 13
Dependent Claim
108 words
The lens according to claim 1 wherein the phase shift at the boundaries is a phase jump φ(r j )=2πp where j is the an integer indexing to border of the boundaries, r j is the locations of the boundaries in number order, j=1 being the zone boundary location closest to the center of the zones, and p is an integer, equal or greater than two, and λ 0 is one of said plurality of wavelengths and λ i are others of said plurality of wavelengths where ##EQU14## where m is the order of diffraction of each of said others of said plurality of wavelengths to said focus.
Claim 14
Dependent Claim
34 words
The lens according to claim 12 wherein said lens has a focal length F 0 to said focus and said zone boundaries locations r j are determined by the following equation r.sup.2.sub.j =2jpλ.sub.0 F.sub.0
Claim 15
Dependent Claim
20 words
The lens according to claim 13 wherein said plurality of wavelengths is two and said element is an achromat singlet.
Claim 16
Dependent Claim
20 words
The lens according to claim 13 wherein said plurality of wavelengths are three and said lens is an apochromat singlet.
Claim 17
Dependent Claim
24 words
The lens according to claim 15 wherein said wavelengths are wavelengths which appear as red, blue and green colors to the human eye, respectively.
Claim 18
Dependent Claim
37 words
The lens according to claim 1 wherein said lens focuses a multiplicity of wavelengths which constitute said plurality at said single focus, each with a different diffractive order and said lens is a multi-order diffractive (MOD) lens.
Claim 19
Dependent Claim
28 words
The lens according to claim 17 wherein one of said multiplicity of wavelengths is a wavelength of about the middle of a band including said multiplicity of wavelengths.
Claim 20
Dependent Claim
17 words
The lens according to claim 1 wherein said plurality of wavelengths are within broadband or multi-spectral illumination.
Claim 21
Dependent Claim
15 words
The lens according to claim 7 wherein said surface relief profile defines a reflective surface.
Claim 22
Dependent Claim
17 words
The lens according to claim 4 wherein said zones are elliptical and centered about said optical axis.
References Cited (Backward Citations)
US4637697A
Cited
US5144483A
Cited
US4936665A
Cited
US5013133A
Cited
US4936666A
Cited
US5237451A
Cited
WO1991012551A1
Cited
US5442480A
Cited
US5178636A
Cited
US5071207A
Cited
US5257132A
Cited
US5153778A
Cited
US5299797A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-12-31 | 2000-07-01 | 2000-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-12-31 | 2004-07-01 | 2004-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-12-31 | 2008-07-01 | 2008-12-31 | $7700.00 | Window Closed / Lapsed |