Diffractive multi-focal lens
First Claim
Patent Images
1. A multi-focal diffractive lens having a diffractive surface and a plurality of diffractive orders, the surface having an optical height, ho, relative to a bese reference surface which is a periodic function, each period of which is given by:
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space="preserve" listing-type="equation">H·
exp{ (u-u.sub.0)/W.sub.1 !.sup.m1 } for u≦
u.sub.0 ;
and
space="preserve" listing-type="equation">H·
exp{ (u-u.sub.0)/W.sub.2 !.sup.m2 } for u≧
u.sub.0,wherein u0 =2 π
W1 /(W1 +W2), wherein H, W1, W2, m1 and m2 are preselected constants, wherein W1 may be the same as or different from W2 and m1 may be the same as or different from m2, wherein u is a function of r namely u(r) and, wherein the imaging efficiency of each of the diffractive order is not less than twenty percent.
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Abstract
A tri-focal diffractive lens defining three foci, for viewing a band of light having a representative wavelength of λ, including a diffractive surface having a number of optical heights, ho, wherein the difference between the highest and the lowest optical heights is, modulo λ, substantially different from λ/2, wherein each of the foci receives at least 20% of light incident on the lens.
227 Citations
40 Claims
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1. A multi-focal diffractive lens having a diffractive surface and a plurality of diffractive orders, the surface having an optical height, ho, relative to a bese reference surface which is a periodic function, each period of which is given by:
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space="preserve" listing-type="equation">H·
exp{ (u-u.sub.0)/W.sub.1 !.sup.m1 } for u≦
u.sub.0 ;and
space="preserve" listing-type="equation">H·
exp{ (u-u.sub.0)/W.sub.2 !.sup.m2 } for u≧
u.sub.0,wherein u0 =2 π
W1 /(W1 +W2), wherein H, W1, W2, m1 and m2 are preselected constants, wherein W1 may be the same as or different from W2 and m1 may be the same as or different from m2, wherein u is a function of r namely u(r) and, wherein the imaging efficiency of each of the diffractive order is not less than twenty percent. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A multi-focal diffractive lens comprising a diffractive surface, having a surface topography including local minima and maxima, operative to focus light in accordance with a plurality of dominant diffraction orders defining a plurality of respective foci,
wherein the surface topography of the diffractive surface has no discontinuities in the first derivative; -
wherein the imaging efficiency of each of the dominant orders is not less than twenty percent, and wherein the radius of curvature of the diffractive surface, at any given point on the surface, is equal to at least twice the difference in topographical height between the local minimum nearest to the given point and the local maximum nearest to the given point. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. A contact lens comprising:
a first portion and a second portion each having two surfaces and an edge, wherein at least one surface of one of the portions comprises a diffractive surface wherein the diffractive surface faces a surface of the second portion, wherein the two portions are sealed to form a sandwich structure having a sealed third interior portion which is filled with a liquid and having the diffractive surfaces interior to the sandwich and wherein one of outer surfaces of the sandwich structure is adapted to contact the cornea of a user. - View Dependent Claims (35)
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36. A composite contact lens comprising:
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a first portion and a second portion forming a sandwich structure; said first portion having at least one optical element in relief thereon; said second portion having generally smooth interior and exterior surfaces;
wherein said interior surface faces said optical element;
wherein the top of the relief of the optical element touches the interior surface thereby spacing the two portions and forming a well defined optical structure and wherein the optical structure between the two portions is filled with a liquid. - View Dependent Claims (37, 38)
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39. A composite contact lens comprising:
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a first portion and a second portion forming a sandwich structure; said first portion having at least one optical element in relief thereon; said second portion having at least one smooth surface facing said optical element;
wherein the distance from a point on said facing surface, opposite the base of the relief of said optical element, is substantially equal to the height of the top of the relief;wherein the sandwich structure between the first portion and second portion is filled with a liquid. - View Dependent Claims (40)
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Specification