Diffraction bifocal with adjusted chromaticity
OwnerAllen L. Coheninventor
Life of this patent
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Abstract
A diffraction bifocal lens or lens system, comprising two profiled surfaces or interfaces or a linear combination thereof, wherein one profile provides for the bifocality of the lens and the other profile compensates for chromatic aberration. These lenses or lens systems exhibit two focal points, one which exhibits positive chromatic aberration and the other which exhibits negative chromatic aberration.
Claims24
An optical lens comprising;
- (a) a first profiled surface or interface, for diffracting light to two adjacent non negative focal orders m and (m+1), m=0, 1, 2,. . . , comprising a plurality of annular concentric zones spaced according to the formula
- r.sub.k =.sqroot.(k d.lambda.) k=1, 2, 3,
- where .lambda. is the design wavelength, d is the primary focal length of the surface or interface. k is a zone, and r.sub.k is the zone radius, and
- (b) a second profiled surface or interface, for diffracting light to a negative focal order -M, M=1, 2, 3, . . . , comprising a plurality of annular concentric zones spaced according to the formula
- R.sub.k =.sqroot.(kD.lambda.) k=1, 2, 3,
- where D is the primary focal length of the surface or interface, and R.sub.k is the zone radius,
- said surfaces aligned such that their optical axes are coincident, and such that (m+1)/d >M/D >m/d thereby providing for positive chromatic aberration to be associated with a first focal point and negative chromatic aberration to be associated with a second focal point.
An optical lens comprising;
- (a) a first profiled surface or interface, for diffracting light to two adjacent non positive focal orders -m and -(m+1), m=0,1,2, . . . , comprising a plurality of annular concentric zones spaced according to the formula
- r.sub.k =.sqroot.(kd .lambda.)k=1, 2, 3, . . . ,
- where .lambda. is the design wavelength, d is the primary focal length of the surface or interface, k is a zone, and r.sub.k is the zone radius, and
- (b) a second profiled surface or interface, for diffracting light to a positive focal order +M, M=1, 2, 3, . . . , comprising a plurality of annular concentric zones spaced according to the formula
- R.sub.k =.sqroot.(kD.lambda.)k=1, 2, 3, . . . ,
- where D is the primary focal length of the surface or interface, and R.sub.k is the zone radius,
- said surfaces aligned such that their optical axes are coincident, and such that (m+1)/d>M/D>m/d thereby providing for positive chromatic aberration to be associated with a first focal point and negative chromatic aberration to be associated with a second focal point.
An optical lens comprising one profiled surface or interface, for diffracting light to two distinct focal powers, comprising a plurality of annular concentric zones, and providing for positive chromatic aberration to be associated with a first focal point and negative chromatic aberration to be associated with a second focal point such that the amount of negative chromatic aberration exceeds the amount of positive chromatic aberration.
An optical lens comprising one profiled surface or interface, for diffracting light to two distinct focal powers, comprising a plurality of annular concentric zones, and providing for positive chromatic aberration to be associated with a first focal point and negative chromatic aberration to be associated with a second focal point such that the amount of positive chromatic aberration exceeds the amount of negative chromatic aberration.
Dependencies are inferred from the claim text.