Aspheric lens surface

Claim 2

An aspheric ophthalmic lens for providing desired lens characteristics at substantially all viewing field angles from the optical axis out to about 30* relative to the optical axis, said lens having a front surface and a rear prescriptive surface wherein the front surface of said lens has an aspheric crosssectional curvature defined by the equation x a/(by2 + 1) + cy2 + dy4 - a wherein: x the distance from the front surface vertex of the lens in a direction parallel to the optical axis of the lens; y the perpendicular distance from the optical axis at any point x; and a, b, c and d are coefficients selected to provide the following lens characteristics: a. a substantially correct axial vertex power; b. a substantially zero tangential focus error at a relatively large field angle relative to the optical axis; c. tangential and sagittal focus errors which are approximately equal and opposite at an intermediate field angle relative to the optical axis; and d. substantially minimized zonal aberrations.

Claim 3

An ophthalmic lens as recited in claim 1 wherein the coefficients a, b, c and d are selected to provide said lens with: a. a substantially zero tangential focus error at a field angle of approximately 30* relative to the optical axis; and b. tangential and sagittal focus errors which are approximately equal and opposite at a field angle of approximately 20* relative to the optical axis.

Claim 4

A series of aspheric ophthalmic lenses for providing desired lens characteristics at substantially all viewing field angles from the optical axis out to about 30* relative to the optical axis wherein each of the lenses included within said series has a front surface and a rear prescriptive surface, and wherein the front surface of each of the lenses within said series has an aspheric cross-sectional curvature defined by the equation x a/(by2 + 1) + cy2 + dy4 - a wherein x the distance from the front surface vertex of the lens in a direction parallel to the optical axis of the lens; y the perpendicular distance from the optical axis at any point x; and a, b, c and d are coefficients selected to provide the following lens characterisTics: a. a substantially correct axial vertex power; b. a substantially zero tangential focus error at a relative large field angle relative to the optical axis; c. tangential and sagittal focus errors which are approximately equal and opposite at an intermediate field angle relative to the optical axis; and d. substantially minimized zonal aberrations.

Claim 5

A series of aspheric ophthalmic lenses for providing desired lens characteristics at substantially all viewing field angles from the optical axis out to about 30* relative to the optical axis wherein each of the lenses included within said series has a front surface and a rear prescriptive surface, and wherein the front surface of each of the lenses within said series has an aspheric cross-sectional curvature defined by the equation x a/(by2 + 1) + cy2 + dy4 - a wherein x the distance from the front surface vertex of the lens in a direction parallel to the optical axis of the lens; y the perpendicular distance from the optical axis at any point x; and a, b, c and d are coefficients selected to provide the following lens characterisTics: a. a substantially correct axial vertex power; b. a substantially zero tangential focus error at a relative large field angle relative to the optical axis; c. tangential and sagittal focus errors which are approximately equal and opposite at an intermediate field angle relative to the optical axis; and d. substantially minimized zonal aberrations.

Claim 6

An ophthalmic lens series as recited in claim 3 wherein the coefficients a, b, c and d are selected to provide: a. a substantially zero tangential focus error at a field angle of approximately 30* relative to the optical axis; and b. tangential and sagittal focus errors which are approximately equal and opposite at a field angle of approximately 20* relative to the optical axis.

Claim 7

An ophthalmic lens series as recited in claim 3 wherein said series of lenses comprises lenses having vertex powers from between about +7.75 diopters to about +18 diopters.

Claim 8

A series of aspheric ophthalmic lens surfaces for use with a plurality of lenses having vertex powers extending from about +7.75 diopters to about +18 diopters, each of said plurality of lenses being provided with one of said series of aspheric surfaces on the front surface thereof, wherein said series of aspheric surfaces extends from a base curve of +10.43 diopters to +17.43 diopters and wherein each of the aspheric surfaces in said series has a cross-sectional curvature defined by the equation x a/(by2 + 1) + cy2 + dy4 - a wherein x the distance from the front surface vertex of the lens in a direction parallel to the optical axis of the lens; y the perpendicular distance from the optical axis at any point x; and the coefficients a, b, c and d have the values listed in the following table for particular base curves in diopters within the series, the coefficient values for other base curves being obtainable from the table by direct interpolation. Base Curve a b c d 10.43 -2.193 .0005 -.0115789 -5.640 X 10 7 11.43 -0.6585 .0005 -.0118166 -1.332 X 10 6 12.43 +0.6188 .0005 -.0121830 -2.105 X 10 6 13.43 +1.920 .0005 -.0125374 -2.888 X 10116 6 14.43 +0.8208 .001 -.0136817 -3.640 X 10 6 15.43 +1.613 .001 -.0138945 -4.820 X 10 6 16.43 +2.197 .001 -.0143155 -6.035 X 10 6 17.43 +2.164 .001 -.0153535 -6.673 X 10 6

Claim 9

A series of aspheric ophthalmic lens surfaces for use with a plurality of lenses having vertex powers extending from about +7.75 diopters to about +18 diopters, each of said plurality of lenses being provided with one of said series of aspheric surfaces on the front surface thereof, wherein said series of aspheric surfaces extends from a base curve of +10.43 diopters to +17.43 diopters and wherein each of the aspheric surfaces in said series has a cross-sectional curvature defined by the equation x a/(by2 + 1) + cy2 + dy4 - a wherein x the distance from the front surface vertex of the lens in a direction parallel to the optical axis of the lens; y the perpendicular distance from the optical axis at any point x; and the coefficients a, b, c and d have the values listed in the following table for particular base curves in diopters within the series, the coefficient values for other base curves being obtainable from the table by direct interpolation. Base Curve a b c d 10.43 -2.193 .0005 -.0115789 -5.640 X 10 7 11.43 -0.6585 .0005 -.0118166 -1.332 X 10 6 12.43 +0.6188 .0005 -.0121830 -2.105 X 10 6 13.43 +1.920 .0005 -.0125374 -2.888 X 10116 6 14.43 +0.8208 .001 -.0136817 -3.640 X 10 6 15.43 +1.613 .001 -.0138945 -4.820 X 10 6 16.43 +2.197 .001 -.0143155 -6.035 X 10 6 17.43 +2.164 .001 -.0153535 -6.673 X 10 6