Multifocal birefringent lens system

Claim 2

A multifocal non-achromatized birefringent lens system which comprises: a) a first lens component which is a birefringent lens component; and, b) a second lens component adjacent to said first lens component, the curvatures of the opposed surfaces of the first and second lens components being substantially identical or complementary, said second lens component being (i) a birefringent lens component possessing an optic axis of different orientation than that of the optic axis of birefringent lens component (a) or (ii) a birefringent lens component wherein both indices of refraction differ from those of birefringent lens component (a) or (iii) a birefringent lens component wherein the refraction index for the ordinary light waves is the same as that for birefringent lens component (a) but wherein the refractive index for the extraordinary light waves differs from that for birefringent lens component (a) or (iv) a birefringent lens component wherein the refractive index for the extraordinary light waves is the same as that for birefringent lens component (a) but wherein the refractive index for the ordinary light waves differs from that for birefringent lens component (a) or (v) an isotropic lens component, provided, that for light which is incident in parallel with the lens axis, said lens system possesses simultaneously at least two foci each of which is positioned at any preselected positive or negative focal distance on the axis of the lens system and further provided that any one surface of either the first or second lens component is given a curvature in independence of said preselected foci.

Claim 3

The lens system of Claim 1 of perfect geometry.

Claim 4

The lens system of Claim l of non-perfect geometry.

Claim 5

The lens system of Claim 1 exhibiting no unwanted focus or foci.

Claim 6

The lens system of Claim 1 wherein one or more of the birefringent lens components utilized therein is fabricated from a polymeric birefringent material.

Claim 7

The lens system of Claim 4 employed as an ophthalmic lens.

Claim 8

The lens system of Claim 6 wherein the ophthalmic lens is a contact lens.

Claim 9

The lens system of Claim 1 wherein birefringent lens component (a) is combined with at least one other birefringent lens component (b)(i), (ii), (iii) and/or (iv).

Claim 10

The lens system of Claim 1 wherein birefringent lens component (a) is combined with at least one isotropic lens component (b)(v).

Claim 11

The lens system of Claim 1 further comprising at least one polarizer means other than a birefringent lens and/or at least one polarizing filter.

Claim 12

An optical device, instrument or apparatus incorporating the lens system of Claim 1.

Claim 13

A multifocal birefringent lens system which is achromatic in at least one focus or exhibits a predetermined amount of chromatic aberration in at least one focus which comprises: a) a first lens component which is a birefringent lens component possessing an optic axis which is substantially perpendicular to the lens axis; and, b) a second lens component adjacent to said first lens component, said second lens component being (i) a birefringent lens component possessing an optic axis of different orientation than that of the optic axis of birefringent lens component (a) or (ii) a birefringent lens component wherein both indices of refraction differ from those of birefringent lens component (a) or (iii) a birefringent lens component wherein the refraction index for the ordinary light waves is the same as that for birefringent lens component (a) but wherein the refractive index for the extraordinary light waves differs from that for birefringent lens component (a) or (iv) a birefringent lens component wherein the refractive index for the extraordinary light waves is the same as that for birefringent lens component (a) but wherein the refractive index for the ordinary light waves differs from that for birefringent lens component (a) or (v) an isotropic lens component, provided, that for light which is incident in parallel with the lens axis, said lens system simultaneously possesses at least two foci each of which is positioned at any preselected positive or negative focal distance on the axis of the lens system and further provided that at least the focal distance of one of the two foci is essentially equal for of at least two different wavelengths of the focused light.

Claim 14

A multifocal birefringent lens system which is achromatic in at least one focus or exhibits a predetermined amount of chromatic aberration in at least one focus which comprises: a) a first lens component which is a birefringent lens component possessing an optic axis which is substantially perpendicular to the lens axis; and, b) a second lens component adjacent to said first lens component, said second lens component being (i) a birefringent lens component possessing an optic axis of different orientation than that of the optic axis of birefringent lens component (a) or (ii) a birefringent lens component wherein both indices of refraction differ from those of birefringent lens component (a) or (iii) a birefringent lens component wherein the refraction index for the ordinary light waves is the same as that for birefringent lens component (a) but wherein the refractive index for the extraordinary light waves differs from that for birefringent lens component (a) or (iv) a birefringent lens component wherein the refractive index for the extraordinary light waves is the same as that for birefringent lens component (a) but wherein the refractive index for the ordinary light waves differs from that for birefringent lens component (a) or (v) an isotropic lens component, provided, that for light which is incident in parallel with the lens axis, said lens system simultaneously possesses at least two foci each of which is positioned at any preselected positive or negative focal distance on the axis of the lens system and further provided that at least the focal distance of one of the two foci is essentially equal for of at least two different wavelengths of the focused light.

Claim 15

The lens system of Claim 12 of perfect geometry.

Claim 16

The lens system of Claim 12 of non-perfect geometry.

Claim 17

The lens system according to Claim 12 in which the birefringence of the birefringent medium from which birefringent lens component (a) is fabricated is identical for two different wavelengths.

Claim 18

The lens system of Claim 12 wherein at least one birefringent lens component is combined with at least two isotropic lens components and the lens system satisfies the following equation:

Claim 19

The lens system of Claim 12 wherein at least two birefringent lens components are combined with at least two isotropic lens components and the lens system satisfies the following equation:

Claim 20

The lens system of Claim 12 further comprising at least one polarizer means other than a birefringent lens and/or at least one polarizing filter.

Claim 21

An optical device, instrument or apparatus incorporating the lens system of Claim 12.