Lens system comprising plastic and liquid lens elements with aspherical surfaces

Claim 2

An apochromatic lens system comprising two plastic lens elements and a liquid lens element disposed coaxially along an optic axis, said two plastic lens elements being substantially identical to each other, a surface on each of said two plastic lens elements being aspherical.

Claim 3

The lens system of claim 1 wherein said two plastic lens elements and said liquid lens element further coact with each other to focus optical radiation passing through said lens system with a change in focus of less than one-quarter wavelength over said wavelength range between said two discrete wavelengths.

Claim 4

The lens system of claim 1 wherein said two plastic lens elements and said liquid lens element further coact with each other to focus optical radiation passing through said lens system at a third wavelength in said wavelength range between said two discrete wavelengths onto said common focal surface.

Claim 5

The lens system of claim 1 wherein said two plastic lens elements are made of acrylic.

Claim 6

The lens system of claim 4 wherein said liquid lens element is made of an optical liquid having an index of refraction of approximately 1.71035 at a wavelength of 0.58756 micron and an Abbe number of approximately 20.95.

Claim 7

The lens system of claim 4 wherein said liquid lens element is made of an optical liquid having an index of refraction of approximately 1.50012 at a wavelength of 0.58756 micron and an Abbe number of approximately 35.31.

Claim 8

The lens system of claim 4 wherein said liquid lens element is made of an optical liquid having an index of refraction of approximately 1.47011 at a wavelength of 0.58756 micron and an Abbe number of approximately 38.08.

Claim 9

The lens system of claim 1 wherein said plastic lens elements and said liquid lens element are configured and positioned along said optic axis substantially according to an optical prescription as follows: ______________________________________ Surface Radius Thickness No. (inches) (inches) N.sub.d V.sub.d Material ______________________________________ 1 8.36233 0.06000 1.49176 57.46 acrylic 2 -25.10491 0.00142 1.71035 20.95 710209 3 25.10491 0.06000 1.49176 57.46 acrylic 4 -8.36233 9.96452 5 (image plane) ______________________________________ where N d is the index of refraction at the wavelength of the sodium d spectral line and V d is the Abbe number at the same wavelength, and where surfaces No. 2 and No. 3 are spherical, and surfaces No. 1 and No. 4 are hyperboloidal with a conic constant of approximately -2.47.

Claim 10

The lens system of claim 1 wherein said plastic lens elements and said liquid lens element are configured and positioned along said optic axis substantially according to an optical prescription as follows: TABLE I ______________________________________ Surface Radius Thickness No. (inches) (inches) N.sub.d V.sub.d Material ______________________________________ 1 9.56232 0.06000 1.49176 57.46 acrylic 2 -6.31703 0.00142 1.50012 35.31 499352 3 6.31703 0.06000 1.49176 57.46 acrylic 4 -9.56232 9.96198 5 (image plane) ______________________________________ where N d is the index of refraction at the wavelength of the sodium d spectral line and V d is the Abbe number at the same wavelength, and where surfaces No. 2 and No. 3 are spherical, and surfaces No. 1 and No. 4 are hyperboloidal with a conic constant of approximately -3.04.

Claim 11

The lens system of claim 1 wherein said plastic lens elements and said liquid lens element are configured and positioned along said optic axis substantially according to an optical prescription as follows: ______________________________________ Surface Radius Thickness No. (inches) (inches) N.sub.d V.sub.d Material ______________________________________ 1 10.79058 0.06000 1.49176 57.46 acrylic 2 -4.77990 0.00142 1.47011 38.08 470380 3 4.77990 0.06000 1.49176 57.46 acrylic 4 -10.79058 9.95944 5 (image plane) ______________________________________ where N d is the index of refraction at the wavelength of the sodium d spectral line and V d is the Abbe number at the same wavelength, and where surfaces No. 2 and No. 3 are spherical, and surfaces No. 1 and No. 4 are hyperboloidal with a conic constant of approximately -4.36.

Claim 12

A lens system comprising two acrylic lens elements and a liquid lens element disposed coaxially along an optic axis, said two acrylic lens elements being substantially identical to each other, a surface on each of said two acrylic lens elements being aspherical, said two acrylic lens elements and said liquid lens element coacting with each other to focus optical radiation at two discrete wavelengths passing through said lens system onto a common focal surface, said liquid lens element being made of an optical liquid having an index of refraction of approximately 1.71035 at a wavelength of 0.58756 micron and an Abbe number of approximately 20.95.

Claim 13

A lens system comprising two acrylic lens elements and a liquid lens element disposed coaxially along an optic axis, said two acrylic lens elements being substantially identical to each other, a surface on each of said two acrylic lens elements being aspherical, said two acrylic lens elements and said liquid lens element coacting with each other to focus optical radiation at two discrete wavelengths passing through said lens system onto a common focal surface, said liquid lens element being made of an optical liquid having an index of refraction of approximately 1.71035 at a wavelength of 0.58756 micron and an Abbe number of approximately 20.95.

Claim 14

A lens system comprising two acrylic lens elements and a liquid lens element disposed coaxially along an optic axis, said two acrylic lens elements being substantially identical to each other, a surface on each of said two acrylic lens elements being aspherical, said two acrylic lens elements and said liquid lens element coacting with each other to focus optical radiation at two discrete wavelengths passing through said lens system onto a common focal surface, said liquid lens element being made of an optical liquid having an index of refraction of approximately 1.50012 at a wavelength of 0.58756 micron and an Abbe number of approximately 35.31.

Claim 15

A lens system comprising two acrylic lens elements and a liquid lens element disposed coaxially along an optic axis, said two acrylic lens elements being substantially identical to each other, a surface on each of said two acrylic lens elements being aspherical, said two acrylic lens elements and said liquid lens element coacting with each other to focus optical radiation at two discrete wavelengths passing through said lens system onto a common focal surface, said liquid lens element being made of an optical liquid having an index of refraction of approximately 1.50012 at a wavelength of 0.58756 micron and an Abbe number of approximately 35.31.