Electro-optical variable focal length lens using optical ring polarizer

Claim 2

An electrically controlled variable focal length lens system for controlling the divergence of polarized light such as the output of a laser, said lens system comprising: a. a solid body of crystalline material having a plurality of electrodes embedded therein, said electrodes being positioned in said crystal to produce at every internal point therein a birefringence proportional only to the square of the radial distance from the center of the lens to the given point, the slow axis of said crystal being everywhere tangent to its circle of consant refringence, said electrically controlled crystal thereby being adapted to affect ring-polarized light; b. means positioned ahead of said lens for receiving linearlypolarized light and for converting said light into ringpolarized light; and c. means to apply control voltages to said electrodes.

Claim 3

Apparatus as in claim 1 and further including: a. means positioned behind said lens for receiving ring-polarized light from said lens and for converting said ring-polarized light into linearly polarized light.

Claim 4

Apparatus as in claim 1 wherein said solid body has a cylindrical shape and said electrodes are rod shaped and are positioned therein so that when said solid body is viewed in cross section said electrodes lie at the corners of a regular polygon.

Claim 5

Apparatus as in claim 3 wherein adjacent electrodes are held at opposite polarities by said control voltages.

Claim 6

Apparatus as in claim 3 wherein said regular polygon is a hexagon and there are six of said electrodes, one at each corner of said hexagon.

Claim 7

Apparatus as in claim 1 wherein said solid body of crystalline material has 3m(C3v) symmetry.

Claim 8

An electrically controlled variable focal length lens system for controlling the divergence of polarized light such as the output of a laser, said lens system comprising: a. a solid body of crystalline material having a plurality of electrodes embedded therein, said electrodes being positioned in said crystal to produce at every internal point therein a birefringence proportional only to the square of the radial distance from the center of the lens to the given point, the slow axis of said crystal being everywhere tangent to its circle of constant refringence, said electrically controlled crystal thereby being adapted to affect ring-polarized light; b. means positioned ahead of said lens for receiving linearly-polarized light and for converting said light into ring-polarized light, said means comprising a plano-ramp shaped disc of birefringent material having a thickness which varies linearly through 2 pi radians as a function of angle from an initial radial line from a minimum value at zero radians to a maximum value equal to said minimum value plus the quotient of twice the design wavelength divided by the birefringence of the material of the disc, said design wavelength being the wavelength of the radiation to be transmitted through the disc, and said disc being followed by a quarter wave plate; c. means positioned behind said lens for receiving ring-polarized light from said lens and for converting said ring-polarized light into linearly polarized light, said means comprising a quarter wave plate followed by a plano-ramp shaped disc of birefringent material having a thickness which varies linearly through 2 pi radians as a function of angle from an initial radial line from a minimum value at zero radians to a maximum value equal to said minimum value plus the quotient of twice the design wavelength divided by the birefringence of the material of the disc, said design wavelength being the wavelength of the radiation to be transmitted through the disc and d. means to apply control voltages to said electrodes.

Claim 9

An electrically controlled variable focal length lens system for controlling the divergence of polarized light such as the output of a laser, said lens system comprising: a. a solid body of crystalline material having a plurality of electrodes embedded therein, said electrodes being positioned in said crystal to produce at every internal point therein a birefringence proportional only to the square of the radial distance from the center of the lens to the given point, the slow axis of said crystal being everywhere tangent to its circle of constant refringence, said electrically controlled crystal thereby being adapted to affect ring-polarized light; b. means positioned ahead of said lens for receiving linearly-polarized light and for converting said light into ring-polarized light, said means comprising a plano-ramp shaped disc of birefringent material having a thickness which varies linearly through 2 pi radians as a function of angle from an initial radial line from a minimum value at zero radians to a maximum value equal to said minimum value plus the quotient of twice the design wavelength divided by the birefringence of the material of the disc, said design wavelength being the wavelength of the radiation to be transmitted through the disc, and said disc being followed by a quarter wave plate; c. means positioned behind said lens for receiving ring-polarized light from said lens and for converting said ring-polarized light into linearly polarized light, said means comprising a quarter wave plate followed by a plano-ramp shaped disc of birefringent material having a thickness which varies linearly through 2 pi radians as a function of angle from an initial radial line from a minimum value at zero radians to a maximum value equal to said minimum value plus the quotient of twice the design wavelength divided by the birefringence of the material of the disc, said design wavelength being the wavelength of the radiation to be transmitted through the disc and d. means to apply control voltages to said electrodes.

Claim 10

Apparatus as in claim 7 wherein said solid body has a cylindrical shape and saiD electrodes are rod shaped and are positioned therein so that when said solid body is viewed in cross section said electrodes lie at the corner of a regular polygon.

Claim 11

Apparatus as in claim 8 wherein said solid body of crystalline material has 3m(C3v) symmetry.

Claim 12

Apparatus as in claim 9 wherein adjacent electrodes are held at opposite polarities by said control voltages.

Claim 13

Apparatus as in claim 10 wherein said regular polygon is a hexagon and there are six of said electrodes, one at each corner of said hexagon.