Telescopic gun sight with rotating optical adjustment mechanism
This invention teaches an optical method for adjusting the point of aim in telescopic gun sights. In one embodiment, a pair of prisms are placed behind the objective lens of a telescopic gun sight such that they can be rotated in a plane perpendicular to the optical axis. The sight's point of aim is adjusted by rotating the two prisms in opposite direction.
1. A telescopic sight for designating a weapon's point of aim when pointed at a target, comprising:
a. an objective lens for forming a first image of the target, said objective lens having a first focal plane and an optical axis,
b. an image-erecting means for converting said first image into an upright and laterally-correct second image, said image erecting means being positioned on the objective optical axis after said objective lens,
c. an eyepiece lens for converting said second image into a virtual third image of the target for convenient viewing by an operator, said eyepiece lens having a second focal plane, said eyepiece lens being positioned on the objective optical axis after said image erecting means,
d. a reticle for indicating the point of aim, said reticle being positioned coplanar with either said first focal plane or said second focal plane,
e. a diverging lens and a converging lens, said diverging lens being positioned on the objective optical axis between said objective lens and said first focal plane, said converging lens being positioned on the objective optical axis between said diverging lens and said first focal plane, and
f. a first wedge prism and a second wedge prism, said first wedge prism and said second wedge prism being positioned on the objective optical axis between said diverging lens and said converging lens, said first wedge prism and said second wedge prism being rotatable around an axis of rotation, said axis of rotation being coaxial with the objective optical axis, said first wedge prism rotation and said second wedge prism rotation being in opposite directions,
whereby the operator can view and use said third image of the target for the purpose of aiming and adjust his point of aim by adjusting the rotation of said first wedge prism and said second wedge prism.
2. The telescopic sight of claim 1 wherein said first wedge prism and said second wedge prism are achromatic prisms.
3. A telescopic sight for designating a weapon's point of aim when pointed at a target, comprising:
a. an objective lens for forming a first image of the target, said objective lens having a first focal plane and an optical axis,
b. an image-erecting means for converting said first image into an upright and laterally-correct second image, said image erecting means being positioned on the objective optical axis after said objective lens, said image erecting means comprising a first converging lens and a second converging lens,
c. an eyepiece lens for converting said second image into a virtual third image of the target for convenient viewing by an operator, said eyepiece lens having a second focal plane, said eyepiece lens being positioned on the objective optical axis after said image erecting means,
d. a reticle for indicating the point of aim, said reticle being positioned coplanar with said second focal plane, and
e. a first wedge prism and a second wedge prism, said first wedge prism and said second wedge prism being positioned on the objective optical axis between said first converging lens and said second converging lens, said first wedge prism and said second wedge prism being rotatable around an axis of rotation, said axis of rotation being coaxial with the objective optical axis, said first wedge prism rotation and said second wedge prism rotation being in opposite directions,
whereby the operator can view and use said third image of the target for the purpose of aiming and adjust his point of aim by adjusting the rotation of said first wedge prism and said second wedge prism.
4. The telescopic sight of claim 3 wherein said first wedge prism and said second wedge prism are achromatic prisms.