Binocular telescope with controlled parallax
This invention teaches a binocular telescope wherein wedge prisms are positioned in the optical path of each telescope to control the amount of perceived parallax between the left and the right images. In one embodiment, a pair of thin wedge prisms are positioned in front of the objective lenses to optically manipulate the real convergence angle of an object viewed through the binocular telescope. In a second embodiment, wedge prisms are positioned after the eyepiece lenses to manipulate the apparent convergence angle of an object viewed through the binocular telescope. Depending on the position and the orientation of the wedge prisms, the invention produces benefits such as better depth perception, increased field of view, and the possibility to view close objects.
1. A binocular viewing instrument for providing a magnified stereoscopic image of an object to a user comprising a first telescope and a second telescope, said first telescope and said second telescope being mounted side by side, said first telescope and said second telescope each comprising
a. an objective lens,
b. an eyepiece lens, said eyepiece lens having an optical axis and an exit pupil, said exit pupil being located on the eyepiece optical axis at a predetermined distance behind said eyepiece, and
c. a wedge prism, said wedge prism having an apex and a base, said wedge prism being mounted after said eyepiece lens on said optical axis, said wedge prism being mounted before said exit pupil
wherein the wedge prisms are oriented such that
i. the base of the wedge prism in said first telescope faces the base of the wedge prism in said second telescope in order to bend the optical axes of the first telescope's eyepiece lens and the second telescope's eyepiece lens towards each other such that the apparent convergence angle β associated with the stereoscopic view of an object located at a short distance in front of the binocular viewing instrument is reduced,
or
ii. the apex of the wedge prism in said first telescope faces the apex of the wedge prism in said second telescope in order to bend the optical axes of the first telescope's eyepiece lens and the second telescope's eyepiece lens away from each other such that the apparent convergence angle β associated with the stereoscopic view of an object located at a far distance in front of the binocular viewing instrument is increased.
2. The binocular viewing instrument of claim 1 wherein the wedge prisms are achromatic.
3. The binocular viewing instrument of claim 1 wherein the wedge prisms are Fresnel prisms.
4. A binocular viewing instrument for providing a magnified stereoscopic image of an object to a user comprising a first telescope and a second telescope, said first telescope and said second telescope being mounted side by side, said first telescope and said second telescope each comprising
a. an objective lens, said objective lens having an optical axis,
b. an eyepiece lens, and
c. a wedge prism, said wedge prism having an apex and a base, said wedge prism being mounted in front of said objective lens on said optical axis
wherein the wedge prisms are oriented such that
i. the base of the wedge prism in said first telescope faces the base of the wedge prism in said second telescope in order to bend the optical axes of the first telescope's objective lens and the second telescope's objective lens towards each other such that the real convergence angle α associated with the stereoscopic view of an object located at a short distance in front of the binocular viewing instrument is reduced,
or
ii. the apex of the wedge prism in said first telescope faces the apex of the wedge prism in said second telescope in order to bend the optical axes of the first telescope's objective lens and the second telescope's objective lens away from each other such that the real convergence angle α associated with the stereoscopic view of an object located at a far distance in front of the binocular viewing instrument is increased.
5. The binocular viewing instrument of claim 4 wherein the wedge prisms are achromatic.
6. The binocular viewing instrument of claim 4 wherein the wedge prisms are Fresnel prisms.
7. An attachment device for use with a binocular telescope of the type that has a pair of objective lenses and a pair of eyepiece lenses, said attachment device comprising
a. a first housing means and a second housing means, said first housing means and said second housing means being detachably mountable onto said binoculars, said first housing means and said second housing means being mountable in front of the objective lenses of said binocular telescope or behind the eyepiece lenses of said binocular telescope,
b. a first wedge prism and a second wedge prism, said first wedge prism having an apex and a base, said second wedge prism having an apex and a base, said first prism being mounted in said first housing means, said second prism being mounted in said second housing means, said first prism and said second wedge prism being mounted such that their bases face each other or their apexes face each other
whereby a user can view a stereoscopic image of an object through said binocular telescope and manipulate the apparent convergence angle β or the real convergence angle α or both without any change to the original collimation state of said binocular telescope.
8. The attachment device of claim 7 wherein said first wedge prism and said second wedge prism are achromatic prisms.
9. The attachment device of claim 7 wherein said first wedge prism and said second wedge prism are Fresnel prisms.