Optical system for orthogonalizing image field of projection lens

Claim 2

An optical system for projecting an image of a subject having an effective principal plane onto a viewing screen angularly disposed relative to the effective principal plane of said subject, comprising: a source of light; means including a collimating lens for directing light from said source angularly onto said subject; means including a projecting lens having iTs principal plane substantially parallel to the plane of said screen and angularly disposed relative to the effective principal plane of said subject for receiving light angularly reflected from said subject and directing it to said screen; and means for substantially orthogonalizing said reflected light relative to the principal plane of said projecting lens, said orthogonalizing means comprising a prism located in the path of said reflected light between said subject and said projecting lens, said prism having a rear planar surface through which said reflected light enters and a front planar surface through which said reflected light exits, said rear surface being oriented to be angularly disposed relative to the principal plane of said projecting lens, and said front planar surface being angularly disposed relative to the principal plane of said projecting lens as well as angularly disposed relative to the plane of said rear prism surface, the planes of said front and rear prism surfaces converging at a location shifted from the optical axis of said projecting lens in the same direction as the location at which the plane of said rear prism surface intersects the principal plane of said projecting lens, the angular orientation of said prism being thus chosen to minimize astigmatism effects produced by said prism in said projected image.

Claim 3

An optical system for projecting an image of an illuminated subject having an effective principal plane onto a viewing screen angularly disposed relative to the effective principal plane of said subject, comprising: means including a projecting lens having its principal plane substantially parallel to the plane of said screen and angularly disposed relative to the effective principal plane of said subject for receiving light from said illuminated subject and directing it to said screen; and means for substantially orthogonalizing said reflected light relative to the principal plane of said projecting lens; said orthogonalizing means comprising a prism located in the light path between said subject and said projecting lens, said prism having a rear planar surface through which light enters and a front planar surface through which light exits, said rear surface being oriented to be angularly disposed relative to the principal plane of said projecting lens, and said front planar surface being angularly disposed relative to the principal plane of said projecting lens as well as angularly disposed relative to the plane of said rear prism surface, the planes of said front and rear prism surfaces converging at a location shifted from the optical axis of said projecting lens in the same direction as the location at which the plane of said rear prism surface intersects the principal plane of said projecting lens, and the location at which the principal plane of said projecting lens intersects the effective principal plane of said subject; the angular orientation of said prism being thus chosen to minimize astigmatism effects produced by said prism in said projected image.

Claim 4

An optical system for projecting an image of an illuminated subject having an effective principal plane onto a viewing screen angularly disposed relative to the effective principal plane of said subject, comprising: means including a projecting lens having its principal plane substantially parallel to the plane of said screen and angularly disposed relative to the effective principal plane of said subject for receiving light from said illuminated subject and directing it to said screen; and means for substantially orthogonalizing said reflected light relative to the principal plane of said projecting lens; said orthogonalizing means comprising a prism located in the light path between said subject and said projecting lens, said prism having a rear planar surface through which light enters and a front planar surface through which light exits, said rear surface being oriented to be angularly disposed relative to the principal plane of said projecting lens, and said front planar surface being angularly disposed relative to the principal plane of said projecting lens as well as angularly disposed relative to the plane of said rear prism surface, the planes of said front and rear prism surfaces converging at a location shifted from the optical axis of said projecting lens in the same direction as the location at which the plane of said rear prism surface intersects the principal plane of said projecting lens, and the location at which the principal plane of said projecting lens intersects the effective principal plane of said subject; the angular orientation of said prism being thus chosen to minimize astigmatism effects produced by said prism in said projected image.

Claim 5

An optical system for projecting an image of a subject having an effective principal plane onto a viewing screen angularly disposed relative to the effective principal plane of said subject, comprising: a source of light; means including a collimating lens for directing light from said source angularly onto said subject; means including a projecting lens having its principal plane substantially parallel to the plane of said screen and angularly disposed relative to the effective principal plane of said subject for receiving light angularly reflected from said subject and directing it to said screen; and means for substantially orthogonalizing said reflected light relative to the principal plane of said projecting lens, said orthogonalizing means comprising a prism located in the path of said reflected light between said subject and said projecting lens, said prism having a rear planar surface through which said reflected light enteRs and a front planar surface through which said reflected light exits, said rear surface being oriented to be angularly disposed relative to the principal plane of said projecting lens, and said front planar surface being angularly disposed relative to the principal plane of said projecting lens as well as angularly disposed relative to the plane of said rear prism surface, the planes of said front and rear prism surfaces converging at a location shifted from the optical axis of said projecting lens in the same direction as the location at which the plane of said rear prism surface intersects the principal plane of said projecting lens; said prism being located adjacent the principal plane of said projecting lens and remote from said subject such that all portions of said rear prism surface are separated from said subject by a distance corresponding to a significant portion of the length of said light path between said subject and said projecting lens, and said rear prism surface is provided with a dimension exceeding the corresponding dimension of said subject so as to accommodate divergent light rays reflected from said subject.

Claim 6

An optical system for projecting an image of a subject having an effective principal plane onto a viewing screen angularly disposed relative to the effective principal plane of said subject, comprising: a source of light; means including a collimating lens for directing light from said source angularly onto said subject; means including a projecting lens having its principal plane substantially parallel to the plane of said screen and angularly disposed relative to the effective principal plane of said subject for receiving light angularly reflected from said subject and directing it to said screen; and means for substantially orthogonalizing said reflected light relative to the principal plane of said projecting lens, said orthogonalizing means comprising a prism located in the path of said reflected light between said subject and said projecting lens, said prism having a rear planar surface through which said reflected light enteRs and a front planar surface through which said reflected light exits, said rear surface being oriented to be angularly disposed relative to the principal plane of said projecting lens, and said front planar surface being angularly disposed relative to the principal plane of said projecting lens as well as angularly disposed relative to the plane of said rear prism surface, the planes of said front and rear prism surfaces converging at a location shifted from the optical axis of said projecting lens in the same direction as the location at which the plane of said rear prism surface intersects the principal plane of said projecting lens; said prism being located adjacent the principal plane of said projecting lens and remote from said subject such that all portions of said rear prism surface are separated from said subject by a distance corresponding to a significant portion of the length of said light path between said subject and said projecting lens, and said rear prism surface is provided with a dimension exceeding the corresponding dimension of said subject so as to accommodate divergent light rays reflected from said subject.

Claim 7

An optical system as defined in claim 3, wherein: said source of light is substantially monochromatic; and said prism comprises a single wedge-shaped component having a planar surface of triangular shape normal to the planes of said light entrance and exit surfaces.

Claim 8

An optical system as defined in claim 3, wherein: said source of light is polychromatic; and said prism is a unitary composite structure having a planar surface of trapezoidal configuration normal to the planes of said light entrance and exit surfaces comprising two wedge-shaped components of different materials both having the same median index of refraction and bonded together at an interface with their respectively different vertex angles being on opposite sides of the optical axis of said projecting lens and having said interface as a common side.

Claim 9

An optical system as defined in claim 3, wherein: said source of light is substantially white; and said prism is a unitary composite structure having a planar surface of trapezoidal configuration normal to the planes of said light entrance and exit surfaces comprising three wedge-shaped components, first and second ones of said components being of the same material with the same median index of refraction and substantially identical vertex angles, and the third one of said components being of a different material with a different median index of refraction and a different vertex angle, said components being bonded together at two interfaces with the vertex angles of said first and second components being on one side of said projecting lens axis and the vertex angle of said third component being on the other side of said projecting lens axis, said interfaces respectively including opposite sides of the vertex angle of said third component and one side of each of the vertex angles of said first and second components.

Claim 10

An optical system as defined in claim 6, wherein: said first, second and third prism components are of glass materials.

Claim 11

An optical system as defined in claim 7, wherein: said first and second prism components are of dense barium crown glass and said third prism component is of dense phosphate flint glass.

Claim 12

An optical system as defined in claim 6, wherein: said first, second and third prism components are of optical plastic materials.

Claim 13

An optical system as defined in claim 9, wherein: said first and second prism components are of methyl methacrylate and said third prism component is of vinyl carbazole.

Claim 14

An optical system as defined in claim 3, wherein: said source is polychromatic; and said prism is a unitary composite structure having a planar surface of trapezoidal configuration normal to the planes of said light entrance and exit surfaces comprising several wedge-shaped components with refractive indiceS, dispersions and vertex angles so chosen that the deflection imparted to the light rays incident on the prism is substantially independent of wavelength.