Biocular viewing apparatus

Claim 2

Optical apparatus for biocular viewing having an optical axis comprising an objective lens for receiving light from a distant scene or object and producing an initial image thereof in an image plane, a biocular magnifying eyepiece lens having an object plane, relay lens means disposed between said image plane and said object plane, first reflector means associated with said relay lens means so that light from said initial image travels via the relay lens means and said first reflector means to form substantially in said object plane a first image tilted with respect to the optical axis, and second reflector means associated with said relay lens means so that light from said initial image travels via the relay lens means and said second reflector means to form substantially in said object plane a second image tilted with respect to the optical axis, each of said first and second reflector means comprising a pair of reflecting faces with said faces being tilted with respect to each other and at least one of said faces being tilted with respect to the optical axis so that said second image is tilted in a sense or direction of tilt opposite to that of said first image.

Claim 3

Apparatus according to claim 1 wherein said reflecting faces are provided by plane mirrors.

Claim 4

Apparatus according to claim 1 wherein said relay lens means consists of a single relay lens, and said first and second reflector means each comprise one reflecting face disposed in the light path between said image plane and the relay lens and another reflecting face disposed in the light path between the relay lens and said object plane.

Claim 5

Optical apparatus for biocular viewing having an optical axis comprising an objective lens for receiving light from a distant scene or object and producing an initial image thereof in an image plane, a biocular magnifying eyepiece lens having an object plane, a relay lens, a first pair of reflecting faces positioned at off-axis locations one between said image plane and the relay lens and the other between the relay lens and said object plane, and a second pair of reflecting faces positioned at off-axis locations one between the image plane and the relay lens and the other between the relay lens and said object plane, wherein the reflecting faces between the image plane and the relay lens reflect light from the initial image produced by the objective lens to produce a pair of off-axis virtual objects for the relay lens, and wherein the reflecting faces between the relay lens and said object plane are in tilted disposition with respect to the optical axis and with respect to each other so as to produce from the light transmitted through the relay lens from said respective virtual objects a pair of images tilted in opposite senses or directions with respect to the optical axis and substantially in the object plane of the eyepiece lens.

Claim 6

Optical apparatus for biocular viewing having an optical axis comprising an objective lens for receiving light from a distant scene or object and producing an initial image thereof in an image plane, a biocular magnifying eyepiece lens having an object plane, a relay lens, a first pair of reflecting faces positioned at off-axis locations one between said image plane and the relay lens and the other between the relay lens and said object plane, and a second pair of reflecting faces positioned at off-axis locations one between the image plane and the relay lens and the other between the relay lens and said object plane, wherein the reflecting faces between the image plane and the relay lens reflect light from the initial image produced by the objective lens to produce a pair of off-axis virtual objects for the relay lens, and wherein the reflecting faces between the relay lens and said object plane are in tilted disposition with respect to the optical axis and with respect to each other so as to produce from the light transmitted through the relay lens from said respective virtual objects a pair of images tilted in opposite senses or directions with respect to the optical axis and substantially in the object plane of the eyepiece lens.

Claim 7

Apparatus according to claim 1 wherein said relay lens means consists of two relay lenses, and each of said first and second reflector means comprises a pair of reflecting faces located in the light path between a respective relay lens and said object plane.

Claim 8

Optical apparatus for biocular viewing having an optical axis comprising an objective lens for receiving light from a distant scene or object and producing an initial image thereof in an image plane, a biocular magnifying eyepiece lens having an object plane, a first relay lens located at an off-axis position between said image plane and said object plane and to one side of a plane containing the optical axis, a first pair of reflecting faces associated with said first relay lens and located at an off-axis position to said one side of said plane containing the optical axis and in relatively tilted disposition such that light from said initial image transmitted through said first relay lens and reflected from said first pair of reflecting faces forms substantially in said object plane a first image tilted with respect to the optical axis, a second relay lens located at an off-axis position between said image plane and said object plane and to the other side of said plane containing the optical axis, and a second pair of reflecting faces associated with said second relay lens and located at an off-axis position to said other side of said plane containing the optical axis and in relatively tilted disposition such that light from said initial image transmitted through said second relay lens and reflected from said second pair of reflecting faces forms substantially in said object plane a second image tilted with respect to the optical axis in a sense or direction of tilt opposite to that of said first image.

Claim 9

Optical apparatus for biocular viewing having an optical axis comprising an objective lens for receiving light from a distant scene or object and producing an initial image thereof in an image plane, a biocular magnifying eyepiece lens having an object plane, a first relay lens located at an off-axis position between said image plane and said object plane and to one side of a plane containing the optical axis, a first pair of reflecting faces associated with said first relay lens and located at an off-axis position to said one side of said plane containing the optical axis and in relatively tilted disposition such that light from said initial image transmitted through said first relay lens and reflected from said first pair of reflecting faces forms substantially in said object plane a first image tilted with respect to the optical axis, a second relay lens located at an off-axis position between said image plane and said object plane and to the other side of said plane containing the optical axis, and a second pair of reflecting faces associated with said second relay lens and located at an off-axis position to said other side of said plane containing the optical axis and in relatively tilted disposition such that light from said initial image transmitted through said second relay lens and reflected from said second pair of reflecting faces forms substantially in said object plane a second image tilted with respect to the optical axis in a sense or direction of tilt opposite to that of said first image.

Claim 10

Apparatus according to claim 1 including a field lens located substantially in said image plane of the objective lens.

Claim 11

Apparatus according to claim 1 comprising folding means to fold the optical axis at at least one position.

Claim 12

Apparatus according to claim 8 wherein said folding means comprise at least one reflector located in the light path between the objective lens and its image plane.

Claim 13

Apparatus according to claim 8 wherein said folding means comprise a reflector located in the light path between said first and second reflector means and said object plane of the eyepiece lens.

Claim 14

Apparatus according to claim 8 wherein a fold in the optical axis is provided at a position between the objective lens and its image plane, comprising two reflectors disposed to reflect light in directions towards the respective light paths via said first reflector means and said second reflector means.

Claim 15

Apparatus according to claim 3 comprising two reflectors which provide a fold in the optical axis at a position between the objective lens and its image plane, wherein one of the reflectors is disposed to reflect light generally towards one of the reflecting faces between said image plane and the relay lens while the other reflector is disposed to reflect light generally towards the other of the reflecting faces between said image plane and the relay lens.

Claim 16

Apparatus according to claim 5 comprising two reflectors which provide a fold in the optical axis at a position between the objective lens and its image plane, wherein one of the reflectors is disposed to reflect light generally towards said first relay lens while the other reflector is disposed to reflect light generally towards said second relay lens.

Claim 17

A combined day and night viewing system incorporating apparatus according to claim 1 and having lens components common to respective day and night viewing paths.

Claim 18

A system according to claim 14 comprising beam-splitter means associated with the biocular magnifying eyepiece lens and having a partially reflecting/partially transmitting interface which can reflect light in one of the viewing paths towards an observer viewing through the eyepiece lens, and through which light in the other viewing path can be transmitted to the observer viewing through the eyepiece lens.

Claim 19

A system according to claim 15 wherein the beam-splitter means is located between a back part of the eyepiece lens through which the observer views for both the day and night viewing paths, and separate effective front parts of the lens designed to suit the particular respective optical requirements of the respective day and night viewing paths.

Claim 20

A system according to claim 14 having an objective lens component through which light travels to both viewing paths and comprising respective light directing means adapted to direct light transmitted through the objective lens component into the respective day and night viewing paths.

Claim 21

A system according to claim 14 wherein separate field lenses are provided in the day and night viewing paths to suit the particular respective optical requirements.

Claim 22

A system according to claim 17 wherein the objective lens component is backed by one mirror which reflects light transmitted through the objective lens component towards a field lens disposed at the entrance to an image intensifier tube in the night vision path, and by a further pair of mirrors which reflect light transmitted through the objective lens component towards another field lens disposed substantially in said image plane of the objective lens in the day vision path.