Light-beam steering apparatus

Claim 2

A light-beam steering apparatus, comprising in combination first and second steering mirrors, first and second suspension means supporting said first and second mirrors, respectively, for angular displacement about parallel axes to deflect an incident light beam in a common plane perpendicular to said parallel axes of displacement, first and second deflection coils mounted on said first and second suspension means, respectively, and suspended in a magnetic field whereby the associated mirror may be displaced by passage of a current through the corresponding coil, and means defining an optical system between the mirrors for causing the plane of deflection of the light beam after reflection by the first mirror and prior to incidence on said second mirror to be rotated into a plane inclined to the said common plane of deflection, said optIcal system including means defining first and second reflectors cooperatively disposed with respect to each other for causing a light beam incident on the first reflector in one plane to pass between the reflectors in a direction generally perpendicular to the said one plane and emerge from the second reflector in a plane generally parallel to said one plane and at an angle to its direction of incidence, the optical system further comprising lens means, said mirrors being disposed at conjugate points of said lens means.

Claim 3

Apparatus as claimed in claim 1 wherein the optical system comprises a third reflector between the first steering mirror and the lens means.

Claim 4

Apparatus as claimed in claim 2 including a further lens preceding said first mirror in the path of said light beam and arranged to focus said beam at said third reflector, said third reflector lying at the focus of said lens means.

Claim 5

Apparatus as claimed in claim 1 in which said first and second reflectors are internally reflecting prisms.

Claim 6

Apparatus as claimed in claim 1 in which each of said first and second reflectors is disposed to deflect the beam through about 90* and the planes of deflection of said first and second reflectors are approximately perpendicular to one another.

Claim 7

Apparatus as claimed in claim 1 in which the optical path length from said first mirror to said lens means is equal to the optical path length from said lens means to said second mirror.

Claim 8

A light beam steering apparatus, comprising in combination: first and second steering mirrors; first and second suspension means supporting said first and second steering mirrors, respectively, for angular displacement about parallel axes to deflect an incident light beam in a common plane perpendicular to said parallel axes of displacement, first and second deflection coils mounted on said first and second suspension means, respectively, and suspended in a magnetic field whereby the associated mirror is displaceable by passage of a current through the corresponding coil, an optical system defining a light path between said mirrors for conveying said light beam therebetween, said optical system including reflector means on said light path between said mirrors for rotating the plane of deflection of said light beam into a plane transverse to said common plane of deflection, whereby the light beam passes between the first steering mirror and said reflector means in said common plane of deflection and passes from the reflector means to said second steering mirror in said transverse plane of deflection, said optical system further including lens means in said light path between said mirrors and spaced from said mirror means, said steering mirrors being disposed at conjugate points of said lens means whereby each of the steering mirrors is imaged at the other via said lens means.

Claim 9

A light beam steering apparatus, comprising in combination: first and second steering mirrors; first and second suspension means supporting said first and second steering mirrors, respectively, for angular displacement about parallel axes to deflect an incident light beam in a common plane perpendicular to said parallel axes of displacement, first and second deflection coils mounted on said first and second suspension means, respectively, and suspended in a magnetic field whereby the associated mirror is displaceable by passage of a current through the corresponding coil, an optical system defining a light path between said mirrors for conveying said light beam therebetween, said optical system including reflector means on said light path between said mirrors for rotating the plane of deflection of said light beam into a plane transverse to said common plane of deflection, whereby the light beam passes between the first steering mirror and said reflector means in said common plane of deflection and passes from the reflector means to said second steering mirror in said transverse plane of deflection, said optical system further including lens means in said light path between said mirrors and spaced from said mirror means, said steering mirrors being disposed at conjugate points of said lens means whereby each of the steering mirrors is imaged at the other via said lens means.

Claim 10

Apparatus as claimed in claim 7 in which said reflector means includes a reflecting surface on said light path near an intermediate focus of said lens means.

Claim 11

Apparatus as claimed in claim 8 in which the spacing from said lens means to said steering mirrors is the same for both steering mirrors, said distance being one or more focal lengths of said lens means.

Claim 12

Apparatus as claimed in claim 9 in which the spacing between said lens means and said reflecting surface is one focal length of said lens means.

Claim 13

Apparatus as claimed in claim 10 in which said lens means comprises first and second lenses disposed on said light path at a distance of one focal length from said first and second steering mirrors, respectively, said reflecting means comprises a dove prism evenly spaced between the first and second lenses on said light path, said first and second lenses having the same focal length and being separated on said light path by a distance equal to two focal lengths thereof, and including first and second reflectors disposed, respectively, between said first lens and said dove prism and between said dove prism and said seconD lens and on said light path, said first and second lenses and said first and second reflectors being disposed in said common plane.

Claim 14

Apparatus as claimed in claim 10 in which said lens means comprises a lens disposed in said light path at a distance of two focal lengths thereof from each of said first and second steering mirrors, said reflecting surface being spaced between said lens and said first steering mirror at distance of one focal length of said lens from each, said reflector means further comprising first and second reflectors skewed with respect to each other and aligned transversely of said common plane for carrying out said rotation of said light beam, said first and second reflectors being disposed between said lens and second mirror, a further lens of focal length double that of said first mentioned lens and spaced along the path by which said light beam approaches said first steering mirror at the focal length of said first mentioned lens for focusing said beam on said reflecting surface.

Claim 15

Apparatus as claimed in claim 10 in which said reflector means comprises three reflective prisms disposed sequentially along said light path between said steering mirrors and said lens means comprises at least one lens disposed in said light path in cooperating relation with said reflector means.