Receive and display optical raster scan generator

Claim 2

Apparatus for simultaneously producing non-astigmatic synchronized receive and display mode raster scans for infrared detector upconversion devices suitable for use with an afocal magnifying system, said apparatus being characterized by: a. a frame; b. a rotatable azimuth scan generating mirror structure mounted for rotation about a spin axis relative to said frame and having a plurality of radially directed axes defined on and rotating with said structure, each of said radial axes being perpendicular to said spin axis, said axes being substantially uniformly spaced angularly about said spin axis, a plurality of mirror surfaces on said mirror structure, each said mirror surface being perpendicular to a different one of said radial axes; c. elevation scan generating mirror means mounted for oscillation relative to said frame about an oscillation axis which is parallel to a plane which in turn is perpendicular to and displaced from said spin axis; d. said oscillating mirror means being positioned in each of two light paths each of which periodically includes each of said rotating mirror surfaces, said oscillation axis orthogonally passing through a point on a locus of oscillation centers, said locus lying in the plane of the central rays respectively incident on and reflected from said oscillating mirror and making an angle Beta with said reflected ray which is equal to the angle of incidence of said central ray on said oscillating mirror when said mirror is in its nominal central position so that the orthogonally directed scans produced by said rotatable mirror and said oscillating mirror both appear to originate from substantially the same spot on a surface of said rotatable mirror; and e. one of said light paths receiving radiation from a scanned scene and transmitting it to an infrared detector, the other of said light paths transmitting radiation from a local source to a display means, said transmitted radiation being intensity modulated responsively to the output of said detector in order to produce a visiable image of said scene, said scans being synchronized by the inclusion of said oscillating mirror in each of said light paths.

Claim 3

Apparatus as in claim 1 wherein at least one of said light paths includes an afocal magnifying optical element.

Claim 4

Apparatus as in claim 1 wherein: a. each of said two light paths at any given instant includes a different one of the mirror surfaces of said rotatable mirror structure for generating the azimuth scan of said receive and display modes respectively and also includes a different portion of mirror surface of said oscillating mirror means for generating the elevation component of scan of said receiving and display modeS respectively.

Claim 5

Apparatus as in claim 3 wherein said different surfaces of said rotatable mirror structure are immediately adjacent surfaces on said structure and wherein one of said paths has the incident ray on one of said surfaces parallel to the reflected ray from the adjacent surface of said rotatable structure in the other of said paths and wherein the incident and reflected rays in each of said paths make an angle delta with each other in their common plane which is equal to 360* divided by the number of mirror surfaces on said rotatable mirror structure, said angles extending in opposite direction in said plane from said parallel rays.

Claim 6

Apparatus as in claim 4 wherein said oscillating mirror has a length extending perpendicularly to its axis of oscillation which is greater than the length of a single mirror surface on said rotatable mirror structure in order to accommodate both of said light paths including adjacent surfaces on said rotatable mirror on a single surface of said oscillating mirror.

Claim 7

Apparatus as in claim 1 and further characterized by: a. said frame having at least five directional axes defined with respect thereto for each of two light paths; means coacting with said oscillating mirror to define, when said oscillating mirror is at a preselected central nominal design position in its wing, the first of said optical axes extending in the direction of transmission of radiation between said coacting means and said oscillating mirror; said second optical axis extending in the direction of transmission of radiation between said oscillating mirror and said rotatable mirror structure, the angle Beta between the normal to said oscillating mirror surface and said first axis being equal to the angle between said normal and said second axis; said second optical axis being positioned when said oscillating mirror surface is in a central design position in a plane which is substantially perpendicular to the surface of said rotatable mirror structure, said second axis intercepting said first axis on the surface of said oscillating mirror and being turned from said first axis through an angle equal to (180 - 2 Beta )*; a third axis intercepting said second axis at a distance A csc2 Beta from the interception of said first and second axes and turned from said axes through an angle Beta , said first, second, and third axis being coplanar, said third axis comprising a locus line of the centers of oscillation of said oscillating mirror; a fourth axis perpendicular to said second axis and parallel to the plane of said first three axes, said fourth axis comprising the spin axis of said rotatable mirror structure; and a fifth axis intercepting said second axis at a distance A from said interception of said first and second axes, said second and fifth axes defining a plane perpendicular to the plane of said first three axes and said fifth axis being turned from said second axis through an angle delta ; a rotatable mirror structure rotatable about said fourth axis and including a plurality of radial directions defined thereon perpendicular to said fourth axis, said structure having a plurality of mirror surfaces thereon, each of said surfaces being perpendicular to a different one of said radial directions, said mirror surfaces being positioned to intercept said second axis consecutively when said structure is rotated; an oscillating mirror structure having limited oscillation about an axis centered on and perpendicular to said third axis and parallel to the plane of said second and fifth axes, said oscillating mirror structure having mirror surface means thereon intercepting said first and second axes; each of said light paths including said oscillating mirror structure and having said five axes associated with it, the first and second axes in each of said paths being separate from and parallel to each other; said third locus line axis and said fourth rotatable mirror spin axis being the same for each oF said paths; said fifth axis in each of said light paths making an angle delta with said second axis in the same light path, said fifth axes in said two light paths being coplanar with each other and making an angle 2 delta with each other where said angle delta has a value equal to 360* divided by the number of surfaces of said rotatable mirror structure.

Claim 8

Apparatus as in claim 6 in which rotation of said mirror structure produces an optical sweep about said fifth axis in each of said light paths through a usable angle 2 Alpha , whereby radiation delivered in a bundle substantially along said second axis to said mirror surfaces of said rotatable mirror structure is projected and sweeps through at least an angle 2 Alpha from said fifth axis about an axis parallel to said fourth axis and radiation delivered, at least within an angular region 2 Alpha of said fifth axis, to said mirror surfaces of said rotatable mirror structure is scanned and delivered along said second axis to said oscillating mirror structure.

Claim 9

Apparatus as in claim 6 wherein the oscillation of said oscillating mirror structure is through an angle gamma whereby radiation delivered substantially along said first axis in either of said light paths to said oscillating mirror is projected and swept at least through an angle 2 gamma , and radiation received through at least an angle 2 gamma about an axis passing through the intersection of said second and fifth axes and perpendicular to the planes of said first and second axes at least through an angle 2 gamma is delivered and projected substantially along said first axis.

Claim 10

Apparatus as in claim 7 and further comprising means in one of said light paths for producing a pencil of beams of light substantially along said first axis and means in the other of said light paths for detecting a pencil of infrared radiation transmitted substantially along said first axis therein.