Multi-spectral imaging system

Claim 2

A multi-spectral imaging system, character­ized by a) first means (19) for reflecting and passing electromagnetic radiation; b) second means (18) for reflecting and passing electromagnetic radiation, in proximity with said first means (19); and c) means (14) for receiving and/or emitting electromagnetic radiation, in proximity with said second means (18).

Claim 3

Apparatus according to claim 1, character­ized by means (30, 40) for detecting and/or generating infrared radiation and comprising a focal plane (30).

Claim 4

Apparatus according to claim 1 or 2, character­ized in that said first means (19) comprises an outer section (20) and a center section (28) with said outer section (20) having the property of reflecting millimeter (32) and infrared (34) electromagnetic radiation and said center section (28) having the property of reflecting millimeter electromagnetic radiation (32) and passing infrared electromagnetic radiation (34).

Claim 5

Apparatus according to claim 3, character­ized in that said center section (28) of said first means (19) comprises a germanium aspheric substrate (28) having dichroic thin film coatings (24, 26).

Claim 6

Apparatus according to one of the preceding claims 1, characterized in that said second means (18) comprises a material for reflecting infrared radiation (34) and passing millimeter wave radiation (32).

Claim 7

Apparatus according to claim 5, character­ized in that said second means (18) comprises a quartz aspheric substrate having a dichroic thin film coating (22).

Claim 8

Apparatus according to one of the preceding claims, characterized in that said first means (19) has a substantially parabolic shape, preferably a rotationally symmetric shape.

Claim 9

Apparatus according to one of the preceding claims, characterized in that said second means (18) has an aspheric shape, preferably a substantially elliptical rotationally symmetric shape.

Claim 10

Apparatus according to one of the claims 2 to 8, characterized in that a) said first (19) and second (18) means have focal centers on a common optical axis (16) perpendicular to central surfaces of said first and second means; b) said means (14) for receiving and/or emitting radiation has a center on said common axis (16) and has substantially central directions of emitted and received radiation parallel to said common axis; and c) said focal plane (30) has a center of said plane on said common axis (16) and has a surface perpendicular to said common axis.

Claim 11

Apparatus according to claim 7, 8 or 9, charac­terized in that said first means (19) has its concave side facing said means (14) for receiving and/or emitting electromagnetic radiation.

Claim 12

Apparatus according to one of the claims 7 to 10, characterized in that said second means (18) has its concave side facing said means (14) for receiving and/or emitting electromagnetic radiation.

Claim 13

Apparatus according to one of the claims 2 to 11, characterized in that said second means (18) is physically situated between said means (14) for receiving and/or emitting radiation and said first means (19) and that said first means (19) is physically situated between said second means (18) and said focal plane (30).

Claim 14

Apparatus according to one of the preceding claims, characterized in that said means for receiving and/or emitting electromagnetic radiation is a millimeter wave feedhorn (14).

Claim 15

Apparatus according to one of the preceding claims, characterized by : a) first means (19) for receiving millimeter wave (32, 38) and infrared radiation (34) from free space and reflecting said radiation; b) second means (18) for receiving said radiation from said first reflecting means (19), reflecting said reflected infrared radiation (34), passing said reflected millimeter wave radiation (32) from said first reflecting means (19), and passing millimeter wave radiation (38) from a field of view; c) third means (28, 26), in a physical unit incorporating said first means (19), for receiving and reflecting said millimeter wave radiation (38) from said field of view, and passing infrared radiation (34) reflected from said second means (18); d) fourth means (14) for receiving and/or emitting millimeter wave radiation; and e) fifth means (40) for receiving and converting infrared radiation into electrical signals for transmission to a viewing device.