GB1393535A - Scan mechanism for thermal imaging - Google Patents

Abstract

1393535 Optical scanning HAWKER SIDDELEY DYNAMICS Ltd 17 July 1972 [16 July 1971] 33435/71 Heading H4F [Also in Division G2] An optical scanner, e.g. for use with infra-red radiation comprises two concentric arrays of plane reflectors 12, 13 mounted to rotate about a common axis 15 and having their surfaces inclined to the axis in such manner to reflect beams radially from one array to the other, whereby an image formed by a fixed objective 21 is repeatedly scanned during the rotation by a fixed detector or eyepiece 16, the optical axes of the parts 21, 16 being parallel to the axis 15. The separation and angles of each pair of mirrors 12, 13 may be different so that contiguous areas of the field are scanned once per revolution. The surfaces 12, 13 may be at right angles, Figs. 3, 4 (not shown), and the surfaces 13 may be replaced by pairs of surfaces (24a, 24b), Figs. 5 to 8 (not shown), at right angles to one another forming roof mirrors. In a modification of the embodiment of Figs. 7, 8, see Fig. 11, the roof mirrors and the associated surface 12 are replaced by corner cube prisms 28 having three internal reflecting surfaces, folding mirrors 29 being interposed between the objective 21 and the prisms 28, which may be made of silicon or germanium. Display optics is provided at 36 from a stata semi-conductor lamp array 34 modulated by the detector array 16, through similar prisms 33 (of glass), and folding mirror 35. The reflectors in all the embodiments shown in Figs. 1 to 8, may be replaced by prisms. If the detector is a line array, its image moves in a parallel manner. (For Figures see next page.)