Farran Technology Limited

Alan H Lettington

Brenda Lettington, Legal Representative

A scanning apparatus operable in the microwave, mm-wave, sub mm-wave (Terahertz) and infrared ranges comprises a primary drum () mounted for rotation about a central axis A of the primary drum being hollow and of rectangular polygonal form to provide a number of sides or facets () each adapted to transmit such radiation, from a field of view, which is plane polarized in a first direction at 45&#xb0; with respect to the rotary axis of the drum and to reflect radiation which is plane polarized in an orthogonal direction. Thus, radiation passing into the drum though whichever said side of the drum is currently facing the field of view and passing towards the diametrically opposite side will be plane polarized with a polarization direction such as to be reflected back by that diametrically opposite side towards the rotary axis of the drum. Each polygon side of the drum is configured so as to act, when reflecting radiation striking that side from within the drum, as a concave mirror, to focus the radiation towards a receiver assembly which includes a radiation detector for such radiation. In another embodiment scanning apparatus operable in the microwave, sub mm-wave, mm-wave and infrared ranges may comprise a reflective disc or mirror () mounted for rotation relative in a support () is itself mounted for rotation with respect to a second support () about a second axis inclined with respect to the first axis.

Scanning apparatus for scanning electromagnetic radiation

Scanning apparatus operable in the microwave, mm-wave and infrared ranges and comprises a support structure, a first reflective disc or mirror () which is mounted in said support structure for rotation relative to the support structure about a first axis (), and a second reflective disc or mirror () which is mounted in said support structure for rotation relative to the support structure about a second axis () and driving means for said discs or mirrors arranged to drive these in respective opposite senses. In operation of the apparatus, radiation from a scene being scanned reaching a reflective surface of the first disc or mirror is reflected thereby onto a reflective surface of the second disc or mirror, to be reflected by the latter, in turn, onto the reflective surface of the first disc or mirror again, to be reflected from the first disc or mirror into or onto a further part of the apparatus incorporating a receiver or receivers for such radiation. The reflective surface of the first disc or mirror has an axis of rotational symmetry, tilted at a first small angle relative to said first axis and the reflective surface of the second disc or mirror has an axis of rotational symmetry tilted at a second angle relative to said second axis. The driving means for the discs or mirrors is arranged to drive these in such a way as to effect a substantially linear scan. the size of said second angle relative to said first angle being selected so as to reduce or eliminate pupil wander in the direction orthogonal to the direction of line scan.

Scanning apparatus

Scanning apparatus operable for radiaton comprises a hollow polygonal primary drum rotatable about a central axis to present a plurality of internally presented sides or facets capable of reflecting the radiation concerned. A fixed Mangin mirror mounted within the primary drum directs such radiation onto the internally presented sides or facets of the primary drum to be reflected therefrom onto a rotating reflective faceted secondary drum. The secondary drum reflects the radiation onto a radiation receiver or sensor. The secondary drum is arranged to be rotated about an axis parallel with the rotary axis of the primary drum, in synchronism with the latter, in such a way that, over each line scanning period, radiation from substantially all of the respective facet of the primary drum can reach the receiver or sensor via the secondary drum.

Growing community of inventors

Berkshire, United Kingdom

Alan H Lettington