Illumination method and device
OwnerLeslie Adrian Alfred Woolardinventor
Life of this patent
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Abstract
A method for furnishing a perceptor with apparently continuous illumination over an extended target area, in which at any instant only part of said area is illuminated, but every part thereof is intermittently and repeatedly illuminated by discontinuous flashes. With regard to any one part of said target area, the flashes are repeated at time intervals not less than the decay period of the response elicited in the perceptor. The method is performed by means of a device which comprises a beam-generating arrangement (1) that focuses a beam of radiation (5) upon a rotatably-mounted light-deflector (6), which is rotated under control at a suitably high speed by mechanical means (9, 10, 11 and 12) so as repeatedly to illuminate a target area (15) with a narrow flash to radiation (16).
Claims10
A method of furnishing a perceptor with apparently-continuous illumination by electromagnetic radiation to which the perceptor is responsive over an extended target area, in which a rotatable double-sided reflector is used to deflect a relatively narrow beam of substantially parallel radiation incident thereon substantially normal to its axis of rotation from one point to another over a relatively wide target area, whereby at any instant only part of said area is illuminated with said radiation but every part thereof is intermittently and repeatedly illuminated by discontinuous flashes of said radiation, said flashes being as regards any one part of said target area repeated at time intervals not less than the decay-period of the response of the perceptor to that radiation.
A light disseminator which comprises means operable to direct a beam of substantially parallel light so that said light impinges upon a rotatably-mounted double-sided light-deflector substantially normal to said light-deflector's axis of rotation, said light-deflector being arranged and disposed so that dependent upon the rotational position of said light-deflector, said light-deflector will deflect the light-beam to one point or another around an arcuate target area centred upon the rotatable deflector, and means operable to rotate the light-deflector so that said light-deflector sweeps the deflected beam around said arcuate target area at such a rotational rate that any given part of the arcuate target area is intermittently but repeatedly illuminated by discontinuous flashes of light provided by the deflected light-beam at time-intervals of not more than one tenth of a second.
Dependencies are inferred from the claim text.