Thorn Emi Plc

John C White

John G Holden

Len Giddens

A luminaire is disclosed comprising a fluorescent plastics outer sleeve having a configuration such that a high proportion of the fluorescent light generated within the sleeve is emitted as visible light. The sleeve includes a fluorescent dye, which dye is excited by a blue phosphor discharge.

Light sources

An infra red radiation modulator comprises a p type silicon substrate 1 having spaced n type and p type doped regions 2, 3 having respective doping concentrations of approximately 10.sup.20 and 10.sup.16 /cm.sup.3. A signal source 11 provides a bias voltage between the doped regions 2,3 via electrodes 4 for modifying the concentration of free carriers in the substrate between the doped regions and therefore the response of the modulator to incident infra red radiation. By appropriate control of the bias voltage the modulator can be caused to modulate, chop, filter or spectrally scan the incident radiation.

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Cuddesdon, United Kingdom

John C White