摘要 |
The light source comprises an evacuated container having walls, at least a portion of which consists of an outer glass layer (23, 23') which on at least a major part thereof is coated on the inside with a layer of phosphor (24, 24') forming a luminescent layer and a conductive layer (25, 25') forming an anode. The layer of phosphor (24, 24') is excited to luminescence by electron bombardment from a field emission cathode (40, 40') located in the interior of the container. A modulator electrode is arranged between the cathode (40, 40') and the anode (25, 25') for creating an electrical field necessary for the emission of electrons. The field emission cathode (40, 40') includes a longitudinally extending core (41, 41') having a central axis, and field emitting bodies (42, 42') extending from the core (41, 41'). The field emitting bodies (42, 42') are elongate and are distributed along at least a part of the length of the core (41, 41'). The field emitting bodies (42, 42') extend radially outwards from the core (41, 41') and have free ends provided with field emitting surfaces.
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