Abstract: To provide a uniformly illuminated panel of essentially uniform brightness hroughout, although illuminated by essentially point source lamps, a box-like structural element (1) is provided having a light emitting surface (2) which has, in the direction of transmission of radiation therethrough, a ratio of reflection to transmission of radiation greater than 50%, and preferably between 80% to 95%, the interior wall surfaces of the hollow structure being reflective, and the hollow structure having a depth dimension, for example about 2 cm, which is small with respect to the height and width dimensions.

Abstract: A fluorescent lamp control circuit which provides power at high frequency, or example in the order of 35 kHz, includes a push-pull oscillator circuit having two transistors (T1, T2), an inductance element (L1, L1'), and a capacitor (C1, C1') to supply the lamps (3, 3'). To prevent dangerous high voltages upon removal of the lamp load, connected to the oscillatory circuit and to the series resonance circuit, upon removal of failure of a lamp, a protective circuit is provided formed by a thyristor (TH) connected to short-circuit at least one of the transistors (T1) of the oscillatory circuit.