Abstract: The general field of the invention is that of devices for controlling luminance of lighting devices comprising light-emitting diodes. The control device is driven by a cyclic input signal of determined period, each period comprising an activation time representative of a determined luminance level. The control device comprises analog electronic means generating a second control signal for the intensity of the electric current passing through the light-emitting diodes, the amplitude of the second control signal being an increasing function of the activation time in such a way that the combination of the cyclic input signal and of the second signal applied to the light-emitting diodes gives a greater luminance range than the range of the cyclic input signal.

Abstract: The general field of the invention is that of devices for controlling luminance of lighting devices comprising light-emitting diodes. The control device is driven by a cyclic input signal of determined period, each period comprising an activation time representative of a determined luminance level. The control device comprises analogue electronic means generating a second control signal for the intensity of the electric current passing through the light-emitting diodes, the amplitude of the second control signal being an increasing function of the activation time in such a way that the combination of the cyclic input signal and of the second signal applied to the light-emitting diodes gives a greater luminance range than the range of the cyclic input signal.

Abstract: The field of the invention is mainly that of light boxes used for the illumination of display screens using optical valves, notably for liquid crystal matrix displays also known as LCD screens. The light sources used are generally fluorescent tubes powered with a high voltage by devices comprising Royer electronic oscillators. These electronic oscillators do not allow wide dynamic ranges of luminance, which can be necessary for certain applications, to be easily attained. The oscillator according to the invention comprises an electronic device for discharging the stored electrical energy, said discharge device being controlled by an electronic control device using chopping modulation, thus enabling wide dynamic ranges of luminance to be attained.

Abstract: The field of the invention is that of light boxes used for illuminating optical-valve displays, especially matrix liquid-crystal displays (or LCDs). The illumination from light boxes can at the present time be produced by light-emitting diodes that emit in various spectral bands so as to reconstruct white illumination. For a number of applications, in particular aeronautical applications, it is necessary to maintain the photometric and colorimetric characteristics of this illumination independently of the environmental and ageing conditions of the components. The invention provides an electronic feedback control device for maintaining the photometric and colorimetric characteristics of this illumination at given setpoint values without introducing disturbing optoelectronic devices into the light box. Several possible technical solutions are described.

Abstract: The field of the invention is mainly that of light boxes used for the illumination of display screens using optical valves, notably for liquid crystal matrix displays also known as LCD screens. The light sources used are generally fluorescent tubes powered with a high voltage by devices comprising Royer electronic oscillators. These electronic oscillators do not allow wide dynamic ranges of luminance, which can be necessary for certain applications, to be easily attained. The oscillator according to the invention comprises an electronic device for discharging the stored electrical energy, said discharge device being controlled by an electronic control device using chopping modulation, thus enabling wide dynamic ranges of luminance to be attained.

Abstract: The field of the invention is that of light boxes used for illuminating optical-valve displays, especially matrix liquid-crystal displays (or LCDs). The illumination from light boxes can at the present time be produced by light-emitting diodes that emit in various spectral bands so as to reconstruct white illumination. For a number of applications, in particular aeronautical applications, it is necessary to maintain the photometric and calorimetric characteristics of this illumination independently of the environmental and ageing conditions of the components. The invention provides an electronic feedback control device for maintaining the photometric and calorimetric characteristics of this illumination at given setpoint values without introducing disturbing optoelectronic devices into the light box. Several possible technical solutions are described.

Abstract: An electronic device for multiplexing several loads to the terminals of a source of alternating electrical energy. The source(4) of alternating electrical energy is coupled by electromagnetic flux to the loads by using primary excitation windings 71, 81 and 91 connect to the terminals of the source (4) of alternating electrical energy and secondary windings respectively corresponding to the number of loads. The secondary windings are at least partially coupled to the primary winding and are each connected to the terminals of a load. The coupling is inhibited by auxiliary winding 73 which are each totally coupled with the secondary winding 72. The inhibition function is controlled in order to inhibit all the magnetic couplings except for one and this particular one changes as a function of the respective load to be coupled to the source 4 of alternating electrical energy.