ES2353658T3 - PLASMA BULB WITH MEANS TO GENERATE AN ULTRASONIC RESONANT WAVE IN YOUR AMPOLLA. - Google Patents

Abstract

The lamp (40) has a quartz bulb (11) with an element of column of sulfur in the periodic classification table of chemical elements. A magnetron (14) generates and maintains a plasma in the bulb, and a stroboscopic source generates an ultrasonic resonant wave in the bulb. The bulb is enclosed in a Faraday cage that is formed of a metallic reflector closed by an electrical conductor. A window of the conductor is made of a transparent material sheet covered with a thin layer of electrically conducting material such as doped ceramics e.g. indium-tin-oxide (ITO) or fluorine-doped tin oxide (FTO).

Description

Plasma bulb with means to generate in your blister an ultrasonic resonant wave.

Technical field

The present invention relates to a bulb plasma comprising a quartz ampoule containing at least an element of the sulfur column in the leaderboard periodic of the chemical elements and means arranged to generate and maintain a plasma in this vial by sending electromagnetic waves of hyperfrequency in said blister.

Prior art

Between the bulbs with a good reproduction chromatic, discharge bulbs, fluorescent, halogen or even of metal halides, they all have a light efficiency far superior to that of incandescent bulbs. This is the reason why they have monopolized a large part of the market although contain toxic substances, specifically mercury in most of the cases. The risk of toxic waste on a large scale result of this is recognized as a first environmental threat importance. In the European Community, the devices containing mercury are subject to strict regulations aimed at limit them, even to ban them, effective from July 1, 2006 (EC Directive 2002/95 of the European Parliament and of the Council of January 27, 2003, Commission Decision of August 18, 2005, Commission Decision of October 13, 2005). In what refers to lighting systems, their progressive withdrawal from  market is carried out on condition that a technology of exempt replacement of toxic products. This legal provision generates, therefore, a potential market of considerable size.

A new lighting technology, exempt from pollutants, based on the light emission of diatomic vapors of certain elements of the column called VIA of the table of Mendeleïev, that is to say from the periodic table of the elements chemical, is developing in various countries such as Germany, South Korea, Japan, the Netherlands, Russia, Switzerland and The USA. The relaxation of the recomposed molecules after the dissociation produces an important light radiation. To one pressure of several bars, the emission spectrum extends from Continuously from 370 to 900 terahertz and its maximum is in The visible field Energy is provided by induction electromagnetic, usually with a magnetron that radiates at approximately 2.45 gigahertz, in order to avoid contact with the electrodes and thus prolong the life of the blister. Thus obtaining molecular dissociation by heating, the emission of a radiation of Planck in the infrared. The active substance, which condenses on cold, it is placed in a blister filled with a neutral gas. With the resonance, an electric shock is formed, which allows to evaporate the active substance Then, molecular plasma is formed luminescent. The higher its temperature, the greater its effectiveness light. The temperature resistance of the vial determines Therefore the effectiveness of the system. Therefore the blister is quartz molten. The first commercialized bulb, called SOLAR-1000 (US Patent 5,404,076), is equipped in addition to a device that keeps its blister in rotation at approximately 2500 t / min. The active substance used is sulfur or selenium. The light efficiency of this bulb exceeds 110 Lm / W at full power (1400 W). But, if the rotation of the blister is stops, its light efficiency decreases clearly. In absence of ventilation, the injected power must also be reduced by half in the case of sulfur, if not the blister melts. The observation indicates that the plasma's ability to absorb microwave increases with temperature, in any case up to a certain limit. This positive feedback carries an avalanche risk thermal An overheating bag may be formed that at coming into contact with the blister causes its breakage. Rotation of the ampoule allows to avoid this by stirring the plasma at high temperature by thermal convection, the centripetal acceleration being developed, in fact, far superior to gravitation in most of the blister, for the bulb SOLAR-1000.

However, this solution is too much limiting since the mechanical part decreases the relationship between shelf life and extra cost. Numerous publications describe inventions in order to alleviate this defect. However all large-scale commercial launches have failed until now. These technological advances are still not enough since that either the device still comprises a movement, for example, to force the passage of air around the blister, or the vial contains contaminant additives (US 6,157,141, DE 101.27.961 A1), or the blister is static and the electric field swivel (US 5,227,698, US 6,476,557 B2, US 6,476,557 B1, US 6,873,119 B2, US 5.36T226) although this polarized field is obtains on account of an increase in the complexity of the structure of the resonant cavity and the impossibility of placing the blister in the exterior of said cavity through a coupling electromagnetic. In addition, in known discharge bulbs, means are provided to avoid the resonance phenomena that tend  to detrimentally limit the lifespan of these light bulbs.

It is known, by the international publication WO 01/82332, a filament lighting device for a bulb without electrodes. The present invention, although based on the same type of bulb without electrodes as described in this publication, differs because this bulb does not use a wave resonant ultrasonic to influence the characteristics of the plasma, which therefore prevents rotation of the blister.

A bulb without electrodes is also described in the European publication EP 0 897 190. However, this bulb, although with a composition of the active medium of the same nature or of a different nature than that of the present invention, presents the peculiarity that its blister is cooled by a jet of air and that the plasma also stabilizes through its geometry. In the bulb of this invention the ampoule, which is shaped spherical or oblong in shape with a narrowing in the part central, it uses an acoustic resonance to maintain the stability of the electric shock, with the power supply through a high frequency source modulated

US 4 170 746 describes a light bulb electrodes with operating fields outside the bands of Acoustic resonance of mercury and halide vapor vapors metallic The present invention differs from the bulb object of This patent because it is without electrodes and because it works in the field of acoustic resonance, field in which this other bulb is unstable. This instability can lead to the destruction of the blister, if it is designed according to the characteristics stated in this patent.

US 5 136 170 uses a light bulb or UV source excited by electrodes located outside the blister and they use the principle of silent discharge. Be apply an alternative voltage that can have a frequency elevated to allow the transmission of energy through the dielectric layers. The present invention does not resort to this type of silent download, the coupling mode is different because of the use of a microwave cavity and, in addition, in this patent, no mentions the use of an acoustic resonance which, in turn, is favorable to discharge plasma stabilization electric

The invention object of the publication International WO 02/101790 refers to a bulb equipped with electrodes that receive an alternative voltage with a frequency less than or equal to 50 MHz and that uses an antenna with capacitive coupling located near the discharge zone. This antenna allows to stabilize the light discharge, but they are mandatory materials with high resistance temperatures, since the discharge is in contact with said dielectric antenna The bulb of the present invention uses a remote docking antenna, since there is no device in the vicinity of the discharge zone which favors therefore The stability of the electric arc. This antenna may be distant of the blister and, therefore, there are no problems of resistance to hot. On the other hand, in this publication, a source of high frequency located in megahertz to excite the discharge and the acoustic resonance described herein is not illustrated request.

Exhibition of the invention

The present invention aims to alleviate the drawbacks of known systems. More precisely, it refers to a bulb without electrodes that allows to avoid resorting to a mechanical movement without, however, needing additives, nor place the blister inside a resonant cavity.

To do this, the plasma bulb according to the invention, as defined in the preamble, is characterized because it also includes means arranged to generate a wave ultrasonic resonant in the bulb of said bulb from an ultrasonic vibration generated in the plasma, according to the claim 1.

Advantageously, said arranged means to generate electromagnetic waves and keep the plasma comprise  a magnetron.

Preferably, the magnetron is fed by a continuous high voltage supply connected to the sector electric.

In a first preferred embodiment of the bulb according to the invention, the means arranged to generate an ultrasonic vibration in the plasma and generate a resonant wave ultrasonic in the bulb of said bulb may comprise a passive resonant electrical circuit spliced between the magnetron and the continuous high voltage supply of said magnetron, said passive resonant circuit having at least a frequency of resonance between 15 kilohertz and 200 megahertz.

According to a variant of this embodiment, the means arranged to generate an ultrasonic vibration in the plasma and generate an ultrasonic resonant wave in the blister of said bulb may comprise an active modulator arranged to inject an electric oscillation, whose spectral power occupies the minus a band between 15 kilohertz and 200 megahertz, between magnetron and the continuous high voltage supply of said magnetron

Said modulator can be fed by the continuous high voltage supply of the magnetron by means of a resistance divider bridge, or feed directly by The electrical sector.

Preferably, said modulator is coupled to the high voltage between the magnetron and the high voltage supply continuous of said magnetron by means of a high transformer isolation. It can also be coupled through a branch capacitive high insulation.

According to another embodiment variant, the means ready to generate an ultrasonic vibration in the plasma and generate an ultrasonic resonant wave in the blister of said bulb can comprise an optocoupled switch arranged to introduce an electric oscillation, whose spectral power occupies at least one band between 15 kilohertz and 200 megahertz, between the magnetron and the continuous high voltage supply of said magnetron.

Preferably, the optocoupled switch is placed in series in a resonant shunt spliced between the magnetron and the continuous high voltage supply of said magnetron

According to yet another embodiment variant, the means arranged to generate an ultrasonic vibration in the plasma and generate an ultrasonic resonant wave in the blister of said bulb comprise a frequency elevator arranged to produce a radio frequency wave, connected to the electrical sector, and arranged between said electrical sector and a transformer of radio frequency booster that feeds said magnetron

According to another preferred embodiment of the plasma bulb, the means arranged to generate a ultrasonic vibration in the plasma and generate a resonant wave Ultrasonic in the bulb of said bulb comprise a source strobe whose whipping frequency is between 15 kilohertz and 200 megahertz.

Said strobe source is equipped advantageously a reflective or refractive collimation optic to focus its flow inside said blister, being said reflective or refractive collimation optics preferably integrated into the reflector of the bulb.

In an embodiment of the bulb plasma according to the invention, said ampoule is enclosed in a Faraday cage, said Faraday cage being formed by a reflector closed by an electric conductor, and the conductor electric comprises at least one window consisting of a sheet of transparent material covered by a thin layer of material electrically conductive

Brief description of the drawings

The present invention will be better understood in reference to the description of various embodiments and to the attached drawings in which:

Figure 1 represents a schematic view of a first embodiment of the plasma bulb according to the invention,

Figure 2 represents a schematic view of a first variant of the first embodiment as it is represented by figure 1,

Figure 3 represents a schematic view of a second variant of the first embodiment as it is represented by figure 1,

Figure 4 represents a schematic view of a third variant of the first embodiment as it is represented by figure 1,

Figure 5 represents a schematic view of a fourth variant of the first embodiment as it is represented by figure 1,

Figure 6 represents a schematic view of a fifth variant of the first embodiment as it is represented by figure 1,

Figure 7 represents a schematic view of a sixth variant of the first embodiment as it is represented by figure 1,

Figure 8 represents, in perspective sectioned, a second embodiment of the plasma bulb according to the invention,

Figures 9, 10 and 11 represent respectively in section and in projection the blister of a plasma bulb and

Figure 12 represents in a graph of the measurements of the spectral power of a bulb's radiation Sulfur plasma microwave, divided by power absorbed by the magnetron, for the bulb according to the mode of embodiment of figure 3, and in the case where the plasma is not modulated.

Way (s) of carrying out the invention

Referring to figure 1, the bulb 10 of plasma, according to a first embodiment of the invention, comprises a blister 11 and a high voltage supply 12 continuous (A.T.C), connected to electrical sector 13, and that it supplies a voltage that is high enough to power a magnetron 14. This is coupled to a resonator 15 of hyperfrequency The bulb 11 of the bulb 10 comprises a quartz rod 16, to hold it, which is mounted on a coupling system outside the resonator 15 of hyperfrequency Coupling of magnetron 14 to resonator 15 It is done using an iris or an antenna 17. The bulb 10 it comprises a reflector 18, specifically a metallic reflector, which surrounding the blister 11 and which is closed by a conductor 19 electric that lets light in at least one window consisting of a sheet of transparent material covered by a thin layer of electrically conductive material such as a doped ceramics, for example ITO or FTO. This provision forms a Faraday cage and its function is to prevent the leakage of the microwave radiation

A resonant passive circuit 20 of Radio frequency, of type LC for example, is inserted between the power 12 and magnetron 14. So, when circuit 20 Passive radio frequency resonant is excited by instability of magnetron 14, adds a wave to the continuous high voltage (A.T.C) electric, whose spectral power is mostly between 15 kilohertz and 200 megahertz, to form a high voltage modulated (A.T.M). The anode 14a of the magnetron 14 being connected to ground, the modulation must be spliced at cathode 14b of the magnetron 14, on the high voltage branch of the circuit. This arrangement forces to strongly isolate the modulator, which makes advantageous the use of a passive circuit in terms of building. In return, this solution does not allow control modulation The cathode 14b of the magnetron 14 is coupled to a heating circuit 21 that is fed by sector 13 electric through a first filter 22 antiparasitic. One second 23 anti-parasite filter is mounted, on the other hand, between sector 13 Electric and 12 high voltage power. A self-inductance 24 current stabilization is mounted between the power 12 high voltage and resonant passive circuit 20.

Referring to figure 2, the bulb 30 of represented plasma, which is a variant embodiment of the illustrated by the plasma bulb 10 of Figure 1, it comprises a certain number of components that are identical to those of the plasma bulb 10 and carrying the same numbers of reference. An active radiofrequency modulator 31 is inserted between feed 12 and magnetron 14 in order to add to the high voltage continues (A.T.C) an undulating component and form thus the high modulated voltage (A.T.M). Most of the energy of the wave produced by the radiofrequency modulator 31 is situated in one or several bands located between 15 kilohertz and 200 megahertz, determined by an oscillator 32, of the Hartley type by example. The modulator 31 is fed with low continuous voltage. This power is taken over high voltage by a bridge 34 divider, made with two resistors, respectively R1 and R2. A voltage regulator 33 is further inserted between bridge 34 divider and modulator 31.

The plasma bulb 40, illustrated by the Figure 3, is a variant embodiment of the bulbs 10 and 30 illustrated by figures 1 and 2, and comprises a certain number of components that are identical to those of these bulbs and that They carry the same reference numbers. In this embodiment, the ampoule 11 is disposed inside the resonator cavity 15 of hyperfrequency coupled to magnetron 14. In this variant, the radiofrequency modulator 31 is not put to the potential of high DC voltage (A.T.C), is fed by sector 13 electric. The modulator 31 is coupled to the high continuous voltage (A.T.C) by means of a 41 or 42 high isolation transformer placed either directly on the power line of the magnetron 14, or in a capacitive shunt 43. In this alternatively, a high value security resistor 44 may be added in parallel to the derivation. Be the transformer in a u another of positions 41 or 42, it may be helpful to add a parallel connection capacitor, respectively 45 or 46.

The plasma bulb 50, represented by Figure 4, which is a variant embodiment of the illustrated by means of figure 3, it comprises a certain number of components that they are identical to those of this bulb and they carry the same reference numbers In this variant, modulator 31 is coupled to continuous high voltage (A.T.C) by means of a self-inductance 51 of serial spliced low voltage coupling on the low part voltage of a capacitor 52 that forms a capacitive branch. Between the low voltage coupling self-inductance 51 and the capacitor 52 is injected radio frequency alternating current that feeds modulator 31. So that it passes through the line of high voltage, the product of the magnetron's dynamic resistance 14 due to capacitor capacity 52 must be greater than inverse of the modulation frequency.

Figures 5 and 6 represent respectively two variants of 60 and 70 plasma bulbs corresponding to the first embodiment of the invention. Notwithstanding certain components remain identical to the components of the variants described above and therefore carry the Same reference numbers. In these embodiments, the modulator 31, but continuous high voltage (A.T.C.) is interrupted by an optocoupled switch 61 controlled by an oscillator 32. This produces an electric wave whose energy is largely located between 15 kilohertz and 200 megahertz.

In the variant according to figure 5, all the high DC voltage (A.T.C) is interrupted, switch 61 optocoupler is placed in series downstream of the feed 12 high voltage continuous.

In the version illustrated by Figure 6, the optocoupled switch 61 is placed in series in a branch 71 resonant, an LC circuit for example, spliced downstream of the power supply 12. Only the high voltage part is interrupted continuous (A.T.C) that is extracted by a capacitive divider bridge  formed by two capacities, respectively 72 and 73. Preferably, a sparkmeter 74 is spliced in parallel with the capacitor 72 to protect it.

In the five variants illustrated by the Figures 1, 3, 4, 5 and 6, it may be useful to insert a serial self-inductance of current stabilization 24 at the output of 12 high voltage supply to stabilize the current fed. In the six embodiments according to figures 1 to 6, the modulated or interrupted high voltage (A.T.M) is connected to the cathode of magnetron 14 to feed it. 12 high feed  continuous voltage can comprise a trim regulation for Control the power of the bulb. In this case, it is preferable insert a 23 anti-parasite filter upstream of the feed 12.

Referring to Figure 7, the bulb 80 of represented plasma comprises a certain number of components that are identical to those of the bulbs described above and that They carry the same reference numbers. The bulb 80 comprises specifically a frequency elevator 81 that produces a wave of radiofrequency The amplifier of this frequency elevator 81, which is fed by the single phase electric sector 13, transfers most of the electrical power absorbed in a or several bands located between 15 kilohertz and 200 megahertz, determined by the radio frequency oscillator 32. Wave of radio frequency (R.F.) thus produced crosses a transformer 82 Radio frequency voltage booster to produce high radio frequency voltage (A.T.R.F.). This connects to the cathode of the magnetron 14. The voltage is high enough to power the magnetron 14 after being semi-rectified by a diode 83 of high voltage radiofrequency. The frequency elevator 81 can understand a trim regulation to control the power of the light bulb. In this case, it is preferable to insert a filter 23 antiparasitic upstream of the frequency elevator 81.

In all the variants described above, the electromagnetic microwave flow injected by the magnetron 14 in the hyperfrequency resonator 15 it is interrupted or modulated with object of generating an ultrasonic vibration of the plasma, which generates an ultrasonic resonant wave in ampoule 11. If the cathode 14b of the magnetron 14 needs a heating 21, a filter 22 antiparasitic is preferably spliced upstream of it to avoid parasitizing the electrical sector 13.

Figure 8 illustrates a second mode of embodiment of the plasma bulb according to the invention which is independent of the generator power supply of the electromagnetic waves. In this case, the plasma bulb 90 comprises an auxiliary strobe source 91 of optical radiation directed to blister 11. Then magnetron 14 can feed by a simple high voltage supply 12 continues, obtaining the ultrasonic vibration of the plasma by absorption of radiation emitted by strobe source 91. This is constituted by a discharge vial or by one or several LED or LASER diodes powered by a 92 power supply impulses, whose spectral power occupies at least one band approximately between 15 kilohertz and 200 megahertz, determined by oscillator 32. Preferably, strobe source 91 it is equipped with a reflective or refractive collimation optics 93 94 that focuses its flow inside the ampoule 11. Preferably, this optics is integrated into the reflector of the luminaire 18.

Figures 9, 10 and 11 illustrate the vial 11 of a plasma bulb that is, as described in reference to figure 8, independent of the power supply of the generator of electromagnetic waves. In this variant, the plasma is self-oscillating and it is not necessary to modulate the flow of energy that allows it to be maintained. Ultrasonic plasma vibration is obtained using a blister 11 with two volumes 11a and 11b identical radio R communicators. This quartz blister 11 is disposes at the end of the quartz rod 16. A collar 110 Quartz is welded around the neck or channel 112 arranged between the two volumes 11a and 11b, said neck having preferably a width less than or equal to three quarters of the radius R of volumes 11a and 11b. The collar 110 is covered by a thin layer of ceramic, for example aluminum oxide, allowing to reduce the optical coupling between the two volumes 11a and 11b. These are preferably symmetrical with each other and the length of the passage channel 112 from one volume to the other is chosen a slightly lower than its average radius (R) so that there is a constructive interference between the acoustic vibrations that they develop in one and the other of volumes 11a and 11b in resonance. With volumes 11a and 11b of a centimeter of medium diameter, the resonance frequency is set at approximately 50 kilohertz in the case where the active substance is sulfur.

Figure 12 is a graph representing the radiation spectral power of a microwave bulb sulfur plasma, divided by the power absorbed by the magnetron For these tests, a model magnetron has been used Panasonic 2M244-M1. The measurements have been made in steady state for an absorbed power of 660 W including cathode heating. The ampoule used is spherical, its interior volume is 11 cm3 and is filled with sulfur at 1.47 mg / cm3. In addition, it is static and works in absence of any forced cooling. The spectrum 121 is gets without forcing the ultrasonic vibration of the plasma. Its power spectral is maximum at approximately 680 THz (wavelength at the air at 440 nm), the light is therefore bluish. The spectrum 122 is obtained with the device according to the first embodiment of the  invention described in reference to figure 3, therefore, with the same blister Its spectral power is maximum at 581 THz (length wave in the air at 516 nm), the light is white. Curve 123 represents the function of spectral relative light efficiency in photopic vision, as defined by the International Commission of Illumination (CIE), multiplied by the maximum spectrum obtained with the device 122 according to the invention. It is observed that the spectral offset approximates the maximum emission of the eye sensitivity The device according to the invention increases the light efficiency of 41 to 84 Lm / W, attributing the consumption of energy to the magnetron terminals. The reproduction rate color defined by the CIE goes from 89 to 81. The bulb by both is suitable for the most diverse jobs, both indoors as outdoors.

Whatever the mode of realization of the bulb according to the invention, the ultrasonic plasma vibration generates an ultrasonic resonant wave in the blister, which generates The following phenomena:

- Plasma expansion. Gravitation no longer prints virtually no effect on the shape of the plasma and this one It extends to most of the volume of the blister. So, the blister excitation is uniformized, which is favorable for the luminaire efficiency.

- High temperature plasma agitation. By this, the acoustic wave raises the temperature threshold to from which the thermal avalanche appears.

- Spectral offset of the optical emission. He spectral offset comes from the fact that the optical emission is due to return of biatomic molecules of a certain electronic state excited to the fundamental electronic level and that each level of electronic energy is a function other than distance interatomic In the present case, the deviation between the two electronic levels is a decreasing function of energy Vibratory diatomic molecules. According to the principle of Franck-Condon, the vibratory energy does not change during a transition The energy of the photon, which is equal to the jump of electronic energy, therefore decreases with energy Vibratory molecules. Now the wave absorption acoustics in a gas is the fact of vibration excitation in polyatomic molecules. Therefore, by virtue of the foregoing, the sound wave absorption delays the optical emission in the decreasing sense of photon energy, that is, in the decreasing sense of frequency.

- Increase in thermodynamic performance of plasma, which is the ratio of optical radiation to flow of absorbed microwave energy, and therefore increase also of the light efficiency of the bulb. The effect of this phenomenon is visible in the measurements represented in figure 12. Knowing that the magnetron yield was 70%, it is verified that the thermodynamic performance goes from 41% to 63% thanks to the device according to the invention. This phenomenon is linked to the fact that the relaxation of vibrations in a polyatomic molecule it is clearly slower than the relaxation of the other modes of internal energy, rotation and translation. The time of Vibrational relaxation is of the order of 10 microseconds. So, when the period of the acoustic resonant wave is close to this value, acoustic absorption introduces a significant lag of the vibratory energy of the molecules, that is, a deviation between their effective energy level and what they would have in balance local thermodynamic The sound absorption is maximum in the phase opposition, as well as the speed of energy variation internal diatomic molecules in the blister. It is a increase in molecular dissociation, state doubling electronic excited and therefore also the production of optical photons

- Acoustic confinement of plasma. A sunset in acoustic resonance of the blister can generate impulses of stronger temperature in the core of the plasma than in the periphery, in the layers in contact with the blister. The energy reflected in the walls converge, in effect, in the center of the blister. So, the resonance accentuates the thermal modulation of plasma in its nucleus.

Claims (17)

1. Plasma bulb comprising a quartz vial (11) filled with at least one element of the sulfur column of the periodic classification table of the chemical elements and means arranged to generate and maintain a plasma in this vial by sending of electromagnetic hyperfrequency waves in said ampoule (11), characterized in that it further comprises means arranged to generate an ultrasonic resonant wave in the bulb (11) of said bulb from an ultrasonic vibration generated in the plasma, in which said means intended the creation of an ultrasonic resonant wave in said ampoule (11) does not comprise a blister (11) provided with two identical communicating volumes (11a, 11b) connected by a channel. 2. Plasma bulb according to claim 1, characterized in that said means arranged to generate electromagnetic waves and maintain the plasma comprise a magnetron (14). 3. Plasma bulb according to claim 2, characterized in that the magnetron (14) is powered by a continuous high voltage supply (12) connected to the electrical sector (13). 4. Plasma bulb according to claims 2 to 3, characterized in that the means arranged to generate an ultrasonic vibration in the plasma and generate an ultrasonic resonant wave in the bulb (11) of said bulb comprise a passive resonant passive electrical circuit (20) between the magnetron (14) and the continuous high voltage supply (12) of said magnetron (14). 5. Plasma bulb according to claim 4, characterized in that said passive resonant circuit (20) has at least a resonance frequency between 15 kilohertz and 200 megahertz. 6. Plasma bulb according to claims 2 to 3, characterized in that the means arranged to generate an ultrasonic vibration in the plasma and generate an ultrasonic resonant wave in the bulb (11) of said bulb comprise an active modulator (31) arranged to inject an electric oscillation, whose spectral power occupies at least a band between 15 kilohertz and 200 megahertz, between the magnetron (14) and the continuous high voltage supply (12) of said magnetron (14). 7. Plasma bulb according to claim 6, characterized in that said modulator (31) is fed by the continuous high voltage supply (12) of the magnetron (14) by means of a bridge (34) resistor divider. 8. Plasma bulb according to claim 6, characterized in that said modulator (31) is fed directly by the electrical sector (13). 9. Plasma bulb according to claim 6, characterized in that said modulator (31) is coupled to the high voltage between the magnetron (14) and the continuous high voltage supply (12) of said magnetron by means of a transformer (41) High insulation 10. Plasma bulb according to claim 6, characterized in that the modulator (31) is coupled to the high voltage between the magnetron (14) and the continuous high voltage supply (12) of said magnetron by means of a shunt (52) capacitive high insulation. 11. Plasma bulb according to claims 2 to 3, characterized in that the means arranged to generate an ultrasonic vibration in the plasma and generate an ultrasonic resonant wave in the bulb (11) of said bulb comprise an optocoupled switch (61) arranged to introduce an electric oscillation, whose spectral power occupies at least a band between 15 kilohertz and 200 megahertz, between the magnetron (14) and the continuous high voltage supply (12) of said magnetron (14). 12. Plasma bulb according to claim 11, characterized in that the optocoupled switch (61) is placed in series in a resonant shunt (71) spliced between the magnetron (14) and the continuous high voltage supply (12) of said magnetron. 13. Plasma bulb according to claim 3, characterized in that the means arranged to generate an ultrasonic vibration in the plasma and generate an ultrasonic resonant wave in the bulb (11) of said bulb comprise a frequency elevator (81) arranged to produce a radio frequency wave, connected to the electrical sector (13), and disposed between said electrical sector (13) and a voltage boosting radiofrequency transformer (82) that feeds said magnetron (14). 14. Plasma bulb according to claims 1 to 3, characterized in that the means arranged to generate an ultrasonic vibration in the plasma and generate an ultrasonic resonant wave in the bulb (11) of said bulb comprise a strobe source (91) whose frequency of Paddling is between 15 kilohertz and 200 megahertz. 15. Plasma bulb according to claim 14, characterized in that said strobe source (91) is provided with a reflective collimation optics (93) or refractive (94) to focus its flow inside said ampoule (11). 16. Plasma bulb according to claim 15, characterized in that said reflective (93) or refractive collimation optics (94) is integrated in the reflector (18) of the bulb. 17. Plasma bulb according to claim 1, characterized in that said ampoule (11) is enclosed in a Faraday cage, said Faraday cage being formed by a reflector (18) closed by an electric conductor (19), and because the conductor (19) electrical comprises at least one window consisting of a sheet of transparent material covered by a thin layer of electrically conductive material.