Abstract: An electrodeless fluorescent lamp comprises a closed-loop (“tokamak”) envelope, two ferrite cores, and an induction coil that is disposed on the envelope walls inside the closed-loop formed by the envelope. The envelope comprises two straight tubes of the same diameter. All coils' turns have essential the same length and are parallel to each other and to the closed-loop axis. Each ferrite core encircles a segment of each the coil's turn and one connecting tube. The lamp can be operated at driving frequencies of 100-600 kHz and lamp powers of 50-250 W. The ferrite core power losses were 6-8 W when the lamp was operated at a frequency of 200-300 kHz and lamp power of 140-150 W. The lamp light output was 12,500 lumen and luminous efficacy was 87 LPW.

Abstract: An electrodeless compact fluorescent lamp operated at a frequency from 50 KHz to 1000 KHz and RF power from 10 W to 40 W is described. The lamp includes a bulbous glass envelope (1) filled with rare gas and metal vapor, reentrant glass cavity (2), an induction coil (6) made from Litz wire, a ferrite assembly comprising a ferrite core (7) and MnZn ferrite disk (11), a cooling structure comprising a metal (or ceramic) tube (8) positioned inside the ferrite core (7) and a metal (or ceramic) unit (9) that transmits the heat from the cavity and ferrite assembly to the Edison socket (10), a thermal shield (12), and a driver and matching network located inside the lamp base (13). A protective coating (15) and phosphor coating (16) are coated on the inner surface of the envelope (1) and reentrant cavity (2). The reflective coating (17) made from alumina is coated on the inner surface of the cavity (2) and on the outer surface of the envelope bottom (4).

Abstract: In a conventional electrodeless discharge lamp, a large amount of magnetic field leaks from at light-transparent envelope, and the efficiency of conversion from electric power to light energy is low. In a electrodeless discharge lamp in which light-emitting gases in a light-transparent envelope are excited with a magnetic field generated from a coil, end portions of a magnetic material included in the coil are substantially axially disposed in the light-transparent envelope. As a result, the magnetic flux which leaks outside the light-transparent envelope is decreased so the density of the magnetic flux in the envelope is increased and the efficiency of the lamp is improved.

Abstract: An electrodeless fluorescent lamp operating at relatively low frequencies (50-500 kHz) whereby a ferrite core is utilized to generate the necessary magnetic and electric fields to maintain the discharge where the core material is Mn—Zn type combination due to its low power losses, 400 mW/cm3, in the frequency range of 50-100 kHz and magnetic field strengths of 150 mT. Furthermore, the material may cover a variety of atomic percentages of Mn and Zn added to Fe2O3 base to obtain favorable grain boundary and crystalline structure, resulting in a practical ferrite core material, having a Curie temperature greater than 200° C. Such material enables the operation of electrodeless fluorescent lamps with powers ranging from 10 W to about 250 W at low frequencies, as mentioned above, in such a manner that ferrite core losses constitute less than 20% of the lamp power and heat generated by core losses is minimized.

Abstract: An electrodeless fluorescent lamp employs a glass envelope made from a single linear tube filled with inert gas and mercury vapor. Phosphor and protective coatings are disposed on the inner surface of the envelope walls. An induction coil of few turns made from silver coated copper or Litz wire is wrapped around the linear tube in its axial direction. The inductively-coupled axially uniform plasma is generated inside the linear tube. The discharge electric field and current form a closed-loop path inside a tube in its axial direction. The lamp is operated at frequencies from 100 KHz to 100 MHz and RF power from 10 W to 2000 W (dependent on lamp size and number of turns). The lamp power efficiency and efficacy are comparable to those in electrodeless lamps of closed-loop shape operated with and without ferrite core.

Abstract: An electrodeless fluorescent lamp comprises a glass closed-loop envelope filled with inert gas and mercury vapor at pressure of 0.1-5 torr. An induction coil of few turns and made from Litz wire is disposed on the outer surface of the lamp inside of the closed-loop envelope. A phosphor coating is disposed on the inner surface of the envelope surface and a reflective coating is disposed on the inner surface of the area adjacent to the induction coil.

Abstract: An electrodeless inductively-coupled fluorescent lamp which operates at radio frequencies and contains an induction coil (1) which is inserted in a reentrant cavity (2) of the envelope (7) and is spread along the length of the reentrant cavity (2). The coil (1) is disposed within a cylinder (14) of thermally conductive metal. The use of the spread coil provides for reduction of starting and operation voltages of the lamp and results in lowering of the energy of ions bombarding the inner surface of the envelope (7) and the cavity (2) and therefore improves lamp maintenance and increases lamp life.

Abstract: An electrodeless lamp includes an envelope (1) containing a fill of discharge gas, a magnetic core (7), an induction coil (6) wound around the magnetic core (7), a driver circuit for supplying an electric current to the induction coil (6) to operate the electrodeless lamp, a socket (10) for receiving electrical power supplied to the electrodeless lamp, and a heat conduction means (8,9,8,9) thermally coupled to the magnetic core (7) for conducting heat generated in the magnetic core (7) to the ambient atmosphere to dissipate heat therein, or coupled to the socket (10) for conducting heat generated in the magnetic core (7) to the socket to dissipate heat therethrough.

Abstract: An electrodeless fluorescent lamp and fixture which operates at the frequency range of 50-1000 KHz and power from 20 to 200 W is disclosed. The lamp includes a bulbous envelope (1) filled with rare gas and metal vapor and a reentrant cavity (5). The inner walls of the envelope are coated with phosphor (2) and a protective coating (3). An induction coil (9), made from multiple strands of wire having very low resistance at frequencies below 1000 KHz, together with a ferrite core (10), having high permeability and low power losses, generates an inductively-coupled plasma in the envelope volume. The plasma generates visible and UV radiation that is converted into visible light by the phosphor coated on the envelope walls. A metallic cylinder (13), placed inside the ferrite core (10), removes the heat generated by the plasma from the coil and ferrite core and redirects the heat to the lamp base and thence to the lamp fixture.

Abstract: This invention relates to electrodeless fluorescent RF lamp which includes bulbous lamp envelope (10, 20) with a top, a bottom and a fill of rare gas and vaporizable amalgam (14) therein. A reentrant cavity (11, 21) is disposed adjacent the bottom of the envelope (10 a, 20a) and at least one tubulation (12, 22) extends from the envelope to hold at least a portion of the vaporizable amalgam. An induction coil (2) is disposed on lead wires and coupled with a radio frequency excitation generator for generation of a plasma to produce radiation. At least the major portion of the cold spot where the amalgam resides is maintained at a temperature between about 60.degree. and 140.degree. C. during operation of the lamp, by utilizing a portion of the induction coil to warm up to amalgam.

Abstract: An electrodeless fluorescent lamp and fixture is disclosed which operates at radio frequencies and contains a bifilar coil to reduce RF voltage between the plasma and the coil and a metallic cylinder (10) to remove heat from a said bifilar coil. The bifilar coil consists of two windings. The primary (induction) winding (6) is used to generate RF electrical azimuthal field in the bulb volume needed to maintain the inductively-coupled RF plasma. The second (bifilar) winding (18) has essentially the same number of turns and is wound on the inductive winding (6), but in the direction opposite to that of the primary (inductive) winding. The RF current flowing in the inductive winding (6) induces an RF voltage of the opposite polarity in the bifilar winding (18), so two adjacent turns of both windings have equal (or nearly equal) but of opposite sign RF potentials with respect to the plasma.

Abstract: An electrodeless inductively-coupled fluorescent lamp which operates at ro frequency comprising a bulbous envelope (1) filled with rare gas and metal vapor. A reentrant cavity (4) and an induction coil (6) are disposed in the cavity (4). The inner walls of the envelope (1) and the cavity (4) have a protective coating (3) and a phosphor coating (2). A metal Faraday cylinder (12) welded to the lamp base (13) is disposed between the cavity (4) and the coil (6) to reduce capacitive RF voltage between the coil and the plasma to improve lamp maintenance and remove heat. A tubulation (16) is disposed on the lamp axis to evacuate the envelope (1). The proximal end of the tubulation (16) has an expansion (20) with the volume (23) where the initial capacitive discharge is ignited.

Abstract: An electrodeless fluorescent lamp containing a fill of a rare gas and mercury and a flag (14) disposed therein at a predetermined location in the lamp for increasing the rate of luminous development in the lamp. The flag (14) includes a pair of spaced-apart metallic foil sections (31) and a metallic mesh substrate (30) disposed between the foil sections (31) whereby to be shielded from ion bombardment of the discharge. A coating (30a) of indium which is adapted to amalgamate with the mercury is disposed on the mesh (30). The sections are joined together by spot-welding (32) to enable migration of mercury into and out of the space between the sections thereby enable the atoms to form an amalgam with the indium and be rapidly released therefrom.

Abstract: An electrodeless fluorescent lamp and fixture is disclosed which operates radio frequencies and contains a metallic cylinder 9 to suppress capacitive coupling between an induction coil 7 and a plasma in the envelope 1 of the lamp and simultaneously substantially reduce heat in a reentrant cavity 5. The lamp includes a bulbous envelope 1 having a conventional phosphor layer 3 disposed therein. The bulbous envelope 1 contains a suitable ionizable gaseous fill. Upon ionization of the gaseous fill, the phosphor is stimulated to emit visible radiation upon absorption of ultraviolet radiation. The reentrant cavity 5 of the bulbous envelope 1 contains an inducation coil. The cylinder 9 transfers heat from the plasma to the fixture 11 through a base 13, 13a on the envelope 1.

Abstract: Electrodeless, low pressure, fluorescent discharge lamp of high aspect ratio, with a substantially flat spiral rf coil adjacent a back face (and insulated therefrom), that emits light through a front surface or selected portions under control of internal reflective and phosphor coatings placement to afford minimum resonance trapping, high efficiency and uniform illumination of high specific intensity over a selected area of the front wall.

Abstract: Electron cyclotron resonance (ECR) is achieved in a source chamber of a size which is non-resonant with respect to propagation of the microwave power within the chamber. The microwaves are delivered into the chamber via a waveguide and window so that breakdown occurs initially only in a region in the vicinity of the window. A dielectric coupler between the waveguide and the window has a larger end and a smaller end and is filled with a dielectric material. The magnetic field generator for stimulation the electron resonance in the chamber includes a pair of conductive current carrying coils coaxial with each other and with an axis of the chamber, the coils being arranged in a Helmholtz configuration. The waveguide includes a microwave stub tuner for tuning the propagation and absorption of the microwave power in the plasma within the chamber to control the location and shape of the region in which the plasma is formed.