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Matsushita Electric Works Research and Development Laboratories Inc

Matsushita Electric Works, Ltd.

Matsushita Electric Works Research & Development Labratory

Matsushita Electric Works R&d Laboratory, Inc.

Matsushita Electric Works Research and Development Laboratory Inc

Matsushita Research and Development Laboratories Inc

Matsushita Electric Works R & D Laboratories Inc.

Matsushita Electric Works Research and Development Labs Inc.

Matsoshita Electric Works Research and Development Laboratory Inc

Matsushita Electric Works Research and Development Laboraty Inc.

Oleg A Popov

Jakob Maya

Robert T Chandler

Edward K Shapiro

Jagannathan Ravi

Mamoru Takeda

Toshiaki Kurachi

Kouji Miyazaki

Shinichi Anami

Young-Jae Cho

Pradeep Kumar Nandam

Shingo Matsumoto

Koichi Kobayashi

An electrodeless lamp includes a bulbous lamp envelope enclosing an inert gas and a vaporizable metal fill, the lamp envelope having a reentrant cavity and an envelope bottom, an electromagnetic coupler positioned within the reentrant cavity, and a thermal shield positioned in proximity to the envelope bottom and configured to increase the temperature of the envelope bottom. By increasing the temperature of the envelope bottom, a cold spot is prevented. As a result, light output at low temperatures is comparable to light output at room temperature.

Electrodeless fluorescent lamp with stabilized operation at high and low ambient temperatures

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

Electrodeless lamp

An electrodeless low pressure discharge lamp comprises an envelope made from a straight tube and a reentry cavity sealed to one of tube's ends. The cavity has several hollow ferrite cores separated from each other with a few mm distance. Each ferrite core has an induction coil of few turns wound around the core. Each cavity has a cooling copper tube or rod located inside the ferrite core that removes heat from the cores and dumps the heat into a heat sink welded to the cooling tube/rod thereby keep the temperature of the ferrite cores below their Curie point. Each induction coil is electrically connected to the matching network while all matching networks are connected in parallel to the high frequency power source (driver). Inductively coupled plasmas generated in the envelope by several core/coil assemblies produce axially uniform UV and visible radiation.

Electrodeless low pressure lamp with multiple ferrite cores and coils

The present invention comprises a compact electrodeless fluorescent lamp that includes a transparent envelope containing a fill of inert gas along with a vaporizable metal such as mercury. An induction coil is operated by a driver circuit, and is positioned inside of a reentrant cavity in the envelope with an adjacent permeable magnetic field manipulation structure having a shunting surface ending at a shunting surface periphery. A thermally and electrically conductive primary cooling structure is positioned adjacent the magnetic field manipulation structure to extend within the shunting surface periphery while being separated from the induction coil thereby. A further component cooling structure is provided to at least partially enclose the driver circuit connected to the induction coil.

Compact electrodeless fluorescent lamp with improved cooling

An electrodeless fluorescent lamp employs a glass envelope made from a single linear tube or bulb and a reentry cavity disposed on the envelope axis and sealed to the envelope. The envelope is filled with inert gas and mercury vapor. Phosphor and protective coatings are disposed on the inner surfaces of the envelope and the cavity. An induction coil of A few turns made from silver coated copper wire is wrapped around the envelope in its axial direction. The inductively-coupled axially uniform plasma is generated inside the envelope. The discharge electric field and current form a closed-loop path inside the envelope along its walls. The introduction of the reentry cavity decreases the lamp wall loading without loosing lamp power efficiency and efficacy. The lamp is operated at frequencies from 50 kHz to 200 MHz and RF power from 5 W to 2000 W without the use of ferrite inside of the reentry cavity.

Electrodeless fluorescent lamp with low wall loading

An electrodeless fluorescent lamp comprises a closed-loop (&ldquo;tokamak&rdquo;) 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.

High light output electrodeless fluorescent closed-loop lamp

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 ( ) filled with rare gas and metal vapor, reentrant glass cavity ( ), an induction coil ( ) made from Litz wire, a ferrite assembly comprising a ferrite core ( ) and MnZn ferrite disk ( ), a cooling structure comprising a metal (or ceramic) tube ( ) positioned inside the ferrite core ( ) and a metal (or ceramic) unit ( ) that transmits the heat from the cavity and ferrite assembly to the Edison socket ( ), a thermal shield ( ), and a driver and matching network located inside the lamp base ( ). A protective coating ( ) and phosphor coating ( ) are coated on the inner surface of the envelope ( ) and reentrant cavity ( ). The reflective coating ( ) made from alumina is coated on the inner surface of the cavity ( ) and on the outer surface of the envelope bottom ( ). The mercury pressure is controlled in the envelope by the temperature of the amalgam ( ) positioned in the tubulation ( ) or by the temperature of pure mercury located in the cold spot.

High frequency electrodeless compact fluorescent lamp

Electrodeless discharge lamp

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.

High frequency ferrite-free electrodeless flourescent lamp with axially uniform plasma

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.

Ferrite-free electrodeless fluorescent lamp

An electrodeless inductively-coupled fluorescent lamp which operates at radio frequencies and contains an induction coil (,) which is inserted in a reentrant cavity (,) of the envelope (,) and is spread along the length of the reentrant cavity (,). The coil (,) is disposed within a cylinder (,) 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 (,) and the cavity (,) and therefore improves lamp maintenance and increases lamp life.

Electrodeless fluorescent lamp with spread induction coil

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. The power efficiency of the lamp operated at frequencies 200-300 KHz and its efficacy are the same as those in electrodeless RF lamps operated at frequencies of 2.65 MHz and at 13.56 MHz.

High-frequency electrodeless fluorescent lamp

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.

Electrodeless fluorescent lamp with cold spot control

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. This results in the mutual 'cancellation' of capacitive RF electric fields induced by both windings in the plasma and in a sheath formed between the plasma and the cavity walls. The reduction of the electric field in turn results in the lowering of a direct current voltage across the sheath thereby lowering the energy of ions which are accelerated in this sheath coating. The lowering of ion energy reduces the damage caused by ions and leads to improved maintenance and a longer life lamp.

Electrodeless fluorescent lamp with bifilar coil and faraday shield

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. The RF coil voltage needed for the ignition of the capacitive discharge in the expansion area (23) is substantially lower than that needed for the ignition of the capacitive discharge in the area (14) along the inner cavity walls (4) to decrease the lamp starting voltage. In one of the embodiments of the present invention the expansion is conically shaped and in another it is cylindrically shaped and is used to generate the inductive plasma to increase the light generation in the top part of the bulb (28) and improve light output through the bulb top surface (27).

Growing community of inventors

Needham, MA, United States of America

Oleg A Popov