In an example embodiment, an electrodeless plasma lamp is provided which comprises a lamp body comprising a dielectric material having a relative permittivity greater than 2, and a bulb adjacent to the lamp body, the bulb containing a fill that forms a plasma when RF power is coupled to the fill from the lamp body. An RF feed is coupled to the lamp body and a radio frequency (RF) power source for coupling power into the lamp body through the RF feed is provided. A shortest distance between an end of the bulb and a point on the RF feed traverses at least one electrically conductive material of the lamp body.

Plasma lamp with conductive material positioned relative to rf feed

An oscillator includes an amplifier having an input and an output, a feedback network connected between the input of the amplifier and the output of the amplifier, the feedback network being configured to provide suitable positive feedback from the output of the amplifier to the input of the amplifier to initiate and sustain an oscillating condition, and a tuning circuit connected to the input of the amplifier, wherein the tuning circuit is continuously variable and consists of solid state electrical components with no mechanically adjustable devices including a pair of diodes connected to each other at their respective cathodes with a control voltage connected at the junction of the diodes. Another oscillator includes an amplifier having an input and an output, a feedback network connected between the input of the amplifier and the output of the amplifier, the feedback network being configured to provide suitable positive feedback from the output of the amplifier to the input of the amplifier to initiate and sustain an oscillating condition, and transmission lines connected to the input of the amplifier with an input pad and a perpendicular transmission line extending from the input pad and forming a leg of a resonant “T”, and wherein the feedback network is coupled to the leg of the resonant “T”.

High frequency inductive lamp and power oscillator

A plasma lamp for an electrodeless plasma lamp having a dielectric waveguide body and a bulb positioned, at least in part, in the waveguide body and having at least one end protruding from the waveguide body. A probe is used to couple power into the waveguide body. The power resonates in the waveguide body and ignites a plasma in the bulb. By having one or both ends of the bulb extend beyond the surface of the waveguide body, the ends of the bulb are exposed to reduced electric field intensity, resulting in longer bulb lifetime due to reduced plasma impingement on the interior surfaces of the bulb.

Plasma lamp and methods using a waveguide body and protruding bulb

The electrodeless low-pressure discharge lamp has a lamp vessel (1) with a protuberance (2), in which an electrical coil (4) is situated around a soft magnetic body (3). A heat-resistant envelope (5) separates the coil (4) from the body (3).

Electrodeless low-pressure discharge lamp

A plasma lamp with a positive-loop feedback topology, having a resonating waveguide body and at least one amplifier critically coupled to the body which is stable under all operating conditions both before a plasma is formed and after the plasma reaches steady state. An iterative method for configuring the lamp circuit includes determining the load trajectory of each amplifier under all operating conditions, and overlaying it on a polar-plot showing regions of stability, conditional stability, and instability. If the load trajectory passes through an unstable region, circuit alterations are made to avoid that region.

Plasma lamp with stable feedback amplification and method therefor

An electrodeless lamp apparatus includes an electrodeless, light-transmitting, envelope for housing a rare-earth compound fill, and a termination fixture, electrodelessly coupled to the envelope, adapted to create an electrical condition for exciting the fill. The fill can include mercury and a noble gas, such as argon. The rare-earth compound is preferably a rare-earth halide, such as dysprosium iodide and holmium iodide. The fill can include a halide of mercury, such as HgBr2. One example of a fill is Hg/DyI3 /HoI3 /CsI/HgBr2 /Ar. A second example of a fill is Hg/NdI3 /DyI3 /CsI/Ar. A third example of a fill is Hg/Pr/DyI3 /HgI2 /CsI/HgBr2 /Ar. A fourth example of a fill is Hg/Yb/CsCl/HgCl2 /Ar.

Electrodeless light source having rare earth molecular continua

A light source includes a source of high frequency power, an electrodelsss lamp and a termination fixture for coupling power to the lamp, the fixture having an outer conductor and an inner conductor whose length is adjustable for providing dynamic matching of the impedance of the lamp during the operating mode to the output impedance of the source. Variations in the power level from the source, such as is desirable in providing lamp brightness selectivity, vary both the real and imaginary components of the lamp impedance, and corresponding adjustments of the inner conductor length provide a tuning technique to compensate for these variations.

Adjustable length center conductor for termination fixtures for electrodeless lamps

An electrodeless lamp is positioned at the end of an inner and outer conductor forming a termination fixture, the inner conductor being shaped such that the arc within the lamp during excitation is isolated from the wall of the lamp envelope. The inner conductor may be formed as a hollow helical element thereby providing both an axial and azimuthal electric field component. Alternatively, the inner conductor may be cup-shaped which has a shielding effect to control the electric field strength at the end of the conductor. The helical or cup element and other features of the inner conductor provide both arc shaping and impedance matching between the complex impedance of the lamp during operation and the output impedance of a high frequency power source which is coupled to the termination fixture.

Electrodeless light source having improved arc shaping capability

A starting assist control circuit for an electrodeless light source in which a UV source for assisting in starting an electrodeless lamp is coupled in series with the dc supply for a microwave power source for the lamp so that a reduced dc voltage is supplied to the microwave power source at lamp starting. At staring, a capacitive impedance element is coupled across the inner and outer conductors of the fixture to provide an additional starting assist by creating a condition of resonance in the fixture. A heat responsive bimetallic switch element associated with both the capacitor and the UV source automatically shorts out the UV source and decouples the capacitor after the lamp has started thereby permitting full dc power to the microwave power source during the operating condition of the lamp.

Automatic starting system for solid state powered electrodeless lamps

A starting assist control circuit for an electrodeless light source in which a UV source for assisting in starting an electrodeless lamp is coupled in series with the DC supply for a microwave power source for the lamp so that a reduced DC voltage is supplied to the microwave power source at lamp starting. An electronic circuit is provided which continuously decreases the DC current through the UV source and increases the DC voltage for the microwave power source in relation to the amount of light generated by the electrodeless lamp. More specifically, the emitter and collector of a transistor are coupled across the UV source to provide a shunt path and the potential of the base of the transistor is controlled by a photosensitive resistor which senses the amount of light from the lamp. As the lamp generates increased light, the transistor becomes more conductive, thereby continuously decreasing current to the UV source and increasing voltage to the microwave power source.

William H. McNeill

Papers

Electrodeless light source having rare earth molecular continua

Adjustable length center conductor for termination fixtures for electrodeless lamps

Electrodeless light source having improved arc shaping capability

Automatic starting system for solid state powered electrodeless lamps

Continuous automatic starting assist uv circuit for microwave powered electrodeless lamps