Abstract:
An RF powered electrodeless lamp (9) utilizing an inductive tuner (14) in the waveguide (6) which couples the RF power (2) to the lamp cavity (10, 12), for reducing reflected RF power and causing the lamp (9) to operate efficiently.
Abstract:
An electrodeless lamp bulb (12) is rotated at sufficient rate to obviate isolated discharges. A coaxially excited electrodeless lamp bulb (12) is rotated in such manner that different regions of the bulb are near the high field region caused by the inner coaxial conductor, thus preventing arc attachment from occurring. An electrodeless lamp bulb (12) is rotated at a high speed sufficient to improve lamp efficiency and reduce cooling requirement. An electrodeless lamp bulb (12) is provided with wall of reduced thickness at the area of the bulb (12) where it is desired to condense the fill upon turning off the power, thus providing for quicker starting.
Abstract:
An electrodeless lamp includes a stationary bulb (10) containing a fill for producing a discharge, the fill has a primary radiating material which ordinarily produces an unstable discharge in the absence of bulb rotation. The fill further includes an alkali metal in an amount sufficient to stabilize the discharge without bulb rotation. The alkali metal may be, for example, cesium bromide. Preferably, the fill is excited by a non-stationary electric field (E, E1) such as, for example, a circular polarized electric field.
Abstract:
An ultra bright, low wattage inductively coupled electrodeless aperture lamp is powered by a solid state RF source in the range of several tens to several hundreds of watts at various frequencies in the range of 400 to 900 MHz. Numerous novel lamp circuits and components are disclosed including a wedding ring shaped coil having one axial and one radial lead, a high accuracy capacitor stack, a high thermal conductivity aperture cup and various other aperture bulb configurations, a coaxial capacitor arrangement, and an integrated coil and capacitor assembly. Numerous novel RF circuits are also disclosed including a high power oscillator circuit with reduced complexity resonant pole configuration, parallel RF power FET transistors with soft gate switching, a continuously variable frequency tuning circuit, a six port directional coupler, an impedance switching RF source, and an RF source with controlled frequency-load characteristics. Numerous novel RF control methods are disclosed including controlled adjustment of the operating frequency to find a resonant frequency and reduce reflected RF power, controlled switching of an impedance switched lamp system, active power control and active gate bias control.
Abstract:
A microwave electrodeless lamp includes an electrodeless bulb (34) enclosing a light generating fill, a mesh screen (32) surrounding the bulb with at least half the bulb volume completely within the mesh; the mesh together with other conductive surface defining a microwave cavity (114), a magnetron (46) for providing microwave energy, and a waveguide (40) for transmitting the microwave energy from the magnetron to the microwave cavity, wherein the minimum distance between the outer bulb surface and the closest portion of the mesh is selected in accordance with the temperature of the bulb during operation and the temperature at which the screen material degrades. Other embodiments and aspects are also disclosed.
Abstract:
A source of microwave energy (11) is connected to a waveguide (14) having a slot (16) along one wall (17) thereof. A nominally cylindrical cavity (18) enclosing an electrodeless lamp (21) is closed at one end and coupled at a second end to the slot (16). The nominally cylindrical cavity (18) has a non-cylindrical surface portion (26) which increases coupling from the slot (16) to a second resonant mode which is orthogonal to a first primary resonant mode, creating a high amplitude standing wave in the region of the electrodeless lamp. Once ignition of the lamp occurs, the impedance of the lamp decreases significantly, and most of the microwave power for sustaining illumination is coupled to the electrodeless lamp in the first resonant mode producing a substantially matched load to the microwave source (11).
Abstract:
A microwave lamp having a compact structure utilizing a coupling slot which is located off center in one direction and a canted bulb stem which is located off center in the opposite direction. A non-conventional waveguide is used which has about the width of a WR-284 waveguide and about the length of a WR-340 waveguide.