Abstract: Ignition of an electrodeless lamp, energized by microwave or radio frequency energy, is achieved by disposing a ferroelectric igniter in the lamp envelope along with the fill material. The igniter responds to switching of its spontaneous ferroelectric polarization by emitting electrons that collide with the atoms of the fill material to discharge further electrons and ultimately provide emission of light. In the preferred embodiment, the microwave or radio frequency energy used to excite the fill material is applied to the ferroelectric igniter to cause switching of its spontaneous ferroelectric polarization. Another preferred feature is the securing of the igniter, in the form of a thin patch or wafer, to the inside surface of the lamp envelope in a generally perpendicular orientation to the electric field in the microwave excitation energy.

Abstract: A microwave powered electrodeless lamp includes an improved screen unit having mesh and solid sections with an internal reflector secured at the juncture of the two sections to reflect light into a light-transmitting chamber defined in the lamp microwave cavity by the reflector and the mesh section. A discharge envelope of a bulb is disposed in the light-transmitting chamber. Light emitted from the envelope is prevented by the reflector from entering the cavity portion bounded by the solid section of the screen. The reflector is mounted in the cavity by tabs formed in the screen unit and bendable into the cavity to define support planes abutting respective surfaces of the reflector. The mesh section and tabs are preferably formed by etching a thin metal sheet.

Abstract: A microwave powered electrodeless lamp includes an improved screen unit having mesh and solid sections with an internal reflector to reflect light into a light-transmitting chamber defined in the lamp microwave cavity by the reflector and the mesh section. A discharge envelope of a bulb is disposed in the light-transmitting chamber. Light emitted from the envelope is prevented by the reflector from entering the cavity portion bounded by the solid section of the screen. Replacing mesh material by solid metal material as part of the screen unit significantly reduces leakage of microwave energy from the lamp. The solid section has multiple compliant fingers defined therein for engaging the periphery of a flange on the waveguide unit so that a hose clamp can easily secure the screen to the assembly. Screen units of this type having different mesh section configurations can be interchanged in the lamp assembly to produce different respective illumination patterns.

Abstract: Apparatus for efficiently exciting an electrodeless lamp to produce visible light. A source of microwave energy is coupled to a cylindrical cavity which encloses an electrodeless lamp. The cylindrical cavity includes a sidewall and end wall which is made from a metallic mesh which passes light produced from the electrodeless lamp. The electric field intensity within the cylindrical cavity is increased in the region above the lamp center. The increased electric field intensity produces a more uniform temperature across the bulb service, increasing the rate of plasma heating of gas molecules in the lamp.