Abstract:
Spurious electromagnetic radiation from an electrodeless fluorescent lamp having a phosphor-coated, globular glass envelope containing an ionizable gas surrounding at least a portion of a toroidal magnetic core is reduced by situating a conductive loop about the envelope such that the loop and core planes are normal to each other. The loop also acts as the harp for a lampshade. Radio frequency energy, coupled into the gas from the core to ionize and excite the gas to emit ultraviolet radiation and thus stimulate visible radiation from the phosphor, also radiates from the lamp. The loop, driven by the radiated radio frequency energy, creates an opposing electromagnetic field. Cancellation of the radiated radio frequency energy thus tends to occur at a distance from the lamp, sharply reducing electromagnetic interference from the lamp.
Abstract:
An electrodeless light source having a termination fixture adapted for connection to a high frequency power source has an electrodeless lamp with a self-contained ultraviolet excitation source and a means for coupling power to the electrodeless lamp. The electrodeless lamp includes a main lamp cavity and an exciter lamp cavity within a single envelope. When power is applied to the fixture, the exciter lamp cavity emits ultraviolet radiation which assists starting of the arc discharge in the main lamp cavity.
Abstract:
In an electrodeless fluorescent lamp of the type including a sealed, light transmissive, envelope including an elongate inner wall defining an open-ended cavity and an outer wall surrounding the inner wall to form a generally annular, hollow cavity therebetween, the annular cavity being charged with an ionizable gaseous medium, an induction coil positioned within the open-ended cavity, and a radio frequency oscillator connected to the coil, the coil and the oscillator initiating and maintaining ionization of the medium to form an ultraviolet light emitting discharge, the inner surface of the outer wall of the envelope being coated with a phosphor which emits visible light when excited by ultraviolet light, the improvement wherein the outer surface of the inner wall is coated with a layer of an electrically insulative ultraviolet light reflective material which is overcoated with a phosphor layer. Such improvement yields an increase in visible light production of the order of 50% to 100%.
Abstract:
A resonance lamp having a controllable chemical decomposition source of a parent species and a chemical getter sink in a sealed RF excited discharge. The discharge occurs in a second, extremely pure gas which is present in great excess over the gas produced by chemical decomposition. Excitation of species whose emission is desired occurs by electron impact or energy transfer from the major species which are, in turn, excited by the electron impact.
Abstract:
A microwave-excited light emitting device is provided comprising an electrodeless evacuated discharge lamp containing ionizable elements and mounted in the frequency determining resonator of a microwave oscillator. The oscillator resonator is tuned to provide a microwave frequency of sufficiently high frequency to provide ionization and excitation of the elements within the electrodeless discharge lamp while mitigating deterious ion bombardment of the walls of the electrodeless discharge lamp. By placing the lamp in the oscillator resonator any changes in the electrical characteristics of the lamp after firing will cause a frequency change in the oscillator allowing the lamp and the oscillator to remain in tuned relationship. However, the oscillator is further provided with thermal isolation means to isolate the lamp from the active device within the oscillator such as a vacuum tube or a solid state device. The light-emitting device is further provided with heating means to conduct externally generated heat to the lamp thermally independently of the active device. In this manner the lamp may be operated at a steady, and preferably elevated, temperature without exposing the active device to excessive heat which would have a deleterious effect on the life of the active device.
Abstract:
An electrodeless, halogen gas microwave-induced discharge device, particularly adapted for use as a power limiter stage, which has no wires connected to it. Incorporated into the discharge device is a free electron emitter comprising tritium adsorbed into a layer of material such as titanium or yttrium. The tritium yields sufficient initiatory electrons to prime the microwave gap so as to yield a short interval for radio-frequency breakdown of the gas, and to yield repeatable discharge characteristics with each incident radio-frequency pulse.