摘要:
An electric gas ignitor is disclosed having a gas igniting fiber comprising a core of conductive refractory material and an outer, high strength, oxidation resistant coating. One aspect of the invention concerns a primary current path defined by at least a portion of the fiber core and comprising a material having a highly uniform resistance per unit length. A substantially uniform temperature distribution is thereby promoted on the fiber surface and the formation of localized "hot spots" is inhibited. The primary current path is preferably an anisotropic material having a preferred crystal orientation which uniformly conducts electricity along the fiber length.A second aspect of the invention is directed to the inclusion of a diffusion-barrier material between the fiber core and the oxidation-resistant coating to prevent diffusion of the core and coating, which changes the fiber operating temperature and decreases its operating life. The diffusion-barrier material is preferably refractory, closely packed, dense and, more perferably, is an anisotropic material having its preferred crystal orientation in a direction which inhibits the diffusion while forming the primary current path of the fiber.
摘要:
Radioactive materials are used to assist in starting a discharge in an electrodeless light source. The radioactive emissions predispose on the inner surface of the lamp envelope loosely bound charges which thereafter assist in initiating discharge. The radioactive material can be enclosed within the lamp envelope in gaseous or non-gaseous form. Preferred materials are krypton 85 and americium 241. In addition, the radioactive material can be dispersed in the lamp envelope material or can be a pellet imbedded in the envelope material. Finally, the radioactive material can be located in the termination fixture. Sources of alpha particles, beta particles, or gamma rays are suitable. Because charges accumulate with time on the inner surface of the lamp envelope, activity levels as low as 10.sup.-8 curie are effective as starting aids.
摘要:
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 HgBr.sub.2.One example of a fill is Hg/DyI.sub.3 /HoI.sub.3 /CsI/HgBr.sub.2 /Ar.A second example of a fill is Hg/NdI.sub.3 /DyI.sub.3 /CsI/Ar.A third example of a fill is Hg/Pr/DyI.sub.3 /HgI.sub.2 /CsI/HgBr.sub.2 /Ar.A fourth example of a fill is Hg/Yb/CsCl/HgCl.sub.2 /Ar.
摘要:
A solid state microwave power source for providing microwave power to excite an electrodeless lamp is designed so as to provide an acceptable impedance matching characteristic during lamp warm-up when the lamp impedance is high and changing with temperature to provide sufficient power to the lamp during the running state when the lamp impedance is matched to the source. The microwave power source includes a dc power source providing power at variable levels, a microwave oscillator receiving the dc power to produce a microwave signal, and a microwave power amplifier. The oscillator has a transistor in a common base configuration, a microstrip capacitive feedback element to sustain oscillations, and an output impedance matching arrangement formed from microstrip. The microwave signal is amplified in the solid state power amplifier having a power transistor in a common base configuration. An impedance matching section between the amplifier and the input of a termination fixture for the lamp includes a length of transmission line which transforms the input impedance of the fixture to a level at the collector of the power transistor in the amplifier so as to maximize the power delivered to the lamp at reduced power levels while maintaining the collector voltage within a safe limit.
摘要:
The present invention involves a combination of active and passive optical or opto-electronic device alignment techniques. Passive alignment is used for two axial lateral directions and all three axial rotational directions (yaw, pitch and roll). In such passive alignment, only the substrate is micromachined with passive alignment structures. One-dimensional active alignment is then used for the remaining axial lateral direction.
摘要:
A method of passively aligning optical receiving elements such as fibers to the active elements of a light generating chip includes the steps of forming two front and one side pedestal structures on the surface of a substrate body, defining a vertical sidewall of the chip to form a mating channel having an edge at a predetermined distance from the first active element, mounting the chip epi-side down on the substrate surface, and positioned the fibers in fiber-receiving channels so that a center line of each fiber is aligned to a center line of a respective active element. When mounted, the front face of the chip is abutting the contact surfaces of the two front pedestals, and the defined sidewall of the mating channel is abutting the contact surface of the side pedestal. The passive alignment procedure is also effective in aligning a single fiber to a single active element.
摘要:
A method of passively aligning optical receiving elements such as fibers to the active elements of a light generating chip includes the steps of forming two front and one side pedestal structures on the surface of a substrate body, defining a vertical sidewall of the chip to form a mating channel having an edge at a predetermined distance from the first active element, mounting the chip epi-side down on the substrate surface, and positioning the fibers in fiber-receiving channels to that a center line of each fiber is aligned to a center line of a respective active element. When mounted, the front face of the chip is abutting the contact surfaces of the two front pedestals, and the defined sidewall of the mating channel is abutting the contact surface of the side pedestal. The passive alignment procedure is also effective in aligning a single fiber to a single active element.
摘要:
Apparatus for repeatedly generating a staircase ramp voltage pulse on a bus connected to a capacitive load employing a set of DC voltage sources, each producing a voltage of a step in the staircase ramp voltage. A storage capacitor is connected between the output terminal of each voltage source and ground. An FET switch is connected between each of the output terminals and the bus and between ground and the bus. A timing circuit closes each of the FET switches in order to produce a staircase ramp voltage on the bus charging the capacitive load. When it is desired to discharge the capacitive load, the timing circuit then closes the switches in reverse order. Each storage capacitor is charged by the discharging capacitive load to a voltage above the voltage of its associated voltage source. The energy thus stored is used during the next cycle to contribute to the energy required to charge the capacitive load on the bus.
摘要:
In a light source in which an electrodeless lamp is excited by high frequency power coupled into a lamp termination fixture having an inner and outer conductor, the fixture has a dynamically variable characteristic impedance, thereby facilitating dynamic matching of the variable impedance of the lamp during the lamp-off to lamp-run conditions to the output impedance of the power source. This feature is possible because the position of the inner conductor with respect to the outer conductor is controlled as a function of the heat generated within the fixture. The inner conductor is made of a conductive material having a non-uniform coefficient of thermal expansion. When the fixture is cold, the lamp and the lamp-coupled end of the inner conductor are substantially concentric to the outer conductor thereby creating a high characteristic impedance to match the high starting lamp impedance to the source impedance. When the lamp is running, the inner conductor and lamp become eccentric to the outer conductor due to the heat generated in the fixture, thereby reducing the fixture characteristic impedance to match the lower lamp impedance to the output impedance of the source.
摘要:
The present invention involves a combination of active and passive optical or opto-electronic device alignment techniques. Passive alignment is used for two axial lateral directions and all three axial rotational directions (yaw, pitch and roll). In such passive alignment, only the substrate is micromachined with passive alignment structures. One-dimensional active alignment is then used for the remaining axial lateral direction.