摘要:
A method for applying a protective coating to the inner surface of the arc tube of a high-intensity metal halide discharge lamp involves dosing the arc tube with an inert gas that is doped with a metal hydride gas. Preferably, the metal hydride gas comprises silane. The arc tube is heated to a sufficiently high temperature to decompose the silane gas. As a result, silicon is deposited as a protective coating on the inner surface of the arc tube wall. The hydrogen gas that is generated by the silane decomposition is removed from the system either by pumping it out before dosing the arc tube with the final arc tube fill, or by diffusion through the arc tube wall during operation of the lamp.
摘要:
A pair of starting electrodes are provided for an electrodeless high-intensity-discharge lamp arc of the type having an envelope situated within the bore of an excitation coil and in the interior of which envelope is to be provided a plasma arc discharge driven by the excitation coil. Each of the starting electrodes is a conductive ring disposed adjacent to an associated one of an opposed pair of envelope surfaces, and connected to an opposite end of the excitation coil. A high-voltage signal coupled between the starting electrodes causes an electric field to be produced sufficient to create a glow discharge in the arc tube, and cause an almost instantaneous transition to a high-current solenoidal discharge to form the discharge plasma responsive to the normal field provided by the excitation coil.
摘要:
A compact fluorescent lamp comprises a substantially cylindrical, tapered envelope with a correspondingly tapered partition disposed within the envelope so as to define a folded discharge path having a length approximately twice the length of the envelope. The taper of the partition and envelope permit easy assembly of the lamp with minimal disturbance of a prior applied phosphor coating. In accordance with one embodiment of the present invention, the partition is formed using shaping wedges applied to a partially molten glass bulb so as to produce a seamed partition extending almost to the closed end of the bulb. The partition in the lamps of the present invention sealably separate one discharge path portion from another.
摘要:
An electrodeless high intensity discharge lamp having an excitation coil disposed about an arc tube includes thermal apparatus for ensuring that a metal halide condensate forms a protective film on the portion of the arc tube which is nearest the plasma arc discharge during lamp operation. For a short, cylindrical arc tube, the thermal apparatus comprises a heat shield situated on the top and/or bottom thereof. In one embodiment, the bottom of the arc tube is concave to ensure that the condensate does not collect on the bottom of the arc tube. The excitation coil may be situated sufficiently close to the arc tube to ensure that enough heat is removed from the side wall of the arc tube to a heat sink so that the protective metal halide film forms on the inner surface of the arc tube wall. An outer glass envelope is preferably situated between the arc tube and the excitation coil, which envelope also functions to remove heat from the arc tube side wall.
摘要:
Jet engine fuel igniters are excited with a current waveform which maintains an intermediate current value until a discharge has separated from the igniter surface. The current then rises to a higher level to provide sufficient energy for ignition of an air-fuel mixture. Ignition reliability is thus increased and the effects of erosion on the igniter surface are decreased.
摘要:
A single starting electrode is provided for an electrodeless high-intensity-discharge lamp arc of the type having an arc tube situated within the bore of an excitation coil and in the interior of which arc tube is to be provided a plasma arc discharge driven by the excitation coil. The starting electrode is a conductive conical spiral having a narrower end disposed adjacent to one of the arc tube surfaces. A high voltage is formed by induction, as the spiral electrode receives an RF magnetic flux, to cause an electric field to be produced sufficient to create a glow discharge in the arc tube, and cause a rapid transition to a high-current solenoidal discharge to form the discharge plasma responsive to the normal field provided by the excitation coil.
摘要:
An electrostatic shield is provided between the induction coil and the arc tube of an electrodeless HID lamp. In one embodiment, the shield is a transparent glass cylinder coated with a thin, transparent, conductive layer of tin oxide. In another embodiment, the electrostatic shield is a conductive, transparent tin oxide coating applied to either the inner or outer surface of an outer light-transmissive jacket surrounding the arc tube. The tin oxide layer is discontinuous so as to minimize currents induced in the conductive tin oxide layer by the induction coil. The thickness of the tin oxide layer is sufficient to make it conductive and form an approximately equipotential surface, thereby shielding the arc tube and plasma discharge from intense electric fields, reducing arc tube wall damage and increasing lamp life. In addition, tin oxide functions as an infrared reflector which returns infrared radiation to the arc tube, resulting in higher efficacy. Other advantages of the electrostatic shield include: a lower color temperature, further improving efficacy; and a lower rate of free iodine formation in lamps employing metal iodide fills, further reducing wall damage.
摘要:
An electrodeless high intensity discharge (HID) lamp having an arc tube, a starting aid, and an outer jacket all integrally formed of fused quartz, includes an excitation circuit for providing RF energy effective for initiating and maintaining a gas discharge within the arc tube. The arc tube is positioned within the outer jacket such that a minimum space exists between the outer jacket and the arc tube thereby allowing the efficient coupling of such RF energy to the arc tube by means of an excitation coil wound in close proximate location to the arc tube. The starting aid is of a substantially smaller dimension than the arc tube thereby allowing for a second spacing to occur above the arc tube. This second spacing is effective for optimum thermal management of heat generated within the outer jacket. The upper end of the outer jacket has an integrally formed annular groove for receiving an annular support member effective for securing the HID lamp to a lighting fixture.
摘要:
A metal vapor discharge lamp includes a cathode comprising a reservoir of liquid cesium. Metallic cesium which is eroded from the cathode surface by the action of the discharge is returned to the reservoir by the combined effects of gravity, evaporation, condensation, and diffusion to provide a highly stable, long-lived lamp.The intense infrared pulse output of cesium vapor discharge lamps of the present invention is well suited for triggering light-activated semiconductor switches through dielectric pipe networks and for pumping neodymium glass or neodymium-YAG lasers.
摘要:
A metal vapor discharge lamp includes a cathode comprising a reservoir of liquid cesium. Metallic cesium which is eroded from the cathode surface by the action of the discharge is returned to the reservoir by the combined effects of gravity, evaporation, condensation, and diffusion to provide a highly stable, long-lived lamp.The intense infrared pulse output of cesium vapor discharge lamps of the present invention is well suited for triggering light-activated semiconductor switches through dielectric pipe networks and for pumping neodymium glass or neodymium-YAG lasers.