摘要:
Electrodeless arc tubes for high pressure sodium discharge lamps comprise a substantially tubular, translucent body formed from a material comprising sintered polycrystalline alumina. The body has an inside diameter and an outside diameter and a given length. A fill comprising sodium and xenon are loaded within the body. At least one end-seal is provided for the body, the end-seal comprising a first alumina disc sealed within the inside diameter by compression, the first disc being spaced inwardly from an end of the body and having a substantially centrally located aperture therein. A second alumina disc seals the aperture, the second disc being bonded to the first disc and to the inner wall of the body by a sealing frit.
摘要:
A ceramic discharge vessel is provided wherein the vessel comprises a hollow body for enclosing a discharge and the hollow body is made of a polycrystalline dysprosium oxide containing a luminescent dopant that emits one or more visible light wavelengths when stimulated by radiation generated by the discharge. Preferably, the polycrystalline dysprosium oxide has been doped with one or more of europium, cerium, or terbium in an amount from about 0.1 to about 10 percent by weight on an oxide basis.
摘要:
An arc tube for an electrodeless metal halide discharge lamp has an arc chamber fabricated from a material selected from the group consisting of magnesia-doped polycrystalline alumina, silicon dioxide doped polycrystalline alumina and monocrystalline alumina. The arc chamber is tubular and has at least one end and has a given outside diameter. At least one end cap closes the at least one end of the arc chamber, the end cap being formed from magnesia-doped polycrystalline alumina and comprising a substantially cup-shaped member having an inside diameter which is sealed to the outside diameter of the arc chamber by a shrink-fit.
摘要:
An arc tube for an electrodeless metal halide discharge lamp has an arc chamber fabricated from a material selected from the group consisting of magnesia-doped polycrystalline alumina, silicon dioxide doped polycrystalline alumina and mono-crystalline alumina. The arc chamber is tubular and has at least one end and has a given outside diameter. At least one end cap closes the at least one end of the arc chamber, the end cap being formed from magnesia-doped polycrystalline alumina and comprising a substantially cup-shaped member having an inside diameter which is sealed to the outside diameter of the arc chamber by a shrink-fit.
摘要:
A high intensity discharge lamp includes a ceramic envelope that defines an enclosed volume that is filled with a pressurized gas, the envelope having an exterior with axial poles and an equator and, when viewed in longitudinal cross section, plural exterior steps extending in series from the respective axial pole to the equator, each of the steps having a flat surface that is angled to refract light from inside the envelope toward a plane of the equator. The flat surfaces may be planar (plural facets in concentric tiers) or annular and the envelope may have a spherical interior surface. The lamp may have a reflector with an aperture that is aligned with the respective axial pole.
摘要:
There is described a sealing composition for sealing aluminum nitride and aluminum oxynitride ceramics comprising: a mixture of SiO2, at least one other metal oxide, and a silicon additive comprising at least one of silicon metal or a silicide. The silicon additive acts to suppress the formation of nitrogen bubbles during the sealing of articles comprised of aluminum nitride or aluminum oxynitride ceramics, e.g., as in the case of a ceramic discharge vessel for a high intensity discharge lamp.
摘要:
The present invention is a ceramic discharge vessel for use in high-intensity-discharge (HID) lamps. The discharge vessel has a ceramic body and at least one seal region comprised of an aluminum oxynitride material. The seal region further has a surface layer for contacting a frit material wherein the surface layer is less reactive than the aluminum oxynitride material with respect to the molten frit during sealing. Preferably, the surface layer has a lower nitrogen content than the aluminum oxynitride material. The less reactive surface acts to minimize the formation of bubbles in the sealing frit during the sealing operation.
摘要:
A method of producing a ceramic metal halide discharge lamp having a monolithic seal between a sapphire (single crystal alumina) arc tube and a polycrystalline alumina (PCA) end cap. The method includes the steps of providing an arc tube of fully dense sapphire and providing an end cap made of unsintered compressed polycrystalline alumina powder doped with magnesium oxide and yttrium oxide. The end cap is heated until it is presintered to remove organic binder material at a low temperature relative to the sintering temperature. The presintered end cap is placed on an end portion of the arc tube to form a close interface between the two. The presintered end cap and adjacent arc tube are then heated to until the end cap is fully sintered onto the arc tube and the sapphire tube grows into the end cap. A monolithic seal is formed along the interface between the end cap and the arc tube as the sapphire tube grows into the polycrystalline alumina end cap. The yttrium oxide promotes increased growth between sapphire tube and the PCA end cap and is not detrimental to the metal halide chemistry, nor subject to erosion by the metal halide chemistry.
摘要:
A new and improved bonded ceramic-metal article and the method of making the article is described. The ceramic-metal article comprises a ceramic article, such as a lanthana-strengthened yttria article, bonded to a metal article, such as niobium, by a layer of a brazing material to form a bonded ceramic-metal article. The method of bonding the ceramic article to the metal article comprises placing the brazing alloy, such as a brazing alloy consisting essentially of 63% by weight silver, 35.25% by weight copper, and 1.75% by weight titanium, between the lanthana-strengthened yttria article and the niobium article and heating the layered structure in vacuum at about 50 degrees centigrade above the liquidus temperature of the brazing alloy for a period of about 5 minutes. Another method of bonding the ceramic article comprises coating a surface of the lanthana-strengthened yttria article with a group IVB metal, such as titanium, hafnium, and zirconium then placing a different brazing alloy, such as a brazing alloy consisting essentially of 72% by weight silver and 28% by weight copper or a brazing alloy consisting essentially of 82% by weight gold and 18% by weight nickel, between the coated lanthana-strengthened yttria article and the niobium article and heating the layered structure in vacuum at about 50 degrees centigrade above the liquidus temperature of the brazing alloy for a period of about 5 minutes.
摘要:
A thermal shock apparatus comprises a hot gas stream impinging means, a hot gas stream impinging control means, a positioning means for the hot gas stream impinging means, and a sample holding means. A sample is subjected to an essentially instantaneous impingement of a hot gas stream upon a predetermined area of the sample when a heat gun is moved past heat deflection foils and positioned above the sample causing a thermal shock within the sample.