Patent Application
20150137685
N/A
The present disclosure relates generally to a lamp with a press seal and a fuse, in particular for high current rapid thermal processing (“RTP”) lamps.
The following lamps are known: U.S. Pat. No. 5,345,144 (Mahonski); U.S. Pat. No. 5,205,769 (Mahonski); U.S. Pat. No. 5,264,756 (Westlund, Jr.); U.S. Pat. No. 4,066,926 (Newton); U.S. Pat. No. 3,717,783 (Notelteirs); U.S. Pat. No. 4,570,104 (Janssen); U.S. Pat. No. 6,639,364 (Woods); U.S. Pat. No. 4,922,155 (Morris); U.S. Pat. No. 4,132,922 (Newton); U.S. Pat. No. 3,710,169 9 T'Jampens); U.S. Pat. No. 4,415,836 (De Cuester); U.S. Pat. No. 4,398,124 (Kohl); U.S. Pat. No. 3,796,914 (De Caro); and U.S. published Appin. US 2003/0076026 (Trent).
It is known that a conventional RTP lamp contains a filament inside a capsule with a press seal end, the capsule being held inside a stainless steel sleeve with a fuse external to the press seal region. The fuse and press seal portion of the capsule are encased in a potting compound held within the stainless steel sleeve.
Reference should be made to the following detailed description, read in conjunction with the following figures, wherein like numerals represent like parts:
For a thorough understanding of the present disclosure, reference should be made to the following detailed description, including the appended claims, in connection with the above-described drawings. Although the present disclosure is described in connection with exemplary embodiments, the disclosure is not intended to be limited to the specific forms set forth herein. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient. Also, it should be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
In general, the present disclosure concerns a lamp that is sealed with a press seal and having a fuse. Compact high current rapid thermal processing (“RTP) lamps are desired in the marketplace, and find application for example in semiconductor processing where intense heat is required. A relatively long press seal region is used that accommodates, in addition to the conventional filament leads to the exterior of the lamp, the fuse as well, the fuse being disposed inside an inert-gas filled void which is formed in the press seal, the fuse being thus disposed in an inert environment. The void is defined by a bubble formed in the press seal. Alternatively, the void can be defined by an inside region of a glass capillary tube that jackets the fuse and is squeezed into the press seal. Such a lamp draws high current, at or in excess of 5 amps, and provides satisfactory heat dissipation. The fuse is made of metal with a high melting point, such as molybdenum.
Some advantages of the present embodiment are that the lamp capsule does not need to be enclosed in a stainless steel tube or require potting compound. This embodiment reduces the number of components as well as assembly steps such as locating a metal sleeve, inserting potting compound, fuse insulation, and curing the potting material.
Envelope 12 has an inner surface 14 that defines a first enclosed volume 16. A non-oxidizing atmosphere is produced inside enclosed volume 16. In a known manner an inert gas such as nitrogen is introduced into and held in enclosed volume 16. Filament 18 may be a coiled coil tungsten filament as is known in the art. Envelope 12 is made from a quartz tube. In a process known from the conventional art, nitrogen and argon are used to displace the oxygen (and ambient atmosphere) and thus avoid that components of the electrical mount (filament 18, seal foils 28, electrical conductor supports 24, 26, 29, 32, fuse 40) oxidize in the process of the heating. As is known in the art, the inert gas can be introduced into the quartz tube from which envelope 12 is formed through a tabulation or through an open end of the quartz tube, as convenient.
Envelope 12, in press seal region 30 during manufacture, is heated to a plastic state and pressed to enclose and seal with seal foils 28. Over the length of press seal region 30, the thickness of the press seal can be non-uniform. It has been found advantageous that over the region of seal foils 28, the press seal thickness as shown in
In a working example, fuse 40 is made of molybdenum wire having 0.012″ (inch) diameter, this is a size believed suitable for a 620 Watt/92 Volt capsule. One of ordinary skill in the art appreciates to choose an appropriate wire diameter, considering the transversal area of the fuse, depending on the particular choice of wattage and voltage (or current) of the lamp for its particular application.
As shown in for example
An assembly step for forming bubble 36 will be described. In known press sealing processes, heated glass of the quartz tube is formed by a press tool that has two mating faces referred to as press feet. The typical press feet zone is flat, resulting in a conventional flat or generally planar press seal, as is typical in the press seal for the bulb in the region adjacent seal foils 28 or in the most distal region of press seal 30 adjacent the press seal end where external conductors 29, 32 protrude to the exterior. As one of skill in the art will readily appreciate, a portion of the usually flat region of the press foot is provided with a cavity or indent therein, one cavity or indent on each tool face is preferred, and this reliably forms bubble 36 assisted by the flow of inert gas, such as nitrogen. Inert gas from the oxygen flush of filament 18 enclosed in first volume 16 is then also trapped inside bubble 36 and sealed by the press feet tool forming press seal 30.
While several embodiments of the present disclosure have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the functions and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the present disclosure. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings of the present disclosure is/are used.
Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the disclosure described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the disclosure may be practiced otherwise than as specifically described and claimed. The present disclosure is directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the scope of the present disclosure.
All definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms.
The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, are understood to mean “at least one.”
The phrase “and/or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Other elements may optionally be present other than the elements specifically identified by the “and/or” clause, whether related or unrelated to those elements specifically identified, unless clearly indicated to the contrary.
An abstract is submitted herewith. It is pointed out that this abstract is being provided to comply with the rule requiring an abstract that will allow examiners and other searchers to quickly ascertain the general subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims, as set forth in the rules of the U.S. Patent and Trademark Office.
The following is a non-limiting list of reference numerals used in the specification:
