Electric lamp or space discharge component or device manufacturi – Process – With assembly or disassembly
Reexamination Certificate
1999-12-10
2001-03-20
Ramsey, Kenneth J. (Department: 2879)
Electric lamp or space discharge component or device manufacturi
Process
With assembly or disassembly
C313S318070, C313S318080
Reexamination Certificate
active
06203392
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a novel base configuration for a single ended quartz lamp and associated ceramic base portion as are used in projection lighting applications. More particularly, this invention relates to such a lamp and base configuration that provides the necessary prefocus characteristics using a reduced number of components as well as having associated therewith, a simpler process of manufacture.
BACKGROUND OF THE INVENTION
Conventional single ended quartz (SEQ) lamps for use in projection applications typically consist of a quartz wire lamp focused and cemented in a ceramic base with two attached base pins leading externally of the lamp envelope for connection to a source of power. The quartz wire lamp includes a filament, foil leads that are disposed within the seal region of the lamp envelope, and external molybdenum leads which are connected to power. The ceramic base includes brass pins with center holes inserted into openings in the ceramic base, and typically staked in place. The electrical connection from a power source to the filament is a four piece system comprising the brass pins, nickel wire leads, molybdenum wire leads, and molybdenum foil leads.
Specifically, one embodiment of an SEQ lamp known in the art and sold by General Electric is shown in
FIGS. 1-3
. This SEQ lamp is a standard quartz wire lamp with a filament housed inside a quartz envelope. The two ends of the filament are welded to wire lamp foil leads. The foil leads are then sealed in one end of the quartz envelope. External molybdenum leads welded to the wire lamp foil leads extend out of the seal.
Specifically, two 0.060″ (1.5 mm) diameter, nickel plated brass pins are inserted and staked into holes in the ceramic base where the holes extend from the inside cavity of the base to the other end of the ceramic base. The nickel plated brass pins are hollow. Further, each pin has a center hole therethrough and out the outer end.
The external molybdenum leads on the wire lamp are then trimmed below the seal with no more remaining length than needed to weld outer extension leads thereon. Nickel outer leads are welded to the exposed portions of the external molybdenum leads. The welded outer extension leads are threaded through the center holes in base pins to the correct light center length (LCL), i.e. the distance from the center of the filament to the bottom of the ceramic base.
The wire lamp and ceramic base are clamped in place and the excess welded outer extension lead wire is trimmed away. The remaining lead wire is welded to the inside of the nickel plated brass pins. Cement is introduced through a center hole in the bottom of the base whereby the inside cavity of the ceramic base around the wire lamp seal is filled with cement. The wire lamp is then adjusted to center the coil over the base in both the up-down (vertical) and the left-right (horizontal) direction. Finally, the lamp assembly is heated to set the cement.
This and other current designs for based SEQ lamps for projection applications include numerous parts that assist in the focusing operation during assembly. The focusing operation adds significant time and labor expense to the manufacture of each SEQ lamp for projection applications. These current designs with large ceramic bases with large aliquots of cement around quartz wire lamp seals retain heat and thus may prohibit cooling needed for prevention of lamp failure from overheated seals.
SUMMARY OF THE INVENTION
The present invention is a single ended, quartz projection lamp including a more advanced quartz wire lamp, a smaller ceramic base, and a cement fill. The quartz wire lamp envelope is hermetically sealed to define an inner chamber housing a filament. The filament has two ends welded to foil leads in the hermetic seal. The ceramic base has an envelope receiving slot therein with a pair of holes extending from the slot through the ceramic base. The pair of leads, electrically connected to the ends of the filament, extend into and through the ceramic base where an exposed portion of each lead is directly connectable to a power source. The cement fill is in the envelope slot below the seated hermetic seal of the envelope for bonding the envelope to the base.
The present invention is further a method of assembling a single ended quartz projection lamp where the correct light center length as defined from the center of the filament of the lamp to the bottom of the base of the lamp is always met by assembly of the lamp without adjustment of the lamp in the base. The method involves inserting the pair of wire lamp leads extending from the wire lamp envelope through a pair of corresponding holes in a slot within a ceramic base such that ends of the leads extend through and out of the ceramic base. The method then includes stopping the insertion of the wire lamp leads into the holes by a raised portion of the envelope seal engaging an outer lip of the slot in the ceramic base. The method finally includes applying cement into the slot below the seal to secure the envelope to the ceramic base.
In addition, the method includes in more detailed embodiments, shaping an exposed portion of the wire lamp leads to form base pin ends connectable to a power source. The method may further include electrically connecting the pair of wire lamp leads to a corresponding pair of filament ends. In more detail, the method includes defining an envelope hermetically sealed to contain a filament with the pair of filament ends connected to leads in the hermetic seal, as well as defining each wire lamp lead as a molybdenum foil welded to an outer molybdenum wire which in turn is welded to an outer nickel wire.
Accordingly, it is an objective of the present invention to improve the design and assembly process for manufacturing two-pin single ended quartz lamps having a prefocused base for projection applications.
One of the advantages of the present invention is a simpler design.
In furtherance of this advantage, the present invention advantageously uses less than the four parts required in the prior art designs from the filament to the power source.
Another advantage of the present invention is the use of fewer parts to obtain a prefocused base on a two pin single ended quartz lamp.
An additional advantage of the present invention is ease and speed of assembly.
An even further advantage of the present invention is the reduced time and labor cost needed for assembly.
Another advantage is the elimination of extra pins that need to be affixed to the leads.
A further additional advantage is a smaller ceramic base.
Another advantage is improved cooling of the lamp.
An additional advantage is prevention of overheating of seals and thus premature lamp failure from overheated seals.
Other advantages include more exposed lamp surface area for better cooling.
Still other advantages and benefits of the invention will become apparent to those skilled in the art upon a reading and understanding of the following detailed description.
REFERENCES:
patent: 3469140 (1969-09-01), Bottone et al.
patent: 4785218 (1988-11-01), Kohl et al.
Hatfield Donald E.
Rachel Bernard W.
Garcia Christine K.
General Electric Company
Hopper Todd Reed
Luo Li-Hua
Ramsey Kenneth J.
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