Electric lamp and discharge devices – With optical device or special ray transmissive envelope – Reflector
Reexamination Certificate
1999-10-26
2001-11-13
Patel, Nimeshkumar D. (Department: 2879)
Electric lamp and discharge devices
With optical device or special ray transmissive envelope
Reflector
C313S623000, C313S634000, C313S110000, C313S570000, C313S573000, C313S574000, C315S246000
Reexamination Certificate
active
06316867
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to arc lamps, and specifically to components and methods used to reduce the cost of manufacturing xenon arc lamps.
2. Description of the Prior Art
Short arc lamps provide intense point sources of light that allow light collection in reflectors for applications in medical endoscopes, instrumentation and video projection. Also, short arc lamps are used in industrial endoscopes, for example in the inspection of jet engine interiors. More recent applications have been in color television receiver projection systems.
A typical short arc lamp comprises an anode and a sharp-tipped cathode positioned along the longitudinal axis of a cylindrical, sealed concave chamber that contains xenon gas pressurized to several atmospheres. U.S. Pat. No. 5,721,465, issued Feb. 24, 1998, to Roy D. Roberts, describes such a typical short-arc lamp. A typical xenon arc lamp, such as the CERMAX marketed by ILC Technology (Sunnyvale, Calif.) has a three-legged strut system that holds the cathode electrode concentric to the lamp's axis and in opposition to the anode.
The manufacture of high power xenon arc lamps involves the use of expensive and exotic materials and sophisticated fabrication, welding, and brazing procedures. Because of the large numbers of xenon arc lamps being produced and marketed, every opportunity to save money on the materials and/or assembly procedures is constantly being sought. Being the low-cost producer in a market always translates into a strategic competitive advantage.
For example, the CERMAX-type arc lamp
100
shown in FIG.
1
and sold in the commercial market can easily require as much as forty-eight percent in material costs and fifty-two percent in labor costs. The total manufacturing cost acts to set the minimum amount that can be charged at retail. The supply-versus-demand rule therefore tends to limit the production volumes that can be sold because of the high price points that must be charged. The lamp
100
is conventional and comprises an optical coating
102
on a sapphire window
104
, a window shell flange
106
, a body sleeve
108
, a pair of flanges
110
and
112
, a three-piece strut assembly
114
, a two percent thoria cathode
116
, an alumina-ceramic elliptical reflector
118
, a metal shell
120
, a copper anode base
122
, a base support ring
124
, a tungsten anode
126
, a gas tubulation
128
, and a charge of xenon gas
130
. All of which are brazed together in a complex assembly process. Fewer parts, less expensive materials, simpler tooling, and fewer assembly steps would all help to reduce the costs of making such CERMAX-type arc lamps.
SUMMARY OF THE PRESENT INVENTION
It is therefore an object of the present invention to provide a xenon ceramic lamp that is less expensive to produce than conventional designs.
It is another object of the present invention to provide a low-cost xenon ceramic lamp that works equally as well as more expensive conventional designs.
Briefly, an arc lamp embodiment of the present invention comprises an optical coating on a sapphire window, a window shell flange, and a body sleeve. A gas-fill tubulation attaches to the side of the body sleeve and permits a charge of xenon gas to be injected during manufacture. This contrasts with the prior art where the xenon gas is introduced through the anode base. A single-piece strut assembly is used that is compatible with mass-production techniques. The single-piece strut assembly supports and suspends a cathode inside an elliptical reflector. An anode flange replaces a more conventional shell, copper anode base, and base support ring. A tungsten anode completes the lamp. All of these parts are brazed together in an assembly process that is far less complex than the prior art.
An advantage of the present invention is that a ceramic arc lamp is provided that is less expensive to manufacture compared to prior art designs and methods.
These and other objects and advantages of the present invention will no doubt become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiments which are illustrated in the drawing figures.
REFERENCES:
patent: 4940922 (1990-07-01), Schuda et al.
patent: 6114807 (2000-09-01), Kavanagh
patent: 6135840 (2000-10-01), Kanzaki
patent: 6181053 (2001-01-01), Roberts
patent: 2000-277054 (2000-10-01), None
Roberts Roy D.
Romero Rodney O.
EG&G ILC Technology, Inc.
Law Offices of Thomas E. Schatzel, A. Prof. Corp.
Patel Nimeshkumar D.
Roy Sikha
Schatzel Thomas E.
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