Electric lamp and discharge devices – With gas or vapor – Having a particular total or partial pressure
Reexamination Certificate
1998-11-16
2001-03-13
Patel, Nimeshkumar D. (Department: 2879)
Electric lamp and discharge devices
With gas or vapor
Having a particular total or partial pressure
C313S574000, C313S025000, C313S631000
Reexamination Certificate
active
06201348
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to starting aids and more particularly to starting aids for high intensity discharge (HID) lamps and, still more particularly, to starting aids incorporated in an aluminosilicate outer jacket.
BACKGROUND OF THE INVENTION
HID lamps require a ballast in the electric circuit with the lamp in order to operate. The ballast supplies the requisite open circuit voltage to start and maintain an arc in the discharge tube as well as limiting the current therethrough. One style of ballast uses a high voltage pulse to initiate breakdown in the arc discharge tube. Arc tube breakdown is the first phase of lamp starting and is, therefore, essential for lamp operation. The typical high voltage pulse for a ballast of this type has an amplitude between 3.0 and 4.0 kilovolts with a width of 1.0 &mgr;s at 2.7 kilovolts. The maximum voltage can be increased; however, such an action requires a more expensive base on the lamp and a more expensive socket in the fixture.
There are two commercial ballast methods of applying the typical voltage to the lamp. The first method applies the pulse voltage to the center contact of the lamp base. The second method divides the pulse between the center contact and the shell of the base. The second method, referred to as the split lead design, has the unusual characteristic of floating the lamp lead wires such that both lamp lead wires carry pulse voltage with respect to ground. When the pulse voltage is applied to the lamp, 1.7 kv is applied to the center contact and an opposite potential of approximately equal magnitude is applied to the shell of the lamp.
With the typical high voltage pulse, the HID lamp requires a starting aid to initiate instantaneous breakdown. There are several known aids to reduce the pulse requirements and to make less expensive systems. One such aid adds radioactive krypton 85 to the argon gas contained in the arc tube. Another method is to lower the arc tube buffer gas pressure. Still another employed technique adds a glow bottle that produces ultraviolet light adjacent the arc tube (see U.S. Pat. No. 4,818,915). Yet another technique adds a bubble containing gas to the arc tube seal. This technique also produces ultraviolet light in the area of the arc tube. (See, U.S. Pat. No. 5,323,091 and Ser. No. 08/372,069).
While each of these techniques is workable, they all have some disadvantages. The use of krypton 85 has the attendant difficulties of handling radioactive materials such as gas reclaiming systems and the cost of state and federal licenses.
The use of glow bottles is not advantageous because the glow bottle would have to be inside the aluminosilicate jacket and there simply is not enough room. Positioning outside of the jacket is not workable since the aluminosilicate jacket does not pass UV radiation.
The bubble-in-the-press approach requires extra molybdenum foils to penetrate the bubble. This is difficult to accomplish in the smaller size arc tubes and adds material cost as well as assembly cost. Further, this technique is not workable with a split lead ballast since the voltage applied to the bubble electrode would only be 1.7 kv with respect to the isolated frame and the bubble gas would not breakdown.
DISCLOSURE OF THE INVENTION
It is, therefore, an object of the invention to obviate the disadvantages of the prior art.
It is another object of the invention to provide an improved arc tube assembly with improved starting.
It is another object of this invention to provide a new arc tube assembly that enhances starting.
It is a further object of this invention to provide a new arc tube assembly that is well suited for a reflector lamp.
These objects are accomplished, in one aspect of the invention, by an arc tube assembly for a high intensity discharge lamp, which assembly comprises an arc tube having an arc chamber, oppositely disposed press seals at the ends of the arc chamber, and an electrode and an electrode lead-in sealed into each of the press seals, the electrodes terminating in the arc chamber and the lead-ins terminating externally of the press seals. An arc generating and sustaining medium is contained in the arc chamber and an hermetically sealed jacket containing a partial pressure of a gas that will support lamp starting surrounds the arc tube. The arc tube lead-ins extend beyond the jacket whereby electrical connections are made thereto. A first electrically conductive member is affixed to one of the lead-ins within the jacket and outside of the arc tube, and a second electrically conductive member is affixed to the other of the lead-ins and extends outside of the jacket. A capacitive coupling thus is formed between the first electrically conductive member and the second electrically conductive member that forms the starting aid.
REFERENCES:
patent: 3828214 (1974-08-01), Keeffe et al.
patent: 3900753 (1975-08-01), Richardson
patent: 4134042 (1979-01-01), van HeemsKerck
patent: 5389856 (1995-02-01), Luijks et al.
patent: 5708328 (1998-01-01), Mathews et al.
patent: 5889360 (1999-03-01), Frey et al.
Brates Nanu
Nortrup Edward H.
Wyner Elliot F.
Guharay Karabi
McNeill William H.
Osram Sylvania Inc.
Patel Nimeshkumar D.
LandOfFree
Capacitive coupling starting aid for metal halide lamp does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Capacitive coupling starting aid for metal halide lamp, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Capacitive coupling starting aid for metal halide lamp will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2533652