Electric lamp and discharge devices – With optical device or special ray transmissive envelope – Reflector
Reexamination Certificate
1999-03-01
2001-05-22
Patel, Nimeshkumar D. (Department: 2879)
Electric lamp and discharge devices
With optical device or special ray transmissive envelope
Reflector
C313S573000, C313S039000, C313S110000
Reexamination Certificate
active
06236147
ABSTRACT:
FIELD OF INVENTION
This invention relates to an arc lamp, and more particularly to such an arc lamp pulsed or continuous having an absorbing medium and/or a backscatter deflector.
BACKGROUND OF INVENTION
Conventional arc lamps, pulsed or continuous, provide a high energy density, high intensity, sharply defined source which is desirable in a number of applications. The high energy density and high intensity make arc lamp sources desirable in spectroscopy where the chemical sensitivity is a direct function of the energy density at the target sample. The high energy density and high intensity are also useful in miniaturization applications such as in fiber optic light transmission for endoscopic uses and generally in photographic illumination applications where a high intensity minute controlled source of illumination is essential. One shortcoming of such lamps is that more than half of the radiation generated is lost because of backscattering of the rearward directed radiation within the arc lamp. Worse still, that lost, backscattered rearward radiation increases the heating of the lamp and contributes to optical noise that interferes with the output beam. In some designs paraboloidal and ellipsoidal internal reflectors have been used to collect and control more of the available arc radiation but because of electrode orientation can cause a void or black hole in the direct radiation, and each of them inadvertently increases magnification at the target which in most applications is undesirable.
SUMMARY OF INVENTION
It is therefore an object of this invention to provide an improved arc lamp of the continuous or pulsed type.
It is a further object of this invention to provide such an improved arc lamp which can substantially increase radiation output without increase in power input.
It is a further object of this invention to provide such an improved arc lamp which can substantially reduce power while maintaining radiation output.
It is a further object of this invention to provide such an improved arc lamp which conserves energy.
It is a further object of this invention to provide such an improved arc lamp which recaptures radiation emitted rearwardly away from the window and redirects through the window with the forward transmitted radiation.
It is a further object of this invention to provide such an improved arc lamp which dramatically reduces optical noise generated by the backscattered rearward directed radiation.
It is a further object of this invention to provide such an improved arc lamp which substantially reduces the heat loss in the arc lamp.
It is a further object of this invention to provide such an improved arc lamp which generates a high energy density, high intensity radiation beam without voids or holes.
It is a further object of this invention to provide such an improved arc lamp which imposes no unwanted magnification.
This invention results from the realization that the optical noise generated in a conventional arc lamp can be reduced by depositing a convex black absorbing medium on the lamp base and that any backscatter radiation not absorbed by the absorbing medium can be preventing from exiting the lamp by an optical deflector positioned between the base and the electrodes of the lamp.
This invention features an arc lamp comprising a housing including a base, an inert gas in the housing, a pair of spaced electrodes in the housing for establishing an arc in the gas to generate a radiation output, a window area on the housing for transmitting forward radiation generated by the arc, and an absorbing medium on the opposite side of the electrodes from the window for preventing backscatter radiation from the arc from passing through the arc and out of the window.
The absorbing medium is preferably located on the housing base and black in color. The absorbing medium may be convex, concave, or flat in shape. There may also be a deflector between the electrodes and the absorbing medium. The deflector has one or even two rearward deflective surfaces. The absorbing medium typically has a roughened top surface to assist in diffusion. The housing and base can be standard TO-5 components.
The arc lamp of this invention includes a housing with a base, an inert gas in the housing, a pair of spaced electrodes in the housing for establishing an arc in the gap to generate a radiation output, a window area on the housing for transmitting forward radiation generated by the arc, and noise reduction means for preventing backscatter radiation from the arc from passing through the arc and out of the window.
The noise reduction means may include or is an absorbing medium on the housing base. The absorbing medium is preferably black or dark in color, convex or concave, and has a roughened surface.
Alternatively, the noise reduction means includes or is a deflector on the opposite side of the electrodes from the window. Or, the noise reduction means includes both an absorbing medium on the opposite side of the electrode from the window and a deflector disposed between the electrodes and the absorbing medium. Other embodiments, however are possible.
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patent: 5399931 (1995-03-01), Roberts
patent: 5721465 (1998-02-01), Roberts
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Advertisement 1100 Series High Stability Short Arc Xenon Flashlamps, EG&G Optoelectronics 2/94.
Advertisement, 1100 Series FlashPacs, EG&G Optoelectronics, 1/97.
Advertisement, 1100 Series Lite-Pac Trigger Modules, EG&G Optoelectronics 2/94.
Advertisement, 1100 Series FX-1160, High Output Short Arc Xenon Flashlamp With Internal Reflector, EG&G Optoelectronics 10/96.
Advertisement, LabPac PS 1200 Laboratory Flashlamp Power Supply, EG&G Optoelectronics 1/97.
Advertisement, 1100 Series Power Supplies, EG&G Optoelectronics 2/94.
Advertisement, 1100 Series Short Arc Flashlamps, Trigger Modules and Power Supplies, EG&G Optoelectronics 10/1997.
Kirk Teska Iandiorio & Teska
Patel Nimeshkumar D.
PerkinElmer Inc.
Williams Joseph
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