Illumination – Light source and modifier – Including reflector
Utility Patent
1999-08-09
2001-01-02
Sember, Thomas M. (Department: 2875)
Illumination
Light source and modifier
Including reflector
C362S304000, C362S305000, C362S348000, C362S302000, C362S347000
Utility Patent
active
06168293
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to the lamp arts. More particularly, this invention relates to a reflector for use in reflector spot PAR reflector lamps and will be described with particular reference thereto. It should be appreciated that the invention is also applicable to reflective lamps employing a variety of light sources.
The reflector lamps of the present invention are particularly well suited for use in spot lighting, such as headlamps, display lighting, and the like. Examples of typical reflector lamps include General Electric's PAR 30, PAR 38, and PAR 64 lamps. PAR is the commonly accepted acronym for “parabolic aluminum reflector.” Other commercially available reflector lamps may also benefit from aspects of the present invention. U.S. Pat. Nos. Re.30,832; 3,010,045; 4,021,659; 4,804,878; 4,833,576; 4,855,634; 4,959,583; and 5,199,878 describe reflector lamps and methods of their manufacture. U.S. Pat. No. 4,420,800 discloses reflectors with a combination of confocal spherical and parabolic shaped portions. U.S. Pat. No. 4,494,176 describes a PAR lamp with a faceted parabolic reflector surface. The filament is at the focal point of the parabolic portion but not of a small adjacent neck portion of the reflector resulting in wasted light due to reflections outside the beam angle. U.S. Pat. No. 5,199,787 describes a reflector lens with curved, radial flutes.
FIG. 1
shows a conventional parabolic reflector A.
FIG. 2
shows a fluted parabolic reflector B.
It has now been found that while flutes on the top of the reflector are useful in spreading filament image within the beam angle, flutes at the bottom (or neck area) of the reflector create an undesirably large spread.
For a good spot reflector lamp it is desirable to have as much light as possible emitted in a beam of 0-5° from the axis of the lamp. Light emitted in the 6-10° range is essentially wasted. However too much light in the center (approximately 0-1°) is also undesirable, leading to uneven light distribution and burn out.
The present invention provides for a new and improved reflector lamp, which overcomes the above-reference problems and others.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, a reflector lamp is provided. The lamp includes first and second reflective sections. The first reflective section has a generally parabolic shape and a focal point and having an axis passing through the focal point. A plurality of flutes occupying a major portion of the first reflective section. The second reflective section has a generally concave shape which is substantially free of flutes and a focal point which is substantially coincident with the focal point of the first reflective section. The second reflective section is joined to the first reflective section. A light source is approximately centered at the focal point of the first reflective section and the focal point of the second reflective section.
In accordance with another aspect of the present invention, a method of forming a beam of light in which a majority of the light is within a 6° angle from an axis through the beam and is substantially free of a central hot spot is provided. The method includes providing a light source at the focal point of first and second reflective surfaces. The first reflective surface has a plurality of flutes. The second reflective surface is free of flutes. The method further includes reflecting a first portion of light emitted from the light source from the first reflective surface, the flutes distributing the light to minimize the hot spot and reflecting a second portion of light emitted from the light source from the second reflective surface, the non-fluted second reflective surface reflecting the light primarily within the 6° angle from the axis through the beam.
One advantage of the present invention is that light is emitted within a desired beam angle of about 5 degrees.
Another advantage of the present invention is that a smooth beam is provided with a minimized hot spot effect.
Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiments.
REFERENCES:
patent: 4021659 (1977-05-01), Wiley
patent: 4277821 (1981-07-01), Sassmannshausen
patent: 4420800 (1983-12-01), Van Horn
patent: 4447865 (1984-05-01), VanHorn et al.
patent: 4494176 (1985-01-01), Sands et al.
patent: 4506316 (1985-03-01), Thiry et al.
patent: 4959583 (1990-09-01), Arsena et al.
patent: 5177396 (1993-01-01), Gielen et al.
patent: 5199787 (1993-04-01), King et al.
Brann Jacob
Collins Edward Joseph
Lieszkovszky Laszlo Viktor
Skilskyj Ludwig
Alavi Ali
Fay Sharpe Fagan Minnich & McKee LLP
General Electric Company
Sember Thomas M.
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