Optical: systems and elements – Glare or unwanted light reduction
Reexamination Certificate
2000-06-27
2001-06-12
Sikder, Mohammad (Department: 2872)
Optical: systems and elements
Glare or unwanted light reduction
C359S605000, C359S609000, C359S610000, C359S613000
Reexamination Certificate
active
06244715
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to a window glare-reducing assembly for reducing the amount of interior light reflected into a driver's eyes from the windshield of a mass transit vehicle as well as the amount of passenger-perceived glare reflected from side windows of a mass transit vehicle.
INVENTION BACKGROUND
Some mass transit vehicle interior lighting fixtures are known to include louvers or fins spaced axially along the length of an elongated cylindrical light source such as a fluorescent lamp. The louvers extend laterally from the lamps to direct light laterally into passenger seating areas and away from the windshield.
For example, U.S. Pat. No. 2,099,451, issued Nov. 16, 1937 to Schepmoes (the Schepmoes patent), discloses a lighting fixture intended for use in “railroad cars and the like” that includes a plurality of parallel louvers or fins spaced axially along the length of a fluorescent lamp. In addition, U.S. Pat. No. 4,717,992, issued Jan. 5, 1988 to Bartenbach et al. (the Bartenbach et al. patent), discloses a lighting fixture that includes a plurality of parallel louvers or fins spaced axially along the length of a fluorescent lamp. Each louver includes a circular hole sized to fit closely around the lamp.
U.S. Pat. No. 2,299,276 to Kirlin (the Kirlin patent) discloses racks of parallel louvers, each louver having a half-circular cutout sized to receive a fluorescent lamp. Each rack disclosed in the Kirlin patent includes a pair of C-shaped wire clips for clipping the louver racks onto the fluorescent lamp. In the louvers disclosed in the Shepmoes, Bartenbach et al. and Kirlin patents are configured to be supported directly on a fluorescent lamp.
What is needed is a window glare-reducing assembly that allows louvers to be mounted on and removed from an elongated cylindrical light source more quickly and easily.
INVENTION SUMMARY
According to the invention, a window glare-reducing assembly is provided for reducing the amount of glare reflected from a window of a mass transit vehicle by interior vehicle lighting. The assembly includes a first plurality of louvers configured to be supported in an axially spaced-apart disposition along the length of an elongated cylindrical light source. The window glare-reducing assembly also includes a tubular sleeve configured to receive an elongated cylindrical light source such as a fluorescent lamp. The first plurality of louvers is supported on the sleeve in an axially spaced-apart disposition. This allows each louver of the first plurality of louvers to fit closely around the cylindrical light source while simplifying installation and removal of the louvers and installation and replacement of cylindrical light sources that the louvers are supported on. Therefore, a window glare-reducing assembly constructed according to the invention is both easier to install and remove, and allows lamps to be replaced more easily.
According to another aspect of the invention, the sleeve comprises a plastic material, a transparent material and/or a colored material. The color and transparency of the sleeve material may be selected by a customer to complement existing interior color schemes, to control light dispersion, to affect passenger moods and/or to cause passengers to associate a certain color with the particular transport company that uses it.
According to another aspect of the invention, a support shaft is connected to each louver of the first plurality of louvers. The support shaft holds the louvers together making them easier to install on and remove from the tube. The support shaft also serves to stabilize the relative positions and attitudes of the louvers connected to it.
According to another aspect of the invention, the first plurality of louvers and the first support shaft are integrally formed as a single unitary piece. Forming the louvers and shaft as a single unitary piece eliminates the need to manufacture and assembly multiple parts.
According to another aspect of the invention, the assembly includes at least one additional plurality of louvers configured to be supported in an axially spaced-apart disposition along the length of an elongated cylindrical light source and a second support shaft connected to each louver of the additional plurality of louvers. The first support shaft is configured to interconnect with the second support shaft in an end-to-end disposition. Shorter lengths of louvered shafts are easy to manufacture and can easily be assembled end-to-end to cover whatever length of fluorescent tube is being used in a particular lighting fixture.
According to another aspect of the invention, one of the first and second support shafts includes an axial counter bore at one end. The other of first and second support shafts includes a complementary axially extending post at one end configured to be received into the axial counter bore. This pin-and-socket arrangement maintains alignment between adjacent lengths of louvered shafts providing aesthetically pleasing visual continuity.
According to another aspect of the invention, each louver includes a circular through-hole. The circular through holes are configured and coaxially aligned to receive the tubular sleeve. The holes allow the louvers to extend completely around the circumference of the lamp they are supported on thereby directing a maximum amount of light emitted from the host lamp.
According to another aspect of the invention, the louvers comprise non-reflective surfaces to further reduce non-lateral light emissions by absorbing rather than reflecting light.
According to another aspect of the invention, the louvers comprise translucent material to reduce the magnitude and harshness of non-lateral light emissions.
According to another aspect of the invention, the louvers comprise colored material to complement existing interior color schemes, to control light dispersion, to affect passenger moods and/or to cause passengers to associate a certain color with the particular transport company that uses it.
According to another aspect of the invention, the louvers are disposed parallel to each other to direct light evenly along the length of the vehicle.
According to another aspect of the invention, the louvers are disposed perpendicular to the support shaft to direct light exclusively in a lateral direction relative to the lamp.
According to another aspect of the invention, the louvers are angled relative to the support shaft and lamp to direct light toward a predetermined portion of the passenger compartment or away from a predetermined portion of the passenger compartment.
According to another aspect of the invention, the louvers are spaced apart by a distance that provides an interior illumination level of 15 foot-candles at each reading plane at each seat location within a vehicle to be illuminated, where the entire length of each elongated cylindrical light source mounted within the vehicle is disposed within the assembly and a plurality of like assemblies having identically spaced louvers. (Each reading plane is defined as a one square foot plane inclined at a 45 degree angle 33″ above a floor of the vehicle and 22″ in front of a seat back of one of the seats.) This insures that the lighting system meets minimum industry standards for mass transit vehicle interior lighting.
According to another aspect of the invention, each louver includes an inside edge configured to conform generally to the interior contours of a lamp housing in an interior light fixture. The conforming inside edge prevents light from escaping between the inside edge and the lamp housing and provides maximum louver surface area for light deflection.
According to another aspect of the invention, each louver includes an outside edge configured to conform generally to the interior contours of an interior light fixture lens. The conforming outside edge provides a maximum louver surface area for light deflection within the confines of the lens.
According to another aspect of the invention, the louvers are black in color to increase light absorption and to min
Domas Ben V.
McCauley Alvin D.
Reising Ethington Barnes Kisselle Learman & McCulloch PC
Sikder Mohammad
Transmatic, Inc.
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