LIGHTING FIXTURE WITH COLLIMATING LENS

Abstract: A lighting fixture for a gas discharge lamp is claimed. The lighting fixture includes an outer housing (10), at least one gas discharge lamp (14) and a collimating lens (20). The collimating lens includes a plurality of elongated spaced ridges, wherein the lens has a substantially symmetrical curved shape.

Description: LIGHTING FIXTURE WITH COLLIMATING LENS This patent application claims priority of United States Provisional Patent Application No. 60/059,212, filed on September 18, 1997. BACKGROUND OF THE INVENTION This invention relates to lighting fixtures with collimating lenses, and more particularly to gas discharge lamp fixtures that provide high efficiency light sources to conserve power resources and reduce dissipation as heat. Gas discharge lamps are highly efficient sources of light energy. Gas discharge lamps are typically formed of gas filled vessels having electrodes. In order to power a gas discharge lamp, a high voltage is applied across the electrodes at a high frequency. Gases within the tube become ionized as they are excited by high energy radiation. Light output of the gas discharge lamp is thus directly related to the input power signal characteristics. Since gas discharge lamps have a high illumination intensity, the energy emitted at the output surface of the lighting fixture adjacent the energy source is brighter than the light energy emitted from other portions of the output surface of the lighting fixture. Thus, it is desirable to have a relatively uniform illumination intensity radiating from the lighting fixture. SUMMARY OF THE INVENTION In a preferred embodiment of the present invention, the lighting fixture includes an outer housing, at least one elongated gas discharge lamp supported within the outer housing, and a collimating lens disposed above the lamp. The collimating lens preferably has the shape of a truncated cylinder, and has a plurality of adjacent ridges thereon which collimate the light energy output by the lamp. The lens preferably has a substantially symmetric curved shaped in a plane transverse to the longitudinal axis of the lamp and to the longitudinal axis of the lens. In a preferred embodiment, the adjacent ridges of the collimating lens create a plurality of adjacent peaks and valleys, with slopes or side surfaces therebetween. A centrally-disposed region of the lens has a Fresnel section to collimate light emitted from the central region of the lens, and to decrease the likelihood that such light will be internally reflected back into the lighting fixture. Each of the elongated ridges acts like a prism, and opposite sides or slopes of a single ridge may be of different lengths. The lighting fixture also includes a reflector disposed behind each lamp, a cavity that receives a ballast, and a sealed, mechanically-isolated switch. The reflector may be of the specula or diffused type. The lighting fixture may be sealed, and may be covered with a removable cover plate that can be changed to coordinate the lighting fixture with the style and color of the location in which it is placed. The use of the collimating lens results in the collimation of almost all of the light emitted by the lamp, making the lamp approximately 30 percent more efficient while maintaining a low profile for the lamp. One suitable collimating lens is designed by TIR Technologies, Inc. (Teledyne), California and marketed under the name TIR LENS SYSTEM. Several such collimating lenses are described in: U.S. Patent No. 4,337,759 issued July 6, 1982; U.S. Patent No. 5,404,869 issued April 11, 1995; U.S. Patent No. 5,613,769 issued March 25, 1997; and U.S. Patent No. 5,655,832, all of these patents being incorporated by reference herein. Of course, a translucent member without a TIR LENS SYSTEM may be used as well. In one embodiment, the invention includes one or more elongated, substantially linear lamps disposed within a substantially rectangular housing. In another embodiment, the lighting fixture includes at least one curved or circular lamp, a circular outer housing, and a circular lens. The lens includes a plurality of concentric ring-like peaks and valleys, with a centrally-disposed concave section disposed radially inward from the rings. The rings and the centrally-disposed concave section collimate substantially all of the light emitted by the light source. Again, the lighting fixture is provided with a reflector adjacent to the light source on a side opposite to the lens to reflect all available light toward the lens. DETAILED DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of a rectangular lighting fixture according to the present invention having two elongated, linear lamps. FIG. 2 is a cross-sectional end view of the lighting fixture, taken along line 2-2 of FIG. 1. FIG. 3 is a side end view of the lighting fixture, taken along line 3-3 of FIG. 1. FIG. 4 is a top plan view of a circular lighting fixture according to the present invention. FIG. 5 is a side cross-sectional view of the lighting fixture, taken along line 5-5 of FIG. 4. FIG. 6 is a side end view of the lighting fixture, taken along line 6-6 of FIG. 4. FIG. 7 is a top plan view of a rectangular lighting fixture according to the present invention having a elongated liner lamp. FIG. 8 is a cross-sectional end view of the lighting fixture, taken along line 8-8 of FIG. 7. FIG. 9 is a side end view of the lighting fixture, taken along line 9-9 of FIG. 7. FIG. 10 is a schematic diagram of a collimating lens which may be used with the present invention. FIG. 11 is a schematic diagram of another collimating lens which may be used with the present invention. In FIGS. 1 and 2, outer housing 10 includes a support 12 for two substantially parallel elongated lamps 14. Cavity 16 is adapted to receive a ballast or other control circuitry. The lighting fixture includes magnetic switches 18 and 19 to actuate each lamp 14. When switch 18 or 19 is actuated, power is supplied through ballasts 20 and 22, respectively, to each of the lamps 14. A control signal may be used between switches 18 and 19 to actuate the other switch. As best shown in FIG. 2, each of lamps 14 has associated therewith a collimating lens 20 comprised of a plurality of adjacent elongated ridges with valleys therebetween. A centrally-disposed region 21 of each lens 20 has a Fresnel section to collimate light emitted from the central region of the lens and to decrease the likelihood that such light will be internally reflected back into the lighting fixture. Thus, each of the elongated ridges acts like a prism. Depending upon the angle by which light emitted from each of the lamps 14 hits the prisms, the light may be internally reflected until hitting the prisms at such an angle that light is permitted to be emitted through the prisms. The lighting fixture also includes a reflector 23 disposed behind each of lamps 14. Reflector 23 reflects light emitted from each of lamps 14 back towards each collimating lens 20. By controlling the angle by which light is emitted from the prisms, the emitted light is collimated and therefore more even in appearance. FIG. 3 is a side end view of the lighting fixture of FIG. 1. The lighting fixture may be sealed, and may be covered with a removable cover plate or bezel 25 that can be changed to coordinate the lighting fixture with the style and color of the location in which it is placed. In FIG. 4, the lighting fixture includes a substantially circular housing 22 having one or more curved tubular lamps 24. Each of the lamps has an adjacent reflector 26 that reflects back substantially all light emitted from the back side of the lamp. The reflector may be made from an acrylic, glass, plastic, or a material of similar properties. A lens 28 has a plurality of concentric rings for collimating the light. A magnetic switch 30 actuates each of lamps 24. Switch 30 is a sealed, mechanically-isolated switch such as the switch described in the pending PCT application to Everbrite, Inc. entitled "Switch for Sealed Lighting Fixtures" which is incorporated herein by reference. The lighting fixture is covered with a removable plate 32 which may be changed to coordinate the lighting fixture according to the style desired. FIG. 5 is a side cross-sectional view of the lighting fixture taken along line 5-5 of FIG. 4. FIG. 6 is a side end view of the lighting fixture taken along line 6-6 of FIG. 4. Both views further illustrate that light may be internally reflected until hitting the prisms at such an angle that light is permitted to be emitted through the prisms. FIG. 7 is a top plan view of a rectangular lighting fixture according to the present invention having a single elongated linear lamp. Similar in structure to FIG. 1, outer housing 100 includes a support 102 for two substantially parallel elongated lamps 104 and 105. A cavity 106 is adapted to receive a ballast or other control circuitry. The lighting fixture includes magnetic switches 108 and 109 which control ballasts 110 and 112. A control signal between switches 108 and 109 may actuate the other switch. FIG. 8 is a cross-sectional end view of the lighting fixture of FIG. 7. The lamp 114 has associated therewith a collimating lens 120 comprised of a plurality of adjacent elongated ridges with valleys therebetween. A centrally-disposed region 121 of the lens 120 has a Fresnel section to collimate light emitted from the central region 121 of the lens and to decrease the likelihood that such light will be internally reflected back into the lighting fixture. The elongated ridges act as a prism and control the angle by which light is emitted from the lens. Accordingly, the emitted light is collimated and has a more uniform output illumination. FIG. 9 is a side end view of the lighting fixture of FIG. 7. FIG. 9 illustrates that the lighting fixture is enclosed in a sealed housing, and is thus protected from the external environment. FIGS. 10 and 11 more clearly depict the profile of the collimating lens used in the present invention. As shown in FIGS. 10 and 11, the lens has a shape of a truncated cylinder. In any case, the lens has a flat or a centrally-disposed Fresnel section for collimating light emitted near the central portion of the lens, and to minimize internal reflection within the lamp. Although several embodiments of the invention have been shown and described, alternate embodiments may be apparent to those skilled in the art. Therefore, the invention is to be limited only to the following claims.

Claims: CLAIMS 1. A lighting fixture for a gas discharge lamp, comprising: an outer housing; at least one elongated gas discharge lamp; and a collimating lens including a longitudinal axis and having a plurality of elongated spaced ridges, said lens also having a substantially symmetrical curved shape in a plane that is transverse to said axis. 2. The lighting fixture of claim 1, wherein said lens substantially has a shape of a truncated cylinder. 3. The lighting fixture of claim 1, wherein said lens further comprises a centrally-disposed concave section. 4. The lighting fixture of claim 1, wherein said housing further comprises a cavity that receives a control circuit. 5. The lighting fixture of claim 1, further comprising: a sealed, magnetically-operated switch. 6. The lighting fixture of claim 1, wherein said lens has a substantially smooth surface. 7. The lighting fixture of claim 6, wherein said ridges are disposed on a secured surface of said lamp that is opposite to said smooth surface. 8. The lighting fixture of claim 1, further comprising: a second elongated lamp; and a second collimating lens including a second longitudinal axis and having a secured plurality of elongated spaced ridges. 9. The lighting fixture of claim 1, wherein said lens has an output side, said fixture further comprising: a reflector disposed adjacent to a second side of said lens that is opposite to said output side. 10. The lighting fixture of claim 1, wherein said lamp has a substantially circular shape, and wherein said ridges are arranged as substantially concentric circles. 11. The lighting fixture of claim 1, wherein said lamp is substantially linear, and wherein said ridges are also substantially linear and substantially parallel to said lamp. 12. The lighting fixture of claim 1, further comprising: a ballast disposed without said housing. AMENDED CLAIMS [received by the International Bureau on 03 March 1999 (03.03.99); original claims 1-12 replaced by new claims 1-11(2 pages)] 1. A lighting fixture, comprising: a low profile housing having a width substantially greater than a height; at least one elongated gas discharge lamp; and a collimating lens disposed on a second side of said lamp opposite said first side, said lens having a plurality of elongated spaced ridges on a first surface, said lens also having a cross section of a truncated cylinder. 2. The lighting fixture of claim 1, wherein said lens further comprises a centrally-disposed concave section. 3. The lighting fixture of claim 1, wherein said lens also includes a smooth surface opposite to said first surface. 4. The lighting fixture of claim 1, wherein said lamp is linear and said ridges are parallel to each other. 5. The lighting fixture of claim 1, wherein said lamp is circular and said ridges form substantially concentric circles. 6. The lighting fixture of claim 1, wherein said housing further comprises a cavity that receives a control circuit. 7. The lighting fixture of claim 1, wherein said housing is sealed, and wherein said lighting fixture further comprises: a sealed, magnetically-operated switch. 8. The lighting fixture of claim 1, further comprising: a second elongated lamp disposed within said housing; and a second collimating lens, said second lens having a plurality of elongated spaced ridges on a surface thereof, said second lens also having a cross section of a truncated cylinder. 9. The lighting fixture of claim 1, further comprising: a reflector disposed adjacent said lamp. 10. The lighting fixture of claim 8, wherein said housing is sealed, and further comprising: a sealed magnetically-operated switch. 11. The lighting fixture of claim 1, further comprising: a removable cover plate disposed external of said housing.

Inventors: KARSTEN ROBERT, MOHACSI FERENC, MONDLOCH MICHAEL, MUNNS DOC, PYNE HARRY, VENIERIS GEORGE, KARSTEN, ROBERT, MOHACSI, FERENC, MONDLOCH, MICHAEL, MUNNS, DOC, PYNE, HARRY, VENIERIS, GEORGE
Applicants: EVERBRITE INC, KARSTEN ROBERT, MOHACSI FERENC, MONDLOCH MICHAEL, MUNNS DOC, PYNE HARRY, VENIERIS GEORGE, EVERBRITE, INC., KARSTEN, ROBERT, MOHACSI, FERENC, MONDLOCH, MICHAEL, MUNNS, DOC, PYNE, HARRY, VENIERIS, GEORGE
Application year: 1998
Main classification: F21S3
IPC codes: F21S8, F21V5, F21V23, F21Y103