Light fixture for indirect asymmetric illumination with LEDs

Abstract

A light fixture optimized for directional lighting, including LED lighting, includes a fixture housing, further including a lighting element shelf and a window opening; a reflector, which is configured with a special parabolic shape, a lighting element which is mounted on an inside surface of the lighting element shelf, such that light emitted from the lighting element will reflect at least one time on the reflector, before exiting the light fixture via the window opening as a wide and uniform field of asymmetric indirect illumination. The light fixture can be configured in versions suitable for wall illumination, conference room illumination, ceiling illumination, ground surface illumination, and related illumination applications for interior and exterior use.

Claims

1. A light fixture, comprising: a) a fixture housing, which is closed in a rear side, and comprises a window opening in a front side, bordered along one side by a side panel, to which is connected a lighting element shelf; b) a reflector, configured with a parabolic shape such that the reflector extends from a starting edge, such that the reflector is initially substantially asymptotically perpendicular in a cross-sectional plane to the window opening, such that an initial angle between the reflector and the window opening is in a range of −5 to +5 degrees from a 90 degree perpendicular angle, the reflector thereafter extending in a parabolic curve towards the rear side of the light fixture, reaching an apex, from which the curve continues a parabolic curve, from the apex to an ending point, wherein only the starting edge of the reflector is substantially asymptotically perpendicular in the cross-sectional plane to the window opening c) at least one lighting element, mounted on the inside surface of the lighting element shelf, inside the fixture housing, wherein the lighting element provides directional light, in direction from a plane of an inner surface of the lighting element towards the rear side; and d) an angled ledge, which is connected to an inner edge of the lighting element shelf, and protrudes inwards at an angle, in a range of 0 to 90 degrees, whereby the angled ledge shields direct light from the lighting element; wherein the angled ledge is reflective on an inner side, such that light from the lighting element directed on to the angled ledge, is reflected on to the reflector, and is eventually emitted via the window opening as indirect light; such that light emitted from the lighting element, will reflect at least one time on the reflector, before exiting the light fixture via the window opening.

2. The light fixture of claim 1, wherein the reflector is further configured with a short parabolic shape, such that the apex is configured in a position on the parabolic curve at 20-30% of a horizontal projection length in a plane of the window opening, from the starting edge of the cross-sectional reflector curve to the ending edge, with a reflector depth to reflector width ratio of at most 1:3.

3. The light fixture of claim 1, wherein the reflector is further configured with an elongated parabolic shape, such that the apex is configured in a position approximately at 20-30% of a horizontal projection length in a plane of the window opening, from the starting edge of the cross-sectional reflector curve to the ending edge, with a reflector depth to reflector width ratio of more than 1:3.

4. The light fixture of claim 1, wherein the angled ledge is adjustable.

5. The light fixture of claim 1, wherein the lighting element is a light emitting diode lighting assembly.

6. The light fixture of claim 1, further configured with two reflective end plates attached to the inside of each side of the fixture housing, and connected to each end of the reflector.

7. The light fixture of claim 1, wherein the light fixture is further configured with a regressed lens that covers the window opening.

8. The light fixture of claim 1, wherein the lighting element shelf is in plane with the window opening, and parallel to the window opening.

9. The light fixture of claim 1, wherein an inner surface of the lighting element shelf is recessed, such that the inner surface is further inside the fixture housing, as compared to the window opening plane.

10. The light fixture of claim 1, wherein an inner surface of the lighting element shelf is angled in a cross-sectional plane, such that the cross-sectional inner surface is not parallel with the cross-sectional window opening.

11. The light fixture of claim 10, wherein an angle of the inner surface is in a range of −20 to 20 degrees.

12. The light fixture of claim 10, wherein an angle of the lighting element shelf is adjustable.

13. The light fixture of claim 1, wherein an inner surface of the lighting element shelf is parallel with a plane of the window opening.

14. A light fixture, comprising: a) a fixture housing, which is closed in a rear side, and comprises a window opening in a front side, bordered along one side by a side panel, to which is connected a lighting element shelf; b) a reflector, configured with a parabolic shape such that the reflector extends from a starting edge, such that the reflector is initially substantially asymptotically perpendicular in a cross-sectional plane to the window opening, such that an initial angle between the reflector and the window opening is in a range of −5 to +5 degrees from a 90 degree perpendicular angle, the reflector thereafter extending in a parabolic curve towards the rear side of the light fixture, reaching an apex, from which the curve continues a parabolic curve, from the apex to an ending point, wherein only the starting edge of the reflector is substantially asymptotically perpendicular in the cross-sectional plane to the window opening c) at least one lighting element, mounted on the inside surface of the lighting element shelf, inside the fixture housing, wherein the lighting element provides directional light, in direction from a plane of an inner surface of the lighting element towards the rear side; and d) an angled ledge, which is connected to an inner edge of the lighting element shelf, and protrudes inwards at an angle, in a range of 0 to 90 degrees, whereby the angled ledge shields direct light from the lighting element; wherein the angled ledge is adjustable; such that light emitted from the lighting element, will reflect at least one time on the reflector, before exiting the light fixture via the window opening.

15. A light fixture, comprising: a) a fixture housing, which is closed in a rear side, and comprises a window opening in a front side, bordered along one side by a side panel, to which is connected a lighting element shelf; b) a reflector, configured with a parabolic shape such that the reflector extends from a starting edge, such that the reflector is initially substantially asymptotically perpendicular in a cross-sectional plane to the window opening, such that an initial angle between the reflector and the window opening is in a range of −5 to +5 degrees from a 90 degree perpendicular angle, the reflector thereafter extending in a parabolic curve towards the rear side of the light fixture, reaching an apex, from which the curve continues a parabolic curve, from the apex to an ending point, wherein only the starting edge of the reflector is substantially asymptotically perpendicular in the cross-sectional plane to the window opening c) at least one lighting element, mounted on the inside surface of the lighting element shelf, inside the fixture housing, wherein the lighting element provides directional light, in direction from a plane of an inner surface of the lighting element towards the rear side; and d) two reflective end plates attached to the inside of each side of the fixture housing, and connected to each end of the reflector; such that light emitted from the lighting element, will reflect at least one time on the reflector, before exiting the light fixture via the window opening.

16. A light fixture, comprising: a) a fixture housing, which is closed in a rear side, and comprises a window opening in a front side, bordered along one side by a side panel, to which is connected a lighting element shelf; b) a reflector, configured with a parabolic shape such that the reflector extends from a starting edge, such that the reflector is initially substantially asymptotically perpendicular in a cross-sectional plane to the window opening, such that an initial angle between the reflector and the window opening is in a range of −5 to +5 degrees from a 90 degree perpendicular angle, the reflector thereafter extending in a parabolic curve towards the rear side of the light fixture, reaching an apex, from which the curve continues a parabolic curve, from the apex to an ending point, wherein only the starting edge of the reflector is substantially asymptotically perpendicular in the cross-sectional plane to the window opening and c) at least one lighting element, mounted on the inside surface of the lighting element shelf, inside the fixture housing, wherein the lighting element provides directional light, in direction from a plane of an inner surface of the lighting element towards the rear side; wherein an inner surface of the lighting element shelf is angled in a cross-sectional plane, such that the cross-sectional inner surface is not parallel with the cross-sectional window opening; such that light emitted from the lighting element, will reflect at least one time on the reflector, before exiting the light fixture via the window opening.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective partially exploded view of a LED light fixture for indirect asymmetric illumination, according to an embodiment of the invention.

(2) FIG. 2 is a cross-sectional side view of a LED light fixture for indirect asymmetric illumination, according to an embodiment of the invention.

(3) FIG. 3 is a cross-sectional side view illustrating illumination of a wall by a LED light fixture, according to the embodiment of the invention shown in FIG. 2.

(4) FIG. 4 is a cross-sectional side view of a LED light fixture for indirect asymmetric illumination, according to an embodiment of the invention.

(5) FIG. 5 is a cross-sectional side view illustrating illumination of a person by a LED light fixture, according to the embodiment of the invention shown in FIG. 4.

(6) FIG. 6 is a cross-sectional side view of a LED light fixture for indirect asymmetric illumination, according to an embodiment of the invention.

(7) FIG. 7 is a cross-sectional side view illustrating illumination of a ceiling by a cove mounted LED light fixture, according to the embodiment of the invention shown in FIG. 6.

(8) FIG. 8 is a cross-sectional side view of a LED light fixture for indirect asymmetric illumination, according to an embodiment of the invention.

(9) FIG. 9 is a cross-sectional side view illustrating illumination of an exterior floor surface by a LED light fixture, according to the embodiment of the invention shown in FIG. 8.

(10) FIG. 10 illustrates a light intensity distribution for a LED light fixture for wall illumination, according to an embodiment of the invention.

(11) FIG. 11 illustrates a light intensity distribution for a LED light fixture for video conferencing, according to an embodiment of the invention.

(12) FIG. 12 illustrates a light intensity distribution for a LED light fixture for cove illumination, according to an embodiment of the invention.

(13) FIG. 13 illustrates a light intensity distribution for a LED light fixture for exterior ground surface illumination, according to an embodiment of the invention.

DETAILED DESCRIPTION

(14) Before describing the invention in detail, it should be observed that the present invention resides primarily in a novel and non-obvious combination of elements and process steps. So as not to obscure the disclosure with details that will readily be apparent to those skilled in the art, certain conventional elements and steps have been presented with lesser detail, while the drawings and specification describe in greater detail other elements and steps pertinent to understanding the invention.

(15) The following embodiments are not intended to define limits as to the structure or method of the invention, but only to provide exemplary constructions. The embodiments are permissive rather than mandatory and illustrative rather than exhaustive.

(16) In the following, we describe the structure of an embodiment of a light fixture for indirect asymmetric illumination 100 with reference to FIG. 1, in such manner that like reference numerals refer to like components throughout; a convention that we shall employ for the remainder of this specification.

(17) In an embodiment, FIG. 1 shows a partially exploded perspective view of a light fixture 100. The light fixture 100 is shown in a downward facing orientation, such as for installation in a ceiling. The fixture housing 110 is closed on top and provides a large light window opening at the bottom bordered along one side by a side panel 112 connected along its edge with a lighting element shelf 114, which is in plane with the window opening 211 (illustrated in FIG. 2), shown in dotted line. One or more lighting elements (not visible in FIG. 1) can be mounted on the top surface of the lighting element shelf 114, inside the fixture housing 110.

(18) The fixture housing 110 can be attached to the framing of a building by a mounting bracket 116. Once installed, the housing's leading bottom edge 117 can be set flush with the lower surface of the ceiling, or another surface of a building or structure. An electrical connection plate 118 further including a pair of knockout holes is located on the outside of fixture housing 110. Mounted inside the fixture housing 110 can be a ballast/driver 120, shown in dashed lines, for driving one or more lighting elements.

(19) The reflector 130, shown removed from the fixture housing 110, can be made from a sheet of an appropriate material, which can be a plastic or a fiber composite, or a metal such as high purity aluminum formed into a special parabolic curved cross-sectional shape as shown. The reflector's ending edge can be formed with two bends to provide a Z-shaped cross section with an offset mounting flange 132 extending outwardly as shown, and the reflector ending edge can be straight, and can include at least one clearance notch 134, as shown. The reflector 130 can include other notches or cutouts, as required to provide clearance during installation or removal of the reflector 130. The formed reflector 130 can be manufactured in one piece and be spring loaded. It can snap into the fixture housing 110 without the need of tools.

(20) A trim frame 140, for hard surface installations, can include flanges extending outward on all four sides from a four-sided collar portion. The collar portion can be dimensioned to fit around the outside of housing 110, and be held in place by fastening clips 122 attached onto the housing, such that the collar portion is configured with a shape such that it can snap on in place by the fastening clips 122. Other variations can be configured for installation in T-bar ceilings and surface/pendant installations.

(21) In a related embodiment, FIG. 2 shows a cross sectional view of a light fixture 100, wherein the reflector 130 can be configured with a short parabolic shape, such that the reflector 130 extends from the starting edge 234, such that the reflector 130 is initially substantially asymptotically perpendicular in the cross-sectional plane to a window opening 211, such that an initial angle between the reflector 130 and the window opening 211 is in a range of −5 to +5 degrees from a 90 degree perpendicular angle, thereafter extending in a parabolic curve towards the rear panel 213 of the light fixture, reaching an apex 236, after 20-30% 250 of the horizontal projection length or reflector width 244 in the plane of the window opening, from the starting edge 234 of the cross-sectional reflector 130 curve to the ending edge 232, from where the curve continues an elongated parabolic curve, from the apex 236 to the ending point 232. As shown on FIG. 2, a short parabolic shape of the reflector 130 can be configured with a reflector depth 242 to width 244 ratio of the reflector 130 of equal to or less than 1:3, wherein the reflector depth 242 is the length of the shortest straight line in the cross-sectional plane from the apex 236 to the straight line between the starting and ending points 234 232, and the reflector width is the length of the straight line between the starting and ending points 234 232. A short parabolic shape of the reflector 130 can have depth to width ratio of equal to or less than 1:3, such as for example, as shown in FIG. 2, approximately 1:2.5, 1:2, or even 1:1 or less.

(22) As shown on FIG. 2, lighting elements 228 can be positioned on the top surface of the lighting element shelf 114, inside the fixture housing 110, in the plane of the window opening, from the starting edge 234 of the cross-sectional reflector 130 curve to the ending edge 232, whereby the lighting elements 228 are effectively shielded from direct visibility, such that all light is transmitted indirectly via the reflector 130, as shown by light paths in dotted lines.

(23) In a related embodiment, the light fixture 100 can further include an angled ledge 204, which is connected to an inner edge of the lighting element shelf 114, and protrudes inwards at an angle, which can be fixed at an angle in a range of 0 to 90 degrees. In FIG. 2, the angled ledge 204 is shown protruding at approximately 45 degrees. The angled ledge 204 can serve to improve shielding of direct light from the edge of the lighting elements 228.

(24) In a related embodiment, the angled ledge 204 can be reflective on the inner side, such that light from the lighting elements 228 is reflected back on to the reflector 130, and is eventually emitted from the light fixture 100 as indirect light.

(25) In a related embodiment, the angled ledge 204 can be adjustable such that the angle can be adjusted between 0 and 90 degrees.

(26) FIG. 3 illustrates the embodiment of FIG. 2 mounted into a ceiling 302 and directed to an adjacent wall 304 and a floor 306, such that light emitted from the lighting elements 228 is “washed” on to the wall 304 and the floor 306.

(27) All light paths, as shown on FIG. 3, represent indirect, reflected light. The design provides optimum uniformity of lighting on the surface being illuminated. The light paths 312 and 314 represent the boundaries of reflected light. The light fixture can be configured in a plurality of sizes and reflector shapes for positioning at varying distances from the wall 304, thereby providing uniform lighting on the wall 304.

(28) FIG. 10 illustrates the light intensity distribution from the light fixture 100 installed in a ceiling. Numeric values in FIG. 10 indicate light intensity readings in foot-candles, in a position on a wall 1000, specified by the center point of a numeric value, as distributed over a 20′ width 1002 by 8 foot height 1004 wall 1000; with the light fixture 100 installed 3′ from the wall.

(29) In a related embodiment, FIG. 4 shows a cross sectional view of a light fixture 400 for illumination of a conference room, wherein the reflector 430 is shown configured with an elongated parabolic shape, such that the reflector 430 extends from the starting edge 434, such that the reflector 430 is initially substantially asymptotically perpendicular in the cross-sectional plane to a window opening 411, such that an initial angle between the reflector 430 and the window opening 411 is in a range of −5 to +5 degrees from a 90 degree perpendicular angle, thereafter extending in a parabolic curve towards the rear panel 413 of the light fixture 400, reaching an apex 436, after approximately 20-30% 450 of the horizontal projection length or reflector width 444 in the plane of the window opening, from the starting edge 434 of the cross-sectional reflector 430 curve to the ending edge 432. As shown on FIG. 4, an elongated parabolic shape of the reflector 430 can be configured with a reflector depth 442 to width 444 ratio of the reflector 430 of more than 1:3, wherein the reflector depth 442 is the length of the shortest straight line in the cross-sectional plane from the apex 436 to the straight line between the starting and ending points 434 432, and the reflector width is the length of the straight line between the starting and ending points 434 234. An elongated parabolic shape of the reflector 430 can have depth to width ratio of more than 1:3, such as for example, as shown in FIG. 4, approximately 1:3.7, 1:4, or even 1:6 or more.

(30) As shown the upper surface of the lighting element shelf 114 can be elevated such that the lighting elements 228 are higher than the plane of the window opening.

(31) FIG. 5 illustrates the embodiment of FIG. 4 mounted into a ceiling 502, such that the light fixture 400 illuminates a person 560 in a room.

(32) In a related embodiment, a plurality of light fixtures 400 can be installed in the ceiling of a video conference meeting room, such that the light fixtures 400, provides uniform illumination of the participants in a video conference.

(33) FIG. 11 illustrates the light intensity distribution on the face of a video conference participant, as emitted from the light fixture 400 installed in a ceiling. Numeric values in FIG. 11 Indicate light intensity readings in foot-candles, as distributed over the face of the video conference participant, with the light fixture 400 installed 4′ in front of the face and pointed in the direction of the participant's face, positioned at a location optimum to the height of the ceiling, such that the primary light distribution is at eye level 4′ above the floor level 1102.

(34) FIG. 6 illustrates a light fixture 600 for cove illumination, as an inverted configuration of the embodiment of FIG. 1.

(35) FIG. 7 illustrates the embodiment of FIG. 6 mounted in a cove 702, such that the light fixture 600 can illuminate a ceiling 704.

(36) In a related embodiment, a plurality of light fixtures 600 can be installed in the cove in a room, such that the light fixtures 600, provides uniform illumination of the ceiling.

(37) FIG. 12 illustrates the light intensity distribution on a ceiling, as emitted from the light fixture 600 for cove illumination. Numeric values in FIG. 12 indicate light intensity readings in foot-candles, as distributed over the ceiling in units of one foot, with the light fixture 600 installed in a cove 3′ below ceiling and pointed in the direction of the ceiling.

(38) In a related embodiment, FIG. 8 shows a cross sectional view of a light fixture 800 for exterior ground surface illumination, wherein the reflector 830 is shown configured with a short parabolic shape, such that the reflector 830 extends from the starting edge 834, such that the reflector 830 is initially substantially asymptotically perpendicular in the cross-sectional plane to a window opening 811, such that an initial angle between the reflector 830 and the window opening 811 is in a range of −5 to +5 degrees from a 90 degree perpendicular angle, thereafter extending in a parabolic curve towards the rear panel 813 of the light fixture 800, reaching an apex 836, after 20-30% of the vertical projection length in the plane of the window opening 811, from the starting edge 834 of the cross-sectional reflector 830 curve to the ending edge 832, from where the curve continues an elongated parabolic curve, from the apex 836 to the ending point 832. The window opening of the light fixture can be covered by a regressed lens 802, thereby providing a more vandal resistant product, while eliminating lamp imaging.

(39) FIG. 9 illustrates a light fixture 800, as shown in FIG. 8, mounted in a wall 902, such that the light fixture 800 can illuminate a ground surface 904.

(40) In a related embodiment, as shown in FIG. 8, an inner surface 815 of the lighting element shelf 814 can be recessed, such that the inner surface is further inside the fixture housing, as compared to the window opening plane 811, shown in dotted line from a cross-sectional view. In addition, the inner surface can be angled in the cross-sectional plane, such that the cross-sectional inner surface is not parallel with the cross-sectional window plane. In FIG. 8, the inner surface is shown with a slightly negative angle, approximately −5 degrees, directing light such that it is tilted towards the side of the lighting fixture. In various embodiments, the angle can configured in a range of −20 to +20 degrees. In various embodiments, the recess of the inner surface can be in a range of 0.5-10 cm. Depending on the size of the light fixture 800, the recess in some cases can be larger than 10 cm.

(41) In a further related embodiment, the angle of the lighting element shelf 814 and/or the inner surface of the lighting element shelf 814 can be adjustable, for example via a pivotal axle.

(42) FIG. 13 illustrates the light intensity distribution on a ground surface, as emitted from the light fixture 800 for exterior ground surface illumination. Numeric values in FIG. 13 indicate light intensity readings in foot-candles, as distributed over the ground surface in units of one foot, with the light fixture 800 installed in a wall by the ground surface, such that the lower part of the light fixture 800 is 2′ above the ground surface.

(43) In a related embodiment, two reflective end plates can be provided, one at each end of the fixture housing 110, attached to the inside of the housing end walls with double-sided adhesive foam material so as to urge the end plates against the two ends of the reflector.

(44) In the various related embodiments, the lighting element 228 can be an LED lighting assembly or a group of LED lighting assemblies. For example, the lighting element can be a distributed array module of the brand PrevaLED™, manufactured by Osram™, such as for example modules of the type 73574PLPG2-BAR-1100-830-280X38-DC.

(45) In various alternative embodiments, other directional lighting element types, styles, and ratings can be used for the lighting element 228.

(46) In various related embodiments, the basic reflector shape can be scaled in size, and fixtures can be supplied in various common nominal lengths such as 18″, 2′, 3′, 4′, etc.

(47) In various related embodiments, the reflector can be configured with a plurality of alternative mating tongue-and-groove type attachment approaches; for example, male members at the two reflector ends could be made to engage female members on the two opposite housing window edges, or female members at the two reflector ends could be made to engage male members on the two opposite housing window edges.

(48) In related embodiments, the fixture housing can be formed entirely from sheet metal such as steel or the major portion surrounding the reflector and defining its mountings can be extruded from aluminum. Alternatively, the fixture housing can be made of plastic or plastic and/or fiber composites.

(49) In related embodiments, the ballast/driver 120, transformer, and associated wiring can be enclosed by a sheet metal baffle plate in compliance with electrical safety requirements.

(50) In related embodiments, LED drivers used to power LED assemblies should provide pure DC (direct current) output to the LED assemblies, such that there is no issue of flicker. Flicker can be caused by the design of the driver's power output having any derivative of 60-hertz cycle AC (alternating current) power delivered to the LED assemblies.

(51) In related embodiments, the reflective surface of the reflector can be highly polished or finely diffused, and can be color-tinted for special effect.

(52) The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention, which fall within the true spirit and scope of the invention.

(53) The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, and all variations, substitutions and changes, which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

(54) Many such alternative configurations are readily apparent, and should be considered fully included in this specification and the claims appended hereto. Accordingly, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and thus, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.