LED Luminaire Tertiary Optic System

Abstract

A lens system for LED based light fixtures having a substantially coplanar array of LED's with a requirement for a wide angle of illumination. And in particular, light fixtures comprising LED lights used in low bay applications.

Claims

1-21. (canceled)

22. A light fixture having reduced glare from a light emitting diode (LED) array comprising: (i) a generally coplanar LED array having a plurality of LEDs each LED generating a quantum of light; (ii) a primary optic configuration receiving each quantum of light and creating a plurality of main beams of light, each main beam of light disposed at a high incidence angle relative to the LED substrate; (iii) a refractive secondary optic configuration disposed adjacent to the primary optic configuration and receiving the plurality of main beams of light from the primary optic configuration; (iv) a tertiary optic configuration being angularly disposed from the primary optic configuration and not immediately adjacent to the LED array and situated to receive and disperse the main beam from each LED; (v) a treatment applied to the tertiary optic configuration, the treatment dispersing the main beam from each LED into a distributed plurality of rays collectively having a substantially batwing distribution with a type V distribution to create a larger, more homogenous luminary element with lower glare than the main beams.

23. The fixture in accordance with claim 22 wherein the angle of incidence is between 50 and 90 degrees.

24. The fixture in accordance with claim 22 wherein the distance between the LED array and the tertiary optic is greater than 2½ inches.

25. The fixture in accordance with claim 22 wherein the mechanism for light dispersion comprises at least one of diffusion and deflection.

26. The fixture in accordance with claim 22 wherein the light fixture comprises a circular shape.

27. The fixture in accordance with claim 26 wherein the inclined cover is substantially hemispherical in shape.

28. The fixture in accordance with claim 22, wherein the treatment comprises a texturing on the tertiary optic configuration.

29. The fixture in accordance with claim 22, wherein the treatment comprises a multiplicity of nano-elements on the tertiary optic configuration.

30. The fixture in accordance with claim 22, wherein the secondary optic configuration comprises at least one lens.

31. The fixture in accordance with claim 22, wherein the type V distribution comprises a wide square distribution or a round distribution.

32. The fixture in accordance with claim 22, wherein the secondary optic configuration comprises a plurality of optics arranged in a planar configuration.

33. A method of reducing glare from a lighting fixture having an array of LEDs, the method comprising: (i) generating a quantum of light from each of a plurality of LEDs in an LED array carried by a substantially coplanar LED substrate; (ii) focusing each quantum of light into a main beam of light through a primary optic configuration such that each main beam of light is disposed at a high incidence angle relative to the LED substrate; (iii) focusing each main beam of light through a refractive secondary optic configuration disposed adjacent to the primary optic configuration; (iv) receiving each main beam of light with a tertiary optic configuration that is angularly disposed from the primary optic and is not immediately adjacent to the LED array; (v) dispersing each main beam of light through the tertiary optic configuration and into a distributed plurality of rays with a treatment applied to the tertiary optic configuration, the plurality of rays collectively having a substantially batwing distribution with a type V distribution, thereby creating a larger, more homogenous luminary element with lower glare than the main beams.

34. The method of claim 33, wherein dispersing each main beam of light through the tertiary optic configuration comprises dispersing each main beam of light with a texturing on the tertiary optic configuration.

35. The method of claim 33, wherein dispersing each main beam of light through the tertiary optic configuration comprises dispersing each main beam of light with a multiplicity of nano-treatments on the tertiary optic configuration.

36. The method of claim 33, wherein the tertiary optic configuration causes a dispersion of light from each of the main beams.

37. The method of claim 33, wherein the batwing distribution pattern comprises at least 70% of light being directed to a zone between 50° and 70° as measured from the fixture nadir.

38. The method of claim 33, wherein the batwing distribution pattern comprises no more than 5% of the light being directed to a zone above 70° as measured from the fixture nadir.

39. The method of claim 37, wherein the batwing distribution pattern comprises no more than 20% of the light being directed to a zone below 40° as measured from the fixture nadir.

40. The method of claim 33, wherein a distance between the LED array and the tertiary optic configuration is greater than 2½ inches.

41. The method of claim 33, wherein the tertiary optic configuration comprises an inclined cover which is substantially hemispherical.

42. The method of claim 41, wherein the inclined cover further comprises at least one of an apex or a discontinuity.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] A complete understanding of the present invention may be obtained by reference to the accompanying drawings, when considered in conjunction with the subsequent, detailed description, in which:

[0030] FIG. 1 is a perspective view of one embodiment of a light fixture of the present invention;

[0031] FIG. 2 is a bottom view of the present invention;

[0032] FIG. 3 is a side view of the present invention;

[0033] FIG. 4 is a cross-sectional view highlighting airflow patterns generated by the light fixture;

[0034] FIG. 5 is a close-up view of the light fixture of FIG. 4;

[0035] FIG. 6 is a schematic view showing exemplary temperature gradients along a fin;

[0036] FIG. 7 is a top view of the present invention;

[0037] FIG. 8 is a schematic representation of a situation wherein a user may experience a high glare from a lighting fixture.

[0038] FIG. 9 is a cross-sectional view of a tertiary optic having a low profile.

[0039] FIG. 10 is a cross-sectional view of a tertiary optic having a higher profile.

[0040] FIG. 11 is a cross-sectional view of a tertiary optic further comprising an apex design element.

[0041] FIG. 12 is a cross-sectional view of a tertiary optic having a discontinuity in the curvature of the optic.

[0042] FIG. 13 is a polar distribution graph type V of a wide square lens configuration.

[0043] FIG. 14 is an ISO Ft-candle chart measured at 9′ mounting height of a wide square lens configuration.

[0044] FIG. 15 is a polar distribution graph type V of a narrow round lens configuration.

[0045] FIG. 16 is an ISO Ft-candle chart measured at 9′ mounting height of a narrow round lens configuration

DETAILED DESCRIPTION

[0046] Referring to FIGS. 1-3, there is provided a light fixture (10) generally 14 to 20 inched in diameter, and in this case a 17 inch diameter fixture was chosen. The light fixture (10) comprises at least one light source, which in this case is generally denoted as light emitting diodes LEDs (14). In this case an array of 48 LEDs (44) was chosen. For simplicity only a few exemplary samples are pointed out. The LEDs (14) are arranged in an array (12). A mounting base (22) providing mounting structures (not shown) and power source interface and control electronics (also not shown) are provided to facilitate providing lighting from the fixture.

[0047] Additionally, two of the features, as seen from a ground perspective view, are provided in an aesthetically pleasing way. They are an array covering (16) and a skirt (18), both providing additional functionality as will be explained hereafter. The array covering (16) is generally translucent and is can also be modified to provide functionality as a focusing lens or a diffusing lens in order to better focus or distribute light from the LED array (12) and into the intended space. The covering (16) can be seen as generally inclined from a minimum point in the center of the array (12) and upward toward the skirt (18). The preferred form for the covering (16) in the example is substantially hemispherical, or saucer shaped, as this will provide laminar flow is such a way as to maximize inlet velocities and ultimately cooling capability. It is anticipated that those skilled in the art can appreciate that there are many suitable implementations of an inclined covering (12) for channeling an updraft of air. The skirt (18) forms a; rim, periphery, cincture, encasement, edging, or environs for the area encircled. In another aspect it also forms a part of the heat transfer surface area.

[0048] As seen in FIG. 4, heat from the LEDs (14) is conducted outward heating the thermal backplane (26), the fins (20) and the skirt (18) by means of conductive heat transfer. This heat combined with heat generated in the mounting base (22) causes an updraft of air (24) from below which is directed by the covering (16) toward a manifold structure (30) which generally comprises the skirt (18) and the fins (20). It is anticipated that the heated air will comprise a laminar flow diverging or deflecting from the center of the array covering (16) and concentrating near the inlet (24′) of the manifold as seen in FIG. 5. The manifold (30) can be defined as comprising; a bottom (17), wall (18), fins (20) and thermal backplane (26) which form a series of chambers (21), roughly 32 to 40 chambers being approximately ¾ inch by 2 inches in cross section in this example. Further, the bottom (17) and wall of the skirt (18) are constricted by the edge of the thermal backplane (25) which then opens up causing a venturi effect which lowers pressure and increases flow through the chambers (21) of the manifold (30). The opening, which for present purposes is formed between the skirt (18) and the mounting base (22) and shown in FIG. 5 is an approximate seven fold expansion as seen by the cross section of a fin (20). It is also anticipated that the skirt (18) and the fins (20) can be formed as one structure of cast metal, such as cast aluminum.

[0049] Heat which is carried by the backplane (26) can be conducted either directly or through an interface (25) to the fins (20) by means of conductive heat transfer which is an efficient form of heat transfer. The venturi effect alters the boundary conditions of the convective heat transfer across the skirt (18) and the fins (20) moving the heat transfer mechanism from free convection to induced convection. It is anticipated that the heated air will generally transition to turbulent flow within the chambers (21).

[0050] FIG. 6 illustrates an effective temperature gradient for one aspect of the invention. In FIG. 6, ‘n’ denotes a starting temperature in degrees Celsius at the proximal edge of the fin (20) and closest to the mounting base (22). Starting at “n”; and moving left, the zones; ‘n-1’; ‘n-2’, ‘n-3’, ‘n-4’, ‘n-5’, and ‘n-6.5’ denote lower temperatures in degrees Celsius as distributed along the fin as it moved distally or radially outward. As is known by those skilled in the art of heat transfer, such temperature gradients provide a sufficient driving force for more heat to be conducted across the interface (25) thus facilitating further heat transfer. It can also be appreciated by those skilled in the art that providing a low thermally resistive path between the thermal backplane (26) and the fins (20), and if an interface (25) is used, thermal aids such as adding thermal grease or increasing the area of connection, and the like, can be added to increase the heat transfer.

[0051] FIGS. 8 and 9 illustrate conditions and principles of use where a tertiary optic is particularly effective. In individual approaches a door in a parking garage. Light fixtures (10) are located in the general parking area and in a relatively low line of sight of the viewer. An array of LED light sources (14), each generate some quantum of light. Each LED emanating rays (80) which can be seen as forming a main beam at a high incidence angle from the substrate. The incidence angle can be referenced with the backplane (26) and denoted as θ.sub.1 between the nadir, which is substantially normal to the substrate in this instance, and the main beam of light. Ideally θ.sub.1 is greater than 60° from the nadir to the rays (80) but can range between 50° and 80°. Each ray (80) creating an offensive glare until it reaches the lens covering (16) which forms the tertiary optic diffusing or scattering each ray (80) into a plurality of rays (82) creating a pleasing low glare illumination.

[0052] Each of the rays (80) strike the surface of the lens (16) forming an angle of refraction θ.sub.2 between the ray (80) and a tangent to the particular point of incidence. Ideally the lens should be formed to incorporate a steep angle of refraction θ.sub.2 preferably approaching 90°. The exiting rays (82) being highly scattered and diffused by texturing applied to the lens.

[0053] The lens should be of UV stabilized high impact resistant acrylic, polycarbonate, or like material. Dispersion through the lens can be created texturing the lens. Texturing can be formed by a mild acid etch to the mold which textures the surface of the lens through the injection molding process. Design elements should include a distance of at least two inches between the LED light source (14) and the lens (16) in order to prevent pixilation, or discernment of individual point light sources of the individual LEDs (14). Another means of creating dispersion would be to form a lens having a multiplicity of nano elements in the acrylic or polycarbonate material creating boundary layers within the injection molded lens.

[0054] Design parameters that may be used in accordance with this methodology can include changing the depth of the lens (16A) as shown in FIG. 10. One skilled in the art would understand the trade-offs between depth of lens (16A) and the optimization of θ.sub.2 and height requirements for low ceiling structures, also, there will be effects of the updraft for thermal reasons. These parameters can be adapted with little or no experimentation by those skilled in the art to meet the individual design requirements.

[0055] FIGS. 11 AND 12 illustrate various other lens designs with can accommodate the present objectives. For example; FIG. 11 depicts an apex (84) or pointed section in the formation of the lens (16B). FIG. 12 depicts a break or discontinuity (86) in the lens (16C). Each of which will bring about a different distribution of rays (82) having different illumination and visual effects. Care should be taken in design of the discontinuity (86) so as not to disrupt the laminar flow characteristics desired for the updraft of air (24).

[0056] FIG. 13 depicts a type V wide square distribution plotted on polar coordinates for one embodiment light fixture (not shown). It is desirable to have a wide angle batwing distribution as measured via a horizontal cone (70) through vertical angle zero. A vertical plane through horizontal angles (0-180) for the embodiment is depicted in (72). FIG. 14 depicts an ISO compliant ft-candle chart generated by the present embodiment for a light fixture mounted at nine feet height above a flooring surface. Note the shape and scale depicting the light distribution across a zone of space.

[0057] FIG. 15 depicts a type V narrow round distribution plotted on polar coordinates for an alternate embodiment light fixture (not shown). The corresponding horizontal cone (76) is depicted. A vertical plane through angles (0-180) for the embodiment is depicted in (74). FIG. 16 depicts an ISO compliant ft-candle chart generated by the alternate embodiment for a light fixture mounted at nine feet height above a flooring surface. Note the shape and scale depicting the light distribution across a zone of space.

CONCLUSION, RAMIFICATIONS, AND SCOPE

[0058] Although the present invention has been described in detail, those skilled in the art will understand that various changes, substitutions, and alterations herein may be made without departing from the spirit and scope of the invention in its broadest form. The invention is not considered limited to the example chosen for purposes of disclosure, and covers all changes and modifications which do not constitute departures from the true spirit and scope of this invention.

[0059] For example, although the foregoing refers to a circular perimeter lighting fixture, those skilled in the art can appreciate that polygonal, such as square, hexagon, or octagon can be utilized. In another example, the generally hemispherical array covering can also be replaced by a suitable covering having and inclined slope directed toward the perimeter of the fixture. Further, details may vary from structure to structure in terms of dimensions, scaling, and sizing of the array and fixture the exact position and type of optics deployed, depending on the physical arrangement of the structural members.

[0060] Having thus described the invention, what is desired to be protected by Letters Patent is presented in the subsequent appended claims.