Patent Application
20110242822
The present invention relates generally to optical systems for luminaires. More specifically, the present invention relates to an optical system for light emitting diode (“LED”) based lighting systems having two or more reflectors.
A luminaire is a system for producing, controlling, and/or distributing light for illumination. For example, a luminaire can include a system that outputs or distributes light into an environment, thereby allowing certain items in that environment to be visible. Luminaires are often referred to as “light fixtures”. Conventional luminaires typically use conventional optical systems, including, a total internal reflection (“TIR”) lens, a hybrid optical system which includes a refractor and a reflector combination system, and/or a single reflector, for obtaining a desired light distribution. However, at least two issues arise when using conventional optical systems. One is that the lens turns a yellowish color, thereby significantly reducing the efficiency of the light output. The yellowing issue is caused, in large part, because the lens is fabricated from a plastic material, such as a polymethylmethacrylate (“PMMA”) or acrylic, or a polycarbonate material, and turns slightly yellow in color when exposed to high temperatures and/or ultraviolet light over time. Yellowing of the lens significantly reduces the efficiency of the light output therethrough because less light is transmitted to an area that is intended to be illuminated.
The useful life of TIR and hybrid lenses can be significantly less than the life of the LED. Selecting a TIR lens material that equals or exceeds the life of the LED can be cost prohibiting for the light fixture market.
In addition, when using a single reflector to obtain the desired light distribution, a halo effect is often created on the area that is to be illuminated.
One solution to correct the halo effect is to cover the second opening 175 with a diffuse lens (not shown). However, adding a diffuse lens increases the cost of the optical system and also reduces light output and light efficiency. Another solution to correct the halo effect is to increase the height of the reflector 170. However, doing so makes the single reflector 170 very tall, which would make using the single reflector 170 within existing light fixtures mechanically unfeasible. Additionally, increasing the height of the reflector 170 increases the amount of material costs.
One exemplary embodiment of the invention includes an optical system. The optical system can include an outer reflector and at least one inner reflector. At least one inner reflector can be positioned within a cavity formed in the outer reflector such that the outer reflector surrounds at least a portion of the inner reflector. The outer reflector can include an outer reflector proximal end, an outer reflector distal end, and an outer reflector internal surface. The outer reflector internal surface can extend from the outer reflector proximal end to the outer reflector distal end. Each inner reflector can include an inner reflector proximal end, an inner reflector distal end, and an inner reflector internal surface. The inner reflector internal surface can extend from the inner reflector proximal end to the inner reflector distal end.
Another exemplary embodiment of the invention includes an optical system. The optical system can include an outer reflector assembly plate and at least one inner reflector assembly coupled to the outer reflector assembly plate. The outer reflector assembly plate can include one or more outer reflectors arranged in an array. Each outer reflector can include an outer reflector proximal end, an outer reflector distal end, and an outer reflector internal surface. The outer reflector internal surface can extend from the outer reflector proximal end to the outer reflector distal end. Each inner reflector assembly can include one or more inner reflectors. Each inner reflector can include an inner reflector proximal end, an inner reflector distal end, and an inner reflector internal surface. The inner reflector internal surface can extend from the inner reflector proximal end to the inner reflector distal end. At least one inner reflector can be positioned within a corresponding outer reflector.
Another exemplary embodiment of the invention includes a luminaire. The luminaire can include a plurality of light emitting diodes (“LEDs”), an outer reflector, and at least one inner reflector. The outer reflector can include an outer reflector proximal end, an outer reflector distal end, and an outer reflector internal surface. The outer reflector internal surface can extend from the outer reflector proximal end to the outer reflector distal end. Each inner reflector can include an inner reflector proximal end, an inner reflector distal end, and an inner reflector internal surface. The inner reflector internal surface can extend from the inner reflector proximal end to the inner reflector distal end. At least one inner reflector can be positioned within the outer reflector such that the outer reflector surrounds the inner reflector. The LEDs can be positioned adjacent the outer reflector proximal end such that the outer reflector proximal end surrounds the LED.
Another exemplary embodiment of the invention includes a luminaire. The luminaire can include a substrate, a platform, and one or more inner reflector assemblies. The substrate can include an array of LEDs. The platform can include an array of outer reflectors disposed within the platform and a cavity formed within the platform between each pair of outer reflectors. Each outer reflector can include a first opening and a second opening. The first opening can be located at a proximal end of the outer reflector, while the second opening can be located at a distal end of the outer reflector. Each inner reflector assembly can include a base, one or more inner reflectors, and one or more arms extending from the base to the inner reflector. Each inner reflector can include a first opening located at a proximal end of the inner reflector and a second opening located at a distal end of the inner reflector. The base can be coupled to the cavity to position the inner reflector within a respective outer reflector. The proximal end of each outer reflector can rest upon the substrate and receive one or more LEDs within the first opening of the outer reflector.
The foregoing and other features and aspects of the invention may be best understood with reference to the following description of certain exemplary embodiments, when read in conjunction with the accompanying drawings, wherein:
The drawings illustrate only exemplary embodiments of the invention and are therefore not to be considered limiting of its scope, as the invention may admit to other equally effective embodiments.
The invention is better understood by reading the following description of non-limiting, exemplary embodiments with reference to the attached drawings, wherein like parts of each of the figures are identified by like reference characters throughout, and which are briefly described below. Although the description of exemplary embodiments is provided below in conjunction with an LED light source, alternate embodiments are applicable to other types of light sources including, but not limited to, high intensity discharge (“HID”) lamps, fluorescent lamps, compact fluorescent lamps (“CFLs”), and incandescent lamps. Additionally, the exemplary embodiments described herein are capable of being modified to operate in several different lighting applications including, but not limited to, sign light applications, flood light applications, and internal lighting applications.
According to one exemplary embodiment, the outer reflector assembly plate 210 includes ten outer reflectors 220 arranged in a two by five rectangular array. However, according to alternate exemplary embodiments, the number of outer reflectors is greater or fewer and arranged in any array shape including, but not limited to, circular, square, triangular, or any other geometric or non-geometric shape without departing from the scope and spirit of the exemplary embodiment. In one exemplary embodiment, each outer reflector 220 is integrally formed into the outer reflector assembly plate 210 as a single piece. However, in alternate exemplary embodiments, at least one outer reflector 220 is separately formed from the outer reflector assembly plate 210 and thereafter coupled to the outer reflector assembly plate 210 using a fastening means (not shown) known to people having ordinary skill in the art including, but not limited to, welding, soldering, snap-fitting, and screwing it on.
Each outer reflector 220 includes an outer reflector proximal end 222, an outer reflector distal end 224, and an outer reflector internal surface 226 extending from the outer reflector proximal end 222 to the outer reflector distal end 224. The outer reflector proximal end 222 is positioned distally from the first surface 212, while the outer reflector distal end 222 is positioned at the first surface 212. The outer reflector proximal end 222 forms an outer reflector proximal opening 223, while the outer reflector distal end 224 forms an outer reflector distal opening 225. In one exemplary embodiment, each of the outer reflector proximal opening 223 and the outer reflector distal opening 225 are circular. Each outer reflector 220 also includes an outer reflector axial axis 229, which includes the centerpoint of the outer reflector proximal opening 223 and the centerpoint of the outer reflector distal opening 225. According to one exemplary embodiment, the diameter of the outer reflector proximal opening 223 is less than the diameter of the outer reflector distal opening 225. However, in alternative embodiments the diameter of the outer reflector proximal opening 223 is equal to or greater than the diameter of the outer reflector distal opening 225. In the exemplary embodiment of
At least a portion of the outer reflector assembly plate 210 and the outer reflectors 220 are fabricated from plastic material including, but not limited to, PMMA or polycarbonate. At least a portion of the plastic material, including the outer reflector internal surface 226, is coated with a metallic material, such as aluminum or stainless steel, according to processes known to people having ordinary skill in the art, including, but not limited to, vacuum metalizing. Other materials can be used in lieu of or in addition to the plastic material. These materials include, but are not limited to, spun aluminum, turned aluminum, or any other reflective material known to people having ordinary skill in the art.
The outer reflector assembly plate 210 includes one or more attachment openings 230. Fasteners, such as a screws, are positioned through the openings 230 to couple the outer reflector assembly plate 210 to a light assembly (not shown) that includes one or more light sources (not shown), such as an LED. In one exemplary embodiment, which is discussed below in further detail in conjunction with
The outer reflector assembly plate 210 also includes one or more recesses 590 positioned adjacent to at least one outer reflector 220 and formed on the first surface 212 of the outer reflector assembly plate 210. The exemplary recess 590 is square-shaped, but is capable of being any geometric or non-geometric shape without departing from the scope and spirit of the exemplary embodiment. The recess 590 receives a portion of the inner reflector assembly 250, which is discussed in further detail below.
The exemplary base 260 is square-shaped and is slidably insertable into the recess 590 (
Each inner reflector 270A and 270B includes an inner reflector proximal end 272, an inner reflector distal end 274, an inner reflector internal surface 276 extending from the inner reflector proximal end 272 to the inner reflector distal end 274, and an inner reflector external surface 610 extending from the inner reflector proximal end 272 to the inner reflector distal end 274. The inner reflector proximal end 272 forms an inner reflector proximal opening 273, while the inner reflector distal end 274 forms an inner reflector distal opening 275. Each inner reflector 270A and 270B also includes an inner reflector axial axis 279, which includes the centerpoint of the inner reflector proximal opening 273 and the centerpoint of the inner reflector distal opening 275. In one exemplary embodiment, both the proximal opening 273 and the distal opening 275 are circular; however, other opening shapes are within the scope and spirit of the exemplary embodiment.
According to one exemplary embodiment, the diameter of the inner reflector proximal opening 273 is less than the diameter of the inner reflector distal opening 275. In alternative embodiments, the diameter of the inner reflector proximal opening 273 is equal to or greater than the diameter of the inner reflector distal opening 275. The exemplary inner reflector internal surface 276 is smooth. However, in alternative embodiments, the inner reflector internal surface 276 is faceted, dimpled, or uneven in other exemplary embodiments. Additionally, the exemplary inner reflector external surface 610 is smooth. However, in alternative embodiments, the inner reflector external surface 610 is faceted, dimpled, or uneven in other exemplary embodiments. According to the exemplary embodiment, the shape of the inner reflector 270A and 270B is conical; however other geometric and non-geometric shapes including, but not limited to, parabolic, are within the scope of this disclosure. Although some exemplary embodiments have an inner reflector assembly 250 that has two inner reflectors 270A and 270B coupled together, other exemplary embodiments have an inner reflector assembly that has greater or fewer inner reflectors.
Although bars 262 and 264 are used for coupling the inner reflectors 270A and 270B to the base 260 and for positioning the inner reflectors 270A and 270B within the corresponding outer reflector 220, other devices are capable of positioning the inner reflectors 270A and 270B within the corresponding outer reflector 220. For example, each inner reflector 270A and 270B is capable of being positioned within the corresponding outer reflector 220 using a similar bar that extends from the outer reflector internal surface 226 to the inner reflector 270A and 270B.
In the exemplary embodiment, the light source 410 is positioned substantially on both the inner reflector axial axis 279 and the outer reflector axial axis 229. The light source 410 is position adjacent the outer reflector proximal end 222 such that the outer reflector proximal end 222 is disposed around the light source 410. The light source 410, which in this exemplary embodiment is an LED, is mounted to and electrically coupled to a substrate 400. The substrate 400 is coupled to and in thermal communication with the assembly. In alternative exemplary embodiments where other light sources, such as HID lights, fluorescent lights, CFLs, and incandescent lamps, are used, the substrate 400 is removed and the light source 400 is directly coupled to the assembly by way of a complementary lamp socket. According to this exemplary embodiment, the outer reflector proximal ends 222 are oriented on top of the side of the substrate 400 having the LEDs 410. Further, the outer reflector assembly plate 210 is positioned such that a portion of each respective LED 410 is located substantially in and extends, at least partially, through the center of the outer reflector proximal opening 223.
According to this exemplary embodiment, the substrate 400 includes one or more sheets of ceramic, metal, laminate, circuit board, mylar, or another material. Each LED 410 includes a chip of semi-conductive material that is treated to create a positive-negative (“p-n”) junction. When the LED 410 or LED package is electrically coupled to a power source, such as an LED driver (not shown), current flows from the positive side to the negative side of each junction, causing charge carriers to release energy in the form of incoherent light.
The wavelength or color of the emitted light depends on the materials used to make the LED 400 or LED package. For example, a blue or ultraviolet LED typically includes gallium nitride (“GaN”) or indium gallium nitride (“InGaN”), a red LED typically includes aluminum gallium arsenide (“AlGaAs”), and a green LED typically includes aluminum gallium phosphide (“AlGaP”). Each of the LEDs 400 in the LED package can produce the same or a distinct color of light. For example, in certain exemplary embodiments, the LED package include one or more white LED's and one or more non-white LEDs, such as red, yellow, amber, or blue LEDs, for adjusting the color temperature output of the light emitted from the luminaire. A yellow or multi-chromatic phosphor may coat or otherwise be used in a blue or ultraviolet LED to create blue and red-shifted light that essentially matches blackbody radiation. The emitted light approximates or emulates “white,” incandescent light to a human observer. In certain exemplary embodiments, the emitted light includes substantially white light that seems slightly blue, green, red, yellow, orange, or some other color or tint. In certain exemplary embodiments, the light emitted from the LEDs has a color temperature between 2500 and 5000 degrees Kelvin.
In certain exemplary embodiments, an optically transmissive or clear material (not shown) encapsulates at least a portion of each LED 410 or LED package. This encapsulating material provides environmental protection while transmitting light from the LEDs 410. In certain exemplary embodiments, the encapsulating material includes a conformal coating, a silicone gel, a cured/curable polymer, an adhesive, or some other material known to a person of ordinary skill in the art having the benefit of the present disclosure. In certain exemplary embodiments, phosphors are coated onto or dispersed in the encapsulating material for creating white light. In certain exemplary embodiments, the white light has a color temperature between 2500 and 5000 degrees Kelvin.
In certain exemplary embodiments, the LED 410 is an LED package that includes one or more arrays of LEDs 410 that are collectively configured to produce a lumen output from 1 lumen to 5000 lumens. The LEDs 410 or the LED packages are attached to the substrate 400 by one or more solder joints, plugs, epoxy or bonding lines, and/or other means for mounting an electrical/optical device on a surface. The substrate 400 is electrically connected to support circuitry (not shown) and/or the LED driver for supplying electrical power and control to the LEDs 410 or LED packages. For example, one or more wires (not shown) couple opposite ends of the substrate 400 to the LED driver, thereby completing a circuit between the LED driver, substrate 400, and LEDs 410. In certain exemplary embodiments, the LED driver is configured to separately control one or more portions of the LEDs 410 in the array to adjust light color or intensity.
The exemplary inner reflector proximal end 272 is positioned closer to the outer reflector proximal end 222, while the exemplary inner reflector distal end 274 is positioned closer to the outer reflector distal end 224. In one exemplary embodiment, the inner reflector distal end 274 and the outer reflector distal end 224 both lie in the same plane. Furthermore, in this exemplary embodiment, the inner reflector proximal end 272 and the outer reflector proximal end 222 lie in different planes. However, planar alignment for the distal ends 224, 274 are configurable in such a way that the distal ends 224, 274 are not aligned on the same plane. According to one exemplary embodiment, the inner reflector distal opening 275 has diameter 276 that is equal to the diameter 277 of the outer reflector proximal opening 223. Alternatively, the diameters 276, 277 are different.
The light source 410 emits beams of light 430 and 432 through the outer reflector distal opening 225 which proceed to a desired surface to be illuminated (not shown). The beams of light 430 and 432 include narrow angle beams of light 432 which pass through the interior of the inner reflector 270A and wide angle beams of light 430 which pass between the inner reflector exterior surface 610 and the outer reflector interior surface 226. The angles for the narrow beams of light 432 and the wide angle beams of light 430 are variable and dependent upon the dimensions of the outer reflector 220 and the inner reflector 270A and also on the positioning of the inner reflector 270A within the outer reflector 220. The positioning and shape of the inner reflector 270A within the outer reflector 220 prevents any significant amount of wide angle beams of light 430 to exit the outer reflector distal opening 225 without being reflected off the outer reflector internal surface 226. Additionally, according to some exemplary embodiments, the positioning and shape of the inner reflector 270A prevents any significant amounts of wide angle beams of light 430 to exit the outer reflector distal opening 225 and proceed to an area that surrounds the hot spot 102 (
As previously mentioned, a halo effect is formed when a light source creates a hot spot on the illumination area with a surrounding band at a lower lumen level than that of the lumen level of the hot spot. According to embodiments of this invention, the halo effect is eliminated or minimized because the inner reflector 270A prevents any wide angle beams of light 430 to exit the outer reflector distal opening 225 without being reflected off the outer reflector internal surface 226 and also prevents any significant amounts of wide angle beams of light 430 to exit the outer reflector distal opening 225 and proceed to an illuminated area that surrounds the hot spot. Thus, the surrounding band having a lower lumen level is not formed. The light emitted from the light source 410 is more concentrated within a smaller illumination area. Exemplary embodiments eliminate this halo effect while minimizing the height of the outer reflector 220.
Although some exemplary embodiments have one inner reflector 270A positioned within a corresponding outer reflector 220, some exemplary embodiments have more than one inner reflector 270A positioned within a corresponding outer reflector 220. For example, two or more inner reflectors 270A are positionable within the outer reflector, wherein the inner reflectors are spaced apart horizontally from one another, vertically from one another, or a combination of horizontally and vertically from one another.
Although each exemplary embodiment has been described in detail, it is to be construed that any features and modifications that are applicable to one embodiment are also applicable to the other embodiments. Although the invention has been described with reference to specific embodiments, these descriptions are not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments of the invention will become apparent to persons of ordinary skill in the art upon reference to the description of the exemplary embodiments. It should be appreciated by those of ordinary skill in the art that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures or methods for carrying out the same purposes of the invention. It should also be realized by those of ordinary skill in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. It is therefore, contemplated that the claims will cover any such modifications or embodiments that fall within the scope of the invention.
