Patent Application
20140160740
The present disclosure is generally directed toward light emitting devices.
Light Emitting Diodes (LEDs) have many advantages over conventional light sources, such as incandescent, halogen and fluorescent lamps. These advantages include longer operating life, lower power consumption, and smaller size. Consequently, conventional light sources are increasingly being replaced with LEDs in traditional lighting applications. As an example, LEDs are currently being used in flashlights, camera flashes, traffic signal lights, automotive taillights and display devices. LEDs have also gained favor in residential, industrial, and retail lighting applications.
The replacement of fluorescent tubes with LED tubes is becoming much more commonplace. In particular, the LED-based solutions serve as a quick replacement to fluorescent tubes for energy conservation without the need of changing fixtures or troffers. Most LED tubes are cylindrical in shape and have bi-pin end caps at both ends just like fluorescent tubes.
The efficiency of a conventional troffer is quantified by its light output ratio (LOR). LOR is the ratio of luminous flux emitted by the troffer to the luminous flux emitted by the tubes inside. In other words, LOR gives the optical efficiency of the troffer. LOR for a normal troffer with fluorescent tubes is generally about 70%. This means 30% of the light emitted by the fluorescent tubes inside are lost in the troffer due to absorption losses at the reflector, leakage through gaps, absorption by the fluorescent tubes themselves, etc. The light loss is high because fluorescent tubes produce a significant amount of up-light. When LED tubes are mounted in a conventional troffer, LOR can be improved to about 85-90% due to smaller amount of up-light produced by the LED tubes. However, there are still 10-15% of light losses in the troffer if a traditional LED tube is used to replace the fluorescent light tube.
It is, therefore, one aspect of the present disclosure to provide an illumination device that overcomes the above-noted shortcomings. In particular, embodiments of the present disclosure introduce an illumination device that can achieve approximately <5% of light losses when utilized in a traditional troffer. Specifically, the illumination device is configured to focus its light downwards and produce as little up-light as possible, thereby minimizing losses associated with reflection and absorption in the troffer.
Another aspect of the present disclosure is to provide an illumination device that is capable of producing elongated light with a controllable viewing angle, thereby enabling the illumination of a large selected area.
Another aspect of the present disclosure is to provide an illumination device and system, which can reduce energy consumption, even when compared with current LED-based solutions. In particular, with better LOR, less light is required of the illumination device to produce the same amount of luminance and, thus, equivalent light can be produced with less energy.
For elongated narrow angle illumination, embodiments of the present disclosure can produce illumination results with higher uniformity over conventional narrow angle spot lights and with higher efficiency over fluorescent tubes and conventional LED tubes. Light with different beam angles can be made according to the desired illumination size or area.
In accordance with at least one embodiment, an illumination device is disclosed that includes a heat sink, a transparent or translucent plastic cover and 2 bi-pin end caps which can be fitted into existing fluorescent light fixtures. In some embodiments, multiple LED components are populated on one or more substrates such as Printed Circuit Boards (PCBs), which, in turn, can be mounted on the heat sink. In some embodiments, the heat sink includes two or more reflective surfaces and the two or more reflective surfaces can be configured to partially surround both sides of the substrate(s). It is contemplated that these reflective surfaces may form an angle of <180°, and can act as a reflector to focus light that is emitted by the LED components. The reflective surface(s) may include high reflectivity films to improve the optical efficiency of the overall system. In some embodiments, the cavity or channel formed by the reflective surface can be covered by a cover. In some embodiments, the height difference of the bottom surface of the plastic cover is approximately <5 mm to minimize the production of up-light.
The present disclosure will be further understood from the drawings and the following detailed description. Although this description sets forth specific details, it is understood that certain embodiments of the invention may be practiced without these specific details. It is also understood that in some instances, well-known circuits, components and techniques have not been shown in detail in order to avoid obscuring the understanding of the invention.
The present disclosure is described in conjunction with the appended figures:
The ensuing description provides embodiments only, and is not intended to limit the scope, applicability, or configuration of the claims. Rather, the ensuing description will provide those skilled in the art with an enabling description for implementing the described embodiments. It is being understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the appended claims.
With reference now to
The illumination device 104 may be configured to emit light in a predetermined illumination profile 124 so as to illuminate one or more objects 116 on a wall 120, for example. Of course, the illumination device 104 may also be configured to emit its illumination profile 124 onto or toward the floor 128 and/or wall 120, depending upon the lighting effects desired for the illuminated area 100.
In a specific but non-limiting embodiment, the illuminated object 116 may correspond to a painting, work of art, shelving, or any other object that is desired to be illuminated. Advantageously, the illumination device 104 is capable of producing an illumination profile 124 that is relatively uniform across a substantial (e.g., uniform across more than the length of the illumination device 104 which can be 1-2 m in length. This illumination profile 124 is also directed/focused at the object 116, thereby decreasing the amount of energy required to adequately illuminate the object 116.
With reference now to
It should be appreciated that the illumination device 104 may comprise more or less pins than depicted. For instance, each end 304, 308 may only have one pin. As another example, each end 304, 308 may have more than two pins. Further still, it is not a requirement that every pin be used to carry electrical current. Instead, one or more pins may be used solely for mechanical support.
With reference now to
In some embodiments, the lighting fixture 404 may correspond to a troffer or the like and may include one or more reflectors 408. The reflectors 408 of the fixture 404 may originally have been provided to reflect up-light produced by a fluorescent lighting tube, for example. As can be seen in
With reference now to
In some embodiments, the illumination device 104 comprises a heat sink 504 having a top portion 508 and bottom portion 512. The heat sink 504 may be constructed of any material or combination of materials that is capable of transferring heat in an efficient manner. More specifically, the heat sink 504 may comprise a metal or aluminum alloy that is configured to disperse heat toward the outer curved surface of the heat sink 504. Although not depicted, the heat sink top portion 508 may comprise one or more heat dissipating elements (e.g., fins, ribs, grooves, etc.) to help increase the surface area of the heat sink top portion 508, thereby increasing the efficiency with which the heat sink 504 transfers heat to its environment.
In accordance with a generally tube-like shape, the heat sink top portion 508 is rounded, much like a fluorescent lighting tube. The heat sink bottom portion 512, however, may be flanged or transition from the curvature of the heat sink top portion 508 into a more straight line. In some embodiments, the heat sink 504 also comprises a depression or channel 516 that is open at the heat sink bottom portion 512. In some embodiments, the channel 516 traverses substantially the entirety of the body portion 312 of the illumination device 104.
The channel 516 may extend into the heat sink 504 such that its upper surface is closer to the heat sink top portion 508 rather than the heat sink bottom portion 512. In some embodiments, the top of the channel 516 may comprise a generally planar surface that is configured to receive and have mounted thereto a substrate 528. The substrate 528 may be configured to support or have mounted thereto one or more light sources 532. Like the channel 516, the top surface of the channel 516 may extend substantially across the entire body portion 312 and light sources 532 may be mounted along the same length.
In a specific but non-limiting embodiment, the top surface of the channel 516 may be substantially planar and the substrate 528 may correspond to a Printed Circuit Board (PCB) that is mounted, soldered, or affixed to the top surface of the channel 516. The substrate 528 may correspond to a rigid or flexible PCB. One function of the substrate 528 may be to provide a surface onto which the light source(s) 532 can be mounted. Another function of the substrate 528 may be to carry electrical current to/from the light source(s) 532, thereby enabling their functionality. More specifically, one or more leads on the substrate 528 may be connected to an external source of current or power via one or more of the pins 316, 320. Even more specifically, one or more of the pins 316, 320 may be electrically connected to in-wall wiring as well as one or more electrical traces in the substrate 528. One or more power transformers or power conditions may also be mounted to the substrate 528 to condition the power received at the pins 316, 320 for providing to the light source(s) 532. The traces of the substrate 528 may be configured to carry electrical current to the light source(s) 532, thereby enabling the light source(s) 532 to produce emitted light 412.
Any type of known light source may be used for the light sources 532. As some non-limiting examples, the light source(s) 532 may correspond to an LED, an array of LEDs, a laser diode, or the like. In some embodiments, a plurality of LEDs are mounted onto the substrate 528 and are configured to emit light when a voltage difference is applied across the anode and cathode of the LEDs. In some embodiments, the light source(s) 532 may comprise a thru-hole mount LED and/or surface mount LED. The light source(s) 532 may be mounted onto or thru the substrate 528 in a known fashion and then the substrate 528 may be mounted to the top surface of the channel 516 such that the light emitting surfaces of the light sources 532 are pointing toward the opening of the channel 516. Another type of light sources 532 that may be employed in accordance with embodiments of the present disclosure is an Organic LED (OLED) sheet or film. The OLED sheet or film may be mounted or adhered to the substrate 528. Alternatively or additionally, the OLED sheet or film may be mounted across the entirety of the top surface of the channel 516 as well as along one or both of the adjacent walls that establish the channel 516. The OLED sheet may have its electrodes connected to different leads that are either established on the substrate 528 or at some other portion of the illumination device 104.
Although not depicted, other electrical and electro-mechanical devices may also be mounted on the substrate 528. For instance, resistors, capacitors, inductors, transistors, sensors, motor components, etc. may be mounted on the substrate 528.
In some embodiments, the light source(s) 532 are configured to emit light 412 of a predetermined wavelength or color. More specifically, the light source(s) 532 may be configured to produce and emit light 412 that is approximately blue or Ultraviolet (e.g., with a wavelength of greater than approximately 445 nm), Infrared (e.g., with a wavelength between 1 mm and 750 nm), or any wavelength therebetween.
In some embodiments, the light source(s) 532 are configured to inherently produce heat during operation. The material of the heat sink 504 may be selected to help dissipate heat produced by the light source(s) 532 away from the light source(s) 532. More specifically, as noted above, the heat sink 504 may be made of aluminum or a similar type of material.
The channel 516 may also have two or more reflective walls 520, 524 that establish the side boundaries of the channel 516. One or both of the reflective walls 520, 524 may be made of or have applied thereto a reflective material to help decrease losses of light that is reflected by the walls 520, 524. As a non-limiting example, one or both walls 520, 524 may have a reflective film applied thereto along the length of the channel 516. The reflective material may be applied to the walls 520, 524 via an adhesive or the like. Alternatively or additionally, the reflective material may be sputtered or applied to the walls 520, 524 via one or more of Chemical Vapor Deposition (CVD), Atomic Layer Deposition (ALD), or the like. Although not depicted, some or all of the substrate 528 may have a reflective material to further increase the reflectivity within the channel 516.
Although the walls 520, 524 are depicted as being substantially flat or planar, it should be appreciated that the walls 520, 524 and/or top surface of the channel 516 may be non-planar. As an example, the walls 520, 524 may be curved inwardly or outwardly (continuously or discretely) to further help shape light reflected within the channel 516. Additionally or alternatively, the relative angle between the first reflective wall 520 and second reflective wall 524 may be any angel between approximately 0 degrees and 180 degrees and the dimensions of the channel 516 may be adjusted to accommodate various type of desired lighting effects.
In some embodiments, the channel 516 may be partially or completely filled with air or an ambient gas. In some embodiments, the channel 516 may be partially or completely filled with a non-gas material. As some examples, the channel 516 may be filled with a transparent or translucent material such as epoxy, silicone, a hybrid of silicone and epoxy, phosphor, a hybrid of phosphor and silicone, an amorphous polyamide resin or fluorocarbon, glass, plastic, or combinations thereof.
When the channel 516 is not completely filled with a solid material, the opening of the channel 516 may interface with a cover 536 or similar type of element. The cover 536 may provide many advantageous functions. As one example, the cover 536 may protect the light source(s) 532 from dirt, debris, and other ambient hazards. As another example, the cover 536 may provide light-shaping/light-directing functions. More specifically, the illustrative cover 536 may comprise one or more Fresnel lens elements incorporated therein. Moreover, the illustrative cover 536 may comprise a bend or domed shape to further minimize the amount of up-light produced. Specifically, the cover 536 may comprise a profile whereby its bottom surface is curved or non-linear and a height difference is established between the middle of the cover 536 and the points where the cover 536 interface with the heat sink bottom portion 512. In some embodiments, this height difference may be less than or equal to 5.0 mm or more particularly less than or equal to 2.5 mm.
The cover 536 may be manufactured of a transparent or translucent material that may be rigid or flexible. In some embodiments, the cover 536 correspond to a transparent plastic material that is non-rigidly flexible (e.g., polyethylene, polypropylene, polystyrene, polyvinyl chloride, polytetrafluoroethylene (PTFE), etc.). The Fresnel lens elements of the cover 536 may further help direct light downward as well as soften the light before it exits the illumination device 104.
In the depicted embodiment, the cover 536 interfaces with the heat sink bottom portion 512 with a snap fit 540. It should be appreciated that other mechanical or non-mechanical mechanisms can be used to connect the cover 536 with the heat sink 504. For instance, adhesives, welding, glue, friction fit, snaps, rivets, buttons, or the like can be used to fasten or secure the cover 536 to the heat sink 504.
With reference now to
With reference now to
Specific details were given in the description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, circuits may be shown in block diagrams in order not to obscure the embodiments in unnecessary detail. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments.
While illustrative embodiments of the disclosure have been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed, and that the appended claims are intended to be construed to include such variations, except as limited by the prior art.
