Patent Application
20140146517
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.
LED development began with infrared and red devices made with gallium arsenide. Advances in materials science have enabled making devices with ever-shorter wavelengths, emitting light in a variety of colors.
There are two primary ways of producing white light-emitting diodes (WLEDs)—LEDs that generate high-intensity white light. One is to use individual LEDs that emit three primary colors (red, green, and blue) and then mix all the colors to form white light. The other is to use a phosphor material to convert monochromatic light from a blue or Ultraviolet LED to broad-spectrum white light, much in the same way a fluorescent light bulb works.
One disadvantage to utilizing phosphor in connection with LEDs is that the phosphor degrades due to the operating conditions imposed on the phosphor. Specifically, the LED die(s) are known to generate significant heat during operation. The heat generated by the LED die(s) creates a high temperature environment about the phosphor if the phosphor is in contact with or near the LED die(s), which causes the phosphor to degrade more rapidly than if it were exposed to lower operating temperatures.
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 having a core and a shaft with a gap that resides between the core and shaft. One or more light sources, such as LED dies, may be mounted on the core and configured to emit light away from the core toward the shaft. The shaft may be provided with one or more light-altering elements (e.g., filter, phosphor, lens, etc.) that alter the light emitted by the light sources in one way or another. In some embodiments, the shaft is equipped with one or more phosphor elements that convert the light emitted by the light source(s) mounted on the core into broad-spectrum white light.
In some embodiments, the shaft may be further configured to move or rotate relative to the core. More specifically, the shaft may be operably associated with a shaft motor and the shaft motor may cause the shaft to rotate relative to the core. Even more specifically, the shaft motor may be configured to rotate the shaft at a predetermined rotational speed to control the quality of light that ultimately leaves the illumination device. For example, the shaft motor may be configured to rotate the shaft at a relatively high speed to create a first illumination effect or a relatively low speed to create a second illumination effect. In some embodiments, the shaft motor may be attached to or have incorporated therein one or more light detectors that are configured to monitor the light emitted by the illumination device (e.g., ambient or environmental light conditions outside of the illumination device). Based on detected light conditions, the shaft motor may be configured to speed up or slow down the rotation of the shaft relative to the core.
In some embodiments, the illumination device described herein is capable of creating vivid color or white light depending upon the way in which the shaft is controlled. Different rotating speeds may be used to produce different colors or white light. In some embodiments, the light sources mounted on the core may correspond to blue or Ultraviolet LEDs that emit light toward the shaft. The emitted light can excite the phosphor elements to produce photoluminescence while the rotating shaft can mix or blend the excited photoluminescence.
Another advantage of the present disclosure is that the core can be configured to transfer and dissipate heat created by the light sources. The enhanced heat transfer properties offered by the core can help maintain the junction temperature of the light sources, thereby increasing their operational lifetime. Moreover, because the shaft and its phosphor element(s) are physically separated from the core and the light source(s), the deleterious effects of heat from the light sources on the phosphor can be minimized, thereby minimizing phosphor degradation.
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 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
In the embodiment depicted in
One possible function of the core 108 is to physically support and provide electrical current to one or more light sources 112. The one or more light source 112 may be configured to be mounted to the outer surface of the core 108. In some embodiments, the core 108 may comprise a PCB component and the light source(s) 112 may be configured for surface mounting to the PCB component of the core 108. In some embodiments, the light source(s) 112 may be configured for thru-hole mounting to the PCB component of the core 108. In some embodiments, some light source(s) 112 may correspond to surface mount device and other light source(s) 112 may correspond to thru-hole devices. In some embodiments, some light source(s) 112 may correspond to one or more Organic LED (OLED) sheets or films. The OLED sheet may be wrapped around the core 108 and have its electrodes connected to different leads.
Although not depicted, other electrical and electro-mechanical device may also be mounted on the outer surface of the core 108. For instance, resistors, capacitors, inductors, transistors, sensors, motor components, etc. may be mounted on the core 108.
In some embodiments, the light source 112 is configured to emit light 116 of a predetermined wavelength or color. More specifically, the light source(s) 112 may be configured to produce and emit light 116 that is approximately blue or Ultraviolet (e.g., with a wavelength of greater than approximately 445 nm). More specifically, the light source(s) 112 may correspond to one or more LED dies. The LED die(s) may be configured to emit substantially blue or Ultraviolet light 116 when current is passed therethrough (e.g., when the LED is activated with current flowing from the PCB of the core 108). Any type of known LED may be used for the light source(s) 112 and they light source(s) 112 may be mounted and electrically connected to the core 108 in any known fashion (e.g., via wires, bonding pads, surface contacts, etc.).
In some embodiments, the light source(s) 112 are configured to inherently produce heat during operation. The material of the core 108 may be selected to help dissipate heat produced by the light source(s) 112 away from the light source(s) 112. More specifically, as noted above, the core 108 may comprise a flexible PCB mounted on a heat sink. The heat sink may comprise any type of material that is known to be thermally conductive. In other words, the material of the core 108 may be used to carry heat away from the light source(s) to increase their life span.
In some embodiments, the length of the core 108 may be similar in dimension to traditional fluorescent light tubes (e.g., approximately 1-2 m in length). In particular, the core 108 may have coupling mechanisms at each of its ends that enable the illumination device 100 to replace a traditional fluorescent light. Examples of such coupling mechanisms are described, for instance, in U.S. Pat. No. 6,860,628 to Robertson et al., the entire contents of which are hereby incorporated herein by reference.
The shaft 104 of the illumination device 100 may provide several functions. In some embodiments, the shaft 104 may comprise one or more shaft sections 120 that are each configured to condition the light 116 emitted by the light source(s) 112. The shaft sections 120 may comprise similar or different light-conditioning properties. In some embodiments, a first shaft section 120 may provide a first light-conditioning property and a second shaft section 120 may comprise a second light-conditioning property that is different from the first section. More specifically, some of the shaft sections 120 may comprise one type of material while other shaft sections 120 may comprise a different type of material.
Although the shaft 104 of
In some embodiments, the shaft 104 comprises an inner shaft surface 132 and an outer shaft surface 128. One or more light-altering or conditioning materials may be contained between the inner shaft surface 132 and outer shaft surface 128. Furthermore each section 120 may be separated by its adjacent sections 120 by a section boundary 124. The section boundary 124 may correspond to an area or point where there is a transition from one material of one section 120 to another material of another section 120. Even more specifically, some sections 120 may be provided with a first type of phosphor material while other sections 120 may be provided with a second type of phosphor material. The different sections 120 may also comprise other types of non-phosphor materials that differ from one another. For instance, some of the sections 120 may comprise materials that filter or shape light in one way while other sections 120 may comprise materials that filter or shape light in another way. It may also be possible that some sections 120 comprise a phosphor or filter material while other sections 120 are completely transparent or devoid of a phosphor or filter material.
Where at least some of the sections 120 comprise a phosphor material, the phosphor material employed may be provided to convert the light 116 emitted by the light source 112 from one color into another color, for example by absorbing light of a predetermined frequency and/or emitting light of a predetermined frequency. More specifically, the phosphor material used in the shaft 104 may comprise a phosphor powder, a resin (e.g., resin A), and a hardener for the resin (e.g., hardener for resin A). Examples of the types of resin that may be used as resin A include, without limitation, urethane based copolymers and polyester resin based copolymers. The hardeners for the resin may correspond to thermal, ultraviolet, or chemical-based hardeners that, when subjected to the appropriate environment (e.g., heat, light, chemical, etc.) cause the resin to cure or substantially harden. In some embodiments, the resin and the resin hardener provided in the phosphor material may be substantially clear or translucent.
The phosphor component of the material in the shaft 104 may correspond to any type of known phosphor or combination of phosphor compounds. More specifically, the phosphor included in the phosphor material may include, without limitation, one or both of a copper-activated zinc sulfide and a silver-activated zinc sulfide (e.g., zinc sulfide silver). The host materials used for the phosphor may include any one or combination of oxides, nitrides and oxynitrides, sulfides, selenides, halides or silicates of zinc, cadmium, manganese, aluminum, silicon, and various rare earth metals. It may also be desirable to include other materials (such as nickel) to quench the afterglow and shorten the decay part of the phosphor emission characteristics.
In a very specific, but non-limiting example, the light source(s) 112 may correspond to a blue or Ultraviolet-emitting LEDs and the phosphor materials of each section 120 may comprise any material or combination materials (using the same or different combination of materials described above) that emit at longer wavelengths than is produced by the light source(s) 112, thereby giving a full spectrum of visible light (e.g., white light). In other embodiments, some of the sections 120 may comprise phosphor materials that, when excited, emit light of a first wavelength while other sections may comprise phosphor materials that, when excited, emit light of a second wavelength.
In some embodiments, the shaft 104 may be configured to rotate or move relative to the core 108. If the shaft 104 comprises a number of sections 120 having different optical properties (e.g., different phosphor materials, different filter materials, different light-shaping properties, etc.), then the rotation of the shaft 104 relative to the core 108 may help to blend the excited photoluminescence of each section 120. This may help in the production of white light or it may help to create other lighting conditions.
Another advantage to providing the phosphor material in the shaft 104, is that the phosphor material can be physically separated from the primary source of heat in the illumination device 100—the light source(s) 112. By maintaining a gap between the light source(s) 112 and the shaft 104, the phosphor material can avoid the unnecessary exposure to heat, which would eventually lead to phosphor degradation. Furthermore, since the core 108 is acting as the primary heat sink in the illumination device 100, the amount of heat radiating toward the shaft 104 can be minimized.
As can be seen in
In some embodiments, the shaft motor 204 may be a relatively simple device that simply rotates the shaft 104 at a predetermined speed when activated. In some embodiments, the shaft motor 204 may be activated by a simple switch that is either on the shaft motor 204, that is remotely controlled, or that is connected to a wall switch that also controls activation of the light source(s) 112.
In more elaborate embodiments, the shaft motor 204 may include a logic circuit that enables an intelligent control of the shaft 104 rotation. Specifically, the shaft motor 204 may be configured to automatically alter the speed of shaft 104 rotation based on a predetermined timing pattern (e.g., to automatically and continuously create different lighting effects). In other embodiments, the shaft motor 204 may be connected to one or more light sensors that detect light emitted by the illumination device 100. For example, the shaft motor 204 may be connected to environmental or ambient light sensors that detect the light emitted by the illumination device 100 and/or other light in a room in which the illumination device 100 is mounted. Based on the light detected at the light detectors, the shaft motor 204 may change the speed at which the shaft 104 rotates, the direction in which the shaft 104 rotates, whether the shaft 104 rotates at all, and the like.
When the shaft 104 comprises different sections 120 having different materials, the rotation of the shaft 104 can facilitate the creation of different lighting effects and/or the creation of white light. In some embodiments, the shaft 104 may include irregular, linear, or mosaic phosphor patterns and the rotation of the shaft 104 relative to the core 108 may take advantage of the phosphor patterning in the shaft 104 to create unique lighting conditions.
In some embodiments, the shaft 104 may be configured to be removed from the illumination device 100. In other words, the shaft 104 may be removed and possibly replaced with other shafts 104 having different properties. Variants of the types of shafts 104 that may be utilized in accordance with embodiments of the present disclosure will now be described.
The shafts 104 depicted in
It should also be appreciated that any combination of shaft 104 configuration shown in
With reference now to
Before, during, or after step 704, the selected shaft 708 may be prepared (step 708). In some embodiments, a molding process may be used to manufacture the shaft. In some embodiments, a printing or layer-deposition process may be performed to create a phosphor layer 508 on a shaft substrate 504.
The shaft 104 may then be positioned about the core 108 (step 712). In some embodiments, the core 108 is positioned within the shaft 104. This may be done either during manufacture or by the end-consumer. As noted above, the shaft 104 may be designed for easy replacement by other shafts 104 (e.g., an end-consumer could slide the shaft 104 over the core 108).
Once the shaft 104 has been positioned relative to the core 108 as desired, the illumination device 100 may be placed into the desired position (e.g., it could be placed into a lighting receptacle to replace an old illumination device, such as one according to the present disclosure or an older type of illumination device). The light source(s) 112 may then be activated (e.g., by flipping a switch, pressing a button, or the like) either directly at the illumination device 100, via remote control, or via a wall switch (step 716). Activation of the light source(s) 112 may cause the light source(s) 112 to begin emitting light 116 toward the shaft 104. Depending upon type of shaft 104 used to surround the light source(s) 112, the emitted light 116 may activate some phosphor material in the shaft 104.
In some embodiments, the shaft 104 can be optionally rotated relative to the core 108 (step 720). This step can be done in response to activating the light source(s) 112 or in the absence of illuminating the light source(s) 112. Where rotation of the shaft 104 is performed the lighting conditions about the illumination device 100 may also be optionally monitored and the rotation of the shaft (speed and/or direction) can be controlled based on the detected lighting conditions (step 724).
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.
