Patent Grant
8384300
The present invention relates generally to lighting techniques. More particularly, the present invention provides a method and device using an electrodeless plasma lighting device having one of a plurality of base configurations. Merely by way of example, such configurations can include at least an Edison base or a mogul base, but can be others.
From the early days, human beings have used a variety of techniques for lighting. Early humans relied on fire to light caves during hours of darkness. Fire often consumed wood for fuel. Wood fuel was soon replaced by candles, which were derived from oils and fats. Candles were then replaced, at least in part by lamps. Certain lamps were fueled by oil or other sources of energy. Gas lamps were popular and still remain important for outdoor activities such as camping. In the late 1800, Thomas Edison, who is one of the greatest inventors of all time, conceived the incandescent lamp, which uses a tungsten filament within a bulb, coupled to a pair of electrodes. Many conventional buildings and homes still use the incandescent lamp, commonly called the Edison bulb. Although highly successful, the Edison bulb consumed much energy and was generally inefficient.
Fluorescent lighting replaced incandescent lamps for certain applications. Fluorescent lamps generally consist of a tube containing a gaseous material (typically Argon) and Mercury, which is coupled to a pair of electrodes. The electrodes are coupled to an electronic ballast, which helps ignite the discharge from the fluorescent lighting. Conventional building structures often use fluorescent lighting, rather than the incandescent counterpart. Fluorescent lighting is much more efficient than incandescent lighting, but often has a higher initial cost.
Shuji Nakamura pioneered the efficient blue light emitting diode, which is a solid state lamp. The blue light emitting diode forms a basis for the white solid state light, which is often a blue light emitting diode within a bulb coated with a yellow phosphor material. Blue light excites the phosphor material to emit white lighting. The blue light emitting diode has revolutionized the lighting industry to replace traditional lighting for homes, buildings, and other structures.
Another form of lighting is commonly called the electrodeless lamp, which can be used to discharge light for high intensity applications. Frederick Espiau was one of the pioneers that developed an improved electrodeless lamp. Such electrodeless lamp relied upon a solid ceramic resonator structure, which was coupled to a fill enclosed in a bulb. The bulb was coupled to the resonator structure via RF feeds, which transferred power to the fill to cause it to discharge high intensity lighting. Although somewhat successful, the electrodeless lamp still had many limitations, including the inability of the lamp to fit into standard light sockets such as the Edison socket or mogul socket.
From the above, it is seen that improved techniques for lighting are highly desired.
According to the present invention, techniques generally for lighting techniques are provided. More particularly, the present invention provides a method and device using an electrodeless plasma lighting device having one of a plurality of base configurations. Merely by way of example, such configurations can include at least an Edison base, but can be others.
In a specific embodiment, the present invention provides an RF electrode-less plasma lighting device. The device has a base member, which includes an outer region capable of being coupled to first AC potential and an inner region capable of being coupled to a second AC potential. The device also has an AC to DC converter mechanically and integrally coupled to the base member. In a specific embodiment as an example only, the converter is a switching converter, but can be others. In a specific embodiment, the AC to DC converter has first AC contact region and a second AC contact region. In a specific embodiment, the first AC contact region is electrically coupled to the first potential and the second AC contact region is coupled to the second potential. In a specific embodiment, the AC to DC converter has a first DC output and a second DC output. The device also has an RF module mechanically and integrally coupled to the base member. In a preferred embodiment, the RF module has an RF source. The RF module has a first DC input and a second DC input. The first DC input of the RF module is coupled to the first DC output of the AC to DC converter and the second DC input of the RF module is coupled to the second DC output of the AC to DC converter. The RF source has an output and optionally has an input. In a specific embodiment, the device has an RF electrode-less plasma lighting assembly integrally coupled to the base member. The RF electrode-less plasma lighting assembly has an RF input, which is coupled to the output of the RF source.
In an alternative specific embodiment, the present invention provides an RF electrode-less plasma lighting device. The device has a base member, which has an outer region capable of being coupled to first AC potential and an inner region capable of being coupled to a second AC potential. In a preferred embodiment, the device has an RF module mechanically and integrally coupled to the base member. The RF module has an RF source, which has an output. The RF module has a first AC input and a second AC input. The first AC input of the RF module is coupled to the first AC potential and the second AC input of the RF module is coupled to the second AC potential. In a specific embodiment, the present device has an RF electrode-less plasma lighting assembly integrally coupled to the base member. The RF electrodeless plasma lighting assembly has an RF input, which is coupled to the output of the RF source.
Benefits are achieved over existing techniques using the present invention. In a specific embodiment, the present invention provides a method and device having configurations of input, output, and feedback coupling elements that provide for electromagnetic coupling to the bulb whose power transfer and frequency resonance characteristics in a suitable form factor. In a preferred embodiment, the present invention provides a method and configurations with an arrangement that provides for improved manufacturability as well as design flexibility. Other embodiments may include integrated assemblies of the output coupling element and bulb that function in a complementary manner with the present coupling element configurations and related methods for conventional lighting applications to replace the Edison socket or mogul socket. In a specific embodiment, the present method and resulting structure are relatively simple and cost effective to manufacture for commercial applications as well as simple to install into existing fixtures and sockets with minimal or no change to the existing fixtures. Depending upon the embodiment, one or more of these benefits may be achieved. These and other benefits may be described throughout the present specification and more particularly below.
The present invention achieves these benefits and others in the context of known process technology. However, a further understanding of the nature and advantages of the present invention may be realized by reference to the latter portions of the specification and attached drawings.
A more complete understanding of the present invention and its advantages will be gained from a consideration of the following description of preferred embodiments, read in conjunction with the accompanying drawings provided herein. In the figures and description, numerals indicate various features of the invention, and like numerals referring to like features throughout both the drawings and the description.
According to the present invention, techniques generally for lighting are provided. More particularly, the present invention provides a method and device using an electrodeless plasma lighting device having one of a plurality of base configurations. Merely by way of example, such configurations can include at least Edison base or mogul base, but can be others.
Many advantages are created by utilizing an electrodeless plasma lamp integrated with a base. First, the compact design of the device leads to easier manufacturing at larger volumes and lower cost. Furthermore, the electrodeless plasma lamp has significantly higher efficacy than the typical incandescent bulb, while generating much higher luminous intensity. In addition the integrated plasma lamp assembly can fit into existing fixtures and lamp sockets with very little change or no change at all to existing fixtures. Finally, the electrodeless plasma lamp integrated with a base, has a much longer lifetime than typical incandescent bulbs.
An AC to DC converter is integrated within the base member, and has a first AC contact region and a second AC contact region. The method by which the RF source within the socket base is powered is shown in the simplified block diagram of
The RF module includes two inputs, the first input electrically coupled to the first DC potential output, and the second input electrically coupled to the second DC potential output. The RF module includes an RF source that is powered through the first and second DC potentials. The RF source has an output that is coupled to the RF input coupling element of the lamp body, which is in turn used to drive the entire assembly to resonate at the corresponding resonant frequency. The RF source can be in a frequency between about 10 MHz and 20 GHz. As mentioned previously, the RF module also includes an RF amplifier that has a gain of at least 20 dB and an efficiency of at least 75% but preferably higher. The integrated base electrodeless plasma lamp can also include a heat sink coupled to the RF source. The heat sink is used to dissipate thermal energy that is generated by the RF source, away from the RF source. Alternatively, the heat sink can be coupled to the base member to allow for the dissipation from the heat sink to the base member. Incorporating the heat sink within the device ensures that the RF source does not fail due to the buildup of thermal energy, thereby leading to improved device performance.
The present invention employs a lamp body 600, whose outer surface 601 is electrically conductive and is connected to the second DC input.
The bottom of the assembly 100, output coupling-element 120, is coupled to the second DC input to the waveguide body 600 and its conductive surface 601. The luminous output from the bulb is collected and directed by an external reflector 670, which is either electrically conductive or if it is made from a dielectric material has an electrically conductive backing, and which is attached to and in electrical contact with the body 600. The lamp apparatus includes a reflector 670 that is depicted as parabolic in shape with bulb 130 positioned near its focus. Those of ordinary skill in the art will recognize that a wide variety of possible reflector shapes can be designed to satisfy beam-direction and illumination requirements. In a specific embodiment, the shapes can be conical, convex, concave, trapezoidal, pyramidal, or any combination of these, and the like.
The lamp is driven by a separate oscillator 205 conductively connected with RF amplifier input 211 of the RF amplifier 210. RF amplifier output 212 is conductively connected with input coupling-element 630, also referred to as the RF source probe, which delivers RF power to the lamp/output coupling-element assembly 100, through the output coupling element 120, also referred to as the first probe. The resonant characteristics of the coupling between the input coupling-element 630 and the output coupling-element in the bulb/output coupling-element assembly 100 are frequency-matched to the RF source to optimize RF power transfer. Of course, there can be other variations, modifications, and alternatives.
The lamp/output coupling element assembly consists of a solid metal (metal post) 120 recessed at the top to receive the gas-filled vessel 130. The other end of the coupling-element is grounded to lamp body at surface 101. The top portion of the metal post is surrounded by metal ring. A thin layer of dielectric material or refractory metal such as molybdenum can be used as interface between the bulb and the metal post. Alternatively the top part of the metal post or all of the metal post can be made from a refractory metal with its outer surface covered with a layer of metal with high electrical conductivity such as silver or copper. The metal post can also be hollow inside. This diagram is merely an example, which should not unduly limit the scope of the claims herein. Examples of plasma lamp devices are described in “Electrodeless Lamps with Externally-Grounded Probes and Improved Bulb Assemblies,” in the names of Espiau, Frederick M, Brockett, Timothy J., and Matloubian, Mehran, as listed as U.S. Ser. No. 61/075,735 filed Jun. 25, 2008, commonly assigned, and hereby incorporated by reference herein. Other examples include U.S. Pat. No. 7,362,056, among others, which are assigned to Luxim Corporation of Sunnyvale, Calif. One of ordinary skill in the art would recognize other variations, modifications, and alternatives.
A significant advantage of the invention is that the input coupling-element 630 and the bulb/output coupling-element assembly 100 are respectively connected to the second DC input at planes 631 and 101, which are coincident with the outer surface of the body 600. This eliminates the need to fine-tune their depth of insertion into the lamp body—as well as any sensitivity of the RF coupling between them to that depth—simplifying lamp manufacture, as well as improving consistency in lamp brightness yield.
In an alternate embodiment of the preset invention shown in
The RF module includes an RF source. The RF module can include an RF amplifier with a gain that is at least 20 dB and an efficiency level of at least 75% but preferably higher. Unlike the previous embodiment, the RF source is coupled directly to the first and second AC potential inputs, to adequately power the RF source. A heat sink can be incorporated with the RF power source to efficiently dissipate thermal energy that is generated by the RF power source, away from the RF power source. The RF power source, in turn, outputs RF signals ranging from about 10 MHz to 20 GHz. The RF module is coupled to the RF input coupling element of the lamp, where the output signals that are generated by the RF source are used to resonate the entire RF plasma lamp device at its resonant frequency, thereby creating a plasma within the bulb and subsequently creating a luminous output.
The bulb includes a gas-filled vessel that is made of a suitable material such as quartz or other transparent or translucent material. The gas-filled vessel is filled with an inert gas such as Argon and a fluorophor or light emitter such as Mercury, Sodium, Dysprosium, Sulfur or a metal halide salt such as Indium Bromide, Scandium Bromide, or Cesium Iodide (or it can simultaneously contain multiple fluorophors or light emitters). The gas-filled vessel can also includes a metal halide, or other metal pieces that will discharge electromagnetic radiation according to a specific embodiment. Of course, there can be other variations, modifications, and alternatives.
In an alternate embodiment of the present invention, the RF module consists of a semiconductor device that acts as the RF source. The semiconductor device has a breakdown voltage that is at least greater than 100 V and preferably greater than 200 V. The semiconductor device can be silicon-based transistor or thyristor. Alternatively, the semiconductor device can be a silicon-carbide based transistor or thyristor, a gallium-nitride based transistor or thyristor, or a gallium-arsenide based transistor or thyristor. By using such semiconductor devices in the RF module, a further reduction in sizes of the overall plasma lamp lighting device is provided.
In an alternate embodiment of the present invention, an external AC-to-DC converter is used to provide DC input to the socket and through the socket to the base of the integrated plasma lamp. The DC input will provide power to the RF module which then provides RF power to the input of the resonator/waveguide to light up the bulb.
While the above is a full description of the specific embodiments, various modifications, alternative constructions and equivalents may be used. Therefore, the above description and illustrations should not be taken as limiting the scope of the present invention which is defined by the appended claims.
This application claims priority to U.S. Provisional Patent Application No. 61/239,056, filed Sep. 1, 2009, entitled “INTEGRATED RF ELECTRODELESS PLASMA LAMP DEVICE AND METHODS” which is commonly owned and incorporated by reference in its entirety herein for all purposes.
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