Patent Application
20120007486
Incandescent light bulbs are a source of electric light that creates light by running electricity through a resistive filament, thereby heating the filament to a very high temperature, so that it glows and produces visible light. Incandescent bulbs are made in a wide range of sizes and voltages, from 1.5 volts to about 300 volts. The bulbs consist of a generally glass or plastic enclosure with a filament of tungsten wire inside the bulb through which an electrical current is passed. Incandescent lamps are designed as direct “plug-in” components that mate with a lamp socket via a threaded Edison base connector (sometimes referred to as an “Edison base” in the context of an incandescent light bulb), a bayonet-type base connector (i.e., bayonet base in the case of an incandescent light bulb), or other standard base connector to receive standard electrical power (e.g., 120 volts A.C., 60 Hz in the United States, or 230V A.C., 50 Hz in Europe, or 12 or 24 or other D.C. voltage). The base provides electrical connections to the filament. Usually a stem or glass mount anchors to the base, allowing the electrical contacts to run through the envelope without gas/air leaks.
With reference to
Incandescent light bulbs are widely used in household and commercial lighting, for portable lighting, such as table lamps, car headlamps, flashlights, and for decorative and advertising lighting. However, incandescent light bulbs are generally inefficient in terms of energy use and are subject to frequent replacement due to their limited lifetime (about 1,000 hours). Approximately 90% of the energy input is emitted as heat. These lamps are gradually being replaced by other, more efficient types of electric light such as fluorescent lamps, high-intensity discharge lamps, light emitting diodes (LEDs), etc. For the same energy input, these technologies give more visible light and generate much less heat. Particularly, LEDs consume a fraction of the energy used to illuminate incandescent bulbs and have a much longer lifetime (e.g. 50,000 to 75,000 hours). Furthermore, LED light sources are a very clean “green” light source and also provide good color reproduction.
However, a drawback of LED light bulbs is that they have a very limited tolerance to high temperature and their efficiency falls as the temperature rises. The LED devices cannot be operated at the temperature of an incandescent filament (rather, the operating temperature should be around room temperature). The lower operating temperature also reduces the effectiveness of radiative cooling. Current LED lamps have trouble with heat dissipation, since the heat exchange occurs in an enclosed volume. LEDs are not incorporated as part of the outer bulb; therefore, their housing had to be used as a heat sink. In a usual approach, the base of the LED replacement lamp included (in addition to the Edison base connector and the electronics) a relatively large mass of heat sinking material positioned such that it was contacting or otherwise in good thermal contact with the LED device(s).
Another issue is that unlike an incandescent filament, an LED chip or other solid state lighting device typically cannot be operated efficiently using standard 120V or 230V A.C. power. Rather, on-board electronics are typically provided to convert the A.C. input power to D.C. power of lower voltage amenable for driving the LED chips. As an alternative, a series string of LED chips of sufficient number can be directly operated at 120V or 230V, and parallel arrangements of such strings with suitable polarity control (e.g., Zener diodes) can be operated at 120V or 230V A.C. power, albeit at substantially reduced power efficiency. In either case, the electronics constitute additional components of the lamp base as compared with the simple Edison base used in integral incandescent or halogen lamps.
Accordingly, it is desirable to provide an LED light bulb with improved heat management and electronics that may be used as a replacement for a typical incandescent light bulb.
In certain embodiments disclosed herein as illustrative examples, an LED light bulb is provided that includes a base providing an electrical connection and a substantially hollow envelope extending from the base. The light bulb further includes a metal space separator having a top side, bottom side and side wall that has a plurality of holes. Opposite holes are connected by at least one channel that extends the length of the separator, such that air can pass through the separator. At least one LED is mounted on the separator in electrical connection with the base connector.
In certain embodiments disclosed herein as illustrative examples, an LED lamp is provided that includes an LED-based light source and an Edison-type base connector. The base is configured to electrically power the LED-based light source using electrical power received from the base connector. A first envelope half is provided and includes a first end that attaches to the base and a second end that opens in the opposite direction. A generally circular and planar separator is included that has a top side, a bottom side, and a sidewall. The second end of the first envelope half is mated to the bottom side of the separator. A second envelope half is adapted to attach to the top side of the separator. The separator includes a plurality of interior channels that extend between openings in the side wall. Additionally, at least one LED is mounted on the separator.
In yet another embodiment a candle-shaped LED light bulb for use as a replacement light bulb for an incandescent light bulb is disclosed. The light bulb includes an LED light source, a base, a light-diffusing envelope including a first envelope half and a second envelope half. The light bulb further includes a metal space separator having a top side and a bottom side. Each of the top side and the bottom side include a raised lip portion along the outer edge of the separator. The first envelope half has a first end that is attached to the base and a second end that is mated with to the bottom side. The second half is dome-like with an open end that is mated with the top side of the separator. At least one of said second end and said open end include ridges adapted to press-fit with said raised lip portions, creating an air-tight seal. The separator includes a plurality of holes disposed in the sidewall, oriented such that pairs of holes are directly across the length of the separator from one another and connected by a channel that extends the length of said separator, such that air can pass through the separator.
The invention may take form in various components and arrangements of components, and in various process operations and arrangements of process operations. The drawings are only for purposes of illustrating preferred embodiments and are not to be construed as limiting the invention.
With reference to
In one embodiment, the LED light bulb includes a substantially hollow light transmissive envelope 33 extending upwardly from the base 21 that preferably diffuses light. The envelope 33 may be a glass element, although an envelope of another light-transmissive material such as plastic or other material is also contemplated. The surface of the envelope 33 may diffuse light inherently, or can be made diffusive in various ways, such as: frosting or other texturing to promote light diffusion; coating with a light-diffusive coating such as enamel paint, or a Soft-White or Starcoat™ diffusive coating (available from General Electric Company, New York, USA) of a type used as a light-diffusive coating on the glass envelopes of some incandescent or fluorescent light bulbs; embedding light-scattering particles in the glass, plastic, or other material of the envelope 33; various combinations thereof; or so forth.
According to a preferred embodiment, the light transmissive envelope 33 is dissected into two halves, a first half 29 and a second half 41. The first half 29 includes two ends 30, 31. A first end 30 attaches to the base 21 and the second end 31 extends upwardly. A metal space separator 25 may be mechanically fixed to the second end 31, such that the separator 25 creates a seal, effectively securing the second end 31 in place. Although metal space separator 25 is generally described herein as a disc, the separator may take on any shape depending on the desired application.
An LED light source 37, 36 is included in the metal space separator, preferably being fitted on the top side of the separator 25, although the LED may alternatively or additionally be mounted on the bottom side of the separator. Depending on desired intensity, the LED light source may include one or more LEDS (not shown) fitted into the top side 43 of the separator 25 and, therefore, the LED(s) face into the interior of the second envelope half 41 and emit light into the interior of the envelope 33. The separator 25 is made of heat conductive material and may act as a heat sink, absorbing and dissipating heat from the one or more LEDs to the ambient air. The heat sinking separator 25 ensures that the temperature of the LED lamp does not increase to a point that the lamp becomes inefficient. Additionally, since the separator 25 acts as a heat sink for the light bulb, the LED light bulb does not rely upon the lighting socket for heat sinking. As such, the LED bulb of
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In one embodiment, detailed in
The exemplary embodiment has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
