Patent Application
20090135597
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The present invention relates to linear light fixtures, and more particularly to replacements for incandescent light bulbs adapted for use with such light fixtures.
Existing light fixtures using linear incandescent sources provide general illumination and accent illumination for both outdoor and indoor applications. Although relatively efficient optically, the light source is electrically inefficient. For example, current linear incandescent lamps only produce between 11-15 lumens per 1 watt of energy. Therefore, in order to get a usable amount of light, high wattage lamps are often used.
Further, incandescent linear sources produce a large amount of radiant heat while producing a small amount of visible light. Thus, linear incandescent sources can run at very high temperatures, adding burden to the cooling system in indoor applications, in addition to creating a fire hazard. Particularly as a result of the fire hazard, restrictions have been placed in many fixtures using these sources to prevent fires.
Although the lamps are typically sold in high wattages, the form factor is small, with the diameter typically being only ¼″, allowing for good optical control and small fixture sizes (with small fixture sizes allowing for a lower cost, more versatile product).
Thus, there has long been a need for a light source which produces a large amount of light in a relatively small linear package without the thermal issues associated with the current incandescent sources.
The present invention is directed toward overcoming one or more of the problems set forth above.
According to one aspect of the present invention, a bulb replacement for an incandescent linear light fixture is provided, including a rigid circuit board, a plurality of LEDs mounted on the front surface of the circuit board, a heat sink mounted to the back surface of the circuit board and adapted to conduct heat from the circuit board and LEDs, and first and second circuit board connectors projecting from one of the circuit board sides. The circuit board connectors are spaced apart so as to be adapted to simultaneously snap-fit in fixture power connectors, respectively, to provide power to the circuit board through the electrical contacts.
In one form of this aspect of the present invention, the circuit board connectors are semicircular about an axis, and are adapted to snap-fit into electrically conductive sockets of the power connectors whereby the circuit board is supported for selective pivoting around the axis to direct light from the LEDs in a selected direction.
In another form of this aspect of the present invention, the heat sink is also the reflector.
In still another form of this aspect of the present invention, the circuit board is adapted to supply constant current to the LEDs.
In yet another form of this aspect of the present invention, the printed circuit board is adapted to supply constant current and constant voltage to the LEDs.
According to yet another form of this aspect of the present invention, the plurality of LEDs are aligned in a linear pattern and comprise first and second sets of LEDs with the LEDs of the first set alternating along the pattern with the LEDs of the second set, the first and second sets of LEDs being on parallel circuits. In a further form, the circuit board is adapted to supply constant current to the LEDs and in a still further form, the circuit board is adapted to supply constant current and constant voltage to the LEDs.
In another aspect of the present invention, a linear light fixture is provided, including a longitudinal base adapted to mount on a flat surface, spaced first and second power connectors with electrical contacts secured to the base, and a longitudinal reflector secured to the base and extending longitudinally in the direction of the surface when the base is mounted to a surface. A replaceable light emitting element includes a rigid circuit board having a front surface and a back surface, a plurality of LEDs mounted on the front surface of the circuit board, a heat sink mounted to the back surface of the circuit board and adapted to conduct heat from the circuit board and LEDs, and first and second circuit board connectors projecting from one of the circuit board sides. The circuit board connectors are spaced apart so as to simultaneously snap-fit in the first and second power connectors, respectively, to selectively provide power to the circuit board through the electrical contacts.
In one form of this aspect of the present invention, the circuit board is longitudinal, and extends longitudinally in the same direction as the reflector.
In another form of this aspect of the present invention, the circuit board connectors are semicircular about an axis, and are adapted to snap-fit into electrically conductive sockets of the power connectors whereby the circuit board is supported for selective pivoting around the axis to direct light from the LEDs in a selected direction. In a further form, the reflector is substantially arcuate about the axis in its longitudinal direction. In still another further form, a pair of insulators are located around the circuit board connectors to prevent electrical shorts with the reflector.
In another aspect of the present invention, a method of lighting a space is provided, including the steps of mounting the linear light fixture as described above to a boundary surface of the space, pivoting the circuit board to direct the LEDs in a selected orientation relative to the reflector, and selectively passing power from the first power connector, through the circuit board, to the second power connector.
An exemplary lamp replacement assembly 10 according to the present invention is illustrated in
The assembly 10 includes a suitable printed circuit board 14 on which a plurality of light emitting diodes (LEDs) 20 are mounted perpendicularly thereon. Advantageously, the LEDs 20 may be arranged at substantially even spacings in a linear arrangement along the top of the circuit board 14, with the printed circuit being suitable to provide parallel circuits with alternating LEDs 20 being on the different ones of the parallel circuits. Thus, by varying the power to each circuit, such as through a control unit, the LEDs may provide different lighting, with the different lighting in all cases nonetheless being substantially uniform along the longitudinal length of the assembly 10. For any selected lighting, the circuit board 14 may be advantageously configured to supply both constant current and constant voltage to the LEDs 20 for ideal lighting effects. However, it should be appreciated that still other LED arrangements may also be provided while incorporating some aspects of the present invention, including using providing different color lighting and providing only one circuit, or more than two parallel circuits.
A heat sink 30 is advantageously mounted to the back surface of the circuit board 14 and is advantageously configured and adapted to conduct heat from the circuit board 14 and LEDs 20. The heat sink 30 may be reflective to facilitate lighting, and also may extend substantially the length of the circuit board 14 and include a plurality of spaced ribs 34 extending longitudinally along the heat sink 30 to facilitate cooling of the assembly 10. A thermally conductive transfer tape 36 or the like (e.g., a thermal pad, thermal grease, or other conformable material) (see
First and second circuit board connectors 40, 42 project from the bottom of the circuit board 14 and include a semicircular cylindrical portion 46, 48 aligned about an axis 50. These connectors 40, 42 may be made, for example, from nickel plated brass. Polycarbonate spacers 54, 56 may also be mounted between the circuit board 14 and the circuit board connectors 40, 42 to control electrical contact and to act as insulators to prevent electrical shorts (such as with adjacent fixture components such as a reflector, described below). Suitable rivets 60 (made, e.g., from aluminum) secure the structure together (see
A light fixture 70 with which the replacement assembly 10 may be used is illustrated in
The size (length) of the replacement assembly 10 may vary depending on the requirements of a particular installation. Further, for longer fixtures 70, a support (not shown) may also be provided between the power connectors 80 to support the replacement assembly 10 from sagging in the middle.
When mounted together, the circuit board connectors 40, 42 and the power connectors 80 selectively provide power to the circuit board 14 through the electrical contacts. Moreover, the semicircular shape of the axially aligned circuit board connectors 40, 42 cooperate with the power connectors so that the circuit board 14 is supported for selective pivoting around the axis 50 to direct light from the LEDs 20 in a selected direction. The curve of the heat sink 30 cooperates with the curve of the reflector 76 to facilitate such variable positioning.
Still further, the circuit board 14 and LED's 20 are located above the power connectors 80, to provide advantageous positioning for the LEDs 20. With the circuit board connectors 40, 42 projecting from the bottom of the circuit board 14 as previously noted, the circuit board 14 may advantageously extend not only over the circuit board connectors 40, 42 and the sockets 84 in which the connectors 40, 42 are snap-fit (i.e., above the connectors 40, 42 and sockets 84, or spaced from the axis 50), but the circuit board 14 may also advantageously extend beyond the connectors 40, 42 and sockets 84. Thus, the circuit board 14 and LEDs 20 will not be restricted in size (e.g., length) by the space between the sockets 84, and the LEDs 20 may be provided not only between the power connectors 80 but also beyond the connectors 80, so that the location of the power connectors 80 does not restrict the length of the light. It should be appreciated, in fact, that the assembly 10 could even be spanned between the power connectors 80 of separate fixtures 70. Further, shadows in the lighting from the LEDs 20 which could arise as a result of positioning the lights in the recessed space between sockets as in the prior art are also eliminated.
In addition to the many above described advantages, it should also be appreciated that lamp replacement assemblies 10 may be advantageously used in place of incandescent linear lamps in light fixtures 70 such as illustrated in
Still other aspects, objects, and advantages of the present invention can be obtained from a study of the specification, the drawings, and the appended claims. It should be understood, however, that the present invention could be used in alternate forms where less than all of the objects and advantages of the present invention and preferred embodiment as described above would be obtained.
