LED-Based Replacement Lamps for Incandescent Fixtures
A luminaire takes the form of a bulb-shaped, LED-based lamp, which can replace a conventional incandescent bulb.
1 . An LED-based illumination structure for replacing an incandescent bulb, the structure comprising:
a base for mating with an incandescent light socket;
a rounded, bulb-shaped waveguide comprising in-coupling, propagation, and out-coupling regions; and
at least one LED disposed for emission into the in-coupling region, whereby light from the at least one LED propagates through the propagation region and is emitted only from the out-coupling region.
2 . The structure of claim 1 wherein the waveguide includes a base edge and a rounded crown portion opposite the base edge, the in-coupling region encompassing the base edge and the out-coupling region encompassing the crown portion.
3 . The structure of claim 2 wherein the waveguide has a length from the base edge to a peak point on the crown portion, the out-coupling region extending over at least half the length.
4 . The structure of claim 1 further comprising a phosphor material, for converting light to a different wavelength, surrounding at least a portion of the out-coupling region.
5 . The structure of claim 4 wherein the phosphor material is within at least a portion of the out-coupling region.
6 . The structure of claim 1 further comprising a heat sink between the base and the waveguide.
7 . The structure of claim 1 further comprising power-conversion and drive circuitry for driving the LED from household current supplied to the base.
8 . The structure of claim 2 further comprising a reflector disposed within and adjacent to the base edge.
9 . The structure of claim 1 further comprising an inner reflector disposed over at least a portion of an inner surface of the waveguide.
10 . The structure of claim 9 wherein the inner reflector extends at least over the inner surface of the out-coupling region.
11 . The structure of claim 2 wherein the at least one LED is embedded inside the base edge.
12 . The structure of claim 2 wherein the at least one LED illuminates through the base edge.
13 . The structure of claim 1 comprising a plurality of LEDs evenly distributed circumferentially around the in-coupling region.
14 . The structure of claim 13 wherein at least one of the LEDs emits light of a color different from that emitted by at least another one of the LEDs.
15 . The structure of claim 1 wherein the at least one LED is a bare light-emitting diode die.
16 . The structure of claim 4 wherein the waveguide surrounds a hollow interior space.
17 . The structure of claim 16 wherein light is emitted from opposed faces of the out-coupling region, light emitted from an exterior face thereof passing through the phosphor and light emitted from an interior face thereof passing into the interior space and through an opposed portion of the out-coupling region.
18 . The structure of claim 4 wherein the phosphor is outside a direct line-of-sight of the at least one LED.
19 . The structure of claim 1 wherein the out-coupling region comprises a plurality of optical elements.
20 . The structure of claim 19 wherein the optical elements comprise at least one of microlenses or scattering particles.