Light emitting packages and methods of making same
View Patent ↗In a light emitting package ( 8 ), at least one light emitting chip ( 12, 14, 16, 18 ) is supported by a board ( 10 ). A light transmissive encapsulant ( 30 ) is disposed over the at least one light emitting chip and over a footprint area ( 32 ) of the board. A light transmissive generally conformal shell ( 40 ) is disposed over the encapsulant and has an inner surface ( 44 ) spaced apart by an air gap (G) from, and generally conformal with, an outer surface ( 34 ) of the encapsulant. At least one phosphor ( 50 ) is disposed on or embedded in the conformal shell to output converted light responsive to irradiation by the at least one light emitting chip. A thermally conductive filler material disposed in the generally conformal shell ( 40 ) is effective to enhance a thermal conductivity of the composite shell material to a value higher than 0.3 W/(m·K).
1. A lighting package comprising:
at least one light emitting chip;
a board supporting the at least one light emitting chip;
a light-transmissive encapsulant disposed over the at least one light emitting chip and over a footprint area of the board;
a light-transmissive generally conformal shell disposed over the light-transmissive encapsulant and having an inner surface spaced apart by an air gap from and generally conformal with an outer surface of the light-transmissive encapsulant; and
a phosphor disposed on or embedded in the conformal shell and configured to output converted light responsive to irradiation by the at least one light emitting chip;
wherein the light-transmissive encapsulant and conformal shell are generally hemispherical and the footprint area of the board is generally circular with a radius about equal to a radius of the hemispherical light-transmissive encapsulant and the air gap between the outer surface of the light-transmissive encapsulant and the inner surface of the conformal shell is at least about 0.5 millimeter.
2. The lighting package as set forth in claim 1 , wherein the generally circular footprint area of the board extends at least two millimeters beyond an outermost edge of the at least one light emitting chip.
3. The lighting package as set forth in claim 2 , wherein the at least one light emitting chip includes a plurality of light emitting chips arranged on the board with an inter-chip spacing of at least about one times a principal lateral dimension of a largest chip of the plurality of light emitting chips.
4. The lighting package as set forth in claim 1 , wherein the at least one light emitting chip is configured to emit violet or ultraviolet radiation and the phosphor is configured to convert substantially all of the radiation emitted by the at least one light emitting chip into converted light in the visible wavelength range.
5. The lighting package as set forth in claim 1 , wherein the at least one light emitting chip is configured to emit radiation having a spectrum that is principally below 425 nanometers in wavelength, and the phosphor is configured to convert substantially all of the radiation emitted by the at least one light emitting chip into white or substantially white light.
6. The lighting package as set forth in claim 1 , wherein the conformal shell is formed of a material having a thermal conductivity that is higher than 0.3 W/(m·K).
7. The lighting package as set forth in claim 6 , wherein the conformal shell is formed of a material having a thermal conductivity that is higher than 1 W/(m·K).
8. The lighting package as set forth in claim 1 , further comprising:
a layer of legend ink disposed over at least most of the generally elliptical or circular footprint area of the board.
9. A lighting package comprising:
one or more light emitting chips;
a board supporting the one or more light emitting chips;
a light-transmissive encapsulant disposed over the one or more light emitting chips and over a footprint area of the board; and
a remote phosphor disposed in a phosphor layer located remote from the one or more light emitting chips and proximate to an outer surface of the light-transmissive encapsulant, the remote phosphor configured to output converted light responsive to irradiation by the one or more light emitting chips;
wherein a heat-sinking component in contact with substantially the whole phosphor layer comprises a material having a thermal conductivity that is higher than 0.3 W/(m·K).
10. The lighting package as set forth in claim 9 , wherein the heat-sinking component includes a light-transmissive generally conformal shell, and the light-transmissive generally conformal shell comprises:
a thermally conductive filler material disposed in the light-transmissive generally conformal shell such that the light-transmissive generally conformal shell is made of a composite shell material having thermal conductivity higher than 1 W/(m·K).
11. The lighting package as set forth in claim 9 , comprising wherein the heat-sinking component includes:
a generally conformal glass shell disposed over the light-transmissive encapsulant, the generally conformal glass shell comprising glass and a thermally conductive filler material disposed in the glass wherein the glass with the thermally conductive filler material has a thermal conductivity higher than 0.3 W/(m·K).
12. The lighting package as set forth in claim 9 , wherein the heat-sinking component in contact with substantially the whole phosphor layer comprises nanometer-sized thermally conductive filler particles with particle size less than 100 nm.