Wafer level phosphor coating technique for warm light emitting diodes
First Claim
1. A light emitting diode (LED) chip wafer, comprising:
- a plurality of LEDs on a wafer;
a first conversion layer on at least some of said LEDs, said first conversion layer comprising a first conversion material having an associated emission spectrum;
a second conversion layer comprising a second conversion material having an associated excitation spectrum and arranged on said first conversion layer, said second conversion material being different than said first conversion material, wherein said first conversion material emission spectrum does not substantially overlap with said second conversion material excitation spectrum; and
a plurality of pedestals, each of which is in electrical contact with one of said plurality of LEDs, at least some of said pedestals extending through said first and second conversion layers and exposed at the top surface of said layers.
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Abstract
Methods for wafer level fabricating of light emitting diode (LED) chips are disclosed with one embodiment of a method according to the present invention comprising providing a plurality of LEDs and then coating of the LEDs with a layer of first conversion material so that at least some light from the LEDs passes through the first conversion material. The light is converted to different wavelengths of light having a first conversion material emission spectrum. The LEDs are then coated with a layer of second conversion material arranged on the first layer of conversion. The second conversion material has a wavelength excitation spectrum, and at least some light from the LEDs passes through the second conversion material and is converted. The first conversion material emission spectrum does not substantially overlap with the second conversion material excitation spectrum. Methods according to the present invention can also be used in wafer level fabrication of LED chips and LED packages with pedestals for electrically contacting the LEDs through the conversion coatings.
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Citations
21 Claims
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1. A light emitting diode (LED) chip wafer, comprising:
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a plurality of LEDs on a wafer; a first conversion layer on at least some of said LEDs, said first conversion layer comprising a first conversion material having an associated emission spectrum; a second conversion layer comprising a second conversion material having an associated excitation spectrum and arranged on said first conversion layer, said second conversion material being different than said first conversion material, wherein said first conversion material emission spectrum does not substantially overlap with said second conversion material excitation spectrum; and a plurality of pedestals, each of which is in electrical contact with one of said plurality of LEDs, at least some of said pedestals extending through said first and second conversion layers and exposed at the top surface of said layers. - View Dependent Claims (2)
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3. A light emitting diode (LED) chip, comprising:
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an LED; a pedestal in electrical contact with said LED; a layer of first conversion material on said LED, said layer of first conversion material having an associated emission spectrum; and a layer of second conversion material on said layer of first conversion material, said second conversion material being different than said first conversion material and having an associated excitation spectrum, wherein said first conversion material emission spectrum does not substantially overlap with said second conversion material excitation spectrum, wherein said pedestal is configured to provide electrical connection to said LED. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A light emitting diode (LED) package comprising:
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an LED and a pedestal in electrical contact with said LED; a coating of first conversion material on said LED, said first conversion material having an associated emission spectrum; a coating of second conversion material on said coating of first conversion material, said second conversion material having an associated excitation spectrum, wherein said first conversion material emission spectrum does not substantially overlap with said second conversion material excitation spectrum; a package lead in electrical connection with said pedestal; and an encapsulation over said LED chip and electrical connection. - View Dependent Claims (16)
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17. A light emitting diode (LED) chip wafer, comprising:
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a plurality of LEDs on a wafer; a plurality of pedestals each of which is in electrical contact with one of said LEDs; a layer of first conversion material on at least some of said LEDs, said first conversion material having an associated emission spectrum; and a layer of second conversion material on said layer of first conversion material, said second conversion material being different than said first conversion material and having an associated excitation spectrum, wherein said first conversion material emission spectrum does not substantially overlap with said second conversion material excitation spectrum. - View Dependent Claims (18, 19, 20, 21)
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Specification