Phosphor deposition system for LEDs
A method to produce a light-emitting device package includes mounting junctions on pads of a metalized substrate, where the junctions are at least partially electrically insulated from each other, and forming wavelength converters, where each wavelength converter is located over a different junction and separated by a gap from neighboring wavelength converters.
1. A method for making a light-emitting device comprising: arranging a plurality of semiconductor diodes (LEDs) on a metalized substrate to form a first group of LEDs electrically connected to each other and a second group of LEDs electrically connected to each other, the first and second groups of LEDs forming a LED array; performing electrophoretic deposition (EPD) to deposit wavelength converters on the first group of LEDs by applying a first voltage to the first group of LEDs; and performing EPD to deposit wavelength converters on the second group of LEDs by applying a second voltage to the second group of LEDs, and further wherein performing EPD to deposit wavelength converters on the first group of LEDs comprises applying a third non-zero voltage to the second group of LEDs.
2. The method of claim 1 wherein performing EPD to deposit wavelength converters on the second group of LEDs comprises applying a fourth non-zero voltage to the first group of LEDs.
3. The method of claim 1 wherein the wavelength converters deposited on the first group of LEDs differ in composition from the wavelength converters deposited on the second group of LEDs.
4. The method of claim 3 wherein the wavelength converters deposited on the first group of LEDs each comprise a cool-white phosphor layer, the wavelength converters deposited on the second group of LEDs each comprise a warm-white phosphor layer, and the LEDs are blue emitting LEDs.
5. The method of claim 1 wherein the third non-zero voltage is a voltage with an opposite polarity to the first voltage.
6. The method of claim 1 wherein LEDs in the first group of LEDs are electrically connected in parallel.
7. The method of claim 1 wherein LEDs in the first group of LEDs are electrically connected in series.
8. The method of claim 1 wherein performing EPD to deposit the wavelength converters on the first group of LEDs comprises depositing the wavelength converters in a checkboard pattern.
9. The method of claim 1 wherein the first voltage is the same as the second voltage.
10. A method for making a light-emitting device comprising: arranging a plurality of LEDs on a metalized substrate to form a first group of LEDs electrically connected to each other and a second group of LEDs electrically connected to each other, the first and second groups of LE Ds forming a LED array; performing electrophoretic deposition (EPD) to deposit wavelength converters on the first group of LEDs but not on the second group of LEDs by applying a first voltage to the first group of LEDs, wherein performing EPD to deposit wavelength converters on the first group of LEDs comprises applying a second non-zero voltage to the second group of LEDs.
11. The method of claim 10 wherein the second non-zero voltage is a voltage with an opposite polarity to the first voltage.
12. The method of claim 10 wherein LEDs in the first group of LEDs are electrically connected in parallel.
13. The method of claim 10 wherein performing EPD to deposit the wavelength converters on the first group of LEDs comprises depositing the wavelength converters in a checkboard pattern.