Method and system for dynamic in-situ phosphor mixing and jetting
View Patent ↗A system and method for depositing a phosphor composition onto a light emitting device improves manufacturing yield, simplifies conventional processes, and decreases costs. For example, a method of dispensing a phosphor composition onto a light emitting device includes dispensing a portion of the phosphor composition onto the light emitting device utilizing a plurality of colored phosphor dispensers each for dispensing a respective type of phosphor. Power is applied to the light emitting device to emit light, and a characteristic the light emitted by the light emitting device is detected. Phosphor mixing and phosphor dispensing are dynamically controlled. Therefore the color characteristics of phosphor dispensed on LEDs are consistent. The system and method may also reduce the difference between detected characteristic of the light and a desired characteristic of the light.
1. An apparatus operable in a light-emitting-device-manufacturing system, the apparatus comprising:
dispensing means configured to dispense a composition of a plurality of phosphors onto the light emitting device;
sensing means configured to detect a characteristic of light emitted by the light emitting device;
controlling means configured to adjust relative amounts of respective portions of the composition during dispensation to reduce a difference between the detected characteristic of the light and a desired characteristic of the light, determine whether the detected characteristic of light is within a predetermined range for the desired characteristic of the light,
and iterate dispensing the adjusted composition, detecting the characteristic of light, and adjusting the composition while the detected characteristic of the light is outside of the predetermined range for the desired characteristic of the light,
wherein the dispensing means is further configured to dispense the composition until the total dispensed phosphor composition is one of a predetermined weight or volume while the detected characteristic of the light is within the predetermined range.
2. The apparatus of claim 1 , wherein the desired characteristic of the light comprises at least one of a correlated color temperature (CCT) or a set of coordinates in a color space.
3. The apparatus of claim 2 , wherein the desired characteristic of the light comprises the CCT and the set of coordinates in the color space.
4. The apparatus of claim 1 , wherein the respective portions of the phosphor composition comprise respective colors of phosphor suspended in silicone.
5. The apparatus of claim 4 , wherein the dispensing means is further configured to dispense each respective one of the colors of phosphor utilizing a respective dispensing means configured to dispense a respective color phosphor.
6. The apparatus of claim 4 , wherein the respective portions of the phosphor composition further comprise a substantially pure silicone.
7. The apparatus of claim 1 , further comprising power means configured to apply a power to the light emitting device to emit light.
8. The apparatus of claim 7 , wherein the power means is further configured to test light emitting devices at pulsed condition.
9. A system for dispensing a phosphor composition onto a light emitting device, comprising:
a light sensor configured to detect a characteristic of light emitted from the light emitting device;
a plurality of phosphor dispensers, each configured to dispense a respective color phosphor onto a surface of the light emitting device; and
a controller configured to adjust relative amounts of the color phosphors during dispensation to reduce a difference between the detected characteristic of the light and a desired characteristic of the light and determining whether the detected characteristic of light is within a predetermined range for the desired characteristic of the light,
wherein the controller is further configured to iteratively: control the phosphor dispensers dispense one or more of the phosphors, detect the characteristic of the light, and adjusts the relative amounts of the color phosphor while the detected characteristic of the light emitted from the light emitting device is outside of the predetermined range for the desired characteristic of the light, and
wherein the controller is further configured to control the phosphor dispensers to dispense the one or more of the phosphors until one of a predetermined volume or a predetermined weight of the phosphor composition has been dispensed while the detected characteristic of the light is within the predetermined range.
10. The system of claim 9 , wherein the phosphor dispensers are further configured to adjust a ratio of the respective color phosphors to dynamically reduce a difference between the detected characteristic of the light and a desired characteristic of the light while dispensing the respective portions of the phosphor composition.
11. The system of claim 10 , wherein the phosphor dispensers are further configured to dynamically adjust a dispensing time and/or speed to reduce the difference between the detected characteristic of the light and the desired characteristic of the light while dispensing the respective portions of the phosphor composition.
12. The system of claim 9 , further comprising a silicone dispenser for dispensing substantially pure silicone onto the surface of the light emitting device.