Calibrated LED light module

1. A light source comprising:

a substrate;

a plurality of dies mounted on said substrate said dies being encapsulated in a transparent cap comprising a layer of material that extends around all of said dies, each die comprising an LED emitting light having a different spectrum from said other LEDs, each LED generating light of an avenge intensity that is determined by a drive signal connected to that LED;

a sensor that generates a plurality of signals, each signal being characterized by a sensor value that is indicative of the intensity of light emitted by a corresponding one of said LEDs and independent of the intensity of light emitted by any other LED in said light source, said sensor comprising at least one photodetector that is encapsulated in said layer of material; and

a controller that generates said drive signals and stores a current target value for each LED, wherein

said light source operates in a calibration phase and an operation phase, wherein during said operation phase said controller generates said drive signals for each of said LEDs such that said sensor value for that LED matches said stored current target value for that LED, and wherein during said calibration phase, said controller stores said current target values.

2. The light source of claim 1 wherein said controller stores the current values of said sensor values as said current target values in response to an external control signal being coupled to said controller during said calibration phase.

3. The light source of claim 1 wherein said sensor is mounted on said substrate.

4. A light source comprising:

a substrate;

a plurality of LEDs mounted on said substrate and encapsulated in a transparent cap, each LED emitting light having a different spectrum from said other LEDs, each LED generating light of an average intensity that is determined by a drive signal connected to that LED;

a sensor that generates a plurality of signals, each signal being characterized by a sensor value that is indicative of the intensity of light emitted by a corresponding one of said LEDs and independent of the intensity of light emitted by any other LED in said light source, said sensor comprising at least one photodetector that is encapsulated in said transparent cap; and

a controller that generates said drive signals and stores a current target value for each LED, wherein

said light source operates in a calibration phase and an operation phase, wherein during said operation phase said controller generates said drive signals for each of said LEDs such that said sensor value for that LED matches said stored current target value for that LED, and wherein during said calibration phase, said controller stores said current target values;

wherein said sensor measures light leaving a sidewall of a die that includes one of said LEDs.

5. The light source of claim 1 wherein said sensor measures light reflected from a boundary of said transparent cap.

6. The light source of claim 1 wherein said transparent cap comprises a lens.

7. The light source of claim 1 wherein said controller stores a plurality of sets of target values, and wherein said controller selects one of said sets of target values for said current target value in response to an external signal being connected thereto.

8. A method for fabricating a light source, said method comprising:

attaching a plurality of dies to a substrate, each die comprising an LED emitting light having a different spectrum from said other LEDs, each LED generating light of an average intensity that is determined by a drive signal connected to that LED; and

providing a sensor that generates a plurality of signals, each signal being characterized by a sensor value that is indicative of the intensity of light emitted by a corresponding one of said LEDs and independent of the intensity of light emitted by any other LED in said light source;

encapsulating said LEDs and said sensor in a transparent cap comprising a layer of material that extends around all of said dies and said sensor;

attaching a controller to said substrate, said controller being connected to said LEDs and said sensor, said controller generating said drive signals and storing a current target value for each LED-wherein said light source operates in a calibration phase and an operation phase, wherein during said operation phase said controller generates said drive signals for each of said LEDs such that said sensor value for that LED matches said stored current target value for that LED, and wherein during said calibration phase, said controller stores said current target values;

causing said LEDs to generate light corresponding to a predetermined color point during said operation phase;

causing said controller to store said sensor values as said target values when said LEDs generate light of said predetermined color point during said calibration phase.

9. The method of claim 8 wherein said LEDs are caused to generate light corresponding to said predetermined color point by measuring light from said light source in a calibrated light detector separate from said light source and varying said drive signals until said calibrated light detector indicates that said light generated by said LEDs matches said predetermined color point to within a predetermined accuracy.

10. The method of claim 9 wherein said calibrated light detector receives light from all of said LEDs during said measurement.