Method and apparatus for sequencing light emitting devices in projection systems

1. An apparatus comprising:

an illumination source including a number of light emitting devices each emitting incident light of a different constituent color, and having a duty ratio for a frame period approximately inversely proportional to the number of light emitting devices; and

a light valve, optically coupled to the illumination source, to modulate the incident light into image bearing light for the frame period.

2. The apparatus of claim 1 , wherein the number of light emitting devices comprise one or more light emitting diodes.

3. The apparatus of claim 1 , wherein the number of light emitting devices comprise

a first light emitting device to emit light of a first color;

a second light emitting device to emit light of a second color;

a third light emitting device to emit light of a third color; and

each of the first, second, and third light emitting devices to emit light as a plurality of pulses for the frame period.

4. The apparatus of claim 3 , wherein each of the first, second and third light emitting devices emit light of a selected one of a group consisting of red color, a blue color, and a green color.

5. The apparatus of claim 3 , wherein the frame period comprises at least two subframe periods, each of the at least two subframe periods to include at least one pulse from each of the first, second and third light emitting devices.

6. The apparatus of claim 5 , wherein only one of the first, second, and third light emitting devices emit light at one time.

7. The apparatus of claim 1 , wherein at least one of the number of light emitting devices, having a rated current, is pulsed at a current approximately proportional to the number of light emitting devices times the rated current.

8. The apparatus of claim 1 , further comprising

a controller, coupled to the light valve, adapted to receive data representing an image frame and to synchronize operation of the light valve with the incident light according to the data for the frame period.

9. An apparatus comprising:

a light valve to modulate light over a frame period; and

an illumination source including a light emitting device to provide light to the light valve as a plurality of pulses over the frame period, a first pulse of the plurality of pulses configured to have a pulse duration based at least in part on a reduction in light output over a course of the pulse duration.

10. The apparatus of claim 9 , wherein the light emitting device is a first light emitting device to emit light of a first color and the illumination source further comprises:

a second light emitting device to emit light of a second color;

a third light emitting device to emit light of a third color; and

each of the first, second, and third light emitting devices to emit light as a plurality of pulses for the frame period.

11. The apparatus of claim 9 , wherein the light emitting device has a duty ratio for the frame period and a rated current, and the first pulse of the plurality of pulses has a pulse amplitude based at least in part on the duty ratio and the rated current.

12. The apparatus of claim 11 , wherein at least the first pulse of the plurality of pulses is pulsed with a current over the rated current, and the average current applied to the light emitting device over the frame period is approximately equal to or less than the rated current.

13. A method comprising:

presenting data representing an image frame to a light valve to facilitate the modulation of light over a frame period; and

illuminating the light valve with a plurality of pulses from a light emitting device over the frame period, a first pulse of the plurality of pulses configured to have a pulse duration based at least in part on a reduction in light output over a course of the pulse duration.

14. The method of claim 13 , wherein the light emitting device is a first light emitting device providing a first plurality of pulses and said illuminating of the light valve further comprises:

providing a second plurality of pulses with a second light emitting device; and

providing a third plurality of pulses with a third light emitting device.

15. The method of claim 14 , wherein at least one pulse from each of the first, second, and third plurality of pulses have similar durations and/or amplitudes.

16. The method of claim 15 , wherein said illuminating the light valve with a plurality of pulses further comprises illuminating the light valve with a plurality of pulses having pulse values corresponding to a least significant bit of the data representing the image frame.

17. An apparatus comprising:

an illumination source including a plurality of light emitting devices to emit incident light as a plurality of pulses of a number of colors, at least one of the plurality of light emitting devices having a duty ratio for a frame period approximately inversely proportional to the number of colors; and

a light valve, optically coupled to the illumination source, to modulate the incident light over the frame period.

18. An apparatus of claim 17 , wherein the at least one of the plurality of light emitting devices, having a rated current, is pulsed at a current approximately proportional to the number of colors times the rated current.