Display system for higher grayscale with a varying light source

1. A display system comprising at least one Spatial Light Modulator (SLM) and at least one variable light source and at least one control unit controlling said SLM and said light source wherein:

1) said control unit applies multiple-bits image data to control a plurality of micromirrors of the SLM to modulate an illumination light wherein a least significant bit (LSB) of the multiple-bits image data defining a minimum controllable time period for each of the micromirrors of the SLM during a display frame period represented by the multiple-bits image data;

2) said control unit controls the micromirror to operate at least twice in the display frame period; and

3) said control unit also simultaneously controls said light source to project different light intensities of the illumination light to the SLM during said minimum controllable time periods to increase a controllable gray scale of the display system without reducing a significant amount of image brightness.

2. The display system according to claim 1 , wherein:

said control unit controls the light source to project the illumination light with at least two different light intensities during said minimum controllable time periods.

3. The display system according to claim 1 , wherein

said control unit controls the light source to project the illumination light in light pulses having different controllable time widths during said minimum controllable time periods.

4. The display system according to claim 1 , wherein

said control unit controls a timing of the light source in projecting the illumination light during said minimum controllable time periods.

5. The display system according to claim 1 , wherein:

said control unit controls the waveform of the light source in projecting the illumination light during said minimum controllable time periods.

6. The display system according to claim 1 , wherein:

said control unit controls the light source to project the illumination light in light pulses having different controllable numbers of the light pulses during said minimum controllable time periods.

7. The display system according to claim 1 , wherein:

said control unit controls the light source to project the illumination light in light pulses having a controllable frequency during said minimum controllable time periods.

8. A display system comprising at least one Spatial Light Modulator (SLM) and at least one variable light source for projecting an illumination light to the SLM, and at least one control unit controlling said SLM and said light source wherein:

1) said control unit controls said SLM by applying multiple-bits image data wherein each bit of the multiple-bits image data defining a controllable modulation period wherein the control unit applies at least twice a designated bit of the image data to operate the SLM to modulate the illumination light during two designated controllable modulation periods in a frame period represented by the multiple-bits image data; and

2) said control unit simultaneously controls said light source during said two designated controllable modulation periods to project the illumination light with different light characteristics to said SLM.

9. The display system according to claim 8 , wherein:

said control unit controls the light source to project the illumination light with at least two different light intensities during said two designated controllable modulation periods.

10. The display system according to claim 8 , wherein:

said control unit controls the light source to project the illumination light in light pulses having different controllable time widths during said two designated controllable modulation periods.

11. The display system according to claim 8 , wherein:

said control unit controls a timing of the light source in projecting the illumination light with different timings during said two designated controllable modulation periods.

12. The display system according to claim 8 , wherein:

said control unit controls the waveform of the light source in projecting the illumination light with different waveforms during said two designated controllable modulation periods.

13. The display system according to claim 8 , wherein:

said control unit controls the light source to project the illumination light in light pulses having two different controllable numbers of the light pulses during said two designated controllable modulation periods.

14. The display system according to claim 8 , wherein:

said control unit controls the light source to project the illumination light in light pulses having two different controllable frequencies during said two designated controllable modulation periods.