Other Parts Discussed in Thread: DLPC4430EVM, , DLP800RE, DLPC4430
Tool/software:
Hello we are using the DLP800REEVM with the DLPC4430EVM for micromirror control. We are illuminating the DMD with a stable QTH lamp in the normal direction. Using the GUI and HDMI connection we can produce a good all micromirror OFF state. We see this visually as all of the light only going in the OFF direction. When however we display a white screen with HDMI or use the test pattern white background, all of the light is not going into the ON direction. We understand that the pond of mirrors are only addressable in the OFF state so we are only illuminating a central circle of the DMD(we use an iris). We have 2 theories of what might be going on:
1. The white in the GUI white background is not (255,255,255) so the micromirrors are setting the brightest white value which is not with all of the micromirrors all ON for the full cycle.
2. The DLP processing assumes an RGB illumination so there is an unbounded state or dithering even with full white. This would cause a portion of the micromirrors to flip to the OFF state which would cause an imbalance.
Let us know if one of these is more right. We would like to make a contrast measurement so it is essential to have all micromirrors in the ON state. Going forward is there a way through software where we could feed the electronics a bitmap of the micromirror positions(0 or 1) so we can make an all ON measurement or half ON, half OFF.
Thanks,
Christian
