3D DLP-Link syncs to black gaps instead of white flashes? Confused.
I always assumed that 3D DLP Link works by a single very short white flash after left and right image have been shown (L, R, flash, L, R, flash, ...). The glasses would distinguish between L/R by measuring the time between flashes and switch once half the time between them has passed.
Now I happen to record my BenQ TH682ST at 960fps and I don't see any evidence of a white flash at all. It turns black for ~2ms after each frame though. Left (Cyan, Blue, Green, Red, Yellow), Black, Right (Cyan, Blue, Green, Red, Yellow), Black.
This would correspond to the 60° white segment of the color wheel at 120 Hz. (1000ms/120Hz/360° * 60° = 1.4ms). So apparently the DMDs switch to black during the white segment.
But this does not explain how the glasses know which frame is left and which is right. It also should make sync harder when the content is primarily dark.
So what am I missing here? Is the white segment dark because within it there is actually a white flash being shown but it is so short that I can't capture it at 960fps? How short is it?
Is there any technical documentation / specs / paper on the internet where I could verify this?
Thanks a lot for your help in advance!