FLASH FORMATIONS: a brief conversation with Texas Instruments
It sounds easy enough — use four flashes of 1920 x 1080 to make the UHD resolution of 3840x 2160. The numbers are easy. But the geometry is less obvious. After significant debate between author and Editor over the possible implementations, we came up with three potential answers.
The first is the simplest. The DMD could deliver 1920 x 1080 to four entirely separate quarters of the screen. But this would require moving the entire DMD around significant angles, and might also create borders or potential time-smearing as the separate sections appeared. So unlikely.
Second: the pixels on the DMDs might occupy only a quarter of the micromirror area, so they can be shifted half a mirror in each direction to deliver four adjacent pixels. But this would make the pixels tiny, potentially affecting brightness.
Or third, full-size pixels (filling most of each micromirror) are delivered to four separate positions that overlap. This would seem to require image processing of each frame prior to delivery (to calculate and negate the effects of overlapping), but then this geometry is the only way to make sense of previous DMDs which doubled 2716 x 1528 to make 4K.
We contacted Texas Instruments, creators of the miraculous DMD chips. “The DLP470 TE and DLP470TP4K UHD chip sets display four pixels on the screen per micro mirror ”, they said, and when we asked for further clarification, they
replied that: “
array of micro mirrors, which switch on the order of The DLP470 TE uses a 1920x 1080 microseconds, to create four distinct address able pixels on the screen during every frame to deliver full 4 K UH D resolution ... The complete set of pixels are over sampled and processed by unique TI image processing algorithms leading to a crisp, colorful& detailed full 8- megapixel 4 K UH D display .”
Can you confirm that the addressable pixel spaces overlap each other? Is the image processing required to predict the overlap effects?
“I appreciate your interest in how our newest 4 K UH D technology works ,” replied our correspondent ,“butt he DLP image processing algorithms are proprietary and I’ m afraid I can’ t go into anymore detail .”
But from that, together with a diagram from Ben Q, we reckon it’s option 3 — oversampling and pre-processing, then 240Hz flashing to four clockwise-adjacent positions, with overlaps.