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Hello, I am currently using the DLP4710EVM-LC to evaluate the DLPC3479/DLP4710 for an upcoming product, and I have a question on how the mirrors are modulated during the last 3 or 4 bits in either 7 or 8 bit internal pattern mode: is it possible to reduce the periods of time the mirrors are off in between these bit exposures?
Here is a scope capture of a photodiode's output when looking at an all-white 7-bit image being projected. Negative values here indicate detected light. The red arrows point to the "inter-bit dark periods" I'm asking about.
A key aspect of my use-case is to project a lot of light in a fixed amount of time -- we are working on a higher current LED drive, but the mirrors being off for so long reduces the amount of light we can project in a given timeframe by about 25%: in the image above, each off period is ~142 us, and the total exposure time projecting is 1,644 ms. This results in ~26% of the display time not having light projected (not including pre or post dark times or pattern set load times).
Is that inter-bit dark period configurable, or is there another tactic for increasing the percentage of time the DLP is projecting during an exposure?
Thanks!
-Matt
Hi Vivek-
This capture is for one complete frame, yes. In the image I provided above, it is projecting an all-white 8-bit 1-D image with an exposure time of 1,677 ms. Only the blue LED is used. This capture was taken using the EVM's GUI tool to continuously project images. Here is a capture showing several frames as well as the PATTERN_READY and TRIGGER_OUT_2 signals:
This same inter-bit dark time is present with 8-bit images, even at the maximum allowed exposure time of 4,168 ms:
Let me know if there's more information needed -- I can send Saleae captures as well if that's more useful.
Thanks!
-Matt
