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Pixels clock with video mode on dlplcr6500

Hello,

Since i had this problem: (https://e2e.ti.com/support/dlp__mems_micro-electro-mechanical_systems/f/94/t/415270), which has not been fixed yet, i can not use my dlplcr6500 in any form of pattern mode. I am trying, while waiting for a fix, to use the device in video mode as an external screen through the displayport connector. My new problem is that i need the device to project binary patterns, with some pixels "permanently" on and some off.
I thought that would be easy, by just setting the pixels to rgb (255,255,255) for "on" and to rgb (0,0,0) for "off".
However, i can see that, while the "off" pixels seems to be completely off, the "on" pixels keep flickering a little bit. If i use short exposures i can see the image "striped" along the horizontal axis. This happens with the hdmi port, displayport, and even with the internal pattern named "Solid field". I can not recall this happening in pattern mode.

You can find attached an image of the dmd screen, acquired with 1 ms exposure time, while using it in a microscope with the "solid field" internal pattern on it. looking at it live, the stripes maintain their width and seem to move randomly across the field of view.





Is there a reason for this? Possibly an easy fix? I can still use it, but having the stripes on all images is definitely annoying.

Thanks for your help

Paolo

  • Hi Paolo,

    I believe what you are seeing here is the micromirror reset. Video mode (unless you are operating in dual pixel mode), operates at 60 Hz. This means that a frame is exposed for 16ms. You might want to try lengthening the exposure of your camera closer to that value and seeing if that improves the effect you are seeing.

    Also, we are still working on your previous question (referenced above). I will be in contact with you and I thank you for your patience while we work through the issues you are seeing in regards to the flash devices.

    Best regards,
    Trevor