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DLP801RE: uneven illumination

Christian Robles
Prodigy 140 points
Part Number: DLP801RE

Tool/software:

What is the long term effect of uneven illumination on the DMD? For our application, we are interested in illuminating 6 W of power over the center of the DMD. If this is over 10.6mm2 this would give a power density of around 56 W/cm2 which exceeds the 40 W/cm2 listed in the data sheet. Also if we were able to get this 6W of power over .15 cm2, thereby achieving the 40 W/cm2 would this damage a portion of the DMD over time. The illumination would be all day and none at night.

Thanks

  • 0
    TI__Guru 54285 points

    Hello Christian,

    It is critically important that a sufficient thermal solution be provided to keep the array temperature.  I calculate 56.6 W/cm^2 in line with your calculation.  

    You are correct that at 15 mm^2 this would give 40 W/cm^2 which is at the data sheet spec limit.  I do not know if we have sufficient data to predict the long term effect of operating this way.  This presents a fairly large gradient at the edge of the illumination area.

    What is driving the need for such a small illumination area?  The active area is about 186 mm^2.

    Fizix

  • 0 in reply to Fizix
    Prodigy 140 points

    We are planning on imaging a light source that is located far away(astronomical). The focal length then drives the size of the image and a larger focal length which would produce a larger image on the DMD would be more optically challenging for our design requirements. For design purposes, what thermal properties are expected from an illumination that is centered on the DMD and is a finite size? Thinking about an R value or equivalent so we could estimate how different illumination areas would have on the temperature of the DMD. I found the application note "Digital Micromirror Device Thermal Considerations Including Pulsed Optical Sources" and I would like to go through this with more specific values to drive design choices while not "burning up" the DMD over long term usage.

    -Christian

  • 0 in reply to Christian Robles
    TI__Guru 54285 points

    Dear Christian,

    After you have a chance to go through the App Note that you mentioned, let me know if you have further questions.  For now I am going to mark this as "TI Thinks Resolved".  You can re-open it or post a new question.

    Fizix