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DLP Projector Design - Refresh Rates And Autoscan

Tom Sorbel
Prodigy 20 points

To Whom It May Concern,

I have a technical question about TI's DLP projector technology and the "Autoscan" function.  I have a Sharp XV-Z20000 DLP projector (top of the line several years ago).  The specs say it has a vertical freq. range of 43-100hz.  Does this mean if I feed the input with a 48hz, 50hz,60hz, 98hz, etc., vert rate, the Autoscan feature will allow the projector to refresh (output) at those same rates?  Someone told me that the projector display only refreshes at 50 or 60 hz (converts incoming vert rates back to 50 or 60hz).  But I would like to send it 48 hz, and display at 48 hz (vert. rate) (double of native 24p bluray output).

So, is the Texas Instruments DLP "Autoscan" specs designed to output (refresh display) at variable rates (not just 50 or 60hz), in DLP designed projectors?

Thanks, in advance of your answer!

Tom

 

  • 0
    TI__Mastermind 30875 points

    Hi Tom,

    Welcome to DLP & MEMS forum.

    The DLPs can display at variable rate but it depends on whether the manufacturer used this option or not. There are other  things that goes into projector apart from DLP display electronics. So, combination of these will determine how the projector is designed and which method it is using for display.

    In your case, a simple experiment will let you know the display refresh rate. The experimental setup will be , input video with alternating "black" and "white" frames at known frame rate. Now, put a photo detector and observe for a light variation by connecting output of photodector to oscilloscope. There will be alternating full-off and full-on light variations when seen on oscilloscope, the duration of either region will tell the display frame rate.

    Typical datapath looks something like this -

    External Video Source -> Front-End-Processing(Manufacturer Design) -> DLP Display System (TI).

    The Front-End-Processing block does the frame rate conversion and feeds to DLP system at fixed rate. This is how this particular projector is designed. You can get in touch with Sharp see if they are willing to provide this information.

    If you are doing scientific experiments we suggest you to have look at www.ti.com/mems and use the kits listed.

    Regards,

    Sanjeev

     

  • 0 in reply to Sanjeev
    Prodigy 20 points

    Dear Sanjeev,

    Thank you for your helpful response - I really appreciate it!.  I will look into this issue further from Sharp.

    Regards!

    Tom