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DLPC900: DLP lightcrafter 9000EVM

Peter678
Prodigy 190 points
Part Number: DLPC900
Other Parts Discussed in Thread: DLP9000, DLP6500FYE

Hi,

I want to konw the mirror flickering problem about DLP lightcrafter 9000EVM.When we upload a static pattern, the mirror won’t stay in one state (on/off) for too long,preventing mirrors from getting stuck. So the mirror will be termed in ‘flat’ state every cycle by the manufacturers,which will cause the reflecting power decay suddenly.You can find the detailed information from the article ‘suppression kHz-frequency switching noise in the digital micro-mirror devices’. So I want to konw if the DLP lightcrafter 9000EVM have the same problem?If it has,what’s the cycle time?Dose it exist in all dlp series from TI.

Best regards,

  • 0
    TI__Prodigy 675 points

    Hello, Peter.  If I understand your question correctly, you are asking if the DLP LigthCrafter 9000 has any mirror cycling features built-in to prevent stuck pixels for 100% duty cycle (always on) patterns.  There is not such a bult-in feature.  In a final system implementation, it is always a best practice to cycle the mirrors at 50/50 duty cycle when the application  can tolerate it (downtime) rather than have them always on or always off to avoid hinge memory for the MEMS structure.  However, it is up to the final system designer/integrator to make the decisions about when and how often such mirror exercising should be done.  You can read more about this topic in the DLP9000 datasheet online in Section 9.7:

  • 0 in reply to Raecine Meza
    Prodigy 190 points
    Hi Raecine Meza,
    Thank you for your reply.If I buy DLP® LightCrafter™ 9000 Evaluation Module from Texas Instrument,is it possible for me to make the dmd run in the 100% duty cycle when I upload 1bit-depth pattern? Is it complex?
    Best Regards,
  • 0 in reply to Peter678
    TI__Prodigy 675 points

    Yes.  The user guide for the EVM describes how to connect the EVM to your computer and shows screenshots for the GUI software to generate a pattern.  You can check it out here: 

  • 0 in reply to Raecine Meza
    Prodigy 190 points

      Thank you for you reply,but I still have some questions.In order not to make mistakes,now I describe my experiment. We illuminate  laser on the surface of DMD ,by controlling the on and off state of the micromirrors we can get some special and static pattern (1bit-depth patterns displayed on the DMD are completely static and avoid fluctuations due to intensity modulation ,that’s very important).

       However,if the mirrors remain in the on- or off -state too long,the mirrors can either get stuck on the landing pads due to surface adhesion or deform due to the applied stress. For these reasons, DMD manufacturers usually implement a switching cycle which applies the MCP(mirror clocking pulse) every clock cycle, even if the pattern has not been updated.This is the mirrors flickering problem I’m describing.

       The figure shows the measured power vs time with all mirrors on, and their test device is DLP6500FYE implemented in the  Lightcrafter EVM 6500 kit  from Texas Instruments. The result is from the article--------’suppression kHz-frequency switching noise in the digital micro-mirror devices’. Besides,they solve the problem in the hardware level. They interrupt the mirror clocking pulse (MCP) between the sequencer chip and the actual DMD(by pulling the MCP to ground), effectively freezing the DMD mirrors in their present position. To load the next pattern from the sequencer chip to the DMD, the MCP is restored for a short time. 

       I have read the user’ guides you give me ,if I choose the one of the three pattern modes(pre-stored pattern mode, video pattern mode, pattern on-the -fly mode),and upload one 1- bit-depth pattern,and set the exposure time to 50s. Does it mean that in the 50 seconds all mirrors won’t  flicker like the result of test where reflecting power decays suddenly every 105 microseconds? Is DLP® LightCrafter™ 9000 Evaluation Module different from Lightcrafter 6500 EVM regarding this problem?

    Best Regards,

  • 0 in reply to Peter678
    TI__Prodigy 675 points
    Let's separate the evaluation phase of a project and a final system implementation phase. The LightCrafter 9000 is indeed just an evaluation module that you can give any pattern you like and test out the device's capabilities. We do not add extra mirror cycling to any evaluation module.

    When you design your actual system, then it is a good idea to cycle the mirrors now and then as your application allows. Only a final system implementation where the system designer deliberately programs the device to do so will have the "flickering" you describe. There is even a special function call you can use to exercise the mirrors in this way. But, again, TI does not force the EVM or any device to do that. It is up to the system designer to determine when and how to do this. The DLP chip only does what the programmer tells it to do.
  • 0 in reply to Raecine Meza
    Prodigy 190 points
    so if the EVM is directly from Texas Instrument (not from DLi ,Vialux or other companies which is the designer you mention),and I don't cycle the mirrors, just do as the users' guide to upload the pattern, the flicker won't happen.Am I right?