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DLP650LNIR: Is it possible to use visible light DMD without window for NIR range?

Peng Du
Prodigy 35 points
Part Number: DLP650LNIR

Hello,

My research group is looking forward to buying several NIR DMD devices with binary pattern rate as high as possible. Since our group work in a dust-free lab, is it feasible for us to buy a DMD for visible light which has a higher binary pattern rate, and uninstall the window? My understanding here is the DMDs for different wavelength range are using the same aluminum mirror, the only optical difference here is the window glass. So it should be possible to use the visible DMD without window for NIR wavelength. Is there any better solution?

Thank you in advance.

Best regards,

Luka

  • 0
    TI__Expert 4530 points

    Hi Luka,

    Tampering with DMD will void the warranty. Let me check with our design experts for any solution to help you.

    -ykc

  • 0 in reply to ykc
    TI__Expert 4530 points
    Hi Luka,

    I checked with expert, it is not recommended to take the window off the DMD as this could certainly cause reliability issues even in a clean room environment.

    What specific wavelength and incident illumination power conditions are you going to use?
    You can calculate the DMD efficiency degradation from NIR illumination of a visible DMD (with window) by looking at Figure 1 in the Wavelength Transmittance Considerations for DLP® DMD Window document on ti.com. For example, the document shows the visible window transmittance for 850 nm is approximately 90% instead of about 99% in the visible region. Therefore, the efficiency losses due to the window at 850 nm will be approximately 100 – (90% x 90%) = 20% losses just for the window. It gets worse as one moves upwards in wavelength.

    www.ti.com/.../dlpa031d.pdf
  • 0 in reply to ykc
    Prodigy 35 points

    Thank you very much for your detailed answer. The illumination we want to use is a 880 nm laser, for which a gold/silver coating mirror would be the best choice. It seems the aluminum mirror is the only option for DMD, so as to reduce the power loss due to the reflectivity, we want to uninstall the mirror. The other reason is we want the pattern rate to be as fast as possible, and the visible light DMD chip can have a higher pattern rate. We are aware of the fact that tampering the mirror will void the warranty, but we still want to discuss the possibility. I wonder if you could provide us with the contact information of a DMD expert, so that my professor can have a direct in-depth communication to determine which product we should buy.

    Looking forward to your reply!

    Best regards,

    Luka

  • 0 in reply to Peng Du
    TI__Guru 54645 points

    Hello Peng,

    TI does not support removal of the window.  The cavity has proprietary material inside that ensures continued operation of the micro-mirrors.

    Please be aware of the new NIR offering that has higher pattern rates than some of the previous offerings:

    http://www.ti.com/tool/dlplcr65nevm 

    You would also need to purchase the controller board for this DMD EVM:

    http://www.ti.com/tool/dlplcrc410evm

    This will help with the efficiency issue and have improved speed.

    NOTE:  The GUI is a good place to start, but eventually you would need to write VHDL for the APPS_FPGA to create your own high speed custom solution.

    Fizix

  • 0 in reply to Fizix
    Prodigy 35 points

    Dear Fizix,

    Thanks for your reply! 

    I am aware of the DLP650LNIR provides a binary pattern rate up to 12,500 kHz, but we want to have a binary pattern rate around 20 kHz to 30 kHz, which is only achievable by the visible light DMD. This is the reason why we consider the possibility to use a visible light DMD. Our illumination is a 880 nm laser, for which the gold/silver mirror coating is the best choice. But DMD chips use aluminum mirror, so removal of the window would reduce the light loss. I wonder if TI has plan to manufacture higher-speed DMD chips or could you provide the customized combination with NIR window on a visible light DMD. And I would appreciate it very much, if you could provide me with  your contact information for further communication. 

    Looking forward to your reply!

    Best regards

  • 0 in reply to Peng Du
    TI__Expert 4530 points
    Please contact

    Carey Ritchey

    e2e.ti.com/.../1993915

    Texas Instruments

    Industrial Business Development Manager

    DLP® Enterprise & Cinema Display

    www.ti.com/dlp

    -ykc