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NIR DMD Chipset off wavlength range and damage threshold.

Santosh Kumar82
Prodigy 140 points
Other Parts Discussed in Thread: DLP2010NIR, DLP4500NIR

Can I use NIR chips for Red wavelenghts, I have a requirement to use 600 - 1100 nm?

Also what is the laser damage threshold of NIR chipsets?

  • 0
    TI__Guru 54685 points

    Hello Santosh,

    The data sheet specifications are the terms of warranty for our devices, so operating below 700 nm is outside the specifications.

    As long as you are willing to accept the risk, it should still operate, but near 600 the window transmission will be reduced. [See Wavelength Transmittance Considerations for DLP DMD Windows (Rev. C) for details].

    The second question is not as easy to answer.  The following paper was written before the pixel architecture used in the DLP2010NIR.  See Laser Power Handling for DMDs. The general principles still apply but you will need to test your particular setup.

    For your laser operation, what are the maximum parameters for the laser you expect.

    Please let me know if I can help you further.


    Fizix

  • 0 in reply to Fizix
    Prodigy 140 points
    Thanks for the answer.
    I think i can still use 600nm, if I am willing to the losses, that i can calculate and compensate.
    Also I understand that , for LDT estimation of the mirror in NIR range we have to normalize 25W/cm2 w.r.t absorption spectra.

    I have few further queries,

    As mirrors are Al coated, NIR absorption is high, can we use efficient cooling system and increase the Laser damage threshold?

    Is there any temperature sensor inbuit into the DMD so that we can track or any suitable best location we can add RTD to track temperature so that we can efficiently cool it?

    Typically i want to use 500mW laser power, also i would like to know what maximum power DMD can handle, from document LDT in VIS range is 25W/cm2 and I scale down to 80% in NIR range, it becomes 20W/cm2, with active area 0.1 cm2, maximum limit is 2W, am I right?

    Regards,
    Santosh
  • 0 in reply to Santosh Kumar82
    TI__Guru 54685 points

    Hello Santosh,

    normalizing to 25 W/cm2 is important, however the specification has been changed to a thermal limitation so that customers will focus on the fact that the array temperature is the critical specification.  An good thermal solution is required.

    Therefore, using an efficient cooling solution will give more Laser Power handling.

    Although there is no temperature sensor, we typically make a very small groove in the face of the thermal cooling interface of the heatsink and epoxy a thermocouple there to measure the temperature at the back of the package.

    Finally, are you talking about the DLP2010NIR or the DLP4500NIR (for the 4500 there are two packages, which are you looking at?)

    Regarding

  • 0 in reply to Fizix
    Prodigy 140 points
    Thanks for the reply.
    I want a cost effective solution, so DLP2010NIR.
    Regards,
    Santosh
  • 0 in reply to Santosh Kumar82
    TI__Guru 54685 points

    Hello Santosh,

    Please be aware that the DLP2010NIR does not have a thermal interface area, so the power handing will be relatively low.