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DLP7000: Usable spectral range of DLP

Damien Etienne36
Prodigy 30 points
Part Number: DLP7000


DLP7000 spectral range is given 400 to 700 (and other ranges for specific devices).

My application needs to process light in a range from 300 to 1200nm.

Given the cover glass specs and the aluminium reflectivity specs, this should be doable, however there are no spectral response data of the DLP units.

My application does not require high power, and the light could be pulsed at low duty to reduce thermals. Even a reflectivity of 30% would suffice and does not require to be linear over the range.

One solution also can be to use several units but that would make design significantly more complex.

Anyone has experience, data or comments, suggestion on this matter?

  • 0
    TI__Expert 4530 points
    Hi Damien,

    DMD is characterised for 400-700nm. Using beyond these limits will void the device warranty.

    -ykc
  • 0 in reply to ykc
    TI__Guru 54705 points

    Hello Damien,

    I would add that the window has an AR coating.  Without it there would be too much reflection to be useful for many applications in the visible range.  Particularly for projection systems, which this chip was primarily designed for.  

    A UV optimized window device is also available, but there are other considerations for limiting the wavelength for that device to 363 nm and above.

    What are you attempting to design?

    Fizix

  • 0 in reply to Fizix
    Prodigy 30 points

    A monochromator, range from 300 to 1200nm. Perhaps DLP wouldn't be a good solution in that application.

  • 0 in reply to Damien Etienne36
    TI__Guru 54705 points

    Hello again Damien,

    Without AR coatings, it would be hard to build a monochromator with a DMD because of the unwanted reflections off of the window surfaces.  Further, it is extremely difficult to make and AR coating that spans that large of a wavelength range.  This is why many monochromators use a first surface grating.

    Fizix

  • 0 in reply to Fizix
    Prodigy 30 points

    Given that it's very difficult to build a DMD with a large WL AR coating anyway, how about without AR Coating.

    Unwanted reflections can be dealt otherwise (further optics, software corrections, lock-in amplifier).

    My application doesn't need to have a high wavelength purity as it's to measure the response of silicon junction.

    Can AR coating be removed (chemically, mechanically) from commercial DMD in order to increase the spectral range?

    The implementation would basically be a light source, a grating and a DMD and using the lock-in amplifier method, which should cancel any stray light.

    Thanks for your feedback. 

  • 0 in reply to Damien Etienne36
    TI__Guru 54705 points

    Damien,

    Be aware that all DMD's have an AR coating for some given wavelength range.  That coating is on both the outside AND the inside.  

    We have had a few customers that have had the outer coating mechanically removed (with some difficulty & expense) by a third party.  

    I am not sure how the lock-in amplifier will help with unwanted reflections of the chopped light.

    Let us know if you come up with anything.

    Best regards,

    Fizix