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DMD mirror position

Admir Asanoski
Prodigy 115 points
Other Parts Discussed in Thread: DLP5500

Hi all,

i've got a question about the mirror positions of a DMD-chip.

It has an on and an off position for example +12° and -12°.

Is it possible to operate with 0° or must the mirror be mechanically blocked??

 

Thanks you in advance!

 

Best regards,

Admir

  • 0
    TI__Expert 6370 points
    Hi Admir,

    The DMD micromirrors are only able to be in one of their two latched positions, +12° and -12°. When power is removed from the DMD, the micromirrors will returned to a "parked" position at roughly 0° (which is undefined and unspecified), but it is not possible to achieve that position while the DMD is operational.
    I hope this answers your question, let me know if you have any other questions!

    Best regards,
    Trevor
  • 0 in reply to Trevor Dowd
    Prodigy 115 points

    Hi Trevor,

    thanks for the fast and helpful answer!

    I have another question. I want illuminate the DMD-chip and then reduce with projection lenses to improve the resolution.

    The wavelenght is broadband (about 300-450 nm) or a monochromatic wavelenght about 436nm.

    Which source to illuminate the DMD-Chip you would recommend? (LED, laser diode,...)?

    Are there special requirements for the light for example monochromatic or polychromatic, collimated or divergent to operate with a DMD chip?

    What intensities (mW/cm^2) are allowed on a DMD-chip? If i have a source with an intensity about 100mW/cm^2 did i have the same intensity after the chip or are there any losses?

     

    Thanky you in advance!!

    Admir

  • 0 in reply to Admir Asanoski
    TI__Expert 6370 points

    Hi Admir,

    Most DMDs have an operating range of 420 - 700 nm (or 400 - 700 nm). You can sort through the available products by illumination wavelength range on this page: http://www.ti.com/lsds/ti/dlp/advanced-light-control/products.page

    After selecting the DMD that best suits your application (resolution, speed, etc.), you can check out the individual datasheets for maximum (W/cm^2) intensities - which should be found in the Recommended Operating Conditions table.

    Illumination source and special light requirements would be dependent on your final application and optics set up.

    Let me know if you have any other questions!

    Best regards,

    Trevor

  • 0 in reply to Trevor Dowd
    Prodigy 115 points

    Hi Trevor,

    Thank you very much for your answers! Its very helpful!

    Only one question :)

    Is it a must to operate a DMD-Chip with a pattern rate (frequency) or can the mirrors also stay  for a while in the same position (for example: -12° for 1 minute)?

     

    Thank you very much!

     

    Best regards

    Admir

  • 0 in reply to Trevor Dowd
    Prodigy 115 points

    one more question...and i hope the last...sorry

     

    in the datesheets i saw that the power density of DMD-Chips is in a range of 2-10 (mW/cm^2) (for example DLP5500 page 11) .

    Is that true?? Thats very small.

     

    Thanks!

    Admir

  • 0 in reply to Admir Asanoski
    TI__Expert 6370 points

    The DLP5500 is optimized for wavelengths between 420 - 700 nm. There may be power received outside that range below 420 nm and above 700 nm, but in smaller quantities 2 and 10 mW/cm^2 respectively, as you mentioned.

    For the optimized range between 420 - 700 nm, the power density is thermally limited (as noted in footnote 8 on page 11). The calculation to find this thermal limitation (if you follow the link in the footnote) can then be found on page 20 and will be specific to your application.


    Best regards,

    Trevor

  • 0 in reply to Trevor Dowd
    Prodigy 115 points

    Hi Tevor,

     

    you write that the power density is thermally limited. I looked in the datasheet but I'm a little bit confused. If i calculate the thermal limitation (for example 60°C) what can i do with this? How can i transfer the temperatur in power density unit (Watt or Watt/cm^2)?

     

    An other question.

    Is it a must to operate a DMD-Chip with a pattern rate (frequency) or can the mirrors also stay  for a while in the same position (for example: -12° for 1 minute)?

    Is the frequency at all mirror the same or can you control each mirror separatly?

     

    Thank you very much!

     

    Kind regards

    Admir

  • 0 in reply to Admir Asanoski
    TI__Expert 6370 points
    Hi Admir,

    Each DMD datasheet has a section on calculating the temperature of the DMD array. The calculation for the DLP5500, for example is on page 20 of the datasheet as I mentioned. This section also includes an example calculation that talks about the "Absorbed illumination energy," measured in Watts.

    When you have the temperature of the array, you can compare it to the Recommended Operating Conditions table to see if you are operating your DMD within the given specified limits. The DLP5500 has a temperature range of 10 - 70 °C, so 60 °C is within the specified limit.

    The frequency specification and operation of each DMD varies. If you tell me more about your end application or which DMD you are looking at specifically, I can answer your question more fully.

    Best regards,
    Trevor