• State TI Thinks Resolved
  • Locked Locked
  • Replies 9 replies
  • Answers 2 answers
  • Subscribers 29 subscribers
  • Views 508 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DLP7000: DLP products forum

shixuerong
Prodigy 30 points
Part Number: DLP7000

Tool/software:

hello,

 I have a more confused question to ask，when I tested I found that the dlp7000 affects the polarization state of the incident light. For example, the horizontal line polarization  reflected by the mirror and can be extinction by  vertical angle of the polarizer .However, if reflected by the dlp7000  found that there is no extinction, and even the uneven state, what will be the reason for this phenomenon.

Looking forward to your reply.

  • 0
    TI__Guru 54320 points

    Hello Shixuirong,

    To be sure I understand could you draw a diagram of what you mean.

    My understanding of what you wrote is that what you are observing is likely the Brewster effect on the incident beam at the window interface.

    Fizix

  • 0 in reply to Fizix
    Prodigy 30 points

    Thanks for your reply. 

    The polarization state of the light emitted from DMD is uncertain. I want to know the reason for this phenomenon, and it seems like some dlp7000 have not this phenomenon just like a mirror can extinction the light.

  • 0 in reply to shixuerong
    TI__Guru 54320 points

    Hello again Shixuirong,

    I will need to talk with the optics team about this.  Please allow a day or two.  I should get back with you on Monday Aug 16.

    Fizix

  • 0 in reply to Fizix
    Prodigy 30 points

    Thank you very much and look forward to your reply.

  • 0 in reply to shixuerong
    TI__Guru 54320 points

    Hello again Shixuerong,

    I will let you know when they reply.

    Fizix

  • 0 in reply to Fizix
    TI__Guru 54320 points

    Hello Shixerong,

    I spoke with the optics teams.  The type A packages have significant birefringence in the window glass.

    The optical team cannot think of any other thing that should be affecting it this way.  they would like you to rotate the polarizer on the output through 180 degrees to see if there are points along the way that have minima and maxima.  Please let me know the results.

    Fizix

  • 0 in reply to Fizix
    Prodigy 30 points

    Okay, thank you so much, we tried to rotate, and the max and min cases did, but the light is still there at the minimum.

  • 0 in reply to shixuerong
    Prodigy 30 points

    Hi Fizix

     We understand that the polarisation may change due to the  significant birefringence in the window glass. A single polarisation state can be obtained using a polariser at the output position. However, there is ghost images come with this phenomenon, for example, a single focus point cannot be created via binary amplitude modulation and there is always multiple (ghost) points, which we think are from the multiple reflection between two surfaces of DLP cover glass. The ghosts make the DLP not usable for our application. Please give some advice and provide a solution.

    The left is before optimisation,and the right is after optimisation. Apart from the primary focus/point in the middle, there are ghosts can be seen.

    Shixuerong

  • 0 in reply to shixuerong
    TI__Guru 54320 points

    Hello Shixuerong,

    Regrettably it is not possible to completely get rid of these reflections. Is there a reason why you need to use the s polarization?  The p polarization will likely reduce the intensity of some of the reflections, but the second interface (window to DMD interior on the incident light) will still have some reflections.

    Fizix