• State
  • Locked Locked
  • Replies 4 replies
  • Subscribers 27 subscribers
  • Views 462 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.

birefringence effect for DMD window

CJ Rhee
Prodigy 65 points

I have a question about DMD window.
During the test with TI DMD (0.7 XGA 12º LVDS DMD Discovery) with polarized input light, we have found

birefringence effect and it is from DMD window, we think (probably stress birefringence).

I have found a few papers so far and it is about stress relieve of window sealing. It is also pending by TI.

 What we want to do is that;

-       Get some more detail information about DMD window sealing

-       How to remove stress birefringence

-       Is there any special model for stress free mount?

-       Can TI support to make stress free mount, if there is no special model?

-       Provide different idea to solve this problem.

  • 0
    TI__Intellectual 2265 points

    Hi CJ,

    For the DMD that you are using (0.7 XGA), it is in what is called a Type A package. In Type A packages, there is stress birefringence in the window due to the glass-to-metal seal process. It is not a problem for non-polarized light, which is an advantage for DLP projection. If using polarized light, it would be recommended that a wafer-level type (WLP) DMD package be used rather than a Type A package. This is thinner glass but should be less glass.

    The Type-A packages could be inducing a little additional stress by the mounting, to that which is introduced when the window is made.  The Type-A DMDs require loads be applied to the DMD to compressive contacts for making the electrical connection.  When making the electrical connection this may always introduce at least some stress.  The load applied to the center of the back for the thermal stud would add some stress.

    As an option, the LightCommander uses a WLP (Series 450) package on the 0.55XGA DMD. The chipset will be available shortly. This chipset will only be available initially for visible light only.

  • 0 in reply to WYA
    Prodigy 65 points

    Hello, thanks for your answer.

    In fact, Our application is lithography. so that we should use the UV light on the DMD.

    Is it possible to have a Tele-conference today(19th of April) or tomorrow(20th of April) ?

    Please, take a pleasure time for you. let me know the time.  

  • 0 in reply to WYA
    Prodigy 65 points

    Hello, Thanks for your answer.

    I have one more question. As you say WLP (Series 450) package, It VIS type. However, Does the 0.77XGA DMD with VIS also WLP package or not ? In fact, We should use 0.77 XGA DMD. In case, I just want to know whether 0.77 XGA DMD with VISUAL is WLP package or NOT ?

     

    Thanks

  • 0 in reply to CJ Rhee
    TI__Intellectual 2265 points

    CJ,

    The 0.7XGA DMD is not available in the WLP package for Visible or UV option. There is a 0.55XGA chipset that will be released for sale shortly. That 0.55XGA DMD is in the WLP package. You may find more information at www.ti.com/MEMS