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DLP4710: TRP explanation and/or illustration not correct or confusing?

Mike Sh.
Expert 1405 points
Part Number: DLP4710

So after passing an article to my optical engineer I noticed either the diagram or the illustration of TRP angles is either not correct or confusing.

This is what I mean:

"DLP TRP pixel architecture utilizes square pixels and tilts by 17°. The mirror first tilts by 12° along the hinge then rolls by 12° to either ON or OFF position, resulting in a compound 17° angle."

Then there's this illustration on this page:

It looks like in the illustration the micromirror has rotated 12 degrees in one axis and 90 in the other?

  • 0
    TI__Mastermind 28005 points

    Mike,

    Thanks for your question. Can you describe which axis you are referring to that is tilted by 90 degrees? To help with the discussion, You can also refer to the TRP pixel diagram in page 3 of this DLP Technology Overview document:

    http://www.ti.com/lit/ml/dlpb010e/dlpb010e.pdf

  • 0 in reply to Philippe Dollo
    Expert 1405 points

    Hi Philippe, this is what I mean:
    https://imgur.com/a/DnwJc2G

    I just took the illustration I posted in the original post and added a flat model on top, rotated 12 degrees, moved it on the illustration on the other side, then rotated 90 degrees there so they would match.

    I don't see how 12 degrees rotation in one then any other axis would give the same result.
    Either something is wrong with that illustration or I'm missing something.

  • 0 in reply to Mike Sh.
    TI__Expert 4610 points

    HI Mike,

    Please do not confuse with the image shown here :

    the correct explanation of the TRP is mentioned in the document you referred :

    For visual experience please see the image Philippe shared with you.

    Thanks,

    Navneet

  • 0 in reply to Navneet Singh
    Expert 1405 points
    Sorry, but you just said the same thing as Philippe to which I've responded?
  • 0 in reply to Mike Sh.
    TI__Expert 4610 points
    Mike,

    I can not visualize you the mirror movement from here. but i would like you to do the one experiment for better visual understanding.

    Please take a square notebook and first tilt it at one corner then roll it in the left and see the position of all four points and then do the same after rolling it to right and see the position of all four points. you will get to know the position matches with the images shown in the guide. There is no 90 degree movement.

    answer to your query - Mirror first tilt 12 degree along the hinge then roll 12 degree left and right.

    I hope this helps your query.

    Thanks,
    Navneet
  • 0 in reply to Navneet Singh
    Expert 1405 points

    I'm sorry but this is again not helpful at all.

    You're rephrasing what is said in the PDF and suggesting to do you it myself with a notebook. Do you not think I've actually done it in a 3d editor? I've even generated a 3d animation to show the issue and you have not checked it or not explained what part is wrong. Unless you specify , preferably visually, what exactly you mean by tilt and roll when it comes to your micromirrors, it is simply impossible to achieve that rotation in the illustration with two 12 degree rotation.


    It's very possible the hinge mechanism makes the roll and tilt of a flat mirror behave differently than tilting and rolling any object in real life or 3d but we are not TI engineers here to guess how it works yet we need to know how it works to not waste thousands designing a broken optical engine.

    Furthermore hinge can rotate only in one axis unless you have a part that acts more like a ball socket joint which will act very differently when the mirror then rolls as well. Explanation is in order, preferably an animation of the rotation. Arrows from the PDF don't tell much, if you have arrows usually its circular arrows along a rotation plane, not just by themselves. The tilt arrow just goes down which isn't even a rotation visualization arrow.

  • 0 in reply to Mike Sh.
    TI__Expert 4610 points

    Mike,

    Please see the attached file, you will get the idea of mirror movement.

    Mirror_Movement.pptx

    Thanks,

    Navneet

  • 0 in reply to Navneet Singh
    Expert 1405 points
    I'm sorry but that powerpoint appears to have a single slide containing a single bitmap image which I've uploaded myself here?
  • 0 in reply to Mike Sh.
    TI__Expert 4610 points
    Mike,

    Please run the slide show in your ppt.

    Thanks,
    Navneet
  • 0 in reply to Navneet Singh
    Expert 1405 points
    My apologies.
    I still don't see how this is a 2D hinge rotating but I see how it works now. I'd suggest to put this as a gif in the webpage. I can generate one from the ppt if needed.
  • 0 in reply to Mike Sh.
    TI__Expert 4610 points
    Thanks for the suggestion Mike :)

    I will discuss with my team and try to update on web page.

    Thanks,
    Navneet