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Planning Is it possible to cut a TFT panel?

Discussion in 'Modding' started by silverdirk, 19 Mar 2009.

  1. silverdirk

    silverdirk has attained Nerdvana

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    Hi, I'm trying to fill a 16"x4" rectangle with an LCD screen. I don't have very much clearance in the housing, and I'd really love to have it all be one screen. (rather than installing multiple small screens) I'm not overly worried about price... lets say I'm willing to spend up to $500 for it.

    My question is this: Is it possible to take a large TFT panel with its electronics on the top and one side, and **CUT** the bottom of the panel off? (and of course build a new backlight) I'm imagining that as long as nothing gets shorted out, and the pixels are still connected to the upper and side electronics, they they should still change color properly.

    Anyone ever tried anything like this?

    Anyone have stories about accidentally breaking a display, and whether pixels above/below etc were broken or still working?

    Anyone have advice as to which brand I should buy for this stunt? Or how I should attempt the cut? (i.e. what tool, what direction, etc)
     
  2. null_x86

    null_x86 Thread Closer

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    you can simply remove the TFT display from its plastic housing and mount it in your housing... just make sure you take the proper care and handling of it, or else you'll be out money and a TFT display...
     
  3. Xtrafresh

    Xtrafresh It never hurts to help

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    That wont work for him, he wants 16" by 4", and they dont make THAT widescreen yet.

    I truely have no idea wether this is possible or not, but i think you should start practicing on old discarded 15" panels no matter what. Please let us know your findings, this is the stuff of legends :)
     
  4. Atomic

    Atomic Gerwaff

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    Cutting it that accurately without destroying all the pixels surrounding the cut would be impossible without industrial tools not to mention the electronics issues with changing the screen size without programming a new controller...
     
  5. Jenny_Y8S

    Jenny_Y8S Guest

    Nope it will never work, your only hope is to find a screen of the right size or change the housing
     
  6. Sir Digby

    Sir Digby The Supprising Adventures

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    +1

    Someone managed to lap an LCD so anythings possible!
     
  7. Xtrafresh

    Xtrafresh It never hurts to help

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    I guess electrically it just might be possible, if you convince the controller that 75% of the screen are dead pixels :hehe:

    It'll show up in windows as a normal screen, and you could never use the bottom as a "hard" edge to align stuff, but otherwise in very very raw theory, it should work.

    Practically there's probably a milion things that will go wrong, but that should never stop a real modder from TRYING ;)
     
  8. alpaca

    alpaca llama eats dremel

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    +1 for trying
     
  9. Smilodon

    Smilodon The Antagonist

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    Since the controller is normally mounted on the top and right side of the display, cutting the bottom could work. There is a few problems here, though:

    - The chance of shorting the VERY fragile traces on the glass is huge.

    - You are likely to crack the glass before you are able to cut it properly. If you DO manage to cut it, it's guaranteed that the pixels close to the cut will die.

    - The controller on the side of the dislay will also have to be cut. This mean that you have to figure out exactly how the controller works, and what components you can remove before things start dying.




    If you have enough room around where the LCD is to be mouted, you could always hide most of the display, leaving the portion you want visible. You will have to "cheat" a bit at the software side of things, though (You will have to to the same if you cut the display, BTW).
     
  10. silverdirk

    silverdirk has attained Nerdvana

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    I expect to destroy pixels at the cut. I'm planning to put a 1/2" frame around the panel to hide my handiwork.

    If you really mean it, you'd give me reasons ;-) This sounds like a dare.

    I was reading a bit on TFT tech, and I was thinking that maybe I could take a dremel and "brush" the edge of the cut outward, so in theory the tiny conductors would all be brushed parallel to eachother. I would then cover the edge in super glue.

    This part worries me. I might try to keep the chips electrically connected (and folded behind the display, possibly cut them apart and then join the unused ones back using wires). This way the display still thinks it is functional, but its signals don't reach the pixels.

    Can the controller tell whether it is connected to pixels? TFT just uses field effects to bend the crystal, so I'm thinking there's just a tiny capacitive load on the chips.... Maybe some resistive too, from the traces in the glass. If it were disconnected, would it care?

    The box is about 18"x5" and the window is approx 16"x4". I'll have some black framing around the picture, to hide rough edges, but I don't have anywhere near enough room for the height of a normal display.

    Cheating at software is no problem. I'm planning to connect it to an embedded SBC with a graphic accelerator, and then set my OpenGL viewport to the visible region, while letting X.org think that it is talking to a full 1600x1200 display. I'll only be rendering to a 1600x400 region of it.

    Even if noone knows the answer to this one, does anyone know where I learn more about what I'm up against? Or does anyone know a TFT engineer they could refer me to? I'm just a bit hesitant to ruin a good TFT, and I don't have any dying ones on hand. (hm, maybe i should go visit craigslist...)
     
  11. jhanlon303

    jhanlon303 The Keeper of History

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    How about?
    Before you cut anything, could you do the software mods first. Leave the TFT intact and as is and see if you can even do the long narrow window.

    My test stand LCD was cobbled together from 3 broken models of the same piece.
    LCD from one electronics from another and the case itself from the 3rd.

    Just thinking with you guys here.

    john
     
  12. silverdirk

    silverdirk has attained Nerdvana

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    Actually that part is really easy. They cover the relevant details in the very first NeHe tutorial I think (http://nehe.gamedev.net)
    Pretty much just SDL_SetVideoMode(1600, 400, etc etc). With no window manager running, the window will default to the upper-left corner.

    Interesting. What about the chips along the edge of the panel? did you swap those? or are they built-in?
     
  13. Smilodon

    Smilodon The Antagonist

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    Ok, so I was a bit bored this evening, so I figured I'd give this a go:


    Display working as it should:
    [​IMG]


    Back cover removed:
    [​IMG]


    Backlight removed:
    [​IMG]


    Testing after disassembly. Still working :):
    [​IMG]


    After the cut...:
    [​IMG]


    The problem here isn't electrical, and not cutting the glass. The problem is that the LCD is built up by layers of thick plastic film on top of a sheet of glass. When breaking the glass the crack didn't even follow the score line. The layers divided, and starter leaking. I guess you could maybe get this to work if you saw the glass in two pieces. A dremel with a diamond cutting blade could work.

    The chance of messing up is pretty big, though.


    At leas now you know that it's possible. Just don't blame me if you mess up. ;)

    edit: Oh, and the only reason for nor separating the display completely was that the only knife I had at hand wasn't strong enough to cut the plastic film holding the pieces together.

    edit two: 1: The picture is upside down because the cable was too short to hold it the correct way in front of my monitor (Needed a bright background). 2: There is two dead columns of pixels to the left in the cut display. I'm not sure whether this is because of the cracking or me not being gentle enough with the controller board cable. 3: The cool thing about laptop LCDs is that the chips on the side of the display are very small, and connected differently than on larger displays. This means that getting a glossy display and using it as a case window could work very well. :)
     
  14. Sir Digby

    Sir Digby The Supprising Adventures

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    I can't really tell from the image - but does the top half of the screen still show an image?

    If so the possibility of something like laser cutting the screen seems, well, not quite completely insane...
     
  15. Smilodon

    Smilodon The Antagonist

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    Nope. The top half doesn't show any image it's completely white and have a crack in it. (The top in the picture. Where I'm holding the display) It's physically disconnected as the traces was cut when scoring the glass.
     
  16. silverdirk

    silverdirk has attained Nerdvana

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    Nice! Thank you! You've given me some hope, and some first lessons.

    I'm still in the process of getting some old dying TFTs from friends. One of them mentioned that they think that the liquid crystal will dry out as soon as it is cut. Is that maybe what caused those large black splotches? If so, I might need to try this under a tank of oil, or water, or something. Maybe apply a bead of hot-glue along the cut immediately behind the dremel. A high-speed band saw with a fine blade might work a lot better. hm.

    The way I'm planning to attempt this is by taking my sacraficial displays and repeatedly cutting small strips off the bottom. This should give me enough practice to go for the final cut on the actual display I use for the project.

    Anyway, Thanks! And I'll post pictures when I finally try it myself.
     
  17. Smilodon

    Smilodon The Antagonist

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    I don't think they are drying. It's the LC that's running freely around inside the display. As long as the layers are kept perfectly together it shouldn't be any problem as far as I can see.
     
  18. Sphering

    Sphering New Member

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    This thread is just up my ally. Awesome try Smilodon, nothing is as fun and educational as the methode of trials and errors when modding. Keep trying guys. Will watch this
     
  19. Nexxo

    Nexxo * Prefab Sprout – The King of Rock 'n' Roll

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    :hehe: This is too epic for words.

    There is NO WAY that you can cut a TFT screen and still have it functioning properly. Let me repeat that: NO WAY.

    Smilodon has already demonstrated the result (shame of a good screen, though, even if it is a laptop screen that cannot be repurposed easily). Cutting a TFT is much like cutting a silicon chip: no matter how fine the scalpel, how careful the conditions etc., you will wreak uncontrollable damage to the delicate structures that are part of the functionality of the object. It just cannot be done.
     
  20. KayinBlack

    KayinBlack Currently Rebuilding

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    I'll second, and add some more information. Those controller chips are built for the native resolution, and cannot be reprogrammed. Cutting them just destroys information and displays.
     

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