Soldering LCD glass

Discussion in 'General Electronics Chat' started by RichardO, Feb 15, 2016.

  1. RichardO

    Thread Starter Well-Known Member

    May 4, 2013
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    Is it possible to reflow solder LCD glass? I am not talking about a module with electronics but just the glass portion. I am thinking of a very high volume application that would not have pins attached to the glass.

    These are the weaknesses that come to mind: Polarizer, metalization, seal, LC material, reflector. I have no idea which are likely to be a problem and which are not.
     
  2. Externet

    AAC Fanatic!

    Nov 29, 2005
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  3. SLK001

    Well-Known Member

    Nov 29, 2011
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    All of them would be a problem. LCDs are definitely not solderable. Like Externet says, use zebra strips or spring clips to connect to the.
     
  4. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Come on. It took the chemical & plastics industry years to perfect the zebra connector. Now you want to use solder on glass?

    Just joking. If you want to go that direction, you need to contact Indium Corporation. There are only two metals that will wet glass! Gallium and Indium. Stick with gallium for the price. Indium Corporation makes solders (tin, gallium, X, Y, Z alloys) that will solder to glass and silicon. Can you guess how lead wires are bonded to the chip and who supplies it? The gallium solders are very low temp and will not damage the glass but you will definitely need solder mask. Also, the conductive traces on the glass are indium-tin-oxide. That is all you really want to bond but the gallium solder is the way to go.

    Zebra is the way to go. Open up your fluke meter and you will see how they work.
     
  5. DickCappels

    Moderator

    Aug 21, 2008
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    Sometimes you can probably get away using a conductive paint or epoxy provided the connector pitch is not too fine and that your display and application can accept the slight increase in resistance.
     
  6. jpanhalt

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    Jan 18, 2008
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    Or ,tin the glass with Tollen's reagent (use the currently in vogue modification) then you might be able to solder to that. That's just an alternative, not a recommendation for LCD's.

    John
     
  7. ErnieM

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    Apr 24, 2011
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    Only open your meter if you wish to see what parts were used.

    Do not open your meter if you ever expect to see it working ever again.
     
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  8. GopherT

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    I've changed the display on a used fluke 87v. You just have to be careful and have a basic understand how a zebra connector works.
     
  9. RichardO

    Thread Starter Well-Known Member

    May 4, 2013
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    Actually, the soldering wouild be done to the tranparent metalization not to the glass.
     
  10. RichardO

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    I like the idea of conductive paint a lot. Cheap and simple! Since LCD's don't draw any significant current, the resistance is absolutely no problem. It could probably even be a carbon loaded ink saving the cost of silver or nickel.
     
  11. jpanhalt

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    The modified Tollen' reagent or classical Tollen's is pure silver and has very low electrical resistance -- much lower than "conductive" paint.

    John
     
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  12. RichardO

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    The low resistance is not needed here but you never know when it might be... :)
     
  13. ramancini8

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    Jul 18, 2012
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    I tried reflow soldering to an LCD for a gas pump display during 1977. Production could never get it to work (we used an IR heat source to reflow solder), so we went to the more expensive zebra strip. Problem with soldering is that some wires will come loose because of vibration, temp changes, and stress.
     
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