Question about LCD contact strips
Does anybody know what thsoe strips that make edge contact with small LCDs are called? Looks like I have some defective one.
------------------PCB || || <- conductive rubber strip ||_____________ || ================== LCD front
Zebra strips.
I believe they are Zebra strips, but that seems to be a trademark. Generically they are "Elastomeric connectors".
There are also some featureless elastomer things that have vertically aligned slivers of conductive metal.
That's what everyone is talking about, Zebra strips. Obviously, you didn't use the link.
The zebra strips have (black) conductive and (non-black) non-conductive stripes hence the name. That differs from the silver-needle packed rubber that Larkin mentioned (he wrote 'also'). I know that as expensive but good EMC shielding stuff. Featureless, unless under a microscope.
A.
On a sunny day (Tue, 2 Aug 2022 15:27:42 +0200) it happened Arie de Muijnck snipped-for-privacy@ademu.com wrote in snipped-for-privacy@ademu.com:
Thank you!
On a sunny day (Tue, 2 Aug 2022 06:27:52 -0700 (PDT)) it happened Ricky snipped-for-privacy@gmail.com wrote in snipped-for-privacy@googlegroups.com:
OK, thanks, after googling for 'elastomeric connectors' I found some site that makes those
Right. I never considered a zebra to be featureless.
The zebra conductive elastomer strips (plainly visible) are not very good electrical conductors, but plenty good enough to connect an LCD. The vertical sliver things are hard metallic conduction paths.
Ricky "Obviously" wants to argue and insult but doesn't want to think.
Wow! Some people are very sensitive.
A zebra strip has visible bars, which are significantly more narrow than the pads and gaps on the PCBs being connected. So you don't need to worry about shorting between pads. I had not heard of these other strips before. I have learned something today.
The 'conductive rubber' strands are side-by-side with insulating separators, end-on it looks like a dotted line. These are elastomeric electrical connectors, of couse, but they aren't the ONLY elastomeric connectors; I have seen cylindrical ones with many circular bands of conducting material.
Good luck looking for replacement; the length, breadth, and pitch of the conductors are all variables that you'd want to match. Conduction-dimension length, particularly, is critical; one cannot trim that with scissors and get good results. Thickness, to fit the channel, could perhaps be allowed undersize, and fit in a bit of plastic shim alongside.
Sometimes an isopropanol wipe and reseating is all a 'damaged' strip needs for repair.
Search for z-axis conductive tape
It might replace a zebra without having to match pitch or pattern. Amazon has some.
Larkin doesn't read my posts, but he should understand that zebra strips have a much finer pitch of the conductive stripes, than the pads, so there is no need to match the stripe pitch to the pad pitch. There will always be multiple conductive stripes on a given pad and multiple insulating stripes between pads. These only work with single row pad arrays, but do not need to match the pads in terms of width. The height of the zebra is important and the length a bit less so as it only has to cover all the pads.
You don't have to match the pitch with Zebras--that's one of their main selling points. The board has to match the glass, is all.
I used them in my Footprints sensors to connect to the metal (later carbon ink) pixels on the free-standing 9-um PVDF pyroelectric film.
Cheers
Phil Hobbs
Cheers
Phil Hobbs
Surely a coarse pitch will short out or miss a close pad pattern. And getting them crossways or angled is bad.
Fujipoly makes zebras at 100 to 500 contacts per inch.
There are also Z-wrap connectors, an elastomer shape with wires wrapped around or inside as the conductors. They get down to numbers like 0.004" pitch.
We're talking about LCD contacts, which aren't super fine in general. I sure wouldn't use a Zebra when a misalignment of a few thousandths mattered. For coarser stuff, you just toss them in and you're done.
Cheers
Phil Hobbs
The cheap stuff is solid rubber wrapped in plastic with foil stripes
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