Hi

I recently bought a very cheap bit of chinese electronic junk and the first thing that happened was that one of the plugs fell inside the box so I had to get the the screwdriver out within minutes of getting it.

This thing has a processor of some kind and an LCD display. What I found was the circuit board (with the processor) is not attached to the display by the usual sort of ribbon cable or edge connector but this wierd sort of foam rubber sandwich affair which seems to rely on being squished between a line of contacts on the circuit board and the display itself.

If you hold the display up to the light there seems to be a 'matching' set of very faint contact lines on the edge (where the other side of the foam rubber sits) which I assume is some sort of conductive layer.

I'm assuming this 'foam rubber' thingy also contains some sort of conductive material, but how the whole thing keeps in line god only knows which is probably why the display is pretty flaky at the best of times (and if you dont get the right amount of squish and alignment it won't work at all)

Any pointers or any info on what this thing is and how it works gratefully received !

Thanks, Si

 

The rubber thingy is the connector for the LCD to board

 

It is a fairly standard way of making contact between the metalized contacts on the glass and the mating PCB contacts. Just have to put the strips in position and carefully join LCD and PCB with the strips in place then fasten it with whatever clip or other mechanism is provided to hold it in place. You will likely have to try the process one less time than it takes to frustrate yourself out of your gourd before you can get it to work. Than and only then will you be authorized to break your arm patting yourself on the back for doing it. You must also sware to never take it apart again. But the reward is that you will get to brag to your friends and associates that you did it. Obtion B is to call the Chinese manufacturer for technical support.

 

Thanks for your thoughts guys, that all seems to hang together.

I like the sound of Option B - that could make a fun way of spending an afternoon (and a lot of money) !

I'll give myself a small pat on the back, as the thing is working at least as well as it ever was, which as I said wasn't brilliant.

I'm assuming the 'filling' in the rubber sandwich must have individual conductive channels somehow, otherwise the whole thing is just shorted out, but the odd thing is it looks like one smooth layer, which is what made me wonder how on earth it worked.

The critical bit of the alignment seems to be between the PCB and the display, as there is nothing to stop the rubber moving 2-3mm either way and it doesn't seem to make much difference. I'm assuming there are many more channels in the rubber than it needs and if you move it a bit, it just uses different channels ?

Does this thing/technology have a name? I would have thought it could be someones patent idea, as it is actually pretty nifty.

 

It's called an Elastomeric connector with a trademark name of zebra connector.

We've used something similar from Fugipoly where it is about a 1 inch square where it has very numerous tiny connectors covering the entire 2d dimensions. We use it to connect tiny parts to a PCB during test.

 

Excellent - mystery solved !

Thanks again all.

 

Check this website http://maverickelectronic.blogspot.com/ for troubleshooting on LCD module

DumbDummy77