Electrical contacts on glass ?

[mauros]

Hello everyone,

i would like to know whether by gluing a conductive copper wire over an conductive trace on the glass of a display,

http://tim.cexx.org/projects/goldlcd/traces.jpg

i get the electrical contact or not.

[mikeselectricstuff]

That looks like a zebra-strip connector - conductive paint/epoxy would work but would be tricky to avoid shorts.
For a 1-off it might be worth trying z-axis tape onto a PCB

[mauros]

Maybe, maybe not. Some of the traces are passivated, which means there is a thin layer of dielectric (glass, etc.) on top of the trace, so you can't probe it from the top.
Even if you can, conductive glue will short adjacent traces, so what's the point?

I have a display where the flex cable was removed and in backlight i see the ITO traces as in the picture at the link. I have to reuse that display and i would like to find a way to hook a flat cable.

Any suggestions ?

[Karlo_Moharic]

Check out this video:

[BrianHG]

That looks like a zebra-strip connector - conductive paint/epoxy would work but would be tricky to avoid shorts.
For a 1-off it might be worth trying z-axis tape onto a PCB

Also known as:
https://en.wikipedia.org/wiki/Elastomeric_connector

[mauros]

That looks like a zebra-strip connector - conductive paint/epoxy would work but would be tricky to avoid shorts.
For a 1-off it might be worth trying z-axis tape onto a PCB

Also known as:
https://en.wikipedia.org/wiki/Elastomeric_connector

I can not use the Zebra strip connector because the display socket is not flat and smooth but has the steps  _-_-_-_-_-_

[mauros]

Check out this video:

The technique you posted is interesting but i do not have to create a pcb on the glass, i have to connect some wires on the already existing traces on the display glass 

[BrianHG]

My old LCD shutter lens for my glasses used these metallic clamps, however, they came from the LCD manufacturer as shown in the image below:

Buy a cheap 1$-2$ type LCD with these clamps.  Note that there is a coating of glue of the clamps to hold them in place.  You need to find a way to get rid of it.  Maybe heat like from a SMT hot air gun as the glue is similar to crazy/super glue and may be evaporated away at high temperature.  Clean off the pins and re-squeeze the spring on them and attach to your LCD & use a thick gel version of crazy/super glue to solidify their position.

[mauros]

My old LCD shutter lens for my glasses used these metallic clamps, however, they came from the LCD manufacturer as shown in the image below:

Buy a cheap 1$-2$ type LCD with these clamps.  Note that there is a coating of glue of the clamps to hold them in place.  You need to find a way to get rid of it.  Maybe heat like from a SMT hot air gun as the glue is similar to crazy/super glue and may be evaporated away at high temperature.  Clean off the pins and re-squeeze the spring on them and attach to your LCD & use a thick gel version of crazy/super glue to solidify their position.

WOW it would be magical, but unfortunately my LCD has the 28 traces that converge in little space ( 16 mm approximately )

http://oi64.tinypic.com/313ot3s.jpg 

and i can only get the electric contact by inserting a flex cable  ( pratically impossible ) or individual wires into the slots

[BrianHG]

The standard high density pin pitch as shown in picture 1 below is 1.27mm.
Your LCD is most likely double that density, or 0.625, or maybe even a true metric 0.5mm pitch.
You need special flat flex connector with conductive glue on the gold pins, with no glue in-between to press fit on the lcd.  something special which lcd manufacturers have, but I do not know where to buy.  See photo 2 (your looking for a finer version of that...).

[ovnr]

You need special flat flex connector with conductive glue on the gold pins, with no glue in-between to press fit on the lcd.  something special which lcd manufacturers have, but I do not know where to buy.  See photo 2 (your looking for a finer version of that...).

No, you need anisotropic glue, which is applied with a bit of heat and pressure, and forms a conductive path in the (very thin) Z axis, but does not conduct in the X and Y axis. It's what's used to assemble these things in the first place.

To OP: Did your display have a flex on it? If it got ripped off, the display may very well not be recoverable, no matter how much you try.

[mauros]

The standard high density pin pitch as shown in picture 1 below is 1.27mm.
Your LCD is most likely double that density, or 0.625, or maybe even a true metric 0.5mm pitch.
You need special flat flex connector with conductive glue on the gold pins, with no glue in-between to press fit on the lcd.  something special which lcd manufacturers have, but I do not know where to buy.  See photo 2 (your looking for a finer version of that...).

My display has pitch 0,5 mm and i do not think that at home I can glue a flex cable that was originally press-fitted and heat-sealed.

[mauros]

My display is one of the 3 found in this equipment
https://medias.audiofanzine.com/images/normal/zoom-g3-548281.jpg

and from the map I wrote to myself

- I understand that the pins 12 and 13 are respectively Vcc and GND that put ON / OFF the 3 displays at the same time.
- I found that some pins are not connected (NC)
- I found that some pins are connected to GND
- but I do not have the experience to understand the meaning of the pins connected to the capacitors (including the charge pump)
- if I understood it, I could buy a compatible LCD and, through an adapter like this

https://tinyurl.com/y78a4dk9

I could connect the flex on the narrow side and I would weld on the other side the wires that from the old LCD went to the mainboard and that I have patiently already derived

http://oi67.tinypic.com/qxtr34.jpg

[mauros]

I finally found the pinout, this https://tinyurl.com/ybtyac7y

Now I have to find an LCD of the same size as mine https://ibb.co/nJWFGb,

with ST7565R controller and so I can adapt its pins to the motherboard of my equipment.

Meanwhile, I wish Happy New Year to all 

[ovnr]

This seems to be fairly close, size-wise, and has the right controller:

http://www.buydisplay.com/default/2-1-inch-cog-serial-spi-128x64-graphic-lcd-display-module-arduino-black-on-white

Edit: Also, I should note that just because it has the right controller doesn't mean it'll work - the initialization code can vary, and you may find that the drive levels, etc that the firmware in your device writes to the LCD is wrong for a different display.

[mauros]

This seems to be fairly close, size-wise, and has the right controller:
http://www.buydisplay.com/default/2-1-inch-cog-serial-spi-128x64-graphic-lcd-display-module-arduino-black-on-white

thx 

Edit: Also, I should note that just because it has the right controller doesn't mean it'll work - the initialization code can vary, and you may find that the drive levels, etc that the firmware in your device writes to the LCD is wrong for a different display.

Why can this happen ? Have you had such an experience with 2 apparently equal displays?

[ovnr]

Why can this happen ? Have you had such an experience with 2 apparently equal displays?

I've written firmware to control various displays. The parameters vary by quite a bit.

Take RGB displays, for instance: There are a few displays with the same controller, but different subpixel arrangements. If you swapped it without changing the controller firmware, you'd get a rather wrong image. The same applies to monochrome displays, but more subtly - the drive voltages can differ, some controllers are slightly wider than the display (132 px wide vs 128), and the connectivity can differ leading to a cropped image, etc.


Have you tried to get an original replacement, or to get the device serviced by the manufacturer?

[mauros]

I've written firmware to control various displays. The parameters vary by quite a bit...

so there can be problems even with the same controller and pinout?

Have you tried to get an original replacement, or to get the device serviced by the manufacturer?

The company does not release spare parts but the service center, unique in Italy, can sell me a display at € 22, but after all the time trying to resolve, it has become a matter of principle. Maybe in the end I give up and buy the original display

[cs.dk]

Maybe it's just me - €22 for a brand spanking new, i wouldn't even spend half an hour on it.

[mauros]

Maybe it's just me - €22 for a brand spanking new, i wouldn't even spend half an hour on it.

€ 22 without VAT and without shipping costs

[ovnr]

so there can be problems even with the same controller and pinout?

(snip)

The company does not release spare parts but the service center, unique in Italy, can sell me a display at € 22, but after all the time trying to resolve, it has become a matter of principle. Maybe in the end I give up and buy the original display

Yes, even with the same controller and pinout.

At €22 - or even €50, to be honest: Just buy the spare part. Sure, you MIGHT be able to bodge a €15 display in there that might work. Is it worth the effort? No.

[mauros]

At €22 - or even €50, to be honest: Just buy the spare part. Sure, you MIGHT be able to bodge a €15 display in there that might work. Is it worth the effort? No.

I understand very well what you mean, moreover in the flea market the complete device
https://i.ebayimg.com/images/g/49sAAOSwfjRaJqvb/s-l225.jpg

is already at € 60 and last year I have already bought one but I would not buy another one 

At the limit, I could try to recover the display without more flex using the conductive paint I have in some drawer, finding a way to fix thin wires in the display socket

[mauros]

I asked to customer service to buy a single display from them and they replied that, since do not sell spare parts, should remove it from an equipment located in the repair center and, to discourage me from buying it, they would not guarantee me the correct functioning ( they would not even test it), and rather encouraging me to buy a new device (WOW !!). As if these devices were disposable: absurd !!

At this point, I prefer to try with a compatible display, risking also that it does not work, but for this reason that does not cost more than 5/6 €, and in the meantime i found this with 18 pins

https://it.aliexpress.com/item/18PIN-Grey-Backlight-COG-12864-LCD-ST7565R-Controller-3-3V/2053945961.html

identical pinout of the module referred on the back of the original one,

http://www.datasheet4u.com/datasheet-pdf/ETC/SMMC12864/pdf.php?id=934845

but it is too small.

[mauros]

Having to look for a display that fits me, I have looked and reflected on its size and probably I think it is very important that the active area is not smaller than what i need or not? (Maybe even the number of horizontal and vertical pixels?). For a check, I turned on my device and I noticed that, on each display, the largest area occupied by an icon is equal to 39 mm x 27 mm (see lines blue in the picture) and I wondered if that area really represented the maximum active area of the display.

What do you say?

[mauros]

Yes, the active area is just that and to confirm this, the number of pixels on the horizontal (128) and those along the vertical (64) correspond to the characteristics of the display (128x64)