[opsomath]

Hi all, I have some experience working with indium tin oxide (ITO) coated glass surfaces as a transparent electrode. These materials are expensive. It has occurred to me that flat screen LCD monitors contain a pair of ITO electrodes the size of the screen. Flat screen displays which have a failed backlight can usually be found in dumps or for cheap on eBay, and I was wondering if the construction of these devices would make it possible to disassemble them to recover and reuse the sheet electrodes. Are the ITO electrodes in LCD panels printed on glass or plastic? Is the ITO side coated with anything?

Thanks!

[Enthalpy]

Maybe the proper deposition of ITO is not very cheap, but the material cost is just tin, or nearly nothing in a thin film - ad this is what you would scrap...

[opsomath]

I'm sorry, I didn't quite get what you were saying. It is common in research to buy glass slides coated with ITO, which cost something like a few hundred dollars for a small package. I was wondering if it might be possible to substitute a part salvaged from a LCD for these parts.

[Enthalpy]

Oops, thanks for the explanation.

My gut feeling for LCD used in transmission: they should have a glass substrate, maybe an integrated light polarizer, possibly a set of narrow lower electrode lines, a lower ITO layer already patterned, some liquid crystal layer, an upper ITO layer already patterned, an active layer of TFT, maybe a set of narrow upper electrode lines, a light analyzer if it's integrated, and a strong layer as chemical and mechanical protection.

Chemical etching would have to remove the protective layer plus several layers; the liquid crystal must be much more soluble in some organic sauce than the underlying ones. But then, what will you do with the patterned ITO layer?

Typically, a display screen has horizontal lines at the lower layer and vertical ones at the upper, so that each pixel is addressed.
http://en.wikipedia.org/wiki/LCD

[Enthalpy]

ITO is the standard answer each and every time a transparent conductor is needed - in fact, the choice is very narrow...

But if you need a limited current density, could surface leaks suffice? Imagine that you pattern very narrow metal lines on your transparent substrate, very close to an other: more than two lines per wavelength will let them appear continuous, and metal much narrower than the separation reduces the reflection or absorption.

Then leaks at the surface of the substrate have only to cover the last 100nm to spread from the metal to the whole surface, and all leaks are in parallel. You can also increase leaks by deteriorating the substrate's surface, say by plasma implantation.

Imagine lines separated by 200nm: at 1cm², the Rsquare is divided by 2*10¹⁰, which is adequate for some uses.

[opsomath]

Your metal lines idea intrigues me, but I'm not sure what it's for exactly. Are you saying that  you'd use the printed lines to create a surface with a limited conductivity?

[Enthalpy]

The metal lines would first spread the current with little loss, then surface conductivity would suffice (in some cases!) to bring the current over a very limited distance and a huge width.

If the metal lines are narrow enough one won't see them, not even through the grating effect if they're closer to an other than half a wavelength.