What Can You Do With A Broken LCD Screen?

Not much.

But there are ostensibly some things you can do with a broken LCD panel. I found a small one in my box of stuff that had its ribbon broken off during moving. Unfortunate and (for me) unfixable. But can we salvage parts from the LCD screen and, perhaps most importantly, make use of it

This is the LCD in question. The data ribbon tore at the screen, so we can no longer use it. This is extra sad because it was attached to logic that displayed a composite signal and I was going to use it in a future project. But, alas, there's probably a replacement screen or a better way to do that whole thing now that this is broken.

Anyway, it's useless to us like this, so let's pry it open. front bezel pops off by wedging some clips.

Here we have the LCD's two principle components: the LCD layer and the backlight layer. I won't go into too much detail with the backlight since it's the easiest to deal with and I forgot to take pictures of it. But inside of this one (and most others) I found a fresnel lens sheet and a small row of LEDs that illuminated the clear material behind the lens. Turning this on is a matter of putting a voltage across its ribbon. Experiment with voltages, starting low until you get bright enough light from the backlight. And always be sure to use a current limiting resistor.

The LCD panel took some poking to get it to do anything. I wasn't able to make it do anything too special, although when I ran five volts across some test points I was able to control the opacity of the screen which was pretty neat.

I had to scratch off the silicon covering to get to the actual contacts.The most drastic change was when I put the voltage across the top and middle pads. One polarity darkened the screen, the other made it more transparent. If you picked the screen up and your finger touched the exposed pads or the ribbon that was left on the bottom, the screen would discharge and turn opaque again. I don't know too much about LCD technology, what these pads actually correspond to,

On the other side, the pads are labeled much better, but I still don't know what they mean. I can only guess at what these mean, but this website explains in much more detail how LCD driving circuitry works, and if you're interested, you may be able to glean something from that.