While reusing old displays wasn't initially the goal of this project, the goal of making it affordable lead straight in that direction, and then the Hackaday Prize came along with this category, so I thought why not submit it.
But while no lone hacker is going to save the planet with our toys, we can at least help somewhat by raising the awareness of the environmental effects of the technology we are using. So I went and tried to do some research about how bad the displays actually are for the environment.
On the surface of it, the impact seems negligible. It's mostly glass, silicon, some mild chemicals for the liquid crystals, some metals for the contacts, plastic for the case. But it turns out that most thin displays, whether they are LCDs, OLED, plasma, TFT, IPS or e-ink, share one thing with thin-film photovoltaic cells that makes them horrible for the planet: transparent electrodes. Of course you need transparent electrodes to bring electricity to all those pixels, if you want to also be able to see the pixels. Such electrodes are usually made of silicon, just like in chips, and to get the right shapes, they are etched in similar way that you etch copper on the PCBs. Except the best chemical for etching silicon is nitrogen trifluoride.
What is nitrogen trifluoride? It seems pretty harmless. It's colorless, non-flammable gas with pretty low toxicity. Easy to handle, pretty safe. However, it's an extremely potent greenhouse gas. How potent? 17200 times more potent than carbon dioxide. That's 17 thousands. Oof! It stays in the atmosphere for an estimated 740 years. And its concentration in the air is growing steadily at about 11% increase per year, as of 2011.
So yeah, let's see if we can reuse those displays we already have, and maybe rethink those solar panels a bit too.