Scientists Add Touch Capabilties to OLEDs
All LED's (OLEDs) can sense light
Each pixel is effectively its own independent sensor, so the technology could also be multi-touch. Infact, it should have the complete raster outline of the object touching it, so it would be even better than capacitance.
This is a very strange and misunderstood property...if you are interested, you can do some research on theory and a few implementations of this.