How does OLED work?

There are additional flavors of 320x240 lcd display that are better for different kinds of devices. When a device only needs to display a static pattern with relatively slow refreshes—like the 240x64 lcd readout of a calculator or e-ink displays of the Kindle Paperwhite—you can use something called a passive matrix OLED (or a PMOLED). These work by turning on voltage to specific areas of the film and leaving them on until the device refreshes its instructions.Then there's active matrix OLEDs, like the AMOLEDs you might find in a smart phone. These are for high-definition applications that demand fast refresh rates, such as smartphone screens or HD televisions. AMOLED displays require a thin film transistor back-plane to actually drive each of the individual pixels, but this layer is just as flexible as the others, allowing for the development of rollable, foldable, transparent display panel prototypes.