FYI, I've learned a few details that might be helpful to OLED investigators:
The 4D Systems (Sydney) uTOLED-20-G2 2" 160x128 "Transparent" color OLED panel, said to be "... perfect for Head Up Displays" is neither transparent nor likely usable as a HUD. (http://www.4dsystems.com.au/product/1/5 ... LED_20_G2/)
The panel is not optically clear; not surprisingly, it's more like lightly-ground glass, translucent due to the OLED pixel matrix and the necessary conductive row and column wiring. Further, the pixel intensity is low, all-but-invisible outdoors in daylight.
https://dl.dropboxusercontent.com/u/917 ... 810-2.jpeg
https://dl.dropboxusercontent.com/u/917 ... 5743-2.jpg
And, if one is tempted to buy an inexpensive Chinese 128x32 mono OLED module on ebay (http://www.ebay.com/itm/I2C-0-91-128x32 ... 2574dbe1c6), be aware that the module lacks a Reset line (unlike the Adafruit version (http://www.adafruit.com/products/931#Downloads), which has a Reset logic input).
As best I tried, it appears impossible to fully return the ebay module to the Reset state with commands alone - more often than not leaving the "Line 0" register in disarray or malfunctioning, displacing the display vertically when restarting application code. The module draws little current (~12mA or so, all pixels on), though, so powering it from a 5v logic line - dropping it for 100mS to reset the display - works.
[Later edit: I found it necessary to also lower the two I2C lines (-24n pins 11 and 12) to avoid back-powering the OLED through the I2C pullups; lowering the power pin alone proved unreliable. The Adafruit module (product 931) behaves identically if the reset line is not used.]
These mono (white on black) displays, too, are not suitable in outdoor ambient illumination, but look great (albeit small) indoors.
