Originally Posted by Isochroma
OLED has true shades of colors - unlike plasma which switches pixels on and off to get greyscales. Switching pixels to get greyscales causes motion artifacts, and can even be seen on still images in dark areas due to low duty cycle. These effects are often called dither or 'noise', though they are not noise in the normal sense of the word, but switching artifacts also known as temporal aliasing.
OLED emitters can have a much wider color gamut (better purity) than plasma phosphors.
OLED doesn't flicker like plasma because it doesn't require PWM switching to obtain greyscales. Distinct and present in addition to 'noise' or temporal aliasing as mentioned above, the entire display strobes at one or more frequencies (usually 60Hz. in North America). This artifact is more visible in bright images from all distances and can causes headache and eyestrain.
OLED uses much less power than plasma because unlike plasma it does not require high voltage to ionize gas. Converting wall current to high voltage uses expensive, heavy and failure-prone circuits that waste energy during the conversion process. Plasma also uses many different high voltages, further complicating the conversion circuitry.
OLED is safer than plasma because the unit contains less high-voltage circuitry. In case of accident like water infiltration, etc. it is less likely to cause electrocution. A plasma steps up the 110-120V wall current to 600V to activate its pixels, while OLED converts its input voltage down
to 12V or lower. 12V or lower cannot cause electrocution and is safe. The only dangerous circuitry in a wall-powered OLED is the small portion before and inside the step-down converter - all the rest runs at or below 12V. For OLEDs used in laptops, cellphones, and other battery-powered devices there is no dangerous voltage at all. Even compared to LCD - the majority of today's LCD small-device displays use cold-cathode high-voltage miniature fluorescent tubes for backlights and therefore also present a shock or electrocution hazard.
OLED drive circuitry lasts longer than plasma drive circuitry because its power usage and voltage are much lower, and its circuits are less complex with far fewer high-power handling components which are usually the first to fail. This means less heat generated in its circuits, lower circuit cost and fewer components to fail, thus a longer life and cheaper price than plasma drive circuitry.
OLED is lighter than plasma and can be printed on sheets 1/3mm thick. Not only sheets of glass, but sheets of plastic. Plasma being a vacuum technology requires heavy, hard glass to keep atmospheric pressure from collapsing its vacuum cells. This means lower shipping costs and therefore lower prices for OLED. As fossil fuel runs out in the coming years, shipping costs will make up more and more of the price of finished goods, therefore weight will matter more and more as part of the total cost of a display.
OLED pixels can be made in any size, from the superfine dots of a laptop display to the large pixels of a 50" TV, and thus unlike plasma can be made in all sizes from cellphone to supergiant TV. The minimum size of plasma pixels limits its market to TVs.
OLED pixels retain their efficiency no matter the size, while plasma pixels get less efficient as their size is reduced, often dramatically so, due to wall losses which de-ionize the gas and which depends on its pixels' surface area / volume ratio. A cellphone OLED display can be just as bright and efficient as a 50" OLED-TV.
Though each of these differences between OLED and plasma may seem small, taken together they add up to a significant overall difference between displays, as the many people who have seen live OLED displays can attest.