Korean electronics manufacturers LG and Samsung each unveiled large screen 55-inch prototype OLED (Organic Light Emitting Diode) TVs at this year's CES in Las Vegas. Previously available only in super small screen sizes on phones and tablets, and in Sony's 11-inch HDTV, OLED is the latest stop in the evolution of television technology. OLED panels have excellent color saturation, image uniformity, brightness and contrast in an amazingly thin form factor and without many of the drawbacks of alternate TV technologies. To get an idea of why OLED is such a big deal requires you know a little bit about the various types of TV technology.
The two major types of TV technology today are plasma TV and LCD TV. Plasma TVs are generally superior to LCD TVs in black levels (contrast) and color saturation because each individual pixel lights up on its own. A plasma pixel emits its own light so it is called "self-emissive." The benefit of this technology is that it can produce excellent black levels (contrast) and motion resolution because the plasma phosphors can be fired up and turned off quickly on a per pixel basis. The drawback of such a set is that it tends to be fairly thick, requires a bit more power to run and it can't get quite as bright as an LCD TV.
LCD TV, on the other hand, requires a backlight in order to produce an image. LCD pixels are really nothing more than color filters that sit in front of a light source in order to create an image. Each individual LCD pixel can be opened or closed in order to pass or to block light. The backlight can be a standard fluorescent light known as CCFL (cold cathode fluorescent lamp) or it can be an array or strips of LEDs (light emitting diodes). LED-lit LCD TVs are also known as LED TVs. Because the LCD pixels transmit light through the panel instead of emitting their own light, LCD and LED TVs are referred to as "transmissive."
The benefits of LCD TV (and by extension LED TV) technology include higher brightness and lower power consumption, as well as the ability to create a thin cabinet by using a technique called "edge lighting." With edge-lighting, the LED lights can be located along one or more edges of the TV with a thin, low-profile light guide in the back of the TV cabinet focusing and diffusing the light in order to provide a relatively even light source for the whole screen. The drawback of LCD TV technology is that it can be difficult to get a uniform or even amount of backlighting on the whole screen (so you can get lighter blotches or bright spots), and motion can be blurred with some detail lost in fast-moving images. Also, because there is almost always some light bleed through the LCD pixels array, it's difficult for an LED or LCD TV to produce a truly black background for the image.
OLED pixels are self-emissive like plasma (each pixel generates its own light) so they can match or exceed plasma panels in black level performance, but they also maintain the slim panel thickness that we see on LCD panels. Because each pixel can be turned on and off quickly (LG claims a response rate as low as 0.1 microseconds), you can get excellent contrast and motion response from an imaging panel that may only be 2 or 3 millimeters thick (roughly the width of two or three business cards). Although Samsung hasn't published the physical specs of their Super OLED 55-inch set, LG claims that its 55-inch OLED panel at CES is just 4 mm (3/16 inch) thick and weighs under 17 pounds. From looking at both in person, it boggles the mind to think that such an impressive-looking image can come from something so thin. But there are no smoke and mirrors here.
Previous attempts at commercializing large OLED TVs have not been successful for a couple of reasons: manufacturing the panels is difficult and expensive; and up until recently the lifespan of the various OLED pixel colors (red, blue and green) has been uneven: typically the blue OLED pixels don't last as long as the red and green ones and this can lead to color shift or a shorter overall panel life (or both). Samsung claims they have solved the blue OLED phosphor aging problem (through they don't get into too many details why), so their OLED TV has a standard 1920x1080 pixel array of OLED pixels, each made up of a separate red, green and blue OLED sub-pixel elements. LG has worked around the problem by making their OLED TVs out of a dense array of white OLED elements (6 million of them!) with tiny red, green and blue filters in front of each OLED pixel in order to create a full 1080p color high definition image.
From looking at these sets close-up (and perhaps drooling ever so slightly), I must say the future is indeed looking bright for OLED TV.
