What you don't know about OLED

Discussion in 'iPod touch' started by SnowLeopard2008, Oct 18, 2009.

  1. SnowLeopard2008 macrumors 604


    Jul 4, 2008
    Silicon Valley
    Most of you are awestruck by OLED screens and it's mind-blowing contrast ratios, deep blacks, wide color gamut and low power consumption. Most of you know OLED is an acronym for organic light emitting diode. In short, OLED screens use an organic material to replace the liquid crystal in LCD. But most of you don't know that OLED screens are similar to CSTN and plasma technologies in the aspect that it ghosts images. Here's why:

    CSTN is an early LCD technology that doesn't use the "active matrix" concept to send signals to individual pixels. It doesn't turn off individual transistors to display colors, but turn off entire rows and columns, which result in ghosting. There aren't transistors per pixel, but transistors per row/column. For example, in a matrix of 6 pixels:

    ---| |
    ---1 2

    To display a color on (1,2) it will shut off rows 1 and 3, and send a signal across column 1, but that results in (1,3) and (1,2) pixels getting the same signal. It's not a complete coordinate system, it operates on rows OR columns ONLY. It only has 5 transistors, 3 for each row and 2 for each column.

    TFT is what we currently use for LCDs. It's a step from CSTN in that it uses an active matrix to control individual pixels. No ghosting here. There are transistors per pixels. That's how you can address a specific color to a specific pixel. More expensive than CSTN though.

    OLED is what everyone is awestruck in devices such as the unreleased Creative Zii Egg and Microsoft's Zune HD. HDTVs are using OLED screens to reduce thickness. OLED's method of sending signals to pixels is exactly the same as CSTN.

    AMOLED is slowly gaining popularity and Samsung has introduced the first AMOLED phone to the US, with the Impression (AT&T) which as 3.2 WQVGA OLED screen in May 2009. AMOLED is the next step to OLED, and the extra AM- in front stands for active matrix. This is the true replacement to TFT technology, not OLED.

    It's similar to Intel's tick-tock roadmap. CSTN is the tick, TFT is the tock. OLED is the tick, AMOLED is the tock. Ticks are usually the brand new, first generation products. They aren't terrible, but there are some problems we haven't found answers to. It's ready for public release, but there are problems we have to address.
  2. 4DThinker macrumors 68020

    Mar 15, 2008
    The Zii doesn't use an OLED or AMOLED screen. Get your facts straight, man! Now I have to discard everything you said as unreliable. Oh my! :eek:
  3. Andy348 macrumors 6502

    May 18, 2009
    Lots of new stuff that I didn't know..

  4. iSpaghettiCat macrumors regular

    Sep 4, 2009
    Miami, FL
    OLED is horrible in the sunlight, which LCD makes up for in iPhones/iPod touches.

    Other than that, a great choice for a screen.

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