Step by step the OLED industry has established that active-matrix OLED (AMOLED) displays work, that they have a long enough lifetime for many small-display applications, and that they’re manufacturable in volume. What they have not yet demonstrated is if the manufacturing processes are scalable to the extent TFT-LCD processes are. Nor have they demonstrated manufacturing with the 90-plus-percent yields common for small TFT-LCDs.

Ken Werner
Senior Analyst and Editor

But Douglas Park, president of the CMO subsidiary CMEL, said today he expects his company’s manufacturing yields for AMOLED panels to rise to 85% by the end of this year, up from 70% now. A second production line is under construction and should become operational in October. Total output of the two lines should reach 800,000 units (2.8-inch display equivalents) per month. The company is also considering the installation of a new Gen 5 or 5.5 manufacturing line, said Park, but no timeline was announced.

Higher yields and larger substrates are what AMOLED technology needs if it’s to narrow the price gap with TFT-LCDs. It also needs applications that leverage the technology’s unique properties - such as flexibililty and extreme thinness - so it can do more than make the case that AMOLED is just a superior replacement for TFT-LCDs.

Several applications of that sort were shown at the SID show in Los Angeles in late May, and a disproportionate number of them were in the expansive Samsung SDI booth.

You know that 2-inch photograph you have to get when you obtain a new passport or a business travel visa? SDI, together with Bundes Druckerei, have developed a 2-inch QVGA AMOLED substitute. The AMOLED, SDI says, is thin enough (300µm) to be put in a passport using a low-temperature lamination technique. With thin-film encapsulation, the display is bendable. Can the display be too thin? Not when it’s going into something you are going to bend and perhaps even sit on. As SDI put it, "The thinner, the robuster."

SDI also showed the world’s first foldable AMOLED. Two AMOLEDs are overlapped using an optical wetting process that avoids a visible seam when the display is open. When folded the package is about the size of a cell phone; when unfolded the display is 5.4 inches on the diagonal and has 480×272 pixels.

An all-in-one AMOLED module called the "Onebody" included a 2.22-inch 240×320 cell-phone main display and a 1.04-inch 176×64 sub-display in a single 1.26-mm-thick module. Another version of the main/sub idea was a 2.8-inch 240×400 main display with a 2.4-inch 240×320 sub-display next to it. Among the many possibilities would be to use one display for a soft keyboard on a mobile handset, and the other for traditional functions simultaneously.

Finally, SDI showed a 5-inch QVGA transparent AMOLED with typical AMOLED luminance and color gamut. (See photo.) I’m not quite sure what this is good for, but, as NEC’s Robert Dunhouse said during the show, customers are creative. Besides, the display looked great.