AU Optronics Corp (AUO) made an announcement about its 32-inch LCD panel using oxide semiconductor TFTs as drive elements and exhibited the panel May 28, 2010, at SID 2010, an international conference on display technologies.
Though it was the final day of the conference, crowds of engineers flocked to the 32-inch panel, which is large enough for TVs. It probably was the most popular exhibit at the conference, attracting even more people than Sony's "rollable" OLED panel.
Though I found some unevenness in, for example, the image of a blue sky, there seemed to be no obvious defect such as a line defect.
"Though this must be the best sample, I was impressed by the high quality," said an engineer of a Japanese manufacturer.
Prototyped at 6th-generation production line
AUO prototyped the LCD panel at its sixth-generation LCD panel production line (the size of the glass substrate: 1,850 x 1,500mm). And it used amorphous IGZO (In-Ga-Zn-O) as a channel material, as in the case of Sony's 11.7-inch OLED panel.
The structure of the TFT is the coplanar type, which has a source/drain electrode on the side of the channel. The repeatability of the manufacturing process was enhanced by one hour of heat treatment at 250°C after forming the TFT array.
The size of the amorphous IGZO TFT is 47.4μm/5.5μm. Its carrier mobility, threshold voltage, subthreshold swing (S) value and on/off ratio are 5.16cm2/Vs, 0.5V, 0.38V/decade and 108, respectively.