LTPS - Page 12

DisplaySearch says that strong demand for Low Temperature Polysilicon (LTPS) based displays (LCDs and AMOLEDs) will drive rapid expansion of LTPS capacity. Spending on LTPS-equipment is expected to reach $2.4 billion in 2011 (and will decrease in 2012 and 2013).

DisplaySearch says that making AMOLEDs and high-end LCDs like the ones used in Apple's iPhone 4 is only currently possible with LTPS. In 2011, supply of both AMOLEDs and LTPS LCDs are forecast to be extremely tight. Leading panel makers are for the first time ever scaling LTPS technology to Gen-5.5 and larger substrates.

Two days ago we published a story saying that Chimei Innolux seems to be producing AMOLEDs again. We got just word (from a trusted source) that the company actually plans to scrap all OLED plans, and shift all LTPS capacity back to LCD.

This is strange as it seems the company is still recruiting AMOLED engineers and researchers. Perhaps they will shift the current Gen-3.5 OLED plant to LCD, but they still have plans to make AMOLEDs in the future (in the Gen-5.5 plant in Tainan, as stated in the company's presentation).

Back in December 2009, Chimei bought both TPO and CMO (and its CMEL OLED subsidiary). It wasn't clear what will happen to TPO and CMEL's OLED programs. CMEL had an active AMOLED program and even offered 7.6" panels, but production halted after the merger. TPO was said to develop small (3" and 4") AMOLEDs but had technical difficulties. Now we found out that Chimei Innolux is back into AMOLED production. In their 3Q 2010 financial results presentation they list their Fab status:

There are two OLED plants. The first is a Gen-3.5 (620x750mm) LTPS/OLED Plant in Jhunan, Taiwan targeting small/medium displays. There's also a Gen-5.5 (1,300x1,500) plant in Tainan (also in Taiwan). The Gen-5.5 line will produce OLEDs for monitors or TVs. The new OLEDs in the Gen-5.5 line will use an IGZO (InGaZnOx) TFT - a transparent amorphous oxide semiconductor.

A few days ago we reported about Samsung's new 4.5" WVGA (800x480) flexible AMOLED prototype, and today we have a couple of new photos and some more information.

The panel is made from LTPS TFTs, on a polyimide substrate. The OLED is top-emission, and is made by vapor deposition. The brightness is 250cd/m², and the contrast ratio is 100,000:1.

AU Optronics has acquired Toshiba Mobile Display's subsidiary, AFPD. AFPD had a Gen-4.5 LTPS plant. Now we hear that AUO plans to use a third of the lines in that plant for AMOLED production. This means 15,000 substrates a month in 2011. AUO's own Gen 3.5 factory (which will also go in line in 2011) will contribute 7,000 monthly substrates.

AUO 14-inch OLED prototype

Samsung are still keen on OLED TVs, which will be the "dominant technology in next-generation TVs by 2015". They will be the ultimate active-shutter 3D TVs. Samsung has plans to use an Gen 8 (2200mm x 2500mm sheet size) production line for the OLED TVs. There's no date or real commitment yet, but this will hopefully happen within the next few years.

Samsung 14-inch 3D OLED prototype

There are still some technical issues to overcome. For their upcoming 5.5-Gen plant, SMD plans to introduce LTPS TFTs using conventional excimer laser annealing (ELA). TFTs formed with this technology often exhibit variation in characteristics, and this method might prove difficult in larger line. SMD is also working on other technologies: improved ELA technology, sequential lateral solidification (SLS) and super grain silicon (SGS). The company is also developing oxide semiconductor TFTs.

AU Optronics has completed its acquisition of Toshiba Mobile Display's subsidiary, AFPD. This is part of AUO's strategic move into AMOLED production. AFPD has a Gen-4.5 LTPS plant, which can be used to produce OLED backplanes.

AUO 14-inch OLED prototype

AUO wants to quickly start making AMOLEDs, because of the enormous demand for small sized displays. AUO is also working on its own manufacturing line, which will go online in 2011.

Back in CES 2010, Samsung has shown a transparent-laptop prototype, with a 14" display. Today they are revealing the structure of that display. The screen has a 960x540 resolution, and a brightness of 200cd/m².

The top-emission OLED panel uses a LTPS TFT for its drive element. About 75% percent of each pixel is transparent, says Samsung, and this can be achieved by forming drive elements and organic EL elements (anode electrode, luminescent layer) on gate or source wiring. The OLED elements are made by using a metal stencil mask, and the cathode electrodes are made from a newly developed metal material.

Sony plans to sell an LCD plant that makes small-sized panels to Kyocera. Sony are moving away from LTPS (low-temperature polysilicon) and into a-Si (amorphous silicon) - they have just completed a deal to buy Seiko-Epson's small-size LCD operations that use the latter technology.

This is an interesting move by Sony, and might have implications on their OLED program, which shares some of the manufacturing process of LTPS LCDs.

AU Optronics is on track to start mass-producing small and medium AMOLED panels in 2011, and will start installing new production equipment in 3Q 2010. The OLED line will be remodeled from the company's idle 3.5G LTPS (low-temperature polysilicon) equipment. AUO has already announced plans to recuit new employees for the OLED production plant.

AUO 14-inch OLED prototype