Oxide TFT

Semiconductor Energy Laboratory (SEL) demonstrated two new OLED display prototypes, both based on the company's proprietary CAAC-IGZO (c-axis aligned crystalline In-Ga-Zn-O) backplane material.

First up is the world's smallest 8K display, a 8.3" OLED (1058 PPI) with a resolution of 7680x4320. The panel is based on a white OLED with color filter architecture.

China-based display maker CSOT held a ceremony yesterday as it started construction on its upcoming T7 large-area display production fab. The T7 fab, which has a total cost of around 42.7 billion Yuan ($6.15 billion USD), will produce both LCD and OLED displays.

Total capacity in the T7 line will be 105,000 monthly substrates (according to our information, the OLED capacity will be 20,000 monthly substrates). The T7 OLED line will use IGZO backplanes and inkjet printing deposition. CSOT's plan is to start production by the end of 2020 - with real mass production starting in 2021.

IHS posted an interesting article which details a new backplane technology that Apple is developing. So-called Low-Temperature Polycrystalline Oxide (LTPO) combines both LTPS TFTs and Oxide TFTs (IGZO, Indium Gallium Zinc Oxide). LTPO is applicable for both OLED and LCD displays.

In LTPO, the switching circuits are using LTPS while the driving TFTs will use IGZO materials. This could lead to a power saving of around 5-15% compared to the currently-used LTPS backplanes. The main drawback of LTPO, however, is that the IGZO TFTs are larger and so the display density may be compromised. IHS says that Apple may introduce this into future iPhones - but it also says that LTPO will be limited to low-density displays at first which is a bit confusing.

TCL announced that its CSoT Subsidiary (China Star, also known as Shenzhen Huaxing Photoelectric Technology) plans to establish an LCD+OLED TV fab in Shenzhen, China. The new fab will have a monthly capacity of 90,000 substrate - and will produce 65- and 75-inch OLED TVs in addition to 65-, 75- and 75-inch 8K LCDs, all on Oxide-TFT backplanes. The line will begin operation in 2021.

The fab will apparently have two different production lines. The LCD line will be a 11-Gen line (3370x2940 mm) while the OLED Line will use smaller 8.5-Gen substrates (although this is not clear, CSoT may aim to use the 11-Gen substrates for OLED deposition too, perhaps cutting these large substrates before the OLED processing. Total investment in this new fab will be 42.6 billion Yuan (or about $6.7 billion USD).