SEL Exceeds 1,000ppi With OLED

Semiconductor Energy Laboratory showed two new OLED displays at Display Innovations 2014 in Japan last month.

The first was a 2.8″ colour unit with 2560 x 1440 resolution – 1,049ppi! A c-axis aligned oxide semiconductor is used for the backplane. The gate driver is formed on a substrate and the source driver using a chip on film technique.

A foldable OLED display was also demonstrated – similar to the 5.2″ seen at SID (Display Monitor Vol 21 No 25), but in an 8.7″ size and with a touch function. The screen has 1920 x 1080 resolution and the backplane, gate driver and source drivers are constructed in the same way as the smaller OLED unit. It is less than 100µm thick, weighs 6g and has a 46% aperture ratio.

To realise the colour display on both models, SEL combined a colour filter and white (top-emission) OLED with a tandem structure.