Roll up! Roll up! Sony develops super-flexible OLED screen
By Darren Quick
May 26, 2010
The miniaturization of electronic components has seen mobile devices shrink to the point where screen size is a major limiting factor. That could be set to change with Sony announcing it has developed a super-flexible full color OLED display which can be repeatedly wrapped around a thin cylinder while still producing moving images. Could we soon see mobile phones with pencil form factors and roll out displays?
The new display was possible thanks to the development of integration technologies of Organic Thin-Film Transistors (OTFTs) and OLEDs on an ultra-thin 20-micrometer thick flexible substrate. A flexible on-panel gate-driver circuit with OTFTs and soft organic insulators allowed Sony to get rid of the conventional rigid driver integrated circuit (IC) chips that would impede the rolling up of a display.
By combining these technologies, Sony was able to demonstrate the world’s first OLED panel which is capable of producing moving images while being repeatedly rolled-up and unrolled around a cylinder with a radius of 4mm. Even after 1000 cycles of repeatedly rolling-up and stretching the display there was no clear degradation in the display’s ability to reproduce moving images.
The rollable OTFT-driven OLED display measures 4.1-inches wide and just 80 micrometers thick. It has a resolution of 432 x 240 pixels at 121 pixels per inch (ppi), which Sony says makes it the world’s highest-resolution OTFT-driven OLED display. It can produce 16.8 million colors with a peak brightness of over 100 cd/m2 peak and contrast ratio of greater than 1000:1.
Because the organic materials used to create the display are easily dissolved in common solvents Sony will proceed with the development of a solution/print based process to manufacture such display devices. This process requires fewer steps, and consumes materials and energy more efficiently, resulting in a smaller environmental impact compared to the conventional high temperature vacuum semiconductor process used for inorganic, silicon materials.
Sony says it will continue to improve the performance and reliability of its flexible organic displays as it expects the technology to yield thin, light-weight, durable and mobile devices with previously unachievable form factors.