Sony Corp proved its potential to realize a resolution of 500ppi for OLED panels, whose resolutions are considered difficult to be enhanced, in a symposium at SID 2012.
The resolution of 500ppi is as high as those of the latest LCD panels. This time, the company applied OLED materials with a pixel pitch of 51μm (dot pitch: 17μm), which is equivalent to 500ppi, by using an offset printing method (thesis number: 68.4L).
Sony used the offset printing method to make a 270ppi (VGA) 3-inch OLED panel that it announced at SID 2011. It realizes full color display by applying red (R) and green (G) layers with the offset printing method and combining them with a blue (B) common vapor-deposited layer.
Sony did not disclose the technology used for applying the R and G layers at SID 2011. But, this time, the company announced that it is the offset printing method. Moreover, the company formed R and G layers whose line widths are 17μm by using the offset printing method and showed a picture of a pixel array that combines the R and G layers and the common vapor-deposited layer.
Sony also showed its latest OLED panel prototyped by using the offset printing method. Its screen size is 7.4 inches and larger than the screen size of the company's OLED panel announced one year ago (3 inches). It has a pixel count of 960 x 540 (q-HD) and a resolution of 150ppi. As for OLED materials, a high polymer material is used for its R and G layers and a low-molecular material for its B common vapor-deposited layer.