Sung-Hoon Pieh

11.1: Invited Paper: 15inch RGBW Panel Using TwoStacked White OLED and Color Filter for LargeSized Display Applications

We have developed a twostacked white OLED based on bottomemission structure for largesized display. It consists of one unit emitting fluorescent blue and the other unit emitting phosphorescent yellow twodopant of red and green in a host layer. In order to improve the performance of the WOLED, we adopted new noncabazole compound as a hole transporting layer with high triplet energy level and akali—metal doped charge generation layer. In addition, we employed new greenish yellow dopant instead of previous green dopant to enhance the lifetime of the phosphorescent stack. The resulting device exhibits 61.3 cd/A of current efficiency, 30 lm/W of power efficiency, and 6.4 V of driving voltage of at 1000 nit where its CIE coordinate is 0.340, 0.334. Halflifetime T50 of the device is estimated more than 130,000 hrs at 1000 nit. We also fabricated 15inch HD panel employing the twostacked WOLED and color filter.

Dual-Plate OLED Display (DOD) Embedded With White OLED

White organic light-emitting diode (WOLED) with color filter adopting dual-plate OLED display (DOD) structure is proposed. In order to prevent outgassing from color filter and overcoat, the SiNx passivation film was deposited on the overcoat film. This structure does not show any defects after it has been kept over 500 hours of storage tests at 90 degC . By fabricating 1 stacked WOLED consisting of fluorescent blue layer/ phosphorescent red:green layer, luminance efficiency of 20 cd/A with CIEx = 0.29, CIEy = 0.37 was achieved.

Optimization of 2-Stack WOLED Structure With Consideration on Color Gamut and Power Consumption

We fabricated 2-stack white organic light-emitting diode (WOLED) structure with luminance efficiency of 27.4 cd/A and color point of (0.32, 0.29) where one unit device emitted blue color and the other emitted red and green colors. Comparing with other configurations possible for 2-stack WOLED, it was found that our structure had merits of higher color gamut and lower power consumption, in spite of low luminance efficiency. In our 2-stack structure, we found that the blue efficiency which determines the power consumption of panel was strongly dependent on the position of the blue emitting layer. Based on an optical simulation and a viewing-angle analysis, we proved that the change of the luminance of blue color came from the microcavity effect depending on the distances between anode and cathode and between blue emitting layer and cathode.