Yoon-Heung Tak

15-in. RGBW panel using two-stacked white OLED and color filters for large-sized display applications

— A 15-in. HD panel employing two-stacked WOLEDs and color filters for which the color gamut can be as high as 101.2% (CIE1976) and the power consumption is 5.22 W. The WOLEDs exhibit a current efficiency of 61.3 cd/A and a power efficiency of 30 lm/W at 1000 nits and their CIE coordinate is (0.340, 0.334). A 15-in. RGBW panel was investigated to verify the electrical and optical performance compared to that of a 15-in. RGB TV made by using FMM technology. The characteristics of the 15-in. RGBW panel are comparable to those of the 15-in. RGB panel. Color filters combined with WOLEDs is a possible patterning technology for large-sized OLED TV, which surpasses the limits of fine-metal-mask technology.

Novel technologies for commercialized 55-inch WRGB OLED TV

World’s first commercialized 55-inch WRGB OLED TV has been developed and launched recently. Large-sized OLED displays require novel technologies to realize mass production. We will introduce commercialized 55-inch WRGB OLED TV and its novel technologies including oxide TFT, WOLED, solid phase encapsulation, and compensation technologies.

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.

Dual‐plate OLED display (DOD) based on amorphous‐silicon (a‐Si) TFT backplane

— An improved AMOLED with an a-Si TFT backplane based on a unique structure is reported. The new structure is refered to as a dual-plate OLED display (DOD). While a top-emission OLED array is directly fabricated on a TFT backplane, the DOD consists of an upper OLED substrate and a lower TFT substrate, which are independently fabricated. Because the OLED substrate, which is fabricated through the process flow of bottom emission, is attached to the TFT substrate, the light is emitted in the opposite direction to the TFT backplane. The DOD enables the design of large-sized TFTs and a complicated pixel circuit. It can also not only achieve higher uniformity in luminance in large-sized displays due to the low electrical resistance of the common electrode, but also wider viewing angles.

3.2: Distinguished Paper: 15-inch XGA Dual-Plate OLED Display (DOD) Based on Amorphous Silicon (a-Si) TFT Backplane

We report the improved AMOLED with a-Si TFT backplane based on our unique structure. Our new structure use the encapsulation glass as a substrate for OLED which enable us to achieve the high aperture ratio, large TFT area, high luminescence uniformity, and low anode resistance.

3.3: Real Time Brightness Compensation for a-Si:H TFT Backplane AMOLED

a-Si:H TFT backplane based AMOLED with a real time brightness compensation circuit is presented. The brightness of AMOLED is automatically adjusted by the thermal sensor and temperature compensation system with feedback algorithm. By using this compensation circuit, the brightness differences over the temperature range −20 °C and 60 °C is reduced by 550cd/m2 to 30cd/m2.