Sang-yeol Kim

A 3.0-in. 308-ppi WVGA AMOLED with a top-emission white OLED and color filter

— A 3.0-in. 308-ppi WVGA top-emission AMOLED display with a white OLED and color filters, driven by LTPS TFTs demonstrating a color gamut of >90% and a Δ(u′,v′) of <0.02 is reported. A white-emission source with a unique device structure was developed using all fluorescent materials and yielded efficiencies of 8.45% and 16 cd/A at 4000 nits with CIE color coordinates of (0.30, 0.32).

54.4: Highly Efficient and Wide Color Gamut White OLED Architecture for Display Application

Highly efficient WOLEDs, with the efficiencies of 19 cd/A, 16 cd/A, and 33 cd/A and CIE color coordinates of (0.25, 0.35), (0.30, 0.32), and (0.30, 0.32) respectively, have been developed. The broad white emitting TE-WOLEDs for high resolution display have been realized by controlling the microcavity between the cathode and anode. 96 % of NTSCx,y ratio was achieved from the TE-WOLED with the optical path control layer (OPCL) and new green color filter (CF).

10.3: 4.0 Inch Organic Thin Film Transistor (OTFT) Based Active Matrix Organic Light Emitting Diode (AMOLED) Display

We have developed a 4.0 inch pentacene organic thin-film transistors (OTFTs) based active matrix organic light-emitting diode (AMOLED) display. To achieve bright and uniform displays, we have investigated several process issues unique to OTFT-based OLEDs. A bottom contact structure was used to fabricate the pentacene TFT backplane. Fine metal masking (FMM), laser ablation technique (LAT), and polyvinyl alcohol based patterning method were used to isolate the pentacene active layer. The low processing temperature (maximum 150°C) may allow the use of polymeric substrates and lower cost processing. Uniform TFT performance is achieved with reasonably good mobility and on/off ratio. The initial OLED display performance is also presented.

P-214: Ultra Thin-Film Encapsulation for AMOLED Displays

A 5.4-inch AMOLED display was prepared using the combination of ultra thin film encapsulation steps with alternative organic and inorganic hybrid multi-layers. Organic layers for smoothing and improved adhesion were prepared by polyurea condensation with vapor deposition polymerization. Al2O3 inorganic layers were sequentially deposited on organic layers by sputtering. All processes were performed at room temperature. After optimization of the organic and inorganic layer deposition process, device operating lifetime performance was over 85%, as compared with glass encapsulation, and the transmittance of thin film multilayered structure was over 90% in the visible region.

P-16: Integration of the 4.5″ Active Matrix Organic Light-emitting Display with Organic Transistors

We developed an active matrix organic light-emitting display(OLED) on a glass using two organic thin-film transistors(OTFTs) and a capacitor in a pixel. The OTFTs has bottom contact structure with a unique gate insulator and pentacene for the active layer. The width and length of the switching OTFT is 500 μm and 10 μm respectively and the driving OTFT has 900 μm channel width with the same channel length. The characteristics of the OTFTs were examined by test cells around display area and generated images on the panel. The mobility was 0.3 cm2V−1S−1 and the current on/off ratio was 106. The uniformity and stability were confirmed through still and moving images on the panel. The organic light-emitting layers were fabricated by shadow mask process and color fluorescence materials were used for the emitting layers. The resolution of the panel is 64×RGB×64 in 4.5 inch diagonal and the aperture ratio was 25%.

P-228: Degradation of White Light Emitting OLEDs

We firstly report the degradation analysis of multilayer structured WOLED by using spectroscopic and microscopic analytical methods. Our analytical results demonstrated that the interface between cathode and electron-transporting layer is responsible for the intrinsic long-term degradation of WOLEDs.

Organic thin-film transistor arrays for active-matrix organic light emitting diode

We developed an active matrix organic light-emitting diodes (AMOLEDs) on a glass using two organic thin-film transistors (OTFTs) and a capacitor in a pixel. OTFTs switching-arrays with 64 scan lines and 64 (RGB) data lines were designed and fabricated to drive OLED arrays. In this study, OTFT devices have bottom contact structures with an ink-jet printed polymer semiconductor and an organic insulator as a gate dielectric. The width and length of the switching OTFT is 500μm and 10μm, respectively and the driving OTFT has 900μm channel width with the same channel length. The characteristics of the OTFTs were examined using test cells around display area. On/off ratio, mobility, on-current of switching OTFT and on-current of driving OTFT were 106, 0.1 cm2/V-sec, order of 8μA and over 70 μA respectively. These properties were enough to drive the AMOLEDs over 60 Hz frame rate. AMOLEDs composed of the OTFT switching arrays and OLEDs made by deposition of small molecule materials were fabricated and driven to make moving images, successfully.

Integration of 4.5” active matrix organic light‐emitting display with organic transistors

Abstract We developed a 4.5” 192x64 active matrix organic light‐emitting diode display on a glass using organic thin‐film transistor (OTFT) switching‐arrays with two transistors and a capacitor in each sub‐pixel. The OTFTs has bottom contact structure with a unique gate insulator and pentacene for the active layer. The width and length of the switching OTFT is 800 ? and 10? respectively and the driving OTFT has 1200? channel width with the same channel length. On/off ratio, mobility, on‐current of switching OTFT and on‐current of driving OTFT were 106,0.3∼0.5 cm2/V•sec, order of 10 μA and over 100 μA, respectively. AMOLEDs composed of the OTFT switching arrays and OLEDs made using vacuum deposition method were fabricated and driven to make moving images, successfully.