## 2 Testing Samples and Experimental Setup  
### Testing Samples  
To investigate the long-term reliability characteristics of OLED light source, total twelve OLED panels with four different types were analyzed in this. For each kind of OLED panel, three samples were tested. The photos and physical, electrical, and optical characteristics of each sample used in experiments are shown in Table 1. OLED panel type A, C, and D have different size and type B and C have same size but type B is flexible type OLED panel where all other OLED panel types are rigid panel. To investigate the characteristic changes due to the different shape but having the same emitting surface area, type A (square shape) and type C (rectangle shape) were selected and tested. To test long-term reliability differences due to the form factor type B (flexible) and type C (rigid) were selected and tested. Finally, to check the emitting surface area dependence, type C (small) and type D (large) were selected and tested, respectively. All OLED panels used in these experiments were obtained commercially in the market and manufactured by LG Display. These OLED panels are based on active matrix OLED technology with 2 stacks emission material layer structures. All OLED panels used in this study were manufactured using same materials and production process. To investigate the long-term reliability characteristics of OLED luminaires, total six OLED luminaries with two different kinds were analyzed. For each kind of OLED luminaire, three samples were tested as similar to the OLED panels. The photos and physical, electrical, and optical characteristics of each sample used in experiments are shown in Table 2. In the experiments, to investigate the dependences on the long-term reliability characteristics due to the operating power, OLED luminaires have similar optical and color characteristics including CCT and CRI but with different rated power (type E: 11 W, type F: 7 W) were tested for the analysis. Type E luminaire was obtained commercially in the market and manufactured by LG Display and type F luminaire manufactured by OCLESS. OLED panels from LG Display were used in the luminaire. \begin{table}
\begin{tabular}{c c c} \hline
**Type** & **Photo of OLED Panel** & **Characteristics** \\ \hline A & & - & Panel size: 100 mm \(\times\) 100 mm \\  & & - & Efficacy: 50 \(\mathrm{Im}/W\) \\  & & - & CCT: 3700 K, CRI: 90 \\  & & - & Operating current: 230 mA, voltage: 6 V \\  & & - & Model number: LL055 RS1-64P1-OY1 \\  & & - & - \\  & - & - & Panel size: 200 \(\mathrm{mm}\)\(\times\) 50 \(\mathrm{mm}\) \\  & & - & Efficacy: 50 \(\mathrm{Im}/W\) \\  & & - & CCT: 3700 K, CRI: 90 \\  & & - & Operating current: 245 mA, voltage 6 V \\  & & - & Flexible type panel \\  & & - & Model number: LL081 FR1-64P1-OY1 \\  & & - & Panel size: 200 \(\mathrm{mm}\)\(\times\) 50 \(\mathrm{mm}\) \\  & & - & CCT: 3700 K, CRI: 90 \\  & & - & Efficacy: 50 \(\mathrm{Im}/W\) \\  & & - & Operating current: 230 mA, voltage 6 V \\  & & - & Model number: LL081 RR1-64P1-OY1 \\  & & - & Panel size: 320 \(\mathrm{mm}\)\(\times\) 110 \(\mathrm{mm}\) \\  & & - & Efficacy: 40 \(\mathrm{Im}/W\) \\  & & - & CCT: 3700 K, CRI: 90 \\  & & - & Operating current: 800 mA, voltage 6 V \\  & & - & Model number: LL133 RR1-64P1-OY1 \\ \hline \end{tabular}
\end{table} 
Table 1: Organic light-emitting diode (OLED) panels used in the experiment.