**Author details**

60 Organic Light Emitting Devices

**Figure 17.** Photographs of the brightness obtained from the reference (*R*, left) and sample (*S*, right) WOLEDs (at 8 V) for *EL||* (a) and *EL┴* (b) under a rotating linear dichroic polarizer film. The white and blue arrows represent the transmission axes of the linear dichroic polarizer and the GBO polarizer, respectively. The active areas of the polarized WOLEDs were 1 mm × 1 mm. (It may be noted that the device *R* appears to be brighter than device *S* in Fig (b) because device *S* is more highly polarized along

We have fabricated flexible, polarized, and luminous OLEDs using a flexible GBO reflecting polarizer substrate. We have also described the fabrication and investigation of a polarized and luminous OLED and WOLED using a combination of a QWP retardation film and a GBO reflective polarizer. Polarized EL brightnesses of over 10,000 cd/m2 can be produced from the polarized OLED, with high peak efficiencies in excess of 10 cd/A, which are almost double those obtained from the polarized WOLED with only the GBO polarizer. The polarization direction of the EL light emitted from the polarized OLED corresponds to the passing axis of the GBO polarizer used. Furthermore, we have also shown that a high polarization ratio of greater than 35∼40 is possible over the whole emission brightness

the passing axis of the GBO polarizer, compared to that of device *R*.)

**3. Conclusions** 

Byoungchoo Park *Department of Electrophysics, Kwangwoon University, Seoul, Korea* 
