Micro‐cavity design of bottom‐emitting AMOLED with white OLED and RGBW color filters for 100% color gamut

Abstract— Two optical structures used for a bottom‐emitting white organic light‐emitting diode (OLED) is reported. An RGBW color system was employed because of its high efficiency. For red, green, and blue (RGB) subpixels, the cavity resonance was enhanced by the use of a dielectric mirror, and for the white (W) subpixel, the mirror was removed. The optical length of the cavities was controlled by two different ways: by the thickness of the dielectric filter on top of the mirror or by the angle of oblique emission. With both methods, active‐matrix OLEDs (AMOLEDs) that reproduced a color gamut exceeding 100% of the NTSC (National Television System Committee) standard were fabricated. More importantly, the transmission of a white OLED through R/G/B color filters was significantly higher (up to 50%) than that of a conventional structure not employing a mirror, while at the same time as the color gamut increased from ～75 to ～100% NTSC.