We report two optical structures for bottom‐emitting white OLED. We employed RGBW color system because of its high efficiency. for RGB‐subpixels, the cavity resonance was enhanced by dielectric mirror, and for W‐subpixel, the mirror was removed. Optical lengths were controlled by two different methods: by the thickness of dielectric filler on top of the mirror or by the angle of oblique emission. with both methods, we were able to fabricate AMOLEDs that exhibited color gamut exceeding 100% NTSC. More importantly, the transmission of white OLED through R/G/B color filters was significantly higher (up to 50%) than that of the conventional structure employing no mirror, even though the color gamut increased from ∼75% to ∼100%.

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.

Previously, we reported two optical structures for bottom‐emitting white OLED, exhibiting wide color gamut (> 100% NTSC) and high (> 40%) transmission through color filter. The panels employed RGBW color system for efficiency. The color shifts at oblique angles for the individual R, G, B, and R+G+B were maintained below Δu'v' < 0.02@ 60°. However, the colors produced by the combination of R/G/B subpixels and W subpixels exhibit large color shift when viewed at oblique angles because the luminance profiles, as a function of viewing angle, of the R/G/B which employ strong resonance, and the W which has weak resonance, are very different. In this report, we present a novel optical architecture for the W‐subpixel. The color shift for the W‐ subpixel was reduced from Δu'v' = 0.059 to 0.026 and the luminance profile was much closer to those of R/G/B subpixels. The efficiency of the W‐subpixel with the new structure was on the same level as that of the conventional, plain, weak‐resonance structure.

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.