US Patent 7977872 High-color-temperature tandem white OLED

An OLED device having two spaced electrodes including: first, second, and third light-emitting units disposed between the electrodes, the first light-emitting unit produces light that has multiple peaks at wavelengths longer than 500 nm and substantially no emission at wavelengths shorter than 480 nm, and the second and third light-emitting units produce light that has substantial emission at wavelengths shorter than 500 nm; intermediate connectors respectively disposed between the first and second light-emitting units, and between the second and third light-emitting units; and wherein the OLED device emits light with a color temperature greater than 7,000K.