Electroluminescent device multilevel-drive chromaticity-shift compensation

A method for compensating for chromaticity shift of an organic light-emitting diode (OLED) emitter, comprising:

• a) providing the OLED emitter for receiving current and emitting light having a luminance and a chromaticity that both correspond to the density of the current;
• b) providing a drive circuit electrically connected to the OLED emitter for providing the current to the OLED emitter;
• c) receiving a designated luminance and selecting a chromaticity for the OLED emitter;
• d) selecting different black, first, second and third current densities based on the designated luminance and selected chromaticity, wherein
• i) at the selected black, first, second and third current densities the emitted light has respective, black, first, second and third luminances and respective, black, first, second and third chromaticities;
• ii) the respective luminance of each of the black, first, second and third current densities is colorimetrically distinct from the other three luminances, or the respective chromaticity of each of the black, first, second and third current densities is colorimetrically distinct from the other three chromaticities;
• and
• iii) the black luminance is less than a selected threshold of visibility, and the first, second and third luminances are greater than or equal to the selected threshold of visibility;
• e) calculating respective black, first, second and third percentages of a selected emission time using the designated luminance, the selected chromaticity, and the black, first, second and third luminances and chromaticities, wherein the sum of the black, first, second and third percentages is less than or equal to 100%;
• and
• f) providing the black, first, second and third percentages to the drive circuit to cause it to provide the black, first, second and third current densities to the OLED emitter for the black, first, second and third percentages, respectively, of the selected emission time, so that the integrated light output of the OLED emitter during the selected emission time has an output luminance and output chromaticity colorimetrically indistinct from the designated luminance and selected chromaticity, respectively, whereby the chromaticity shift of the OLED emitter is compensated.