Dye based circularly polarizing film for organic light emitting diodes

This invention relates to a dye based circularly polarizing film for organic light emitting diodes, including polarizing films and 1/4-wave sheets made of polyvinyl alcohol substrates, characterized in that: the polarizing films are color polarizing films, subjected to dyes with formulated high dichroic ratio, dyeing and stretching, such that the primary absorptive wavelength bandwidth is 80 to 120 nm within the range of absorptive wavelength between 500 and 640 nm, and the average light transmission for each sheet is 53 to 59% within the visible wavelength between 380 to 780 nm. Using the photopic vision phenomenon and the highest luminescence efficiency of green light among the three primary colors of OLED, color polarizing films that limit wavelengths (500 to 640 nm) are used to replace the non-reflective films that limit the entire wavelengths of visible light so as to obtain circularly polarizing films that do not have significant reduction in contrast, and increase external quantum efficiency by 25 to 30%. One face of the triacetyl cellulose films bonded to opposed sides of the polarizing films is an anti-dazzling or low-reflective film, or is a film having both functions to improve the contrast. This invention is able to improve luminescence efficiency, reduce power consumption and prolong the life cycle of OLED.