Polarization conversion of polarized white light-emitting diodes with wire-grid polarizer

Abstract

The packaging structures of polarized white light-emitting diodes (PWLEDs) can be implemented with a reflective polarizer and a diffusive light source for enhancing transmittance. In this work, the polarization conversion mechanism of PWLEDs with wire-grid polarizers is studied. It was found that the Lambertian distribution function prevails for unpolarized 568 nm yellow emission of wavelength conversion, whereas for polarized blue light scattering, the Gaussian like scattering distribution gradually changes to Lambertian with increasing degree of scattering, owing to the enhanced surface scattering or phosphor concentration. The transverse magnetic polarized 474 nm blue light is preferentially scattered out with wider scatter, which is beneficial to the lower correlated color temperature (CCT) and high transmittance, and yields an increased degree of polarization and angular uniformity of radiance distribution.