The concept of a high-luminance light source based on luminescent conversion of LED light and optical concentration in a transparent phosphor is explained. Experiments on a realized light source show that a luminous flux of 8500 lm and a luminance of 500 cd/mm² can be attained using 56 pump LEDs at 330 W electrical input power. The measurement results are compared to optical simulations, showing that the experimental optical efficiency is slightly lower than expected. The present status enables applications like mid-segment digital projection using LED technology, whereas the concept is scalable to higher fluxes.

Abstract— A new polarized backlight system for liquid‐crystal displays (LCDs) is presented in which one linear polarization is preferentially coupled out by anisotropic scattering. The lightguide consists of a polymeric polarization‐dependent scattering film adhered to a transparent polymeric substrate. By changing the scattering power of the film, the polarized light outcoupling angles can be influenced and optimized to achieve a maximum outcoupling centered along the normal direction. The other linear polarization is mainly trapped in the lightguide and is shown to be recycled to enhance the overall light and/or energy efficiency. With a proper substrate choice, the achieved local contrast exceeds 14 over a 50‐mm range. A collimated light input further enhances the polarized contrast to well over 17.

The concept of an LED-based source with high lumen density is described. It contains a luminescent rod in which LED light is converted to light with a longer wavelength that is extracted from a small face of the rod. The fundamental limitations and possibilities are discussed, as well as the constituents needed. Results are shown for two realized high lumen density sources. A source with YAG:Ce as phosphor is extensively characterized and the results are compared to modeling results. A source with an optimized green emitting phosphor is used for projection. With 64 pump LEDs at 490 W peak electrical input and 50% duty cycle, a peak luminous flux of 18000 lm and a peak luminance of over 1000 cd/mm 2 is obtained, with an efficacy of 37 peak lm/W.

A new linearly polarized light emitting lightguide system is presented, consisting of a micro-structured anisotropic polymer film which is coated with an isotropic layer and adhered to a transparent polymeric substrate. With conventional edge-lighting of the lightguide very high polarized contrasts are realized, exceeding 100. A gain in efficiency can be achieved by recycling of the trapped light with the orthogonal polarization.