Enhancing efficacy in laser projection by four wavelength combination

Abstract In this paper we present a novel study about the combination of four laser wavelengths in order to maximize both color gamut and efficacy to produce the color white. Firstly, an analytic method to calculate efficacy as a function of both four laser wavelengths and four laser powers is derived. Secondly, we provide a new way to present the results by providing the diagram efficacy vs. color gamut area that summarizes the performance of any wavelength combination for projection purposes. The results indicate that the maximal efficacy for the D65 white is only achievable by using a suitable combination of both laser power ratios and wavelengths.