Studies on different primaries for a nearly-ultimate gamut in a laser display

In using a laser light source, it becomes possible to realize an ultra-wide display gamut that approaches the human color vision limit. This paper introduces a method for extremely large gamut optimization for different primary numbers, and it offers a primary set that produces a nearly ultimate gamut. Considering display lightness, we calculated wavelength selection and lightness design of a display with 3-9 primaries in the CIELAB uniform color space (UCS) by optimizing the coverage of the optimal color gamut. Theoretically the maximum gamut area of a laser display with 3-12 primaries in the CIE xy and CIE u'v' chromaticity diagrams is also calculated for comparison. We recommend 6 primaries as a reasonable choice, since the coverage reaches 97.6% of the optimal color. Taking into account the luminance efficacy of radiation (LER) and feasible laser wavelengths in practice, we get a practical design of wavelengths and power for a laser projection display with 6 primaries, which covers 96.6% of the optimal color gamut.