The question is not whether three RGB lights with variable intensity and backlight can produce yellow. They obviously can. The question is whether or not adding a fourth light in the way Sharp does produces a better picture. The newest large-screen RBG LCD TVs look better than the first RPTVs which came out but it is still the same RBG. The goal is a better perceived picture, not satisfying purists' theoretic ideals.
Anyone who has ever painted knows that you can use the three basic colors and white to get to everything, but I have known any number of painters over the years and none of them starts a painting with only four tubes of paint in the box.
Anyone who has ever painted knows that you can use the three basic colors and white to get to everything, but I have known any number of painters over the years and none of them starts a painting with only four tubes of paint in the box.