Or if pixel density is high enough, adjacent pixels could display the colors to combine with no flickering. Unlike regular RGB subpixels, this would only be needed for areas where the color cannot be displayed by an individual pixel alone.
Yeah, and both techniques can be combined, which common with LCD screens, although it does sometimes lead to visible moving patterns when viewed close up.
There’s more flexibility with tunable wavelengths, though, since there will often be multiple solutions for what colors and intensities can be combined to create a particular photoreceptor response. By cycling through different solutions, I wonder if you could disrupt the brain’s ability to spot any patterns, so that it’s just a very faint noise that you mostly filter out.
Sure, but that’s assuming you need a higher rate than is already used for brightness. That’s a question I think can only be determined experimentally by putting real human eyes on it, although I think you could do the experiment with traditional RGB LEDs. But the other question is whether the wavelength tuning can be changed at the same rate as intensity.