Polychromatic Pixels

Relatedly, the page talks a lot about pixel density, but this confused me: if you swap each R, G, or B LED with an adjustable LED, you naively get a one-time 3x boost in pixel area density, which is a one-time sqrt(3)=1.73x boost in linear resolution. So I think density is really a red herring.

But they also mention mass transfer ("positioning of the red, green and blue chips to form a full-colour pixel") which plausibly is a much bigger effect: If you replace a process that needs to delicately interweave 3 distinct parts with one that lays down a grid of identical (but individually controllable) parts, you potentially get a much bigger manufacturing efficiency improvement that could go way beyond 3x. I think that's probably the better sales pitch.

Human eyes have three different color receptors, each tuned for it's own frequency, so it's already 3d. However, apart from human perception, color, just like sound, can have any combinations of frequencies (when you split the signal with Fourier transform), and may animals do have more receptors than us.

Dynamic resolution / subpixel rendering. Retina looks really good already, not sure if the effect would be relevant or interesting but it might open up something new

Citation needed. The article doesn't say anything about how the colors are generated, and whether they can only produce one wavelength at a time.

Assuming they are indeed restricted to spectral colors, dithering could be used to increase the number of colors further. However, dithering needs at least 8 colors to cover the entire color space: red, green, blue, cyan, magenta, yellow, white, black. And two of those can't be produced using monochromatic light -- magenta and white. This would be a major problem.

I think about it from the CIE "triangle" where wavelength traces the outer edge, or even the Lab (Luminance a-green/red b-yellow/blue) color space since it's more uniform in perceivable SDR color difference (dE).

https://luminusdevices.zendesk.com/hc/article_attachments/44...

One key realization is that although 1 sub-pixel can't cover the gamut of sRGB (or Rec2020), but only 2 with wavelength and brightness control rather than 3 RGB. Realistically, this allows something like super-resolution because your blue (and red) visual resolution is much less than your green (eg 10-30pix/deg rather than ~60ppd). However, your eye's sensitivity off their XYZ peaks are less and perceived brightness would fall.

I guess what I'm saying is that a lot of the assumptions baked into displays have to be questioned and worked out for these kinds of pixels to get their full benefit.

If you take the "no subpixels" claim out of the article, this technology still seems useful for higher DPI and easier manufacture.

Note that even if we restrict our attention to the max-saturation curve, these pixels can't produce shades of purple/magneta (unless, as you say, they use temporal dithering or some other trick).

Even if these could produce just three wavelengths, if you can pulse them fast enough and accurately, the effect would be that color reproduction is accurate (on average over a short time period)

I probably missed something in the article, though I do see ex. desaturated yellow in the photographs so I'm not sure this is accurate.

If you can't control saturation, I'm not sure dithering won't help, I don't see how you'd approximate a less saturated color from a more saturated color.

HSL is extremely misleading, it's a crude approximation for 1970s computing constraints. An analogy I've used previously is think of there being a "pure" pigment, where saturation is at peak, mixing in dark/light (changing the lightness) changes the purity of the pigment, causing it to lose saturation.

I doubt they can. Probably the process only works (or yields) small pieces, otherwise they'd be doing exactly what you suggest.

I also notice that their blues look terrible in the provided images. Which will be a problem. I don't think they get much past 490nm or so? That would also explain why they don't talk at all about phosphors, which seem like a natural complement to this tech... I don't think they can actually pump them. Which is disappointing :(

I instead understand that this is false. Available MicroLED screens (TVs) are in fact brighter than normal screens.

The issue with MicroLED is instead that they are extremely expensive to produce, as the article points out, due to the required mass transfer. Polychromatic LEDs would simplify this process greatly.

I image these displays could have color sensors attached to self-calibrate.

Or the variability is low and all you need is very precise voltages.

I think the first versions will be RGB displays with fixed colors, just no longer needing mass transfer. You could use tens of subpixels per pixel, reducing all worries about color resolution.

Make these into e.g. 1x1cm mini displays and mass transfer those into any desired display size.

There are ways to compensate for perceptual drift like modern LCD drivers, but unless the technology addresses the same burn-in issues with OLED it won't matter how great it looks.

You may want to look at how DMD drivers handled the color-wheel shutter timing to increase perceptual color quality. There are always a few tricks people can try to improve the look at the cost of lower frame rates. =)

Black levels would be determined more by reflectivity of the display than illumination.

Nvidia is both a blessing and a curse in many ways for standardization... =3

The human eye can't distinguish light spectra producing identical tristimulus values. Thus for display purposes [1], color can be perfectly represented by 3 scalars.

[1] lighting is where the exact spectrum matters, c.f. color rendering index

That's because the points on outer edge of CIE are pure wavelengths and you can get to any point inside by interpolating between two of them.