Re:Polychromatic Pixels
by etrautmann on Thursday July 18, 2024 @03:35PM
(#40998975)
It would be interesting to plot all of the achievable colors of this LED on the chromaticity diagram. Presumably it'd be some sort of circle/ellipse around white but might have some dropouts in certain parts of the spectrum?
Re:Polychromatic Pixels
by formerly_proven on Thursday July 18, 2024 @04:07PM
(#40999228)
Pure wavelengths are on the horseshoe-shaped outline of the CIE 1931 space. The straight line connecting the ends of the horseshoe is the line of purples, which also isn't monochromatic.
https://en.wikipedia.org/wiki/Chromaticity#/media/File:Planc...
Presumably they wouldn't need to do a pixel-to-pixel mapping, but could account for the wavelengths of neighbouring pixels to produce a more faithful colour reproduction at an effectively lower resolution.
It's going to be the spectral locus.
Re:Polychromatic Pixels
by daniel_reetz on Thursday July 18, 2024 @05:27PM
(#40999929)
Don't forget about bond wires that need to be run to each die and/or connected to a backplane.
Re:Polychromatic Pixels
by ricardobeat on Thursday July 18, 2024 @06:00PM
(#41000168)
Doesn't the fact they have successfully demonstrated displays at 2000, 5000 and 10000 DPI alleviate those concerns a little bit?
It's not really meant as a concern, more a supporting argument: If every subpixel is identical, you can use simpler wiring patterns.
The subpixels don't need bonding wires, they have dedicated connections just like any transistor on a regular IC.
The key to this is using the same process to get all the colors. For separate R,G,B pixels you need 3 different processes and can't build them on the same chip, you need to assemble them - that's what allows the vast improvement in pixel density.
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.