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I didn't realize we even had a discrete LED tunable across the visible spectrum, let alone a Micro-LED array of them. Anybody know where I can buy one? I want to build a hyperspectral imager.
Do you mean hyperspectral imager (i.e., camera), or a hyperspectral display ?
Earlier quoted context omitted.
Do you mean hyperspectral imager (i.e., camera), or a hyperspectral display ?
An imager/camera: by illuminating a scene (or light box) solely with the tunable LED, sweeping it across the spectrum, and capturing it with an achromatic camera.
Btw, is that still reasonably effective if the scene has ambient illumination, but (in addition to shining each wavelength at it) you take a monochrome photo in only the ambient light and you subtract that out from all your other images?
That's not hugely surprising given that (I believe) LEDs have always shifted spectrum-wise a bit with drive current (well, mostly junction temperature, which can be a function of drive current.)
I guess that means they're strictly on/off devices, which seems furthered by this video from someone stopping by their booth:
https://youtu.be/f0c10q2S_PQ?t=107
You can clearly see some pretty shit dithering, so I guess they haven't figured out how to do PWM based brightness (or worse, PWM isn't possible at all?)
I guess that explains the odd fixation on pixel density that is easily 10x what your average high-dpi cell phone display has (if you consider each color to be its own pixel, ie ~250dpi x 3)
It seems like the challenge will be finding applications for something with no brightness control etc. Without that, it's useless even for a HUD display type widget.
In the meantime, if they made 5050-sized LEDs, they would probably print money...which would certainly be a good way to further development on developing brightness control.
A single wavelength can't reproduce all visible colors. These pixels are variable wavelength, but can only produce one at a time, so you'd still need at least 2 of these pixels to reproduce any visible color. The fundamental problem is that color space is 2D[1] (color + brightness is 3D, hence 3 subpixel on traditional displays), but monochromatic light has only 1 dimension to vary for color. [1]: https://en.wikipedi…
Earlier quoted context omitted.
If the refresh rate is high enough, a single LED could flip between multiple wavelengths to dither to non spectral colors.
Higher refresh/modulation rates imply higher power consumption. It’s already a trade-off in current display tech for mobile.
Earlier quoted context omitted.
An imager/camera: by illuminating a scene (or light box) solely with the tunable LED, sweeping it across the spectrum, and capturing it with an achromatic camera.
Ahh, that makes sense. Thanks! Btw, is that still reasonably effective if the scene has ambient illumination, but (in addition to shining each wavelength at it) you take a monochrome photo in only the ambient light and you subtract that out from all your other images?
A single wavelength can't reproduce all visible colors. These pixels are variable wavelength, but can only produce one at a time, so you'd still need at least 2 of these pixels to reproduce any visible color. The fundamental problem is that color space is 2D[1] (color + brightness is 3D, hence 3 subpixel on traditional displays), but monochromatic light has only 1 dimension to vary for color. [1]: https://en.wikipedi…
A lot of the article is focused on how this matters for the production side of things, since combining even 10 um wafer pieces from 3 different wafers is exceedingly time consuming, which I think is the more important part. Sure, the fact that each emitter can be tuned to "any colour" might be misleading, but even if you use rapid dithering like plasma displays did, and pin each emitter to one wavelength, you suddenly have a valid path to manufacturing insanely high density microLED displays! Hopefully this becomes viable soon, so I can buy a nice vivid and high contrast display without worrying about burn in.
A single wavelength can't reproduce all visible colors. These pixels are variable wavelength, but can only produce one at a time, so you'd still need at least 2 of these pixels to reproduce any visible color. The fundamental problem is that color space is 2D[1] (color + brightness is 3D, hence 3 subpixel on traditional displays), but monochromatic light has only 1 dimension to vary for color. [1]: https://en.wikipedi…
A single wavelength can't reproduce all visible colors. These pixels are variable wavelength, but can only produce one at a time, so you'd still need at least 2 of these pixels to reproduce any visible color. The fundamental problem is that color space is 2D[1] (color + brightness is 3D, hence 3 subpixel on traditional displays), but monochromatic light has only 1 dimension to vary for color. [1]: https://en.wikipedi…
Ha, yea, in particular these monochromatic pixels can't simply be white. Notably ctrl-f'ing for "white" gives zero results on this page. 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…