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I made a small LED panel

(www.stavros.io)
154 points Brajeshwar | 2 comments | 09 Oct 25 15:31 UTC | HN request time: 0s | source
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Nevermark ◴[21 Oct 25 16:10 UTC] No.45657545[source]▶
For a second I thought this was about custom LED construction.

But apparently, LEDs require advanced processes unlikely to be available for makers, anytime in the near future.

However, Zinc sulfide phosphor mixed into epoxy can be used to make voltage activated luminescence. For some interesting guidance on "doping" for color, I present a 1953 patent:

> zinc" sulphide' activated by both copper ad manganese in accordance, with the present invention is strongly electroluminescent, the addition of. manganese to the copper-activated material resulting in a shift in the color of luminescence toward the red end of the spectrum. Thus, the materials of the invention, when excited by a fluctuating electric field, show colors of luminescence ranging from bluish-green through shades of bluish-white, pinkish-white and yellow to orange. [0]

Looks like some level of RGB was possible from the get go.

[0] https://patents.google.com/patent/US2743238A/en

replies(2): >>45657945 #>>45659681 #
jononor ◴[21 Oct 25 16:41 UTC] No.45657945[source]▶
Cool! What kind of voltage ranges are we talking, and how toxic is Zinc sulfide phosphor?
replies(1): >>45658108 #
1. Nevermark ◴[21 Oct 25 16:54 UTC] No.45658108[source]▶
Not that toxic, unless inhaled (take precautions) or ingested, or heated to high temperature, which produces a toxic gas.

Doping of course can change that.

May require 100+ V AC at 500-2000 Hz. So probably not the right element to implement 4k in! Or for an early education science experiment, unfortunately.

I don't know what the currents would be, proportions or dimensions of epoxy, or much else. Some more research would be required. But in terms of resistive heating creating gas: measure and be careful!

replies(1): >>45665644 #
2. jononor ◴[22 Oct 25 06:45 UTC] No.45665644[source]▶
Seems within reach of a hobbyist maker, at least the slightly unhinged kind (in the best meaning). Since considerable energy is needed but also avoiding excessive heating, integrating temperature measurement into the bulb might be prudent. Or at the very least having regulation on current+voltage. There might be risk of thermal runaway, if conductivity goes up when voltage is applied to the epoxy mixture.