[sdiy] Controlling LED color shift over time for backlighting etc.

[brianw]

Interesting.

Is the Forward Voltage drop the only thing that affects color in LEDs?

Also, how long does it take for the Vf to change, and does it vary that much between components in the same batch? The advertisement mentions drift, which implies a long-term adjustment to keep individual components at the same current, but there is no mention of whether this is an effective way to match color between different components.

My understanding is that cheap LEDs do not match each other in color. LED manufacturers offer binning at an extra cost, where they test things like the wavelength and group specific components into narrow ranges. If you want to design a product with consistent LED color, you would need to start with higher-priced LED components that have been tested to match each other in output. Usually the part number for the LED has a suffix to indicate the bin, and the data sheet cites the nanometer wavelength range for that bin. The part is often available with no suffix, meaning that they skip the testing phase and pass the savings on for cheap products.

All things considered, I think it's important to know which factors have more effect on the color.

Brian

p.s. I have noticed that large LED displays often have hue shifts that are clearly visible between individual panels. My interpretation is that someone went cheap and didn't bother to manufacture all panels with narrowly-matched RGB colors. I suppose that could be corrected with color sensors and modifications of the image content, but it seems smarter to start with hardware that matches at the physical manufacturing stage.


On Feb 26, 2026, at 6:54 AM, drheqx wrote:
> Hi All,
>  If you are designing a system with LEDs as ambient lighting this device might offer a good solution to control color drift over time. The concept is very good and I am sure there are other ways to do this, but in the case of things like illuminated pads color drift and variation across a grid of pads can be very noticeable and this might be an effective way to control that drift. 
> 
> https://www.novosns.com/en/en_ambientlightingdriver-4546 <https://www.novosns.com/en/en_ambientlightingdriver-4546>
> 
> Mike

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