https://hackaday.com/2016/01/19/a-digital-canvas-thats-hard-...
It matches the LCD lighting to the ambient light, so that it doesn’t have that “glowing screen” look, but instead looks like a flat picture.
Something else irrelevant to your question, but trés cool: https://hackaday.com/2019/08/17/great-artificial-daylight-vi...