[dlcarrier]

Many phones have OLED screens that are capable of emitting only red light, if a software filter is applied, so there's no need to develop specialized hardware.

Chances are that the reason blue-light filtering glasses and night-time mode aren't working for you is the same reason that it doesn't work for anyone; studies show that the color temperature of light doesn't affect sleep or circadian rhythm:

https://www.bbc.com/future/article/20260407-the-blue-light-f...

https://www.manchester.ac.uk/about/news/researchers-discover...

A red-only filter for your phone would be great for preserving night vision, though.

If you want help sleeping, getting lots of light in the morning is greatly beneficial, especially full-spectrum light, including infrared. It's also helpful to avoid alcohol and caffeine, especially so later in the day.

[macrolet]

I agree, OLED can emit red light only. However, I am questioning whether that means there really is no need for red-only displays. As that mode on conventional displays (even on OLED) wastes pixels and is, more importantly, optional.

[ivanvoid]

Me drinking 4 cups of coffee and blaming phone light for my sleep problems.