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Ask HN: Do OLED displays only save energy with absolute black?

6 points by fortnum ↗ HN
It was always my understanding that OLED displays use less energy the darker the screen is. However I now came across some information that this is actually only true for absolute black (#000000).

Is that correct? Does #010101 use the same energy as #FFFFFF or do darker shades still use less energy?

6 comments

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wmf
I keep reading that OLEDs are more efficient but when you look at the final products, OLEDs (even with elaborate heatsinks) are dimmer than LED-backlit LCDs. There's definitely a lack of solid facts on this topic.
rolenthedeep
I have a galaxy note 10 (which I absolutely hate) but the AMOLED screen is far brighter and clearer than any backlit LCD I've ever used.
skavi
It took a while for OLED mobile displays to achieve the brightest we had with high end LCD mobile displays for years. There are still mobile LCDs just as bright as any OLED available (iPad Pro 12.9).
skavi
OLED displays are typically less efficient than a good LCD. Anyone who claims they are is perpetuating a myth likely rooted in the fact that OLED power scales with APL. They forget the high base cost of keeping the active matrix powered.
richajak
One question to android team members if any of them read this comment.

Why does the battery saver mode in Android Go require the phone to operate in dark mode? It claims that this will save the power. However it is not true in most cases as majority of low cost Android Go phones have IPS display, not AMOLED display.

What is the technical or business reasonings of this feature? a misunderstanding from teams within google? or the fact that dark mode can save power for both IPS and AMOLED displays?

kp195_
Mandatory not an expert disclaimer, but as far as I understand, OLED screens only light up individual pixels when needed (which means there's no backlight under the screen).

When displaying pure black (I guess that's only #000000, but I could be wrong), the pixels displaying it remain off, so those pixels would use no battery (since they're off)