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

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

#21
post #20
post #16

That’s not true—just a very persistent myth. Your intuition is correct. Anandtech display reviews have actual measurements if you’re interested. See this chart: https://images.anandtech.com/doci/9394/luminance-curve.png From this article: https://www.anandtech.com/show/9394/analysing-amoled-power-e... What’s actually true that most people don’t expect is that OLED displays often use more power than LCD displays even…

> That’s not true; Which question are you referring to?

The title.

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

#22
post #13

Earlier quoted context omitted.

I found the following research paper that does seem to support your educated guess: Energy Aware Color Sets https://eprints.cs.univie.ac.at/4187/1/eg09_color.pdf

Could you point me in the right direction please? It does talk about OLED, but I couldn't find where it specifically referred to the question here.

My pleasure, hopefully this answers your questions, but if not, I’ll check back to see if you ask a follow up question.

From the “Applications and Results” section towards the end of the paper:

“Figure 9 documents the energy consumption of the three images of Figure 8. Energy consumption is measured according to our energy model from Equation 1, using various grid sizes. The most prominent observation is the substantial energy savings achieved by colors chosen according to our continuous optimization approach. Across the different grid resolutions, we save on average 41 percentage of energy compared to using ColorBrewer colors.”

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

#23
post #13

Earlier quoted context omitted.

Could you point me in the right direction please? It does talk about OLED, but I couldn't find where it specifically referred to the question here.

My pleasure, hopefully this answers your questions, but if not, I’ll check back to see if you ask a follow up question. From the “Applications and Results” section towards the end of the paper: “Figure 9 documents the energy consumption of the three images of Figure 8. Energy consumption is measured according to our energy model from Equation 1, using various grid sizes. The most prominent observation is the substant…

Thank you very much

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

#24
Complicating this is that OLED displays also strongly limit brightness in order to reduce wear, via an automatic brightness limiter. How they do it varies by manufacturer and you'll see different results if only part of the screen is bright versus if all of it is bright.

The only way to get good numbers would be to take several OLED TVs, a few LCD TVs, and measure their power usage at the outlet after calibrating them to be as close as possible, then running through several different test playbacks.

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

#26
post #16

That’s not true—just a very persistent myth. Your intuition is correct. Anandtech display reviews have actual measurements if you’re interested. See this chart: https://images.anandtech.com/doci/9394/luminance-curve.png From this article: https://www.anandtech.com/show/9394/analysing-amoled-power-e... What’s actually true that most people don’t expect is that OLED displays often use more power than LCD displays even…

Interesting article. I was surprised by how linear the luminance-power curves actually are.

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

#27
post #2

(Warning: I am not a display technology expert) I'm guessing it's a combination of yes and no. OLED screens save power on black colors because it can completely shut off the pixels responsible for illuminating that portion of the screen. If you have a slightly brighter color than pure black, the diode will turn on but not at full-brightness. Technically speaking, you probably stand to save the most power on a purely…

The problem is that I find it really hard to read. The contrast is too large for the eyes. Some background color and lighting makes reading more comfortable. Perfect black is good for video though

I'm reading this on an X1 Carbon with the OLED screen. The pure black is sometimes unsetting. Sometimes I'm adding brightness but the black stays black, on the IPS screen the black would've become gray which gives you visual feedback, but on OLED there is no such feedback and you think it doesn't work.

I switched everything to the dark mode, not because I like it, or want to save the battery, but because I afraid that the pixels will burn out.

When the laptop is booting it uses the full brightness, also some bootable Linux distros use the full brightness, as they lacking OLED-aware display drivers.

I also enabled auto hide for Ubuntu 22.04's taskbar, not sure for to do it for the topbar.

I use a very low brightness levels ~ 15%, otherwise the colors are too vivid for my taste.

I think dark mode on OLED somewhat saves the batery, but I'm not sure how much. I didn't measured it.

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

#29
post #16

That’s not true—just a very persistent myth. Your intuition is correct. Anandtech display reviews have actual measurements if you’re interested. See this chart: https://images.anandtech.com/doci/9394/luminance-curve.png From this article: https://www.anandtech.com/show/9394/analysing-amoled-power-e... What’s actually true that most people don’t expect is that OLED displays often use more power than LCD displays even…

Those charts are very old. Modern OLED are much better.
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