Dark Mode – Does It Work?
The CE space is ripe with claims; Claims that ‘my product’ is the best, or ‘we have the largest market share, or our product has the best technology, and as folks who look at and catalog massive amounts of data, we understand that making such claims by citing data is not always quite ethical, as narrowing data sets is a way to bring up standing, and the fine print at the bottom of the page that defines the data is rarely read. That said, OLED displays have been making claims about how they save power when compared to LCD displays for many years and while the fine print is again a part of the answer to the validity question, from a logical standpoint, they should be less power hungry, at least for small panel OLED devices.
Small panel OLED displays use red and green phosphorescent OLED materials and a blue fluorescent OLED material to produce full color displays. Since these materials are self-emitting, when a segment of the display is black, those pixels are turned off, reducing power consumption. This differs from LCD displays, which generate light from an LED backlight, which passes through a liquid crystal ‘gate’ and on to a color filter that changes the white light to the three colors necessary to produce the millions of colors needed. However, when a section of the image is dark, the liquid crystal gate closes, blocking the light to the user, but the backlight itself remains on, and continues to consume power, so from a technical perspective, an OLED display should consume less power.
But what about real life? Does this really make that much of a difference to smartphones users, who would be the most affected by battery issues? While LCD display users are typically looking at images displayed on a white background, OLED users have been told that the best way to use their OLED smartphones effectively is to switch to ‘dark mode’, where the background is black, but some users are not used to ‘dark mode’ and have resisted the change, and likely have compromised much of the power saving benefits of OLED displays. This is particularly apparent with iPhone users, who have been exposed to OLED displays for only 4 years and less if you count the entire iPhone line, compared to Samsung users, who have been using phones with OLED screens since 2004.
There are some ground rules however before the question gets answered, as the brightness of the display, and by this we mean the user controlled brightness, has a great deal to do with the power consumption, regardless of the technology, so there is a material difference in results that would be generated in bright sunlight where the display would be turned up to full brightness as to those generated in relatively dark lighting situations. The answer also does not consider the consequences of high brightness and low brightness on color correctness and the phone’s ability to correct for these circumstances, but the data does include a number of different models (model years) of the same phone, and a number of different applications to see if the application itself influences the results. We show in the table below the averages to reduce the amount of data.
Small panel OLED displays use red and green phosphorescent OLED materials and a blue fluorescent OLED material to produce full color displays. Since these materials are self-emitting, when a segment of the display is black, those pixels are turned off, reducing power consumption. This differs from LCD displays, which generate light from an LED backlight, which passes through a liquid crystal ‘gate’ and on to a color filter that changes the white light to the three colors necessary to produce the millions of colors needed. However, when a section of the image is dark, the liquid crystal gate closes, blocking the light to the user, but the backlight itself remains on, and continues to consume power, so from a technical perspective, an OLED display should consume less power.
But what about real life? Does this really make that much of a difference to smartphones users, who would be the most affected by battery issues? While LCD display users are typically looking at images displayed on a white background, OLED users have been told that the best way to use their OLED smartphones effectively is to switch to ‘dark mode’, where the background is black, but some users are not used to ‘dark mode’ and have resisted the change, and likely have compromised much of the power saving benefits of OLED displays. This is particularly apparent with iPhone users, who have been exposed to OLED displays for only 4 years and less if you count the entire iPhone line, compared to Samsung users, who have been using phones with OLED screens since 2004.
There are some ground rules however before the question gets answered, as the brightness of the display, and by this we mean the user controlled brightness, has a great deal to do with the power consumption, regardless of the technology, so there is a material difference in results that would be generated in bright sunlight where the display would be turned up to full brightness as to those generated in relatively dark lighting situations. The answer also does not consider the consequences of high brightness and low brightness on color correctness and the phone’s ability to correct for these circumstances, but the data does include a number of different models (model years) of the same phone, and a number of different applications to see if the application itself influences the results. We show in the table below the averages to reduce the amount of data.
When looking at the averages for all four OLED smartphones, the data confirms that ‘dark mode’ is a power saver at all three brightness levels. In terms of the applications tested, one phone saw a 1% increase in power consumption at the lowest (30%) brightness level for three of the six applications tested. Other than that all phones saw a reduction in power which ranged from 1% to 69%, by switching to dark mode, in all brightness modes, for all applications. So with only the minor exceptions noted (this was from the oldest of the four phones) dark mode is a big benefit for those using OLED smartphones, and regardless of whether the OLED display inherently saves power over an LCD display at a variety of brightness levels, switching to dark mode will make sure you drain the least amount from your battery and have the longest time to use the phone between charges. Thanks to Purdue students for conducting the very detailed analysis.
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