alt Hacker News> The more I think about this, the less sense it makes
And yet, it’s the fundamental technology enabling always on phone and smartwatch displays
The intent of this is to reduce the time that the CPU, GPU, and display controller is in an active state (as well as small reductions in power of components in between those stages).
for small screen sizes and low information density displays, like a watch that updates every second this makes a lot of sense
it would make a lot of sense in situations where the average light generating energy is substantially smaller:
pretend you are a single pixel on a screen (laptop, TV) which emits photons in a large cone of steradians, of which a viewer's pupil makes up a tiny pencil ray; 99.99% of the light just misses an observer's pupils. in this case this technology seems to offer few benefits, since the energy consumed by the link (generating a clock and transmitting data over wires) is dwarfed by the energy consumed in generating all this light (which mostly misses human eye pupils)!
Now consider smart glasses / HUD's; the display designer knows the approximate position of the viewer's eyes. The optical train can be designed so that a significantly larger fraction of generated photons arrive on the retina. Indeed XReal or NReal's line of smart glasses consume about 0.5 W! In such a scenario the links energy consumption becomes a sizable proportion of the energy consumption; hence having a low energy state that still presents content but updates less frequently makes sense.
One would have expected smart glasses to already outcompete smartphones and laptops, just by prolonged battery life, or conversely, splitting the difference in energy saved, one could keep half of the energy saved (doubling battery life) while allocating the other half of the energy for more intensive calculations (GPU, CPU etc.).