Comment by GuB-42
18 hours ago
It is all a compromise. 37 PPD is well under the standard for normal "good" eyesight (aka. "retina" in Apple marketing), which is 60 (aka. 1 arcminute).
Doing more with a narrower field of view is easy, it is even cheaper. Doing more with the same or better field of view means you need more pixels and more computing power to drive them, so more expensive, heavier hardware that gets hotter and with less battery life.
People at Meta consitered 37 PPD to be a good compromise, and I kind of agree.
The compromise is forced by the current cost of denser panels above anything else.
This is mostly driven by the fact that even in the current optimal case where they can maintain the number of defective pixels per panel, multiplying the number of pixels tanks bins. And then the follow on effects of longevity based on heat/brightness vs refresh rate, which improves generation over generation much faster than the former. The shit they're doing to print OLED panels out like an inkjet is exciting because once it gets good enough they will no longer need to write off the failures and will be able to selectively remove or overwrite the defects, which is not something that can usefully be done with other screen types.
The operation of switching the pixels themselves becomes increasingly inexpensive as they get smaller. For a long time the biggest barrier holding progress back was consistently and reliably being able to deliver smaller and more precise voltage swings. Almost all of the increased power consumption comes from either how much less backlight can make it through (which also becomes heat, this is already enough of a problem that certain display types include a separate extremely tiny panel that sits there and displays nothing so that they can be measured to adjust the voltage levels and termination resistances), or how bright each individual pixel can be. That's why the first 6? generations of OLED panels have so many wacky and (IMHO goddamn abhorrent) arrangements of R/G/B/W shapes and subpixels.
I was vaguely okay with this when they started doing things like including yellow/magenta subpixels on TVs but anything other than a square pixel aspect ratio for computers is so gross. Even if you're willing to ignore the fringing or outright cannot see it, I can still tell one generation of iPhone apart from another consistently in books.app with the smallest white on black text, the leading/trailing edges of the letters have different rainbows.
And displaying fractionally lower resolutions onto high dpi displays does not incur much of a cost at all, retina displays existing at all on mobile phones is proof of this.