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Comment by jkubicek | Hacker News Reader

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jkubicek·

> The Vision Pro comes in at a stunning 3,386 PPI.

Sweet jesus.

I know that PPD is the actual important measurement here, but still, a display with 3K PPI is outrageous.

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The DLP/LCD chips inside 4K video projectors have about the same pixel density.

Reflective displays like that are much simpler to make than an OLED.

Agree, but also the closer the screen gets to your eyeball the more it matters.

How so? The light coming into your eyes is taking the exact same physical path through your lens, and inside, as if the virtual display actually existed*. It's a physical requirement that the optics achieve this, for you to be able to see the image.

* Assuming the virtual display is virtually positioned at the focal plane of the lens, which is usually around 3m.

How does pixel density not matter the closer the display gets to your eye? What?

No idea what focal length has to do with anything, we're talking apparent pixel density which is directly related to screen distance.

> we're talking apparent pixel density which is directly related to screen distance.

If you ignore all the glass/plastic between the screen and your eye that's required to focus on it.

Simple: Pixels appear larger when they are closer to your eye.

https://news.stanford.edu/2020/10/22/future-vr-employ-new-ul...

So, given their comparison with iphone/65 inch TV we would need 10k PPI to get similar PPD.

I wonder if that's possible with todays technology

Edit: Seems like there are some news from last few years about samsung having 10k PPI displays

Seems like even 60 PPD in the central region would already be "good enough" for most.

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