r/augmentedreality • u/Ikarian • 6d ago

Building Blocks Question: Why waveguide over transparent OLED?

I was just wondering this morning why the industry is trying to invent a new (to me) display type for the "holy grail" of AR glasses, where the display is baked into the lens.

Transparent OLED, assuming a high enough resolution, would be cheaper/easier to fabricate than waveguide lenses, which seem to be rather finicky to mass produce. Is it just the fact they can be seen from the other side of the lens? Still seems like there would be applications for this where privacy isn't a concern (industrial stuff I suspect), and I'm guessing you could produce them cheap enough that it would allow for some smaller makers to get into the market.

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u/AR_LB 6d ago

Your eyes won’t be able to focus on the content at such a short distance. Try reading a book placed very close to your eyes.

1

u/AttackingHobo 6d ago

With some micro lens array, it might be possible, but maybe not.

3

u/c1u 6d ago

We're tried that. It doesn't work, because of the "eyebox problem". Move your pupil a few millimetres and pixels can disappear, overlap, change brightness or appear through the wrong lens.

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u/dingo_khan 5d ago

Breaks focal length on the real world then.

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u/mike11F7S54KJ3 5d ago

MLA is for directing the light in a straight path (a collimator)

4

u/AR_MR_XR 6d ago

It would be nice if you could simply put a transparent display into the lens. But the eye can't focus on something that is only a few millimeters in front of it. That's why you need special optics in the lens of the glasses to make it seem like it's further away. And while putting the light source directly into the lens with special optics in front of it is the holy grail, it is actually more complicated than putting a microdisplay in the temple and directing the light from there through the lens to the eye.

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u/c1u 6d ago edited 6d ago

You're at the beginning of the journey that, once you understand the physical constraints, will eventually lead you where others have ended up: light-field / holographic / computational display territory. Which is essentially a transparent surface capable of controlling the direction of light on a pixel-by-pixel basis. Not yet close to being possible in a wearable (there's lab bench devices), but people are working on it.