4 ms·

Yeh, the controllable opacity is really important to the utility of the device IMHO. I've yet to study the linked patent so can't say if that solves it but it'

by tb100 12y ago

Yeh, the controllable opacity is really important to the utility of the device IMHO. I've yet to study the linked patent so can't say if that solves it but it's not as simple as just a layer of LCD pixels, as they would not be in focus. It's sort of the same as the light-field generation problem - to generate images at arbitrary depths you need to control both the colour and direction of light rays. To generate sharp occlusions at arbitrary depths using a single 2D "masking" layer will require the layer selectively passing or blocking rays depending on their direction. The patent mentions variable diffraction gratings, which I suspect might be part of the solution to controllable opacity based on ray directions, but I don't know enough about optics really to say for sure.

tb100 12y ago
To expand upon what the problem is: imagine rays of light reflecting from a point going in all directions (essentially a sphere). A cone of those rays make it into your eye through the pupil. Putting a 2D layer just near to the eye means light from that one point is actually spread across a circle on that 2D layer, with diameter close to the pupil size (getting on for 4mm in indoor lighting). There is therefore significant overlap between the circles from distinct 3D points - so to block out just one of the points you need to selectively block the rays over that entire circle, but only those in the direction of the point we wish to block.