Yeah but he uses a huge parabolic mirror, which he places in the next room. He mentions fresnel lenses, but they are expensive, have color fringes, and depending on the focal length the whole light will also not be very flat.
The holy grail would be something that has the size of a picture frame, and you can slap below the ceiling, to fake a roof window.
If you combine a good fresnel lens with some clever mechanics or a micro mirror array light source, I wonder if you could even make the angle move over the day? Using fresnel lenses, you could also split it up into multiple cells, to make cooling easier. But I guess in the end there is a reason why the commercial system costs $30.000 and takes more than a foot of thickness.
The holy grail would be something that has the size of a picture frame, and you can slap below the ceiling, to fake a roof window.
If you combine a good fresnel lens with some clever mechanics or a micro mirror array light source, I wonder if you could even make the angle move over the day? Using fresnel lenses, you could also split it up into multiple cells, to make cooling easier. But I guess in the end there is a reason why the commercial system costs $30.000 and takes more than a foot of thickness.