Slashdot Mirror
Video Projector on a Chip?
Stile 65 writes "Cornell researchers have made a 0.2mm-squared mirror mounted on carbon fibers that can oscillate at 2.5KHz, 'caus[ing] a laser beam to scan across a range of up to 180 degrees.' These can be mounted on a chip, and in combination with lasers, arrays of such mirrors on a chip can be made into a video projector. From the article: ''"It would be an incredibly cheap display," [Cornell grad student Shahyaan] Desai said. And the entire device would be small enough to build into a cell phone to project an image on a wall."' This display is made possible because of the innovative use of carbon fiber instead of silicon in MEMS. Unlike a standard DMD, this type of device would have one mirror per scanline, not one mirror per pixel, allowing the chip to be much smaller."
"It would be an incredibly cheap display," [Cornell grad student Shahyaan] Desai said. And the entire device would be small enough to build into a cell phone to project an image on a wall." This is just what we need. There's already people on the subway that use the speaker on their phone to subject everyone to their poor taste in music. Now we'll have people subjecting everyone to their poor taste in television as well.
The theory of relativity doesn't work right in Arkansas.
You still need a light source -- in this case, lasers. Yes, I know you can get red lasers dirt cheap, but any thing else is very expensive. A laser light source operates at a defined wavelength, and although you cannot easily generate the full spectrum of colors from a single laser. You can get a red, green, and blue laser to potentially mix to generate the full visible spectrum, but the green and especially the blue lasers are very expensive. Also, size does matter -- it is difficult to pack bright light power sources into a small space, like say a cell phone. The techology leap forward here is great in principle, but the phrase "Video projector on a chip" is incorrect, since only the mirrors are on the chip, not the light source.
I'd like to see if a regular, broadcast TV could be designed to use one of these and project on my wall, and how well it would rival current home theater setup.
-uso.
What you hear in the ear, preach from the rooftop Matthew 10.27b
I was thinking about a project like this when I was a wee little kid. Back then I though that you could send the scan thru an oscillating crystal, but it never would have worked out. Oh and the fact that a blue laser (or full color?) was in the 10's of thousands of dollars.
:)
But more importantly was how to solve the Vertical scan issue?
Simple, A hexagonal mirrored surface (add more surfaces, get a higher refresh rate).
This way you only need the one horizontal high-speed scan, and a 'relatively' slow Vertical scan.
Apply it to movie theaters... up the wattage of the lasers used and the number of surfaces on the vertical drum. Take that IMAX!
Well, I'm sure it will never happen. but when I was 16, boy could I dream
we could get the scan rate higher. The optics just hum drawing those lines (laser video isn't vector scanned like most entertainment laser applications). The beam from a laser big enough to do outdoor video might be 1/16th of an inch or bigger before it even leaves the projector head. So even a mirror just 1/8th wide is needed to scan the beam. And that mirror has to move stop and redraw thousands of times a second. One mirror rotating for horizontal refresh, one galvonmeter for vertical drawing (this is the part that gets really sticky on a big screen) and an AOM for the color changes (a custom grown crystal that will vibrate at different frequencies when in the presence of an RF signal, thus blanking the beam (turning it off and on) and diffracting it (picking the color).
Also, if we could get the color right. Solid state lasers are helping here quite a bit, though the blue lines could still use more brightness. But until the big solid state lasers come down in price, a lot of the pros (and I don't mean the guy who did the lasers at your rave) are still dependent on their ancient SpectraPhyscics 171. Three phase power, a fire hydrant's worth of water, a drain, two men to carry the exciter, two to carry the head, two to carry the projector, and thats just one laser. Our small shows had three (one for full color graphics, two for beams in the air). Mosat guys are now using sold state yags for their beam effects. The solid state full colors are pricey. I believe the laser show at Hershey Park is using a full color solid state laser, I don't know who else, its been a few years.
That being said, laser video is starting to show up in more and more places, and it is looking really good. Just don't expect to be putting one in your living room any time soon. Aside from the cost, lasers are heavily regulated in the US. One bright enough to replace your tv is going to require a whole host of permits from the CDRH (Center for Devices and Radiological Health) and your state, plus don't even think about doing your own laser display outside, the FAA's paperwork will make your head spin.
PS, apologies to all the laser jocks if I got something horribly wrong, its been a few years for me, its late, I have a screaming infant and I'm doing this all off the top of my head.