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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."
The largest silicon chips approach a billion devices at a cost of $0.0001 cent per device. What is the manufacturing efficiency of carbon fibre?
No, its not such a new and great idea. Schneider was building a project "laser tv" 15 years ago.
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No, they are missing one thing: Brighness still does need power. While lasers have become more efficient, and the lifetime of blue ones doesnt suck anymore (thanks to lots of $$ invested by storage companies), there is still physics to play with:
with a perfect display screen, you need at least 15W (rough estimate, dont care to converte the lumens right now) of photon power per m^2 to get a usable picture.
That of course would mean you would need those 15W in Laser emitters. As tubes are prohibitively expensive, that means diods. Diods are a _bit_ heat sensitive (they die like flies if anything is not to their liking), and i havent seen 5W or higher diods without a good cooling solution (because they will still protuce 2 times as much heat as light, and that in a very small volume.
Not to mention the little fact that a single 1W blue laser diode right now would be more expensive than a HD-Dlp beamer (plus it would degrade quickly to unusability).
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
Since it uses one fibre per scane line the oscillation rate is the same as the refresh rate.
Have you ever taken a picture of a CRT with a camera? Unless you drop the shutter speed real low you only get an inch of the displayed picture. The parts directly before the inch of graphics are not faded, but rather completely black. The visual dropoff for the pixel is extremely quick, and the dropoff for your retinas is by far slower. A laser based device would have to be about 75hz not to cause noticable flickering, just a CRT.
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Well, they're talking about two things, they probably mean that the modulus of elsticity (the "stiffness", based on Young's Modulus, expressed in psi or pascals) is double that of silicon, but the yield point, or flexibility (how far it can bend before it permanently deforms) is 10 times that of silicon. It's a dumbing down of the mechanical properties using common language and, no, it really doesn't make sense the way they've presented it if you try and apply logic to the langugae they've used.
Is it just my observation, or are there way too many stupid people in the world?
Green would actually need to be a lot less power, since your eyes are much more sensitive to green than anything else. A 5mW green YAG looks a hell of a lot brighter than a 5mW red diode, for instance. Similarly, you're less sensitive to blue, so the blue component would have to be ramped up to compensate. I've yet to see any low-cost solid-state blue units yet, though.
Please stand clear of the doors, por favor mantenganse alejado de las puertas
The Virtual Boy had a single column of LEDs and a vibrating mirror for each eye.
It looks like they've replaced LEDs with lasers and more of them.
I'm still waiting for cheap small (2" max in width/height) high resolution (640x480 min) LCD displays so we can finally hook up head mounted 3D displays to our next gen game consoles that have dual video out so you can hook one console up to two TVs for dual player action/wide screen action or to one pair of 3D glasses so we can view our 3D games in 3D.
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"Volume of air moved" is the wrong way to think about speakers (because its a meaningless construction in terms of physics). The correct way is in terms of impedance matching, i.e. efficiency of power transfer across the spectrum between the driver and the medium (e.g., open air, an ear (circumaural headphones), an ear canal (insert headphones), water (hydrophone), etc)
A large cone attached to a driver is one way to get good impedance matching for delivery of a low frequency, but not the only one and not necessarily the best since it has some drawbacks (mass, flexibility, fragility, etc). Even so, its often not that good, and a lot of speakers end up being absurdly overpowered because they are so inefficient. Its like having a sports car with bald tires... pointless.
Another way to do impedance matching is with an exponentially tapered waveguide, i.e. a horn. e.g. a brass instrument or an old acoustic record player. I don't vouch for the quality of Bose products, but the Bose "Wave" product essentially contains a long waveguide hidden in the box.
Other tricks include stuff like bass porting and resonant cabinets, and on most speakers you will see some combination of all the above.