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We've been through B/W TV, then colour and now digital or even lcd TV But why has nobody thought of using a blue, green and red laser in place of the conventional cathode ray gun and a few fancy optics and a laser etched flat screen of virtually any size, the laser TV could probably encode normal broadcast
signals incl. digital and hey presto you have a real 3 dimensional holographic picture and because there is virtually no divergence of a laser beam it should be possible to project an image to virually any size. Throw away those silly 3D glasses and watch real TV.
Hologram projection TV
http://www8.techmal...ocs/NP991217-2.html
Baked, without lasers. [angel, May 25 2001]
How it could be done
http://www.spie.org.../may/may97/slm.html
Do a <ctrl>-F for 'holographic tv' [angel, May 25 2001]
Wikipedia article
http://en.wikipedia...Laser_video_display
The idea has been around for a while, and is perhaps now practical --well, maybe not yet the 3D version. [Vernon, Dec 11 2012]
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You're right, [Rods]; on reflection (no pun), and after reading the JVC blurb in more detail, it's not real 3D. But it's still at least half-baked (see second link). |
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I was thinking of something like this years ago. The big problem is having the beams scan across the screen at high speeds. I fighured an electric current could go thru a quartz so it will vibrate at the right speed. place a mirror or lens on the crystal and it will aim the beam at the right speed.
The different colors are done the same way as on a CRT set, 3 different beams with a different filter. |
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--Kodak in Rochester NY has a all LASER digital projector prototype. |
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Wouldn't you have a problem with colour gamut? Lasers are intrinsically narrow spectrum devices, so I'd imagine you'd have problems where the spectra of the component lasers didn't overlap. |
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//Lasers are intrinsically narrow spectrum
devices// yes, but shirley so are the
phosphors in a CRT? Why do you want
spectral overlap? |
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[MB] Interesting point, and one I confess I don't fully understand - I guess it is down to the eye's relatively poor colour perception.
The gap in the spectrum between green emitters and red emitters is usually quite large, and I seem to remember in the late 1970s that Panasonic introduced the Quintrix CRT with red, green, blue and yellow phosphors(I can only assume they got their "quads" and "quins" mixed up) to improve colour reproduction.
However, googling, I can't find anything to support this possibly false memory. [goes off to research colour reproduction] |
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recently <mumble>'s come out with 4-colour led screens. |
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They seem to be LED lit LCD screens (not LED screens), and they would need to shift to a shorter wavelength blue to cover that end of the visual spectrum properly. Still, industry is finally admitting (again) that RGB is flawed! |
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