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Displays

Sony Projector Gets Bright Images From Black Screen 357

da_foz writes "Sony has developed a new projector that can give a bright, unfaded picture without the need to eliminate ambient light. The secret is that they project onto a black screen instead of a white one. Their screen uses species filters so that white ambient light is absorbed, but the red, green, and blue light from the projector is reflected. Sony sees a possible use in home entertainment systems because of the ability to have a much bigger picture than conventional TVs as well as businesses adopting the projectors for presentations."
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Sony Projector Gets Bright Images From Black Screen

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  • Black? (Score:2, Interesting)

    by julesh ( 229690 )
    If it reflects _anything_, it isn't black.

    It seems this is a surface that reflects only very selective frequencies, those used by their emitters. An interesting idea, but calling it black is deceptive.
    • Re:Black? (Score:5, Insightful)

      by confused one ( 671304 ) on Wednesday June 23, 2004 @07:50AM (#9505805)
      It probably appears black (or close to it) from the viewing angle when the projector is powered off.

      • Not being a physicist but having just enough knowledge to be dangerous, I've always wondered how the color black can be projected onto a white screen. I always thought that black is the absense of light. What am I missing here? Is the 'black' being projected just the color of the screen in the dark room?
        • Re:Black? (Score:3, Informative)

          like anonymous said... Basically your eyes, optic nerve and brain as a system is limited in contrast range. To produce a "black" they simply make the other colors so intense, you see "black" where there's a white screen and an absence of illumination by the projector. If the projector is bright enough, you would see "black" in the image, on the screen, even in full daylight.

          We're talking about the some of the same mechanisms that cause you to be temporarily blinded when you walk from a light room to a

    • Re:Black? (Score:3, Interesting)

      It seems this is a surface that reflects only very selective frequencies, those used by their emitters. An interesting idea, but calling it black is deceptive.

      If it looks black to the naked eye, isn't it then... black?

      I wonder if it works with any projector, or just some specific kind. I always liked the picture quality of LCD projectors, but the fact that they require a very dark room to get any kind of reasonable contrast has kept me from buying one. Now this might change that.
      • If it looks black to the naked eye, isn't it then... black?

        Behold the power of the prism....by simply intercepting a path of aparently white light, I present to you all the colours that light is composed of.

        Just because it looks black doesn't mean it is black.

      • Re:Black? (Score:3, Informative)

        by mbbac ( 568880 )
        The article says that it works with normal projectors.
      • Re:Black? (Score:3, Informative)

        It continues a trend that began two years ago when Stewart Filmscreen Corp., a leading U.S. maker of screens, began selling a light-gray screen that enhanced the images from projectors using digital chips.

        I'm just guessing, but since they said "digital chips" rather than LCDs, maybe it has to do more with DLP Projectors [about.com] rather than LCD Projectors [about.com]. Although LCD projectors can be brighter than DLP projectors, the pixels aren't as obvious on DLPs. Perhaps since brightness is a problem, this screen may be b

    • Re:Black? (Score:5, Funny)

      by Anonymous Coward on Wednesday June 23, 2004 @07:55AM (#9505867)
      Pot, Kettle... meet Mr. Projector Screen.
    • Re:Black? (Score:5, Insightful)

      by bs_testability ( 784693 ) on Wednesday June 23, 2004 @08:01AM (#9505933)

      Actually, if it only reflect three specific wavelengths
      then it's probably the _blackest_ thing you've ever seen.
      • Re:Black? (Score:5, Interesting)

        by baxissimo ( 135512 ) on Wednesday June 23, 2004 @11:03AM (#9508071)
        The red green and blue of projectors or monitors or whatever are not a single frequency of light [bu.edu]. LEDs don't give you pure frequencies [ucf.edu] either. Lasers are the only thing that give you light at a pure, single frequency I think. On the other hand, this page seems to indicate that DLP light consists of sharper spectral peaks than either LCD or CRT [avstandards.com] (3rd paragraph).

        But still I suspect that their filters probably filter out some of the visible light coming out of the projectors, making this black screen not quite as bright as a comparable white reflective screen. After all it has to be easier to make a material with close to 100% diffuse reflectance [analytikoptics.co.uk] across the whole spectrum than to create something that's near 0% everywhere except for three narrow notches which are near 100%. But I'm no expert on light

        So I'm thinking it's highly unlikely that the the filters come anywhere near 100% black in the non-reflected parts of the spectrum. No doubt this is the blackest projection screen you've ever seen, but I really doubt it will be the blackest thing you've ever seen. Especially if you've seen Undercover Brother [undercover-brother.com]

        Still it's a pretty neat trick. Anyone know how they make passive filters with such sharp tuning to specific frequencies. Is it some kind of diffraction thing?
    • by FreeUser ( 11483 ) on Wednesday June 23, 2004 @08:22AM (#9506130)
      If it reflects _anything_, it isn't black.

      Of course it is. Every black object in the world reflects some light.

      You are confusing black bodies, an abstract notion defined by physiscists which does not exist in the real, physical world, and the color black, which our eyes percieve just fine whether or not it is a shiny surface with a lot of reflection, or a matted surface with minimal (but still greater than zero) reflection. The black BMW I had the misfortune of following the other day positively glinted in the midday sun.

      With light, black is defined as the abscence of color. With pigment, black is the presenece of all color (analogous to white light).
      • by Mattintosh ( 758112 ) on Wednesday June 23, 2004 @09:22AM (#9506846)
        Pigments are based on light. Cyan, magenta, and yellow are the three primary pigment colors only because they represent the abscence of one of the primary light colors.

        Cyan is the abscence of red. It absorbs red light.
        Magenta is the abscence of green. It absorbs green light.
        Yellow is the abscence of blue. It absorbs blue light.

        And the fourth color found in this group is black, a mixture of all 3 pigment colors. Black pigment is not the presence of all color. It's the presence of all light absorbtion.

        The way that black BMW glinted in the sun is a result of the finish. A nice clearcoat tends to intercept and reflect some full-spectrum sunlight before it gets absorbed by the black paint. A matte finish just diffuses more, yet still reflects that light (just not all in the same direction).

        So... black stuff doesn't reflect any light. At all. It's just the nearby non-black stuff that reflects light, making the entire object appear just almost black.
        • So... black stuff doesn't reflect any light. At all. It's just the nearby non-black stuff that reflects light, making the entire object appear just almost black.

          Okay, so what you're saying is that you have never used the word black to describe a color before, hmm? Because the grandparent's point was that there are no substances that absorb all light in the real world. Yes, hypothetically black is the absence of light, and yes, his example with the car was inaccurate, but we call things black that reflect
    • Re:Black? (Score:2, Informative)

      by AlecC ( 512609 )
      They don't go into the physics. If, as you say, it only reflects certain frequencise, it can approach black - it just depends upon what you define as the cutoff albedo for black: 10%? 2%? 0.1%?

      On the other hand, it might be an angle thing. It absorbs light coming from all angles except a special one, and reflects spherically light coming from that angle. In which case, from all other angles it is black. You could do that by having a set of angled tubes with black exteriors pointing at the projector.
    • hm. you should check this [netcom.com] out
  • by Anonymous Coward on Wednesday June 23, 2004 @07:48AM (#9505777)
    I can see the use in business and public presentations. But other than the few home cinema zealots with giant rooms set up like theaters, how is this useful in the home? To me it seems like having a 24 inch penis. Sure, it'd be big and impressive, but not of much practical use to anyone.
    • Re:100.. 160 inches? (Score:3, Informative)

      by dcocos ( 128532 )
      I have a 92 inch screen in a 13'x12' room at first people thought it would look riduclious but when you put the screen up the room looks a lot bigger and cleaner espcially since there isn't a big (32 inch) TV taking up space like there used to be. Plus I can move the projector and screen by myself the 32 incher is worlds heavier.
    • With a 24" penis, I would be making movies, not watching them.
    • by vslashg ( 209560 ) * on Wednesday June 23, 2004 @08:09AM (#9506000)
      To me it seems like having a 24 inch penis. Sure, it'd be big and impressive, but not of much practical use to anyone.
      God, no kidding. Most people in locker rooms look at me with pure envy. It's nice to hear someone actually sympathize for once.
    • It's useful in the same way a CRT is useful...you can watch TV on it. I've been saving up for a while in the hope of buying a projector and screen, and this is just the icing on the cake. The advantage of a screen and projector is:

      Huge picture

      You can roll the screen up when it's not in use

      This is pretty much perfect for someone like me who lives in a small London flat, but would like to see a decent sized image when watching their DVD collection.

    • Ever read Fahrenheit 451? How do you think they get those wall-televisions to work?
    • That's a woman for you. Looks over practical uses any day.
  • Now if only... (Score:4, Interesting)

    by Insomnia ( 11375 ) on Wednesday June 23, 2004 @07:48AM (#9505782) Homepage
    ...they could come up with a lamp that would actually last. I've gone through at least 6 InFocus projectors in the last 1.5 years due mainly to bulb failure.

    This technique sounds really cool though, perhaps I won't need to have all my windows boarded up anymore. ...hey, what's that bright thing in the sky outside?
    • by ControlFreal ( 661231 ) <niek@berg[ ]r.net ['boe' in gap]> on Wednesday June 23, 2004 @07:57AM (#9505892) Journal

      When your screen doesn't reflect so much of the ambient light anymore, you can use a projector that outputs less power. For one, this can lead to less hot projector lamps, thus a longer life for them.

      It might also enable the use of lower-power technologies (LED-lasers anyone?), that might in turn make the projectors much cheaper.

      Nice work by Sony



      Now, is there a physicist in da house who knows how wide the reflection-band (in wavelength-terms) for R, G and B is?

      • Unfortunately, this is only true if you are running your bulbs extra-bright so you can watch in an undimmed room. In a dark room the screen is no brighter than a white screen, and so requires the same brightness of bulb.
    • Re:Now if only... (Score:3, Interesting)

      by artemis67 ( 93453 )
      How does one go through 6 projectors in 1.5 years? I bought a Toshiba projector 5 years ago, and have yet to replace the bulb. You must be running this thing 24/7. Also, when you turn off the bulb, do you let the fan run until it stops on its own before you unplug the projector? Not letting the fan run after you turn off the bulb will also shorten the bulb's life.
    • Re:Now if only... (Score:5, Informative)

      by Lumpy ( 12016 ) on Wednesday June 23, 2004 @08:38AM (#9506300) Homepage
      I've gone through at least 6 InFocus projectors in the last 1.5 years due mainly to bulb failure.

      while I have the same bulb from 2 years ago still burning bright.

      it's your use of your bulb and projector.

      first off, buy a UPS for your projector and put it on there... only the projector goes on this ups. you want to be sure that your voltages are rock solid and no brownouts get to the bulb. Finally you are making sure that the projector is cool and is allowed a proper warm up and cool down before and after use?

      proper care and operation of your projector lengthens bulb life significantly. if you are leaving the house for an hour then LEAVE THE PROJECTOR ON.. I would not shut off the projector unless I was going to have it off for more than 2 hours.
      • Re:Now if only... (Score:3, Interesting)

        by mbourgon ( 186257 )
        I'm looking at getting an X1 or equivalent later in the year. When you say "leave the projector on" do you mean with the bulb burning and everything? I assume so, but want to be sure.

        If so, my wife will love you - I tell her to turn off the TV if she's away from it for more than 30 minutes.
        • Re:Now if only... (Score:4, Interesting)

          by Lumpy ( 12016 ) on Wednesday June 23, 2004 @10:52AM (#9507882) Homepage
          yes bulb on and going strong....

          turning that bulb on and off does more to it's life than leaving it on... now leaving it on 24/7 will get you to the diminished light output and dead point far faster, but you can easily triple your bulb's typical life by leaving it on when you are not going to be watching it for short peroids of time.

          also don't even be tempted to enclose the projector. it must have free air flow from all sides and NOT be located near a AC/heat vent.
      • I would not shut off the projector unless I was going to have it off for more than 2 hours.

        Now that's what I call stamina! [reference.com]

    • Re:Now if only... (Score:3, Informative)

      ...they could come up with a lamp that would actually last. I've gone through at least 6 InFocus projectors in the last 1.5 years due mainly to bulb failure.

      I had a similar problem with my projector (an older SharpVision) destroying my bulbs. Not just burning them out, but warping them. Fortunately, I had the extended warranty and they eventually replaced the main board (which apparently includes the power supply and LCD arrays, since the power plug was new, and the dead pixels had moved.) No probl

  • Woah, neat! (Score:3, Funny)

    by dkf ( 304284 ) <donal.k.fellows@manchester.ac.uk> on Wednesday June 23, 2004 @07:49AM (#9505788) Homepage
    Absorbing everything except the wavelengths that the projector produces (and which the human visual system will still perceive as the full spectrum of colours) is *very* clever. If only the ambient light wasn't from massed banks of computer monitors...
  • Finally (Score:5, Funny)

    by Todd Fisher ( 680265 ) on Wednesday June 23, 2004 @07:49AM (#9505798) Homepage
    We'll finally be able to see the Gettysburg Address Power Point presentation the way Lincoln intended it to be viewed.
    • Re:Finally (Score:2, Funny)

      by Amata ( 554796 )
      That's almost not funny. The amount of PowerPoint involved in a briefing involving several Generals during an exercise is astounding.

      However, now those powerpoints can be shown on a nice "panel" instead of having to buy a bunch of big monitor type things to form a video wall that was used to replace old projectors.
  • by ironring ( 598705 ) on Wednesday June 23, 2004 @07:52AM (#9505824)
    This appears to be a very cool technology. I have wanted to put a front projection system into my home, but have no way to control ambient light during the day. When this screen becomes available, it will probably push me over the edge.

    I assume the three frequencies that are reflected are fairly well tuned. I wonder if this means I will be stuck purchasing a Sony projector to match these? I also wonder if Sony may be able to stop others from making matching projectors since they probably own some Patents around this technology?

    • Don't worry. If it catches on at all, other companies will gladly pay licensing fee for the patent and then have to eat the cost as more and more people make projectors that use the 'black' screen. That's the way patents are supposed to work--that way those that do the work get paid and others can benefit from the work for a price.

      Patents aren't the same in computer land. In computerland a patent is a weapon with which to kill your competition with fees prevent them from building on the tools you c
    • I also wonder if Sony may be able to stop others from making matching projectors since they probably own some Patents around this technology?

      Sony is no Redmond company. they will most likely license the technology to competitors, or Sony's competitors will come up with something similar or better. I don't know if Sony has any type of deal with this "Stewart Filmscreen" company, but Sony knows how risky it is to play "exclusive" in the market and make things incomatible from rest of the world. Sony wil

  • but... (Score:2, Redundant)

    by matticus ( 93537 )
    what if the projector is projecting ambient-looking light?

    /head asplode

    • The pseudo-white you get by mixing pure red, green, and blue does not suddenly become a "real" spread-spectrum white. It only looks that way to us because the color receptors in our eyes pick up those three wavelengths, so we can't tell the color is any different.

      (Note that this is not the *whole* story, but it's close enough for a general explanation of why a filtered screen is a cool idea.)
  • by G4from128k ( 686170 ) on Wednesday June 23, 2004 @07:52AM (#9505830)
    It would seem that the ultimate version of this would use RGB lasers as the light source and notch filters on the screen. The narrowness of the notches would determine the depths of the black. The biggest trick would be in tuning the notch filters to reflect the off-axis, angled laser light.
    • The thesis that monochomatic sources and tighter filters would help sounds good. True notch filters would probably have too much angle dpendence but very narrow filters could be made.

      But I still dont understand how the screen works with current projectors. Current projectors use a broad band light bulb and separate the spectrum into three componenets. They cant be highly narrowing the bandwidth of the of these components or they would be throwing away most of the light.

      ergo, current projectors must be

    • I came across this [zeiss.de] on the internet when I was looking for something on RGB lasers a while back, and this [photonicsonline.com] just now. Ever since I heard that blue lasers had been invented years ago, I've been waiting for them to be used for projection displays, because there already were green and red ones.

      I think they could be better than projectors that used lamps because they could probably last longer. They shouldn't need to be focused either, because a laser can act like a scan line on a surface directly (like an elec

  • I just bought a Sony VLP-HS20 and now they come out with this, I could have painted the walls white and hung a black screen :-( Instead of painting them dark and hanging a white screen.
  • by dylan_- ( 1661 ) on Wednesday June 23, 2004 @07:52AM (#9505838) Homepage
    This isn't a new projector. It's a new type of screen that only reflects the projector light, absorbing the ambient light, so the image remains clear even in a bright room. It works with regular projectors. I'd at least expect the submitter to RTFA...
  • Who wrote this? (Score:4, Informative)

    by julesh ( 229690 ) on Wednesday June 23, 2004 @07:55AM (#9505870)
    The author of the article doesn't know what he's talking about!

    In a bright room, the image on the screen is brighter

    No, it isn't. It's clearer, it might _appear_ brighter because of that, but there's no way it could actually _be_ brighter. Unless the technology does something not described.

    Since Thomas Edison introduced motion-picture projectors more than 100 years ago

    I could have sworn the motion picture projector was introduced by Lumiere.
    • by valderost ( 668593 ) on Wednesday June 23, 2004 @08:36AM (#9506277) Journal
      Be careful applying non-technical terms in technical discussions.

      The common vernacular "bright" can either refer to luminance (close the shades, the light's too bright), or it can refer to color saturation (Can you tone down that bright green to a mere pastel?). A projector screen that reflects ambient light is going to reduce color saturation; and one that absorbs ambient light will increase color saturation, i.e. make it brighter.

      • I'll admit I was confused by that. The usage of "bright" to mean highly saturated is a familiar one, of course, but I only tend to think of it in terms of reflective colouration. As in: the colour is bright green because a large proportion of the green spectrum is retained when it reflects white light, so if you viewed it through a green filter it would be relatively bright.

        But thinking about it, it _does_ colloquially simply mean saturated.

        Yeah, OK. The author was just being ambiguous, which is what y
      • Hang on, in this case we aren't talking about luminance OR saturation. We are talking about contrast. The "black" screen gives us contrast. A darker "background" to compare our signal against.

        Six o' one, half dozen of the other, but a little one watt bulb can illuminate a room in the absence of any other light. (I regularly use the back light of the phone to track down lost pacifiers under my daughter's crib in the middle of the night.)

    • Lumiere didn't take credit for his projector, instead saying it was an enhanced version of Edison's kinetoscope.
    • Don't you know EVERYTHING was invented in Amerika?
      Mostly by <American Hero> Tomas Alba Edison </American Hero>.
  • by hamburger lady ( 218108 ) on Wednesday June 23, 2004 @07:59AM (#9505909)
    Sony created a new projector, eh?

    fourth sentence of the article:
    In apparent defiance of color theory -- that dark surfaces absorb light and white surfaces reflect it -- Sony Corp. has unveiled a black screen that allows a regular digital projector to vividly display TV images and business presentations in a brightly lit room

    jesus christ, is it too much to ask to have someone read the fscking thing first??

  • by ianscot ( 591483 ) on Wednesday June 23, 2004 @08:04AM (#9505957)
    Whatever other merits this turns out to have, it's going to pack that "Whoaa" reaction the article described at the trade shows, for sure. People respond to contrast.

    I bought some high-end binoculars a while back. When you're looking through all the Nikons and Swarovskis and Leicas side by side, you start to realize when your eyes feel the little zing. It isn't pure resolution that does it, and your eyes compensate rapidly enough to changes in brightness (due to objective size or quality) that you don't often perceive differences except at dusk and dawn. (The only exceptions for me were old-style tank commander Zeiss binocs. Very bright.)

    But when you hit a binoc that felt right for contrast, ahhh -- those were my handful of last choices. It's like seeing the world with the slanting light at around 6:30 on a summer night -- everything just pops out, so clear, and the slight 3-D exaggeration of the binocular view brings it out just that little bit more. The optics store people said that was a pretty common reaction -- a slight edge in contrast was a huge advantage.

    Sounds like this screen has that going for it. Big selling point, next to potential competitors, if they can get it around the right price point.


  • Sony engineers worked from the basic principle that projectors, like all TVs and monitors, form colors by blending three primary hues: red, green and blue. They came up with a filter that allows the screen to reflect only red, green and blue light. The other light in a room, such as white incandescent or fluorescent bulbs, isn't reflected.

    ...completely skirting around the fact that THERE IS NO SUCH THING AS WHITE LIGHT!

    Man I hate it when the newspapers print stupid things. Whaddaya wanna bet they are using something like polaroid or narrow bandpass quarter wave plate filters with a similarly filtered projector? What would be cool is a fluorescent screen and a projector that uses light (UV?) outside the visible spectrum. Then the screen really could be visibly black but it would still glow when stimulated by the projector.
    • completely skirting around the fact that THERE IS NO SUCH THING AS WHITE LIGHT!

      Sure there is, there's no such thing as white monochromatic light, but white light exists. The term "white" (whether it be talking about light, sound, etc.) simply means that the energy is distributed evenly across all frequencies (technically between 0Hz and infinity, but in practice we're talking about more or less evenly over a given band of frequencies). Since the energy is distributed over such a wide frequency band, the energy of the white light in the very fine bands used by projectors will be very small, so by absorbing everything else you will almost be eliminating the white light's energy.

      Trueth be told, unless you're talking about monochromatic light, the simplistic names of colours only describe what we see - they can be generated by any number of combinations of different frequencies. I.e. monochromatic orange light has a wavelength of 590nm, but that would look the same to us as a mixture of red (650nm) and yellow (570nm) light (or any number of combinations of different wavelengths).
  • DLP or similar (Score:3, Insightful)

    by RealErmine ( 621439 ) <commerceNO@SPAMwordhole.net> on Wednesday June 23, 2004 @08:08AM (#9505991)
    The article specifies that this is for use with digital projectors. I assume the reason for this is that single chip DLP projectors don't actually project white light onto the screen. The red, green and blue components of the image cycle so fast on the screen that your eye perceives this as different shades and combinations including white. All you need to do is have the screen absorb white light while reflecting red, green and blue and there you go. This is really an ingenious use of this effect, but I wonder if it is unusable with a 3 chip DLP projector that shows all components at the same time? You would at least need a more sophisticated screen in this situation.
    • Actually, from what I've seen most do have a white slot in the color wheel. Helps improve the brightness. Remember reading something a few months back (memory is a bit fuzzy) how people were taking apart a certain projector (x1?) and darkening the white slot to get lower black levels...?
    • Re:DLP or similar (Score:3, Interesting)

      by Aidtopia ( 667351 )

      Some of the cheaper DLP projectors use a clear segment in their color wheels in addition to red, green, and blue. This is done to get an overall brighter image at the expense of saturation. I suspect these projectors wouldn't look so good with a screen like this.

      I suspect the screen will be expensive, so people spending that kind of money on the screen will have a "pure" RGB projector.

      Does anybody know if LCDs and DLPs use exactly the same RGB primaries?

  • by ironring ( 598705 ) on Wednesday June 23, 2004 @08:08AM (#9505992)
    This reminds me of a technology I read about [ucf.edu] a while ago. You can dope crystals with rare earth elements in such a way that when they are illuminated with infrared light, they up-convert (heterodyne) it to some part of the visible spectrum. The doping of the crystals can be controlled to produce red, green or blue light.

    These crystals can be ground up and painted onto a screen or even the side of a building. Then all you need is an infrared laser to scan the the sreen and you have an extremely bright and cheap full color display.

    I haven't heard much lately about their progress so I assume they are having some technical or financial delays.

  • If you combine RBG light you get a white ish looking light. So how does this work? Is it reflecting only the light frequencies the RBG projector is showing.

    Each type of light bulb gives off multiple frequencies some of which must overlap. Unless they're also using the incoming angle to control reflectivity.

    There seems to be more to this than the article is describing.
  • Fan Noise (Score:2, Interesting)

    by thpdg ( 519053 )
    Even with the best surround sound, there is still the issue of fan noise. If you enclose your projector in a cabinet, you shorten the bulb life due to heat. I've used various projectors over the years, and always end up back at my HD flat-tube system, because it has good contrast and is quiet. If they fix the contrast problem, I may give projectors another look, but the fan noise should become top priority.
    • I have a rather old projector (LP420 infocus) that won't even accept a ceiling mount, much less not have an option to flip the screen if one were available.

      Since it is a DLP projector, it's got a color wheel that spins. I could probebly accept the fan "whoosh", but that color wheel motor seems to put out a majority of the noise/whine.
    • Perhaps my ears are not as sensitive as yours, but I have practically no fan noise from my LCD Sanyo Z2 projector, and I'm usually sitting right below the thing so if noise was an issue I'd be the first to be screaming about it.
  • Never mind about the projectors. I want to be able to use my laptop outdoors. There must be a reason I have wireless lan and a balcony. Since the root of all problems is that screens have luminosity instead of reflecting existing light selective reflection seems very interesting.
  • An LCD project emits red, green, and blue light at specific frequencies. The screen is tuned to reflect these and only these frequencies as much as possible. Ambient "white" light includes the whole visible spectrum, the vast majority of which isn't reflected by the screen. Only those frequencies close enough to the LCD frequencies would be reflected.
  • They are using this technology to make objects "Invisible", here's how.

    They have a subject standing in front of an object, say a wall or even street traffic. Behind the person is a camera that records the scene behind the person.

    The person is dressed up in the special black fabric that reflects the RGB light.

    A projector in front of the person projects the image from the camera stationed behind the person, onto the person... this makes the person the movie screen and enables you to "see through" that per
  • Well just will be a boon for the drive-in movie crowd in Alaska during the Midnight sun
  • by dpbsmith ( 263124 ) on Wednesday June 23, 2004 @09:13AM (#9506714) Homepage
    As others have pointed out, a truly black screen wouldn't reflect the projector's light. And, conversely, a screen that is able to reflect the red, green, and blue light from the projector will reflect some of the ambient light, which contains some light at the projector's R, G, and B wavelengths. It's too bad the article has to describe it as "Gee whiz! it's technological magic!"...

    What we need to know is: a) what percentage of white, ambient room light does the screen reflect? It's not zero, and the screen probably looks like a dark grey. b) When the projector is projecting "white" light, what fraction of that light is reflected? Not only is it less than 100%, it's probably less than a white screen would reflect.

    Other things one would like to know are whether the filters that do this magic cause any visible graininess, and over what angle the reflected light is reflected.
  • by mcg1969 ( 237263 ) on Wednesday June 23, 2004 @09:14AM (#9506723)
    The technology here is in the screen, not the projector. In particular, the screen absorbs most light, with the exception of the primary bands illuminated by the projector's bulb.

    Any projector with the same type of bulb---and in home theater nowadays, there are only two main types (Xenon and UHP), will work with this setup. And Sony could conceivably make a similar screen for the other bulb type too.

    There have been so many dupe threads over at AVS Forum [avsforum.com] (by far the best place to go to discuss anything home theater) that it is getting a bit irritating.
  • TRATEOTU (Score:3, Funny)

    by goldmeer ( 65554 ) on Wednesday June 23, 2004 @09:22AM (#9506838)
    Ob Reference:
    I always wondered how Hotblack Desiato's ship was detailed so, well, black. Now we know. It's still a shame about the tax thing.

    NOTE: If you don't understand this post, don't moderate it! Yes, I mean you. I'm not being funny here! Stop it!
  • by Militant Apathy ( 99335 ) on Wednesday June 23, 2004 @09:30AM (#9506934)
    A related technology that could make notebook computers usable outdoors would be the real killer app, as far as I'm concerned.


    It seems like a feasible variation, at least to me -- keep the mostly-black coating to absorb nuisance ambient light, but allow transmission at narrow RGB wavelengths. Then backlight it with an LED screen, with the diodes tuned to the three transmission frequency ranges.


    Don't know whether it's technically possible, but if it is, I bet it's in the works already.

  • by lub ( 188080 ) on Wednesday June 23, 2004 @10:06AM (#9507283)
    This patent [uspto.gov] from Sony gives some detail. To view the images, you need a tiff-viewer plugin [uspto.gov].
  • by jpellino ( 202698 ) on Wednesday June 23, 2004 @10:11AM (#9507342)
    "It's like, how much more black could this be? and the answer is none. None more black."

Understanding is always the understanding of a smaller problem in relation to a bigger problem. -- P.D. Ouspensky

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