Stop people peeping at what you are looking at on the screen with the following simple device. The screen displays random noise, apart from the precise area (maybe 1 sq cm) that you are looking at. This can easily be determined using Body Position Garment and Glance Direction Specs (see links below). The view area displays what is really meant to be on the screen at that position. You will see a completely normal display, but a casual observer will see only noise.
With the arrival of active paper, this idea could be applied to books and newspapers, thus preventing others reading them over your shoulder on the tube.
(The principle of this idea, ie displaying only the viewed area and changing this in response to the viewers eye movement, is not original. It is described by Daniel Dennet in Consciousness Explained (I think), from a psychological perspective. He reports that it really works. I believe my application to be original, however others may know better.)-- Mickey the Fish, Jul 15 2000 Body Position Garment http://www.halfbake...0Position_20Garment [Mickey the Fish, Jul 15 2000, last modified Oct 04 2004] Glance Direction Specs http://www.halfbake...20Direction_20Specs [Mickey the Fish, Jul 15 2000, last modified Oct 04 2004] Virtual Retinal Display http://www.hitl.was...n.edu/research/vrd/The Ultimate 'Your Eyes Only Screen' [dgeiser13, Jul 15 2000, last modified Oct 04 2004] 3M Brightness Enhancement Film http://www.3m.com/i...hive/full_02.html#c"For the observer, the light seems brighter when viewed vertically. When viewed from the side, nothing can be seen." [andrewm, Oct 04 2004] SOLOvision PDA screen protector http://www.ttools.c...curity_screens.htmlOnly he who looks directly into the screen sees. Usually. [galukalock, Oct 04 2004] Baked! http://www.wired.co....10/play.html?pg=10Wired reports on Japanese lenticular privacy screens for cellphone handsets [Chrontius, Oct 29 2004] More on above-mentioned VRD http://www.thefeatu...le?articleid=101184Definitely being baked. [Vernon, Oct 29 2004] Apparently you can get high security laptops with the top polarizer removed, and a pair of polarized glasses. Nobody who isn't wearing shades with the right polarization can see anything on the screen, or just very faint images.-- StarChaser, Jul 15 2000 Wouldn't a little blob of content skittering around on a field of snow be obvious? I know my eye would be drawn to the blob of content; it would be a little tricky to follow along, but I'm sure I would get some information.
Instead of totally random noise, the rest of the screen should contain a constantly changing mishmash of fake screens that contain false data but otherwise look real (window dressings, text content, graphics, whatever you were doing). Then it really would be impossible to sort out what was going on...-- egnor, Jul 15 2000 So you're glasses are by default endarkened. They are endarkened at-a-failsafe.
Then what about every 24th or 50th or whatever-it-is-these-days frame or so being sensible, whilst all the others are random and rubbish, and perhaps out-takes from some bad TV-thing about clever pets or so.
Then, a wee little bit of time before the sensible frame was about to be shown, the telly sends a signal to your glasses telling them to prepare.
So they show you're fine frame.
In the next second the fine frame would be at a different juncture. And so on. To you with you're glasses the picture would be jerky and slow, but no worse than many things. Or one could speed up the frame-rate using crystals and such-like.
In any case, without a glasses of your own you would be safe from EYES.-- eehen, Jul 16 2000 I think I like eehen's version better...-- egnor, Jul 16 2000 If I was close enough to the screen to see it and it was that important, I'd just record the EM radiation from the screen and decode it at my lesiure.
A simpler idea for a 'secure' screen is to just use LCD with a very narrow angle of view. Standard LCD screens have a narrower angle of view than CRT monitors, and it would be not too hard to manufacture an LCD screen with a very narrow angle of view, such that to see anything your head would have to be in exactly the right place.-- hippo, Jul 17 2000 A problem with eehen's scheme is that the screen brightness would have to be increased x50 (or whatever the bad frame / good frame ratio is), to maintain the perceived brightness. This assumes that the frame rate is increased to maintain the illusion of continuity. Also, the user's view of the rest of the world would be dimmed by the same factor. The cueing signals from screen to specs could be encoded in the bad frames, but would need to be encrypted to prevent other spec wearers overlooking.-- Mickey the Fish, Jul 17 2000 Why not do away with the screen altogether and invent a pair of glasses that can be plugged directly into your PC or whatever, and have the contents transmitted directly to the back of the lenses?-- DrBob, Jul 17 2000 Mickey: Not necessarily. If the glasses were shaded, then the whole world would be darkened by a factor of 50 (or whatever). Human eyesight can easily adjust to compensate, as long as the screen was relatively bright to begin with.
(Of course, taking off the glasses will feel like walking out of a movie theater...)
DrBob: Because LCD shutter glasses are easier to design and cheaper to implement than full-on VR goggles.-- egnor, Aug 23 2000 Perhaps a highly lenticular screen that prevents viewing when the viewer is, say, more than 2º off axis. Maybe such a screen could even be switchable between wide and narrow . . . The LCD screens of yore were hardly readable when the viewer was off axis, maybe that bad trait could be reintroduced as a good trait. In fact, there probably exists such a "lens," a privacy shield, already.-- bristolz, Oct 21 2000 It needs an optional on-off perhaps, but an external vga/ usb output might get around that.-- gz, Apr 25 2001 Re: eehen's idea: if you have shutters over your eyes, just have every other frame contain an inverted image (perhaps dithered). An unaided viewer will see the 2 alternating images blend into uniformity, while the shutters alternate on/off to show you only the correct frames. Like what you are saying, not 1/50 but 1/2.
Re: bristolz's idea: I used to work for a company that made bank teller machines. They wanted it so that even someone standing next to you could not see the display. They covered the display with a screen that had many fine parallel ribbons embedded in the plastic, a little like the louvers in a left turn arrow traffic signal. Low tech and works very well at letting almost all the light through at the correct angle, and obscuring all of it off-angle.-- jtgd, Jun 05 2002 I seem to recall a speculation/extrapolation somewhere about a device that would send a beam (laser?) through your iris in order to "paint" the image, line-at-a-time, directly onto the back of your eyeball.-- NomadOfNorad, Aug 02 2003 [bris] There does indeed. Only for PDA's, though.-- galukalock, Aug 03 2003 random, halfbakery