

Using an LCD’s poor viewing angle to your advantage - dholowiski
http://chrisharrison.net/index.php/Research/ObliqueLCD

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tsotha
I used to work at a place where our work product was kept in safes. They had
these funky electronic locks, and instead of having notches on the dial there
was a little LCD window on the top (facing the ceiling). Whereas most LCD
manufactures try to get a wider viewing angle, the manufacturer had gone the
other way, so you had to hold your head in exactly the right place or you
couldn't see the numbers as you dialed the combination.

There was no way you could shoulder surf the combination. Even if you planted
a camera the head of the person opening the safe would be in the way of the
camera's sight line.

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miahi
You can do that with any display. They are called privacy filters, you just
stick them in front of the display and work exactly as you say.

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kmfrk
More technically polarization filters. Laptop/Desktop manufacturers usually
sell these at an obscene price, but there has to be a place to get them for a
more reasonable price.

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archangel_one
I wonder if this may have come a bit late to be useful - I can't see that
colour inversion effect on my laptop monitor even at fairly extreme angles, so
I'm not really confident that it's going to work on here. The advance in LCD
technology may prevent this seeing any serious adoption, although I do think
the "unread emails" one is pretty nifty. I'm not so sure about the banking one
since I'm very unlikely to do any banking with someone sitting nearby, even if
I knew a technology like that was in place.

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wanorris
There are still plenty of cheap LCDs in the world, they just don't show up in
high quality products. I bought a cheap Android tablet (a Viewsonic gTablet) a
while back to try out, and it had terrible viewing angles.

The banking example on the site actually implies designing an ATM specifically
to take advantage of this feature. There are often people around you when you
use an ATM.

Other products where security is an issue (special more-secure laptops?) could
be designed this way as well. You wouldn't do banking with people watching,
but if you needed the ability to do company work while, for example, spending
a lot of time flying, it might be a net benefit.

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doctoboggan
This is a great example of the old engineering adage that you can turn every
fault into a feature.

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jberryman
I thought that was an old jazz musician's adage ;-)

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bullsbarry
If you make a mistake, repeat it and call it your own arrangement.

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amuhtar
The thing I find amazing is not so much that they were able to use colour
refracting to overlay invisible messages on bad LCDs... it's looking at the
problem in "creative-reversedness" (yes I just made that up).

We all would look at the limited viewing angle as a problem. Not enough people
can see the TV, colour is bad, blah blah. But if we were to look at the
problem in reverse - Too many people can see the screen from all angles,
colour acuracy is not that important for all applications, and so on... we
actually define a product that we can fit in the banking, HR, etc roles.

The next feat of genius was looking at what was causing the original problem
and then leveraging it to create the new fuctional solution. Many just use the
polar lenses, now you can just create a app that overlays invisible ink.

Great job.

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Flimm
Could this be used to correct my posture? I can just imagine my screen telling
me to "sit up straight!" every time I slumped just like my father used to.

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jaylevitt
No, for that you just need PostureMinder:

<http://pcbackpain.com/how-postureminder-works/>

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anjc
This seems pretty cool. But is the viewing angle of an LCD an inherent
property of the particular materials used or is it a side effect of uncertain
manufacturing processes? I.e. could an LCD screen's viewing angle be changed
if it was manufactured more precisely or calibrated better or something?

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LokiSnake
It's definitely dependent on the LCD monitor. I have a TN monitor, which works
with the demo page, but on my IPS monitor, the text never really disappears
from any angle.

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anjc
Sorry what i meant was, even with the same brand and manufacturer, might there
still be slight differences in viewing angle depending on how well each
individual monitor was made/calibrated? My point being that, as cool as the
idea is, mightn't it be impractical if you have to test/calibrate every
monitor that's used, versus a manufacturing process that takes the usage into
account from the beginning.

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cccccc
The works on even mac laptops

go to the demo page here: <http://chrisharrison.net/projects/obliqueLCD/>

look at your laptop screen from above and below (i.e., tilt or rock it) - not
side to side.

More details here: <http://chrisharrison.net/index.php/Research/ObliqueLCD>

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thristian
I could easily read all the text on that demo page, even when looking at my
monitor head-on.

Turns out, the 'secret' text is coloured to blend in with a white background,
but the page doesn't actually _enforce_ a white background; my light-grey
background doesn't provide enough contrast to read a novel, but it brings out
the 'secret' text nicely.

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CosmicShadow
This is definitely cool, but I still hate shitty LCDs. I bought 2 separate
Samsungs that said they could pivot, but both (being made years apart) still
had such horrid viewing angles that even looking straight on while vertical
would make that distortion effect and make me feel sick.

I fought Samsung for false advertising using every method I could find and
eventually they just gave me 2 24" IPS's and a 22" that can do 3D. The IPSs
are really nice, but you can fry an egg on them they run so hot.

Using one of those shitty monitors if I get to the sweet spot where the text
is invisible, if I move a hair up or down I can see the text :S

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dotBen
In one example they have blurred the financial details on the screen from
anyone viewing from the side.

I wonder if that could be iterated further such that all of the screen is
blurred from the sides (presumably by dynamically altering the "overlay" to
cancel out each color of each pixel).

This would then make a great alternative to a privacy screen for use on
planes, etc.

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CosmicShadow
Don't ATMs do something like this, or are they just built to have the
shittiest viewing angles ever (which is obviously advantageous for this
scenario)?

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kronusaturn
They have privacy filters, a separate covering that reduces the viewing angle
of any screen to almost zero. You can buy one yourself, if you want.

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rottendoubt
I wonder if this could be used for a game somehow...

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joejohnson
That banking example would be better if the text viewed from an angle obscured
the bank balances as well.

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sliverstorm
One of the later examples does that.

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pguzmang
Currently, you can buy a private filter for any monitor and you can see what
is in the monitor only if you are in front of it. I think they should develop
their own devices with the applications to sale them.

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hippiecow
Wow - I saw one of the monitors I currently use in their "Photos" section.

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smork
Isn't this old news? [http://www.engadget.com/2009/04/08/2010-range-rover-
gets-12-...](http://www.engadget.com/2009/04/08/2010-range-rover-gets-12-inch-
dual-view-touchscreen/)

