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[interestingly, and Ive never noticed before, but theres no
Public:Transport category, which is the obvious place to post
ideas about the tube and buses and trams and suchlike.]
Preface: I had this idea yesterday when I was out, but a not
unrelated idea was affixed to the half bakery by
in the meantime.
In doing so, I was thinking of asking the half bakery peoples in
general a quick question (which it, we all agree, isnt really
designed for, but theres a lot of things its not designed
either). Hence, Im going to ask my question here, as its not
Half bakers do you know of a way of having a display and a
window be the same thing at different times? In other words,
when the display should be displaying something, its the
same as a conventional transmissive display. When its not
supposed to be displaying something, it stops displaying
anything but then becomes basically a window and lets you
see through it unhindered and indeed, unencumbered by the
means to display synthetic imagery at other times.
And now on to the main body of my idea:
When travelling on the tube, although it is called the London
Underground, in actual fact, the majority of it is not actually
underground, in fact. And consequently the lesser length or
duration of it is underground. However, in Zone 1, most of a
journey is likely to be underground. People may or may not
realise that a tube train that comes into a station
underground will open all doors on the platform side no
matter what, whilst when the train comes into a station that
is outside in the weather, the doors wont all open for you,
you can open them yourself, if the station is overground.
The idea is that the tube trains door windows and indeed
perhaps all windows are, when underground, replaced with a
view of synthetic imagery information, education,
entertainment or perhaps advertising (hopefully not
completely the latter). When underground, theres actually
nothing useful to see out of the windows anyway. When the
tube train approaches the station, underground, people will
want to see out of the windows at the station and people at
the station will want to see in to see where the rare available
seat might be, so the glass will be just a window again, not
displaying and not impeding the vision.
When the tube train is overground, up above, then of course,
people will want to see out. The displays will not have any
effect as synthetic displays, but will be fully transparent as if
they are glass windows. Whether this is achieved by
displaying what the window position sees, or whether it is
achieved by simply switching off the display ability is the
question. I do not believe it is currently possible to actively
display synthetic imagery on a glass substrate whilst also
allowing it to be fully transparent to the point that if the
display were switched off, its just a window.
The not unrelated idea was affixed to the half bakery by MaxwellBuchanan in the meantime. [Ian Tindale, Dec 09 2015]
[hippo, Dec 09 2015]
[xenzag, Dec 09 2015]
Related.... sort of
[Ling, Dec 09 2015]
||It could be done mechanically, by having shutters or blinds that come down bearing the displays.
||The window could be interlaced; alternate thin strips could be transparent, and opaque. When the outside is dark, the opaque strips will be lit up as a display. When the outside is light, the opaque strips will go dark, allowing the inhabitants to view the outer vista.
||Since you only need to display while underground, why not paint the walls of the tunnels with frames of video and make the window a single LCD shutter that strobes in proportion to the train's speed.
||Yes... a Zoetrope Tube. Although this system would be a pain to update with new content, it would have a much lower initial cost. Of course your advertisements would often run backwards or at the wrong speed, but that may add to the entertainment value.
||Having commandeered the windows for ad space, the only things that remain are the floor, and the faces of other passengers.
||mitxela, well actually, I was seriously considering
the ceiling space inside the carriages. On some tube
carriage designs, there really isnt a lot of ceiling
space, but on others, theres a huge amount, and you
wouldnt need this sometimes it goes transparent
thing, you just put ordinary DOOH displays up there
||A google search for "transparent display" shows some options.
||//Since you only need to display while
underground, why not paint the walls of the
tunnels with frames of video and make the window
a single LCD shutter that strobes in proportion to
the train's speed.//
||That bit's baked. Not the shutter, I think the
frames are painted in such a way that persistence
of vision covers it. Zurich airport, shuttle between
the terminals is the only instance I'm aware of, but
I'm sure there are others.
||For display underground you could do it with any
sort of projection system. Since the inside of the
car is better lit than the tunnel, light will reflect.
The real trick would be to make it reflect inward
from a projector that's nearly directly above the
window. I can think of several possibilities, but I'm
not certain if any of them would work without
distorting the window in clear mode.
||I hate to be a damp hamster, but I am opposed to the
idea that there always has to be something to look
at, just as I am opposed to the idea that everything
requires background music.
||See last link..... been there, done that, now all of the counting holes in my sieve collection.
||A completely passive approach is possible (i.e. no need for moving parts or electrical switching).
||Cholesteric liquid crystal have the interesting property of reflecting light in a single narrow band of colour and transmitting all other light/colours. So if you print an image with liquid crystal 'ink' (using three different liquid crystal types which respectively reflect red, green, and blue) on a transparent substrate, then you get two distinct effects depending on the lighting: when viewed in normal ambient light, the image would be invisible because the transmitted light will overwhelm/swamp the reflected light. When transmitted light is removed (when viewed against a dark background) the reflected image would become apparent.
||Applying this to the train window: the image would be invisible when light comes through the train window (i.e. when the train is above ground), but would become visible when the train went through a tunnel.
||Err in a certain country beginning with the
letter J, there isn't the "let's hide the driver
away behind a big metal partition" mentality.
So you can see the driver and watch the track
through the front window. Also, one line has
lights inside the tunnel going the whole route,
so you can check out the infrastructure, trains
coming the other way. It makes the journey a
bit more interesting and less of a just being
stuck in a metal tube underground.
||// I am opposed to the idea that there always has to be something to look at //
||If observation ceased, so would the Universe ... "There is no deep reality; reality is created by observation".
||Suggested categorisation - Vehicle: Subway Train.
||//"There is no deep reality; reality is created by
||Ah, I see how that misunderhension could arise.
It's quite common for physicists to insist that
observation is needed in order to collapse a
wavefunction and force nature to congeal into
||In fact, it's very much the other way around.
observations are a mechanism for reality to
observe physicists, thereby collapsing the
physicists' wave functions. In the absence of
suitable observations, physicists are nothing but
smeared-out probability functions: they believe all
possible things equally.
||Reality will, sooner or later, make things that observe