[ExI] [Tech] Goggles, or Projectors?

[Eugen Leitl]

On Wed, Jan 02, 2008 at 08:28:23PM -0500, Gary Miller wrote:
> What about the possibility of a transparent LCD or OLED on a pair of contact
> lens.

What about the index of refraction (those pesky laws of optics), and providing 
a highly mobile device with a source of power? Sure, you could wear goggles 
with solenoids in them. Connected to the the heavy battery belt.

Or you could simply wear a HUD. Microoptical used to have really good prototypes
which were indistinguishable from some designer specs. I notice they no longer
offer these but lots of consumer crap since they renamed themselves to myvu.
 
> The contact lenses wouldn't have to be prescription.

For small opening angles, current optics is good enough. For large
opening angles (unless you want to wear some 10 kg of hardware on
your head -- I did that once) you need custom (lightweight) lenses
and mirrors. A dark horse is a retina laser scanner -- I personally don't
understand how they manage to hit a highly mobile high-curvature object
consistently -- assuming they can at all (I'll believe it when I wear
one). Of course the lunatic fringe is faking the complete wavefront,
using phased array optics (nobody has built one even for IR yet).
 
> For example take the OLED in MobyBlu Cube 2
> http://web.mac.com/mobiblu/Site/Cube2.html
> 
> It's almost small enough and I bet they don't push the resolution because
> the display is so small.

OLEDs are indeed interesting. If we look back in the archives, we'll see
probably a decade during which OLEDs have been interesting.
 
> So upping the resolution would be the most important thing the image already
> is very bright and the current required to display the image is very small.

Where does the power come from?
 
> Light coming into the eye could provide the energy for the display through a
> transparent solar cell  that ran on light outside of the eye's visible

Have you ever seen a completely transparent solar cell? One that looks
like a piece of clear (not brownish, or grey) glass?

> spectrum. 

Let's say we need some 1-5 mW light output. Emitter efficiency is some 10-20%,
PV NIR efficiency is some 20% (let's be generous), you do realize that long-wave
photons carry less energy, and of course there's almost no NIR indoors. Then
you'd need a broadband signal, which would have to be wireless.

Notice something? (Hint: look up the solar spectrum, and crunch the numbers).
 
> The input feed could come from a belt unit that would transmit the actual
> video signal.
> 
> The wireless receiver would have to be on a very small chip though to
> prevent an annoying black area in the corner of the image. When optical
> circuitry becomes feasible you could probably make the circuitry mostly
> transparent since the fibers would be made of glass.

Fibers?
 
> An up down detector would need to transmit a signal back to the belt unit if
> the contact rotated slightly in the eye so that the belt unit would know how
> to adjust the image and make up always up and the image level. 
> 
> The belt unit could present two slightly different images to the left and
> right eye allowing for a true 3D display.
> 
> Blinking three times in rapid succession could even be you on and off switch
> or you could just give a voice command to the belt unit. 
> 
> I want one!

This isn't Slashdot, you know. When you try speculative technology, you
have to be at least borderline realistic about it.

No doubt a device that this will be eventually built, but not using today's
technology. (I really like Vinge, but you must always look when his realism
is superceded by artistic freedom, in order to not ruin a good yarn).

-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
______________________________________________________________
ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org
8B29F6BE: 099D 78BA 2FD3 B014 B08A  7779 75B0 2443 8B29 F6BE