LG demos transparent LCD | Hacker News Reader

LG demos transparent LCD

justinireland.com

40 pointsjustinireland36 comments

I'm not sure what I'm missing here, but I'm pretty sure transparent LCDs have existed in commercial production for decades. For instance, back in the mid-90s (and possibly still today) they make displays that emulate TI-8x calculators and can be placed on an old-school overhead projector, for classroom use.

I thought all LCD's were somewhat transparent. They have backlights behind them, after all, and LCD projectors are clearly transparent.

TI ViewScreen. :-)

I used to work at TI in the education/productivity group. Know way to much about it that monster. Worked on the model for the TI-Nspire for a bit. Software guy and not a hardware guy so I know very little how it worked.

I'd like to see this paired with an e-ink screen on the next Kindle. Turn on only the e-ink for reading, only the LCD for UI, or both to show highlighting and notes overlaid onto the text. They could use the touch screen to get rid of all those buttons, too.

I think a better scheme would be having embedded OLED dots mingled in around the eInk microcapsules. Then you don't get the degradation you get with layering one thing over another.

Interesting proposal, but impractical. LCDs are transparent as many others people have noted, but transmission efficiency is often as low as 10% (yes, some 90% of the light is blocked). See: http://en.wikipedia.org/wiki/Liquid_crystal_display_televisi...

Aren't all LCDs transparent? Are they demoing anything more than an LCD without a backlight?

It's hard to tell because this write-up is so poor, but my guess from the pictures is that the lighting is much of the actual invention here. Perhaps they've got a technology for uniformly lighting a color LCD without a typical backlight. The display looks uniformly bright and the colors look good, which makes me suspect that they are not merely relying on the background image to provide the "backlight".

Or maybe it's just a completely normal LCD being demoed in front of a cleverly lit diorama. ;)

If you go to a casion, look out for WMS slot machines, specifically this one (Goldfish (the new one, not the old machine)) I played this in Atlantic City at the Trump Taj Mahal downstairs next to the noodle bar and they use a transparent LCD over their spinning reels. Pretty cool stuff.

Demo promotion video: http://www.youtube.com/watch?v=E08IvXQ-rZI&feature=relat...

Edit: A pretty nice in game example of the LCD on the slot in action: http://www.youtube.com/watch?v=2eEyr6y8kNE&feature=relat...

It looks really really cool in person.

Are those actual physical spinning wheels? On the video you can't really tell that it's not just one giant screen, I bet the effect is cool AFK though.

Yes they are actually spinning. If a Wild shows up on the reel, the LCD screen pops a "Wild" animation over it.

Have I missed something, surely this is entirely pointless? You need to have a blank single colour surface behind it, or the images on the transparent screen get obscured by the colours of whatever is behind it. This is even demonstrable in their demo video!

LCDs are supposed to be transparent.

What would be cool is if I could have a sun-powered backlight for my laptop when I want to use it outdoors.

A few 80s home video games used this principal. I had a table top version of Donkey Kong (about the size of a coconut) that worked like this. I think they preceded the single-, double- and triple-screened handhelds (e.g., Diamond Hunt). I don't think it was possible to play that Donkey Kong in the dark and I have a faint recollection of chasing sunspots around the house for the best playing conditions.

They used to use them in PDAs. They're called transreflective LCD [1] displays. They're nowhere near as bright as a backlit LCD though, and only look good when you've got a good light source.

1 - http://en.wikipedia.org/wiki/Transflective_liquid_crystal_di...

I mean, more like light coming from the back through the LCD screen into your eyes, unlike transreflective LCDs.

One needs a white tent pitched behind the laptop screen, and one needs to sit facing the sun. You'd be looking into the space of the tent, which is much like the display in the OP demonstration except the source of light is the sun coming through diffused through the tent fabric (and there are no buildings). The bottom floor could be a mirror.

SUN

       /\
 fab. /  \  <-- laptop LCD
     /    \
    / tent \
    --------======== <- keyboard
     mirror

where fab == white tent fabric

Interesting idea... I don't think I've ever heard of something like that concept before.

I see two problems, though there may be ways to mitigate them: you're facing the sun, therefore it's effectively in your eyes, and you'd probably lose all semblance of color balancing in the screen.

Not that the second is all that important to most people. I've even gotten used to applications like Flux[1] which change the screen's color over the day, and I find it's usually easier on my eyes. Just sayin'.

You could probably do away with the mirror, and just have a white piece of plastic. It'd be diffused by the fabric anyway, there's no need to have something mirror-like to reflect it accurately. You could possibly use the entire back panel of a laptop screen, and fold it up when not in use (brain-farts while looking at my wife's white Macbook).

[1]: http://stereopsis.com/flux/

What you are 'missing' and the folks who watched minority report or Avatar are lusting after, is a transparent piece of material that they can display stuff on.

True, LCDs are, by their nature, transparent. However their contents are only 'visible' when there is light going through them, and they work by adjusting how much light passes through them using polarization. If you have a full spectrum light behind them, and you have red green and blue dots which you use for color selection, you get a color LCD.

However, these don't generate light. And no, nobody has built one of those yet. To build such a display would no doubt require that you build a pixel out of three (or four) LEDs that are nominally transparent, such that turning them on would cause the pixel to appear.

That would then make for a display which was clear, except for where it had data showing. So far, this technology (outside of using a projector to project the display on to a window where the user sees the reflection as the display) does not exist.

1 point by apbitler 0 minutes ago | link | edit | delete

So to the person asking about the slot machines.. they technology behind this is called "multi-layer LCD". I was in Vegas for the CES and I saw these slot machines.. and I couldn't believe my eyes! I did some research and found out that it is actually 2 LCD screens, and one of them.. or both are able to go completely transparent.. thats how you get the 3d effect. Check it out for yourself: http://www.pcworld.com/article/130233/new_slot_machines_prom.... http://www.puredepth.com/technologyPlatform_sw.php?l=en

Just a few steps until I can have my holodeck.

Hey, I've waited since the 90's for my PADD and its finally here, I have no doubt now that my holodeck is not far behind.

I can envision augmented reality applications for something with a smaller form factor and higher contrast. A camera could track the user's relative position, and overlay data about objects in the actual view for the user. If the device could do iris tracking, it could even react to the region of the screen the person is looking at.

The resulting image looked about as unusable as I expected. Besides HUD applications, what is the use case?

I think it is just the standard "hey look at this nifty but completely impractical thing we can do".

For me, behind my monitor is a window because I want to be in an area with lots of natural lighting (I've worked in rooms with no windows, and its no fun, after a while it just gets you down). So a see-through LCD would be a total disaster for me.

Apple used to have a Cinema Display monitor with a see through bezel, the see through LCD would look gorgeous in combo with that, if a little impractical.

Maybe the use case is what it looks like not when it is on, but when it is off? I imagine in this scenario it would be something that you wouldn't use as your day to day computer that you spend hours on.

You could build your LCD into the window, then when you're not using it it doesn't impair the view? Or maybe it is useful for HUDs in cars or other vehicles? Build it right into the windscreen?

(But wait - aren't there cars that already have this? Isn't there a merc with nightvision built into it or something like that?)

I think almost all passenger vehicle HUDs are displays in the dashboard that are reflected off the windshield - I suspect they also sometimes put a lens on it so that it appears to be further away than it actually is, because it might cause major headaches for people to frequently change focus from the road to the windscreen.

I remember test driving a Yaris, which was the first car I'd driven with a digital speedo. That was incredibly distracting, because I kept trying to get exactly on the speed limit. It was actually dangerous.

I drove a Renault with one of these. You get used to it. After a few days, it is no longer distracting. Actually, I found the usual analogue gauges distracting when switching back!

Mercedes now uses a high resolution screen that displays an analogue speedo gauge. That is an interesting combination!

A tablet where you touch the back of the device? Getting the hands out of the way seems a good achievement.

Microsoft Research had a project called Lucid Touch which showed this concept.

http://www.patrickbaudisch.com/projects/lucidtouch/index.htm...

Nothing besides HUDs and ar glasses, that's waay enough. But oled displays would be even better, because this lcd is transperent even where are images.

A scene in a sci-fi cop drama with a "minority report" interface for a police line-up.

I'm confused. The image behind the LCD is clearly not from the LCD (there is a parallax effect), but the background image still seems artificial. Is this just two screens stacked on top of each other?

Pretty sure it's just a little model of buildings in a box right behind the display.

So they've taken a regular screen, added a touch-sensing layer like loads of things have already added, and made it harder to read what's on it. Is this supposed to be good?

If they got it to be self-lit (ie, via the edges), it might be interesting, but it doesn't look to me like that's what it is - it looks like the box behind it is providing all the light. So it is, very precisely, a large, expensive rear-projection display.

Wow. Congrats to the research team, how many DIY LCD hacks did you have to see to realize you could do this?

Yeah, I suppose I deserve the down-vote, too much snark. Apologies! Especially due to this info alok-g linked: http://en.wikipedia.org/wiki/Liquid_crystal_display_televisi... Important bit: 3M suggests that, on average, only 8 to 10% of the light being generated at the back of the set reaches the viewer.

I'd always thought they were more transparent than that, given that I've seen LCD screens used as projectors: http://www.instructables.com/id/DIY-LCD-PROJECTOR/ in which case (though there's no way to detect how bright the box behind it is) a highly-transparent screen could indeed be a fairly significant breakthrough.

[1]: http://news.ycombinator.com/item?id=2267436

these products (as other pointed out) exist for year. they have been sold to use with overhead projectors.

i ones has this old tech-hippie show me one and telling me: with this device you can actually watch television together! (he put the frame in between our faces with it showing some picture, and he smiled -- i saw the picture AND his smile)

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