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Comment by jmcqk6 | Hacker News Reader

I'll be getting the Pixel Qi version, if the reviews hold up. I'm slightly skeptical that the device will meet expectations, but I've already put money back to buy the device as soon as it's available. The Pixel Qi screen alone places it above an iPad.

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Likewise; I think that this will get a huge amount of preorders from people that have just been waiting for any Pixel Qi tablet at all. I can't imagine how they could screw this device up badly enough to warrant me not paying $500 for it. (And they may not screw it up at all; it sounds pretty open, with good specs.)

I'm really happy to see that this is evidently not vaporware.

So I hadn't hear about the Pixel Qi screen. Wikipedia just says

>The company [Pixel Qi] designs liquid crystal displays (LCDs) that can be manufactured using the same fabrication machinery as conventional LCDs. However the Pixel Qi displays are also able to turn off the backlight to save energy, and switch to a low-power black and white reflective mode which can function in ambient light.

Is it correct to describe these as LCD's with a Kindle-style e-ink screen sandwiched on top? Am I wrong in assuming that it has two distinct modes: back-lit color (which is hard to read in bright light) and e-ink B&W (which only works in good light)?

Sounds pretty great.

Yes. The Pixel Qi screen was developed for the OLPC and it works really well. It's also got fast screen redrawing in "e-ink" mode, albeit grayscale.

I have to OLPC XOs. The resolution of that Pixel Qi is impressive, but . . . it looks funny. Like the fine quartz sand on Pensacola Beach.

From what I understand that is exactly what the Notion Ink is aiming for - standard LCD with an Electronic Paper view mode.

I will wait until it's been vetted by my peers before laying out money on it, but I do have high hopes for this one.

FYI: You can actually purchase those screens already from PixelQi

http://www.pixelqi.com/where_to_buy

Not sure if anyone has written up a review on the quality of the screen though. I've seen a few videos of the screen and it seems acceptable.

http://www.display-solution.com/en/products/tft_displays/pix... (video there)

Actually, it can just turn the backlight off. The B&W mode isn't e-ink at all, it's still basically an LCD screen that can be illuminated by external light. So the effect should be the same, but this is the reason I want to wait for reviews to come out before I purchase it. It seems like a perfect compromise to me between e-ink and LCD screens. Sometimes, I want a backlight. If I'm reading, though, I probably don't want it activated.

It doesn't have the same energy-saving properties as e-ink (no power to display, only on page changes). E-Ink also looks different at the pixel level:

http://www.wired.com/gadgetlab/2010/08/pictures-kindle-and-i...

>Actually, it can just turn the backlight off.

There has to be more to it than that, right? It would be trivial to allow LCD screens to turn off the back light.

Their blog (pixelqi.com) suggests that it has to do with some sort of reflective properties of their special LCD. I still don't get it.

Perhaps there is a partially-reflective film on the back of the LCD, but in front of the backlight diffusor, that lets the backlight through (with some attentuation).

The screen is described on the OLPC site: http://wiki.laptop.org/go/Display

As I understand it, it is a standard(?) trans-reflective (like half silvered mirror - it reflects front lighting, but also can be back-lit) black & white LCD.

In color (backlight) mode, the backlight shines strips of color, so the pixels gate the colored light rather than having a white backlight and color filters on the pixels.

In B/W mode, the backlight is turned off (saving quite a bit of power) and the LCD uses the reflective qualities of the LCD to reflect the front light for the lighting source.

The interesting thing is that front lighting will overwhelm and wash out the color from the backlighting as the front lighting gets stronger.

I have an OLPC, which is the predecessor display, and it works quite well. My opinion of the display is that the compromise was visible but not bad: the color definitely isn't as vibrant as a traditional color LCD or OLED, but the daylight view-ability was very good vs. a traditional backlit LCD that becomes poor or unreadable in bright sunlight.

There are some pictures on the Groklaw article, although I was focusing on size rather than the display when I took the pictures. In retrospect, I should have focused on the display more than the size. :-/ http://www.groklaw.net/article.php?story=20080128171935946

> Is it correct to describe these as LCD's with a Kindle-style e-ink screen sandwiched on top?

Not quite. E-ink is a different technology[0]; this really is a form of LCD [1], albeit one that has somewhat different reflective properties. That said, I've got an OLPC laptop and was stunned at how legible they were in full sunlight---very impressively different from your typical laptop screen. (E-ink is still better; it has much more of a "writing on paper" feel. But it's slower.)

[0] http://en.wikipedia.org/wiki/E_Ink

[1] http://en.wikipedia.org/wiki/Pixel_Qi, although it's clear that the parent already saw this

Wow, thanks, this is the answer I was looking for. So do the colors still look mostly the same in bright sunlight, or does the screen become more B&W?

I have one of the OLPC XO-1 units in my hands. When the backlight is on, it's still readable under very bright light such as sunlight and will look like the kindle's black & white.

When you turn the backlight to zero, it switches to ultra-lowpower hi-res black & white sunlight readable mode.

It's pretty neat and something I hope to see in all future devices.

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