Innovative solution for e-Ink screen lighting

[JD Gumby]

Originally Posted by HarryT

I completely agree - that's why I specifically said "at the same level as the ambient light in the room". The problem is that many LCD devices either don't allow you to adjust the brightness, or else the user sets the brightness too high. If you set the brightness correctly, there really is no physical difference between the LCD and the eInk screen as far as your eye is concerned.

Unless, of course, the refresh rate is too low... (for example, I can only read on my LCD monitor at the default 60MHz for a few minutes at a time before the eyestrain starts showing up - a problem which goes away when I go up to 75MHz; annoying 'cos this monitor's highest rez, 1440x900, can only be used at 60MHz

[HarryT]

Originally Posted by JD Gumby

Unless, of course, the refresh rate is too low... (for example, I can only read on my LCD monitor at the default 60MHz for a few minutes at a time before the eyestrain starts showing up - a problem which goes away when I go up to 75MHz; annoying 'cos this monitor's highest rez, 1440x900, can only be used at 60MHz

But an LCD screen doesn't "flicker" - why should the refresh rate matter? It's a "steady" image. I'm not doubting what you say; I'm just curious why it should matter, as you say it does for you.

[elcreative]

Originally Posted by HarryT

I completely agree - that's why I specifically said "at the same level as the ambient light in the room". The problem is that many LCD devices either don't allow you to adjust the brightness, or else the user sets the brightness too high. If you set the brightness correctly, there really is no physical difference between the LCD and the eInk screen as far as your eye is concerned.

But for many uses, having the computer screen at ambient light levels is absolutely useless... for starters, no calibration for design colour to print work... screen at ambient levels gives wrong balance by a huge margin... it doesn't matter how adjustable your brightness is, if the level you adjust to, is wrong for actually doing any work...

[HarryT]

Originally Posted by elcreative

But for many uses, having the computer screen at ambient light levels is absolutely useless... for starters, no calibration for design colour to print work... screen at ambient levels gives wrong balance by a huge margin... it doesn't matter how adjustable your brightness is, if the level you adjust to, is wrong for actually doing any work...

I absolutely agree with you. But if you get eye-strain from LCD screens, how to do you use a normal computer monitor? Are you not reading this on an LCD screen? Is it simply a matter of taking regular breaks from the computer?

[JD Gumby]

The lack of flicker on LCD screens is a marketing myth, as pretty much anyone who actually uses one can tell you when they get eyestrain at lower refresh rates.

[HarryT]

Originally Posted by JD Gumby

The lack of flicker on LCD screens is a marketing myth, as pretty much anyone who actually uses one can tell you when they get eyestrain at lower refresh rates.

It's not - it's a matter of physics. A pixel on an LCD screen does not repeatedly dim and need to be refreshed again, as the phosphor on a CRT does. The backlight behind the screen is shining with a constant brightness - it's not flickering. They used to flicker, in the "old days" when LCD screens had fluorescent backlights, but these days LCD screens have LED backlights, which have a constant light output.

[elcreative]

Originally Posted by HarryT

It's not - it's a matter of physics. A pixel on an LCD screen does not repeatedly dim and need to be refreshed again, as the phosphor on a CRT does. The backlight behind the screen is shining with a constant brightness - it's not flickering. They used to flicker, in the "old days" when LCD screens had fluorescent backlights, but these days LCD screens have LED backlights, which have a constant light output.

But the pixel does change at the refresh rate, otherwise you'd have a static image... the light doesn't come from the pixel, it is transmitted through it... and the pixels vary at the refresh rate to give a variable picture... the screen is refreshed at the refresh rate (60, 75 whatever per second) and, whilst the screen doesn't blank between refreshes as CRT did, it still changes at that rate per second...

[HarryT]

Agreed, and that can certainly be a factor for such things as games, where a high refresh rate is desirable. But when you're simply reading, the image is static, other than when you change the page, so why should the refresh rate matter then?

[Sil_liS]

Originally Posted by HarryT

If you set the brightness correctly, there really is no physical difference between the LCD and the eInk screen as far as your eye is concerned.

But it is your brain that forms images from what the eyes see. Considering the fact that to automatically interprets a change in focus, flips the image and is able to make us ignore missing images when we are blinking, it might have to work harder to figure out how an image from a light source if put together compared to an image from reflected light.

Originally Posted by HarryT

A photon is a photon. Your eye doesn't "care" whether it's emitted by the screen, or reflected from it. A light-emitting screen which emits the same level of light as the ambient light-level of the room, is absolutely indistinguishable from a screen which operates via reflected light, as far as your eye is concerned. Anyone who claims otherwise really has no understanding of elementary physics .

Except that the spectrum will differ between backlit and reflective displays. I don't know if this is enough to give people headaches, but the nature of the light received from transmissive and reflective displays is fairly different.

[Rizla]

Originally Posted by HarryT

A photon is a photon. Your eye doesn't "care" whether it's emitted by the screen, or reflected from it...Anyone who claims otherwise really has no understanding of elementary physics .

That's a ridiculous comment. LCD actively emits light, E-ink does not. Try looking at a light bulb when its on and then when its off, and see if your eyes notice a difference.

[Kumabjorn]

Originally Posted by Rob Lister

I have a much simpler solution to the back-lit ebook conundrum. Simply add a thin layer of radium to the underside of the screen. This would accommodate reading in pitch dark.

I'd personally implement this idea but but wacko-environmentalists, meanie-greenies, the NRC, FDA, and probably even Underwriter's Labs would all gang up on me. PETA would probably be okay with it though.

Me like this idea. How radioactive would something like that be? If i calculate that I have 30 years left to live, would that level have any direct impact on my potential life expectancy?

[toddos]

Originally Posted by elcreative

But the pixel does change at the refresh rate, otherwise you'd have a static image... the light doesn't come from the pixel, it is transmitted through it... and the pixels vary at the refresh rate to give a variable picture... the screen is refreshed at the refresh rate (60, 75 whatever per second) and, whilst the screen doesn't blank between refreshes as CRT did, it still changes at that rate per second...

Nice red herring, but doesn't apply to reading text. Once a pixel is on, it's on. Unless your text is swirling about the screen, it's not going to flicker. Maybe there's the source of your headaches, trying to read moving text?

Edit: I quoted the wrong post. Oops

[pdurrant]

Video on YouTube of Flex Lighting protoype (via the ebook reader blog.)

[Dulin's Books]

thanks