Flexview displays - 6/18 bit or 8/24 bit?

T4x series specific matters only
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noetus
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Flexview displays - 6/18 bit or 8/24 bit?

#1 Post by noetus » Tue May 22, 2007 10:57 am

I've just been reading about theclass action lawsuit against Apple regarding the "millions of colors" that they claim their MacBook/Pro displays are capable of. That implies the screen is 8 bit per R-G-B pixel (16 million colors total) but in fact, apparently, their displays are 6 bit and use dithering to create the illusion of more colors. Does anyone know what the implications of this are for Thinkpad displays? Users complain of "sparkly" screens on their MacBook/Pros, just as some people have complained about "sparkly" IPS panels on T4xp and T6xp machines. Are Flexviews using dithering, too? Are any Thinkpad displays the full 8 bit? (It's striking how rubbish LCD displays are, in general, isn't it? I can't wait until this is outdated technology.)

I've searched the forums but couldn't find any postings about this - perhaps I'm not using the right keywords.

Incidentally, the guy on that ArsTechnica post who (jokingly) implies that LCD screens "only" really display 3 colors, R,G,B, and create the illusion of more (and is therefore off to file another lawsuit) is using an argument that wouldn't hold up in court, as far as I can tell. Transmissive displays use Red, Green, Blue to CREATE colors since those are the physical components of colors in actual fact - in the physical world. The dithering of 6 bit displays doesn't CREATE any colors, it TRICKS the eye into perceiving more colors than are really there via a sort of optical illusion. Quite a different thing. Someone should have pointed that out on the thread. And since the de facto way of quoting the technical capabilities of displays in the computer industry has always been "x number of colors" = "so many bits used in the component colors" Apply does seem to be at fault here, if not de jure, then at least de facto.

Troels
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#2 Post by Troels » Tue May 22, 2007 3:38 pm

It is quite unclear from the IDtech datasheets if dithering is used. Other manufacturers didn't even bother to make a datasheet.
As it is written there it seems to be 262K only.
See http://www.idtech.co.jp/en/products/pdf ... U3-L06.pdf for example.

It's not meant as a personal insult as i know lot's of great and smart persons with Macs - but it's just useless people like that who turns the market sour and make peers pay for it in the end.
Furthermore they are lacking lots of basic facts.

TN screens, are mostly advertised as 16.2M, which is 6 Bit per color + FRC.

A few reasons behind this is:
For desktop LCDs, it's because it is cheaper to use a 6 bit data drivers. People want large, cheap TFTs.

For notebooks, they only use one or two backlights, with a brightness and color spectrum usually lower of what you can do with desktop LCDs. Also more backlights and data drivers consumes power and more space, which is not good in laptop formats. You can't much of the extra color information with the current backlights.

The screens can, if the color gamut of the backligt is high enough, display much more than the 6 or 8 bit, but because of forced limitations it isn't done.

Hence, i guess this is why the IPS screens for notebooks are 6 bit too.

The sparkly issues with a lot of LCDs happen because of the polarizer structure. It might be solved if one chooses a panel from a different manufacturer, or a different model (with glossy surface).
This is extremely easy to test using colors which are defined in the 6 bit range. :)

To be quite frank, i can't wait til TN is completely phased out and manufacturers let's one choose what to have. TN is a disgrace to image quality. IPS and S-IPS should be developed further, but we are in a world where everyone wants the cheapest hardware :)

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#3 Post by noetus » Tue May 22, 2007 4:41 pm

Well, thanks for this, if you're right then it seems the Apple lawsuit is a bit silly. It's not like they're doing anything different from other notebook manufacturers.

Also, if it's really so hard to tell whether the drivers are 6 bit or 8 bit - you can only tell by looking at the manufacturer's datasheet - how can it matter very much?

On the other hand, there must be some way of measuring what the *effective* numbers of colors, gamut etc is for a given panel. That would seem to be the relevant thing.

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#4 Post by Troels » Tue May 22, 2007 5:18 pm

Well, i think it's wrong that the flexviews or any other laptop LCD is advertised as 16.7M. But it's a little surprising that the lawsuit comes now, when this has been (bad) business practice for 8-10 years or so.

I don't think it matters very much when all comes to all. The important thing is how well the percieved color is compared to the reference value.
I agree, it would be a very relevant thing to have, and some sites actually measure the color gamut along with the color balance, at different shades of gray. Only few do...

Here's a review of the MBP 17" with color balance and gamut measuring (at the middle of the page):
http://www.notebookcheck.com/Test-Apple ... 889.0.html

And one of the R50p with a 15" flexview uxga:
http://www.notebookcheck.com/laptop/con ... ew/745/65/

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#5 Post by nutjobox » Tue May 22, 2007 5:25 pm

no kidding since when is this a big deal? how about we sue drive manufacturers for claming 400GB on a truley 360gb drive? lcd's across the board have notoriously claimed more colors then they actually are. hell i know for sure most lcd's arent true 8bit

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#6 Post by richk » Tue May 22, 2007 6:37 pm

I started counting and lost count after 276,233 colors. Maybe I'll have a big cup of coffee in the morning and try again.

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#7 Post by noetus » Wed May 23, 2007 6:26 pm

The issue with hard drives is different. If you look at spec sheets, manufacturers ALWAYS state that 1GB=1,000,000,000 bytes. And everyone knows this, because everyone reads the spec sheets, and so everyone knows what they're getting. They're not diddling us, but defining terms differently, no matter how irritating this is. Not so with these displays. On what justification can they claim 8-bit when it's really 6-bit AT ALL? Why not 6.9-bit? or 7.2 bit? If it's dithering 6 bits, I simply don't see what equation says that that's effectively 8 bits. And since it is so hard to verify what the hardware is doing, apparently (no-one seems to know unless they publish spec sheets as a few manufacturers do, notable ID Tech), then they are effectively pulling the wool over our eyes.

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