Re: Display on CD, CE, CX

["Robert George" <george@holmes.cs.nps.navy.mil>]

On Aug 29,  1:39pm, Robert Dewar wrote:
> Subject: Re: Display on CD, CE, CX
> "> I cannot see any difference whatsoever in brightness between a 755C and
> > a 755CX, they look identifical in this respect (and are sitting side
> > by side).
>
> They *are* different, or IBM is going to be up for a false advertising
> lawsuit:"
>
> Read what I said, I compared brightness, nowhere do
>
> "Of course the other unthinkable possibility is that TFTs vary so much
> in quality that you can't be sure if you'll get a bright or dim one."
>
> Well to summarize this thread, someone claimed that the TP screen was
> significantly dimmer than a PB screen. I contested this. Later the
> original poster noted that he had been comparing the screen in economy
> battery mode w
>
> > Read what I said, I compared brightness, nowhere does IBM say or hint
> > that the new screens are brighter, and they are not. Actually if anything
> > glare reduction can diminsh brightness, although I do not see that.
>
> Yeah, sorry, I noticed that right after I sent it.  What may be happening
> is that people are comparing the screens under different lighting.
> Sometimes the anti-glare makes the TP look brighter, sometimes they're
> the same or the Powerbook is brighter (they *are* advertised as backlit).
>
> Of course the other unthinkable possibility is that TFTs vary so much
> in quality that you can't be sure if you'll get a bright or dim one.
>-- End of excerpt from Robert Dewar

I believe Robert is correct here -- I'm pretty sure that the 755C/CD/CE have
the same Toshiba 10.4" TFT's, with the CD/CE's panels having a glare coat. The
color depth has nothing to do with the panel -- TFT's are analog panels, so
they are capable of an inifinite number of colors.  The color depth is
determined by the number of bits in the RAMDAC's in the LCD controller chip,
and the amount of video ram allocated for the panel.  So the 755C has an 8-bit
LCD controller, where the 755CD/CE have 16-bit LCD controllers, but they have
the same TFT panel.

What is especially suspicious is that the resolution and contrast ratio is
identical on the 755C/CD/CE panels -- while the next generation panels, such as
the Toshiba panel on the 755CX, has 800x600 resolution, and a higher contrast
ratio.

Also, since Sony manufactures the Thinkpad, the Powerbook, and the Dell
Latitude, I would be surprised if they didn't all have identical TFT's within
the same generation products.

Robert George
Army Research Laboratory