From: Stuart Biggar (Stuart.Biggar_at_opt-sci.Arizona.EDU)
Date: Thu Jun 04 1998 - 20:17:22 EDT
> From owner-thinkpad_at_cs.utk.edu Thu Jun 4 16:57 MST 1998
> From: letoured_at_sover.net
> Date: Thu, 04 Jun 98 19:55:50 -0400
> To: Bill Morrow <penzance_at_icanect.net>, thinkpad_at_cs.utk.edu
> Subject: Re: Typical TP Price Drops?
> X-Mailer: MR/2 Internet Cruiser Edition for OS/2 v1.40
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> >my GUESS is when there are sufficient machines to fill orders AND
> >competitive pressure, and not likely on the AMD chip
>
> Thanks Bill,
>
> I guess that means the end of the year or longer.
>
> A second questions if you have time; is there a large difference between
> the TFT screens and the dual-scan screens outdoors? --I do a lot of
> writing and some I like to do outside. For that matter is there a big
> performance difference that makes the P-II chip worth the cost?
>
> Thanks for your thoughts.
>
>
>
> --
> -----------------------------------------------------------
> letoured_at_sover.net
> -----------------------------------------------------------
>
>
Hi,
We use notebooks outside to collect data during
cloudless days in the Southwest (Arizona, New
Mexico, Nevada, etc). We have not found a color
display on a normally available notebook that
works very well (most are basically invisible
outside under bright conditions).
The best notebook we have for field data collection
is an ancient HP Omnibook which has a "transflective"
gray scale display (it is not backlit). It works
quite well as does the display on an even older HP
100LX (basically a hand held IBM PC-XT with a small
CGA transflective display). We also have some older
"laptops" made originally for the US military. They
have transflective displays which can be backlit for
night time. The also work well outside but they are
heavy (metal cases) and they were VERY expensive.
Now, you might find some custom "notebook" with an
avionics quality color display but the power consumption
and cost will make you wince!
The real problem is that sunlight reflecting from the
display is brighter than the transmitted backlight in
cases of very bright outside scenes.
Note that the document referenced recently in the thinkpad
group ( http://www3.pc.ibm.com/techinfo/bae6.html ) gives
both contrast and brightness of TP displays (at least it
does for the 770E/ED on the page I printed). You could
compare those figures for a 1st estimate. The real problem
is that the reflectance of the different screens might be
different (depending on the surface treatment) and that
would strongly affect the reflected signal outside (normal
glass reflects about 4% or so of incident light at each
(uncoated) surface (air-to-glass interface). The better
screens have some anti-reflection coating and the type
strongly affects the reflectance (multilayer coatings are
more effective but more expensive and some are easily
scratched).
I wouldn't plan on nice viewing outside if it is bright
(like it is here in Tucson, especially this time of year).
Good luck,
Stuart
-------------------------------------------------------------------------------
Stuart F. Biggar Phone: (520) 621-8168
Remote Sensing Group FAX: (520) 621-8292
Optical Sciences Center
University of Arizona
Meinel Building
PO Box 210094
Tucson, AZ 85721-0094 Internet: Stuart.Biggar_at_opt-sci.arizona.edu
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