Re: [NTLK] High Quality replacement MP2x00 white backlights

From: Johannes Wolf (mp2100_at_mail-gw.estec.esa.int)
Date: Wed Feb 23 2005 - 23:22:04 PST


Sorry to be so late.
I want just to put my two cents into the discussion.
I followed with interest the BL4U project.
One of the lessons learned was that the Newt LCD and the original green BL
are a more or less optimal package, why?
1) the LCD has certain optical properties: one of the most important ones
for the BL issue is the "insertion loss" of the BL for the light intensity
dependent on the frequency (color) of the light. You may remember
photographs showing a lit BL foil stand alone and behind (through) the Newt
LCD. You could see a remarkable loss of intensity through the LCD.
Experiments clearly showed that the original green color is still the best
one with respect to the minimum "insertion loss" for the green light. Keep
in mind here that a brighter light will cost more power and therefore
battery run-time.
Due to the mentioned above filter properties of the LCD the white BL does
not produce a real b/w display on the Newt - you even get the subjective
impression of a less readible display with less contrast compared to the
green BL. Thus -> brightness of the BL is not everything.
2) the original green BL foil can be improved mainly in terms of lifetime by
using state of the art BL foils (as has been the case for the BL4u project).
Due to the different electrical properties of the nowadays foils the BL
driver circuit needs to be adapted in order to achieve optimal results.
3) what you can see on the photographs does not necessarily reflect the
impression you get if you really see it: the CCD sensors also do have a
different sensitivity for different colors.
Thus on the photos the display may appear better than in reality or vice
versa.

Cheers
Johannes

> -----Original Message-----
> From: newtontalk-bounce_at_newtontalk.net
> [mailto:newtontalk-bounce_at_newtontalk.net]On Behalf Of James Wages
> Sent: Monday, February 14, 2005 1:38 PM
> To: newtontalk_at_newtontalk.net
> Subject: Re: [NTLK] High Quality replacement MP2x00 white backlights
>
>
> On 2/14/05 4:47 AM, Martin Joseph <martyNT_at_barknaturalpet.com> wrote:
> >> With today's technology, there has to be a brighter solution
> than what Apple
> >> produced over 8 years ago!
> > Following that logic there would be a better PDA also! Which
> there isn't...
>
> I wasn't making a merely logical or philosophical statement. While other
> PDAs have yet to come up to speed with Apple's software
> implementation, the
> fact is that hardware, including EL technology, has progressed over the
> years. One reason no one has copied Apple's software interface is because
> Apple holds the copyright to it. Apple does not own the patents on EL
> technology, however.
>
> And so, the progression in hardware technology has nothing at all
> to do with
> the Newton interface still being the best out there. My remarks
> are simply
> a means of calling out to the suppliers of Newton backlights to make
> something brighter and hence better than the stock EL. It should be
> technologically feasible to do this, although it may require electrical
> modifications to the EL driver circuitry. But I would be willing to take
> out the soldering iron if it meant a brighter EL -- especially a brighter
> WHITE backlight.
>
> -- James W.
>
>
> --
> This is the NewtonTalk list - http://www.newtontalk.net/ for all inquiries
> Official Newton FAQ: http://www.chuma.org/newton/faq/
> WikiWikiNewt for all kinds of articles:
> http://tools.unna.org/wikiwikinewt/
>

-- 
This is the NewtonTalk list - http://www.newtontalk.net/ for all inquiries
Official Newton FAQ: http://www.chuma.org/newton/faq/
WikiWikiNewt for all kinds of articles: http://tools.unna.org/wikiwikinewt/


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