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[BeckyJ]

". . .The most interesting technique described by Apple, however, is the integration of the solar panels behind the actual LCD screen of a portable device. The solar panel would absorb ambient light that passes through the LCD screen of the device. This could eliminate any additional footprint typically required by the solar panels. . . ."

http://www.macrumors.com/2008/05/26/solar-lcd-powered-ipods-iphones-and-laptops/

Impressive!

Might such technology find its way to XO-2?

[teapot]

Considering that the whole point of LCD is to absorb, pass or reflect light, a solar panel placed behind it won't see much light unless the screen is displaying google.com or blank page in a text editor. It would make more sense if I read it wrong, and they intend to place a solar panel on the other side of the lid, however it will still work pretty poorly considering that screen is usually close to a vertical position while solar panels are most efficient when placed at a right angle to the light.

I can see solar panels being used to reduce the rate of batteries' discharge, however I expect that Apple users will mostly benefit from light coming from artificial sources being absorbed by those panels.

[Tortuga]

Given that the average coverage of a printed page is something like 6%, that leaves over 90% for solar activity. Even with heavy graphics, something like 50% of the are could still be available for solar activity. For examples of % coverage and what it looks like see the pdf file here: http://www.lexmark.com/uncomplicate/sequentialem/home/0,7070,204812589_1182931731_0_en,00.html

Also given some of the new materials that allow for "electron avalanche", on slashdot today, the efficiency of solar cells could increase significantly.

[GregYohn]

Hello!

Its good to get a reality check from time to time.

Based on $.18 a KW for electricity that I have here in Philly, a $100 cost for a 15 Watt Solar Panel or laptop with a built in $100 solar panel, and the charger for the XO using about 20 watts of power. Me and another XO user did the math and found out it would take 13yrs and 4 months years of use to have the $100 solar panel investment pay us back. We avoided counting other uses of the solar panel, so if you want to get one, then plan to use it for other charging purposes!

Realistically, the solar panel built into the screen might be 5 watts of power, which can not even recharge the XO sufficiently.

Here's the math: I expected 40 hours a week to charge the XO, but if you did it less often then the years needed to pay back the investment would increase accordingly. I did not include the price of a battery to hold the solar power, but you can see that would create even more higher costs.

50 hours of charging costs $.18 1000 watts/20 watts.
$.18 KW goes into $100 about 555 times.
50 hrs * 555 = 27,750 hours.
27,750 hrs. / 40 hrs a week = about 694 weeks
694 weeks is about 13yrs and 4 months.

[teapot]

Given that the average coverage of a printed page is something like 6%, that leaves over 90% for solar activity. Even with heavy graphics, something like 50% of the are could still be available for solar activity. For examples of % coverage and what it looks like see the pdf file here: http://www.lexmark.com/uncomplicate/sequentialem/home/0,7070,204812589_1182931731_0_en,00.html

Also given some of the new materials that allow for "electron avalanche", on slashdot today, the efficiency of solar cells could increase significantly.

Printed page is not the same as a screen -- GUI elements usually have to be dark to be noticeable, and low-resolution text with antialiasing covers higher percentage of the screen than printed text with its thin, high-resolution fonts. I guess, you may get something approaching usable in e-book mode, but high-contrast GUI with large icons used in most of activities would turn solar cell into a useless layer that does nothing but reducing the contrast (thus requiring a brighter backlight in a regular "indoor" mode).