Self charging phones aren't that far away • Hacker News Board

Re: Self charging phones aren't that far away

#11

Post by [deleted] » Thu, Aug 11, 2011, 9:34 AM UTC

jbri wrote: post #10

nodata wrote: post #4

"By using polarizing organic photovoltaic cells, however, the LCD-packing gizmo can recycle its own lost backlight energy, keeping itself charged for longer." - wouldn't it be better to make the LCD not lose 75% of its energy?

That would be neat. But it's essentially impossible with a traditional LCD screen - the physics don't work that way. The way a backlit LCD works is that the backlight produces light, which goes straight into a polarizer. That polarizer absorbs 50% of the light energy - if it absorbed any less, then the light wouldn't be polarized. Then the light passes through the liquid crystal element to another polarizer, which ei…

[deleted]

Re: Self charging phones aren't that far away

#12

Post by AndrewDucker » Thu, Aug 11, 2011, 9:42 AM UTC

artursapek wrote: post #6

AndrewDucker wrote: post #5

Earlier quoted context omitted.

Adblock!

I have it! It didn't stop it!

How bizarre. I don't get any ads on that page. (Firefox 5, Adblock Plus)

Re: Self charging phones aren't that far away

#13

Post by StavrosK » Thu, Aug 11, 2011, 9:53 AM UTC

artursapek wrote: post #8

donaq wrote: post #7

Eh, if I understand correctly, it's not self-charging. It just discharges slower.

"What's really cool is these cells can recycle indoor or outdoor light as well..." It's self-charging at a rate perhaps slower than the rate at which is discharges, for now, but it is effectively charging itself. The question is does it break even?

Even if it does not break even, I would be more than happy with double the use time of my mobile. Of course, it would be even better if I just never had to charge it, but baby steps.

Re: Self charging phones aren't that far away

#14

Post by tluyben2 » Thu, Aug 11, 2011, 9:59 AM UTC

It's always great to read, shame it takes years and years to get to market. And I guess this would apply to all LCDs; would laptops benefit much; their screens are also pulling a lot of battery right?

Re: Self charging phones aren't that far away

#15

Post by jules » Thu, Aug 11, 2011, 10:19 AM UTC

jbri wrote: post #10

nodata wrote: post #4

"By using polarizing organic photovoltaic cells, however, the LCD-packing gizmo can recycle its own lost backlight energy, keeping itself charged for longer." - wouldn't it be better to make the LCD not lose 75% of its energy?

That would be neat. But it's essentially impossible with a traditional LCD screen - the physics don't work that way. The way a backlit LCD works is that the backlight produces light, which goes straight into a polarizer. That polarizer absorbs 50% of the light energy - if it absorbed any less, then the light wouldn't be polarized. Then the light passes through the liquid crystal element to another polarizer, which ei…

Beam splitting polarizers split the incoming unpolarized beam into two polarized beams, or more commonly into one polarized beam and another somewhat polarized beam. By stacking many of them you can obtain a polarizer that loses less than 50% of the light.

http://en.wikipedia.org/wiki/Polarizer#Beam-splitting_polari...

Re: Self charging phones aren't that far away

#16

Post by flocial » Thu, Aug 11, 2011, 10:24 AM UTC

Powered by cold fusion? This is similar to eneloop batteries I suppose where the energy circulates back in. Self-charging anything would change history.

Re: Self charging phones aren't that far away

#17

Post by Someone » Thu, Aug 11, 2011, 10:30 AM UTC

jbri wrote: post #10

nodata wrote: post #4

"By using polarizing organic photovoltaic cells, however, the LCD-packing gizmo can recycle its own lost backlight energy, keeping itself charged for longer." - wouldn't it be better to make the LCD not lose 75% of its energy?

That would be neat. But it's essentially impossible with a traditional LCD screen - the physics don't work that way. The way a backlit LCD works is that the backlight produces light, which goes straight into a polarizer. That polarizer absorbs 50% of the light energy - if it absorbed any less, then the light wouldn't be polarized. Then the light passes through the liquid crystal element to another polarizer, which ei…

A better solution is to have the backlight directly produce polarized light. If you do that, you do not need the first polarizer that blocks half the light. There is hope that that is possible. See http://www.semiconductor-today.com/news_items/2010/OCT/RPI_2...

Re: Self charging phones aren't that far away

#18

Post by hristov » Thu, Aug 11, 2011, 11:01 AM UTC

nodata wrote: post #4

"By using polarizing organic photovoltaic cells, however, the LCD-packing gizmo can recycle its own lost backlight energy, keeping itself charged for longer." - wouldn't it be better to make the LCD not lose 75% of its energy?

Yes, but doubtful for an LCD. An LCD should lose at least 66% of its energy in the best case by virtue of how it works. It essentially works by sending out white light and blocking selective spectra of light for each pixel. So even if a pixel is lit up, it should still be blocking or filtering most of the light that hits it and only letting through its particular color.

The better solution is to use LEDs or OLEDs. These do not require a backlight or any blocking but just generate the necessary color of light (and only the necessary color of light) from scratch.

Re: Self charging phones aren't that far away

#19

Post by jodrellblank » Thu, Aug 11, 2011, 1:00 PM UTC

flocial wrote: post #16

Powered by cold fusion? This is similar to eneloop batteries I suppose where the energy circulates back in. Self-charging anything would change history.

Self charging as in not needing an external power supply? I guess history changed in 1986 then.

http://www.seiko.co.uk/technology/kinetic

Re: Self charging phones aren't that far away

#20

Post by artursapek » Thu, Aug 11, 2011, 8:16 PM UTC

StavrosK wrote: post #13

artursapek wrote: post #8

Earlier quoted context omitted.

"What's really cool is these cells can recycle indoor or outdoor light as well..." It's self-charging at a rate perhaps slower than the rate at which is discharges, for now, but it is effectively charging itself. The question is does it break even?

Even if it does not break even, I would be more than happy with double the use time of my mobile. Of course, it would be even better if I just never had to charge it, but baby steps.

Exactly.