Apple has just filed a patent for an in-screen / device-covering solar film for its gadgets. We've seen similar in-screen technology patented by Motorola already (not clear if this is an infringement), but Apple wants to cover the entire device, not jut the screen, with the solar cells.

You can already get a solar powered iPod -- it just requires a larger-than-an-iPod charger that you have to lay out in the sun all the time.

Not perfectly convenient, for sure, but I suppose it's better than the regular coal-powered way of charging up. But if the solar cells were built into the device, that would certainly make things simpler.

Unfortunately, with current efficiencies for thin-film solar (the only kind that could be semi-transparent), it's unclear that there would be much benefit. Unless you were planning on leaving your iPod in the sun all day long, you'd still need to charge the old-fashioned way.

Unless Apple starts making flat gadgets with a large surface area ... and that doesn't seem to be the direction the company is going.

For those of you with the 3G, you may have noticed an issue with a rather short battery life. Well, Mobilefun has a solar-powered case that will help you with that problem.

The solar case can provide enough charge for functional use in less than 3 hours, but it will take a full 10 hours to fill the battery. Maybe the thing to do is leave the case on the dashboard or window sill all day, then charge your phone up at night.

The case uses a solar panel to soak up sun, holds generated energy in a 1500 mAh battery, and then charges up your phone when you insert it. If there isn’t enough sunlight for a good charge, you can also use a mini USB; but if that’s the issue, you might as well charge your phone the old-fashioned way.

The solar case is compatible with all iPhones, so if you have an older model, you can still get your time in the sun.

Perhaps this is coming out a little late for Matthew Sparkes to test out, so we don’t know how well it will work yet. I’m sure there will be reports on its effectiveness after it hits the market in mid-August.

But every little way to use renewable energy is a step forward. And this way, you don’t have to wait for the price to drop on the solar cell phone.

Why the heck not right? I mean, YoYos are a very efficient way of generating power, and iPhones don't really need all that much power to charge. So what's the problem with this idea?

I'd even say that it's several times cooler, more convenient, and better for the environment than a solar-powered charger.

What remains to be seen is whether or not you can actually get enough power out of one of these things to charge your phone easily. And no one wants another thing to carry around. Which makes me think ... why not just put the phone inside the YoYo!

Inhabitat is treating this thing like it will actually exist soon, but I'm not so sure about that. It seems like a pretty design project to me ... a joke even. Big cues that it's not coming to market any time soon include the Apple logo on the device (which would never be allowed for a real design project.)

But that doesn't mean it's not a good idea. And we certainly hope that this and other human-powered charging devices will make our mobile future more convenient and more sustainable.

We stopped reporting on solar battery chargers a while back. It just seemed to me like a sub-optimal use of solar technology. I mean, for the most part, the panel sits around doing nothing. And it's not like battery charging uses a really significant amount of the world's energy (though it's certainly growing).

But for those of you who have your hearts set on charging your batteries with the sun, the big guns have just joined the game. Energizer, who employs a bunny that is, apparently, fusion powered, is debuting a solar battery charger at CES in January.

The device will power charge AA or AAA batteries, and has a USB port for charging cell phones and iPods and the like. The weatherproof design hints at its true use, charging up while beyond the reach of civilization.

Because, really, what's the point of back-country hiking if you can't watch YouTube videos on your iPhone while you're out there.

I have a thing for all-in-one gadgets. I admit that the more I can consolidate must-haves into one item, the happier I am -- from my printer-fax-scanner-copier to my phone-palm-alarm-MP3-player-does-everything-but-cooks-dinner, I like being able to do everything without having a bunch of stuff surrounding me.

So this Media Street eMotion Solar-Powered Media Player and Charger looks appealing as a media device.

Priced at just $169, this gadget is a photo album, music player, game player, e-reader, and charger. It plays ROMs, MP3s, and MPEG4s, and it charges lithium battery-powered gadgets while its at it. The device only holds 2GB, but the fact that it is solar powered forgives the relatively small memory capacity. And it is far more practical than the James Bond-ish Pen Camera.

But, surprisingly, the specs on the solar power capabilities aren’t readily available, even at Media Street’s website, which makes me think the solar charger part is one of the weaker elements.

Doesn’t that just figure … but it is probably better than wind-up toys.