Goodbye Bifocals — Electronic Glasses Change Focus

kkleiner writes "Move over Ben Franklin, we finally have a replacement for bifocals. Virginia-based Pixel Optics has developed a composite lens that can change the range of focus electronically. The emPower! glasses were created in cooperation with Panasonic Healthcare, and allow you to switch between long distance and short distance vision in a split second. Rather than having a lens divided into two sections, emPower! uses an LCD overlay that can change the focal length of the glasses via electric current. When the LCD layer is off, your lenses are good for intermediate/long distances. Turn the LCD layer on, and a section of the lens is suddenly magnifying close-up images – perfect for reading."

Meh.

[msauve]

The Superfocus [superfocus.com] ones look much more interesting (continuously variable focus), and are considerably cheaper, too (~$700). Con: they're only available with circular lenses. Pro: they're hyped by Penn Jillette.

How does that work? I don't even ...

[goodmanj]

OK, here's me. I'm a physics professor. I don't do optoelectronics research, but I do teach optics sometimes. I'm pretty savvy about electricity, magnetism, optics, chemistry, etc. I know how LCDs work, in detail.

WILL SOMEONE PLEASE EXPLAIN HOW THESE SUCKERS WORK? IT'S DRIVING ME CRAZY!

How the hell do you change the index of refraction of a material for *both polarizations* simultaneously? Liquid crystals are birefringent, but that's not enough to make a *lens*.

Also, what does it say about Slashdot and the rest of the geek community websites reporting this story that nobody else is asking this question? Aren't you guys supposed to be curious about how things work, or have you become like the rest of humanity, taking technology to be a miracle handed down from on high?

I'm baffled on both counts.