Friday, January 28, 2011

It's Science! | Polarized Lenses 101


What is a Polarized Lens, and how does is work?  Buckle up folks because the CATEYE Science Guy is about to drop some knowledge on you.

Here comes the Sun, doo doo doo-doo… 

The Sun shines down upon us.  As it does so, its light encounters the various surfaces in our modern and natural worlds and is reflected and scattered into a million directions.  This tricks your retinas—glare.

Enter the Polarized Lens.


the What
Polarized lenses reduce glare from reflective surfaces such as the surface of a lake or the hood of a car—or water molecules floating over a majestic meadow.




the How
Pretend your eyeball is behind that lens, and you're trying to check out that righteous wave.  Problem is that some pesky light from the Sun hits said righteous wave and scatters in all directions, trying to confuse your retinas.  Some more pesky light is coming off the sun itself, also trying to confuse your retinas.  The filter inside the Polarized Lens reflects the pesky light, but allows the light being reflected off the righteous wave (blue arrow) to pass through, allowing your retinas to drink in the glory of the righteous wave.

Think of the Polarizing filter like Venetian blinds...



and light like raw lasagna noodles (deliscious)...




If the noodles go straight at the blinds, they'll get through.  If not, then they won't.

Here's a more science-y picture to illustrate this point:


Some limitations...
Polarized lenses do not provide universal protection from glare, however. If you tilt you're head past 45° or so, some of the horizontal light can enter, causing bright spots.

Polarized Lenses can cause dark spots on liquid crystal displays (LCDs). On-board clocks,  some cell phones, navigation screens, and some instrument displays may be slightly less readable.

Polarized Lenses can not be clear—the filters only come in grey or brown.  Recent advances in the technology have yielded lighter filters.  At CATEYE Spectacles we can, of course, make you prescription or non-prescription sunglasses in the classic dark grey or brown, but for a little more fun we can take these new fangled, lighter filters and tint them to create a custom pair of lenses just for you.  We had the lab whip up some examples—these could be solid or even in gradient!  That's something that wasn't possible before.  Custom is better.