Also known as peril-sensitive sunglasses. I used to have a pair.
A couple of things…
Boaters and fisherman use polarized glasses for glare, yes, but more so because it allows you to see into the water. Not like a window, but enough to see structure and oftentimes fish.
Also, somebody mentioned having other sunglasses to drive in fog. You should try them during intense rain or fog. Even if I’m driving at night in the fog they help out. It’s pretty cool.
Question…
Is it possible to have polarized glasses that are not sunglasses? That seems like a dumb question, because they function by eliminating half of the light. I suppose it would follow that they would need to be at least somewhat dark to block the light, however, tinted windows do not look dark from the inside.
Yes the polarized lens on most LCDs is clear. See here for an example of a mostly clear polarized lens. It looks shaded until it’s on top of the module. Click on the July 8th 005 post.
But does any company make clear lense, polarized shooting/safety glasses?
I have gauges in my plane that use LCD’s and they cannot be read with polarized lenses.
While I like polarized lenses for general use I find it more important to have lenses that wrap around and prevent light from reflecting off my face back into the lens. A high quality lens will correct for color and back glare.
With some pairs of polarized sunnies i own i’ve noticed that looking out my car windows i can see some rainbow lines moving around on the tint.
Well, the simplest answer is because they don’t sell as well as non-polarized ones. If they sold as well or better, then more or most of them would be polarized. So we move on to why don’t polarized sunglasses sell better. Already some good specific answers to that.
Here’s mine: I thought it was a scam. I didn’t realize what a difference a polarized lens made until I lost my sunglasses and borrowed a polarized pair. Wow! Now I only buy polarized. I’m one of those people who can not hold on to a pair of sunglasses, so I refuse to spend more than $15 on a single pair. Target it is. And the polarized do tend to be on the more expensive rack ($15-20 vs. $10-12), but not so prohibitively expensive that I can’t manage it.
There are polarizing elements that aren’t themselves dark, such as a Glan-Taylor prism, or some kinds of multilayer coated optics, or stacks of parallel glass plates oriented at Brewster’s angle. They DO eliminate half the light, but they aren’t themselves dark. Land’s first polarizing sheets WERE dark, because of the materials used in their construction (iodine in polyvinyl alcohol that got stretched). Later formulations were different, but still dark. Since polarizers were often used in sunvisor-like applications, or with plenty of light, this wasn’t seen as a drawback. The Polaroid sheets could be made larger and more cheaply (and were more compact) than the other polarizers, so it was a tradeoff most people could live with.
You could get or make yourself non-dark polarizing glasses, but they’ll be either unwieldy, or else they’ll cost ya. My suggestiopn would be to get multilayer stack polarizers from Edmund or Corion or Newport or somebody and put them in a glasses frame. They’ll be pricey but not bulky.
If you’re patient, research is ongoing in variable transmission polarized lenses that I believe would be the sort of thing you’re looking for. They would only be “sunglasses” when you’re in the sun.
So, at the risk of hijacking this thread, let me ask another question since it seems that we have some expertise floating around.
There’s somewhat of an argument in the fly fishing community about the quality of the polarization of these glasses. Is polarized polarized? Or are some of them do a better job of polarizing? I’m not talking about the glasses or materials or workmanship, just the polarization.
I’ve worn cheapie $20 jobs on the stream and cannot tell much difference between them and my current $350 pair of Smith Optics. My current ones are, of course, of much better lens and frame quality. The polarization, though, seems to be equal to my untrained eye.
Theoretically speaking, polarization is not an either/or trait. An ideal polarizer would transmit 100% of vertically polarized light and 0% of horizontally polarized light (or vice versa). A cheap plastic polarizer may transmit 80% of vertically polarized light and 2% of horizontally polarized light.
The difference can be obvious if you take two polarizers and hold one in front of the other at a 90-degree angle. If they are both high-quality polarizers, the pair would be totally opaque. If not, the pair would be dark but you’d still be able to see through them.
That said, I have no idea how much actual variation in polarization there is between cheap vs. expensive sunglasses. I rather suspect the difference is small - certainly not enough to notice without the above test.
welding googles?
It certainly IS possible to make a poor polarizer. If you place a sheet of glass at Brewster’s angle, the reflected light will be linearly polarized, but the transmitted light will contain both polarizations – but it’ll have more of the polarization opposite in sense to the light that was reflected than of the light in the same sense. If you now pass that light through another glass plate the reflected light will be linearly polarized, and now the transmitted beam, although still mixed, will have a larger proportion of the opposite polarization. You can keep doing this, and with enough plates you can get the transmitted beam as “pure” as you want. This is a “pile of plates” polarizer, and it’s a good solution for some situations, although it’s a nifty way to demonstrate partially polarized light.
The truth is, it’s very easy to make very good quality polarizers pretty cheap. You can get sheets of polarizing film that pass 99% polarized light and measure 17" X 19" for only $45 from edmund:
http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=2102
“Glacier goggles” also can be very dark.