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#321733 - 26/04/2009 18:57 Polarization interference sunglasses
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
Are there any opticians here?

My wife has very sensitive eyes, and has a hard time getting sunglasses that are dark enough. Opticians always claim that "that's as dark as we can get them", the process clearly being dyeing.

Wouldn't it be possible to grind two polarized lenses and glue them together at a particular angle? It seems to me that you could pretty easily select 50% to nearly 100% with that method. I recognize that it would obviously be harder to accomplish than with dyeing, but it would solve her problem.

Anyone have any feedback?
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Bitt Faulk

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#321734 - 26/04/2009 19:07 Re: Polarization interference sunglasses [Re: wfaulk]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14493
Loc: Canada
Sounds reasonable.

Cheaper might be some simple windscreen tint (self-stick) plastic, cut and stuck over existing sunglass lenses.

??

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#321737 - 26/04/2009 19:55 Re: Polarization interference sunglasses [Re: mlord]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
Well, I was thinking of a more professional solution, but, yeah, that ought to work too.
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Bitt Faulk

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#321738 - 26/04/2009 20:46 Re: Polarization interference sunglasses [Re: wfaulk]
gbeer
carpal tunnel

Registered: 17/12/2000
Posts: 2665
Loc: Manteca, California
Metalization (gold via vapor deposition) can give you any grade you desire, right down to stare at the sun darkening.
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Glenn

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#321739 - 26/04/2009 22:33 Re: Polarization interference sunglasses [Re: wfaulk]
lectric
pooh-bah

Registered: 20/01/2002
Posts: 2085
Loc: New Orleans, LA
Souds like she needs a set of these from 1940!

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#321740 - 26/04/2009 22:36 Re: Polarization interference sunglasses [Re: gbeer]
Robotic
pooh-bah

Registered: 06/04/2005
Posts: 2026
Loc: Seattle transplant

lol

Or- maybe find one of those tinted face shields that the asian women wear and put on a pair of sunglasses under that.
I'll be danged if I can conjure a GIS image for that face shield, though. Weak fu today.

edit:
Ah- here's some info and pics.


Edited by Robotic (26/04/2009 22:45)
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10101311 (20GB- backup empeg)
10101466 (2x60GB, Eutronix/GreenLights Blue) (Stolen!)

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#321741 - 26/04/2009 23:32 Re: Polarization interference sunglasses [Re: Robotic]
hybrid8
carpal tunnel

Registered: 12/11/2001
Posts: 7738
Loc: Toronto, CANADA


Damn, I pulled the image up so fast (not because it's my desktop image), that I didn't notice the link at the end of the previous post...


Edited by hybrid8 (26/04/2009 23:33)
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Bruno
Twisted Melon : Fine Mac OS Software

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#321742 - 26/04/2009 23:46 Re: Polarization interference sunglasses [Re: wfaulk]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31597
Loc: Seattle, WA
Quote:
Wouldn't it be possible to grind two polarized lenses and glue them together at a particular angle?


You'd get a moire pattern.
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Tony Fabris

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#321743 - 26/04/2009 23:49 Re: Polarization interference sunglasses [Re: tfabris]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
I've personally looked through two polarized planes and there is no moire.

In fact, so have you, because that's how LCDs work.
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Bitt Faulk

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#321744 - 27/04/2009 01:52 Re: Polarization interference sunglasses [Re: tfabris]
lectric
pooh-bah

Registered: 20/01/2002
Posts: 2085
Loc: New Orleans, LA
Originally Posted By: tfabris
Quote:
Wouldn't it be possible to grind two polarized lenses and glue them together at a particular angle?


You'd get a moire pattern.


You would only get that in cars, and only because of the way the windshields are polarized. I think It's a cool looking effect, actually. I saw a while back some electronic blinds that used LCD tech to turn darker. One plate was polarized at 90 and the lcd was polarized at 180. By applying a weak electrical current to the LCD, the entire window just got darker. It even included a remote control.

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#321745 - 27/04/2009 03:43 Re: Polarization interference sunglasses [Re: wfaulk]
Roger
carpal tunnel

Registered: 18/01/2000
Posts: 5683
Loc: London, UK
Originally Posted By: wfaulk
Opticians always claim that "that's as dark as we can get them"


Bull. I've got a sextant with filters on it that allows you to look directly at the sun.

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-- roger

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#321758 - 27/04/2009 10:45 Re: Polarization interference sunglasses [Re: Roger]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
Clearly, as she's had glasses darker than that before. But there's got to be some technique that they use exclusively these days. It's not a problem unique to one optician. Maybe it has to do with plastic versus glass.
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Bitt Faulk

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#321771 - 27/04/2009 19:10 Re: Polarization interference sunglasses [Re: wfaulk]
canuckInOR
carpal tunnel

Registered: 13/02/2002
Posts: 3212
Loc: Portland, OR
Originally Posted By: wfaulk
My wife has very sensitive eyes, and has a hard time getting sunglasses that are dark enough.

Is she looking for prescription sunglasses, or just regular sunglasses? If the latter, perhaps she could try mountaineering sunglasses, which are (sometimes) significantly darker than the regular variety.

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#321773 - 27/04/2009 19:19 Re: Polarization interference sunglasses [Re: canuckInOR]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
Prescription. But it's still a good point that they might make prescription mountaineering sunglasses.
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Bitt Faulk

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#321788 - 27/04/2009 23:27 Re: Polarization interference sunglasses [Re: Roger]
gbeer
carpal tunnel

Registered: 17/12/2000
Posts: 2665
Loc: Manteca, California
Originally Posted By: Roger
Originally Posted By: wfaulk
Opticians always claim that "that's as dark as we can get them"


Bull. I've got a sextant with filters on it that allows you to look directly at the sun.



I suspect the problem is that today a lot of eyeglasses are made using prefabricated lenses. Tints are standardized and stocked in a warehouse. Blame the inexpensive 1 hr Eyeglass shops for that revolution.

From past experience, I do know that opticians are wary about supplying extra dark tints. You may have to wave any satisfaction guarantee.

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Glenn

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#322214 - 12/05/2009 16:59 Re: Polarization interference sunglasses [Re: wfaulk]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31597
Loc: Seattle, WA
Either Fishy needs to hang out on this BBS more, or you guys need to be on LiveJournal and friend him:

http://gfish.livejournal.com/278884.html
_________________________
Tony Fabris

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#322219 - 12/05/2009 21:46 Re: Polarization interference sunglasses [Re: gbeer]
tman
carpal tunnel

Registered: 24/12/2001
Posts: 5528
Originally Posted By: gbeer
I suspect the problem is that today a lot of eyeglasses are made using prefabricated lenses. Tints are standardized and stocked in a warehouse. Blame the inexpensive 1 hr Eyeglass shops for that revolution.

If you ask somebody at a smaller independent opticians then they might be able to help. I have to get my lenses specially ordered because I'm about -2 in both eyes but have a high astigmatism. If I just got regular lenses then they'd be pretty thick.

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