Howdy,
I hope I have the right forum for this post.
Can someone please explain how the Nupolar lenses are tinted.
I am under the understanding that a +4.00 will come back
a different density then a +3.00
Thanks
Rick Strong
Howdy,
I hope I have the right forum for this post.
Can someone please explain how the Nupolar lenses are tinted.
I am under the understanding that a +4.00 will come back
a different density then a +3.00
Thanks
Rick Strong
We have been using this lenses for years, no problem with density but very rarely, maybe from old batch, lenses have a slightly different color.
Joseph Felker
AllentownOptical.com
It is my understanding that the polarization is located at the front surface of the lens, so color density remains constant regardless of the power or thickness of the lens. Otherwise you would have a darker center in plus powers and lighter centers in minus. The Nupolar design is similar except new manufacturing methods have eliminated the need for a laminated wafer cemented between the lens front and a cover lens. This is much more attractive and functional. We have seen no problems with this design at our lab, and no color shifts from center to edge. Younger has a keeper!
Shutterbug
In most cases, the lenses themselves are not tinted, at least not as they come from the manufacturer. However the lab may tint the lenses during processing, to make them darker.
The color of a polarized lens comes from the polarizing "filter" within the lens. The filter is made up of a thin, translucent film that is randomly imbedded with iodine crystals. The film is then stretched in one direction, which causes the crystals to align in parallel rows. Dye is used to color the rows of iodine crystals, which results in the filtration and the polarization of light. Basically, the filter functions like a set of micro-mini blinds once cut to shape and cast into the lens.
Again, the filter itself is what gives a polarized lens its color. Some manufacturers hand match pairs of polarized lenses by base and add, to ensure consistency within one pair. If Younger does this (and I am not sure whether they do or not), and the lab has to pull two separate pairs and split them up, there may be a slight difference from one lens to the other.
From what I understand, Younger is known for being particular about the quality and consistency of their colors, so I would think that you should be able to supply this patient a product of reasonable quality regardless.
Here is just a representation of the Nupolar film in a very rudimentary way.
As discussed, the polarization is never a surface treatment, but rather a filter.
CEO:
That was WAY cool -- may I use this graphic in a polarized lens seminar that I am writing for Shamir Insight? Only with your permission, of course.
An age old question,
Has anyone come across a "clear polarized lens", by clear I mean no visable tint/colour? If so, how effective would it be?
The reason I ask, is a number of years ago I had a client wanting a pair like this. He said that they were widely used by Rommell in Africa in WWII.
Have been told by many (and beleive me I've asked) that it can't be done. I do think I have seen such stuff in microscopes though.
Chip
It is my understanding that a polarized filter that offers 99% plus can not be a light colored lens. Susan and Ceo covered that (great graphic, can I use it for a course or two myself?) . There are lighter colored lenses that offer 50% or so polarized effect that are common in club or cafe lenses. I happen to own a pair.
The Younger Nupolar filter is my favorite when dispensing the best sun protection I can offer the patient. It does not delaminate like some of the others.
This is Pete Hanlin's greatest ambition - if i can remember rightly!Corey Nicholls said:
Has anyone come across a "clear polarized lens", by clear I mean no visable tint/colour? If so, how effective would it be?
curiosity killed the cat...well, in that case i should be dead soon
I've brought this up before I think but what about circular polarizers in SLR cameras? How exactly do those work and what is the reason that they have not been used in eyewear?
I am going to step out there -- even though I know nothing of the polarizing filters used in cameras ... could be a mistake ... but, what the heck!
Everything that I have learned about polarizing filters is that if they were clear, they would not filter much of anything, let alone polarized light. Therefore, my guess is that even camera filters are just that, colored polarized filters that are offset by the extremely bright lighting conditions, under which they are used.
Remember ... I admitted up front that I do not know anything about camera filters, but I do know a bit about spectacle lenses. Anyone out there a camera buff (Steve??? -- you took some beautiful photos at my wedding, some of the best I have!). Can you tell us anything more?
Susan,
Actually I don't think anyone has eplained it better than Darryl did here:
http://www.optiboard.com/forums/show...lear#post47382
As for the citcular polarizing filters for cameras, they are still linear as far as I can tell (that's why their effects change when you rotate the filter.) It's just that they are cut into a round shape to match the lens.
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