Polarization - New vs Old Oakley Lenses

[Llohr]

I tried to find a thread to discuss this, but left my necromantic kit bag at home this week.

I recently pulled out the polarized lenses that came with a pair of customized Juliets some years back. On a whim,I turned them so the axes of polarization were perpendicular to each other and held them up to a light. The result was an amorphous pattern of near complete blackout.

Repeating the process with a new pair, also BIP, resulted in blackout of the entire overlapping section.

So, have they changed the process in the last eight years or so? I recall that molding the filter into the lens resulted in less complete polarizing (poly fills in some of the grooves), and that info came straight from Oakley, so I guess they found a way around that?

 

[kronin323]

IDK. My polars from seven years ago work as well as recent ones.

The only change to Oakley polar lenses that I'm aware of is it used to be the base tint was in / all the way through the actual polycarbonate for both polar and non-polar. But now they only do that for non-polar; modern polar lenses have clear poly with the base tint as a layer. You can tell by looking at them edge-on.

 

[Llohr]

I hadn't noticed that, but it's very interesting. That suggests, to me, that perhaps they're molding one layer of the lenses (the outside), then adding the polarizing filter, then molding the works to the other layer. That would enable them to add the filter without introducing its grooved face to molten poly, thus preserving the polarization. That would necessitate either adhesive, which they have stated that they don't use, or an ever-so-slightly smaller polarizing filter in order to have contact between the two layers of plutonite. Such a process would produce a better result, I think, but could be more difficult to achieve.

Edit: scratch that hypothesis, it would require that they mold individual lenses one at a time, or that they infix a lot of separate lens-specific filters to the first layer and then cut around each one after adding the second layer.

Though I guess molding plutonite to both sides of a polarizing filter without variations in layer thickness wouldn't exactly be easy.

I'm obviously just making this stuff up as I go along, but that hypothesis would explain the data I've got at hand.

 

[kronin323]

I would expect it's a cost saving measure.

Obviously it's more complicated and expensive to bond the polarizing layer. So it's more efficient to product a single stock of polarized blanks that can be used for all lenses of that curvature. Which implies the order is polarization, base tint, then iridium.