Windscreen mystery pattern

[quee2646]

Hello all!

Anyone have any idea what this pattern on the windscreen might be? It is not a heated windscreen. It's only visible first thing in the morning at lower temperatures.

https://drive.google.com/file/d/0B8t7pZ ... sp=sharing

[RobThomas]

Adhesive pattern from when the window was laminated?

[oliver90owner]

If not laminated, likely due to stress pattern from heat treatment (maybe for zone hardening?) altering the reflective/refractive/diffractive properties of the glass across the screen.

RAB

[amgrave]

This is the pattern left by the toughening process, I haven't seen this for a few years but was common before laminated became the norm.

[ManyMinors]

I seem to remember it was called a "Zebra tone" toughened windscreen because of that pattern?

[amgrave]

I think your right there Manyminors. It was so that when the screen shattered into tiny little bits the middle areas were left with bigger fragments you could see through rather than have to punch a hole out to see where you were going.

[Monty-4]

I have exactly the same pattern on my 4-door's windscreen - always wondered what it was!

[Biggles1957]

It's the pattern from the heat treatment to toughen the glass. Polarising lenses show it up nicely!