Awesome! Thank you for the update, Varilux.

Deysha

 

Unaided awareness = dude, what's up with your windshield?
In market research, "unaided awareness" means the consumer can name your product (or its attributes) with no prompting. It means you have a really strong brand. Coke is considered to be the strongest brand in the world, because it has the highest unaided awareness of any brand in any category on a worldwide scale (ask anyone from almost anywhere to name a carbonated beverage, and Coke is in the top 3- in fact, ask a consumer to name ANY brand and Coke usually is near the top of the list).

Anyway, when I have a new passenger in the car, I do not mention the windshield (thus avoiding "biasing"). Sure enough, most of them will eventually mention the "funky windshield." I'll have to try and snap a picture, but it looks like a plowed field- little ripples running vertically (almost causes portions of the image to look like it has blotchy shadows, and straight lines will waver when the car is in motion).

I received a call today from my service tech- Ford has agreed to replace the window, and someone from their glass vendor will contact me to arrange installation. I'm really glad they are taking care of this- I would have seriously considered replacing it on my own dime if they said the waves weren't serious enough to warrant replacement (but now I can put that money towards the FRPP Procal Package )!

 

Thanks for the explanation...sorry that I left a smiley off of my response.

It is great that Ford is doing you right with this one. I hope the issue is uncommon.

Here is an optics question regarding the windshield flaws. Are the ripples more or less visible if you're wearing polarized sunglasses? I wear them often and flaws in all types of glass stand out horribly with them on. You can see stress points where glass has been tempered unevenly and other irregularities easily through polarized light.

 

Here is an optics question regarding the windshield flaws. Are the ripples more or less visible if you're wearing polarized sunglasses?
Warning- I direct technical marketing for Essilor Intl (world's largest manufacturer of ophthalmic lenses)- so I totally geek out over questions like this!

Actually, if you see "dots" or "patterns" in a windshield when wearing polarized sunlenses, you are not seeing distortion. You are seeing internal stress (usually caused by tempering- but sometimes caused by the mounting of the glass). If you see rows of "dots" on the glass (usually seen on rear windows- which do not usually have the laminate) you are seeing heat tempering patterns. If you see purple all over the rear window (usually seen on Mercedes, etc.), you are usually seeing a chemical tempering process.

Glass has internal stress because it is a thermoplastic (that is, it starts in a solid form- silica, et al, and can be remelted). Most eyeglass lens materials are thermalcure, btw (they start life as a liquid and will never melt again once set into shape... try it, your lens will burst into flame but it will never melt... unless it is made of polycarbonate which is also a thermalplastic). One property of thermoplastics is they form stress patterns when they are cast into a shape. Tempering is done by raising the temperature almost to melting- then slowly cooling the glass to "organize" the internal stress.

Unfortunately, another property of thermoplastics is birefringence (the molecule has a different index of refraction along one axis than it does along another). This causes the glass to refract light differently from different angles (and this is probably what is causing the distortion in my windshield). Birefringence is a byproduct of tempering- and since polarized lenses only let light through at one axis (which is why they are so good at blocking horizontal glare) they allow you to see the birefringent patterns in the glass. Most FRONT glass will not have these patterns, because the front glass relies on a vinyl sheet that is sandwiched into the glass to hold it together when it is smashed. In my windshield, the heat of the glass was probably not controlled well, with a result that the stress ended up being unorganized, leading to ripples across the surface.

Sorry (I know, I know... no one cares about this stuff)!

 

^ I'm interested in stuff like this. (I have a few pairs of Essilor lenses too.) I can see those patterns (large "dots") in my rear window when wearing polarized sunglasses (Nikon...sorry!). There is no visible distortion in any of my windows though ('13).

 

Varilux- great explanation.

I've worn glasses most of my life. With the new UV-protected car glass these days, I've stopped getting polarized glasses because I see spots or patterns on most windows now. I get the Transitions lenses with anti-glare. Expensive, but worth it for me. /hijack

 

 

As far as the glass is concerned I've only noticed the normal manufacturing type stuff Varilux mentions when conditions are just right when I am outside the car. I've noticed this on my other cars so I know it's normal. But the one thing that is annoying is there's a considerable reflection of the interior on the windshield much more of the time than I am used to. Either it is due to the glass roof letting in more light or there was a design compromise made somewhere. It's certainly not any sort of defect but some kind of trade off made in development. Maybe I'll close the shade next time and see if it goes away.

As to ripples and distortions I haven't noticed anything.

Varilux, don't worry about it, such stuff improves the discussions as far as I am concerned. Years ago I had to deal with lenses over displays on electronics. Had to get the supplier to mold them without the residual stresses or people wearing polarized sunglasses wouldn't be able to read the display. Thus I know what you're talking about but from a plastics/injection molding POV.

 

^ There was quite a lot of talk about the internal reflections on the windshield a while ago. Specifically as to at night and choosing the least annoying MyColor option, but it is a bit noticeable in the daytime too. I wonder if it's some coating on the glass? It is quite hard to block without getting into some weird shield/hood over the gauges. I don't have a glass roof, so that's not the main cause.

I have a 20+ year old Ford too, and it has those stress spots in the rear window, only visible with polarized lenses. I didn't know what it was after all these years until Varilux mentioned it. As for my '13, they're only visible with polarized lenses when I turn around to back up. Most of the time I'm looking out the rear window via the rear-view mirror, so I don't see them then, I have to look directly. I do notice the window over the basic "stereo" display requires tilting my head a bit to read with the sunglasses, but at least it's readable (some aren't).

 

I can't see anything. However I can feel a "dent" in the glass around the rear mirror when I dry off the windshield after washing.