Non-Reflecting Costa Del Mar C-Mates Seven Mile Bifocals Sunglasses

DebiK · #1 (**permalink**) 01-07-2009, 05:44 PM

Do Costa Del Mar C-Mates Seven Mile Bifocals sunglasses have a coating to reduce or eliminate back-glare? That's the light that hits the back of the lenses and bounces into the eyes. The purpose of an anti-reflective (AR) coating is to reduce these reflections off the lenses.
Similar to a scratch-resistant coating, AR is made of a very hard, thin film that is layered on the lens. It is made of material that has an index of refraction that is somewhere between air and glass. This causes the intensity of the light reflected from the inner surface and the light reflected from the outer surface of the film to be nearly equal. When applied in a thickness of about a quarter of light's wavelength, the two reflections from each side of the film basically cancel each other out through destructive interference, minimizing the glare you see.

Juicer · #2 (**permalink**) 01-14-2010, 04:05 PM

Quote:

Originally Posted by DebiK

Do Costa Del Mar C-Mates Seven Mile Bifocals sunglasses have a coating to reduce or eliminate back-glare? That's the light that hits the back of the lenses and bounces into the eyes. The purpose of an anti-reflective (AR) coating is to reduce these reflections off the lenses.
Similar to a scratch-resistant coating, AR is made of a very hard, thin film that is layered on the lens. It is made of material that has an index of refraction that is somewhere between air and glass. This causes the intensity of the light reflected from the inner surface and the light reflected from the outer surface of the film to be nearly equal. When applied in a thickness of about a quarter of light's wavelength, the two reflections from each side of the film basically cancel each other out through destructive interference, minimizing the glare you see.

Here's the "blurb" from the Costa Del Mar website:

Each pair of Costa Del Mar Sunglasses features 100% protection from UV A, B, and C rays, 100% polarization, water-repellent coating, and anti-reflective coating. Mirrored lenses are made of top-quality optical glass. Manufacturer’s lifetime warranty.

So there you have it. Yes, they do have an anti-reflective coating, as do all Costa Del Mar sunglasses, apparently.

DebiK · #3 (**permalink**) 01-29-2010, 03:19 PM

Quote:

Originally Posted by Juicer

Here's the "blurb" from the Costa Del Mar website:

Each pair of Costa Del Mar sunglasses features 100% protection from UV A, B, and C rays, 100% polarization, water-repellent coating, and anti-reflective coating. Mirrored lenses are made of top-quality optical glass. Manufacturer’s lifetime warranty.

So there you have it. Yes, they do have an anti-reflective coating, as do all Costa Del Mar sunglasses, apparently.

Thanks Juicer. So what do you think of my post with all that "destructive interference" stuff?