Laser Cutter vs. Mirrorshades: Front

Well, a shattered lens found beside the road on a walk:

Laser vs sunglasses - focused overview
Laser vs sunglasses – focused overview

The battered frame has enough information to suggest they were once rather fancy. At this point, all that matters is they have two glass layers separated by a dark plastic polarizing film, with a gold-ish metallized front glass surface.

I fired the two pulses (on the left side of the obvious crack) at the front of the lens, both at 100 ms / 70% power:

Laser vs sunglasses - overview
Laser vs sunglasses – overview

Neither pulse penetrated the lens.

The smaller zit was fired in the position shown in the first picture, with the focal point more-or-less at the top surface of the lens. As seen from the front:

Laser vs sunglasses - focused front
Laser vs sunglasses – focused front

The outer part of the damaged area is about 0.5 mm in diameter. The heat around the damage seems to have cleared away all the schmutz on the lens; those things that look like scratches are oily smears and road dirt.

Seen from the rear:

Laser vs sunglasses - focused rear
Laser vs sunglasses – focused rear

The rear surface is blistered, but doesn’t have a hole, so I think the beam melted the glass and inflated a cavity along its path.

I then perched the lens in the unfocused beam path, with paper taped over the laser head opening to keep any fragments off the mirror and focus lens:

Laser vs sunglasses - beam front overview
Laser vs sunglasses – beam front overview

The beam produced the larger scar and also blasted off a ring of crud around the wound, as seen from the front surface:

Laser vs sunglasses - beam front
Laser vs sunglasses – beam front

The beam seems to have shattered a thin layer under the metallization, but didn’t do any deeper damage. The rear surface is undamaged and the paper didn’t have a scorch mark.

They’re not laser safety glasses, but at least they didn’t disintegrate.

Protip: do not lie on the laser platform and stare upward into the laser head, even while wearing fancy polarized mirrorshades.

3 thoughts on “Laser Cutter vs. Mirrorshades: Front

  1. So I shouldn’t use my 80W laser as an emergency tanning bed over Christmas when the regular providers are closed for the holiday period? Next you’ll be recommending against using my lawnmower as emergency finger nail trimmers. Gosh, what’s the world coming to?

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