Checking lens with polarizers

[krugtech]

If anyone uses polarizing filters to check their lens, here's an easier way to do it. Normally you would lay a polarizer on a diffuse light source, lay a lens on top of it and place another polarizer on top of the lens. Rotate one of the polarizers until all the stress in the lens appears.

easier way- open notepad on a computer with an LCD screen. The white LCD screen is an excellent polarized diffuse light source and you probably have an LCD screen on the laser anyway. Then get one ploarizing filter or even a pair of polarized sunglasses and hold the lens between the light source and polarizer filter. Rotate the polarizer and if there's any stress in the lens you'll see it clear as day.

My customers will try this and not see anything, maybe they'll see some clovers where the lens clamp ring was pressing on the lens. Then they'll find a lens that looks fine but the polarizer shows all hell breaking loose inside. As you rotate the polarizer the amount of light coming through should change, if it doesn't then you don't have an LCD screen or the polarizer isn't a polarizer.


Chris Krug

http://krugtech.com/

Maximum Up-time, Minimum BS

 

[MacGyverS2000]

If your clients can't determine whether or not they are using an LCD screen, there are bigger issues to deal with ;-)

Dan - Owner

http://www.Hi-TecDesigns.com

 

[krugtech]

The only reason I mentioned the LCD is some newer displays don't work. The display in my cell phone doesn't work but other cell phones will work. I think some of the new screens are OLED or something that doesn't use polarized light like an LCD does.

Chris Krug

http://krugtech.com/

Maximum Up-time, Minimum BS

 

[IRstuff]

I think they use circular polarization

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