Polarization Power

[homanhong]

Dear all,

Anyone can suggest a method to test the polarization power? Any method if I want to test how good of the polarized lenses can block the light when two pieces come together with one turned 90deg. Thanks.

Homan

[HarryChiling]

If one is turned 90 degrees you shouldn't have any light coming through. Is that what you are trying to test for?

[homanhong]

Dear Harry,

Yes... But some polarized lenses can't block all light even in 90deg from each other. That is the point I would like to check.

Homan

If one is turned 90 degrees you shouldn't have any light coming through. Is that what you are trying to test for?

[chip anderson]

Harry: Some of the lighter colors (yellow and amber for example) block out much less than darker colors, (I have been told that the darker color has "more polarization effect.) and may not be reduceing glare or brightness as effectively as the darker shades. I don't fully understand why this is so, but it is related to why one cannot have a "clear polarized" lens.

l just went out and tested my NuPolar Canary-Yellow and my NuPolar Yellow samples from my trial set and the amount of reflected glare, general glare and light in general blocked is next to nothing.

This may also give a partial answer to my post a few years ago asking why a sunglass company in Florida was claiming that "Most polarized lenses are only 40~80% polarized and ours are 100% polarized."

Chip

[Darryl Meister]

The standard test measurement from the ANSI Z80.3 Standard (Non-prescription Sunglasses and Fashion Eyewear) is the luminous transmittance ratio (R):

R = Tmax / Tmin

where Tmax is the maximum luminous transmittance of the polarizing lens when measured using a beam of linearly polarized light with the axes of polarization parallel to each other, and Tmax is the minimum luminous transmittance of the lens when measured perpendicular (or "crossed") to a beam of linearly polarized light.

[HarryChiling]

Thanks for posting that Darryl, you wouldn't happen to have a copy of this standard?

[Darryl Meister]

Unfortunately, not in a form that can be redistributed.

[homanhong]

Dear Darryl,

If I am going to use spectrophotometer to test the luminous transmittance ratio, do I need to have one standard polarized lens and put them together in the machine? Thanks.

Homan

The standard test measurement from the ANSI Z80.3 Standard (Non-prescription Sunglasses and Fashion Eyewear) is the luminous transmittance ratio (R):

R = Tmax / Tmin

where Tmax is the maximum luminous transmittance of the polarizing lens when measured using a beam of linearly polarized light with the axes of polarization parallel to each other, and Tmax is the minimum luminous transmittance of the lens when measured perpendicular (or "crossed") to a beam of linearly polarized light.

[Darryl Meister]

You might check with the manufacturer of your spectrophotometer about possible options.

[William Walker]

If you were to have a standard polarized lens with the spectrophotometer to cross your test lens with, how would the standard lens be tested, and how might that alter the test results? I assume there must be a different way.

[AWTECH]

Spectrophotometer

If you would like more information on the polarized lens testing using a spectrophotometer please contact me by e-mail. I will also leave you a private message with my mobile telephone number.

I am not exactly sure what you are looking for but being very knowledgeable on polarized lenses and having a spectrophotometer I maybe able to help.