What is up with this, and how is it being done?
Also, who all makes a clear HEV filtering lens? Essilor and Vision Ease are on my radar. Any others? Anyone using the products? Anything to say about them?
Thanks in advance, and hope you all are having a great day!
Any lens that blocks or reflects significant HEV (blue light) will appear yellow, the more the yellower.
That was my thought. So are these lenses not yellow, or are they not doing what they say?Originally Posted by Dr. Bill Stacy
I'm definitely interested in this tech. I don't mind the yellowing from the blue blocker coatings I've tried but am not really sure how it translates to a clear (non AR) lens.I never did try the BluTech. I read somewhere else on here, someone saying that Transitions have blue blocking tech in them and that manufacturers can use that and make them inactive, but that wouldn't cause a yellowing. You would just have the hint of grey or brown from the Trans... Experience will reveal all!
-kk
Try TheraBlue lenses from Luzerne. They are by far the clearest HEV-blocking technology available. If you aren't holding it up to a white piece of paper, you will be unable to tell that there is any tint in the lens at all.
I'm Andrew Hamm and I approve this message.
Is it 1.56 or 1.67 UV420 with an UV specific AR stack?
Not true Dr. Bill. As AngeHamm mentioned, TheraBlue, and I believe a couple other distributors using the same Matsui (not sure of the spelling) Resin, virtually clear. This has been discussed on numerous threads on here. It does not have the heavy yellow/amberish tint to it. Pretty impressive material. Not a coating as you have so often railed against.
Maybe I wasn't CLEAR enough. The more visible blue any lens removes whether by reflection, by absorption, or both, the more yellow the lens will look. It's simple physics. Lenses that are "virtually" clear, absorb or reflect a significantly smaller amount of blue than the more yellow looking lenses, so one could say they are therefore less "protective".
For people with relatively mild exposure to blue, I use "virtually clear" lenses all the time; for those with heavy blue exposure, I use the heavier yellow lenses.
And I always recommend to everyone that turning down the blue intensity is a good idea (e.g. using www.f.lux on computers, Night Shift on i-phones, and the arizona desert theme on optiboard).
Dr. Stacy, if you haven't seen and handled TheraBlue personally, you need to go out of your way to do so before passing judgement on its appearance. Those of us describing it as virtually clear are not prone to exaggeration. And the physics of frequencies outside the visible spectrum may be relatively simple, but they are more complex than "less blue equals more yellow."
I'm Andrew Hamm and I approve this message.
Quantum physics.
The resin monomer is modified.
Not clear like crown glass, but much clearer than HEV vacuum coatings.
http://www.visionmonday.com/technolo...elength-light/
http://www.businesswire.com/multimed.../#.VfmtGbRH1LA
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
Where did I pass a judgement on TheraBlue appearance? I've seen them up close and personal. They have very little yellow and do indeed qualify as "virtually" clear. My judgement was that if they have very little yellow, they absorb very little blue. And this IS very simple physics, not quantum mechanics. The three primary colors for light are red, green and blue. It takes all 3 in roughly equal amounts to make white light. Take out some blue (by absorption or by reflection, or both, it really doesn't matter), and the resulting light will have more red and green light in it. What does red and green make? Yellow. Not rocket science. If they don't have much yellow, they are NOT taking out much blue. Elementary high school physics. If there is a spectrometer graph available for TheraBlue, it will show only mild absorption of the blue wavelengths.
they are virtually clear, but dr. stacy is correct as well. they are clear because they block a very narrow band of "HEV". usually they are shown with a laser with a wavelength of specifically 405nm it does block this fully but doesn't block much beyond that. that is why they are clear but also are factually blocking less HEV than a lens that appears yellow. the debate of where the line is, in terms of how much blue light is bad is for someone else to debate, that said i think what is often lacking in this discussion is related to the intensity of the light. it isn't just about the wavelength it is also the amplitude that matters.
Short of proper Spectrophotometry, the chart provided by the manufacturer (http://www.businesswire.com/multimed.../#.VfmtGbRH1LA) shows a fairly sharp cutoff starting at 450nm, with a transmission of about 90% at 450nm, more than 80% at 440nm, about 17% at 420nm, and 0% at 415nm.
I've read that the hue is more blue-grey than yellow.
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
They have almost the exact same cut off as a Schott GG420 long pass filter, which reflects a lot more yellow(but does not absorb), therefore appears more yellow.
This is material science vs. thin film coating.
Two totally different technologies to achieve the same result.
Think about it this way, material based/absorptive 0.3 ND filter vs. 50% beam splitter.
Both block transmission by 50% at normal angles of incident, one is grey, the other is white/clear.
Last edited by ml43; 05-16-2016 at 05:02 AM.
The schott lens is a yellow colored glass lens, so it looks yellow from both sides and imparts a strong yellow color to everything viewed through it. It apparently DOES ABSORB wavelenghths 420nm and below, meaning it's an indigo/deep blue/violet and UV absorber which is why it is so yellow. It does NOT have an AR or mirror coating at all, so it reflects pretty much all wavelengths equally. It really looks yellow because that's what is passing through to illuminate whatever is behind it with strongly yellow light.
As for the nd/BS comparison, they are both neutral grey in color, neither is white/clear.
my mistake on the GG420, I normally order it as such, normally coated on one side.
As for the ND filter and beam splitter comparison.
Please find me a 50% beam splitter that appears as grey as a 50% ND filter.
I have a link to one of the patents used for the chemical process that can a achieve a polymer filter that
achieves the same result as a 420 long pass filter, without imparting a strong yellow color.
I'll post it later so everyone can stop debating this.
Last edited by ml43; 05-16-2016 at 09:05 AM.
Do that.The only way a heavy blue absorber will not look yellow is if the light source does not contain yellow wavelengths or is low in either red and green wavelengths or both.
Your beam splitter will look very much like the ND filter when viewed at the angle it is normally oriented when ordinary white light is used. I think it will look less dark when viewed at an angle greater than 45 deg, darker when viewed at an angle less than 45 deg.
We're all gonna die!
ml43,
Chris and I posted a few patent links in the below thread. Were we on the right track?
http://www.optiboard.com/forums/show...l=1#post521614
The only pictures I can find...(previous pictures posted on optiboard were deleted by the OP).
https://www.2020mag.com/ce/Mitsui/Bl...20Solution.PDF
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
Yes, on the right track.
There are many ways to achieve this chemically.
http://www.google.com/patents/US6770692
This isn't the patent I was referencing, I think it's on my other computer.
However, it will suffice for now:
"The present invention provides a plastic base material characterized by that it contains a benzotriazole based ultraviolet absorbent expressed by the general formula (1) and an anthraquinone based violet colorant expressed by the general formula (2), and that it yields a transmittance of 1% or lower for a radiation of 390 nm in wavelength and a transmittance of 10% or lower for a radiation of 400 nm in wavelength. Furthermore, glaring can be efficiently suppressed by reducing the transmittance of radiation of 410 nm in wavelength to a range of from 40 to 60%. If the transmittance at a wavelength of 410 nm should be lowered too excessively, the transmittance in the wavelength region of from 440 to 450 nm may be also influenced to impair the color sensation. On the other hand, if the transmittance above should be set too high, glaring cannot be effectively prevented from occurring."
The patent I found gave the exact chemical concentration by weight with spectographs(both transmission and reflection), to prove that at a certain concentration range, you can achieve a 50% 420nm cut off, while maintaining a relatively flat/broadband reflection, therefore a relatively clear lens compared to standard 420nm filters.
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