Jim- My limited skills keep me from finding any past threads explaining the difference in these processes so I apologize if you have addressed this before. My colleague and I are having a friendly disagreement on the distinctions between transbonded, imbeded, and imbibed. Could you pontificate?
Also is the reaction on transitions affected by the suns direction (direct vs. from behind).
Since Jim Schafer hasn't pontificated (yet), I would like to share what I have read on line.
There are different processes for fixing the light-sensitive or photochromic dye molecules within an ophthalmic lens.
Corning Sunsensors and Rodenstock ColorMatic use an "In Mass" method. The dye molecules are evenly distributed throughout the entire lens substrate, from the front surface all the way through to the backside. The dye molecules in the middle and backside of the lens are not exposed to as much of the activating UV light as the dye molecules at or near the front surface.
There are other methods that confine the dye molecules to a thin layer or band that is close to or at the very front surface of the lens.
The next post down (from Jim Schafer) describes the two processes that are used for the Transitions photochromic package, depending on the lens substrate. One process is known as "Imbibed"; the other is called "Trans-Bonding".
SignetArmorlite's Kodak InstaShades lenses are somewhat alike to Transitions in that the dye molecules are fixed to a depth of 0.8 mm from the front surface of the lens. They use what they call their "Multi-Matrix" technology, which involves some kind of chemical bonding between the dye molecules and the lens substrate.
The Life-Rx polycarbonate lenses from Vison-Ease use another method that fixes the dye molecules near the front surface of the lens:About that second question, it seems to me that the only way that there would be a difference is during low sun angles early or late in the day. Then if you were looking the other way (from the sun), you'd have mostly backlighting. And I think it is safe to say that under such conditions, regardless of whatever direction you were looking, there would not be as much darkening of a Transitions or any other kind of photochromic lens as there would be under the midday sun. Once again, however, there is more about this from Jim Schafer; see the next post after this one.Imbedded Film technology is the newest and is used by Vision-Ease Lens to uniquely create polycarbonate flat top and other [styles of] photochromic lenses. The front of the lens is a polycarbonate covered photochromic film. The balance of the lens blank (the thick portion) is polycarbonate and forms the semi-finished blank used by the laboratory to create any variety of prescriptions. UV, which activates the photochromic dye in the film, passes through the front of the lens and darkens the film. Because the film is uniform throughout the front of the lens, the color and density or darkness is also uniform.
Sources:
20/20 Magazine on line
Corning Ophthalmic
http://www.signetarmorlite.com/lab/TIPS247.htm
Last edited by rinselberg; 02-06-2008 at 07:05 AM. Reason: Additional information from Jim Schafer
Hi Uncle Fester..and Rinsie,
Imbibed is a Transitions lens process for standard index, mid index (Spectralite Velocity and X-Cel High X 1.55) Trivex segmented lenses.
This is a heat driven process where the photochromic package becomes part of the lens surface, driven 200 microns into the front surface if the lens.
Trans-Bonding is another Transitions lens process for polycarbonate, Trivex, 1.6 High Index and 1.67 Ultra High Index. An Ophthalmic Grade Photochromic film is bonded to the front surface of the lens.
What is so great about Transitions VI technology is that for the first time, both imbibed and Trans-bonded lenses are at the same performance level.
On the question about full sun activation, all photochromic lenses are darker and faster reacting in full sun. However, what you and your colleague were discussing is the directionality, fast acting dyes that need full sun to achieve full activation.
Transitions V were directional, more sun face, the darker, move out of direct sun and they would begin to fade. This is not the case with Transitions VI, we slowed down the directionality.
I hope this helps,
regards,
Jim
Last edited by Jim Schafer; 08-18-2008 at 12:59 PM. Reason: more correct of a statement
Jim Schafer
Retired From PPG Industries/
Transitions Optical, Inc.
When you win, say nothing. When you lose, say even less.
Paul Brown
No one has mentioned this but the surface bonded and imbibed products darken evenly. The others darken more in the thicker areas of the lenses.
Chip
Chip check out laramy-k's website on the photchromic section of the ABO Openoptix study guide it is mentioned.Originally Posted by chip anderson
1st* HTML5 Tracer Software
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*Dave at OptiVision has a web based tracer integration package that's awesome.
Yes, the Bulls Eye on plus lenses and Racooning on minus lenses.No one has mentioned this but the surface bonded and imbibed products darken evenly. The others darken more in the thicker areas of the lenses.
Chip
have a great day,
Jim
Jim Schafer
Retired From PPG Industries/
Transitions Optical, Inc.
When you win, say nothing. When you lose, say even less.
Paul Brown
Thanks to all! This one's on me.:cheers:
Gee, if you ground 8D prism, would you have gradient lenses?:D
Shudders at remembering Photogrey Gradients.
DragonlensmanWV N.A.O.L.
"There is nothing patriotic about hating your government or pretending you can hate your government but love your country."
Transitions the same in poly vs. trivex?
I have an email from the Technical director for one of the big lens companies and he claims " The transitions is better on poly than trivex."
I thought it was the same at this point between all materials. Trivex does allow more light to pass without AR, but not enough to notice. With an AR, it should be the same?
Please let me know; I am working to get rid of poly and replace it with trivex products.
Thanks
Craig
Hi Craig,
I hope all is well.
That is a false statement by that director. All Transitions VI lens materials, regardless of manufacturer, have the same performance parameters (activation speed, darkness and fadeback speed). Trivex Transitions VI availability is in the Single Vision and all Progressives.I have an email from the Technical director for one of the big lens companies and he claims " The transitions is better on poly than trivex."
The imbibed segmented bifocal and trifocal Trivex, is a hybrid of Next Generation and Transitions V. It is darker than Transitions V and faster than Next Generation. Because it was released about 18 months before the Transitions VI launch and is close to Transitions VI in performance, it was felt there was no need to upgrade at this time.
If you get a chance, please email me with more information. (by that I mean, is this an official document or his opinion)
have a great day,
Jim
Jim Schafer
Retired From PPG Industries/
Transitions Optical, Inc.
When you win, say nothing. When you lose, say even less.
Paul Brown
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