I found what I had been looking for a while, and I am going to share it with anyone that has some interest. Dr. Peter Wilkinson asked me a few years ago for any documentation on my Blue Blocker dye because he had been commisioned by a major optical manufacturer to do some research on it in combination with AR coatings.
So I fell on this paper written by him and it could be interest to many OptiBoard Members. This is purely eductional and non commercial.
Coatings and tintsPart 1: Manufacture and dispensing factors
Dr Peter Wilkinson PhD, BSc (Eng), CEng, MIMechE
This two-part article describes the important aspects of coatings and tints.Part 1 gives some history of how they have developed, how they are nowmanufactured, and the main factors to be considered in dispensing. Part 2will describe recent technological developments, what products are nowavailable, and speculate about the future.
Early history, glass lensesand single-layer AR
Before CR39 came into common use, theavailability of tinted lenses was limited bythe manufacturing process and could onlybe produced in two ways. One method wasto incorporate coloured chemicals into theglass when it was melted (this, of course, ishow photochromic glass lenses are stillmade). The other method was to apply thecolour as a vacuum coating, using the sametechniques and equipment as for AR coating.For both methods, the range of colourswas very limited. One innovative alternative,which never came into common commercialuse, was developed by Corning; a thin layerof plastic was adhered to the rear surface ofglass lenses, which could then be tintedusing the same dyes as for CR39.When a dark tint is applied, it is importantthat UV transmittance is restricted (seelater). For glass lenses, creating UV absorptionis not as easy as for plastics and resinlenses, although historically this factor wasnot considered as important as it is today.Photochromic glass does, of course, provideUV absorption naturally because it functionsmainly by absorbing UV light.As high index glass came into commonuse, vacuum coating techniques were developedto reduce the strong surface reflections.As shown in Table 1, these reflectionscan amount to between 8% for low indexmaterials, to almost 20% for very highindex materials. Calculation of reflection as follows:
see all of it at: ===================>
http://ift.tt/1NIeFt5
Coatings and tints Part 1: Manufacture and dispensing factors
So I fell on this paper written by him and it could be interest to many OptiBoard Members. This is purely eductional and non commercial.
Coatings and tintsPart 1: Manufacture and dispensing factors
Dr Peter Wilkinson PhD, BSc (Eng), CEng, MIMechE
This two-part article describes the important aspects of coatings and tints.Part 1 gives some history of how they have developed, how they are nowmanufactured, and the main factors to be considered in dispensing. Part 2will describe recent technological developments, what products are nowavailable, and speculate about the future.
Early history, glass lensesand single-layer AR
Before CR39 came into common use, theavailability of tinted lenses was limited bythe manufacturing process and could onlybe produced in two ways. One method wasto incorporate coloured chemicals into theglass when it was melted (this, of course, ishow photochromic glass lenses are stillmade). The other method was to apply thecolour as a vacuum coating, using the sametechniques and equipment as for AR coating.For both methods, the range of colourswas very limited. One innovative alternative,which never came into common commercialuse, was developed by Corning; a thin layerof plastic was adhered to the rear surface ofglass lenses, which could then be tintedusing the same dyes as for CR39.When a dark tint is applied, it is importantthat UV transmittance is restricted (seelater). For glass lenses, creating UV absorptionis not as easy as for plastics and resinlenses, although historically this factor wasnot considered as important as it is today.Photochromic glass does, of course, provideUV absorption naturally because it functionsmainly by absorbing UV light.As high index glass came into commonuse, vacuum coating techniques were developedto reduce the strong surface reflections.As shown in Table 1, these reflectionscan amount to between 8% for low indexmaterials, to almost 20% for very highindex materials. Calculation of reflection as follows:
see all of it at: ===================>
http://ift.tt/1NIeFt5
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