SPIE Fellow Peter Hartmann, who is also director of market and customer relations for Schott (Mainz, Germany), has recently pointed out a drawback of the European Union's REACH and RoHS regulations, at least to the European photonics industry: the potential demise of virtually all good optical flint glasses (the high-index glasses that, when combined with low-index glass in a proper optical design, result in color correction; used in everything from achromatic doublets to microscope objectives, camera lenses of all types, and just about any other high-end nonmonochromatic visible optical system). Hartmann writes about this in the SPIE Professional's April issue.
The EU's REACH (Registration, Evaluation, Authorization, and Restriction of Chemical) and RoHS (Restriction of Hazardous Substances) regulations are designed to phase out toxic substances used in European industry; these will include some substances used in the manufacture of virtually all flint (and many crown) glasses—including lead, a fundamental component of flint glass. Other photonic-related materials on the list include arsenic oxide and cadmium.
Without going into the detail Hartmann does (I suggest you read his article), I'll note that the uses of these materials will be restricted or prohibited, some earlier than others, with arsenic oxide being banned on 21 May 2015.
Prepare to run
Hartmann says, "Lead oxide is present in up to 75% of classical flint glasses. It can be removed completely. However, even with long and intensive research, no compositions have been found that have the same high transmission in blue-violet light as the lead glasses. Using only lead-free glass in microscopes thus cuts away an important part of the spectrum. Rigid endoscopes have a glass light path of 400 mm, sometimes even 600 mm. Images from the abdominal cavity from these lead-free instruments will be dark, with hardly any color contrast."
He adds, "If you are to be exposed to minimally invasive surgery, ask the doctor if s/he uses lead-free glass in his/her endoscope. And if s/he does, stand up and run!"
Hartmann notes that "the problems with RoHS and REACH were presented to the Science and Technology Options Assessment (STOA) committee at the European Parliament in February. To the author’s impression, it was the first time that the message was received by EU officials, with feedback that they have understood and are also concerned about the situation. But the situation is not yet resolved."
Given that the European Union is dead-serious about boosting the European photonics industry, I suspect common sense will prevail here. Still, the sooner that these hitches are worked out, the less likely that some design and fabrication operation somewhere will have to be halted or retooled while risks and benefits are being discussed.
