EU regulations endanger present and future technical civilization
(Details)
Purpose of this documentation is to provide detailed evidence for the statements put forward in the
position paper with the same title “EU regulations endanger present and future technical civilization”,
which had to be kept short.
The covered field optical technology is very wide and complex and extends over many levels of
supplier – customer relations. Most optical systems are used outside optics itself and support all
industry, not only high tech industry. These systems are and will be a necessary precondition for
present day and future products and services to become possible. Highly value added systems can
work with the needed high performance only when the preceding stages in their production also
perform on highest levels. This leads to the known but still underestimated high leverage effect of the
early stages in the supply chain: raw material supply, optical material and optical element production.
Products of later stages with values higher by factors of 100 and even 10000 will not work at all if the
early stages suffer from availability and quality variations.
On the other hand production of optical materials is a very small business. As a rule their share in the
price of an optical system is about 1 percent. For many optical material types required amounts are so
small that continuous production is not possible in an economic way. Moreover the required amount is
highly volatile. A production lot may be sufficient for a full year’s supply in one year and in the other
year it can be sold three times within one month. Because of many technical conditions the production
of additional material is not possible in short terms. So a sold out material can be supplied only many
months or even years later. This fact is observed since the beginning of optical glass production and is
the reason, why a long term continuous availability for optical materials is an issue ever since and why
this will go on also in future but now even more endangered by government regulations.
The complexity of the fields leads to the fact that probably nobody has a complete overview and can
give a comprehensive picture of it. Therefore this documentation must be understood as a collection of
contributions from different levels of optical technology production and application.
It starts with the contribution of the optical glass manufacturer SCHOTT AG to lay the basis for
analyses of contributions from representatives of the higher value-added levels by evaluating the
consequences of EU REACH and RoHS regulations on the optical material portfolio of company
SCHOTT AG.
As a first reference for the consequences on optical systems applications the letter was used, which
was submitted by company Carl Zeiss to the German industry association SPECTARIS
“Verlängerung der RoHS-Ausnahme #13 „Pb und Cd in optischen Gläsern und Filtergläsern“
Verbandsabstimmung vom 25.02.2008”dated March 11th, 2008. This letter formed the details basis for
the application for the prolongation of the RoHS exemption for optical and filter glasses as listed as
points 13 a and b in annex III of RoHS.
Companies involved in collecting the application examples were
•
Schott AG
•
Carl Zeiss AG
•
Dr. Johannes Heidenhain GmbH
•
Schmidt + Haensch GmbH&Co, Berlin
•
Jos. Schneider, Optische Werke GmbH, Kreuznach
•
Leica-Geosystems
•
Berliner Glas / SwissOptic
•
Linos Photonics GmbH
This document is work in progress.
Everybody is invited to contribute to the collection of optical systems and their applications, which are
endangered by the regulations.
Dr. Peter Hartmann Advanced Optics
SCHOTT AG
10.4.2013
[email protected]
EU regulations endanger present and future technical civilization (Details)
as of 11.4.2013
Page 1 of 24
EU regulations endanger present and future technical civilization
(Details)
Two EU regulations (REACH and RoHS) endanger short and long term
availability of optical materials, which are vital for general technology, research
and development for example in medicine, life sciences, computer technology,
safety and security. Prohibition of the materials themselves or their raw materials
or uneconomic administrative effort will lead to the loss of many special materials
impairing the performance of optical systems strongly if not preventing it totally.
Because of the extreme leverage effect of optical systems this would be very
harmful for the goals set out by the EU in their Horizon 2020 program: Excellent
science, Industrial leadership and Societal challenges.
The EU regulation (EC) No. 1907/2006 concerning the Registration, Evaluation and Authorisation and
Restriction of Chemicals (REACH) and the EU directive 2011/65/EU on the Restriction of the use of
certain Hazardous Substances in electrical and electronic equipment (RoHS II or RoHS-recast) will
most likely cause the elimination of optical materials such as optical glasses, optical filter glasses and
optical glass ceramics [1], which are of vital importance for present and future technical civilization.
To avoid this result it is essential
- to exclude optical materials completely out of the scope of RoHS
- to accept all raw materials for melting optical materials as intermediate substances in the
REACH regulation with ensured legal certainty
This document comprises
- the EU REACH and RoHS regulation references, which threaten the long term availability of
optical materials
- the consequences of these regulations on the availability of optical material types
- the consequences of losses of such materials on optical systems
- the consequences of low performance or missing optical systems on the performance of their
users
EU regulations endanger present and future technical civilization (Details)
as of 11.4.2013
Page 2 of 24
EU Regulation REACH and EU directive RoHS
EU-REACH
The regulation REACH establishes a European legal framework for the registration, evaluation,
authorisation and restriction of chemicals.
Fig. 1 Cover sheet of EU Regulation No. 1907/2006 (REACH) (upper part):
The full text can be downloaded here:
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2006:396:0001:0849:EN:PDF
In its annex XIV REACH is listing substances of very high concern (SVHC). The listed substances will
be forbidden for any further use after a defined sunset date unless it will be authorized or declared to
be an intermediate substance.
Authorization requires procedures, which are highly time consuming and expensive. Granted
authorizations will be restricted in time. Prolongations will require procedures with high effort again.
EU regulations endanger present and future technical civilization (Details)
as of 11.4.2013
Page 3 of 24
With the amendment of REACH annex XIV, EU regulation 125/2012, Arsenic trioxide and Arsenic
pentaoxide have become subject to a sunset date:
Fig 2. Cover sheet of EU regulation 125/2012 (upper part):
Fig. 3 Excerpt of EU regulation 125/2012 with sunset date for As2O3 and As2O5:
Link to download of EU regulation 125/2012:
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2012:041:0001:0004:en:PDF
EU regulations endanger present and future technical civilization (Details)
as of 11.4.2013
Page 4 of 24
EU-RoHS
The EU directive RoHS is listing substances being prohibited for use in electrical and electronic
equipment. Substances on this list relevant for optical materials are Lead and
Cadmium.
Fig. 4. Cover sheet of the 2011 revision of EU directive RoHS, also known as “RoHS-recast”.
The directive can be found here:
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2011:174:0088:0110:EN:PDF
Presently optical materials are exempt from
prohibition due to their listing in annex III of RoHS
until 2016 July 21st as stated in article 5 paragraph
2 of RoHS recast.
Fig 5 Excerpt of EU directive RoHS
Fig. 6 Excerpt of annex III of RoHS recast listing optical and filter glasses:
EU regulations endanger present and future technical civilization (Details)
as of 11.4.2013
Page 5 of 24
Consequences of the EU
U regulattions on the
t
availa
ability of optical material
m
types - Why is thee future use and develo pment of op
ptical materials substan
ntially endan
ngered?
Within th
he REACH re
egulation the
ere is a list o
of substances
s of very high
h concern (S
SVHC), which
h may be
hazardous for living beings, if th
hey become bioavailable
e to an exten
nt surpassingg certain do
ose limits.
Presently the substa
ances Arsenic oxide, Borron oxide and
d Lead oxide
e are on the SVHC cand
didate list,
additiona
al substance
es such as Ca
admium oxid
de are expec
cted soon to be
b on this lisst.
Arsenic oxide and Cadmium
C
oxid
de are only m
minor constittuents with about
a
1 % orr much lowerr content.
Boron o
oxide and Le
ead oxide contents
c
spa
an from abo
out 1 % up to more thhan 50 %. All
A these
substancces are need
ded for optica
al materials and used sin
nce long time
e. Arsenic oxxide has got a sunset
date, Ma
ay 21st 2015
5, a date from
m which on the use and
d placing on the market is prohibited
d [5]. For
Boron oxxide and Lea
ad oxide such
h sunset date
es have to be expected in future alsoo.
With the
e sunset date
e 2015 05 21
2 st for As2O 3 and As2O5 becoming effective
e
thee classical op
ptical flint
glass typ
pes will be forbidden
f
to be produce
ed. This mea
ans the loss of 19 optica
cal glass type
es of the
SCHOTT
T AG glass catalog of high importa
ance for hig
gh end micrroscopy. Forr 56 glass types
t
the
consequ
uence would be a significantly lowe
er performan
nce due to reduced lighht transmiss
sion. The
regulatio
on thus is hittting 75 out of 120 glasss types in to
otal. If the im
mport of Arseenic oxide containing
c
glasses into the EU
E will rem
main allowed
d this would mean that the Euroopean optic
cal glass
manufaccturing indusstry, presently being onlyy Schott AG left over, wo
ould lose its competitiveness and
go out of business. If such glasses would no
ot be allowed
d to be put on
n the EU maarket, for exa
ample the
Europea
an microscop
pe manufactu
urers Carl Ze
eiss and Leic
ca would com
me into troub le and in Europe only
low perfo
ormance miccroscopes wo
ould be availlable any mo
ore with unforeseeable coonsequences
s.
Fig 7 S
SCHOTT opticcal glass portffolio of 2013 w
with Lead and Arsenic conta
aining classicaal flint glass typ
pes (full
rho
ombs), very low
w Arsenic containing glass ttypes (open rh
hombs) and otther glass typees (grey rhom
mbs).
The classsical flint gla
ass types lost are partia
ally hidden in
n the diagram
m because ssome are co
overed by
their rep
placement tyypes. For th
he full range
e see the next
n
diagram
m. For all oof these gla
ass types
replacem
ment glass tyypes have been develop
ped in the 19
990s. They are
a labeled ““N”-glass typ
pes using
Barium, Titanium or Niobium insttead of Lead
d for achievin
ng high refractive index aand Antimony instead
of Arsen
nic as refining
g agent.
The othe
er highlighted
d glass types
s contain Arssenic oxide in
n very low co
ontent (mostlly 100 – 200 ppm).
EU regula
ations endang
ger present and future techn
nical civilization (Details)
as of 11.4.20113
Page 6 of 24
Fig 8. Cla
assical flint gla
asses provide
e unique comb
bination of the properties hig
gh refractive inndex, high tran
nsmission
and speccial partial disspersion. Lead
d oxide conten
nt varies from 0,45
0
% (glass type K7) up too 74% (SF57)), Arsenic
oxide co
ontent is 0,4 % at maximum
m. Like all othe
er constituents
s Arsenic and Lead are firmlly bound in the atomic
networkk of the glasse
es and hence withdrawn
w
from
m biosphere. (16
( data points represent 199 glass types because
for
f three of the
em two quality
y variants exist)
ansmission improving dopant
Arsenic oxide as tra
Figure 9 shows the difference in
n transmissio
on between the Lead-co
ontaining classsical flint glass type
SF57 an
nd its Barium
m-Niobium-Titanium conttaining repla
acement glas
ss type N-SF
F57. HT and
d HTUltra
are imprroved qualityy grade with respect to ttransmission
n. Compariso
on has to bee done along
g vertical
lines. Evven though th
he refractive index and diispersion ma
atches very well
w transmisssion in the blue
b
violet
range is much differe
ent. For applications with
h low blue-vio
olet light leve
els this differeence is decis
sive.
Fig 9. S
SF57 and N-SF57 have the same refractivve index 1,846
666 and dispe
ersion (Abbe nnumber 23,8 ) but very
different transmission in the blue vio
olet wavelengtth range. HTU
Ultra are the va
ariants with thhe highest tran
nsmission
forr each glass ty
ype
EU regula
ations endang
ger present and future techn
nical civilization (Details)
as of 11.4.20113
Page 7 of 24
The impo
ortance of hiigh transmiss
sion in the bllue, violet an
nd near Ultra violet wavellength range is
reflected
d in the ever increasing demand for b est transmission, which has
h led to coontinuous
improvem
ment. This im
mprovement was achieve
ed by using raw
r
material with lower im
mpurity levels
s and
better melting techno
ology.
Fig. 10 The historiccal development of the SF57
7 transmission
n reflects the ever
e
increasingg demand for higher
transmission in the blue vviolet near ultrra violet wavellength range
Blue lin
nes N-LAF Glass Typees
with 0,02 %As O
2
3
Red Lines N-LAF Glass Typees
without As O
2
3
Fig. 11 T
Transmission improvement with very sma
all amounts off As2O3 demon
nstrated with LLanthanum-Flint (LAF)
glass type
es. The transm
mission of glas
sses with a ve
ery small amount of Arsenic
c oxide (200 pppm) is much better
b
than
that of glassses without th
his content.
EU regula
ations endang
ger present and future techn
nical civilization (Details)
as of 11.4.20113
Page 8 of 24
Fig. 12 Trransmission im
mprovement with
w very smal l amounts of As
A 2O3 demons
strated with a Lanthanum-D
Dense-Flint
(LASF) glass type. The
e 0,01 % and 0,02
0
% As2O3 glasses are almost
a
identica
al in remainingg composition
n, whereas
ers also in othe
er constituentss. The contentt of 200 ppm Arsenic oxidee is optimum with
w this
0,03 % version diffe
speciall glass type. The
T 100 ppm version
v
shows a yellow tint, which would be
b observablee in the other versions
v
ger thickness.
only in piecess of much bigg
Prohibitio
on of Arsenicc oxide will le
ead to the lo ss of the ma
ajority of pres
sently existingg optical glass types.
With the
e remaining program op
ptical system
ms will have
e significantly
y lower perfformance if they are
possible at all. The
e glass typ
pes, where Arsenic cou
uld be removed princippally, will lo
ose their
competittiveness aga
ainst equivalent glass tyypes from gla
ass manufac
cturers outsiide the EU. With the
residual glass types it will hardly
y be possible
e to continue
e glass prod
duction in thee EU econom
mically at
all.
EU regula
ations endang
ger present and future techn
nical civilization (Details)
as of 11.4.20113
Page 9 of 24
Other su
ubstances on
o the SVHC
C candidate list: Boron oxide
Boron oxxide is also on
o the SVHC
C candidate list. If this ra
aw material would
w
be proohibited only 28 glass
types wo
ould be possible, see figu
ure 13.
Figure 13: Glass typess remaining if Boron oxide w
would be forbidden. Since fo
or flint glass tyypes both clas
ssical and
and Lead free
e versions are Boron-free a significant num
mber of the blue rhombs coount for two gla
ass types
Arsenic a
each exp
plaining the diffference betwe
een the quote
ed number of 28
2 types and 20
2 types counttable from the
e diagram.
19 of the
e remaining glasses
g
are the
t classical flint glasses containing Arsenic
A
oxidee and Lead oxide.
o
Combined prohibitiions reduce
e glass type portfolio to
o negligible size
s
Boron oxxide prohibition together with Arsenicc oxide leave
es only 6 gla
ass types ovver from the presently
120 see figure 14
Fig. 14 Remaining
R
gla
ass types if Bo
oron oxide and
d Arsenic oxide would be prrohibited.
EU regula
ations endang
ger present and future techn
nical civilization (Details)
as of 11.4.20113
Page 10 of 24
With all B
Boron, Arsen
nic or Lead containing
c
gla
ass types rem
moved the to
otal optical g lass program
m would
shrink to
o 5 glass type
es see figure
e 15.
F
Fig. 15 Remaining glass typ
pes if Boron oxxide, Arsenic oxide
o
and Lea
ad oxide wouldd be prohibited
d.
EU regula
ations endang
ger present and future techn
nical civilization (Details)
as of 11.4.20113
Page 11 of 24
Zero-expansion glass ceramic ZERODUR®
The zero-expansion material ZERODUR® is a Lithium-Aluminum-Silica glass ceramic with Arsenic
oxide content below 1 %. Its composition has not been changed since its introduction 45 years ago.
The zero-expansion effect depends critically on the amount and size of micro crystals embedded in
surrounding glass. The micro crystals shrink and the glass around them expands when being heated.
With a very special equilibrium between micro crystal content and surrounding glass overall zeroexpansion can be achieved.
The controlled embedding of micro crystals of well-defined size and number per volume in residual
glass is achieved by melting the base glass with a process derived from optical glass manufacturing.
In a subsequent tempering process first crystallization nuclei are created and secondly crystals are
grown to the required size.
®
Fig. 16: ZERODUR : 2 m glass ceramic disk (left), micro crystals embedded in residual glass (right)
The growing application of ZERODUR® in high technology devices comes from the fact that SCHOTT
is able to produce very large (up to 4 m) and thick volumes (up to 1 m) with extreme tolerances with
respect to zero-expansion and its homogeneity throughout the total volume. The material is
reproduced with all its properties to an outstanding level. From a large variety of applications the
material properties are well-known to very high precision and with a 45 years’ experience.
The reliability of its production process comes from mastering the melting, casting and precision
tempering processes. However, this is not sufficient. Composition also plays a critical role. Even slight
changes may have large consequences. Nucleation and crystal growth are very sensitive in this
respect. Removing Arsenic oxide from the composition might lead to severe restrictions in producible
size and thickness. Proving the suitability of different compositions can be done only with production
size melting lots with one test costing more than 1 million € and lasting more than one year.
From a variant produced in the past under the name ZERODUR M® one knows that even small
changes in composition lead to significantly different properties. So a ZERODUR® without Arsenic
oxide, even if it would be producible at all in the required sizes, would have to be re-qualified for all
applications critical for safety such as ring laser gyroscopes for airplanes or critical for performance
such as microlithography and all other, which require predictable material behavior over long time with
utmost precision. An Arsenic free ZERODUR® will force many users to perform time and money
consuming qualification tests just to maintain the present state-of-the-art. This will impair present day
production and progress in high-tech industry significantly.
ZERODUR® is a vital material for all high technology applications, where temperature difference
induced length changes and resulting warp pose the final limit for the achievable precision:
Structural elements in microlithography equipment, optical elements for flat screen lithography, ring
laser gyroscopes for airplanes, linear scales for precision length measurements, extreme precision
measurement devices, calibration standards and mirrors in weather satellites, for earth observation
and for astronomical research.
EU regulations endanger present and future technical civilization (Details)
as of 11.4.2013
Page 12 of 24
Colored filter glass types
There are different coloring mechanisms with glass filters. In the blue and green filter glasses Cobalt
and Copper ions act as absorbing agents. Heat absorbing filter glasses use Iron ions. In white filter
glasses the natural UV-absorption edge is used. The yellow, orange and red steep slope filter glasses
use a different coloring mechanism. They contain Cd-compounds (oxides, sulfides and selenides) with
a Cd-content of max. 1.5 weight-% forming semiconductor micro crystals. The very desirable steep
slope filter characteristic, which can be positioned throughout the total visible spectrum to the near
infrared, is unique for the Cadmium containing glass types.
B2O3
UG5
UG11
BG3
BG7
BG25
BG55
BG60
BG61
BG62
BG63
BG64
BG65
BG50
BG55
GG395
GG400
GG420
GG435
GG455
GG475
GG495
OG515
OG530
OG550
OG570
OG590
RG9
RG610
RG630
RG645
RG695
RG715
RG715
RG1000
NG1
NG3
NG4
NG5
NG9
NG11
N-WG280
N-WG295
N-WG305
N-WG320
KG1
32
6
PbO
CdO
UG1
UG5
UG11
BG3
BG7
BG18
BG25
BG36
BG38
BG39
BG40
BG42
BG50
BG55
BG60
BG61
BG62
BG63
BG64
BG65
UG1
UG5
UG11
BG3
BG7
BG18
BG25
BG36
BG38
BG39
BG40
BG42
BG50
BG55
BG60
BG61
BG62
BG63
BG64
BG65
VG9
As2O3/
CdO
UG5
UG11
BG55
BG60
BG61
BG62
BG63
BG64
BG65
GG395
GG400
GG420
GG435
GG455
GG475
GG495
OG515
OG530
OG550
OG570
OG590
RG9
RG610
RG630
RG645
RG665
RG695
RG715
RG780
RG830
RG850
NG1
NG3
NG4
NG5
NG9
NG11
N-WG280
N-WG295
N-WG305
N-WG320
KG1
KG2
KG3
KG5
57
As2O3/
B2O3/CdO
BG55
RG1000
NG1
NG3
NG4
NG5
NG9
NG11
N-WG280
N-WG295
N-WG305
N-WG320
KG1
KG2
KG3
KG5
37
RG1000
NG1
NG3
NG4
NG5
NG9
NG11
N-WG280
N-WG295
N-WG305
N-WG320
KG1
14
1
PbO/CdO
UG1
UG5
UG11
BG3
BG7
BG18
BG25
BG36
BG38
BG39
BG40
BG42
BG50
BG55
BG60
BG61
BG62
BG63
BG64
BG65
RoHS
UG1
UG5
UG11
BG3
BG7
BG18
BG25
BG36
BG38
BG39
BG40
BG42
BG50
BG55
BG60
BG61
BG62
BG63
BG64
BG65
VG9
GG395
GG400
GG420
GG435
GG455
GG475
GG495
OG515
OG530
OG550
OG570
OG590
RG9
RG610
RG630
RG645
RG665
RG695
RG715
RG780
RG830
RG850
RG1000
NG1
NG3
NG4
NG5
NG9
NG11
N-WG280
N-WG295
N-WG305
N-WG320
KG1
KG2
KG3
KG5
58
As2O3
REACH
All Glass
Types
NG1
NG3
NG4
NG5
NG9
NG11
N-WG280
N-WG295
N-WG305
N-WG320
KG1
KG2
KG3
KG5
35
Table 1: All colored filter glasses of the present SCHOTT catalog in the first column. The second column shows
the remaining glass types with Arsenic oxide being forbidden, the following columns the remaining glass types
with Boron oxide, Lead oxide or Cadmium oxide being forbidden. The three last columns show the effect of
combined prohibitions with the second last being equivalent to the case, when REACH SVHCs will be forbidden.
The last column stands for prohibitions without RoHS exemptions. With RoHS prohibitions being effective about
half of all glass types will be eliminated, all yellow, orange and red ones. REACH prohibitions mean the total end
of all colored filter glass types.
EU regulations endanger present and future technical civilization (Details)
as of 11.4.2013
Page 13 of 24
In order to achieve best
b
filter characteristics it is importa
ant to combin
ne a suitablee base glass
s with the
coloring dopant. One
e is not free to choose ssince there are
a only few chemical eleements colorring glass
in the de
esired way and if they do
o it right depe
ends on the surrounding atoms. This leads in ma
any cases
to glasse
es, where co
ompromises have
h
to be m
made with res
spect to theirr thermal exppansion behavior and
their che
emical endurrability. Rese
earch for besst performan
nce glass typ
pes lasts withh the glasses
s as long
as for op
ptical glassess, about 130 years.
Replace
ement pos
ssibilities
Some re
eplacement was already
y done in tthe 1990s, when
w
Arsenic oxide haad been rep
placed by
Antimony oxide as refining
r
agent in optical glass for th
he removal of
o bubbles. However, du
ue to the
requirem
ment for very high transm
mission some residual Ars
senic oxide in
n concentrattions around 100 ppm
remainin
ng in the gla
ass matrix ha
ad to be ma
aintained. The transmissiion improvem
ment effect is unique
with Arse
enic. Together with Lead
d oxide in cla
assical flint glass types it is essential ffor the combination of
high refrractive indexx and high trransmittance
e in the blue
e violet spec
ctral range, w
which is ess
sential for
fluoresce
ence microsscopy, a me
ethod of vita
al importanc
ce for all medical
m
and biological research.
r
Replacement glass types
t
have significantly
s
lo
ower perform
mance even after long annd intensive research
for better alternativess for almost three
t
decade
es.
Fig. 17 Lead arseniic free glass ty
ypes introduce
ed since 1998
8 to the optical glass portfolioo (blue rhomb
bs) and
rem
maining classiccal flint glass types
t
(green dots)
d
The intro
oduction of Boron
B
oxide into glass th
hus forming borosilicate glass types by Otto Sch
hott about
130 yearrs ago was one
o of the most
m
importan
nt steps in gllass development in geneeral and esp
pecially in
optical g
glasses. It en
nabled widen
ning the glasss program to the exten
nt that high eend diffractio
on limited
optical ssystems became possible. There is no replacem
ment for Boro
on oxide in glass manuffacturing.
Such prrohibition wo
ould throw glass
g
producction 130 ye
ears back in time. Beyoond optics th
his would
eliminate
e all heat resistant and chemically
c
re
esistant glas
ss types (Du
uran, Boroflooat, Pyrex,…) used in
chemistrry, pharmace
eutical packaging, illumiination, fire protection, solar
s
thermaal technology
y and as
kitchenw
ware.
EU regula
ations endang
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For the zero-expansion glass ceramic ZERODUR® it is not known, if an Arsenic free version could be
molten and cast in such large pieces (1 meter and larger) of outstanding quality as needed by
microlithography and flat panel production. For these applications and especially safety relevant
applications such as laser gyros for airplanes material qualification procedures would have to be done
again. All application experience would be lost and would have to be gathered again. There is a nonnegligible risk, that a replacement material would not fulfill the requirements. Anyhow the development
effort requires such long time period, that it would impede progress in many fields such as computer
technology and its related fields in general for years.
There has been a long and intensive research on the possibility of replacing Cadmium in the steep
slope filter glasses. All alternatives have much lower performance and use materials containing
substances, which are also endangered by possible prohibitions such as Selenium oxide, Arsenic
oxide or Antimony oxide.
Arsenic containing chalcogenide infrared glasses enable cost-effective night vision safety applications,
which would not be realized if only the existing but very expensive IR materials could be used.
Hazard from optical materials
Optical glasses, filter glasses, glass ceramics and infrared materials are molten from well- defined
mixtures of raw materials. Generally they are substances of variable compositions, which are
expressed by convention as oxides of the constituent elements (for example: SiO2, Na2O, CaO, B2O3).
However, they are not a mixture of individual compounds such as metals or oxides. In fact glass is a
non-crystalline inorganic macromolecular structure. During the melting process the raw materials react
creating a new chemical substance totally different from the starting materials. The physico-chemical,
toxicological and eco-toxicological properties of the substance glass are totally different from those of
the raw materials or oxides.
Under REACH, glass is classified as a UVCB substance (substance of unknown or variable
composition, complex reaction products or biological materials – Annex V (11) REACH). It is exempted
from the REACH registration requirement under certain conditions laid down in Annex V (11) REACH.
Separation of glasses back into their elements or their oxides is possible only with special high effort
and does not occur in reality. Just like all other glass constituents Arsenic oxide, Boron oxide and Lead
oxide are withdrawn from bioavailability in this way and mean no harm to human beings and the
biosphere anymore.
Raw material supply, melting process and subsequent transforming to optical elements such as lenses
and prisms are done under strictly controlled environmental, health and safety procedures enforced by
permanent surveillance and regular auditing.
In the state of bulk pieces glass is of no hazard at all.
Moreover the total production volume of inorganic optical materials is so small that all risks related to
their production and usage are very confined with respect to locations and periods.
Individual authorization and applications for exemptions
The present catalogs of Schott AG comprise more than 170 different optical materials roughly the
same number of special variants of optical materials produced out of about 100 different raw materials
containing about 50 chemical elements. For many optical materials the production volumes and
hence turn-overs are very small. Neither an authorization nor an exemption application nor a
redevelopment would be economically justifiable, if technically feasible at all. Individual treatment of
glass types, raw materials or chemical elements would evoke the end of optical material production
and consequently the end of the optical industry and all related technology, which in the end is all
technology in general.
Even if substances would be exempted or authorized uncertainty would continue due to the ongoing
addition of substances to the REACH SVHC list and RoHS prohibition list.
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Manufacturing outside the EU
One solution at first glance might be moving the production of optical materials outside the EU since it
will be allowed to import optical materials containing SVHCs in the future. This runs the risk of supply
restrictions due to ITAR in the US or monopoly situations as occurred with rare earths from China
recently. Since the optical industry in Europe is a high performance highly competitive industry, their
supply with the vitally essential optical materials cannot be moved outside deliberately. The candidate
countries USA and especially Japan and China have optical industries of their own competing with the
European. So it cannot be expected that the European optical industry will get optical materials of
such high quality as they would need to remain competitive.
From European defense considerations the situation to depend on foreign supply of material with such
strategic importance as optical materials is merely unthinkable.
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The vital importance of optical materials
Optical systems provide key functions for research, diagnosis, surveillance and quality assurance in
medicine, scientific research, general industry, safety installations, environment monitoring and a vast
amount of other applications. For example without leading edge microscopes progress in medicine
and microbiology is impossible.
The applications of optical systems reach far beyond the classical fields of microscopic and telescopic
viewing. All industry relies on the function of high end optical systems. Automotive, aviation, ship
building industry, road and building construction, even food industry need optical measurement
equipment for machine alignment and for quality inspection. Theodolites and laser trackers provide
precision measurement capabilities for large objects.
Pics.: Leica Geosystems
There is a well-known rule in industry: What cannot be measured cannot be manufactured. Optical
systems are ubiquitous in metrology and not replaceable. Optical materials provide the key functions
of optical systems such as refraction, reflection, selective transmission and more. If optical materials
would get lost optical systems would become worse in performance or even get lost also with
incalculable consequences for all science and technology relying on them.
For this reason photonics has been recognized as key enabling technology within the new EU
program Horizon 2020. For more information about the application of optical systems see for example
the reports of the US National Academy Report: “Optics and Photonics, Essential Technologies for
Our Nation” also known as “Harnessing light II” and of the association Photonics 21 “The Leverage
Effect of Photonics Technologies” .
Requirements on optical imaging systems
Optical imaging systems such as microscopes, telescopes and photo cameras have to fulfill high
requirements on rendering images with fine details (high resolution), without distortions and without
changing colors (color trueness). Additional application specifications such as focus ranges, zoom
ranges, working distances, matching to detectors (CCD-and CMOS-chips) of different sizes, and many
more lead to complex designs with many lenses of different shapes and different materials to enable
optimization of all specification characteristics simultaneously. The optimization procedure is difficult
since not many variables can be changed. Only the lens shapes, their relative distances and their
material can be varied. Significant progress in optical design computing and lens production has made
outstanding optical systems become available. All this progress is lost when the optical material basis
is weakened.
Color trueness
High color trueness is the main reason for the requirement of a large variety of optical glass types.
It is not just a matter of aesthetics but in many applications it is decisive for success or complete
failure. For example the quality of imaging color for medical applications has to be extremely good to
recognize cancer tissue in surgery. A bad reproduction of color in the image forming instrument is not
acceptable, since cancer tissue is recognized primarily by small color differences.
Only sophisticated combinations of lenses from glass types with different refractive index dependence
on light wave length result in true color images. Requirements increase since optimum imaging is
needed over an extending spectral range.
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From the viewpoint of optics, there are two different effects, if the color trueness is not achieved to the
necessary standard:
1.
2.
Different lateral magnification for different colors causing color fringes in the image
Axial focus differences leading to a sharp image only for one color.
Usually green is made good, the red and the blue images
are blurred and badly resolved.
In both cases resolution is getting worse. Fine details cannot be recognized anymore.
Additionally image colors may change if optical glass does not transmit light of all wavelengths to the
same extend. Higher refractive index glass types tend to absorb blue, violet and ultra-violet stronger
than other colors. The effect increases strongly when the light path in such glass is long, which means
several centimeter or more. Compensation of this color change by higher illumination is normally not
possible since lamps usually have also lower light emission in the blue violet range and some object
are very sensitive against the high energy irradiation with blue light. These are especially biological
objects.
Lead and arsenic containing optical glass
The lead and arsenic containing dense flint glasses have a unique combination of the properties high
refractive index, high transmission in the blue and violet wavelength range and special partial
dispersion. Therefore these materials are indispensable for many high performance systems.
Lead and arsenic containing optical glass types are crucial for many different important
applications:
1. Microscopes for life, bio and material science as well as medical applications are widely
used in hospitals, research laboratories and industry.
2. Near UV-region fluorescence microscopy (excitation of fluorescence with UV-light needs
high throughput of UV-radiation), optical investigations and diagnosis in the near UVregion (bio-fluorescence, gene analyses, print-scanner).
3. Surgical microscopes need high color trueness even if light has to travel through long
glass paths.
They are used by surgeons, neurosurgeons and dentists in order to control operations. In
using such a surgical microscope the surgeon gets a magnified view of the operation field
which allows for a better control of the operation and also a better separation of sound
and damaged tissue.
4. Endoscopes for minimally-invasive surgery or technical inspections. They also need high
color trueness over glass paths, which are much longer than in microscopes, especially
no blue-violet transmittance losses for reliable tissue recognition). The ban of lead glass
would endanger the achievements of the minimum invasive surgery.
High quality technical endoscopes are widely used for industrial inspections e.g. for the
inspection of aircraft jet safety.
5. Ophthalmic instruments (color trueness over long glass paths)
6. Medical x-ray diagnosis equipment needs image intensifiers with the CCDs shielded
against the x-rays. This can only be achieved by using lead containing flat and optical
glass in combination since lead glass efficiently absorbs x-rays. The same holds for
electron microscopes.
7. Temperature compensated high end optical imaging systems for medical and printing
applications need the specific behaviour of lead glasses in changing its index of refraction
and dispersion with temperature changes.
8. Lead containing glass fibers (highest blue-violet-ultraviolet transmittance) Lead containing
fibres enable high quality illumination units for operation microscopes used for
microsurgery.
9. High end photography (color trueness over long glass paths). Interchangeable lenses for
photographic applications with Pb-containing lens elements are used in combination with
photo cameras.
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10. Cinematographic camera lenses (color trueness over long glass paths)
11. Movie projection lenses (color trueness over long glass paths, energy saving by reducing
heat losses)
12. Digital projection SF57 (best color trueness from the very start of the projection due to
insensivity of this unique glass type against heat induced birefringence, energy saving by
reducing heat losses).
In digital projection (beamers) SF57, a highly lead
containing glass type, is unique for its property, not to convert thermo-mechanical
stresses into birefringence. There are no other glass types with this property to the extent
of SF57. Especially for this application in the years 2000 – 2005 intensive R&D effort has
been undertaken by all glass manufacturers, since it would have been a great marketing
advantage to provide a lead-free glass type with similar properties like SF57 (stressoptical constant equal to zero, refractive index > 1.8, good workability and low price).
However nobody found a replacement solution, which fulfilled the requirements.
13. Photolab equipment (color trueness over long glass paths)
14. i-line microlithography (high refractive index and high transmission in the UV for extreme
resolution)
15. With optical systems designed for telecom applications in the near infrared (1000 – 1500
nm) the eco versions of the lead containing glasses are no equivalent substitutes since
here the optical properties differ significantly from the predecessor types. The eco
versions have been developed only for the visible region.
Microscopy and Medical Systems
Microscopic objective lenses need a
high performance color trueness.
Carl Zeiss Axioskop 40
Otherwise, the critical applications of
biological
research,
medical
diagnostics, drug discovery etc. are not
possible.
The quality of imaging color for
medical applications has to be
extremely good to recognize cancer
tissue in surgery. A bad reproduction
of color in the image forming
instrument is not acceptable, since
cancer tissue is recognized primarily
by small color differences.
In modern microscopy applications
special imaging methods become
increasingly important, which need a
Pic.: Carl Zeiss
broad spectral transmission from the
ultraviolet through the visible to the
near infrared light. Typically, nonlinear processes are used to make biological effects visible with the
help of marker substances. These materials typically have a quite low density and only little light can
be observed as a signal. Therefore a high transmission is necessary to perform these applications.
Some very import examples are:
•
•
Fluorescence Microscopy is used
in Haematology
Pathology
Zytology
Gynaecology
Cancer research, diagnosis and surveillance examinations
Environmental diagnosis
Food surveillance
Biological research
Raman microscopy for biological research
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Low radiation
applications:
-
loading of the samples is necessary to prevent damage and bleaching in the
Cancer and AIDS research
Drug discovery
Clinical diagnostics
Pathology
Transmission in the Ultraviolet (UV) spectral region
Lead, Arsenic-free glasses and optical systems made from such glasses have a strongly reduced
transmission from 410 ...365 nm and no transmission below 365 nm. However, obtaining a sufficient
amount of light in this range is essential for many very important applications.
Photon gain from fluorescence and Raman effects is very low due to the fundamental physics of these
processes. So it is of utmost importance to have an optical system within the microscope to reduce
optical losses to the absolute minimum. Increasing the power of illumination systems in order to
compensate for transmission losses in the optical system is no option due to inherent increasing
temperatures of the overall optical system with subsequent thermal instabilities and because many
samples, especially from life and bio sciences, have to be observed under strictly controlled and
moderate temperature conditions; otherwise they will be altered or worst-case destroyed during the
observation.
A typical microscopic lens design for broad spectral applications with Pb, As-containing glasses results
in an overall transmission of 94% at a wavelength of 365 nm (UV-region); if there would be a switch to
Pb, As-free glasses, the transmission will fall down to an unacceptable level of only 40%. This is far
too low for these microscope applications to be performed with reasonable throughput and quality.
Zero-expansion glass ceramic ZERODUR®
ZERODUR® is a vital material for all high technology applications, where temperature difference
induced length changes and resulting warp pose the final limit for the achievable precision. A one
meter rod of steel expands 1000 nanometers being heated up by 0.1 °C a rod of the same length from
the best quality grade of ZERODUR® expands less than 1 nm. Applications with such requirements
are significantly growing:
1. Structural elements in microlithography equipment (wafer steppers for IC-chip production):
Frames for masks with lithographic pattern to be imaged onto silicon wafers (“reticle stages”).
Support frames for silicon wafers (“wafer stages”) for utmost positioning tolerances of 1 nm for
a 300 mm wafer. Reference mirrors for position monitoring.
2. Optical elements for flat screen lithography transferring electronic control wiring for image
pixels from a mask to flat screen substrates.
3. Structural body and precision mirrors for laser gyroscopes for position control of airplanes as
important safety feature.
4. Linear scales for precision length measurements in CNC production and measurement
machines enabling large series precision production of complicated metal structures such as
motors, brakes, gearboxes in automotive, aviation, ship and railway industry.
5. Extreme precision measurement devices: atomic force microscopes, geodetic gyroscopes,
optical benches in fundamental research
6. Calibration standards for linear, 2D- and 3D measurements.
7. Mirrors in weather satellites and for earth observation
8. Mirrors for astronomical research (Large earth bound telescopes up to 8 m monolithic,
extremely large telescopes up to 39 m (in planning), airborne infrared telescope and spaceborne x-ray telescopes
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Cadmium containing glass types
The Cadmium-containing yellow, orange and red filter glass series (the GG, OG, RG-glass
types) are used because of their unique technical properties:
-
They provide a set of steep-slope long pass filters
covering
a
wide
range
of
wavelengths.
The position of the absorption edge may vary from
395 nm up to 850 nm. That is the total visible range
and part of the near infrared. This enables short
wavelengths blocking at the desired cut-off
wavelength in a very flexible, convenient and efficient
way.
-
The blocking ratios in the absorption range better than
105 are unequalled by any other bulk filter solutions.
This is required especially in laser safety applications
and sensitive measurement methods relying on high signal to noise ratios.
-
They maintain their colorimetric properties even under harsh conditions (temperature shocks
from lamp switching, direct weather exposition) over long time periods and independent of
viewing angles. This is required by air traffic safety regulations (runway illumination). There
are no alternative solutions.
-
They maintain their filter characteristic over long time periods without any bleaching, from
which all plastic filter products suffer.
-
They can endure significantly higher temperatures than plastic filters, which are limited to
about 150°C. With illumination applications such temperatures will easily be reached.
-
They maintain their filter characteristics almost independent from the angle of light incidence,
which may be a significant advantage over filters made with interference coatings, which
exhibit a significant angular dependence of their spectral characteristics. This is especially
important if the filter is located at a position where light beams are strongly convergent or
divergent.
-
Interference coatings and cd-containing long pass filters together provide optical filter
solutions, which combine the specific advantages of the individual components (effective
absorption of color glass filters and the reflection properties of taylor-made interference
coatings).
Cadmium containing glass types provide unique filter characteristics for important
applications such as:
1. Robust airport and traffic illuminations, low environmental sensitivity (color trueness of airport
traffic control lighting) Airport runway safety illumination (well defined signal color independent
from viewing angle, long term resistance against environmental influences (weather) and
severe temperature changes due to lamp switching. Therefore such filters need to be
toughened by prestressing, which is only possible with glass filters.
2. Facility safety surveillance (Invisible infrared illumination through deep red long pass filters)
3. Generation of sharp edged filter curves for many spectroscopic applications, insensitive to
temperature and incidence angle and a high separation ratio
4. Eye glasses for laser protection (high blocking capability, filter edge insensitive against
incident light angle) Safety equipment e.g. laser protection eye glasses especially according to
European and German standards prescribing the assurance of long-term safety function.
Plastic filters may suffer from holes burnt in and long-term filter effect degradation.
5. Traffic observation and monitoring systems, speed limit enforcement (cameras to take pictures
of drivers surpassing the speed limit), toll monitoring systems
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6. Environmental surveillance, satellite photography and multispectral mapping of water
constituents in lakes. Optical systems in Waste sorting facilities, waste water analysis,
exhaust gas analysis, airborne (airplanes, satellites) environmental diagnosis photography.
7. Color channel separation in TV and general color visualization and display systems
8. Photographic colour filters.
9. Industrial and technical inline and motion measurement, camera and control systems
10. Telecommunication: Attenuation or separation of undesired wavelengths transmitted by
coated filters (side bands)
11. Light barriers for motion control (busses, elevators,…) Bar code readers
12. Logistics automation equipment (automatic reading units, letter sorters, parcel sorters ...)
13. Industrial measurements: Well blocked band pass filters are made with thin film interference
coatings, which provide the band pass characteristics, whereas additional glass filters
effectively suppress the undesired transmission regions outside the bandpass, which is typical
with multiple wavelength interference.
In industrial measurement frequently blocking ratios outside the bandpass are necessary,
which only Cd-containing filter glasses can provide
14. Industrial displays: contrast enhancement, signal effect, improved resolution, better reading.
15. Detection of faked paintings
16. General research (filter wheels, filter monochromators, astronomy filter sets for different
observation wavelength bands). In general scientific systems with critical spectroscopic
detection principles
17. Performance of applications requiring a necessary high signal-to-noise ratio (SNR) in a special
range of the wavelength.
Requirements from optical industry
Optical systems for professional use and nowadays even for consumer applications are designed for
utmost performance. Images must be highly resolved with lowest distortions and optimized for true
color rendering. High light sensitivity is required together with large focusing range. There is an
increasing number of applications, where systems must perform on the extreme level over a
wavelength range extending from the ultraviolet over the visible range to the infrared light.
Such applications require high performance high quality glass types. Because of the manifold of
different applications and thus many specially designed optical systems a large number of glass types
with significantly different properties is needed. This can only be achieved by using typically 6 to 10
chemical elements per glass type out of a total set of more than 50 chemical elements being used in
optical glass, filter glass and glass ceramics production.
Optical system designs need typically two years from start to first glass purchase. In high end
industrial optics the glass types used must be available for at least ten years, as industry needs supply
chain security. In defense, medical and lithography applications periods may extend to even thirty
years.
All exemptions and authorizations with expiry dates will increase uncertainties in glass availability
while approaching the expiry dates.
Presently there is EU funded optical research aiming to improved products in the future. Within the
framework program Horizon 2020 EU will increase funding significantly to many billions of Euros to be
spent within 2014 and 2020. Time and money for such development will be wasted, when it relies on
materials, which will be prohibited by the time, when development results could be converted to
products. So researchers and developers would have to avoid such materials from the beginning of
their research. This might lead to preventing gradual and revolutionary progress in the EU, while other
countries outside the EU without such restrictions will be able to leave the EU behind. To make things
even worse the continuously increasing number of materials to be prohibited makes the list of
materials to be avoided in research and development to a moving target destroying any reliable basis
of such work.
Optics industry needs guaranteed long time availability of all optical materials.
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What to do?
-
The optical materials optical glass, filter glass and optical glass ceramics must be taken totally
out of the scope of RoHS.
All chemical raw materials needed for the manufacturing of optical materials must be assigned
to be intermediate substances with ensured legal certainty to guarantee their future
availability.
An intermediate substance is defined in REACH as “a substance that is manufactured for and
consumed in or used for chemical processing in order to be transformed into another
substance”. This applies to all glass raw materials. The raw materials are already subject to
stringent health and safety procedures. Any REACH authorization requirements will not
contribute to further risk reduction but cause vast damages in technical civilization. Therefore
they must be avoided.
Mainz, 11.4.2013
Dr. Peter Hartmann
Advanced Optics
SCHOTT AG
References
P. Hartmann, “Optical glass, optical filter glass and optical glass ceramic –Definitions”, 2010
Horizon 2020 website “Competitive Industries”:
http://ec.europa.eu/research/horizon2020/index_en.cfm?pg=competitive-industry
US National Academy Report: “Optics and Photonics, Essential Technologies for Our Nation” also
known as “Harnessing light II”
http://www.nap.edu/catalog.php?record_id=13491
http://spie.org/x88993.xml
Photonics 21 report “The Leverage Effect of Photonics Technologies”
http://www.photonics21.org/downloads/download_brochures.php
EU Commission Regulation (EU) 125/2012 REACH Annex XIV Amendment
P. Hartmann, “Optical glass: past and future of a key enabling material“
Adv. Opt. Techn., Vol. 1 (2012), pp. 5–10
P. Hartmann, Uwe Hamm, “Optical glass and the EU directive RoHS“,
Proc. SPIE 8065, p.806511, (2011)
Technical Adaptation under Directive 2002/95/EC (RoHS) – Investigation of Exemptions; P. Goodman;
ERA-Report 2006-0603; ERA Technology Ltd., December 2004
Bach, Neuroth et. al.; The Properties of Optical Glass, Springer, Berlin, 1995
Input from Schott AG; Dr. P. Hartmann and Dr. K. Loosen; 28.02. – 06.03.2008
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M. Laikin, Lens Design, CRC Press, 2007, p. 12
S. Zhang, R. Shannon, Opt. Eng. 34 (1995), p. 3536, Lens design using a minimum number of glasses
R. Fischer et. al. , Proc. SPIE 5524(2004) p. 134, Removing the Mystique of glass selection
W. Klein, Jahrbuch Optik und Feinmechanik, 1981, p. 144, Glasauswahl bei der Berechnung optischer
Systeme
W. Besenmatter, Proc. SPIE 3482, (1998) p. 294, How many glass types does a lens designer really
need ?
T. Sure et. al., Proc. SPIE 6342 (2006), No. 63420E-1, Ultra High Performance Microscope Objectives
- The State of the Art in Design, Manufacturing and Testing
R. Shi et. al., Photonik 5 (2004), p. 62., Design-Aspekte zu planapochromatisch korrigierten
Mikroskopobjektiven für Auflichtanwendungen
Review of Directive 2002/95/EC (RoHS); Categories 8 and 9; Final Report; P. Goodman, ERA
Technology Ltd., July 2006
Second EU-stakeholder consultation on the Review of Directive 2002/95/EC (RoHS), 11/2007
J. Freund; „Herstellung von CdSxSe1-x - gefärbten Anlaufgläsern durch einen Sinterprozess“ PhDThesis, University of Saarland, Saarbrücken 2003. in English „Production of CdSxSe1-x – colored
temper glass types via a sinter process.“
Y. Zhou, Integrated planar composite coupling structures for bi-directional light beam transformation
between a small mode size waveguide and a large mode size waveguide, United States Patent
7218809 (2007)
Y. Zhou, Varying refractive index optical medium using at least two materials with thicknesses less
than a wavelength, United States Patent 20050036738 (2005)
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