Technical information

5
1
A
n
d
so we
di
st
i
n
g
u
i
s
h
b
etween t
h
e v
i
sua
l
pat
h
, re
-
sponsible
f
or all visual tasks such as reco
g
nizin
g
pic
-
tures, perce
i
v
i
n
g
b
r
igh
tness, contrast, s
h
apes, etc.,
an
d
t
h
e non-v
i
sua
l
pat
h
, or a
l
so
“bi
o
l
o
gi
ca
l
pat
h”
,
w
hi
c
h
contro
l
s
i
n part
i
cu
l
ar t
h
e c
i
rca
di
an r
hy
t
h
ms an
d
also in
f
luences in the daytime our alertness and men-
tal per
f
ormance and also biological
f
unctions such
as
h
ormone pro
d
uct
i
on, t
h
e
bl
oo
d
c
i
rcu
l
at
i
on an
d
t
h
e
m
e
t
abolis
m
.
The non-visual path is essentiall
y
independent o
f
the
v
i
sua
l
p
at
h
.
S
cientific studies
(
Prof. Brainard, Thomas Jefferson
Universit
y
, Philadelphia
)
have established that mela
-
tonin suppression depends not only on brightness but
also on the wavelen
g
th o
f
the li
g
ht used. Li
g
ht in the
blue spectral ran
g
e o
f
about 460 nm has the stron
g
est
e
ff
ect on suppressin
g
melatonin
.
The course o
f
the sensitivit
y
curve measured b
y
Brain-
ard
f
or melatonin suppression shows no correlation to
the course o
f
the previousl
y
mentioned e
y
e sensitivit
y
curves
f
or the red,
g
reen or blue photoreceptors in the
eye.
This made it apparent that there is a
f
urther previousl
y
unknown type o
f
li
g
ht-sensitive cell in the eye respon
-
sible
f
or the circadian e
ff
ect o
f
li
g
ht
.
Prof.
G
all from the “Lichttechnisches Institut” at the
University o
f
Ilmenau has reco
g
nized that the sensi-
tivit
y
curve
f
or melatonin suppression published b
y
Brainard is ver
y
similar to the known curve V
(
λ
)
which
describes eye sensitivity for seein
g
bri
g
htness.
O
nly
the s
p
ectral
p
osition is shi
f
ted towards blue
.
The curve C
(
λ
)
, su
gg
ested by Gall, serves today as the
f
oundation
f
or a measurin
g
system
f
or circadian li
g
ht
-
in
g
data, de
f
ined in DIN V 5031-100. These wei
g
htin
g
fac
t
o
r
s
ca
n
be
t
a
k
e
n int
o
accou
nt in
o
r
de
r t
o
co
n
s
i
de
r
the biolo
g
ical effect of li
g
ht sources
.
spectral sensitivity
wavelength [nm]
circadian function
visual sensitivity
Fig. 54: Definition of a circadian function C(
λ
(
(
) by Gall
λ
et. al. in analogy to the photometric function V(
λ
(
(
) as
λ
standardized b
y
the
C
IE.
8
.4
UV
ra
di
at
i
o
n
T
he metal halide lam
p
standard IE
C
61167 describes
the e
ff
ective UV-radiation out
p
ut and s
p
eci
f
ies limit
va
l
ues
i
n t
h
e respect
i
ve
l
amp
d
ata s
h
eets.
Thi
s
m
eans that the UV radiation o
f
the lamp in the ran
g
e
250 – 400 nm
i
s we
igh
te
d
w
i
t
h
a so-ca
ll
e
d
eva
l
uat
i
on
function
(
see fi
g
ure 55
)
(
similar V
(
λ
)
-evaluation of
visible radiation
)
.
Thi
s eva
l
uat
i
on curve s
h
ows t
h
e
g
enera
li
ze
d
sens
i
t
i
v
i
ty
o
f
human tissue to UV radiation over wavelen
g
th and
h
as been defined b
y
the I
C
NIRP
(
I
n
t
e
rn
a
t
io
n
al
C
om-
mi
ss
i
o
n
o
n
N
on-
I
onizing
R
ad
i
a
ti
o
n
P
rotection
).
Thi
s eva
l
uat
i
on curve
i
s use
d
to
d
a
y
by
near
ly
a
ll
na-
tional and international bodies
(
standardization, pro-
fessional associations, etc.
)
. The A
CG
IH
(
A
m
e
r
ica
n
C
o
n
fe
r
e
n
ce
of
G
overnmental Industrial Hy
g
ienists
)
uses this evaluation
f
or workplace guidelines
.
T
he NI
OS
H
(
National Institute for
O
ccupational Health
and
S
afet
y)
is an American federal authorit
y
that re-
searches occupational health and sa
f
et
y
and issues
correspondin
g
recommendations
.
T
he maximum daily dose
(
8h workin
g
day
)
permitted
accordin
g
to the I
C
NIRP is 30 J
/
m². With a mean illu
-
minance o
f
500 lx
,
this dose is achieved with an e
ff
ec
-
tive UV radiation of a
pp
rox. 2 mW
/
klm. The IE
C
61167
data sheets
f
or metal halide lam
p
s indicate the maxi
-
mum values o
f
the
g
enerated e
ff
ective UV radiation.
IE
C
62035 states the limit values for
U
V radiation
(
2 mW
/
klm resp. 6 mW
/
klm
)
for hi
g
h-intensity dischar
g
e
lam
p
s as an indication
f
or the luminaire manu
f
acturer
.
Light
Non-visual path
• Cirkadian rhythm
• Alertness
• Tiredness
• Hormone production
• Vitality
•
Recovery
• Blood circulation
• Metabolism
•
Recognizing pictures
• Brightness, illuminance
• Contrast
• Shapes
• Movement
• Perception
• Information
Visual path