HD2402
- 38 -
V1.4
6.4.7
Table j.k.l.
780-1400
Table
j.k.l. 780-1400
shows L
R
exposure limit for parameters “
j
”, “
k
”, “
l
”.
The limit varies according to source observation time and to angular dimensions; con-
sequently, different exposure limits correspond to different observation times and di-
mensions. In particular:
L
R
= 6.6
•
10
6
/C
α
[W m
-2
sr
-1
]
for t > 10s (j limit)
L
R
= 5
•
10
7
/(t
0.25
C
α
) [W m
-2
sr
-1
] for 10
μ
s
≤
t
≤
10s (k limit)
L
R
= 8.89
•
10
8
/C
α
[W m
-2
sr
-1
]
for t < 10
μ
s (l limit)
C
α
is a coefficient that depends from source
α
dimensions; its value is:
C
α
= 11
for
α
≤
11mrad
C
α
=
α
for
11
≤
α
≤
100mrad
C
α
= 100 for
α
> 100mrad
The displayed values are:
•
Irradiance value E
r
[W/m
2
] (corresponds to the instant value if a single sample
is considered, or to the mean value if several samples are considered).
•
Alpha angle in degrees, it is the angle under which the analyzed source is seen.
•
Alpha angle in radiants, equal to the previous angle, but expressed in radiants.
•
Omega solid angle in steradians, a solid angle under which the analyzed source
is seen. This angle is used for the calculation of luminance.
This parameter is estimated based on the radiance value and not on that of irradi-
ance, so the more detailed are the entered geometric parameters, the more plentiful
will be the data on limit value.
All possible cases are analyzed in the following.
•
Geometric data not available
:
o
L
r
(100mrad) [W/(m² sr)] radiance calculated assuming that all the light comes
from a circular area whose angular dimension is 100mrad. This value is to be
compared with the three limit values.
o
t_
lim100
[s] exposure limit time, that is the time period during which a source can
be observed without damages to the visual system. This value is calculated with
the following procedure (all radiance values are expressed in [W m
-2
sr
-1
]):
Summary of Contents for HD2402
Page 2: ...HD2402 2 V1 4 HD2402 Photo Radiometer A O R Dosimeter...
Page 55: ......
