3 COMPOSITION AND CONSTRUCTION
3-6
EM210F-1
3.5 RAY
DIAGRAMS
3.5.1 Illumination
System
1
s
t c
onde
ns
e
r
le
n
s
2
nd c
o
n
d
e
n
s
e
r l
ens
Aper
tu
re
C
o
n
d
e
n
se
r m
in
ile
n
s
(C
M l
e
n
s
)
O
b
je
ctive
le
n
s
Pr
e-
fi
el
d
S
p
e
cim
e
n
Po
st-
fie
ld
T
E
M
m
ode
ED
S
m
ode
N
B
D
m
ode
CBD
m
ode
a
1 >
a
2
a
1
a
2
T
E
M
m
ode:
W
ide ar
e illum
inati
on m
ode.
For T
E
M
obser
vation
.
ED
S m
ode:
H
ig
h
cur
rent densit
y m
icr
o-
ar
ea illum
ination m
o
d
e
. For m
icr
o-
ar
ea dif
fraction m
o
de.
N
B
D
m
ode:
Sm
all conver
g
ence
ang
le m
icr
o-
ar
ea illu
m
inati
on
m
ode.
For m
icr
o-
ar
ea dif
fractio
n m
ode.
CBD
m
ode:
W
ide rang
e cha
n
g
e
able co
nver
g
ence a
n
g
le m
icr
o-
ar
ea illu
m
in
a
tio
n
m
ode.
For conver
g
ent
electr
on b
eam
dif
frac
tion.
M
ode
Pr
ob
e di
a.
TE
M l
o
w
ma
gs
.
TE
M h
igh
ma
gs
.
S
A
d
if
f.
C
B
D
d
if
f.
HD d
if
f.
TE
M
○
△
ED
S
NB
D
CBD
×
△
○
○
○
△
△
△
×
×
○
○
△
△
○
△
△
△
2.
4 to
0.
5
n
m
5 to
2 n
m
Fig 3.6 Ray diagram (Illumination system)
