
45-6 Optical
45.2 Image Sensing
e primary functions occurring within a standard image sensor are the conversion of light photons
fa
lling
on
to
th
e
im
age
pl
ane
in
to
a co
rresponding
sp
atial
di
stribution
of el
ectric
ch
arge,
th
e
ac
cumula-
tion
an
d
sto
rage
of th
is
ch
arge
at th
e
po
int
of ge
neration,
th
e
tr
ansfer
or re
adout
of th
is
ch
arge,
an
d
th
e
co
nversion
of ch
arge
to a us
able
vo
ltage
sig
nal
. Ea
ch
of th
ese
fu
nctions
ca
n
be ac
complished
by a va
riety
of ap
proaches,
bu
t
on
ly
th
e
pr
incipal
se
nsor
ty
pes
wi
ll
be co
nsidered
he
re
. Se
nsors
ca
n
be di
vided
in
to
tw
o
gr
oups:
(1
)
va
cuum
tu
be
de
vices
in wh
ich
th
e
ch
arge
re
adout
is ac
complished
by an el
ectron
b