<s>
A	O
vector	B-General_Concept
monitor	I-General_Concept
,	O
vector	B-General_Concept
display	I-General_Concept
,	O
or	O
calligraphic	O
display	O
is	O
a	O
display	B-Device
device	I-Device
used	O
for	O
computer	O
graphics	O
up	O
through	O
the	O
1970s	O
.	O
</s>
<s>
It	O
is	O
a	O
type	O
of	O
CRT	B-Device
,	O
similar	O
to	O
that	O
of	O
an	O
early	O
oscilloscope	O
.	O
</s>
<s>
In	O
a	O
vector	B-General_Concept
display	I-General_Concept
,	O
the	O
image	O
is	O
composed	O
of	O
drawn	O
lines	O
rather	O
than	O
a	O
grid	O
of	O
glowing	O
pixels	B-Algorithm
as	O
in	O
raster	B-Algorithm
graphics	I-Algorithm
.	O
</s>
<s>
Some	O
refresh	O
vector	B-General_Concept
displays	I-General_Concept
use	O
a	O
normal	O
phosphor	O
that	O
fades	O
rapidly	O
and	O
needs	O
constant	O
refreshing	O
30-40	O
times	O
per	O
second	O
to	O
show	O
a	O
stable	O
image	O
.	O
</s>
<s>
These	O
displays	O
,	O
such	O
as	O
the	O
Imlac	B-Device
PDS-1	I-Device
,	O
require	O
some	O
local	O
refresh	O
memory	O
to	O
hold	O
the	O
vector	O
endpoint	O
data	O
.	O
</s>
<s>
Other	O
storage	B-General_Concept
tube	I-General_Concept
displays	O
,	O
such	O
as	O
the	O
popular	O
Tektronix	B-General_Concept
4010	I-General_Concept
,	O
use	O
a	O
special	O
phosphor	O
that	O
continues	O
glowing	O
for	O
many	O
minutes	O
.	O
</s>
<s>
In	O
the	O
1970s	O
,	O
both	O
types	O
of	O
vector	B-General_Concept
displays	I-General_Concept
were	O
much	O
more	O
affordable	O
than	O
bitmap	O
raster	B-Algorithm
graphics	I-Algorithm
displays	O
when	O
megapixel	O
computer	O
memory	O
was	O
still	O
very	O
expensive	O
.	O
</s>
<s>
Today	O
,	O
raster	O
displays	O
have	O
replaced	O
nearly	O
all	O
uses	O
of	O
vector	B-General_Concept
displays	I-General_Concept
.	O
</s>
<s>
Vector	B-General_Concept
displays	I-General_Concept
do	O
not	O
suffer	O
from	O
the	O
display	B-Algorithm
artifacts	I-Algorithm
of	O
aliasing	B-Error_Name
and	O
pixelation	B-Algorithm
—	O
especially	O
black	O
and	O
white	O
displays	O
;	O
color	B-Device
displays	I-Device
keep	O
some	O
artifacts	B-Algorithm
due	O
to	O
their	O
discrete	O
nature	O
—	O
but	O
they	O
are	O
limited	O
to	O
displaying	O
only	O
a	O
shape	O
's	O
outline	O
(	O
although	O
advanced	O
vector	O
systems	O
can	O
provide	O
a	O
limited	O
amount	O
of	O
shading	O
)	O
.	O
</s>
<s>
Refresh	O
vector	B-General_Concept
displays	I-General_Concept
are	O
limited	O
in	O
how	O
many	O
lines	O
or	O
how	O
much	O
text	O
can	O
be	O
shown	O
without	O
refresh	O
flicker	O
.	O
</s>
<s>
Vector	O
graphic	O
displays	O
were	O
first	O
used	O
in	O
1958	O
by	O
the	O
US	B-Device
SAGE	I-Device
air	I-Device
defense	I-Device
system	I-Device
.	O
</s>
<s>
In	O
1963	O
,	O
Ivan	O
Sutherland	O
at	O
MIT	O
first	O
used	O
a	O
vector	O
graphic	O
display	O
for	O
Sketchpad	B-Application
,	O
his	O
pioneering	O
CAD	B-Application
program	I-Application
.	O
</s>
<s>
In	O
1968	O
,	O
he	O
and	O
his	O
team	O
again	O
used	O
a	O
vector	B-General_Concept
monitor	I-General_Concept
to	O
display	O
wireframe	B-Algorithm
images	O
of	O
3D	O
models	O
.	O
</s>
<s>
This	O
time	O
the	O
display	O
was	O
head	B-General_Concept
mounted	I-General_Concept
.	O
</s>
<s>
The	O
obviously	O
heavy	O
system	O
was	O
held	O
up	O
by	O
a	O
support	O
arm	O
structure	O
called	O
The	B-Device
Sword	I-Device
of	I-Device
Damocles	I-Device
.	O
</s>
<s>
The	O
system	O
is	O
widely	O
considered	O
to	O
be	O
the	O
first	O
computer-based	O
virtual	B-Application
reality	I-Application
.	O
</s>
<s>
Notable	O
among	O
vector	B-General_Concept
displays	I-General_Concept
are	O
Tektronix	O
large-screen	O
computer	O
terminals	O
that	O
use	O
direct-view	O
storage	B-General_Concept
CRTs	I-General_Concept
.	O
</s>
<s>
(	O
The	O
CRT	B-Device
has	O
at	O
least	O
one	O
flood	B-General_Concept
gun	I-General_Concept
,	O
and	O
a	O
special	O
type	O
of	O
display	O
screen	O
,	O
more	O
complicated	O
in	O
principle	O
than	O
a	O
simple	O
phosphor	O
.	O
)	O
</s>
<s>
Vector	B-General_Concept
displays	I-General_Concept
were	O
used	O
for	O
head-up	B-Application
displays	I-Application
in	O
fighter	O
aircraft	O
because	O
of	O
the	O
brighter	O
displays	O
that	O
can	O
be	O
achieved	O
by	O
moving	O
the	O
electron	O
beam	O
more	O
slowly	O
across	O
the	O
phosphors	O
.	O
</s>
<s>
Vector	B-General_Concept
monitors	I-General_Concept
were	O
also	O
used	O
by	O
some	O
late-1970s	O
to	O
mid-1980s	O
arcade	O
games	O
such	O
as	O
Armor	B-Application
Attack	I-Application
,	O
Asteroids	B-Application
,	O
Omega	B-Application
Race	I-Application
,	O
Tempest	B-Application
,	O
and	O
Star	B-Application
Wars	I-Application
,	O
and	O
in	O
the	O
Vectrex	B-Operating_System
home	O
videogame	O
console	O
.	O
</s>
<s>
The	O
CRT	B-Device
had	O
an	O
internal	O
,	O
specially	O
contoured	O
,	O
very	O
fine	O
mesh	O
operating	O
at	O
low	O
potential	O
,	O
which	O
was	O
placed	O
after	O
the	O
deflection	O
plates	O
at	O
the	O
gun	O
exit	O
.	O
</s>
<s>
The	O
17KV	O
electrostatic	O
field	O
between	O
this	O
mesh	O
and	O
the	O
separate	O
,	O
conductive	O
coating	O
charged	O
to	O
final	O
accelerating	O
potential	O
inside	O
the	O
CRT	B-Device
funnel	O
,	O
accelerated	O
the	O
electron	O
beam	O
axially	O
as	O
well	O
as	O
radially	O
,	O
expanding	O
the	O
possible	O
image	O
size	O
to	O
cover	O
the	O
8x10	O
"	O
screen	O
of	O
the	O
17.75-inch	O
long	O
CRT	B-Device
.	O
</s>
<s>
Without	O
the	O
mesh	O
,	O
the	O
8x10-inch	O
CRT	B-Device
would	O
have	O
had	O
to	O
be	O
almost	O
three	O
times	O
as	O
long	O
.	O
</s>
<s>
Some	O
vector	B-General_Concept
monitors	I-General_Concept
are	O
capable	O
of	O
displaying	O
multiple	O
colors	O
,	O
using	O
either	O
a	O
typical	O
shadow	B-General_Concept
mask	I-General_Concept
RGB	O
CRT	B-Device
or	O
two	O
phosphor	O
layers	O
(	O
so-called	O
"	O
penetration	O
color	O
"	O
)	O
.	O
</s>
<s>
Atari	O
used	O
the	O
term	O
color	O
quadrascan	B-General_Concept
to	O
describe	O
the	O
shadow-mask	B-General_Concept
version	O
used	O
in	O
their	O
video	O
arcade	O
games	O
.	O
</s>
<s>
Some	O
monochrome	O
vector	B-General_Concept
displays	I-General_Concept
were	O
able	O
to	O
display	O
color	O
using	O
peripherals	O
such	O
as	O
the	O
Vectrex	B-Operating_System
3-D	O
Imager	O
.	O
</s>
