- 7 -
Sustain Step 4
Fig. M
When sustain pulse is stopped, Ions and Electrons are
remained again as Wall voltage. However polarity of wall
voltage is reversed.
Sustain Step 5
Fig. N
Ions and Electrons which is generated by 2nd sustain dis-
charge are charged on the pixel wall (dielectric) around the
electrodes.
Repeat Step 1 to Step 5
Fig. O
To keep discharge continuously step 1 to 5 operation will be
repeated.
As the result sustain pulse is alternated. Therefore we call
this drive system AC Drive type.
If sustain operation is repeated longer, brightness level of the
pixel is increased. Therefore depend on sustain discharge
time brightness of pixel is controlled.
Sub-Field drive
Fig. P
Sub-Field drive is PDP unique system.
While one TV field period, 8 bits digital video signal compo-
nent is reproduced by 8 sub-fields operation.
Each Sub-Field’s address period are all same.(Consist of
one initialization and 480 scanning operation.)
But Sustain period of each Sub-Field are different.
1st Sub-Field (SF) reproduce only 1 step brightness.
2nd SF reproduce 2 steps brightness.
Each sub-field’s sustain period are increased gradually.
However total 256 brightness difference can be reproduced
on the screen.
+++
| | |
+++
| | |
+++
| | |
Vs
Sustain Cycle
AC Drive Type Plasma Display
Sustain Pulse
Address Period
8 Sub Fields
1 TV Field
1
2
4
8
16
32
64
128
=
1st 2nd 3nd 4th
5th
6th
7th
8th
Sustain Period
