And this for a general explanation ~
"This is indeed pure marketing, they needed a large number - they've got
it. That this number does not mean anything - doesn't matter, nobody
cares. And indeed - we see that everyone is confused now.
Ok, here is how it works:
Plasma screen can indeed only have it's pixels on or off. There is no half-on or something like this.
So, how are different shades being generated?
The answer is simple - for every field, ANY plasma is using a number of
subfields. In earlier days e.g. 300 subfields, which made 5 subfields
per field (60Hz operation mode).
So, how is the 'luminance' being genearted out of those subfields?
This is done by differnt algorithms, every manufacturer is using their
own. Common thing between them is - it is using a modified
pulse-width-modulation. Modified, becaue a plasma cell can only be
activated once during the sequence of one field.
Assuming 600 Subfields and 100Hz feed, we have 6 Subfields per field.
So, what are valid subfield sequences for e.g. a green sub-pixel?
1-0-1-0-1-0 is not a valid sequence - since, as I mentioned, a cell can be only activated once.
0-0-1-1-1-0 is a valid sequence. Here the cell is activated once at a subfield #3 and is being de-activated at a subfiled #6
How exactly this activatinon/deactivation is being implemented with
every panel, e.g. in the middle of the subfiled sequence, at beginning
or dynamically, is intellectual property of manufacturers and is not
being disclosed.
There are a number of patents existing on this subject matter. The
sequence of the subfield activation is important for a level of
artifacts like False Contouring or flicker with plasma screens.
As such, number of subfields (e.g. 600) doesn't tell anything. The only
important thing is - how many subfields per field are being used.
For example 480 Subfields, but with a 60Hz refresh, is better (8
subfields per field) than 600 Subfields at 100Hz (only 6 subfields per
field).
So please just try to ignore those irritating numbers born in the
depths of the marketing department, they do not have anything to do
with how the picture or movement look like on the screen."