Plasma Sub-field Drive

According to this explanation of plasma sub-field drive, it would seem to be possible for plasma manufacturers to create displays that could eliminate 3:2 pulldown judder altogether. A 192hz display rate (96hz per eye per second) with the Panasonic (or Samsung) plasmas would seem within the realm of possibility for the first generation products. Is it harder than it sounds like it should be, and if so, why?

From the link:

"A Plasma panel display has near instantaneous response times on the order of 0.002 milliseconds. What this implies is that a plasma TV subpixel is only alight for a fraction of a second. Typically, most conventional Plasma TVs display video at 60fps (research has shown that the human eye cannot tell any significant difference in motion and smoothness of videos at higher frame rates). This implies that each frame has to be displayed for 1/60 or 0.017ms. However, the sub pixels of a plasma TV stay alight only for around 0.002ms when excited. Thus, to display a single frame for 1/60 seconds, the plasma panel excites the sub-pixels in pulses so as to keep all the pixels bright so that they can continuously display the desired frame.

Thus, for example, a 60Hz plasma panel can have 10 pulses per frame, to display the image. Effectively, the screen is being refreshed 60Hz times 10 pulses/frame which gives us a value of 600Hz. This is what Plasma manufacturers refer to as the Sub field drive refresh rate. If the Plasma panel performs 8 pulses per frame, it gives a sub field drive refresh rate of 480Hz. Now when the displayed frame has to be changed to the next frame, the ultra-fast response times of the Plasma TV sub pixels enables an almost instantaneous transition to the next frame."

One of the things many of us have been questioning the last few days is whether the Panasonic is actually displaying 96hz per eye (192hz total). I'm wondering if it's doing this, but something odd about the sub-field drive is causing flicker at this rate. Just trying to fill in the holes in understanding of how plasma works.

I'll also ask here if anyone has seen a review of the Samsung plasma displays - including discussions of ghosting, black level, etc. Several stores in my area have the displays, but not a one is hooked up to a 3D Blu-ray player.

So, you're suggesting that 120hz is as fast as plasma can update new data to the individual pixels until manufacturing processes are improved? All that would be required for judder-free films in 3D would be 144hz - 3:3 pulldown and no judder. Unless that introduces flicker issues somehow. I admit that the pictures of the Panasonic display's 3D menus in another thread have me confused, since they seem to indicate that the display does 192hz (96hz per eye).

Thanks, Mike. I'm going to have to read that section a few times to get a handle on it. I wish it weren't in doctoral-speak. I'm sure to be thorough he had to use those terms, and he was addressing other scientists with the thesis, but the jargon gets in the way of my basic understanding of how the technology works.

If I were sitting down with such a scientist, I'd ask him to explain how the color of any one pixel of a single video frame is produced by its separate red, green and blue sub-pixels. That is, how are the red, green and blue dots of light switched on, at what intensity (all on, all off or something in between), and how fast? If I had a basic, clear understanding of what happened to create a single pixel of a single frame, I'd understand the whole image. It's probably all in the thesis, but it feels like I need a degree in electronic engineering to understand it.

OK, that clears it up for me. I've long read that plasma is a digital display technology, but never how the individual sub-pixels were employed to produce the exact amount of red, green and blue needed for a specific digital color.

Thanks, Mike. That was a very simple explanation, and really helpful. But, watch out. Next I might ask you to explain how LCD sub-pixels do what they do.

I should have known those basic things about how plasma and LCD work, but I didn't. You're my go to guy for concise, easily understandable definitions, Mike. I've read many times that LCD is an analog technology, while plasma is digital. Now I know precisely why.