Polarizer Sheet for Standard 120-Hz-Capable Plasmas?

Numerous posts in these AVS sections point out why standard plasmas can't deliver 3D adequately. Part of consultant Andrew Wood's article, "3D Displays in the Home," in the July '09 Information Display covers these problems, too (phosphor decay time, two polarization states needed, only 60 Hz, etc.). (BTW, there are other online related pieces in this special Home Theater 3D Technology issue.) [EDIT: Online article access requires a free password signup, or SID.org membership]

Haven't read about anyone installing a polarizer plastic sheet in front of a 120-Hz-capable plasma. Opinions whether this might work with shutter-type 3D glasses (or passive?) and a 3D-capable computer with decoding software for sequential display? There's polarized sheeting online, 56" wide by 9' long; (lost the URL link). For photographic lighting, AIUI, and may not be top optical quality. And that length--way more than needed--is $500-$600. My 1080p 65" plasma (screen area only) is ~57.5" wide. If it worked, suppose you could make a roll-down screen panel or just use Velcro for occasional 3D viewing.

My Panasonic plasma (TH-65VX100U) handles 48--120 Hz vertical rates as a PC input, and has an external-scaler mode that disables video-processor settings. (That differs, of course, from 120-Hz display techniques that interpolate extra frames to 'smooth' motion images.) Suspect some 120-Hz-capable plasmas would require a down-scaled input, not 1920X1080 (!) But standard 1080i versus 720p sometimes appears very similar when the same cameras are used, as with the upcoming golf Masters tournament (ESPN/CBS). Polarizers would dim images, although this model's reported 60,000:1 contrast ratio might help. VX100s and other Panny models have non-standard wider-gamut color phosphors but suppose they wouldn't overcome ghosting due to decay times. Just musing here to exhaust possibilities. :-) -- John

The section in Woods article (cited) about why non-3D plasmas won't work:

While I suggested shutter-type glasses above for use with an add-on polarization sheet, Woods is talking about passive glasses, so that probably should be modified. Some discussion with 3-D Display FAQ author Ron last week for attempting 3D with my plasma dealt mostly with shutter-type glasses, as I recall. -- John

^^^Greetings, Lee. As mentioned, just exhausting any potential options that might permit 3D on my plasma--and perhaps other standard PDPs. -- John

Good ? [and Lee's query]. Sheets are clearly polarized in just one direction. Perhaps 3D tinkerers can see an option for switching left-right views with either shutter or passive glasses used with software switching. The Woods quote I excerpted above mentions PDPs have "unpolarized" outputs and the need for two polarized states. A polarized sheet provides two states. -- John

Thanks for the replies--and Lee's intriguing wII head-tracking video find. From the back-and forths with Ron last week in the Display section, I concluded 120 Hz capability is needed along with a sequential input for my non-3D plasma. The ghosting problem with too-slow phosphors is often mentioned. But still...assuming a PC is providing a 120 Hz sequential output, with correct shutter-glasses sync, it wasn't clear why my 120-Hz vertical-rate 2D plasma couldn't be used for 3D just as a computer display hooked to the 3D output with shutter glasses. So, as Woods indicates in his article quote, my query about adding an optical filter to provide two polarization states--although a sheet is permanent in one polarization plane. If bad ghosting from slow phosphor decay is the only reason 120-Hz plasmas can't be used with sequential PC outputs, that's good enough reason not to attempt it. -- John

Thanks. Appreciate the direct article link. My link accesses the whole special-3D issue, which, erroneously it seems, indicates a free password signup is needed for article access.

Yes, Woods point about adding an "optical filter" is vague. But if large sheets of filter material polarized as you describe are available, and software like the Stereoscopic Player can convert side-by-side (etc.) 3D encoding into line-by-line, maybe that would work. Also, Ken's link above to the RealD add-on screen filter Monitor-Z shows the filter added to a CRT display; not sure if they're made for large plasma displays or if the encode/decode would work on non-CGI material. Then there's always that phosphor decay-time issue. -- John

Yes, scanned that diagram while replying to Mike5. While that technique might apply to plasmas (my interest), noticed they diagrammed only an LCD panel. Perhaps circular polarization does work for both display types, although a scan of Xpol's pdf doesn't mention plasmas AFAIK. -- John

Mentioned in some earlier queries about 3D potential of my '09 Panasonic TH-65VX100U that I doubted its PC input could handle 1080p/120. But the spec page indicates it handles 48--120 Hz vertical rates as PC inputs. (Noticed in a recent post about 3D-specific PCs that their specs shave off ~15% from a full 1080p/120.) VX100s are pro/custom plasmas, but if the 1080p resolution was downscaled via a PC ~15% for a 120 Hz PC input, the opinion seems to be that ghosting from too-slow phosphors would still spoil images. Someone testing a 120-Hz-capable plasma might disprove this, but don't plan investing in a 3D PC until that happens. By "standard" in my title I only meant non-3D-specific plasmas. -- John

Page 52 (specifications) does list 48--120 Hz vertical scanning frequency as applicable PC signals.

Clearly it would require a suitable PC with the right software (frame sequential output, supposedly). As mentioned, suspect 1080p/120 would require resolution downscaling. I've been assuming the PC could supply an adequate sync signal for shutter glasses. My Panny plasma has a mode for an external scaler (disabling video processor settings)--although that might be unnecessary with a PC signal input. -- John

Noticed that the spec page for Viewsonic's VX2265wm FuHzion 120 Hz 3D-ready LCD monitor (22" wide) lists PC VGA up to 1680x1050^* non-interlaced as an input. Not sure if that requires using its Dual link (DVI-D) with (HDCP) digital input connector.

But ~1650X1050p is generally what I've guesstimated as a scale-down substitute for 1920X1080/120 Hz that I've always suspected requires too much bandwidth. So perhaps something between 1280X720p/120 Hz and 1650X1050/120 Hz would work. Panasonic offers an add-on SDI-input card for their VX100 plasma monitors (my 65" set) but not sure if it's dual link capable. Anyway, if someone succeeds in putting 120 Hz 3D on any pro plasma monitor, it's interesting to discover all the minutia involved. And, of course, have to mention conventional-plasma phosphor decay speeds--just to (hopefully) forestall the usual excessive-ghosting 3D squelch. -- John
^* On further thought, that's apparently the LCD pixel resolution, which wouldn't necessarily signify here.

So looks like I might need the VX100 add-on card, Dual Link HD-SDI Board or one of the other boards for Panny's monitors--with the right PC-output board. -- John