While LCD TV models now vastly outsell plasma TV sets for DTV and HDTV viewing in the home, technically speaking, plasma may offer better 3-D images due to its faster processing speed (refresh rate) and higher contrast ratio.
The eye perceives higher quality when there's a big visual difference between blacks and whites. This is the contrast ratio, and plasma technology generally provides a greater contrast ratio than LCD technology. Blacks are deeper on plasma screens than on LCD screens because LCDs use tiny crystals to block the light when creating black, which still allows traces of light to get through. Even if an LCD screen could go to all the way to black as well as a plasma screen, it can't do it as fast. Plasma screens can go to black 60 times faster than LCD, making it measurably better in this area.
One of the main differences between the two technologies, which has a definite impact on 3-D TV viewing, is processing speed. LCD technology has come a long way in increasing its refresh rate, with of 120Hz, 240Hz and even, some companies claim, 480Hz. However, plasma technology has never had an issue with motion blur.
Now, with increased marketing efforts of LCD manufacturers to remove the stigma of slow refresh rates by touting ever-higher rate figures, plasma technology manufacturers have addressed refresh rate times by measuring processing speed. They call it “subfield drive” or “subfield motion technology.” Major manufacturers with these specifications claim processing speeds of up to 600Hz.
LCD TVs have typically not been able to show 3-D content in full HDTV 1080p; estimates are about 600 lines of effective resolution capability for a 120Hz LCD HDTV and 700 to 800 lines of effective resolution for a 240Hz LCD TV. Plasma technology, on the other hand, has the speed to deliver the full 1080 lines of resolution to each eye.
Does this matter to the average TV viewer? Because 600 to 800 lines of resolution per eye is still a very high definition, this puts the argument more in the area of theory than what matters to viewers.
What may be a bigger differentiator between the two TV technologies is whether there is motion blur or panning issues with 3-D content on LCD 3-D TVs. Another advantage for plasma technology when dealing with 3-D content is depth perception, because the pixel structure of a plasma cell has always yielded slightly better depth of picture.
The plasma versus LCD battle is, of course, a fast-moving target. Both technologies are extremely capable and have improved dramatically in recent months, and will continue to get better with time.
However, it's generally agreed that plasma technology currently holds the quality edge over LCD for 3-D viewing. Plasmas have better color fidelity, faster refresh rates and improved black levels (although some of the most recent, high-end LCD TVs are up to par with some of the best plasma TVs when it comes to black levels).