The Ultimate Television Technology
With the Christmas markets approaching, this is the time of year when the producers of electronic gadgets set their final line-up of the year. That also makes it a good time to settle back and take stock of where technology has taken us to. Less than two years ago, people were saying that it is pointless to think about FullHD (1920x1080) resolution video because neither the display panels nor the media existed at that specification. In just a few months that changed and the technology journalists were taken by surprise. Both LCD and Plasma panels achieved the 1080p standard with gliding ease and it turned out that HD-DVD and Blu-Ray had been set to work at that level all along. It is safe to assume that Sony, Samsung, Toshiba and the other leading TV manufacturers knew what was around the corner, but with the pace of development so fast they must keep the next innovation under wraps. If the consumers knew that such improvements were just around the corner they would hold off their purchase indefinitely waiting for the next big thing. The same story was repeated with the introduction of 100Hz and 24p support, the rise of ever higher contrast ratios, wider colour gamuts and 10bit panels. What can we expect next?
The good news is that the rumour mill for new features has run dry. Now seems to be a safe time to buy without the threat of seeing our purchase become obsolete within months. Next year will be a different story but before we come to that let us look at the feature list for today's ultimate TV. When buying plasma we really only need to look for three things: 1080p resolution, high contrast ratios and direct 24p support. Here is our list of plasma TVs that reach the standard. It is only in the last few months that the significance of Blu-Ray's 24p feature for films has become apparent so what is it all about?
Since the dawn of the film industry, essentially all movies have been recorded at 24 frames per second. You might argue that with the pace of the action in some of today's films (think King Kong, Pirates of the Caribbean, Transformers), this frame rate is woefully inadequate and it is high time to update this number, but the fact is that the Hollywood studios show no sign of doing things better any time soon. TV broadcasts set a slightly different standard for frame rates. 50Hz in Europe and 60Hz in the US. In Europe when we watch a film on TV we see a video image that has been slightly sped up from 24 frames per second to 25 and then doubled to 50Hz. Once the sound has been pitch corrected, this 2% increase in pace is not really noticeable. In the US the conversion has always been more problematical. To reach 60Hz they must show one film frame three times and the next frame twice. This is called 3:2 pulldown. There is no change in pace but the uneven frame distribution makes for jerky motion which is just not so nice. With the US market in mind, the standard for recording films on Blu-ray discs was set to a native 24 fps rate. Given a suitable player and a suitable TV this makes it possible to view the movie in its original form. The marketing term for this feature is "direct 24p" but so far only a few TVs have it. Direct 24p means taking the video signal at 24 fps and displaying it without any uneven pulldown. In practice 5:5 pulldown is usually used to display at a 120Hz refresh rate. Beware, some TVs accept the 24p signal but use 3:2 pulldown to show it at 60Hz which amounts to a backward step for European viewers. The Blu-ray players do not have a feature to speed up the disk play rate to 25 fps so to maintain quality we really need that direct 24p feature.
For overall picture quality, plasma is acknowledged as superior to LCD. If you want the ultimate screen irrespective of cost then plasma is still the way to go. But plasma has some operational drawbacks: high power consumption and the danger of burn-in remain a concern. More significantly, if you don't have room for a 50inch plus screen, your choice of plasma at 1080p is limited to a handful of 42inch Panasonics. Certainly, the TH-42PZ70 is highly recommended, and if you can wait, the TH-42PZ750 will be one step better. If you can afford the cost and the space, the real ultimate is Pioneer's Kuro range.
In case your budget and your living room is of a more modest proportion but you still desire the best, LCD makes more sense. To overcome the technology's shortcomings, the top LCD makers have developed an array of electronics which bring them close to plasma standards for picture quality. LCD response times have stabilized around 8ms and unless they are hiding another surprise breakthrough this will remain a limiting factor. To compensate, 100Hz LCD TVs interpolate intermediate picture frames to give us less blurring on fast panning motion. How much this really helps is debatable, but in any case, the spec for the ultimate LCD must include it. Static contrast ratios for LCDs are also inferior to their plasma competitors but varying the backlight intensity gives a higher dynamic contrast ratio that works perfectly well except for scenes where there is detail in both light and dark areas at the same time. Finally the range of colours on LCD has in the past been more limited than plasma. The high end ranges from the best LCD makers now include wide colour gamut backlights or other colour enhancement technologies that bring them up to a similar standard. The picture processing must have at least 10bit colour depth to avoid colour banding on images with areas of slowly varying colour. Demanding these features plus direct 24p support, here is ZettaVolt's list of ultimate LCD displays to choose from. It now includes offerings from all the major LCD makers (except LG who seem to have been caught out by direct 24p). Special mention goes to Samsung's LE-46F86BD, Toshiba's 47Z3030DB and Sony's KDL-46X3500. These are truly excellent bits of kit if you are buying this year.
So what does the future hold? Plasma is probably near the limit of its capabilities. Production of smaller FullHD plasmas is not likely to be economically viable. It has been demonstrated at the trade shows that LCD panels can be made much thinner than current models. With plasmas that would be too difficult to achieve. Plasmas are heading for niche status then, but for LCD there is more hope. The most recent advance has been the introduction of LED backlights with local dimming for LCD panels. Currently this is only available for a handful of larger screens such as Sony's KDL-70X3500 and Samsung's LE-52F96BD. The LED backlight provides a better colour range and with local dimming, the contrast ratios may beat plasma in all but the most extreme cases. Next year we should expect to see a much wider range of models with LED backlights because it is clear that this technology has the potential to offer significant improvements over the current panels with fluorescent backlights. But will that actually happen? Perhaps, but perhaps not.
The cost of investment in display panel research and production is massive and the biggest producers are feeling the pinch. Turning a profit has proven an elusive goal across the industry and if they are to do so, they need to stabilize on what they have now for a while. For this reason we may see only limited application of LED backlight technology. Instead the leaders may want to leapfrog ahead to the next emerging technology which will surpass everything available at present. There are already several candidates for that place, with SED and OLED screens the leading candidates. They are said to be five years away because the advance is so great. But if they were in reality just one or two years away would they want to let on? As a taster, Canon have been quietly demonstrating SED screen to insiders this summer and Sony have announced that they will release an 11 inch OLED display in Japan before this Xmas. They may not want to tempt us any more until the Christmas shopping season is safely out of the way, but the Consumer Electronics Show in January may be interesting.