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We're still waiting for the flat, hang-on-the-wall TV but maybe it has moved a little closer with the announcement of a new 14-inch flat-screen portable from Panasonic, due to go on sale in Japan this month



Ten years ago we suspect most technology pundits, including ourselves, would have confidently predicted that by the mid to late 1990's the cathode ray tube would be well on its way towards becoming a museum piece and we'd all be watching large flat-panel display TVs, hung on the living room wall.  Today no-one would make such a rash prophesy and it is clear the CRT will be with us for many years to come. Large flat-screen TVs are still a long way from the high-street, that's not to say they don't exist, indeed several manufacturers have succeeded in making flat screens over 20-inches across, but the processes involved are not sufficiently refined to make them a practical or economic proposition for mass production.



There are now at least a score of flat-screen technologies -- that we know about -- some will never make it out of the laboratory, others, like liquid crystal (LCD) are commonplace and used in applications as diverse as pocket TVs, camcorder viewfinders and portable computer displays. Along the way there have been several interesting diversions, including a particularly clever variant on the CRT theme developed by Clive Sinclair (as was), back in the early 1980's. For a while it looked as though LCD display screen would eventually grow large enough for living-room TV displays but it has been clear for some time that there are almost insurmountable production problems that will limit the size of displays intended for the domestic market to ten or so inches for the foreseeable future. The biggest one is the high failure rate. LCD screens are made up from tens of thousands of picture elements or pixels; a single faulty pixel near the centre of the screen is enough to render the display commercially useless. As screen sizes increase so too do the number of pixels, and the reject rate. Ironically LCD technology  has a very promising future in large-screen displays, as optical elements in projection TV systems and we can expect to see some interesting new products, aimed at the domestic market, over the next few months.


Other technologies hold out more promise and one in particular, the Beam-Matrix display, has enabled Panasonic, to produce a flat colour screen in commercial quantities measuring 14-inches across. Beam Matrix is a hybrid technology, combining the digitally-controlled switching systems of LCD type displays, with the light-emitting processes of a CRT. Inside the evacuated glass panel the faceplate or screen is coated with phosphor stripes, in much the same way as a normal  CRT. Behind the screen there is a matrix of electrodes which control the flow of electrons emitted by rows of fine horizontal filaments. These act like thousands of miniature electron guns, replacing the single high-power gun in a CRT. As the electrons pass through the matrix they are precisely guided on to the phosphor stripes by a set of electrostatically-controlled deflection plates. As the electrons strike the phosphor it emits lights, producing the picture.


Prototype Beam Matrix displays were shown as long ago as 1989, and at the time resolution was claimed to be in excess or 400 lines, or around two thirds that of a similarly-sized CRT. That compares with the 200 to 300-line resolution of the best LCDs. More importantly, Beam Matrix displays can show much finer graduations in colour and brightness, giving a noticeably sharper, brighter and more natural-looking picture, especially when compared with LCD, and nearly as good as a CRT. The other big advantage is a wider viewing angle, almost as good as a normal TV, with none of the colour distortion that occur when LCD screens are viewed from above or to one side.



That brings us more or less up to date with the Panasonic TH-14F1 'Flat Vision' set which is due to go on sale in Japan about now. It has a screen size of 38cm or 14-inches which gives a horizontal resolution of 442-lines, and 440-lines vertically. The set is less than 4-inches thick and it comes with a tilt stand and remote control. Working samples were shown at a recent consumer electronics exhibition in Germany and we can report that the picture looked very good indeed, almost indistinguishable from a CRT in fact.


Tempted? Well, there had to be a catch, actually there are several. This set will do nothing for your electricity bill, the power consumption is some 85 watts, that's more than some 26-inch stereo TVs and two or three times as much as many 14-inch colour portables. But surely the flat screen has made the set more portable? Not so, the TH-14F1 tips the scales at over 16 kg, that's several kilograms heavier than many 14-inch portables. It hardly goes without saying that flat screen TVs will be more expensive than CRT sets, but by how much? Twice, three times the price? Keep guessing. In Japan the projected selling price for the TH-14F1 will be around 228,000 yen or a little less than 2,000; that's more than ten times the price of a decent quality 14-inch colour portable from a high street multiple! Who knows, maybe in ten years the CRT really will be a thing of the past but somehow we doubt it...



R.Maybury 1993 0510




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