Flat is beautiful

Press, 17 December 1985, Page 32

Flat is beautiful

I believe in flat screens. In colour. At least 52cm across. Both for telly and • for computer use. They must come one day soon, and when they do they will , create as big a revolution as colour did when it came in and, swept the black and white television era to oblivion.

Screens and keyboards are a considerable way behind modern technology. Television manufacturers are now all flat out in a mad race to bring us a flat screen in colour. Understand, I am not talking here about liquid crystal display screens. Nor am I talking about plasma screens. I am talking about technology which will give us the same resolution, or better, as the current cathode ray tube, but will have a thickness — front to back — of less than 30cm. A screen that can be hung on th? wall or built into a computer without being overly obtrusive. At the moment the betting is the technology that will win this race will still be the cathode ray tube — heavily modified. It has

many attractions. Its technology is a known quantity. It fits in easily with all known systems. The scanning of the electrons across the face of the tube results in a picture built up of horizontal lines which can possibly be pushed to three times the definition of current standards with no problems. But most modern screens have their images fired at them by three electron guns — each with a separate

colour — which are grouped together and aimed at the screen. The electron is fired and accelerates towards the screen, hitting it and expending its energy as a dot of red, green or blue light. (If anyone ever tries to bluff you by talking about RGB monitors it is comforting to know the initials stand for, yes, red, green and blue). There is a limit to the closeness that these electron guns can be brought to the screen and still reach the picture edges. The limit at the moment seems to be about 110 degrees and this is the figure most manufacturers are working with. ' Sir Clive Sinclair, the redhaired scientific — but not financial — genius, showed one way of solving the problem by bending the stream of electrons to the face of the tube with a magnet so that the guns could be positioned at the side of the

screen. He has done this with success in his truly portable Sinclair television, but that is in black and white and slips into your pocket. Not quite what I had in mind.

If you bend the beams they need to be of a fairly low energy content and this tends to diminish the brilliance of the picture. Philips, the Dutch electronics company, is working on a snazzy scheme of separating the electrons into two streams — the picture forming scanning electrons from the highly energetic light producing electrons. Having achieved separation they then place a single gun behind the screen but very close and parallel to it and pointing downwards. The picture forming electrons come out of the gun and bounce off a deflecting plate at the bottom of the screen. They are turned 180 degrees through a lens and as they come back up the face of the screen they are bounced off a series of slats on to the screen face which gives almost precisely the same raster effect as the scanning of a normal cathode ray tube gun. But these are low energy electrons which need a bit of a boost to make the screen shine.

To do this, a cunning device known as an electron multiplier is used. This attracts the electrons to a series of metal plates which multiply the electrons and send them back again. All this may sound as if I am grossing out on high tech but the end result is Philips has already demonstrated a 30cm screen which is only 75mm thick. For colour, Philips is thinking of staying with one gun working at three times the normal speed and effectively filtering the signals once they hit the metal plates. Philips has not announced when it expects to have a full-scale working colour model — it is still working

on the 50mm prototype stage — but do not hold your breath.

Over in the land of the rising export markets, the electronics giant Matsushita is approaching the problem from another direction. • It has divided the screen up into what are, in effect, 3000 tiny cathode ray tubes. This means the deflection is minute and the guns are positioned very close to the screen. But this is not, by a country kilometre, a cheap solution. Sharp and Hitachi have taken another course, but won’t talk about it. But the word in Tokyo is that they will both be launching a flat-screen TV in the near future. When I was at the Tukuba Expo earlier this year I saw a flat screen only about 100 mm deep in operation, in full and glorious colour being driven by a video player. As far as I could tell it was made, by Toshiba. When I tried to inspect it I was shooed away in a most unceremonious fashion. My guess is that the Japanese already have most of the technology in place for producing flat screens in colour at a reasonable price. And we will be seeing them soon. Gareth Powell