Media File: 1981
Sinclair in the News

The Economist
February 21, 1981

Slip it into your pocket

How about a really portable television set - no bigger than a paperback book - for less than £50 (perhaps only $100 for lucky Americans)? That is the aim of Mr Clive Sinclair, the British inventor/entrepreneur who has already pioneered, among other miniaturised electronic products, a television set a quarter the size of ordinary portables. The new Sinclair television (complete with built-in radio) would be about half the price and a third the size of its predecessor.

On Wednesday, Mr Sinclair revealed manufacturing plans for this project. The ingenious design involves a flat cathode-ray tube (revealed in The Economist, August 11, 1979) and has taken five years and £1m ($2.3m) to develop. Half the research money was provided by Whitehall's own venture-capital bank, the National Research Development Corporation. Sinclair Research Ltd of Cambridge, which subcontracts all of its manufacturing, has signed up Timex to make its new black-and-white television set. The American mass-producer of watches will manufacture the Sinclair television at its Dundee factory. Half the £5m investment cost (to be spread over four years) will, in fact, be provided by Scotland's economic planning department and its regional development office. The rest will come out of Sinclair Research's profits from its best-selling ZX80 personal computer.

All the world's leading television manufacturers are working on fancy new flat-screen designs. Most, however, are concentrating on advanced display techniques - like liquid crystals, thin-film transistors and so-called electro-luminescent panels. Most are still stuck in the laboratory. Reason: the conventional cathode-ray tube has become so good and so cheap.

The Sinclair concept makes it even cheaper. The idea for a flat cathode-ray tube was first mooted by Professor Denis Gabor of Imperial College, London, the inventor of holography and an early pioneer of the electron microscope. A normal cathode-ray tube has electrons fired from the back. The Sinclair design has the electron gun firing its beam in from the side instead. Inside the set, the electron beam is then bent through a right angle by an electrostatic field so as to strike a phosphor-coated screen mounted on the inside of the set's back plate. The viewer thus sees the picture, not darkly through the thick phosphor screen (as in a conventional set), but directly through a clear glass window in the front of the set.

Not having to look at a piece of thick phosphor-coated glass makes the picture appear much brighter. So less power is needed - in fact, about five times less than in a conventional set. And that means longer battery life.

Snags? Only one to talk about. The design is a compromise between simplicity and optical accuracy. The small screen size allows the set's electronics to fudge the picture somewhat. Circles, for instance, would appear slightly elliptical if they were not corrected (like human astigmatism) by a barrel-shaped lens on the set's faceplate.

This unfortunately restricts the angle of view slightly. It also limits the size the screen can be stretched to. The present design has a three-inch screen (measured across a diagonal) and the maximum is probably no more than nine inches or so. Britain's ministry of defence has been trying to get Sinclair Research to see how far it can push its flat-screen technology. It would like to use the rugged little device for displaying information to pilots of military aircraft.

There is, however, a clever dodge. Because of its inherent brightness, the Sinclair tube can be used to project a picture across a room, instead of merely displaying it internally. Equipped with a proper lens system, it could produce accurate pictures on a screen measuring perhaps three feet by four feet. And in colour, too. A projection model would not need to be so tiny and could therefore have three electron guns (one each for the red, green and blue colours), instead of the single gun used in the pocket-sized monochrome set.

Another colour trick being discussed is to use one of the super-fast liquid-crystal materials developed by scientists at the Royal Signals and Radar Establishment at Malvern, England. These can be switched many times faster than ordinary liquid-crystal materials. Used in conjunction with a Polaroid filter (like those in sun-glasses), they could produce a "synthetic colour" picture cheaply from a single gun instead of three.

All that, however, is three or four years away. Even the pocket-sized black-and-white set will not be on the market for another year. Timex, which has a reputation for cheap production costs, has still to engineer and install the automated assembly lines for the flat cathode-ray tube. The initial £1.25m production phase will provide enough capacity to produce 1m tubes a year. One major American retail chain is believed already to be negotiating an order for over 300,000 units for delivery in the first year.