Flat panel TV: today in the hand, tomorrow on the wall

Television small enough to fit in the palm of a hand or long and flat enough to hang on a wall like a painting. All this is beginning to arrive with a new wave of ''flat panel'' display technologies.

Today some word processors, computers, and other electronic goods carry the skinny panels. But wall screens are still costly and hard to produce. They remain a few years away.

Meanwhile, many consumers can see some of the new display technologies in an array of pocket-sized TV sets. The Sony Watchman, a black-and-white TV with a two-inch diagonal screen, hit the market first. It's about the size of a walkie-talkie but carries a larger-scale price ($350).

Next year, Sinclair Research Ltd of Britain is expected to unveil a TV set about the size of sardine can and priced as low as, perhaps, $100. The Casio Computer Company, a Japanese firm, is planning to sell a tiny flat-screen television for about $200 next spring. At least three other Japanese firms also are working on Lilliputian sets. These include a Dick Tracy-style wrist TV with a 1.2-inch screen.

The first television sets were made with screens as small as two inches. But the new tiny TVs are the first to use flat screens.

Laboratories around the world are studying at least a dozen flat-panel technologies. Thin panels promise sharper pictures as well as versatility. Also wall screens, eventually, could bring cinemalike entertainment into the home. Another advantage of thin panels is that many can operate off of small power sources such as penlight or watch batteries.

Thin-panel designers have found it difficult to reduce the distance between the electron gun, which shoots a picture-painting electron beam from the back of the tube, and the phosphor screen in the front. In the Watchman, Sony has mounted the electron gun below the screen. It fires electrons in at an angle. The firm now is working on a flat wall TV using the same technology, as well as a pocket color TV set. Both are believed a couple years away.

The next wave of pocket televisions will probably use screens made of liquid crystal - the material used in some digital watches. Toshiba, Hitachi, and Sieko have all been working with this technology, which relies on reflected rather than emitted light.

These systems may yield a family of television sets less than half the size of the hand-held Watchman. Liquid crystal now is used in some word processor and instrument displays. Other flat screen technologies are finding use in bank teller terminals and military devices.

Industry analysts estimate flat-screen technologies probably won't make serious inroads in the $2-billion-a-year world CRT market until the end of the decade.

''At least for the next 10 years, we don't see flat panels threatening the conventional TV market,'' said Dr. Mahbub Alam, an analyst with Arthur D. Little Inc., the consulting firm. ''However, it may provide a new independent market.'' Fuel stinginess

Big automakers are driving toward the elusive goal of a 100-mile-per-gallon car. Britain's state-run BL (British Leyland) has just built an experimental five-seater that gets 63 mpg under normal driving conditions. At a steady 30 mph , the mileage tops 133 mpg. Plastic and aluminum panels make the car about one-third lighter than the company's standard models. Mass production of the vehicle, though, is several years off. Robot role

US robotics sales should grow an average of 28 percent a year over the next decade, says Arthur D. Little Inc. The consulting company predicts that sales will jump from the current $200 million a year to $2.1 billion by 1992. One roadblock is concern among many workers about job displacement. But, the company says, robots are gaining acceptance among many workers who do ''dirty'' tasks such as spray painting and explosives handling. Water woes

US farmers could save $300 million annually by using more energy-efficient irrigation techniques, according to Battelle Pacific Northwest Laboratories. By adopting new equipment and conservation practices, the research group says, farmers could shave irrigation pumping costs by 35 percent a year. Two-thirds of the savings could be achieved by simply reducing the pressure of sprinkler systems and controlling water scheduling more tightly.