Wide-screen movies were the rage of the '50s. And now wide-screen television is about to become the hot screen format for the '90. Make that late-'90s if you live in the United States.

The current issue of Video Magazine notes that Europeans will be able to buy wide-screen television sets beginning this month and that Sony is about to introduce an $18,000 Trinitron wide screen in the Japanese market. The Sony set will also be able to receive the new High Definition TV signal now being broadcast one hour a day in Japan.The European wide screens will range in price from $6,000 to $7,000 and will be sold by Thomson Consumer Electronics, the Paris-based worldwide television manufacturer whose American brands are RCA and GE.

The new TVs look different even before you turn them on. The boxy 4:3 ratio of current television tubes is replaced by a superwide tube with an aspect of 16:9. The Thomson set measures 34 inches in "viewable diagonal."

The new TV will be able to work with a number of broadcast systems and formats, including the current European standards - PAL and

SECAM - and a new, superior satellite-delivered TV system now being tested in Europe called MAC for multiplexed analog components.

In addition, France and Germany are scheduled to start broadcasts of a Wide-MAC format in 1991, which will have the same 16:9 format of the Thomson tube. Also, the set will be able to receive HDTV broadcasts when high definition becomes a fact of life on Europe's airways a little later in the decade.

But owners of the new set won't have to wait to use the wide screen TV's bells and whistles. When receiving existing standard broadcasts, or playing back videotapes or laserdiscs, the new set can double the number of horizontal lines - from Europe's standard 625 to 1,250 - resulting in an improved definition TV (IDTV) picture.

When will there be an American version? Thomson executives are non-commital, only saying "when there is a demand for it."

That, according to the experts at Video Magazine, is not any time soon.