Shipments of projection sets, which can have screens 50 inches or larger and range in price from $3,000 to $5,000, leaped more than 25 percent to almost 270,000 units.

Moreover, the digital projection set will probably cost thousands of dollars less than a flat-panel display.

Some projection sets will stretch a standard 4:3 picture to fit the screen, although this usually results in some picture distortion.

The tube-based sets offer brighter and crisper pictures than the projection sets, though projection-sets use screens as large as five feet.

Newer projection sets use high-quality screens that work well from most angles, but older sets may have a fairly narrow viewing area.

For even larger pictures, it is necessary to use projection sets.

Because it is a transmissive technology, L.C.D. can be used in both direct view and projection sets.

In the past, large image size was accompanied by diminished brightness so that projection sets (like traditional movies) had to be viewed in darkened rooms.

In particular, there has been a mini-boom in the sale of large-screen projection sets, because the large screen shows off the videodisk to the best advtange.

That's why an unusual number of projection sets are making their debut this fall.