The ubiquitous 40- and 60-watt incandescent light bulbs are supposed to be in their last few years of existence; a phase-out of incandescents mandated by the federal government begins next year with the 100-watt model and works its way down to the smaller bulbs in 2014.

Osram Sylvania

Bulb manufacturers are working on a variety of replacements, including halogens, which, like incandescents, make light by letting current flow through a filament. Others will be replaced by compact fluorescents.

But in August, Osram Sylvania will introduce another lamp it hopes will take a share of the market, using light-emitting diodes, or LEDs.

LED lamps are already showing up in Christmas decorations, flashlights, traffic signals and the occasional street lamp. Another marketing target is the thousands of freezer cases and refrigerator cabinets at supermarkets and convenience stores. The ones with glass fronts keep the lights on even when the doors are closed. Most use fluorescents, and every watt they consume becomes heat that must be removed by the cooling system. A lower-wattage LED would mean less work for the whole system.

Some LED’s have been produced as downlights for use in recessed ceiling fixtures. Osram Sylvania’s entry mimics the bulb shape of the standard incandescent, at least in its upper half; the lower half is a series of arches meant to dissipate heat.

The device (which the lighting industry calls a lamp, not a bulb) uses 12 watts, 80 percent less electricity than the standard 60-watt incandescent, and emits nearly as much light. (Watts are a unit of power; light is measured in lumens.) It’s supposed to last 25,000 hours, which is about three years of continuous use, or about 11 years if used for six hours a day.

The company has not announced the price, but LED’s meant to replace 40-watt bulbs are expected to be in the $20 range.

Rick Leaman, the chief executive of Osram Sylvania, would like some help selling them. He said the company had surveyed its customers and determined that, two years after Congress voted for the coming phase-out, 74 percent of the public is oblivious to it.

“We haven’t moved the needle in awareness,’’ Mr. Leaman said. And when lamps start to disappear from store shelves, “there will be a big backlash,’’ he said.

He suggested that the government should wage a publicity campaign. Otherwise, he predicted, the reaction will be, “Why are you taking my incandescent?”