SANTA ROSA, Calif.  When Congress passed a new energy law two years ago, obituaries were written for the incandescent light bulb. The law set tough efficiency standards, due to take effect in 2012, that no traditional incandescent bulb on the market could meet, and a century-old technology that helped create the modern world seemed to be doomed.

But as it turns out, the obituaries were premature.

Researchers across the country have been racing to breathe new life into Thomas Edison’s light bulb, a pursuit that accelerated with the new legislation. Amid that footrace, one company is already marketing limited quantities of incandescent bulbs that meet the 2012 standard, and researchers are promising a wave of innovative products in the next few years.

Indeed, the incandescent bulb is turning into a case study of the way government mandates can spur innovation.

“There’s a massive misperception that incandescents are going away quickly,” said Chris Calwell, a researcher with Ecos Consulting who studies the bulb market. “There have been more incandescent innovations in the last three years than in the last two decades.”