During descent; a B767 flight crew detects smoke billowing up from between the upper EICAS screen and the glare shield for approximately 5 seconds. An emergency is declared and an expeditious approach and landing are accomplished. No further problems are encountered.

Narrative

During arrival at 10;000 FT MSL; my First Officer asked me what [was] burning. A second or two later I smelled smoke also and the saw smoke billow up from between the upper EICAS screen and the glare shield for approximately 5 seconds. The smoke had an acrid odor and both crew members immediately donned O2 masks. We chose not to don smoke goggles because our eyes were not irritated. An emergency was declared with Approach and vectors to final were requested. In order to reach the runway as soon as possible; aircraft was flown at greater than 250 KTS below 10;000 FT. The smoke dissipated during this phase of flight and a normal landing was accomplished. ARFF was standing by and escorted aircraft back to the ramp after landing. After shutdown a Fireman came into the cockpit and checked the instrument panel with what looked like an IR detector and determined that there was no active fire. There were no indications of instrument failures during the arrival and after the initial smoke (which lasted about 5 seconds) there was no further active smoke entering the cockpit.