The standardised 7-inch (178 mm) round
sealed beam headlamp was introduced in 1940, and was soon required for all vehicles sold in the
United States. Britain, Australia and other
Commonwealth countries, as well as Japan, also made extensive use of 7-inch sealed beams. With some exceptions from
Volvo and
Saab, this headlamp size format was never widely accepted in continental Europe, leading to different front-end designs for each side of the Atlantic for decades.
The first
halogen lamp for vehicle headlamp use, the
H1, was introduced in 1962 by a European consortium of bulb and headlamp makers. Shortly thereafter, headlamps using the new light source were introduced. These were prohibited in the U.S., where
sealed beam headlamps were required. In 1978, sealed beam headlamps with internal halogen burners became available for use in the United States. Halogen sealed beams now dominate the sealed beam market, though it is considerably smaller than it was before replaceable-bulb composite headlamps returned to the U.S. in 1983.