Automatic Headlight Dimmers : Jacob Rabinow

Automatic Headlight Dimmers
ca. 1952

On a nighttime car trip in 1949 from Cleveland to Washington, Rabinow came up with a solution to one of modern life's little irritations: the need for continual manual adjustment to the brightness of headlights. He patented 16 variations on his Automatic Headlight Dimmer. The main feature distinguishing his patents from patents on automatic dimmers by other inventors was the scanning system. This system prevented a photomultiplier behind it in the dimmer from integrating ambient light. It responded only to bright spots. A refinement on the original patent enabled the dimmer to distinguish the alternating current of bright street-lights from the direct current of bright automobile headlights. Although Rabinow's automatic dimmer was clearly superior to the few types then in use by car companies, no company was willing to purchase the rights to produce it. It would have cost them an extra dollar in materials because of its scanning system.

Rabinow thought the dimmer was one of his best inventions but that it came 15 years too early. If he had invented it in the 1970s when automobile safety became a crusade, it probably would have proved successful for him. At that time, patents only lasted 17 years.