On January 24, 1950, the original microwave oven patent was issued to Percy LeBaron Spencer under the title “Method of Treating Foodstuffs.”
The origins of the microwave oven can be traced to World War II. Scientists in Britain had developed the magnetron, a tube that produces microwaves, as part of a radar system to spot Nazi warplanes. The technology was passed to the United States, and Raytheon was among the companies putting it to use for the military. In early 1945, the Raytheon Company was looking for something to sell to civilians after World War II was over. The company’s head, Laurence Marshall, convened a team of technicians to come up with an answer.
One of these technicians, Percy Spencer, suggested that Raytheon should build on its radar expertise by making an oven. He had walked by a microwave tube one day and noticed that a candy bar in his pocket had melted. Intrigued, he placed some popcorn kernels near the tube and watched them pop all over his lab. The next morning, he exploded an egg for a colleague.
Spencer was apparently a whiz with vacuum tubes. With Marshall’s blessing, Spencer and the Raytheon staff started working on ovens. On October 8, 1945 Raytheon filed a U.S. patent for Spencer’s microwave cooking process, and a prototype was developed for testing. It was almost six feet tall, weighed 670 pounds, and sold for the equivalent of $20,000 in today’s dollars. It was marketed to restaurants and called the Radarange, the winning name in an employee contest.
Raytheon engineers continued to refine the product so that it could be marketed to consumers. They acquired Amana in 1965, making use of that company’s expertise with kitchen products. Two years later, the first countertop domestic oven was introduced. It was a 115-volt microwave oven, cooked hamburgers in 35 seconds, and cost around $3100 in today’s dollars.
By 1975, sales of microwave ovens would, for the first time, exceed that of gas ranges. Today, more than 95 percent of American households own a microwave oven, and 75 percent of those surveyed by a recent Yankelovich Monitor study ranked the microwave oven as “almost impossible/pretty difficult” to do without. Only the automobile ranks higher.
Spencer, although never graduating from grammar school, became Senior Vice President and a member of the Board of Directors at Raytheon, receiving 150 patents during his career. Because of his accomplishments, Spencer was awarded the Distinguished Service Medal by the U.S. Navy and has a building named after him at Raytheon.