How Patents Work Today

Many people are confused about how patents work. First of all, one invention may require several patents. Inventions may be a combination of many smaller parts, all of which have to be invented. For example, a light bulb might have several patents–one for the filament, another for the way to carbonize the filament, yet another for the shape of the bulb.

Another patent might show the way to manufacture the bulbs. Of course, that bulb has to fit in a lamp, which gets electric power from a generator somewhere, which passes through wires. All of these parts had to be invented and patented. Also, every time an invention is improved, the inventor must apply for another patent as shown on

Also, remember that patents work differently than copyrights or trademarks. A writer can renew a copyright on his book, but most of the time an inventor cannot renew a patent. There are some exceptions, but not many. In Edison’s lifetime, patents lasted 17 years. Today they last 20 years from the time you file for a patent. Afterward, anyone can copy the patent.

Of course, an inventor could also receive a patent for making a major change or improvement on someone else’s invention. Edison received hundreds of patents for things he improved but did not originally invent: the telegraph, telephone, stock ticker and typewriter are just a few examples.

An invention must be “novel,” or unique, to receive a patent. That means inventions must not be described in printed publications before the patent is awarded. This happened to Edison in 1878 when he filed a patent application at the same time in Great Britain and the United States. The British patent was approved first (number 1644).

Unfortunately, the US Patent Office decided that this constituted prior publication and therefore rejected the US patent application. This had devastating consequences for Edison, because it included several important innovations to the phonograph, including the making of disc-shaped records.

Since the US rejected the patent, Edison’s American competitors were allowed to copy it. If Edison had won the US patent, there might still be an Edison recording company today.

Copies of all United States patents can be ordered from the United States Office of Patents and Trademarks. Learn more about patenting from

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