Welcome to the home page of the Thomas Edison Patent List. You can view all of Edison's 1,093 United States patents or you can find a patent using two different search engines. The first way is by typing a key word. The other way is by choosing from a list of categories. These are: the electric light system, phonograph, motion pictures or movies, alkaline battery, automobile, cement, design, lead-acid battery, manufacturing, ore mining, railroad, rubber, telegraph, telephone. We hope that this makes it easier to search for the patents you want.

Thomas Edison applied for his first patent, the electric vote recorder, on October 28, 1868 when he was 21. He was 84 when he filed his last patent, "Holder for Article to be Electroplated," in 1931. He died later that year. (The patent was granted two years later, in May 1933.) Edison also received patents from other countries such as the United Kingdom, France and Germany. These foreign patents are not listed here. Most of them duplicate the US patents but protected his work in those countries. Patents can protect any invention that is not common knowledge.

Most of Edison's patents were utility patents, but about a dozen of them are design patents. A utility patent can cover an invention or process that is mechanical, chemical or electrical in nature. Design patents cover ornamental designs and last only 14 years. Since they are a different kind of patent, they have their own numbering system. That is why their numbers are much lower than the utility patents. (There is a third kind of patent--plant patents--but these were not available in Edison's time.)

Each patent has three important dates. The date of execution is when the paperwork applying for a patent is completed and signed by the inventor. The date of application is the date the Patent Office receives the papers. The date of issue is when the Patent Office officially awards the inventor a patent for a new invention. All dates are given first by the year, then the month, then the date.

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.

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. Otherwise the inventor might lose the patent application. 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. Contact them at www.uspto.gov

This database was researched and organized by the Seton Hall Preparatory School Intern Staff of 1999. Each intern looked up dozens of original patents, placed them into the proper categories. and double checked all dates and numbers. These students were: Jerome Davis, Greg Kornegay, Robert Polizzano, Leo Selvaggio and Les Walter.