Famous Patents That Have Expired

Every patent eventually expires and when important ones do, the technology they protected becomes available to anyone. Many inventions we now take for granted as open standards or widely available products were once exclusively controlled through patents. Here are some notable ones.

The Wright Brothers' airplane patents

The Wright Brothers received US Patent 821,393 in 1906, covering their method of controlling a flying machine using wing warping. The patent became the center of years of litigation that many historians believe slowed the development of American aviation.

The US military, frustrated by the patent disputes during World War I, essentially pressured a cross-licensing arrangement among manufacturers. The patent expired in 1923, by which point the aviation industry had moved on to different control mechanisms anyway. The Wright patent is often cited as an early example of broad foundational patents creating industry bottlenecks.

Alexander Graham Bell's telephone patent

Bell's original telephone patent (US 174,465, granted 1876) is one of the most famous in history, covering a method of transmitting vocal sounds telegraphically. It expired in 1893.

The expiration immediately triggered competition. Within a few years, hundreds of telephone companies formed across the country. The period immediately after expiration saw more growth in telephone access than in the entire preceding 17 years of AT&T's patent monopoly.

The Selden automobile patent

George Selden held a broad patent on the gasoline automobile (US 549,160, granted 1895) that he had strategically delayed granting for 16 years by filing continuation amendments. He licensed it to a cartel of manufacturers who used it to collect royalties from virtually every US automaker.

Henry Ford challenged and eventually won a ruling in 1911 narrowing the patent's scope so dramatically that it became unenforceable for most automobiles. The patent expired in 1912. Ford's victory essentially opened the US auto industry.

Aspirin

Bayer held patents on aspirin (acetylsalicylic acid) in several countries, but the US patent situation was complicated. After World War I, Bayer's US assets and trademarks were seized. The compound itself wasn't long-patentable and aspirin became generic decades ago.

The aspirin case is frequently cited when discussing pharmaceutical genericization, as the word "aspirin" itself became generic in the US through trademark loss, even though in many other countries it remains a Bayer trademark.

The JPEG image format

Multiple patents covered components of the JPEG compression standard. Forgent Networks famously claimed it held an enforceable patent (US 4,698,672) covering a key aspect of JPEG compression and spent years collecting licensing fees from technology companies.

The patent expired in 2006 and subsequent litigation over the claims failed. The JPEG format had been used for over a decade in billions of images before the dispute was fully resolved.

Tetracycline antibiotics

The tetracycline class of antibiotics was heavily patented by Pfizer and others in the 1950s. As those patents expired through the 1970s and 1980s, generic tetracyclines became widely available and inexpensive.

This pattern of pharma patents on foundational antibiotic classes expiring and enabling genericization has played out across most major antibiotic categories developed in the mid-20th century.

The GIF format

The GIF image format used a compression algorithm (LZW) covered by patents held by Unisys and IBM. Unisys began enforcing these patents in the 1990s, causing significant friction in the early web community. The patents expired in the early 2000s, resolving years of controversy.

The controversy also accelerated development of the PNG format as a patent-unencumbered alternative, which is now far more widely used than GIF except for animations.

What expiration actually changed

In each of these cases, the expiration of key patents had real consequences: new competitors, lower prices, faster adoption, or resolution of industry-wide disputes.

Patent expiration is not a bureaucratic footnote. For significant patents, it's a milestone with concrete market implications.

Checking whether a patent covering a technology you care about has expired is straightforward with the Patent Sunset calculator. Enter the patent number and get the calculated expiration date based on current USPTO data.