You can freely build on How Thomas Edison Invented the Practical Incandescent Light Bulb
This patent expired in 1899. Every claim — 0 independent, 0 dependent — is now unenforceable. Anyone can use, reproduce, manufacture, sell, or offer for sale this technology without a license.
Original assignee
Individual
Patent granted
1880
Expired
1899
Forward citations
28
What this patent covers
The patent describes an electric lamp using a high-resistance carbon filament enclosed in a vacuum-sealed glass bulb. By using a carbonized thread or strip of paper as the filament, Edison achieved a stable light source that could burn for hundreds of hours. The vacuum prevents the filament from burning up instantly upon contact with oxygen, allowing it to glow brightly when electricity passes through it.
What is now free to use
All 0 claims of US 223898 are in the public domain. Specifically:
The 0 dependent claims add narrowing limitations and are also free.
What is NOT covered
Patent expiry frees this specific invention. Separately-patented improvements made after expiry may still be protected.
Does not cover the invention of the electric arc lamp, which relies on a different physical principle.
Does not cover modern LED or fluorescent lighting technologies.
Does not cover the electrical grid or power distribution systems required to power the lamp.
Who is building on this today
General Electric, founded by Edison, became the primary steward of this technology for decades. Today, the lighting industry has transitioned to LED manufacturers like Signify and Cree, which build on the fundamental concept of controlled electrical illumination.
Products built on expired version of this technology
Early incandescent light bulbs
Carbon-filament lamps used in 19th-century homes and factories
How to cite this patent in your documentation
Individual. US Patent 223898. Electric lamp. Granted 1880, expired 1899. Now in the public domain.
Note: This is a convenience citation. Consult a patent attorney for formal freedom-to-operate analysis.
PatentBrief is an educational resource and does not provide legal advice. Patent expiration information is derived from USPTO records and may not reflect continuation patents, divisional filings, or separately-patented improvements. For commercial use or production decisions, obtain a formal freedom-to-operate (FTO) opinion from a registered patent attorney.