Edison's First Practical Electric Light Bulb
Thomas Edison's 1880 patent for an electric lamp described the first commercially viable incandescent light bulb, using a high-resistance carbonized filament in a vacuum.
Original patent title: “Electric lamp”
What this patent covers
The actual claim
This patent describes an electric lamp designed to produce light by heating a thin, high-resistance material, called a filament, until it glows. The key innovation was using a carbonized fibrous or textile material, like a cotton thread, as the filament. This filament was sealed inside a glass bulb from which most of the air had been removed to create a vacuum. This vacuum prevented the filament from quickly burning out, allowing the bulb to glow for many hours and making it practical for widespread use.
What this patent does NOT cover
The boundaries
- Does not cover electric lamps that produce light without heating a filament until it glows, such as fluorescent lamps or LED lights.
- Does not cover light bulbs using different filament materials like tungsten, which became common much later.
- Does not cover arc lamps, which produce light from an electric arc between two electrodes.
- Does not cover non-electric lighting methods, such as gas lamps or oil lamps.
- Does not cover the systems for generating or distributing electricity to power the lamp.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The true innovation was finding a filament material that had high electrical resistance and could last for many hours when placed in a vacuum. Edison's use of a carbonized cotton thread, combined with a highly evacuated glass bulb, solved the problem of previous bulbs burning out too quickly, making electric lighting practical and economical for the first time.
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Early incandescent light bulbs for homes and businesses
Street lighting in the late 19th and early 20th centuries
Historical lighting fixtures
Decorative incandescent bulbs
Why it matters
The bigger picture
This patent is a cornerstone in the history of technology, representing the first commercially practical and long-lasting incandescent light bulb. Its invention dramatically changed daily life, enabling longer work hours, safer indoor environments, and the eventual widespread electrification of homes and cities. It laid the foundation for the modern electrical grid and the entire lighting industry.
Filed
November 4, 1879
Granted
January 27, 1880
Claim 1 — Plain English
What this patent covers
This patent describes an electric lamp designed to produce light by heating a thin, high-resistance material, called a filament, until it glows. The key innovation was using a carbonized fibrous or textile material, like a cotton thread, as the filament. This filament was sealed inside a glass bulb from which most of the air had been removed to create a vacuum. This vacuum prevented the filament from quickly burning out, allowing the bulb to glow for many hours and making it practical for widespread use.
The clever bit
The true innovation was finding a filament material that had high electrical resistance and could last for many hours when placed in a vacuum. Edison's use of a carbonized cotton thread, combined with a highly evacuated glass bulb, solved the problem of previous bulbs burning out too quickly, making electric lighting practical and economical for the first time.
What it does not cover
- Does not cover electric lamps that produce light without heating a filament until it glows, such as fluorescent lamps or LED lights.
- Does not cover light bulbs using different filament materials like tungsten, which became common much later.
- Does not cover arc lamps, which produce light from an electric arc between two electrodes.
- Does not cover non-electric lighting methods, such as gas lamps or oil lamps.
- Does not cover the systems for generating or distributing electricity to power the lamp.
Patent Journey
From filing to expiry
Patent Filed
1879
Patent Granted
1880
Patent Expired
1899
PatentBrief Score
Impact Score
Early stage
Citation count
29/40
Moderately cited
Claim breadth
0/20
Narrow claims
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assignee
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Citations
Patent lineage
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