# How Thomas Edison Invented the Practical Incandescent Light Bulb

> Thomas Edison's 1880 patent for a carbon-filament electric lamp that made indoor lighting reliable and commercially viable for the first time.

- **Patent:** US 223898
- **Original title:** Electric lamp
- **Owner:** Individual
- **Granted:** 1880
- **Status:** Public domain (expired)
- **Times cited:** 28
- **Field:** energy, mechanical

## What it does

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 it does NOT cover

- 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.

## The clever bit

The innovation was the use of a high-resistance carbon filament in a near-perfect vacuum, which allowed the bulb to operate efficiently on a parallel electrical circuit rather than the high-voltage series circuits used by earlier, less practical designs.

## Real-world examples

1. Early incandescent light bulbs
2. Carbon-filament lamps used in 19th-century homes and factories

## Why it matters

This patent marks the transition from gas lighting to the modern era of electricity. It provided the core component for the first widespread, safe, and long-lasting indoor lighting system, effectively launching the global electric utility industry.

## Frequently asked questions

### What does How Thomas Edison Invented the Practical Incandescent Light Bulb cover?

Thomas Edison's 1880 patent for a carbon-filament electric lamp that made indoor lighting reliable and commercially viable for the first time.

### Who owns patent US 223898?

Individual owns this patent, granted in 1880.

### When does this patent expire?

This patent has expired and is now in the public domain — anyone can use the invention freely.

### What is patent US 223898 cited by?

This patent has been cited by 28 later patents that build on its ideas.

### What problem does this patent solve?

This patent marks the transition from gas lighting to the modern era of electricity. It provided the core component for the first widespread, safe, and long-lasting indoor lighting system, effectively launching the global electric utility industry.

### What does this patent NOT cover?

Does not cover the invention of the electric arc lamp, which relies on a different physical principle.

**Full plain-English explainer:** https://patentbrief.org/patent/us/223898/edison-incandescent-lamp

**Original patent:** https://patents.google.com/patent/US223898

---

_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._


## Related patents

Semantically similar inventions in the PatentBrief corpus:

- [How William Coolidge Invented the Modern X-Ray Tube](https://patentbrief.org/patent/us/1203495/coolidge-x-ray-tube) — A 1916 patent by William Coolidge for a high-vacuum X-ray tube that used a heated tungsten filament to control electron flow, replacing older, unreliable gas-filled tubes.
- [Nikola Tesla's Early System for Electric Lighting](https://patentbrief.org/patent/us/454622/tesla-coil-electric-lighting) — A 19th-century patent by Nikola Tesla describing an early method for distributing and regulating electric light using high-frequency alternating current.
- [How Georges Claude Invented the Neon Light](https://patentbrief.org/patent/us/1125476/neon-lighting-claude) — A 1915 patent describing the use of neon gas in sealed glass tubes to create bright, colorful light for signs and illumination.
- [Henry Seely's 1882 Electric Flatiron](https://patentbrief.org/patent/us/259054/electric-iron-seely) — An 1882 patent for the first electric flatiron, which used internal heating elements to replace the heavy, fire-heated irons of the Victorian era.
- [How Thomas Edison Improved Early Phonograph Recording](https://patentbrief.org/patent/us/200521/phonograph-edison) — An 1878 patent by Thomas Edison detailing mechanical improvements to early sound recording devices to make them more reliable.