# How Douglas Engelbart Invented the Computer Mouse

> The 1970 patent for the X-Y position indicator, better known as the computer mouse, which allowed users to move a cursor across a screen for the first time.

- **Patent:** US 3541541
- **Original title:** X-y position indicator for a display system
- **Owner:** Stanford Research Institute
- **Granted:** 1970
- **Status:** Public domain (expired)
- **Times cited:** 162
- **Field:** consumer_electronics, mechanical

## What it does

The patent describes a device with two wheels positioned at a 90-degree angle to each other. As the user moves the device across a flat surface, the wheels rotate independently to track movement in the X and Y axes. This mechanical data is transmitted to a computer to move a cursor on a display screen. It replaced the need for complex keyboard commands to navigate graphical interfaces.

## What it does NOT cover

- Does not cover optical sensors, as this patent relies on physical wheels for tracking.
- Does not cover wireless connectivity, as the original design required a physical cord.
- Does not cover multi-button configurations, as the original patent focused on a single-button design.

## The clever bit

By using two perpendicular wheels, Engelbart translated physical hand movement into precise coordinate data, solving the problem of how to intuitively point at digital objects.

## Real-world examples

1. The original wooden prototype demonstrated at the 1968 Mother of All Demos
2. Early Xerox Alto workstations
3. Apple Lisa and Macintosh mouse peripherals

## Why it matters

This invention is the foundation of modern human-computer interaction. It enabled the shift from text-based command prompts to the graphical user interfaces that define how we use computers today.

## Frequently asked questions

### What does How Douglas Engelbart Invented the Computer Mouse cover?

The 1970 patent for the X-Y position indicator, better known as the computer mouse, which allowed users to move a cursor across a screen for the first time.

### Who owns patent US 3541541?

Stanford Research Institute owns this patent, granted in 1970.

### 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 3541541 cited by?

This patent has been cited by 162 later patents that build on its ideas.

### What problem does this patent solve?

This invention is the foundation of modern human-computer interaction. It enabled the shift from text-based command prompts to the graphical user interfaces that define how we use computers today.

### What does this patent NOT cover?

Does not cover optical sensors, as this patent relies on physical wheels for tracking.

**Full plain-English explainer:** https://patentbrief.org/patent/us/3541541/computer-mouse-input-device

**Original patent:** https://patents.google.com/patent/US3541541

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_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:

- [Early Device for Tracking Objects with a Pen](https://patentbrief.org/patent/us/3055113/etch-a-sketch) — This 1962 patent describes an early system for tracing the path of an object using a pen-like stylus that records its movement on a surface.
- [How a Handheld Thumb-Controlled Computer Mouse Works](https://patentbrief.org/patent/us/RE40324/playstation-dualshock-controller) — A handheld mouse designed to be held in the air, using the thumb to control a cursor while fingers rest in ergonomic channels.
- [How Early Hard Disk Drives Accessed Data Quickly](https://patentbrief.org/patent/us/3503060/hard-disk-drive) — A 1970 patent detailing a mechanical system for moving read-write heads across magnetic disks to retrieve stored information rapidly.
- [How the Apple Mac Dock Magnifies Icons](https://patentbrief.org/patent/us/7434177/itunes-digital-music-store) — Apple's 1999 patent on the macOS Dock, which shrinks a row of app icons to save screen space and smoothly magnifies them as your mouse pointer glides over them.
- [Logitech's Method for Using Two Fingers on a Touchpad](https://patentbrief.org/patent/us/5825352/apple-pinch-to-zoom) — Logitech's 1998 patent describes how a touchpad can detect two fingers touching it in a specific sequence to perform actions like clicking or dragging, going beyond single-finger mouse emulation.