You can freely build on How Douglas Engelbart Invented the Computer Mouse
This patent expired in 1987. 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
Stanford Research Institute
Patent granted
1970
Expired
1987
Forward citations
162
What this patent covers
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 is now free to use
All 0 claims of US 3541541 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 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.
Who is building on this today
Companies like Logitech and Razer have built entire businesses refining the form factor and sensor technology originating from this mechanical concept. While the original patent has long expired, the fundamental principle of relative motion tracking remains a core input method.
Products built on expired version of this technology
The original wooden prototype demonstrated at the 1968 Mother of All Demos
Early Xerox Alto workstations
Apple Lisa and Macintosh mouse peripherals
How to cite this patent in your documentation
Stanford Research Institute. US Patent 3541541. X-y position indicator for a display system. Granted 1970, expired 1987. 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.