You can freely build on How Buried Channel CCDs Move Data Deep Inside Silicon Chips
This patent expired in 1993. Every claim — 0 independent, 1 dependent — is now unenforceable. Anyone can use, reproduce, manufacture, sell, or offer for sale this technology without a license.
Original assignee
Individual
Patent granted
1974
Expired
1993
Forward citations
22
What this patent covers
This patent describes a way to move electrical charges through the middle of a semiconductor material rather than along its surface. By creating a 'buried channel'—a specific potential energy path deep inside the silicon—the device prevents charges from getting trapped by surface defects, which were a major problem in early chip designs. The device uses a series of electrode plates on the surface to pull these charges along this internal path, essentially acting like a bucket brigade for electrons. This allows for much faster and more reliable movement of data within the chip.
What is now free to use
All 1 claims of US 3792322 are in the public domain. Specifically:
The 1 dependent claim 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 charge-coupled devices that store or transfer charge directly on the semiconductor surface.
Does not cover memory structures that rely on traditional floating-gate transistors for long-term storage.
Does not cover devices lacking the specific ohmic contact means required to bias the storage medium for internal depletion.
Who is building on this today
The technology was pioneered at Bell Labs by Willard Boyle and George Smith, who later won the Nobel Prize for this work. Today, major semiconductor manufacturers and sensor companies like Sony, Samsung, and ON Semiconductor continue to refine the underlying physics of charge transfer in CMOS and CCD image sensors.
Products built on expired version of this technology
Digital camera image sensors
Early digital video camcorders
High-speed analog signal delay lines
How to cite this patent in your documentation
Individual. US Patent 3792322. Buried channel charge coupled devices. Granted 1974, expired 1993. 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.