You can freely build on How Organic Diodes Make Light Using Special Molecules
This patent expired in 2000. 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
Eastman Kodak Co
Patent granted
1982
Expired
2000
Forward citations
1,031
What this patent covers
This patent describes how to build a light-emitting device, like a tiny light bulb, using organic materials. It details an 'electroluminescent cell' with a light-producing layer sandwiched between two electrical contacts (an anode and a cathode). The key innovation is adding a special 'hole-injecting zone' made of a porphyrinic compound, like phthalocyanine, right next to the anode. This layer helps electrical 'holes' (think of them as positive charges) move more easily into the light-emitting layer, making the device work better.
What is now free to use
All 0 claims of US 4356429 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.
Electroluminescent cells that do not use organic materials for the light-emitting zone.
Devices where the hole-injecting zone is not made of a porphyrinic compound.
Cells that lack a distinct hole-injecting zone between the luminescent zone and the anode.
Electroluminescent cells where the binder material has a breakdown field strength below 10^5 volt/cm.
Who is building on this today
The foundational work in this patent has been built upon by countless companies in the display and lighting industries. Major players like Samsung Display, LG Display, and Universal Display Corporation (UDC) are heavily involved in developing and manufacturing OLED technology, leveraging advancements in organic materials and device architecture.
Products built on expired version of this technology
Modern OLED displays in smartphones
OLED televisions
Flexible OLED screens
How to cite this patent in your documentation
Eastman Kodak Co. US Patent 4356429. Organic electroluminescent cell. Granted 1982, expired 2000. 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.