PatentBrief

Original data · The Public-Domain Index

387 landmark patents are now free to build on.

44% of the 885 patents PatentBrief explains have entered the public domain — their protection has lapsed, so anyone can use, manufacture, and build on the invention without a license. Below: the most-cited, ranked.

Methodology

Computed directly from the PatentBrief database. A patent counts as public domain when its status is expired or its term has run (US utility patents last ~20 years from filing). “Times cited” is the forward-citation count — the number of later patents that build on it — our proxy for influence. Every figure on this page is derived from the underlying records, not estimated.

Most influential inventions now in the public domain

Ranked by times cited
#PatentGrantedTimes cited
1Making Hybrid Antibodies from Different AnimalsGenentech Inc19898,214
2How to Make Many Copies of a Specific DNA SegmentCetus Corp19877,558
3How to Make Billions of Copies of a DNA SegmentCetus Corp19876,231
4How Scientists Create Human-Friendly Antibodies for MedicineProtein Design Labs Inc19964,274
5How a Multi-Touch Screen Detects Multiple Fingers and PalmsUniversity of Delaware20012,641
6How Doctors Implant a Permanent Stent Using a BalloonExpandable Grafts Partnership19882,425
7Boosting Anti-Infective Activity with Muramyldipeptides and LiposomesSyntex USA LLC19852,340
8How to Make Many Copies of a DNA Piece with HeatCetus Corp19902,132
9How Multi-Touch Screens Track Multiple Fingers at OnceApple Inc20101,995
10How to Encapsulate Active Materials in Lipid Bubbles EfficientlyIndividual19801,862
11How Canon's Bubble Jet Printers Make Ink DropletsCanon Inc19881,806
12How Amazon's One-Click Ordering Works for Online PurchasesAmazon com Inc19991,636
13Logitech's Method for Using Two Fingers on a TouchpadLogitech Inc19981,577
14How Two Special Antibodies Find Substances in Body FluidsHybritech Inc19831,572
15Making Strong, Porous PTFE: The Gore-Tex ProcessWL Gore and Associates Inc19761,364
16How the iPhone's Slide-to-Unlock Gesture WorksApple Inc20101,269
17How an Enzyme Helps Find Specific DNA in a SampleHoffmann La Roche Inc19931,183
18How to Redesign Mouse Antibodies for Safe Use in HumansGenentech Inc20001,161
19How Load Balancers Route Web Traffic Based on Specific ContentResonate Inc19981,148
20How 3D Printers Build Objects Layer by Layer from LiquidUVP Inc19861,094
21How to Make Pill Coatings That Keep Medicine Stable Over TimeEuro Celtique SA19971,092
22How Organic Diodes Make Light Using Special MoleculesEastman Kodak Co19821,031
23How RSA Public-Key Encryption Keeps Digital Messages SecretMassachusetts Institute of Technology19831,015
24Making High-Concentration Antibody Medicines Stable for InjectionGenentech Inc2001878
25How Phones Sense Your Finger Hovering Without Touching the ScreenApple Inc2010860

Public domain by decade granted

  • 1870s2
  • 1880s2
  • 1890s1
  • 1900s9
  • 1910s16
  • 1920s14
  • 1930s18
  • 1940s16
  • 1950s27
  • 1960s33
  • 1970s51
  • 1980s40
  • 1990s56
  • 2000s69
  • 2010s32
  • 2020s1

Leading fields now free to build on

  • consumer_electronics116
  • biotech69
  • mechanical50
  • telecommunications34
  • software23
  • semiconductors19
  • automotive14
  • materials13
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