Expired Patents

How to Make Billions of Copies of a DNA Segment

This patent describes the Polymerase Chain Reaction (PCR), a method to rapidly create many copies of a specific piece of DNA or RNA, enabling its detection and analysis.

How the iPhone's Slide-to-Unlock Gesture Works

Apple's 2010 patent describes unlocking a device by dragging a specific graphical image across the touchscreen along a predefined path, a gesture that became iconic with the original iPhone.

How Doctors Implant a Permanent Stent Using a Balloon

This patent describes the method for placing a permanent, expandable wire mesh tube inside a blood vessel or other body tube using a balloon-tipped catheter to widen it and keep it open.

How to Make Many Copies of a DNA Piece with Heat

This patent describes the Polymerase Chain Reaction (PCR) method, a technique to make millions of copies of a specific DNA segment using a heat-resistant enzyme and repeated temperature changes.

How to Encapsulate Active Materials in Lipid Bubbles Efficiently

This patent describes a method for trapping biologically active substances inside tiny, multi-layered fat bubbles called liposomes, using a specific water-in-oil emulsion and gel-forming process to improve how much material gets captured.

How RSA Public-Key Encryption Keeps Digital Messages Secret

This patent describes the foundational RSA algorithm, a method for securely sending messages where anyone can encrypt a message using a public key, but only the intended recipient can decrypt it using a secret private key.

How 3D Printers Build Objects Layer by Layer from Liquid

This patent describes the foundational method for 3D printing, where a machine builds a three-dimensional object layer by layer by hardening a liquid material with light or other energy.

How to Make Many Copies of a Specific DNA Segment

This patent describes the fundamental three-step process for making millions of copies of a specific piece of DNA using short starter molecules and an enzyme, a technique known as Polymerase Chain Reaction (PCR).

How Two Special Antibodies Find Substances in Body Fluids

This patent describes a "sandwich" method using two highly specific, man-made antibodies to detect and measure tiny amounts of specific substances, like disease markers, in a fluid sample.

Making Strong, Porous PTFE: The Gore-Tex Process

This patent describes a specific process for rapidly stretching a highly crystalline form of PTFE plastic to create a strong, porous material with a unique internal structure, forming the basis for products like Gore-Tex.

How Machines Build 3D Objects Layer by Layer from Melting Plastic

This patent describes a method and machine for creating three-dimensional objects by precisely depositing melted material, layer by layer, from a movable nozzle onto a base.

Prodigy's System for Interactive Online Information and Shopping

Prodigy's 1994 patent outlines an interactive online system that delivered news, shopping, and banking to personal computers by breaking applications into 'objects' stored locally or remotely, and used user data for targeted ads.

New Pyrimidine Chemical Compounds for Treating Tumors

This patent describes specific new chemical compounds, called N-phenyl-2-pyrimidine-amine derivatives, designed with precise molecular structures for potential use in treating cancer.

How Stores Make Custom Products On-Demand with Remote Approval

This patent describes a system where a store can make a custom product for a customer, but only after getting permission and the necessary design information from a central, remote office.

How Early Cell Phones Handled Calls Across Different Towers

This patent describes a system for early portable phones to automatically find the strongest signal from a base station and switch channels as the user moves, reducing battery drain and interference.

How to Make Human Erythropoietin (EPO) Using Engineered DNA

This patent describes the specific DNA sequences and methods to engineer cells to produce erythropoietin (EPO), a protein vital for red blood cell production, outside the human body.

How Special Sugars Make Medicines Dissolve Better

This patent describes how to make poorly water-soluble drugs dissolve and absorb better by mixing them with specially modified, non-crystalline sugar molecules called cyclodextrin derivatives.

How Websites Get Ranked by Importance

This patent describes a computer method for scoring documents in a linked database, like the internet, by considering the importance of other documents that link to them, helping search engines find better results.

How Lasers Correct Vision by Reshaping the Eye's Front Surface

This patent describes a method for precisely reshaping the front surface of the eye using an ultraviolet laser to correct vision problems like nearsightedness, farsightedness, and astigmatism.

How an Enzyme Helps Find Specific DNA in a Sample

This patent describes a method for detecting a specific DNA sequence in a sample by using a labeled DNA probe and an enzyme that cuts the probe, releasing detectable fragments.

How Amazon's One-Click Ordering Works for Online Purchases

Amazon's 1999 patent describes how a customer can buy an item online with just one click, bypassing a traditional shopping cart by using pre-stored payment and shipping information.

How a Modern Camera Sensor Captures Light and Converts It to Data

This patent describes a camera sensor technology that combines light-capturing elements with a special circuit to read out the image data quickly and efficiently, all on a single chip.

Making Hybrid Antibodies from Different Animals

This patent describes how to create new, engineered antibodies by combining parts of antibodies from two different animal species, then growing them in a lab.

How Multiple Computers Share a Network Cable Without Crashing

This patent describes how multiple computers can share a single communication cable by listening for other transmissions and stopping their own if a collision occurs, then trying again later.

Boosting Anti-Infective Activity with Muramyldipeptides and Liposomes

This patent describes a method to make anti-infective drugs called muramyldipeptides work better by injecting them separately but close in time with tiny fat bubbles called liposomes into an animal.

How Early CT Scans Created Detailed Body Images

This 1973 patent describes a method for using X-rays from many angles to build a detailed 2D image of the inside of a body, like a slice of a CT scan.

Displaying Friends' Activities in a Social Network Feed

This patent describes how social networks like Facebook collect what users do, create short updates about those actions, and show them to specific friends in a personalized list called a "news feed."

How Phones Sense Your Finger Hovering Without Touching the Screen

This patent describes a system for electronic devices, like phones, to detect a finger hovering just above the screen, display a specific interactive element below it, and then let you control that element with gestures without ever making contact.

How to Create a Secret Code Key Without Meeting First

This 1980 patent describes a way for two people to create a secret code key over a public channel, like the internet, without ever meeting or sharing the key directly.

Logitech's Method for Using Two Fingers on a Touchpad

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.

How Computers Compress Data Using Dictionary Building

This 1985 patent describes a method for making computer files smaller by building a dictionary of common data patterns and replacing them with shorter codes.

How Engineered Antibodies Target TGF-beta Proteins to Fight Cancer

This patent describes specific engineered antibodies, made from mouse and human parts, designed to block TGF-beta proteins to help treat various cancers like breast or lung cancer.

Sticky, Tiny Plastic Balls Made from Acrylates

This 1972 patent describes how to make tiny, sticky, and durable plastic balls (microspheres) using a specific mix of acrylate chemicals and a special water-based process.

CSIRO's High-Frequency Wireless Network Technology

This 1996 patent from CSIRO describes a wireless local area network system that can send data reliably using radio waves above 10 GHz, even when signals bounce off walls.

How Keurig's Original Single-Serve Coffee Pod System Works

This 1994 patent describes the original Keurig system for brewing single cups of coffee using a special filter pod that holds coffee grounds and separates them from the brewed liquid.

Weapon That Shoots Wires to Deliver Electric Shocks

This 1974 patent describes a weapon that fires projectiles carrying wires to deliver incapacitating electric shocks to a target from a distance.

How a Cholesterol-Lowering Drug Molecule Was Patented

This patent protects the specific chemical structure of a molecule designed to lower cholesterol, including its various salt forms and its use in medicine.

How a Multi-Touch Screen Detects Multiple Fingers and Palms

This patent describes the underlying electronic circuits and methods for a multi-touch surface that can track multiple fingers and palms simultaneously, even before they fully touch the screen.

Catheter System for Opening and Closing Body Passages

This 1980 patent describes a medical catheter system with a guide catheter and a special dilatation catheter that can expand to open or close body passages, like blood vessels.

Early Lithium-Ion Battery Design Using Chalcogenides

This 1977 patent describes an early rechargeable battery design using lithium as one electrode and titanium disulfide as the other, a key step towards modern lithium-ion technology.

How Scientists First Made DNA Replicate in New Cells

This 1980 patent describes a method for cutting and pasting DNA pieces in a lab to create new, self-replicating genetic material that can be inserted into bacteria, a foundational technique for genetic engineering.

Detecting Genetic Differences Using DNA Probes and Enzymes

This 1987 patent describes a method to find tiny differences in DNA sequences by using special DNA pieces (probes) and cutting enzymes, which can help diagnose genetic conditions like sickle cell anemia.

How Organic Diodes Make Light Using Special Molecules

Eastman Kodak's 1982 patent on creating light-emitting diodes (OLEDs) using organic materials, specifically a layer of porphyrinic compounds to help inject electrical charges.

Tiny Capsules for Electronic Paper Displays

MIT's 1999 patent on a special ink made of tiny capsules that can change color when an electric field is applied, forming the basis for early e-readers.

Preventing Protein Damage with Extra Methionine

This 1993 patent describes how adding extra methionine to protein-based medicines can prevent them from degrading, especially in liquid or semi-solid forms.

Mice Engineered to Develop Cancer for Research

Harvard's 1988 patent on genetically engineered mice that carry cancer-causing genes, designed to help scientists study how cancer develops and test treatments.

Using Nuclear Magnetic Resonance to Detect Cancer in Tissue

This 1974 patent describes a method and apparatus using nuclear magnetic resonance (NMR) to measure how quickly certain atomic nuclei in a tissue sample return to their normal energy state, helping to distinguish cancerous from healthy tissue.

How Canon's Bubble Jet Printers Make Ink Droplets

Canon's 1988 patent on bubble jet printing uses a tiny heater to instantly vaporize ink, creating a bubble that pushes out a droplet of ink from the printer head.