# How Nichia Created the First Practical Blue LED Electrodes > A foundational patent describing the specific metal contacts needed to make gallium nitride LEDs efficient and commercially viable. - **Patent:** US 5563422 - **Original title:** Gallium nitride-based III-V group compound semiconductor device and method of producing the same - **Owner:** Nichia Chemical Industries Ltd - **Granted:** 1996 - **Status:** Public domain (expired) - **Times cited:** 251 - **Field:** semiconductors, consumer_electronics, energy ## What it does This patent details the construction of a light-emitting diode (LED) using gallium nitride, specifically focusing on how to create reliable electrical connections. It describes a 'second electrode' made of nickel or a nickel-gold alloy that sits on top of the p-type semiconductor layer. To ensure this connection works properly, the patent specifies that the electrode must be annealed—heated to at least 400 degrees Celsius—to form an ohmic contact, which allows electricity to flow easily into the semiconductor. This was critical because, without this specific metal-to-semiconductor interface, the device would not efficiently inject the current required to produce light. ## What it does NOT cover - Does not cover the underlying growth process of the gallium nitride crystal itself. - Does not cover LEDs made from materials other than gallium nitride-based III-V compounds. - Does not cover electrode materials that do not utilize nickel or nickel-gold combinations as specified. - Does not cover non-ohmic contact methods that rely on different electrical physics. ## The clever bit The innovation was realizing that a thin, light-transmitting nickel-based layer, when properly annealed, could provide the necessary electrical conductivity without blocking the light generated by the semiconductor underneath. ## Real-world examples 1. Early high-brightness blue LED indicators 2. White LED backlighting for LCD screens 3. General-purpose LED light bulbs ## Why it matters This patent was a key piece of the puzzle in the invention of the blue LED, an achievement that earned Shuji Nakamura and his colleagues global recognition. By solving the problem of creating stable electrical contacts for gallium nitride, Nichia enabled the mass production of blue, green, and eventually white LEDs. This technology fundamentally changed the lighting industry, transitioning the world from inefficient incandescent and fluorescent bulbs to energy-efficient solid-state lighting. ## Frequently asked questions ### What does How Nichia Created the First Practical Blue LED Electrodes cover? A foundational patent describing the specific metal contacts needed to make gallium nitride LEDs efficient and commercially viable. ### Who owns patent US 5563422? Nichia Chemical Industries Ltd owns this patent, granted in 1996. ### When does this patent expire? This patent has expired and is now in the public domain — anyone can use the invention freely. ### What is patent US 5563422 cited by? This patent has been cited by 251 later patents that build on its ideas. ### What problem does this patent solve? This patent was a key piece of the puzzle in the invention of the blue LED, an achievement that earned Shuji Nakamura and his colleagues global recognition. By solving the problem of creating stable electrical contacts for gallium nitride, Nichia enabled the mass production of blue, green, and eventually white LEDs. This technology fundamentally changed the lighting industry, transitioning the world from inefficient incandescent and fluorescent bulbs to energy-efficient solid-state lighting. ### What does this patent NOT cover? Does not cover the underlying growth process of the gallium nitride crystal itself. **Full plain-English explainer:** https://patentbrief.org/patent/us/5563422/blue-led-gallium-nitride **Original patent:** https://patents.google.com/patent/US5563422 --- _Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._ ## Related patents Semantically similar inventions in the PatentBrief corpus: - [How Organic Diodes Make Light Using Special Molecules](https://patentbrief.org/patent/us/4356429/oled-organic-light-emitting-diode) — 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. - [The Invention of the Transistor](https://patentbrief.org/patent/us/2524035/point-contact-transistor) — Bell Labs' 1950 patent for the point-contact transistor, the fundamental electronic component that makes all modern computing possible. - [How the First Infrared LED Was Invented](https://patentbrief.org/patent/us/3293513/infrared-led-biard-pittman) — Texas Instruments' 1962 patent for the first practical semiconductor diode that emits infrared light when electricity passes through it. - [How Amorphous Silicon Changed Solar Power](https://patentbrief.org/patent/us/4064521/semiconductor-device-having-a-body-of-amorphous-silicon) — This 1976 patent describes using a specific form of non-crystalline silicon to create cheap, thin semiconductor devices like solar cells. - [How Robert Noyce Invented the Modern Integrated Circuit](https://patentbrief.org/patent/us/2981877/noyce-planar-integrated-circuit) — Robert Noyce's 1959 patent for a semiconductor device that uses evaporated metal leads to connect components directly on a single silicon chip.