Technology and Invention is a series by Rogers Corporation about the innovation, pioneering spirit, and transformative technologies that are creating a cleaner, safer, more connected world. Part 1: Historical Milestones, Part 2: The Plastics Revolution.

The Birth of Electronics

The word “electron” was first proposed by Johnstone Stoney in 1891 when he realized that an electric charge had a natural unit which could not be subdivided any further. Shortly thereafter, a series of experiments by J.J. Thomson led to the discovery of a light particle that carried a charge; the name “electron” was applied to it. The many applications of electrons moving in a near-vacuum or inside semiconductors were later dubbed “electronics.”

magnet-electron-shellThe electron itself has turned out to be a bit different than what J.J. Thomson originally described. Albert Einstein and others showed that electrons aren’t either particles or waves, but in some conditions act like particles and in others like waves. In fact, J.J. Thomson’s grandson, G.P. Thomson, received a Nobel Prize for his work on the wave character of electrons. We now know that electrons are part of a whole family of related particles — all of them infinitesimal points carrying charge, mass, and spin.

Printed Circuit Boards

PCBs are a combination of mechanical and electrical connections etched from copper sheets and laminated onto a non-conductive substrate. The first printed circuit boards (PCBs) can be traced back to the need to eliminate complex wiring and provided consistent results. In 1903, a German inventor, Albert Hanson, described flat foil conductors laminated to an insulating board, in multiple layers. In 1904, Thomas Edison experimented with chemical methods of plating conductors onto linen paper. In 1925, Charles Ducas submitted a patent that involved creating an electrical path directly on an insulated surface.

The commercial development of PCBs began in the 1940’s, post-WWII. After years of discussions with lithograph companies, Dr. Paul Eisler began making the first real operational printed circuit boards in Austria. Eisler found no demand for his product until the Americans started work on the proximity fuse to bring down V1 rockets; printed circuits were a critical component. Following the end of the war, the USA released the secret of printed circuits, then all electronics in airborne instruments were printed.

DrPaulEislerIn 1966, Rogers purchased technology from Westinghouse Electric Corporation that, although never used commercially, led to the development of flexible circuits for computers, telecommunications, and other electronics applications.

Also in 1966, Rogers established its first plant outside of Connecticut, in Chandler, Arizona, closer to where the electronics industry was growing rapidly. The new Circuit Systems Division began operations in a 40,000 square foot plant manufacturing flexible circuits, busbars, and the Mini/Bus, designed to distribute voltage to integrated circuits on printed circuit boards. The Microwave Materials Division spun off from the Circuit Systems Division and is now known as Advanced Connectivity Solutions.

Today, as circuit speeds continue to escalate and wireless communications proliferate, the need for high frequency circuit boards becomes paramount. Rogers’ high performance dielectrics, laminates and prepregs offer high frequency performance and low cost circuit fabrication for a wide range of electronic products, from adaptive cruise control to airborne antenna systems to network gear.

The Critical Role of Power Electronics

Power electronics technology converts and controls electrical power using high-efficiency switching mode electronic devices. The technology is embedded in AC and DC power supplies, electrochemical processes, heating and lighting control, electronic welding, photovoltaic and fuel cell power conversion, and motor drives. Power electronics play a central role in industrial automation, high-efficiency energy systems, energy conservation, renewable energy systems, and electric and hybrid vehicles.

Bardeen_Shockley_Brattain_1948Early power electronics technologies included mercury-arc rectifiers for converting AC to DC power, hot-cathode ray tube rectifiers first invented by GE, and virtually indestructible magnetic amplifiers. The modern era of solid-state electronics launched in 1948 with the invention of the transistor at Bell Labs. From the Computer History Museum:

Using improved semiconductor materials developed for radar detectors during the war, in early 1945 [William] Shockley experimented with a field-effect amplifier, similar in concept to those patented by Heil and Lilienfeld, but it failed to work as he intended. Physicist John Bardeen suggested that electrons on the semiconductor surface might be blocking penetration of electric fields into the material. Under Shockley’s direction, together with physicist Walter Brattain, Bardeen began researching the behavior of these “surface states.” On December 16, 1947, their research culminated in a successful semiconductor amplifier. Bardeen and Brattain applied two closely-spaced gold contacts held in place by a plastic wedge to the surface of a small slab of high-purity germanium. On December 23 they demonstrated their device to lab officials and in June 1948, Bell Labs publicly announced the revolutionary solid-state device they called a “transistor.”

Today, power MOSFETs, which first appeared on the market in the 1970s, have become popular for low-voltage, high frequency applications. The insulated-gate bipolar transistor (IGBT or IGT), invented in 1983, is the most popular semiconductor device for medium-to-high power applications.

Improving Transmission Efficiency with Busbars

Rogers-new-RO-LINX-Power-Circuit-BusbarsAs the need for power increased after WWII, it became important to improve power transmission efficiency and reduce switching losses within electrical devices.

Rogers developed the busbar product line – strips or bars of copper, brass, or aluminum that collect and distribute electricity within electrical devices –in 1959 as an engineering solution to the problem of power distribution in the first transistorized computer, the IBM 1401. These busbars quickly captured a main share of the growing computer market.

By the mid-1960s, virtually all manufacturers of mainframe computers were Rogers’ customers. This was the company’s first significant step toward vertical integration from materials into components, using Rogers’ materials as the base. This was to become one of the key aspects of growth in the next twenty years.

Significant research has taken power distribution technology to the next level. Today that takes three forms at Rogers: ROLINX® busbars, curamik® ceramic substrates, and curamik® cooling solutions.

ROLINX PowerCircuit busbars help attain higher power efficiencies by limiting switching losses. They serve as power distribution “highways” that connect power sources with capacitors, IGBTs, or complete modules. These busbars combine the traits of traditional laminated busbars with the processing capabilities of PCB assemblies. The result is a high-performance busbar that supports 3D design, helps achieve optimum thermal management, and is well suited for medium-to-high-volume assembly processes.

Power Substrates for High Heat Conductivity

curamikIn 2011, Rogers acquired curamik Electronics GmbH, a manufacturer of power electronic substrate products headquartered in Eschenbach, Germany. Founded in 1983, curamik develops and produces direct copper bonded (DCB) ceramic substrate products used in the design of intelligent power management devices, such as IGBT modules.

These ceramic substrates are found in a growing array of clean technologies that are powering the world. The basis of the substrate is a ceramic isolator to which pure copper is applied. The result is ceramic substrates with high heat conductivity and great heat capacity, and heat spreading provided by the thick copper layer.

curamik’s DBC (Direct Bond Copper) substrates are manufactured by bonding copper foils directly to electrically insulating industrial ceramics. curamik also uses AMB technology (Active Metal Brazing), another form of joining metal to ceramic. The result is customized ceramic substrates for highly efficient thermal management, providing high-performance electrical power management.

Rogers Corporation provides innovative solutions for power electronics, advanced foams for cushioning and protective sealing, and high-frequency printed circuit materials. For over 180 years, we have empowered breakthroughs in reliability, efficiency, and performance, to help our customers build a cleaner, safer, and more connected world.

 

 

 

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