David Savastano, Editor01.31.12
Not all great ideas come from meticulous planning and research. Sometimes, excellent ideas can be the result of an accident. Such is the case with Quantum Tunnelling Composites (QTC), a pressure switching and sensing material technology developed by David and Chris Lussey, founders of Peratech Limited, Richmond, UK.
David Lussey, co-founder and chief technical officer of Peratech, had retired as a specialist officer from the Royal Air Force after a 30-year career. Lussey had set up a civilian business in 1990, and discovered QTC in 1996.
“I was trying out different formulas to make a conductive adhesive,” Lussey noted. “As I was dismantling one particular experiment, I noticed that the resistance dropped dramatically when I attempted to pull apart two metal strips bound together with one particular formulation.
“Most people would have just thrown it away and got back to the task in hand, but I was intrigued with this counter-intuitive resistance change and investigated the material further,” Lussey continued. “Putting metal particles into a polymer to make a conductive material has been known about for years, but I had mixed the metal particles and the adhesive binder in a polythene mortar and pestle which imparted low shear forces to the mix. The result was QTC and its unique properties.”
Lussey took his findings to Durham University, a local university, where Professor David Bloor confirmed that conduction was occurring because of a quantum effect, not from the touching of the metal particles.
“This was a completely new area of material science, and I was able to take out a patent on the manufacturing process to make QTC, which effectively means that Peratech, the company I founded in 1997 to exploit this invention, is the only company that can make QTC,” Lussey said. “Peratech has continued to research QTC and currently has more than 100 QTC patents worldwide. Durham University has a department to this day that just investigates the properties of QTC, making this a rare instance of a University spin-in.”
What is QTC?
QTC is made from a polymer that has nanoscale conductive particles, each with a “spikey” surface, evenly distributed throughout. The spikes don't actually touch, but when the material has a force applied, such as pressure, the spikes move closer together and a quantum effect occurs in that the electrons leap or tunnel from one spike tip to the next and a current flows until the pressure is removed. Thus, QTC provides a change in resistance that is proportional to the pressure applied – from almost infinite resistance when not under force to almost zero when pressed.
Lussey said that for its first few years, Peratech investigated QTC, to determine how to make it reliably and how changes to the polymer, the conductive materials used and the size and shape of the particles resulted in QTC materials with very different performance characteristics.
“For example, the overall resistance range can be chosen, and the sensitivity can range from being so sensitive that a thin film of QTC can act as a microphone to being so insensitive that it takes the weight of a tank to activate it,” Lussey noted.
“Remove the pressure and the resistance returns to what it was originally – a cycle that can be reliably repeated time and time again as there are no mechanical parts to wear out,” he added. “Also, the anisotropic properties of QTC can be controlled to impart unique functionality to white boards, touch screens and large-area devices.”
Since Peratech's original discovery of Quantum Tunnelling Composites, Peratech has continually researched this rich area of material science. From the original “bulk” elastomeric QTC materials, the company has extended its range of QTC materials to include QTC Inks - emulsive materials that are applied by silk screen process.
Announced last year, Peratech continues to push the boundaries of QTC functionality with QTC Clear - a transparent version of QTC Inks with a huge potential to revolutionize the rapidly growing touchscreen industry.
Markets for QTC
Potential uses for QTC are numerous, ranging from textiles to touch screens.
“One of the first applications for QTC was in clothing, where controls for iPods and similar devices could be integrated into a jacket,” Lussey noted. “Effectively a flexible, textile, solid state switch, it can be washed or dry cleaned, crumpled and stretched. A number of design wins were achieved with high-end ski brands and suit makers but the volumes were small.
As QTC is effectively the next stage in the evolution of the switch, almost any application where a switch is used could have a QTC replacement. Some of the more unusual applications include NASA using QTC for the fingertips of a robotic astronaut, MIT using QTC to create a touch sensitive skin to cover a robot, and automotive manufacturers for a variety of in car uses such as QTC sensors in seats to provide not only information that a person is in a seat but also how much they weigh so that the air bag can be deployed appropriately.
Touch screens have been another area where QTC is having success. The production of QTC Touchscreens is simple, as the QTC material is supplied as an ink that is screen-printed directly onto the electrode layers of one of the substrates. This makes it easy for existing resistive manufacturers to quickly switch from printing spacer dots to printing the QTC layer. Peratech has already signed a multi-million dollar license deal for this touchscreen technology to a major manufacturer.
Peratech also has designed a QTC-based navigation keypad that was licensed by Samsung Electro-mechanics in 2010, and is in commercially available in a number of mobile phones. Meanwhile, Peratech is entering new markets
“Peratech continues to advance the state-of-the art in working with our materials in creating new applications in conjunction with our licensees in areas such as mobile phones and consumer electronic devices, automotive, touchscreens, computer input devices, healthcare and toys and games, to name a few,” Lussey said.
Peratech’s business is essentially the IP licensing model, which has been proven to be rapidly scalable and highly profitable for the likes of ARM and many others. It is profitable with 100% of sales being to overseas customers. Peratech has a growing number of license agreements, some of which are worth millions of dollars.
Peratech dedicates teams to each customer to ensure that they receive the best possible service from people that understand their aims and goals resulting in license relationships that are generally in excess of three years.
The ability to print QTC ink is a key advantage of Peratech’s technologies.
“All QTC Ink, including QTC Clear technologies, are applied by silk screen printing process,” Lussey said. “Peratech manufactures the silk screen QTC Ink material, and it is this that is provided to our licensee customers for application by their own print manufacturing facilities or subcontractors.
Without a doubt, Lussey is extremely optimistic about the impact of QTC in many different markets.
“Our customers are excited about the ability to reduce cost and improve their environmental footprint by switching to printed electronics, moving away from traditional circuit board and FPC technologies,” Lussey said. “Peratech's QTC Ink products are at the core of this, and we remain very focused on servicing this growing market sector.”
David Lussey, co-founder and chief technical officer of Peratech, had retired as a specialist officer from the Royal Air Force after a 30-year career. Lussey had set up a civilian business in 1990, and discovered QTC in 1996.
“I was trying out different formulas to make a conductive adhesive,” Lussey noted. “As I was dismantling one particular experiment, I noticed that the resistance dropped dramatically when I attempted to pull apart two metal strips bound together with one particular formulation.
“Most people would have just thrown it away and got back to the task in hand, but I was intrigued with this counter-intuitive resistance change and investigated the material further,” Lussey continued. “Putting metal particles into a polymer to make a conductive material has been known about for years, but I had mixed the metal particles and the adhesive binder in a polythene mortar and pestle which imparted low shear forces to the mix. The result was QTC and its unique properties.”
Lussey took his findings to Durham University, a local university, where Professor David Bloor confirmed that conduction was occurring because of a quantum effect, not from the touching of the metal particles.
“This was a completely new area of material science, and I was able to take out a patent on the manufacturing process to make QTC, which effectively means that Peratech, the company I founded in 1997 to exploit this invention, is the only company that can make QTC,” Lussey said. “Peratech has continued to research QTC and currently has more than 100 QTC patents worldwide. Durham University has a department to this day that just investigates the properties of QTC, making this a rare instance of a University spin-in.”
What is QTC?
QTC is made from a polymer that has nanoscale conductive particles, each with a “spikey” surface, evenly distributed throughout. The spikes don't actually touch, but when the material has a force applied, such as pressure, the spikes move closer together and a quantum effect occurs in that the electrons leap or tunnel from one spike tip to the next and a current flows until the pressure is removed. Thus, QTC provides a change in resistance that is proportional to the pressure applied – from almost infinite resistance when not under force to almost zero when pressed.
Lussey said that for its first few years, Peratech investigated QTC, to determine how to make it reliably and how changes to the polymer, the conductive materials used and the size and shape of the particles resulted in QTC materials with very different performance characteristics.
“For example, the overall resistance range can be chosen, and the sensitivity can range from being so sensitive that a thin film of QTC can act as a microphone to being so insensitive that it takes the weight of a tank to activate it,” Lussey noted.
“Remove the pressure and the resistance returns to what it was originally – a cycle that can be reliably repeated time and time again as there are no mechanical parts to wear out,” he added. “Also, the anisotropic properties of QTC can be controlled to impart unique functionality to white boards, touch screens and large-area devices.”
Since Peratech's original discovery of Quantum Tunnelling Composites, Peratech has continually researched this rich area of material science. From the original “bulk” elastomeric QTC materials, the company has extended its range of QTC materials to include QTC Inks - emulsive materials that are applied by silk screen process.
Announced last year, Peratech continues to push the boundaries of QTC functionality with QTC Clear - a transparent version of QTC Inks with a huge potential to revolutionize the rapidly growing touchscreen industry.
Markets for QTC
Potential uses for QTC are numerous, ranging from textiles to touch screens.
“One of the first applications for QTC was in clothing, where controls for iPods and similar devices could be integrated into a jacket,” Lussey noted. “Effectively a flexible, textile, solid state switch, it can be washed or dry cleaned, crumpled and stretched. A number of design wins were achieved with high-end ski brands and suit makers but the volumes were small.
As QTC is effectively the next stage in the evolution of the switch, almost any application where a switch is used could have a QTC replacement. Some of the more unusual applications include NASA using QTC for the fingertips of a robotic astronaut, MIT using QTC to create a touch sensitive skin to cover a robot, and automotive manufacturers for a variety of in car uses such as QTC sensors in seats to provide not only information that a person is in a seat but also how much they weigh so that the air bag can be deployed appropriately.
Touch screens have been another area where QTC is having success. The production of QTC Touchscreens is simple, as the QTC material is supplied as an ink that is screen-printed directly onto the electrode layers of one of the substrates. This makes it easy for existing resistive manufacturers to quickly switch from printing spacer dots to printing the QTC layer. Peratech has already signed a multi-million dollar license deal for this touchscreen technology to a major manufacturer.
Peratech also has designed a QTC-based navigation keypad that was licensed by Samsung Electro-mechanics in 2010, and is in commercially available in a number of mobile phones. Meanwhile, Peratech is entering new markets
“Peratech continues to advance the state-of-the art in working with our materials in creating new applications in conjunction with our licensees in areas such as mobile phones and consumer electronic devices, automotive, touchscreens, computer input devices, healthcare and toys and games, to name a few,” Lussey said.
Peratech’s business is essentially the IP licensing model, which has been proven to be rapidly scalable and highly profitable for the likes of ARM and many others. It is profitable with 100% of sales being to overseas customers. Peratech has a growing number of license agreements, some of which are worth millions of dollars.
Peratech dedicates teams to each customer to ensure that they receive the best possible service from people that understand their aims and goals resulting in license relationships that are generally in excess of three years.
The ability to print QTC ink is a key advantage of Peratech’s technologies.
“All QTC Ink, including QTC Clear technologies, are applied by silk screen printing process,” Lussey said. “Peratech manufactures the silk screen QTC Ink material, and it is this that is provided to our licensee customers for application by their own print manufacturing facilities or subcontractors.
Without a doubt, Lussey is extremely optimistic about the impact of QTC in many different markets.
“Our customers are excited about the ability to reduce cost and improve their environmental footprint by switching to printed electronics, moving away from traditional circuit board and FPC technologies,” Lussey said. “Peratech's QTC Ink products are at the core of this, and we remain very focused on servicing this growing market sector.”