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A capacitive touch sensor display that provides a more intuitive interface to ease and accelerate user interactions has been developed by VCC. The LED-based CTH series capacitive touch sensor display combines graphic interactive control with colour identification to make the interface more user-friendly.Utilising sensitive capacitive touch sensing technology, the CTH series simplifies designs and offers cost savings by eliminating the need for a traditional switch.The LED display produces a high-optical clarity, and is offered with or without a wide variety of standard graphic overlays and colours. VCC can also develop custom icons to meet most any application requirement. Offered in a wide variety of colours including red, yellow, blue, pure green and white, the LED back-lit CTH series. The robust design has no moving parts, improving reliability and increasing the operational life.Featuring a through hole design, the capacitive touch sensor display is available in one standard size 15x15x11.0mm with an industry standard pitch of 0.100"."Featuring translucent icons illuminated with different coloured LEDs, the user friendly CTH series display offers superior device interaction by communicating a singular action to users such as on/off, alarm status, and more," said Sannah Vinding, Director of Product Development and Marketing at VCC. "The integrated functionality of the compact CTH series capacitive touch sensor display eliminates the need for designing-in a traditional switch. Unlike mechanical membrane switches or mechanical push buttons, capacitive touch keypads have no moving parts so there is nothing to wear out."The CTH series is used in a wide range of applications including appliances, consumer equipment, gaming devices, industrial control displays, media players, medical devices, mobile communication devices, PDAs, point of sale terminals, portable instruments, touch screen monitors and more.Reference:T141AM61STMPE1208SQTRQT1101-ISGAT42QT2100-AUR  

Use of copper as a fluorescent material allows for the manufacture of inexpensive and environmentally compatible organic light-emitting diodes (OLEDs). Thermally activated delayed fuorescence (TADF) ensures high light yield. Scientists of Karlsruhe Institute of Technology (KIT), CYNORA, and the University of St Andrews have now measured the underlying quantum mechanics phenomenon of intersystem crossing in a copper complex. The results of this fundamental work are reported in the Science Advances journal and contribute to enhancing the energy efficiency of OLEDs.  Organic light-emitting diodes are deemed tomorrow's source of light. They homogeneously emit light in all observation directions and produce brilliant colors and high contrasts. As it is also possible to manufacture transparent and flexible OLEDs, new application and design options result, such as flat light sources on window panes or displays that can be rolled up. OLEDs consist of ultra-thin layers of organic materials, which serve as emitter and are located between two electrodes. When voltage is applied, electrons from the cathode and holes (positive charges) from the anode are injected into the emitter, where they form electron-hole pairs. These so-called excitons are quasiparticles in the excited state. When they decay into their initial state again, they release energy.Excitons may assume two different states: Singlet excitons decay immediately and emit light, whereas triplet excitons release their energy in the form of heat. Usually, 25 percent singlets and 75 percent triplets are encountered in OLEDs. To enhance energy efficiency of an OLED, also triplet excitons have to be used to generate light. In conventional light-emitting diodes heavy metals, such as iridium and platinum, are added for this purpose. But these materials are expensive, have a limited availability, and require complex OLED production methods.It is cheaper and environmentally more compatible to use copper complexes as emitter materials. Thermally activated delayed fluorescence (TADF) ensures high light yields and, hence, high efficiency: Triplet excitons are transformed into singlet excitons which then emit photons. TADF is based on the quantum mechanics phenomenon of intersystem crossing (ISC), a transition from one electronic excitation state to another one of changed multiplicity, i.e. from singlet to triplet or vice versa. In organic molecules, this process is determined by spin-orbit coupling. This is the interaction of the orbital angular momentum of an electron in an atom with the spin of the electron. In this way, all excitons, triplets and singlets, can be used for the generation of light. With TADF, copper luminescent material reaches an efficiency of 100 percent.Stefan Bräse and Larissa Bergmann of KIT's Institute of Organic Chemistry (IOC), in cooperation with researchers of the OLED technology company CYNORA and the University of St Andrews, United Kingdom, for the first time measured the speed of intersystem crossing in a highly luminescent, thermally activated delayed fluorescence copper(I) complex in the solid state. The results are reported in the Science Advances journal. The scientists determined a time constant of intersystem crossing from singlet to triplet of 27 picoseconds (27 trillionths of a second). The reverse process – reverse intersystem crossing – from triplet to singlet is slower and leads to a TADF lasting for an average of 11.5 microseconds. These measurements improve the understanding of mechanisms leading to TADF and facilitate the specific development of TADF materials for energy-efficient OLEDs.Reference:KY59-0202NYKY59-S101D2LCD-S301C31TR 

How can quantum information be stored as long as possible? An important step forward in the development of quantum memories has been achieved by a research team of TU Wien.Conventional memories used in today's computers only differentiate between the bit values 0 and 1. In quantum physics, however, arbitrary superpositions of these two states are possible. Most of the ideas for new quantum technology devices rely on this "Superposition Principle". One of the main challenges in using such states is that they are usually short-lived. Only for a short period of time can information be read out of quantum memories reliably, after that it is irrecoverable.A research team at TU Wien has now taken an important step forward in the development of new quantum storage concepts. In cooperation with the Japanese telecommunication giant NTT, the Viennese researchers lead by Johannes Majer are working on quantum memories based on nitrogen atoms and microwaves. The nitrogen atoms have slightly different properties, which quickly leads to the loss of the quantum state. By specifically changing a small portion of the atoms, one can bring the remaining atoms into a new quantum state, with a lifetime enhancement of more than a factor of ten. These results have now been published in the journal Nature Photonics.Nitrogen in diamond"We use synthetic diamonds in which individual nitrogen atoms are implanted", explains project leader Johannes Majer from the Institute of Atomic and Subatomic Physics of TU Wien. "The quantum state of these nitrogen atoms is coupled with microwaves, resulting in a quantum system in which we store and read information."However, the storage time in these systems is limited due to the inhomogeneous broadening of the microwave transition in the nitrogen atoms of the diamond crystal. After about half a microsecond, the quantum state can no longer be reliably read out, the actual signal is lost. Johannes Majer and his team used a concept known as "spectral hole burning", allowing data to be stored in the optical range of inhomogeneously broadened media, and adapted it for supra-conducting quantum circuitsand spin quantum memories.Dmitry Krimer, Benedikt Hartl and Stefan Rotter (Institute of Theoretical Physics, TU Wien) have shown in their theoretical work that such states, which are largely decoupled from the disturbing noise, also exist in these systems. "The trick is to manoeuver the quantum system into these durable states through specific manipulation, with the aim to store information there," explains Dmitry Krimer.Excluding specific energies"The transitions areas in the nitrogen atoms have slightly different energy levels because of the local properties of the not quite perfect diamond crystal", explains Stefan Putz, the first author of the study, who has since moved from TU Wien to Princeton University. "If you use microwaves to selectively change a few nitrogen atoms that have very specific energies, you can create a "Spectral Hole". The remaining nitrogen atoms can then be brought into a new quantum state, a so-called "dark state", in the center of these holes. This state is much more stable and opens up completely new possibilities.""Our work is a 'proof of principle' – we present a new concept, show that it works, and we want to lay the foundations for further exploration of innovative operational protocols of quantum data," says Stefan Putz.With this new method, the lifetime of quantum states of the coupled system of microwaves and nitrogen atoms increased by more than one order of magnitude to about five microseconds. This is still not a great deal in the standard of everyday life, but in this case it is sufficient for important quantum-technological applications. "The advantage of our system is that one can write and read quantum information within nanoseconds," explains Johannes Majer. "A large number of working steps are therefore possible in microseconds, in which the system remains stable."Reference: S29GL032N11FFIS42S29GL064N90FFIS30S29AS016J70BFA040  

Using state-of-the-art theoretical methods, UCSB researchers have identified a specific type of defect in the atomic structure of a light-emitting diode (LED) that results in less efficient performance. The characterization of these point defects could result in the fabrication of even more efficient, longer lasting LED lighting."Techniques are available to assess whether such defects are present in the LED materials and they can be used to improve the quality of the material," said materials professor Chris Van de Walle, whose research group carried out the work.In the world of high-efficiency solid-state lighting, not all LEDs are alike. As the technology is utilized in a more diverse array of applications—including search and rescue, water purification and safety illumination, in addition to their many residential, industrial and decorative uses—reliability and efficiency are top priorities. Performance, in turn, is heavily reliant on the quality of the semiconductor material at the atomic level."In an LED, electrons are injected from one side, holes from the other," explained Van de Walle. As they travel across the crystal lattice of the semiconductor—in this case gallium-nitride-based material—the meeting of electrons and holes (the absence of electrons) is what is responsible for the light that is emitted by the diode: As electron meets hole, it transitions to a lower state of energy, releasing a photon along the way.Occasionally, however, the charge carriers meet and do not emit light, resulting in the so-called Shockley-Read-Hall (SRH) recombination. According to the researchers, the charge carriers are captured at defects in the lattice where they combine, but without emitting light.The defects identified involve complexes of gallium vacancies with oxygen and hydrogen. "These defects had been previously observed in nitride semiconductors, but until now, their detrimental effects were not understood," explained lead author Cyrus Dreyer, who performed many of the calculations on the paper."It was the combination of the intuition that we have developed over many years of studying point defects with these new theoretical capabilities that enabled this breakthrough," said Van de Walle, who credits co-author Audrius Alkauskas with the development of a theoretical formalism necessary to calculate the rate at which defects capture electrons and holes.The method lends itself to future work identifying other defects and mechanisms by which SRH recombination occurs, said Van de Walle."These gallium vacancy complexes are surely not the only defects that are detrimental," he said. "Now that we have the methodology in place, we are actively investigating other potential defects to assess their impact on nonradiative recombination."Reference:KY59-LM324MMKY59- LM2710KY59- LM3080 

An ultra-compact implantable image sensor using body channel communication has been demonstrated in Japan. The body channel approach allows the sensor-transmitter device to be much smaller and use less power than an RF wireless unit.  Fundamental limitsInterest in implantable medical sensors is on the rise as developments in established technologies and new concepts are making more and more applications feasible. One thing that all such sensors share is the need to be able to get the information they gather within the body, out of the body.RF communication is widely used for such applications, however, with implantable devices size reduction is generally desirable to reduce invasiveness, and in some applications there are also specific size limitations, owing to where and how the sensors are to be implanted. For example, sensors intended for use inside the brain need to be very compact.Using smaller antennas generally means using higher frequencies, and that in turn leads to attenuation problems with biological tissues. To compensate for increased attenuation more power is needed, which is also a serious issue for an implantable device.Conductive communicationAn alternative wireless approach to sending the data is body channel communication, in which an electrical signal is transmitted by conduction through the tissues of the body. In this issue of Electronics Letters, researchers from the Nara Institute of Science and Technology's Graduate School of Materials Science report using this approach to transmit and receive image data from a CMOS sensor fully implanted in a simulated body environment.Their sensor design, using body channel as the transmission method, will allow data to be read from the device by attaching an electrode to the surface of the body near the implantation site, as well as allowing the sensor unit itself to be low-power and small."Our implantable CMOS image sensor is intended for biomedical applications such as brain functional imaging," explains team member Hajime Hayami. "It can be planted with minimum invasiveness. Its features enable implantation of a number of sensors in a brain to investigate collaborative neural activities."In their experiments, the team at Nara have transmitted images from a CMOS sensor submerged in phosphate buffer saline (PBS), a body simulant material, to a receiver electrode 2 mm away. The experiments prove the principle of operation for this form of communication and even this small distance is enough to allow in vivo use in smaller animals."We are planning to apply our device to brain functional imaging of a mouse brain in the near future. Because the size of a mouse brain is only a few mm thick, the transmission distance of 2 mm is sufficient. Even in the case of signal transmission through a longer distance with a larger animal, the experimental results indicate that this method can be applied by adjusting the sensitivity of the receiver circuit," said Hayami.Neural arraysBefore the team can proceed with implantation in an animal, they need to integrate all of their PCB based devices into a single chip. This chip has already been designed and they are now working on the fabrication, with the goal of beginning implantation experiments by the end of 2014.Meanwhile, the Nara researchers have also been working to develop the design and say that relatively long distance transmission is now possible through improvements to the receiver circuit. On the sensor/transmitter side, they have also shown that they can use pulse-width modulation rather than an ADC output from the image sensor.The central goal of their work is creating tools for research into the human brain. "Our research group aims to elucidate the cooperative neural activity with distributed ultra-small sensors in the brain. We think we can achieve the goal by designing more intelligent chips based on the proposed communication method," said Hayami.The team believe that current sociological trends, including aging societies, will continue to drive demand for implantable devices, and that the applications of this kind of technology may develop to include more natural interaction between users and technology. Hayami commented that "I hope we will create an epoch where one can unconsciously use implantable devices by developing a brain-machine interface."Reference:KY45-OVM7695-RAEAKY45- OV09726-A40A-1DKY45- MT9P001I12STC 

The Telecontrolli capacitive rain sensor detects precipitation rate, current precipitation intensity and its end with precision and effectiveness, avoiding false positives which can cause inappropriate operations (objects such as dirt or other particles that in preexisting optical sensors cause a reflection mimicking the one of rain and limit its effectiveness in rapidly responding to light rain).Capacitive sensing is a technology based on the change in capacity determined by the change of the dielectric constant of the material separating the electrical conductors (plates) of the capacitor following the action of external agents.Capacitive sensing is becoming a popular technology to replace optical detection methods and mechanical designs for applications like proximity/gesture detection, material analysis and rain/humidity detection, because it offers more reliable and accurate measurements than optical ones.The sensor has IDT electrodes on one side of the alumina substrate, while a resistive heater and a temperature sensor are placed on the opposite side. The rain sensitive area, which in dry conditions assumes the nominal value of 100pF. Moreover in presence of the rain, the capacitance goes to high values compared to dry conditions and the ratio changing is over 300%.The integral and configurable heater is provided to ensure that the detection surface dries quickly, protecting the surface from fog, condensed moisture and frost. It also can be disabled when power consumption is critical.The alumina substrate and the glass sensitive layer makes the sensor immune to water and moisture absorption, ensuring high resistance and long duration.Moreover, thanks to the thermal conductivity of the ceramic, the heat emitted by the heater on the back of the sensor is immediately transferred to the upper surface, making the sensor more sensitive than other technologies.Furthermore, while resistive rain sensors are sensible to corrosion and contamination, the Telecontrolli capacitive rain sensor doesn't suffer from these disadvantages, making it suitable for any type of application - including irrigation systems for agriculture, automotive wiper systems, weather stations, and applications for home and building automation.