Tag Archives: letter-leds-tech

The darkest form of ultraviolet light, known as UV-C, is unique because of its reputation as a killer – of harmful organisms.

With wavelengths of between 200 and 280 nanometers, this particular form of UV light penetrates the membranes of viruses, bacteria, mold and dust mites, attacking their DNA and killing them. Sanitization with UV-C light has been around for more than 100 years, following Niels Finsen’s discovery of UV light as an antidote to tuberculosis, which won the Faroese-Danish physician the 1903 Nobel Prize for Medicine.

Currently, most deep-UV lamps are mercury-based. They pose a threat to the environment, and are bulky and inefficient. A Cornell research group led by Huili (Grace) Xing and Debdeep Jena, along with collaborators from the University of Notre Dame, has reported progress in creating a smaller, more earth-friendly alternative.

Using atomically controlled thin monolayers of gallium nitride (GaN) and aluminum nitride (AlN) as active regions, the group has shown the ability to produce deep-UV emission with a light-emitting diode (LED) between 232 and 270 nanometer wavelengths. Their 232- nanometer emission represents the shortest recorded wavelength using GaN as the light-emitting material. The previous record was 239 nanometers, by a group in Japan.

“MBE-grown 232-270 nm deep-UV LEDs using monolayer thin binary GaN/AlN quantum heterostructures” was published online Jan. 27 in Applied Physics Letters.

Postdoctoral researcher SM (Moudud) Islam, the lead author, said: “UV-C light is very attractive because it can destroy the DNA of species that cause infectious diseases, which cause contamination of water and air.”

One of the major challenges with ultraviolet LEDs is efficiency, which is measured in three areas: injection efficiency – the proportion of electrons passing through the device that are injected into the active region; internal quantum efficiency (IQE) – the proportion of all electrons in the active region that produce photons or UV light; and light extraction efficiency – the proportion of photons generated in the active region that can be extracted from the device and are actually useful.

“If you have 50 percent efficiency in all three components … multiply all of these and you get one-eighth,” Islam said. “You’re already down to 12 percent efficiency.”

In the deep-UV range, all three efficiency factors suffer, but this group found that by using gallium nitride instead of conventional aluminum gallium nitride, both IQE and light extraction efficiency are enhanced.

Injection efficiency is improved through the use of a polarization-induced doping scheme for both the negative (electron) and positive (hole) carrier regions, a technique the group explored in previous work.

Now that the group has proven its concept of enhanced deep-UV LED efficiency, its next task is packaging it in a device that could one day go on the market. Deep-UV LEDs are used in food preservation and counterfeit currency detection, among other things.

Further study will include packaging both the new technology and existing technologies in otherwise similar devices, for the purpose of comparison.

“In terms of quantifying the efficiency, we do want to package it within the next few months and test it as if it was a product, and try to benchmark it against a product with one of the available technologies,” Jena said.

Seoul Semiconductor Europe, a subsidiary of Seoul Semiconductor Co. Ltd. today announced the availability of reference modules based on its package-free Wicop LEDs.

“We found that offering module solutions, based on our highly innovative technologies, will allow our customers to evaluate the technology and its benefits easily, enabling them to realize their solutions faster than by just using LED components”, Mr. Andreas Weisl, CEO Seoul Semiconductor Europe and Vice President Sales, explained. “Resources at our customers are often limited, so they need powerful, reliable and easy to handle solutions to meet their requirements. As a solution provider, we help them to be ahead of competition and to achieve a fast time-to-market, also by creating customized modules in our Munich-based lab, we are able to offer,” he added.

This first release includes reference modules for the Wicop Y19, Y22 and Y22P LEDs. The Y19 module consists of four clusters of 2 x 2 LEDs with a combined typical flux of 4,650 lumens, while the Y22 and Y22P modules achieve 1,268 lumens with four single LEDs each. They all feature a Color Rendering Index (CRI) of 70 and a Correlated Color Temperature (CCT) of 4,000 K.

All modules announced today are tailored to common customer needs and follow the outlines given in book 15 of the Zhaga specification, which defines the location and pitch of the LEDs and the position and size of the alignment holes for optical lenses. The boards feature standard power connectors and are easy to assemble and easy to use together with commercially available lenses, like the new Wilma lens-array from LEDiL.

Wicop LEDs with their luminous efficiency of up to 210 lm/W at 350 mA are well suited as light-source for applications for example such as wall washers or floodlights in the architectural space and lighting in warehouses or production sites in the industrial area. Outdoor they can be used for example for street lighting, in tunnels or for the illumination of stadiums, harbors, airports or railway stations, as well as for security applications.

Their compact footprint makes these LEDs several times smaller and much brighter than conventional LEDs, enabling cost savings at the system level. This is achieved through its state of the art chip design with the phosphor film directly attached to the chip surface, making the previously needed packaging with frames and gold wires obsolete. This way, Wicop LEDs are also suitable for applications, where a small form factor is needed.

The three reference modules introduced today are available from Seoul Semiconductor Europe. Production quantities can be provided on request. If necessary, they can also be customized by Seoul Semiconductor’s regional labs for special requirements.

Dow Corning further expanded the design flexibilities for LED packaging manufacturers today with the addition of five new optical encapsulants (OEs) to its portfolio of advanced LED solutions. Offering extra high thermal and optical stability with optimized refractive indexes, hardness and gas barrier properties, these five new products broaden design latitudes for very high power LED packages, such as ceramic substrate-based surface mount device (SMD), chip on-board (COB) and plastic leaded chip carrier (PLCC) packaging.

All introduced under the Dow Corning label, the five new products include OE-7840, OE-7841, OE-7843, OE-7810 and OE-7820 Optical Encapsulants. They fall into two separate categories of targeted performance properties, but all deliver superior photothermal stability and reliability at sustained temperatures of 150°C.

“As today’s LED manufacturers continue to design brighter, smaller and more cost-effective LED packages, Dow Corning is working closely with them to evolve advanced new silicone solutions to meet their most demanding challenges,” said Takuhiro Tsuchiya, global marketing manager at Dow Corning. “These five cutting-edge optical encapsulants build on the success of our industry-leading OE product family, and enable customers to continue pushing the design boundaries for their high-power LED packages.”

Three of the products – Dow Corning OE-7840, Dow Corning® OE-7841 and Dow Corning® OE-7843 Optical Encapsulants – provide OEMs optimized refractive indexes and other features to improve both efficiency and reliability of high-power PLCC LED packages. The OE-7840 and OE-7841 products respectively offer RIs of 1.5 and 1.48 to allow designers to optimize light output while ensuring their LED packages have good gas barrier properties. OE-7843 Encapsulant rounds this category out by combining an RI of 1.5 with good anti-silver corrosion properties to enable high-power PLCC LED packages to withstand severe environmental conditions.

The two remaining new products – Dow Corning OE-7810 and Dow Corning OE-7820 Optical Encapsulants – target high-power COB and ceramic substrate-based SMD LED packages, where very high thermal resistance is the priority and corrosive silver is not used. They offer a choice of durometer tailored to improve durability depending on design parameters. OE-7810 Encapsulant provides a hardness of Shore A55 for packaging applications that require higher elongation for improved durability under thermal cycling. OE-7820 Encapsulant, with a durometer of Shore A70, delivers higher hardness that can contribute to better handling and minimal dust pick up.

LG Innotek today announced that the company has developed the world’s first 70mw UV-C LED for sterilization applications. As its sterilization performance is 1.5 times higher than the competitor’s 45mW module.

UV-C LED produces the short wavelength ultraviolet rays in the range of 200 — 280nm, allowing it to be used for sterilization purpose. It prevents the proliferation of bacteria by destroying their DNA. LG Innotek’s product emits UV in the range of 280nm.

Until now, UV-C LED has been mainly applied in small sanitary products because its low optical power led to low sterilization performance. The power of LEDs for toothbrush sterilizers is 1mW and that for sterilizing the water tank of humidifier is 2mW.

LG Innotek improved UV-C LED’s optical power to 70mW by utilizing its proprietary LED vertical chip technology. While the product measures only 6mm in both its length and width, its sterilization performance is the world’s best.

The company overcomes the UV output limit with specialized LED chip technology. The epitaxial structure design and vertical chip technology to maximize light extraction have increased the output and ensured quality reliability by effectively exhausting heat.

As the company’s product is compact and boasts high sterilization performance, it can be applied to various fields such as water purifiers and air purifiers as it allows you to sterilize flowing water and air.

It is also good for use in hardening equipment in the manufacturing industry. The UV output is strong, the performance of the curing device can be enhanced.

Manufacturers of water purification, cleaning and curing device can benefit from stable supply of UV-C LEDs optimized for respective purposes from LG Innotek. Because LG Innotek is equipped with a consistent production system that produces Epi-wafers, chips, packages, and modules, and offers its products to its customers after rigorous quality management.

Along with its 280nm UV-C LED, LG Innotek has a lineup of LEDs from 365nm, 385nm, 395nm, and 405nm UV-A LEDs for general industrial purposes to 305nm UV-B LEDs for bio and medical purposes.

According to Yole Development, a market research firm, the UV LED market is forecast to grow from 130 million USD in 2015 to 270 million USD in 2017.

innotek

Leti, a research institute of CEA Tech, today announced it has developed a μLED fabrication process to create high-resolution arrays at 10-micron pitch. That pixelization and the 873 x 500 resolution that are enabled by the new process exceed technology.

Designed for micro-display applications such as augmented-reality or virtual-reality tools and wearable devices, the blue or green GaN/InGaN µLED arrays use Leti’s proprietary self-aligned technology. That process is key to achieving such a small pixel pitch. A combination of several damascene metallization steps used to create a common cathode is also expected to provide good thermal dissipation and prevent voltage drops within the micro-LED matrix. Electro-optical measurements showcase record efficiency and brightness exceeding requirements for device integration.

The results were presented Feb. 2 at SPIE Photonics West in San Francisco in a paper: “Processing and Characterization of High-Resolution GaN/InGaN LED Arrays at 10-Micron Pitch for Micro-Display Applications”.

“Leti’s self-aligned process allows the creation of high-resolution µLED matrices with a reduced pixel pitch of 10µm and paves the way towards even smaller pitches for next-generation devices,” said Ludovic Dupré, one of the paper’s authors. “In addition, the use of the damascene metallization process of the cathode, which also is a new process developed at Leti, is a breakthrough compared to previous demonstrations of micro-LED matrices. The common cathode indeed fills the whole volume between the micro-LEDs and provides metallic spreading of electrical current between them, as well as thermal dissipation. These results are promising for integrating a micro-LED matrix in micro-display devices by hybridization on CMOS active matrices, and first prototypes are currently being tested.”

ROHM has recently announced the availability of an ultra-compact reflector-type LED optimized for consumer devices such as matrix light sources for gaming and wearables that demand increased miniaturization.

The MSL0402RGBU reflector-type 3-color LED leverages miniaturization technology cultivated over many years to achieve the smallest size in the industry (1.8mmx1.6mm). This enables high-density mounting and provides excellent color mixing characteristics, ensuring support for high resolution LED matrices.

In order to turn on matrix light sources it is necessary to take measures against ESD. Unlike conventional solutions that utilize a Zener diode, the MSL0402RGBU adopts an element with high ESD resistance. This makes it possible to superior ESD protection without a Zener diode and prevent light emission of unnecessary blocks in matrix circuits, resulting in clearer display.

In recent years, LEDs capable of representing the full color range are expected to be widely adopted in a variety of fields, including digital signage requiring improved design flexibility. At the same time, as applications become smaller and more sophisticated the need for greater expressiveness grows, along with increased miniaturization and long-term reliability. Up to now, ROHM offers ultra-compact molded type LEDs (PICOLED), high brightness reflector types (MSL series), and compact high brightness 3-color LEDs with excellent color mixing, but to meet market demands ROHM developed the industry’s smallest high brightness reflector-type RGB LEDs (MSL0402RGBU).

rohm led

At next week’s SPIE Photonics West in San Francisco, imec, a research and innovation hub in nano-electronics and digital technologies, will introduce a new image sensor with integrated color (Red Green Blue, RGB) and narrow-band near-infrared (NIR) filters. This breakthrough optical filter integration platform will enable many different application fields from medical, industrial, security surveillance, automotive to virtual and augmented reality, where near-infrared signals need to be extracted and overlaid on top of color images.

Imec’s RGB-NIR multispectral platform demonstrates for the very first time the possibility to integrate together standard RGB color filters, NIR-cut filter, NIR narrow band-pass filters and on-chip microlenses technology, down to small pixels as small as 5µm today. The NIR band-pass filter and design pattern implementation can be tuned to match requirements of a specific application case, e.g. the wavelength of a particular laser or LED light.

“An affordable, high resolution and high speed solution for integrating true RGB color combined with narrow-band NIR detection was essential to develop for future applications that need to detect or track near infra-red signals that should not be visible to human eyes,” explains Andy Lambrechts, program manager for imec’s integrated imaging activities. “This capability to integrate a color view with one or several near-infrared narrow bands will be a key enabler for next-generation 3D, virtual reality (VR) & augmented reality (AR) imaging platforms. As well as in machine vision, medical, automotive and security surveillance applications.”

Leveraging imec’s background in CMOS scaling, its semiconductor fab, equipment and process technology, imec designs and manufactures interference based optical filters at wafer level, deposited and patterned directly on top of the CMOS image sensor pixels. Imec’s unique infrastructure provides very integrated, clean (class 1 – particle free) and high yield optical filter integration with strong potential for scalability in high-volume.

The first image sensor and camera prototypes will be demonstrated at SPIE Photonics West in San-Francisco on booth 4333 (North Hall of Moscone center). They are already available for early sampling and evaluation by strategic partners.

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ams AG (SIX: AMS), a provider of high performance sensor solutions and analog ICs, today launched the world’s first series of cost-effective multispectral sensor-on-chip solutions, opening the way for a new generation of spectral analyzers for consumer and industrial applications.

Offered in a small 4.5 x 4.4mm land grid array package, the ultra-low power AS7262 visible range sensor and AS7263 NIR sensor each provide six calibrated spectral channels. Because of their attractive price point, the new multispectral sensors open the door to testing and use in a very wide range of consumer and real-world field applications. Key solution spaces include material and product authentication, product quality and integrity as well as material content analysis in the near-infrared (NIR) and visible spectrums.

“In much the same way that intense sensor integration into our smartphones and tablets has created a tidal wave of new mobile applications, the launch of the AS7262 and AS7263, enabling chip-scale spectral analysis, heralds a similar revolution that will open the door wide for spectral sensing innovation for both industrial and consumer applications,” commented Jean Francois Durix,
Marketing Director for Emerging Sensor Systems at ams. “The dramatic reduction in the size and cost of spectral analysis enabled by our new spectral sensing solutions brings the lab to the sample for an incredible variety of applications from food safety and product authentication, to routine
testing that can better protect both our health and our environment.”

The multispectral sensors employ a new fabrication technique which enables nano-optical interference filters to be deposited directly on the CMOS silicon die with extreme precision. This interference filter technology used for the sensors offers extremely precise and reproduceable filter characteristics which are stable over both time and temperature and are much smaller and more cost-effective than the components typically used in today’s spectral analysis instruments.

The AS7262 six-channel visible light sensor with integrated intelligence provides a calibrated digital output over an I2C or UART interface. It measures light intensity at six wavelengths in the visible light spectrum: 450nm, 500nm, 550nm, 570nm, 600nm and 650nm. The AS7263 operates in the NIR spectrum detecting 610nm, 680nm, 730nm, 760nm, 810nm and 860nm infrared signatures. Both devices include an electronic shutter with LED drive circuitry, which means that device de-signers can accurately control the light source and the spectral sensing functions with a single chip.

The small size of the new multispectral sensors combined with their low power consumption enable measurement equipment OEMs to develop new product types that take advantage of these unique attributes. For instance, bulky laboratory-grade analysis equipment can now be replaced by conve-nient handheld form factors. In factories, samples which today have to be removed from the production line and taken to a laboratory for chemical analysis or quality testing will be tested in-line by new small, robust spectral analyzers based on the multispectral sensors.

The AS7262 and AS7263 are in volume production now. Unit pricing is $4.00 in order quantities of 1,000.

Dow Corning significantly expanded the design flexibilities for LED packaging manufacturers today with the addition of three new highly reflective silicone coatings to its fast-growing portfolio of advanced LED solutions. Offering targeted solutions for cutting-edge LED designs – such as chip scale (CSP) and chip on-board (COB) packaging – the three new products also deliver versatile processing options ranging from conventional dispensing to emerging printing methods.

All introduced under the Dow Corning label, the three new products include WR-3001 Die Edge Coat, WR-3100 Die Edge Coat and WR-3120 Reflective Coating. In the future, products are planned to be added to match customer required processes.

“Manufacturers are aggressively seeking to design smaller, more efficient and cost-effective LED packages, which is driving demand for advanced new reflective materials that enable evolving application processes such as printing, and withstand increasingly stringent operating conditions,” said Takuhiro Tsuchiya, global marketing manager at Dow Corning. “These three cutting-edge coatings are only the first of a range of new products that we have in store for the industry. A proactive and collaborative innovator, Dow Corning formulated these three reflective silicone coatings specifically to help customers overcome today’s greatest design challenges and deliver highly reliable and differentiated products in the fiercely competitive LED market.”

As with all of Dow Corning reflective materials, the three new grades maintain high reflectivity at low thicknesses and retain their performance at sustained temperatures of 150°C – a temperature at which many organic coatings crack and yellow. Listed in order of increasing hardness, the new products include:

  • WR-3001 Die Edge Coat targets high-power CSP applications that demand LED materials with high thermal- and photostability. It is compatible with conventional dispensing processes.
  • WR-3100 Die Edge Coat is formulated for CSP applications and low- to middle-power LED package designs. Compatible with conventional dispensing equipment, it delivers comparatively high hardness of Shore D 65 after cure, making it suitable with chip dicing processes.
  • WR-3120 Reflective Coating also provides high thermal- and photostability suitable for high-power LED packaging applications, as well as the highest hardness of Dow Corning’s three new products. Suitable for printing processes, this advanced silicone further offers the highest reflectivity for enhanced LED performance.

A market leader in materials, expertise and collaborative innovation for LED lighting concepts, Dow Corning offers solutions that span the entire LED value chain, adding reliability and efficiency for sealing, protecting, adhering, cooling and shaping light across all lighting applications.

Wolfspeed, a Cree Company and a developer of silicon carbide (SiC) power products, has introduced a 900V, 10mΩ MOSFET rated for 196 A of continuous drain current at a case temperature of 25̊̊ C. This device enables the reduction of EV drive-train inverter losses by 78 percent based on EPA combined city/highway mileage standards. This efficiency improvement offers designers new options in terms of range, battery usage and vehicle design.

Recently Wolfspeed supplied Ford Motor Company―in a collaboration with the U.S. DoE―with a full-SiC, 400A power module designed around the 900V, 10mΩ chip. The module, designed and produced by Wolfspeed, contains four MOSFETs connected in parallel to achieved a remarkable 2.5mΩ Rds(on). Wolfspeed engineers have since demonstrated the capability to use these chips to create an 800A, 1.25mΩ module.

“With the commercial release of the 900V 10mΩ device, electric vehicles can now reap the benefits of SiC in all aspects of their power conversion,” said John Palmour, CTO of Wolfspeed. “With the continued expansion of our Gen3 MOSFET portfolio in new package options, our devices can now support significant efficiency improvements in onboard chargers, offboard chargers, and now EV drive trains.”

Commercially qualified and rated for a maximum operating temperature of 175˚C, Wolfspeed’s new chip offers high-reliability in harsh environments, like those found in vehicle drive-trains.

Device Information

The new 900V, 10mΩ MOSFET is available in bare die, is listed as part number CPM3-0900-0010A, and is currently available for purchase from SemiDice. Wolfspeed expects to release the associated discrete device in a 4L-TO247 package (C3M0010090K) in the coming weeks. This package has a Kelvin-source connection that allows engineers to create designs that maximize the benefits of SiC’s superior speed and efficiency.

For more complete technical information about Wolfspeed’s new 900V, 10mΩ MOSFET, access its part page here.