Category Archives: LED Manufacturing

Richard Friend of the Cavendish Laboratory, at the University of Cambridge and colleagues, have blended poly(9,9-dioctylfluorene) (F8) and a poly(para-phenylenevinylene) (PPV) copolymer known as Super Yellow (SY) and used cesium carbonate in their LED’s negative electrode to minimize quenching and give them ultrahigh efficiency devices.

Balancing the charges in the emissive layer of a polymer light emitting diode (PLED) maximizes light output from the device, the researchers report. Many teams have attempted to achieve perfect charge balance by introducing hole transport layers, that carry the “opposite” of electrons, positive holes, using electron injection layers and tuning polymer blends to improve energy transfer. There is, however, always a trade-off between electronic and optical properties. Friend and his colleagues hoped that PLEDs with ultrahigh luminous efficiency, low operating voltage and reasonably large current density should be possible.

By blending the right polymers at the right levels (in this case 9 parts F8 to 1 part SY), the team has now been able to manipulate how well holes can move, hole-mobility, by exploiting the difference in energy levels, the molecular orbitals, of the polymers. Additionally, they swapped the conventional calcium-aluminum negative electrode, cathode, system for one containing a thin layer of cesium carbonate. This layer allows electrons to be efficiently injected into the LED in order to stimulate light emission.

The team reports an ultrahigh efficiency in their device of approximately 27 candelas per amp. In comparison a device based only on SY rather than the polymer blend lights up to only about 12.5 cd/A. This “excellent performance” for the blended device, the team suggests, arises because of the intrinsic hole trapping nature of the blend system, which they explain is further enhanced by accomplishing a perfect charge balance via efficient electron injection.

“The next step could be further optimization of the performance by varying the thickness of the emissive layer and calcium carbonate,” explains team member Muhammad Umair Hassan. “Our experiments reveal that this optimization is very important.”

LG Innotek, a leading global materials and components manufacturer, today announced that the company started to produce high-power LED packages (H35C4 Series) featuring 180lm/W, which are the highest efficacy in the world.

LG Innotek improves the efficacy of high-power LED packages by 13% compared to the previous packages. The Company said that the H35C4 Series will be supplied to the global market in October.

LG Innotek used its proprietary vertical LED chip technology to optimize the manufacturing and mixing process of the fluorescent substance that produces the light for its LED chips, thus improving the performance of their LED packages. This performance is at least 10% better than all other competing products.

These LED packages boast a efficacy of 152lm/W at 85℃, 700mA under the actual usage environment of most LED packages. It beats the efficacy of competing products by 10lm/W or more.

Through optimizing “white conversion technology”, the lifespan of the product has also in-creased greatly. According to the expected lifespan based on LM-80, the LED lighting reliability evaluation criteria used by the US Environmental Protection Agency (EPA), the average lifespan of LG Innotek’s product is 150,000 hours. This is almost three times longer than existing products, which have a lifespan of 51,000 hours.

In addition, LG Innotek has established a product line-up that encompass all ranges of color temperatures and rendering, including warm white (2700K), neutral white (5000K), cool day-light (6500K), and High CRI (CRI>90). Customers can apply these products for their use in LED lighting.

LG Innotek will further stay focused on developing high performance and value product such as High Power LED Package featuring more than 5 watt and UV LED. The company also has a plan to enhance its LED lighting line-up for automotive as well mobile application.

DuPont Displays today announced the opening of a state-of-the-art, scale-up manufacturing facility designed to deliver production scale quantities of advanced materials that enable large-format, solution-based printed Organic Light Emitting Diode (OLED) displays. These materials are designed to help manufacturers develop OLED displays that are brighter, more vivid, longer lasting and significantly less expensive than the OLED TVs on the market today. The facility is located at the DuPont Stine-Haskell Research Center (Stine-Haskell) in Newark, Del., near DuPont’s global headquarters in Wilmington.

“Materials are critical to the performance of an OLED TV and we are confident that DuPont has the best performing solution OLED materials available in the market today,” said Avi Avula, global business director, DuPont Displays. “Our vision is that OLEDs will become the display standard and to make that vision a reality, we are focused on helping our customers bring the cost of large sized OLED TVs down to less than $1000 by 2020.”

DuPont’s new scale-up facility is sized to meet the future growth expectations of the OLED TV industry, which analysts predict will increase by over 70 percent for the next several years and will require large quantities of highly sophisticated OLED materials. DuPont has been developing its suite of advanced OLED materials for the last 15 years. These materials are highly regarded for both solution and evaporative applications due to their long lifetime and deep color. In addition to its recently announced collaboration with an inkjet equipment maker to advance solution printed displays, DuPont is actively engaged with the leading OLED display manufacturers to bring solution printed OLED technology to market as quickly as possible.

DuPont’s new OLED facility at Stine-Haskell has large-scale formulation systems and can support simultaneous production of multiple product lines. It was designed with a focus on employee safety, environmental responsibility and producing superior quality materials with the highest possible purity. The project was partially funded by a grant from the state of Delaware in 2012, with DuPont investing more than $20 million in the facility.

DuPont Displays brings more than 15 years of experience in enabling evaporative and solution-based OLED technologies through advanced materials that deliver the color, efficiency and lifetime performance that display manufacturers and consumers demand. DuPont offers highly engineered, next-generation OLED materials as well as solution process know-how that makes the promise of lower cost OLED technology commercially feasible for TVs and other large-format displays.

Transparency Market Research (TMR), a market intelligence company based in the U.S., projects the global organic electronics market to grow at a CAGR of 32.6% from 2012 to 2018. The report, titled “Organic Electronics Market – Global Industry Analysis, Market Size, Share, Growth and Forecast 2012-2018”, is available on the company website for sale. The TMR study points out that the organic electronics market has tremendous potential in the fields of display technologies and electronic circuits, and is expected to register high growth rates in the coming years. The growth of the organic electronics market will be boosted by a combination of OLED lighting, OLED displays, OFRID, and organic photovoltaics.

As per the TMR study, the displays segment held the largest share of the organic electronics market. For the purpose of the study, the displays segment is segregated into electrophoretic, OLED displays, and other displays. Of these, OLED displays are projected to lead the organic electronics market and are projected to be worth US$10,450 million by 2018. This is due to their low energy consumption, high-speed performance, and sharp display features. Further, the study found the electrophoretic sub-segment is projected to be worth US$3,950 million by 2018, growing at a CAGR of 58.4% for the study period. Additionally, the continuous expansion of end-use applications beyond OLED lighting, OLED displays, and organic photovoltaics (OPV) is responsible for the robust growth of the global organic electronics market, as per the study analysis. Moreover, RFID labels and logic and memory are increasingly becoming the prime focus for OE manufacturers due to the high usage of these segments in the organic electronics market.

TMR’s findings show organic electronics will mostly be newly created rather than used as a replacement for other existing electronics, which will drive the growth of the market. Moreover, organic electronics, in spite of being capable of complemented with conventional silicon electronics, have the ability to produce flexible circuits. Owing to this trait, organic electronics have a rapidly increasing application base for flexible displays such as intelligent textiles, RFID labels, e-paper, bio-sensors, and intelligent packaging.

For the purpose of the study, the global organic electronics market is segmented into Asia Pacific, the U.S., Europe, and Rest of the World (RoW). In the geographical scenario, Asia Pacific is expected to lead the organic electronics market by revenue till 2018. As per the TMR research findings, Asia Pacific will boast a 50% share of the total revenue of the global organic electronics market in 2018 and will be followed by Europe.

As a response to meet the increasing demands (higher heat/brightness characteristics) of cutting-edge LED technologies, Shin-Etsu Silicones of America (SESA), a U.S. subsidiary of Shin-Etsu Chemical Co. Ltd. of Japan, has recently introduced its new optically clear LIMS (Liquid Injection Molding System) X-34-1972-3 material.

With a transparency of 95%, the new material is ideal for expanding LED applications in street lighting, automotive, and exterior illumination. Notably, its high temperature resistance, compared to thermoplastic resins, allows molded silicone optics to be positioned in close proximity to the LED light source without yellowing or cracking over extended operating life spans.

According to SESA’s North America Marketing Manager, Eric Bishop, “Next-generation HBLED systems are getting hotter as light output continues to increase. The advanced engineering properties of our X-34-1972-3 material delivers unparalleled heat resistance and clarity at these higher operating temperatures.”

Bishop also noted that the material has been tested in-house and at customers with promising results.

The optically clear LIMS X-34-1972-3 material will be on display during SESA’s open-house demonstration at their LIMSTM Technical Center in Akron, Ohio on Monday, October 12 (1:00 pm – 5:00 pm). The informal event will feature the production of 100% silicones magnifying lenses and the opportunity to network with industry suppliers and associates.

X-34-1972-3 properties:

  • Viscosity (A/B): 450/450 Pa.s
  • Hardness: 70 A
  • Tensile Strength: 7.5 MPa
  • Tear Strength: 12kN/m
  • Refractive Index: 1.41
  • Transparency: 95%

Until now, transparent electrode materials for OLEDs have mainly consisted of indium tin oxide (ITO), which is expected to become economically challenging for the industry due to the shrinking abundance of indium. Therefore, scientists are intensively looking for alternatives. One promising candidate is graphene, whose application fields are more closely investigated in the project GLADIATOR (“Graphene Layers: Production, Characterization and Integration”).

The project GLADIATOR, which is funded by the European Commission, has reached its midterm and has already achieved some successes. The aim of the project is the cost-effective production of high quality graphene at large area, which can then be used for numerous electrode applications. The usability of such applications will be demonstrated at the Fraunhofer FEP by integrating this graphene in OLEDs.

With graphene as an electrode, the researchers at the Fraunhofer FEP hope for flexible devices with higher stability. Beatrice Beyer, project coordinator, says: “Graphene is a very interesting material with many possibilities. Because of its opto-electrical properties and its excellent mechanical stability, we expect that the reliability of flexible electronics will be improved many times over.”

Graphene is a rediscovered modification of carbon with two-dimensional structure, which has gained enormously in popularity since its successful isolation in 2004. Such so-called “monolayer” graphene is synthesized on a metal catalyst via a chemical vapor deposition (CVD) process and transferred by a further process step to a target substrate, such as thin glass or plastic film. Here, it is very important that no defects are added which might reduce the quality of the electrode. In order to compete with the reference material ITO, the transparency and conductivity of graphene must be very high. Therefore, not only is the process of electrode manufacturing being optimized, but also different ways of doping graphene to improve its properties are being examined.

At the same time, the developed process steps must be easily scalable for later industrial use. These many challenges are faced by a project consortium consisting of 16 partners from six EU member states and Switzerland.

The Fraunhofer FEP is coordinating the GLADIATOR project and acts as an end-user of the graphene electrode. Scientists examine the integration of graphene and compare it to the reference material ITO. The sophisticated material properties of graphene must be maintained during the integration in organic devices. To this end, several methods for cleaning and structuring the graphene must be modified. In addition, the processes for different target substrates such as glass or flexible foil must be adapted and optimized. The first hurdles have been overcome thanks to a close cooperation between the consortium partners and the first defect-free OLEDs on transparent graphene electrodes have been realized on small areas. The target of the next one and a half years is to successfully illuminate large area OLEDs.

The GLADIATOR project will run until April 2017. By this time several types of OLED will have been made using graphene electrodes: a white OLED with an area of about 42 cm2 to demonstrate the high conductivity, and a fully-flexible, transparent OLED with an area of 3 cm2 to confirm the mechanical reliability.

Imagine illuminating your home or business with flat, inexpensive panels that are environmentally friendly, easy on your eyes, and energy-efficient because they create minimal heat.

Now imagine how those panels could be used if they were as flexible as paper or cloth; the technology could be bent into shapes, fit the interior or exterior curves of vehicles, even be incorporated into clothing.

In “Flexible organic light-emitting diodes (OLEDs) for solid-state lighting” a team of researchers at Pohang (Republic of Korea) University of Science and Technology reports on advances in three key areas — flexible electrodes, flexible encapsulation methods, and flexible substrates — that make commercial use of such technology more feasible and closer to implementation. The article appears in the current issue of the Journal of Photonics for Energy, published by SPIE, the international society for optics and photonics.

Figure 9 from a new article in the Journal of Photonics for Energy is a schematic illustration of OLED structures with encapsulation: (a) conventional glass lid and (b) thin-film encapsulation. Credit: Min-Ho Park et al., Pohang University

Figure 9 from a new article in the Journal of Photonics for Energy is a schematic illustration of OLED structures with encapsulation: (a) conventional glass lid and (b) thin-film encapsulation. Credit: Min-Ho Park et al., Pohang University

OLEDs show promise as a future light source because of their thinness, light weight, energy efficiency, and use of environmentally benign materials. Companies such as Philips and LG Chemical have begun producing flat OLED panels that produce non-glare, UV-free light but very little heat, with no need for lamp shades or diffusers.

“The future trend in OLEDs is to make them on plastic substrates for flexibility, durability, and light weight. In this work, the authors review the technical challenges and solutions in this important subject,” said Franky So, Walter and Ida Freeman Distinguished Professor in Materials Science and Engineering at North Carolina State University, and an associate editor of the journal.

Min-Ho Park and other researchers at Pohang tested a variety of transparent electrodes as flexible alternatives to currently available devices based on indium tin oxide (ITO), which is brittle and increasingly expensive, and identified next steps toward making flexible solid-state lighting commercially feasible:

  • development of a flexible electrode that has high electrical conductivity, high bending stability, few defects, smooth surface texture, and high work function
  • reduction in the water-vapor transmission rate of materials used, to counter the vulnerability of OLEDs to moisture.

OLEDs produce light by sending electricity through one or more thin layers of an organic semiconductor, which may be composed of any of a variety of materials and as small a as a molecule. The semiconductor is sandwiched between a positively charged electrode and a negatively charged one. These layers are deposited on a supporting surface called a substrate, and protected from exposure to the air by a thin layer of encapsulants (traditionally glass).

The Pohang team demonstrated good electrical, optical, and mechanical performance with flexible electrodes fabricated using graphene, conducting polymers, silver nanowires (AgNWs), and dielectric-metal-dielectric (DMD) multilayer structures.

However, various obstacles still remain with these devices’ durability, conductivity, surface roughness, and fabrication cost. Current flexible substrates and encapsulation methods are being explored, with the goal of reducing cost and processing time, and increasing durability.

Researchers from Holst Centre (set up by TNO and imec), imec and CMST, imec’s associated lab at Ghent University, have demonstrated the world’s first stretchable and conformable thin-film transistor (TFT) driven LED display laminated into textiles. This paves the way to wearable displays in clothing providing users with feedback.

Wearable devices such as healthcare monitors and activity trackers are now a part of everyday life for many people. Today’s wearables are separate devices that users must remember to wear. The next step forward will be to integrate these devices into our clothing. Doing so will make wearable devices less obtrusive and more comfortable, encouraging people to use them more regularly and, hence, increasing the quality of data collected. A key step towards realizing wearable devices in clothing is creating displays that can be integrated into textiles to allow interaction with the wearer.

“Wearable devices allow people to monitor their fitness and health so they can live full and active lives for longer. But to maximize the benefits wearables can offer, they need to be able to provide feedback on what users are doing as well as measuring it. By combining imec’s patented stretch technology with our expertise in active-matrix backplanes and integrating electronics into fabrics, we’ve taken a giant step towards that possibility,” says Edsger Smits, Senior research scientist at Holst Centre.

The conformable display is very thin and mechanically stretchable. A fine-grain version of the proven meander interconnect technology was developed by the CMST lab at Ghent University and Holst Centre to link standard (rigid) LEDs into a flexible and stretchable display. The LED displays are fabricated on a polyimide substrate and encapsulated in rubber, allowing the displays to be laminated in to textiles that can be washed. Importantly, the technology uses fabrication steps that are known to the manufacturing industry, enabling rapid industrialization.

Following an initial demonstration at the Society for Information Display’s Display Week in San Jose, USA earlier this year, Holst Centre has presented the next generation of the display at the International Meeting on Information Display (IMID) in Daegu, Korea, 18-21 August 2015. Smaller LEDs are now mounted on an amorphous indium-gallium-zinc oxide (a-IGZO) TFT backplane that employs a two-transistor and one capacitor (2T-1C) pixel engine to drive the LEDs. These second-generation displays offer higher pitch and increased, average brightness. The presentation will feature a 32×32 pixel demonstrator with a resolution of 13 pixels per inch (ppi) and average brightness above 200 candelas per square meter (cd/m2). Work is ongoing to further industrialize this technology.

The world’s first stretchable and conformable thin-film transistor (TFT) driven LED display laminated into textiles developed by Holst Centre, imec and CSMT.

The world’s first stretchable and conformable thin-film transistor (TFT) driven LED display laminated into textiles developed by Holst Centre, imec and CSMT.

RayVio Corporation, a developer of deep ultraviolet (UV) LEDs and integrated solutions, announced today that they are expanding their international sales force, and manufacturing capacity. The facility expansion at the original site is scheduled to be complete by year-end.

RayVio’s current Silicon Valley headquarters houses their wafer growth, chip fabrication, packaging and test R&D and proto-typing capability. The expansion of this facility will enable RayVio to reduce cycle time and produce in excess of two million LED units annually through the installation of additional manufacturing and test equipment. Combined with its contract manufacturing strategy, RayVio is poised to keep pace with the increasing demand of the fast growing deep UV LED market.

The demand is being driven by a host of industrial and consumer applications ranging from water disinfection to consumer medical devices serving multiple global markets.

“Our proven, novel technology platform is producing best in class performance, and at the same time we are executing against our cost reduction roadmap, allowing our downstream partners to make their products a reality,” says Dr. Doug Collins, Vice President of Engineering and Operations.

Until recent achievements in both performance and cost, UV LED solutions were limited to niche applications. With the availability of high optical power UV LEDs, and competitive system level pricing to alternative UV sources, the UV LED industry is seeing a major uptake in solutions being provided.

“RayVio’s superior performance and cost effective solutions have accelerated the mass adoption of UV LED enabled industrial and consumer devices,” says Dr. Robert C. Walker, RayVio co-founder and CEO.  “With the funding we received earlier this year, we have the capital required to grow the company aggressively. By expanding our international sales force and increasing our manufacturing and research capabilities, we will be well positioned to maintain a leadership role.”

RayVio came out of stealth mode at the beginning of 2015 after closing their $9.3M series B round of financing.  They are currently sampling selected customers, and are working closely with industry leading partners in the UV LED curing, medical device and water, surface and air disinfection markets.

Advances at Oregon State University in manufacturing technology for “quantum dots” may soon lead to a new generation of LED lighting that produces a more user-friendly white light, while using less toxic materials and low-cost manufacturing processes that take advantage of simple microwave heating.

The cost, environmental, and performance improvements could finally produce solid state lighting systems that consumers really like and help the nation cut its lighting bill almost in half, researchers say, compared to the cost of incandescent and fluorescent lighting.

The same technology may also be widely incorporated into improved lighting displays, computer screens, smart phones, televisions and other systems.

A key to the advances, which have been published in the Journal of Nanoparticle Research, is use of both a “continuous flow” chemical reactor, and microwave heating technology that’s conceptually similar to the ovens that are part of almost every modern kitchen.

The continuous flow system is fast, cheap, energy efficient and will cut manufacturing costs. And the microwave heating technology will address a problem that so far has held back wider use of these systems, which is precise control of heat needed during the process. The microwave approach will translate into development of nanoparticles that are exactly the right size, shape and composition.

“There are a variety of products and technologies that quantum dots can be applied to, but for mass consumer use, possibly the most important is improved LED lighting,” said Greg Herman, an associate professor and chemical engineer in the OSU College of Engineering.

“We may finally be able to produce low cost, energy efficient LED lighting with the soft quality of white light that people really want,” Herman said. “At the same time, this technology will use nontoxic materials and dramatically reduce the waste of the materials that are used, which translates to lower cost and environmental protection.”

Some of the best existing LED lighting now being produced at industrial levels, Herman said, uses cadmium, which is highly toxic. The system currently being tested and developed at OSU is based on copper indium diselenide, a much more benign material with high energy conversion efficiency.

Quantum dots are nanoparticles that can be used to emit light, and by precisely controlling the size of the particle, the color of the light can be controlled. They’ve been used for some time but can be expensive and lack optimal color control. The manufacturing techniques being developed at OSU, which should be able to scale up to large volumes for low-cost commercial applications, will provide new ways to offer the precision needed for better color control.

By comparison, some past systems to create these nanoparticles for uses in optics, electronics or even biomedicine have been slow, expensive, sometimes toxic and often wasteful.

Oher applications of these systems are also possible. Cell phones and portable electronic devices might use less power and last much longer on a charge. “Taggants,” or compounds with specific infrared or visible light emissions, could be used for precise and instant identification, including control of counterfeit bills or products.

OSU is already working with the private sector to help develop some uses of this technology, and more may evolve. The research has been supported by Oregon BEST and the National Science Foundation Center for Sustainable Materials Chemistry.