Tag Archives: letter-leds-tech

By Zvi Or-Bach, President & CEO, MonolithIC 3D Inc.

As we have predicted two and a half years back, the industry is bifurcating, and just a few products pursue scaling to 7nm while the majority of designs stay on 28nm or older nodes.

Our March 2014 blog Moore’s Law has stopped at 28nm has recently been re-confirmed. At the time we wrote: “From this point on we will still be able to double the amount of transistors in a single device but not at lower cost. And, for most applications, the cost will actually go up.” This reconfirmation can be found in the following IBS cost analysis table slide, presented at the early Sept FD-SOI event in Shanghai.

Gate costs continue to rise each generation for FinFETs, IBS predicts.

Gate costs continue to rise each generation for FinFETs, IBS predicts.

As reported by EE Times – Chip Process War Heats Up, and quoting Handel Jones of IBS “28nm node is likely to be the biggest process of all through 2025”.

IBS prediction was seconded by “Samsung executive showed a foil saying it believes 28nm will have the lowest cost per transistor of any node.” The following chart was presented by Samsung at the recent SEMICON West (2016).

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And even Intel has given up on its “every two years” but still claims it can keep reducing transistor cost. Yet Intel’s underwhelming successes as a foundry suggests otherwise. We have discussed it in a blog titled Intel — The Litmus Test, and it was essentially repeated by SemiWiki’s Apple will NEVER use Intel Custom Foundry!

This discussion seems academic now, as the actual engineering costs of devices in advanced nodes have shown themselves to be too expensive for much of the industry. Consequently, and as predicted, the industry is bifurcating, with a few products pursuing scaling to 7nm while the majority of designs use 28nm or older nodes.

The following chart derived from TSMC quarterly earnings reports was published last week by Ed Sperling in the blog Stepping Back From Scaling:

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Yes, the 50-year march of Moore’s Law has ended, and the industry is now facing a new reality.

This is good news for innovation, as a diversity of choices helps support new ideas and new technologies such as 3D NAND, FDSOI, MEMS and others. These technologies will enable new markets and products such as the emerging market of IoT.

A good opportunity to learn more about these new scaling technologies is the IEEE S3S ’16, to be held in the Hyatt Regency San Francisco Airport, October 10th thru 13th, 2016. It starts with 3D and FDSOI tutorials, the emerging technologies for the IC future. CEA Leti is scheduled to give an update on their CoolCube program, Qualcomm will present some of their work on monolithic 3D, and three leading researchers from an imec, MIT, and Korea university collaboration will present their work on advanced monolithic 3D integration technologies. Many other authors will discuss their work on monolithic 3DIC and its ecosystem, in addition to tracks focused on SOI, sub-VT and dedicated sessions on IoT.

“Promising” and “remarkable” are two words U.S. Department of Energy’s Ames Laboratory scientist Javier Vela uses to describe recent research results on organolead mixed-halide perovskites.

Perovskites are optically active, semiconducting compounds that are known to display intriguing electronic, light-emitting and chemical properties. Over the last few years, lead-halide perovskites have become one of the most promising semiconductors for solar cells due to their low cost, easier processability and high power conversion efficiencies. Photovoltaics made of these materials now reach power conversion efficiencies of more than 20 percent.

Vela’s research has focused on mixed-halide perovskites. Halides are simple and abundant, negatively charged compounds, such as iodide, bromide and chloride. Mixed-halide perovskites are of interest over single-halide perovskites for a variety of reasons. Mixed-halide perovskites appear to benefit from enhanced thermal and moisture stability, which makes them degrade less quickly than single-halide perovskites, Vela said. He added they can be fine-tuned to absorb sunlight at specific wavelengths, which makes them useful for tandem solar cells and many other applications, including light emitting diodes (LEDs).Using these compounds, scientists can control the color and efficiency of such energy conversion devices.

Speculating that these enhancements had something to do with the internal structure of mixed-halide perovskites, Vela, who is also an associate professor of chemistry at Iowa State University (ISU), worked with scientists with expertise in solid-state nuclear magnetic resonance (NMR) at both Ames Laboratory and ISU. NMR is an analytical chemistry technique that provides scientists with physical, chemical, structural and electronic information about complex samples.

“Our basic question was what it is about these materials in terms of their chemistry, composition, and structure that can affect their behavior,” said Vela.

Scientists found that depending on how the material is made there can be significant nonstoichiometric impurities or “dopants” permeating the material, which could significantly affect the material’s chemistry, moisture stability and transport properties.

The answers came via the combination of the use of optical absorption spectroscopy, powder X-ray diffraction and for the first time, the advanced probing capabilities of lead solid-state NMR.

“We were only able to see these dopants, along with other semicrystalline impurities, through the use of lead solid-state NMR,” said Vela.

Another major discovery scientists made was that solid state synthesis is far superior to solution-phase synthesis in making mixed-halide perovskites. According to Vela, the advanced spectroscopy and materials capabilities of Ames Laboratory and ISU were critical in understanding how various synthetic procedures affect the true composition, speciation, stability and optoelectronic properties of these materials.

“We found you can make clean mixed halide perovskites without semi-crystalline impurities if you make them in the absence of a solvent,” Vela said.

According to Vela, the significance of their findings is multifold and they are only beginning to grasp the implications of those findings.

“One obvious implication is that our understanding of the amazing opto-electronic properties of these semiconductors was incomplete,” said Vela. “We’re dealing with a compound that is not inherently as simple as people thought.”

The research is further discussed in a paper, “Persistent Dopants and Phase Segregation in Organolead Mixed-Halide Perovskites,” authored by Vela, Bryan A. Rosales, Long Men, Sarah D. Cady, Michael P. Hanrahan, and Aaron J. Rossini; and published online in Chemistry Materials. The work was supported by DOE’s Office of Science.

Samsung Electronics Co., Ltd. today announced “H-series Gen 3,” a new line-up of LED linear modules that features high efficacy and enables easy replacement of fluorescent lights with LED lamps.

New Samsung LED H-series linear module for indoor lighting (Graphic: Business Wire)

New Samsung LED H-series linear module for indoor lighting (Graphic: Business Wire)

“With our new H-series, Samsung continues to lead the high-end industry segment for LED components through constant technology innovation,” said Jacob Tarn, executive vice president, LED Business Team, Samsung Electronics. “We are directing our technology expertise to improving the quality of LED lighting by significantly enhancing our LED components’ performance and overall competitiveness.”

Samsung’s H-series Gen 3 provides light efficacy reaching up to 187 lumen per watt (lm/W) at 4000K, which allows LED luminaires using the modules to achieve light efficacy above 140lm/W, delivering an optic efficiency level of about 86 percent and LED driver efficiency of approximately 88 percent.

Currently, Samsung offers several linear LED module line-ups: the V-series for cost-effective applications; the M-, S- and F-series for standard LED lighting segments; and now the H-series for high-performance LED products.

Samsung’s H-series Gen 3 uses the LM561C, the mid-power LED package with the highest efficacy in its LM561-series line-up. As a result, the H-series Gen 3 has obtained 18 to 26 percent higher efficacy than the company’s M-series Gen 2 modules. This feature makes the H-series Gen 3 line-up well-suited to meet DLC Premium standards – technical requirements for LED lighting solutions suggested by DesignLights Consortium™. DLC standards are well recognized in the North American region as a preferred means of evaluating LED lighting products in terms of performance and quality.

The H-series comes in three sizes: 1120mm (4 ft.) 560mm (2 ft.) and 280mm/275mm (1 ft.). As the premium version of the company’s M-series and S-series line-ups, the H-series has the same form factors as those modules (see chart below), while providing a performance level that more than satisfies the high demands of the U.S. and EU luminaire markets.

Samsung’s M-series has been certified by UL, a product quality certification standards organization in the U.S., while the S-series has been certified by CE and ENEC, similar standards bodies in the EU. Sharing the form factors and quality certifications of Samsung’s M- and S-series, the H-series allows lighting manufacturers to select their LED modules according to the specific operating conditions of their applications.

A powerful new material developed by Northwestern University chemist William Dichtel and his research team could one day speed up the charging process of electric cars and help increase their driving range.

An electric car currently relies on a complex interplay of both batteries and supercapacitors to provide the energy it needs to go places, but that could change.

“Our material combines the best of both worlds — the ability to store large amounts of electrical energy or charge, like a battery, and the ability to charge and discharge rapidly, like a supercapacitor,” said Dichtel, a pioneer in the young research field of covalent organic frameworks (COFs).

Dichtel and his research team have combined a COF — a strong, stiff polymer with an abundance of tiny pores suitable for storing energy — with a very conductive material to create the first modified redox-active COF that closes the gap with other older porous carbon-based electrodes.

“COFs are beautiful structures with a lot of promise, but their conductivity is limited,” Dichtel said. “That’s the problem we are addressing here. By modifying them — by adding the attribute they lack — we can start to use COFs in a practical way.”

And modified COFs are commercially attractive: COFs are made of inexpensive, readily available materials, while carbon-based materials are expensive to process and mass-produce.

Dichtel, the Robert L. Letsinger Professor of Chemistry at the Weinberg College of Arts and Sciences, is presenting his team’s findings today (Aug. 24) at the American Chemical Society (ACS) National Meeting in Philadelphia. Also today, a paper by Dichtel and co-authors from Northwestern and Cornell University was published by the journal ACS Central Science.

To demonstrate the new material’s capabilities, the researchers built a coin-cell battery prototype device capable of powering a light-emitting diode for 30 seconds.

The material has outstanding stability, capable of 10,000 charge/discharge cycles, the researchers report. They also performed extensive additional experiments to understand how the COF and the conducting polymer, called poly(3,4-ethylenedioxythiophene) or PEDOT, work together to store electrical energy.

Dichtel and his team made the material on an electrode surface. Two organic molecules self-assembled and condensed into a honeycomb-like grid, one 2-D layer stacked on top of the other. Into the grid’s holes, or pores, the researchers deposited the conducting polymer.

Each pore is only 2.3 nanometers wide, but the COF is full of these useful pores, creating a lot of surface area in a very small space. A small amount of the fluffy COF powder, just enough to fill a shot glass and weighing the same as a dollar bill, has the surface area of an Olympic swimming pool.

The modified COF showed a dramatic improvement in its ability to both store energy and to rapidly charge and discharge the device. The material can store roughly 10 times more electrical energy than the unmodified COF, and it can get the electrical charge in and out of the device 10 to 15 times faster.

“It was pretty amazing to see this performance gain,” Dichtel said. “This research will guide us as we investigate other modified COFs and work to find the best materials for creating new electrical energy storage devices.”

Toshiba America Electronic Components, Inc. (TAEC) today announced a new lineup of ultra-efficient, high-speed, high-voltage MOSFETs for switching voltage regulator designs. Available with 800V and 900V ratings, the four N-channel devices (TK4A80E, TK5A80E, TK3A90E, TK5A90E) are targeted to applications including flyback converters in LED lighting, supplementary power supplies and other circuits that require current switching below 5.0A.

The new enhancement mode MOSFETs are based on Toshiba’s π-MOS VIII (Pi-MOS-8), the company’s eighth generation planar semiconductor process, which combines high levels of cell integration with optimized cell design. This technology supports reduced gate charge and capacitance compared to prior generations, without losing the benefits of low RDS(ON).

These MOSFETs represent low-current supplements to Toshiba’s existing DTMOS IV line-up of 800V superjunction DTMOS IV devices. The 2.5A TK3A90E and 4.5A TK5A90E feature VDSS ratings of 900V and have typical RDS(ON)ratings of 3.7Ω and 2.5Ω, respectively. Both the 4.0A TK4A80E and 5.0A TK5A80E devices offer VDSS ratings of 800V with typical RDS(ON) ratings of 2.8Ω and 1.9Ω, respectively.

Toshiba’s new high-voltage MOSFETs offer an ultra-low maximum leakage current of only 10μA (VDS = 640V for the 800V device; VDS = 720V for the 900V device) and a gate threshold voltage range of 2.5V to 4.0V. All of the devices are supplied in a standard TO-220SIS form factor.

The upconversion of photons allows for a more efficient use of light: Two photons are converted into a single photon having higher energy. Researchers at KIT now showed for the first time that the inner interfaces between surface-mounted metal-organic frameworks (SURMOFs) are suited perfectly for this purpose – they turned green light blue. The result, which is now being published in the Advanced Materialsjournal, opens up new opportunities for optoelectronic applications such as solar cells or LEDs. (DOI: 10.1002/adma.201601718)

Photon upconversion: energy transfer between the molecules is based on electron exchange (Dexter electron transfer). Credit: Illustration: Michael Oldenburg

Photon upconversion: energy transfer between the molecules is based on electron exchange (Dexter electron transfer). Credit: Illustration: Michael Oldenburg

Metal-organic frameworks (MOFs) are highly ordered molecular systems that consist of metallic clusters and organic ligands. At the Institute of Functional Interfaces (IFG) of KIT, researchers developed MOFs that grow epitaxially on the surfaces of substrates. These SURMOFs (surface-mounted metal-organic frameworks) can be produced from various materials and be customized using different pore sizes and chemical functionalities so that they are suited for a broad range of applications, e.g. for sensors, catalysts, diaphragms, in medical device technology or as intelligent storage elements.

Another field of application is optoelectronics, i.e. components that are capable of converting light into electrical energy or vice versa. Many of these components work on the basis of semiconductors. “The SURMOFs combine the advantages of organic and anorganic semiconductors,” Professor Christof Wöll, Director of IFG, explains. “They feature chemical diversity and crystallinity, allowing us to create ordered heterostructures.” In many optoelectronic components, a so-called heterojunction – this is an interfacing layer between two different semiconductor materials – controls the energy transfer between the various excited states. Researches of the KIT Institute of Microstructure Technology (IMT) now created a new piggyback SURMOF in which a second SURMOF grew epitaxially, i.e. layer by layer, on a first one. At this heterojunction, it was possible to achieve photon upconversion, transforming two low-energy photons into a single photon with higher energy, by virtually fusing them together. “This process turns green light blue. Blue light has a shorter wavelength and yields more energy. This is very important for photovoltaics applications,” explains Professor Bryce Richards, Director of IMT. The scientists are presenting their work in Advanced Materials, one of the leading journals for materials science.

The photon upconversion process shown by the Karlsruhe researchers is based on the so-called triplet-triplet annihilation. Two molecules are involved: a sensitizer molecule that absorbs photons and creates triplet excited states, and an emitter molecule that takes over the triplet excited states and, by using triplet-triplet annihilation, sends out a photon that yields a higher energy than the photons that were originally absorbed. “The challenge was to create this process as efficiently as possible,” explains Dr. Ian Howard, leader of a junior research group at IMT. “We matched the sensitizer and emitter layers in a way to obtain a low conversion threshold and a higher light efficiency at the same time.”

Since the triplet transfer is based on the exchange of electrons, the photon upconversion process revealed by the researchers includes an electron transfer across the interface between the two SURMOFs. This suggests the assumption that SURMOF-SURMOF heterojunctions are suitable for many optoelectronic applications such as LEDs and solar cells. One of the limitations for the efficiency of today’s solar cells is due to the fact that they can only use photons with a certain minimum energy for electric power generation. By using upconversion, photovoltaic systems could become much more efficient.

ams AG (SIX: AMS), a provider of high performance sensors and analog ICs, has launched the smallest ever optical sensor module that delivers a combination of colour (RGB), ambient light and proximity sensing, providing OEMs with design flexibility and the ability to provide a better display viewing experience.

The TMD3700 footprint, at 4.00 x 1.75mm, is the smallest footprint available in the market, and with height of 1.00mm, its low-profile is ideal for next-generation mobile phones with extremely tight layout and mechanical design constraints. Its wide 45 degree field-of-view, ambient light sensing accuracy of +/-10% and operating range of 200mlux to 60Klux behind dark glass enable smartphones to measure the surrounding light environment and automatically adjust display colour and brightness for optimal viewing.

The TMD3700 colour sensor channels each have UV and IR blocking filters and a dedicated converter allowing simultaneous data capture necessary for accurate measurements. The combination of photopic colour and ambient light sensing enables smartphones to perform real-time adjustment of the display properties, such as white point, colour gamut and colour saturation, to achieve the best visual colour accuracy.

The TMD3700 features allow dynamic elimination of both electrical and optical crosstalk producing reliable proximity detection, a function used by smartphone manufacturers to disable the touchscreen display when it is held close to the user’s face. In addition, the module’s integrated IR LED is calibrated for maximum performance and consistent operation.

“Smartphone OEMs are continually condensing their product profiles while seeking ways to improve display performance for the best visual appeal. The availability of the TM3700 light sensing and proximity detection performance in a compact package enables innovative display management for today’s space-constrained smartphones,” said Darrell Benke, Strategic Program Director for Advanced Optical Solutions at ams.

Researchers at the University of Illinois at Urbana Champaign have developed a new method for making brighter and more efficient green light-emitting diodes (LEDs). Using an industry-standard semiconductor growth technique, they have created gallium nitride (GaN) cubic crystals grown on a silicon substrate that are capable of producing powerful green light for advanced solid-state lighting.

A new method of cubic phase synthesis: Hexagonal-to-cubic phase transformation. The scale bars represent 100 nm in all images. (a) Cross sectional and (b) Top-view SEM images of cubic GaN grown on U-grooved Si(100). (c) Cross sectional and (d) Top-view EBSD images of cubic GaN grown on U-grooved Si(100), showing cubic GaN in blue, and hexagonal GaN in red. Credit: University of Illinois

A new method of cubic phase synthesis: Hexagonal-to-cubic phase transformation. The scale bars represent 100 nm in all images. (a) Cross sectional and (b) Top-view SEM images of cubic GaN grown on U-grooved Si(100). (c) Cross sectional and (d) Top-view EBSD images of cubic GaN grown on U-grooved Si(100), showing cubic GaN in blue, and hexagonal GaN in red. Credit: University of Illinois

“This work is very revolutionary as it paves the way for novel green wavelength emitters that can target advanced solid-state lighting on a scalable CMOS-silicon platform by exploiting the new material, cubic gallium nitride,” said Can Bayram, an assistant professor of electrical and computer engineering at Illinois who first began investigating this material while at IBM T.J. Watson Research Center several years ago.

“The union of solid-state lighting with sensing (e.g. detection) and networking (e.g. communication) to enable smart (i.e. responsive and adaptive) visible lighting, is further poised to revolutionize how we utilize light. And CMOS-compatible LEDs can facilitate fast, efficient, low-power, and multi-functional technology solutions with less of a footprint and at an ever more affordable device price point for these applications.”

Typically, GaN forms in one of two crystal structures: hexagonal or cubic. Hexagonal GaN is thermodynamically stable and is by far the more conventional form of the semiconductor. However, hexagonal GaN is prone to a phenomenon known as polarization, where an internal electric field separates the negatively charged electrons and positively charged holes, preventing them from combining, which, in turn, diminishes the light output efficiency.

Until now, the only way researchers were able to make cubic GaN was to use molecular beam epitaxy, a very expensive and slow crystal growth method when compared to the widely used metal-organic chemical vapor deposition (MOCVD) method that Bayram used.

Bayram and his graduate student Richard Liu made the cubic GaN by using lithography and isotropic etching to create a U-shaped groove on Si (100). This non-conducting layer essentially served as a boundary that shapes the hexagonal material into cubic form.

“Our cubic GaN does not have an internal electric field that separates the charge carriers–the holes and electrons,” explained Liu. “So, they can overlap and when that happens, the electrons and holes combine faster to produce light.”

Ultimately, Bayram and Liu believe their cubic GaN method may lead to LEDs free from the “droop” phenomenon that has plagued the LED industry for years. For green, blue, or ultra-violet LEDs, their light-emission efficiency declines as more current is injected, which is characterized as “droop.”

“Our work suggests polarization plays an important role in the droop, pushing the electrons and holes away from each other, particularly under low-injection current densities,” said Liu, who was the first author of the paper, “”Maximizing Cubic Phase Gallium Nitride Surface Coverage on Nano-patterned Silicon (100)”, appearing Applied Physics Letters.

Having better performing green LEDs will open up new avenues for LEDs in general solid-state lighting. For example, these LEDs will provide energy savings by generating white light through a color mixing approach. Other advanced applications include ultra-parallel LED connectivity through phosphor-free green LEDs, underwater communications, and biotechnology such as optogenetics and migraine treatment.

Enhanced green LEDs aren’t the only application for Bayram’s cubic GaN, which could someday replace silicon to make power electronic devices found in laptop power adapters and electronic substations, and it could replace mercury lamps to make ultra-violet LEDs that disinfect water.

Researchers from North Carolina State University and the U.S. Army Research Office have developed a way to integrate novel functional materials onto a computer chip, allowing the creation of new smart devices and systems.

The novel functional materials are oxides, including several types of materials that, until now, could not be integrated onto silicon chips: multiferroic materials, which have both ferroelectric and ferromagnetic properties; topological insulators, which act as insulators in bulk but have conductive properties on their surface; and novel ferroelectric materials. These materials are thought to hold promise for applications including sensors, non-volatile computer memory and microelectromechanical systems, which are better known as MEMS.

“These novel oxides are normally grown on materials that are not compatible with computing devices,” says Jay Narayan, the John C. Fan Distinguished Chair Professor of Materials Science and Engineering at NC State and co-author of a paper describing the work. “We are now able to integrate these materials onto a silicon chip, allowing us to incorporate their functions into electronic devices.”

The approach developed by the researchers allows them to integrate the materials onto two platforms, both of which are compatible with silicon: a titanium nitride platform, for use with nitride-based electronics; and yttria-stabilized zirconia, for use with oxide-based electronics.

Specifically, the researchers developed a suite of thin films that serve as a buffer, connecting the silicon chip to the relevant novel materials. The exact combination of thin films varies, depending on which novel materials are being used.

For example, if using multiferroic materials, researchers use a combination of four different thin films: titanium nitride, magnesium oxide, strontium oxide and lanthanum strontium manganese oxide. But for topological insulators, they would use a combination of only two thin films: magnesium oxide and titanium nitride.

These thin film buffers align with the planes of the crystalline structure in the novel oxide materials, as well as with the planes of the underlying substrate – effectively serving as a communicating layer between the materials.

This approach, called thin film epitaxy, is based on the concept of domain-matching epitaxy, and was first proposed by Narayan in a 2003 paper.

“Integrating these novel materials onto silicon chips makes many things possible,” Narayan says. “For example, this allows us to sense or collect data; to manipulate that data; and to calculate a response – all on one compact chip. This makes for faster, more efficient, lighter devices.”

Another possible application, Narayan says, is the creation of LEDs on silicon chips, to make “smart lights.” Currently, LEDs are made using sapphire substrates, which aren’t directly compatible with computing devices.

“We’ve already patented this integration technology, and are currently looking for industry partners to license it,” Narayan says.

Samsung Electronics Co., Ltd. announced today that it has introduced “Fx-CSP,” a line-up of LED packages which features chip-scale packaging and flexible circuit board technology, for use in automotive lighting applications.

New Samsung Fx-CSP automotive LED packages (Graphic: Business Wire)

New Samsung Fx-CSP automotive LED packages (Graphic: Business Wire)

“Our new Fx-CSP line-up will bring greater design flexibility and cost competitiveness to the automotive lighting industry,” said Jacob Tarn, executive vice president, LED Business Team, Samsung Electronics. He added that, “We will continue to introduce innovative LED products and technologies, such as multi-chip array technology, that can play a key role in the growth of the automotive LED lighting industry.”

Samsung’s new Fx-CSP provides an advanced combination of chip-scale packaging and flexible circuit board technology, which together enable more compact chip sizing and a higher degree of reliability. The use of a flexible circuit board also enables more heat to dissipate, which leads to lower resistance and brings about a greater degree of lumen-per-watt efficiency than using a ceramic board.

In addition, the new Samsung automotive LED line-up allows car designers to use a variety of chip arrangements such as a single chip, a 1 by 4, or a 2 by 6 multi-chip arrangement to suit different lighting configurations. The Fx-CSP line-up can be widely used in automotive lighting applications that include position lamps and daytime running lamps as well as headlamps that require higher luminous flux and reliability than other automotive lamps.

The Fx-CSP line-up consists of single packages, Fx1M and Fx1L, with 1-3 watts each, as well as packages with a 14W high voltage array, Fx4 and a 40W high voltage array, Fx2x6. The variation in wattage levels allows Samsung LED lighting packages to work well with a wide range of exterior automotive lighting.

By adding the new Fx-CSP line-up to its existing mid-power and high-power automotive LED component line-ups, Samsung now provides a highly competitive family of automotive lighting components.

Samsung’s new Fx-CSP LED line-up was recently selected for a compact car headlamp project from one of the major global automotive manufacturers.

Samsung plans to introduce more CSP technology-based LED components such as the new Fx-CSP line-up for automotive lighting, later this year.