Category Archives: Flexible Displays

London, UK and San Jose, California – Dialog Semiconductor and Atmel Corporation announced today that Dialog has agreed to acquire Atmel in a cash and stock transaction for total consideration of approximately $4.6 billion. The acquisition creates a global leader in both Power Management (defined as power management solutions for mobile platforms including smartphones, tablets, portable PCs and wearable-type devices) and Embedded Processing solutions. The transaction results in a company that supports Mobile Power, IoT and Automotive customers. The combined company will address a market opportunity of approximately $20 billion by 2019.

Dialog will complement its position in Power Management ICs with a portfolio of proprietary and ARM (R) based Microcontrollers in addition to high performance ICs for Connectivity, Touch and Security. Dialog will also leverage Atmel’s established sales channels to diversify its customer base. Through realized synergies, the combination could deliver an improved operating model and enable new revenue growth opportunities.

“The rationale for the transaction we are proposing today is clear – and the potential this combination holds is exciting. By bringing together our technologies, world-class talent and broad distribution channels we will create a new, powerful force in the semiconductor space. Our new, enlarged company will be a diversified, high-growth market leader in Mobile Power, IoT and Automotive. We firmly believe that by combining Power Management, Microcontrollers, Connectivity and Security technologies, we will create a strong platform for innovation and growth in the large and attractive market segments we serve. This is an important and proud milestone in the evolution of our Dialog story,” said Jalal Bagherli, Dialog Chief Executive Officer.

“This transaction combines two successful companies and will create significant value for Atmel and Dialog shareholders, customers and employees. Adding Dialog’s world-class capabilities in Power Management with Atmel’s keen focus on Microcontrollers, Connectivity and Security will enable Dialog to more effectively target high-growth applications within the Mobile, IoT and Automotive markets,” said Steven Laub, Atmel President and Chief Executive Officer.

The transaction is expected to close in the first quarter of the 2016 calendar year. In 2017, the first full year following closing, the transaction is expected to be accretive to Dialog’s underlying earnings. Dialog anticipates achieving projected annual cost savings of $150 million within two years. The purchase price implies a total equity value for Atmel of approximately $4.6 billion and a total enterprise value of approximately $4.4 billion after deduction of Atmel’s net cash. Dialog expects to continue to have a strong cash flow generation profile and have the ability to substantially pay down the transaction debt approximately three years after closing.

The transaction has been unanimously approved by the boards of directors of both companies and is subject to regulatory approvals in various jurisdictions and customary closing conditions, as well as the approval of Dialog and Atmel shareholders. Jalal Bagherli will continue to be the Chief Executive Officer and Executive Board Director of Dialog. Two members of Atmel’s existing Board will join Dialog’s Board following closing. The transaction is not subject to a financing condition.

With a recent sharp rise in the number of patent applications for flexible display technologies, the market for various types of flexible displays is expected to broaden. According to IHS, 312 patents for flexible displays were filed with the United States Patent and Trademark Office in 2014; user-interface technology was the most active sector for patent applications. Flexible displays accounted for 62 percent of US display patent applications last year.

“Flexible displays are next-generation display panels fabricated on a paper-thin and flexible substrate, so that they can be bent and rolled without damage,” said Ian Lim, Senior Analyst of Intellectual Property for IHS Technology. “These types of displays, which lend themselves to far wider applications than conventional rigid displays, are projected to create an entirely new display market and replace existing non-flexible display solutions.”

Based on the latest information from the IHS Flexible Display Patent Report–which covers patents related to flexible displays issued in the US, in 2014, focusing on materials, manufacturing technology and applied devices–Samsung Electronics filed half of all new flexible display patents in the United States, followed by LG Electronics at 17 percent. Most of these patent applications focus on preventing image degradation, reducing device distortion and providing a range of user interfaces for bendable and foldable displays. Patents on parts and manufacturing technologies that primarily focus on the use of polyimide flexible substrates and metal nanowire in organic light-emitting diode (OLED) displays were also popular.

“Patents for flexible display device technologies outnumber those for flexible display parts and manufacturing technologies in recent patents, indicating that the flexible display market is entering a period of maturing growth,” Lim said. “As manufacturer requirements for flexible displays grow, battles to acquire relevant patents will only become fiercer.”

Flexible_display_patent_chart

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.

Electronic materials play a key role in touch panel technologies, such as new flexible touch technologies. Equally application know-how plays a vital part in the success of the new material to be used in device manufacture.

Together with ITRI, Taiwan, Heraeus, demonstrated the integration of Clevios conductive polymer based touch panel with AM OLED technology in a highly flexible device. The device was prepared using Clevios PEDOT conductive polymer material (formulated by EOC, Taiwan) patterned on ITRI’s FlexUp substrate. Solution processable and printable Clevios PEDOT: PSS is used as the transparent electrode in this device. In the project a 7 inch flexible Touch Panel / AM OLED device was produced.

Heraeus has been collaborating with ITRI since 2013.

“In this latest development project with ITRI, we have produced a reliable, flexible, advanced touch panel and integrated it with an AM OLED display, opening up new possibilities in flexible, foldable and wearable technologies” said Dr. Stephan Kirchmeyer, Global Marketing Director for the Display & Semiconductor Business at Heraeus. Dr. Janglin Chen, Vice President and General Director of ITRI’s Display Technology Center added, “The co-operation with Heraeus has shown the options for touch panel makers are broader than just metallic based ITO-alternatives.”

Further projects with the ITRI Group and Heraeus in the application of displays are ongoing. The touch sensor electrodes are based on a Clevios PEDOT. The experts at ITRI subsequently patterned the film using Heraeus invisible etch technology. A key element is flexibility which was tested 10,000 times at a bending radius of 5mm. The touch panel is laminated on the AM OLED display. The final product has 5 interactive functions within the display including touch controllable zoom in/out and rotation functions.

The Clevios PEDOT:PSS range from the Display & Semiconductor Business Unit of Heraeus consists of materials for antistatic through to highly conductive applications. Materials are modified for their application method, usually printing or coating, and for their end application requirements. Typically Clevios coatings can reach 100 -250 Ohm/sq. at a transparency of 90 percent (excluding substrate film). Clevios is increasingly finding applications in touch panels and sensors, as well as OLEDs, organic solar cells and security coatings.

The U.S. Department of Defense (DoD) today awarded FlexTech Alliance a Cooperative Agreement to establish and manage a Manufacturing Innovation Institute (MII) for Flexible Hybrid Electronics (FHE MII). The award is for $75 million in federal funding over a five-year period and is being matched by more than $96 million in cost sharing from non-federal sources, including the City of San Jose, private companies, universities, several U.S. states, and not-for-profit organizations. FlexTech Alliance’s winning proposal results in the first of seven MIIs to be headquartered on the West Coast. The DoD’s Manufacturing Technology Program Office (ManTech) oversees the MIIs.

U.S. Secretary of Defense, Ashton Carter, delivered today’s announcement at National Full-Scale Aerodynamics Complex at NASA’s Ames Research Center in Moffett Field. FlexTech Alliance, a research consortium and trade association, successfully proposed a San Jose-based hub and node approach to create the FHE MII, which comprises 96 companies, 11 laboratories and non-profits, 42 universities, and 14 state and regional organizations.

The Institute’s activities will benefit a wide array of markets beyond defense, including automotive, communications, consumer electronics, medical devices, health care, transportation and logistics, and agriculture. While the Institute will be headquartered in San Jose, existing nodes around the country already have in place an infrastructure ready to solve some of the known manufacturing challenges. The Institute will distribute R&D funds via competitively-bid project calls. Industry-generated technology roadmaps will drive project calls, timelines and investments.

Additionally, education and training in FHE manufacturing will be emphasized in order to expand the available workforce. A “Flex School” concept will be developed through partnerships with community colleges, teaching and research universities, trade associations, and professional societies.

Michael Ciesinski, president and CEO of FlexTech Alliance, said, “FlexTech is privileged to accept this award from the Defense Department to stand up and lead the FHE MII. Our partners collaborated on a superb proposal that links a national hub in San Jose to a network of centers of excellence throughout the U.S. We are excited by the FHE manufacturing challenge and eager to get operations underway.”

Flexible hybrid electronics, an emerging manufacturing capability, enables the integration of thin silicon electronic devices, sensing elements, communications, and power on non-traditional flexible substrates. FHE has the potential to re-shape entire industries, from the electronic wearable devices market, to medical health monitoring systems, to the ubiquitous sensing of the world around us – also known as the Internet of Things. To be successful, the Institute will need to engage aspects of the integrated circuit (IC) industry, the graphics printing industry, and the electronic assembly/packaging industry.

FlexTech

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The new institute is part of the National Network for Manufacturing Innovation program (NNMI). The FHE MII is the seventh MII announced—the fifth under DOD management. The NNMI program is an initiative of the Obama Administration to support advanced manufacturing in the U.S. Each institute is part of a growing network dedicated to securing U.S. leadership in the emerging technologies required to win the next generation of advanced manufacturing.  Bridging the gap between applied research and large-scale product manufacturing, the institutes bring together companies, universities, other academic and training institutions, and Federal agencies to co-invest in technology areas that benefit the nation’s commercial and national defense interests.

“The intent of the MII is to draw in the country’s ‘best of the best’ scientists, engineers, manufacturing experts and business development professionals in the field of flexible hybrid electronics,” stated Dr. Malcolm Thompson, Executive Director-designate of the Institute. Under the FlexTech proposal, the Hub provides overall program direction, is the integrator of components, creates prototypes, and matures manufacturing readiness levels (MRLs). “Fast start” projects for equipment, materials, devices and other vital components will make use of existing node facilities and key personnel from around the country.

Manufacturing provides well-paying job opportunities at a range of educational levels in occupations spanning engineering, production, logistics and sales. Commenting on the Institute’s local impact, San Jose Mayor Sam Liccardo noted, “San Jose ranks number one in the nation for Advanced Technology Industries, and is in the top two for Advanced Manufacturing.  Here in Silicon Valley, our extensive advanced manufacturing capability is essential for new product innovation across a range of growth areas—including wearable electronics, medical devices, connected vehicles, and clean tech.  The Manufacturing Innovation Institute for Flexible Hybrid Electronics will accelerate growth of companies and good jobs in San Jose. This decision affirms San Jose’s role as global hub for innovation advancing the Internet of Things.”

To complement the San Jose hub, key technology nodes will be linked and include IC thinning, system design and fabrication, integration and assembly, and FHE applications. Several regional nodes have been recognized and more are expected.  Those currently aligned to the institute are centers and educational institutions throughout California, along with Alabama, Arizona, Arkansas, Connecticut, Georgia, Indiana, Massachusetts, Michigan, New York, North Dakota, Ohio and Texas.

Congressman Mike Honda (D-17) said, “Congratulations to the FlexTech team and Silicon Valley for being selected as the latest Manufacturing Innovation Institute.  As the epicenter of American innovation, Silicon Valley is uniquely poised to be the leader in advanced manufacturing. Headquartering this Flexible Hybrid Electronics hub in San Jose ensures that the best of Silicon Valley’s tremendous academic, commercial, industrial, public, and labor resources are available to bridge the technology transfer gap and develop this emerging, game-changing technology as it reshapes the electronics industry and brings good-paying, middle-class manufacturing jobs to the Bay Area.”

FlexTech Alliance is an industry association focused on growth, profitability, and success throughout the manufacturing and distribution chain of flexible, printed electronics, and displays. By facilitating collaboration between and among industry, government, and academia, FlexTech Alliance develops solutions for advancing these technologies from R&D to commercialization.

In 2020, flexible barrier manufacturing for flexible electronic devices such as displays will be a market worth more than US$184 million, according to IDTechEx Research. That equates to 3.8 million square meters of flexible barrier films for electronics.

Although multilayer approaches – usually organic and inorganic layers – have been the most popular solution for flexible encapsulation so far, there is significant development work with solutions based on single layer approaches such as flexible glass or atomic layer deposition (ALD) which could, in later years, capture part of the market. The table below, compiled by IDTechEx analysts shows some of the characteristics of flexible glass and ALD films as developers are looking to bring them to market.

Table 1. ALD and flexible glass metrics and commercialization status for Beneq, Lotus and Corning

Company Name  WVTR (gr/sq.m./day Deposition Technique Material Commercialization Status – Strategy
Beneq Can reach
10-6 		 Batch ALD. Also developing roll 2 Roll ALD. Proprietary Aluminium Oxide/Titanium Oxide nanolaminate Beneq supplies coating equipment
Lotus Can reach
10-6 		 Roll 2 Roll ALD Proprietary homogeneous mixture” of Aluminium Oxide/Titanium Oxide layers Lotus follows a licensing business model and is patenting Plasma Enabled Oxygen Radical Decomposition process so as to enable faster deposition rates
Corning Perfect sealing from water vapour/oxygen Down drawing Thin glass (less than 100 μm) Available in rolls and sheets, in sample volumes

Source: IDTechEx report “Barrier Layers for Flexible Electronics 2015-2025” www.IDTechEx.com/barrier

Flexible glass: current status, outlook and challenges

Flexible glass is a significant technical achievement, yet IDTechEx Research believes that it will not be the solution of choice for encapsulation of flexible electronics in the short to medium term, for multiple reasons.

In spite of the marketing spin given by the manufacturers, glass is inherently a fragile material and requires specialized handling and processing. While plastic materials can also be damaged, there is an important difference between the two: damage of barriers on plastic can lead to the failure of a specific part, however, shattering of glass, even if protective sheets are used, leads to particle contamination on the defect line able to affect multiple parts.

Inherent fragility of flexible glass makes sheet edges critical. All suppliers propose protective tabs to reduce the problem. However, any other particle on the processing equipment could also become a focal point of stress and lead to shattering of the glass sheet or web.

A strong point of traditional glass encapsulation (especially for top emission devices) has been its ability to form truly hermetic packaging by using glass frit and laser sealing. This advantage may not be transferable to flexible glass where glass-to-glass sealing may be very problematic and difficult because points of stress and relative twisting of the two sheets must be avoided in the laser firing of the frit. It may be that flexible glass has to be used in combination with adhesives (and desiccants).

Flexibility is another issue. Although glass is very flexible if flexed along a well-defined axis, it can be poor at tolerating any stress out of axis, so much so that twisting the sheet may lead to fracture. This is true with or without protective film applied to the glass. Extreme flexibility (r< 2-3 mm) may also be a problem. Data that has been shown would put the flexibility limit around r= 2.5 cm. Consequently, flexible glass as an encapsulant superstrate or substrate may be good for conformal applications, but for truly flexible applications there seem to be several challenges to be overcome.

Flexible glass makers are also waiting for equipment providers to make appropriate equipment to handle the flexible glass in manufacturing, another bottle neck.

Future opportunities for flexible glass

The thermal stability of flexible glass makes it the best choice as substrate for back-planes of high-resolution high-end large displays. Glass enables improved resolution and good registration between layers during processing compared to plastic substrates like PET, PEN, and PI. However, IDTechEx analysts and other affiliate experts have only seen results with metal oxide backplanes only so far (Tprocess < 350 C), none with LTPS backplanes (Tprocess < 450 C). If processability up to 450C is indeed possible, flexible glass would be a very good choice as a substrate for flexible AMOLED TV. Those devices are bottom emission (BE) AMOLED, normally have a metal foil as back encapsulant, a higher cost tolerance. Regarding R2R processing of flexible glass, it has demonstrated possible. Manufacturing by R2R will require specialized tools not differently than fabrication of barrier in R2R.

The multi-layer approach if correctly implemented on dedicated tools may have the potential to be low cost but an open question remains as to how low the defect density of barrier on foil can be. Consequently, it is an open question what the maximum size of displays that can be encapsulated with compatible yield can be. As it transpires from the discussion above, plastic engineered superstrate (=encapsulant foil) may be better for smaller devices (wearable, phone, tablets), while flexible glass may be better for TVs and in general larger displays.

Additionally, the smoothness of plastic films, even with smoothing layers, is not as good as glass (0.2 nm). This may be a problem for organic TFT backplanes. Finally optical transmission below 400nm require glass as substrate since PET and PEN have a cut off around 400 nm (PEN). IDTechEx does not see this as a critical limitation for general display applications (it may be for OPV).

Atomic layer deposition (ALD) present and future outlook/market share 

ALD is another flexible encapsulation technology receiving a lot of attention with several players currently developing solutions based on it. It seems like it is not a short-term solution, if it will ever be one as a stand-alone layer but ALD may be a solution in a multi-layer stack in combination with a sputtered or PECVD layer if it would be possible to find a good cost structure. Regarding the intrinsic properties of the material, ALD film deposited at low temperature (T<80 C) have a superior quality when tested at room temperature. A single ALD layer less-than 50 nm thick can perform better than thicker layers deposited by sputtering or PECVD.

However, the inherent stability of the films at higher temperature/humidity (e.g. 85C/85%RH) is a problem. If PE-CVD is used, ALD film stability improves, as well as for mixed oxides, but it is still an issue. A second problem comes with particles and substrates non-uniformity. Any defect may lead at an initial non-uniform nucleation that propagates into the growing film. Furthermore, loose particles on substrates may be partially covered, but because of the extreme thinness, the thin film does not have the mechanical strength to keep them in place under mechanical stress. Any mechanical stress leads to film fracture with consequent creation of an ingress path for moisture. That is why multilayer structures are necessary.

Deposition tools are in development from Lotus, Beneq, Encapsulix and others. Exploration at Samsung SDC with ALD films for TFE was very much advertised by Synos, but resulted in failure and any further evaluation was halted. ALD for barrier on foil has better results although there are doubts and hurdles in scaling up and reaching the deposition speed required for a cost effective process.

This is also one of the sessions at the Printed Electronics USA event, to be held on November 18-19 at Santa Clara, CA. See www.PrintedElectronicsUSA.com for full details.

Global consumers have lately become less interested in acquiring conventional notebooks with 15-inch displays, and they are instead shifting their spending to smaller product segments. In the first half of 2015, panel shipments in the 15-inch range (i.e., 15.0 inches to 15.9 inches) dropped 14 percent year over year, from 44.5 million to 38.4 million units, according to IHS Inc. (NYSE: IHS), a global source of critical information and insight. At the same time, driven by the popularity of Chromebook, notebook display shipments in the 11-inch range have grown from 8 million units to 11 million units.

Notebook_Displays_Chart

“Thanks to affordable prices, and a completed ecosystem with a host of hardware and app choices and a user-friendly cloud environment, Chromebook has expanded its customer base from small and medium-sized businesses and the education market to general users,” said Jason Hsu, supply chain senior analyst for IHS Technology. “The Chromebook sales region has also expanded from the United States to emerging countries, where more local brands are launching Chromebook product offerings. There are also more products set to debut in the 12-inch range, thanks to the success of the Microsoft Surface Pro 3 and rumors of Apple’s upcoming 12.9-inch tablets.”

According to the most recent IHS Notebook and Tablet Display Supply Chain Tracker, total notebook panel shipments to Lenovo and Hewlett-Packard fell 27 percent month over month from 6.4 million units in May to 4.7 million units in June, while overall set production increased by 13 percent from 5.4 million units to 6.1 million units. These two leading notebook PC brands have recently taken steps to regulate panel inventory, in order to guard against excess product pre-stocking.

“The currency depreciation in Euro zone and emerging counties earlier this year jeopardized consumer confidence and slowed the purchase of consumer electronics, including notebooks,” Hsu said. “Moreover, in April, Microsoft leaked the announcement of its new Windows 10 operating system. Despite Microsoft’s claims that a free upgrade to the new operating system would be available to Windows 8 users, many consumers still deferred purchases, which increased the brands’ set inventory. Notebook manufacturers could decide to lower set production in the third quarter, after the end market becomes sluggish in May and June.”

With notebook panel prices remaining very low, profitability has become an issue, and many panel makers are facing pressure to maintain fab loading and gain market share. “Panel cost structure has become crucial in the struggle to stay competitive,” Hsu said. “Continuous panel over-supply not only hurts profitability, but could also confuse the real panel market demand in the fourth quarter of 2015 and the first quarter of 2016. It’s time for panel makers to revise their production numbers, and curb capacity utilization, to keep pace with actual market demand.”

With screen sizes increasing, smartphones continue to lead total area demand in the cover glass market; however, as the markets for smartphones and tablets mature, cover glass industry revenue growth is declining from 39 percent year over year in 2013 to 11 percent in 2015. While the overall cover glass market growth is falling, increasing popularity of the Apple Watch is leading to growth in smart watch cover glass shipments, according to IHS Inc., a global source of critical information and insight.

“Although the average display size for tablets is increasing, simpler industrial design and weak device demand are causing average selling prices for cover glass to fall quickly,” according to Terry Yu, senior analyst for small and medium displays for IHS. “Cover glass makers are now pinning hopes on smart watches, as a way to shore up flagging revenue growth caused by the maturation of the smartphone and tablet segments.”

Smartphones are forecast to comprise more than half (55 percent) of all cover glass area demand in 2015, followed by tablet PCs. More complicated requirements for smartphone cover glass — including higher aluminosilicate glass penetration, more drilling holes and more ink layers — are causing average selling prices (ASPs) to rise faster than area demand; smartphone cover glass is therefore expected to make up 63 percent of revenues in 2015. By way of comparison, tablet cover glass is expected to reach 29 percent share of total area demand in 2015, but will only comprise 25 percent of all cover glass revenue, according to the most recent Touch Panel Cover Glass Report from IHS.

cover_glass_data

Due largely to consumer demand for the Apple Watch, overall smart watch cover glass area demand is forecast to increase by five-fold in 2015, reaching 33,000 square meters. That is still only a tenth of a percent of total cover glass area shipments, as cover glasses for wearable devices are much smaller than those used in smartphones and tablet PCs. The slightly curved design known as 2.5D, along with higher sapphire glass penetration, will keep ASPs significantly higher, which will help smart watch cover glass revenue share rise to 3 percent of the total market in 2015.

Higher costs for aluminosilicate glass and sapphire glass can significantly affect total cover glass costs. In fact sapphire glass material costs in smart watches can be up to 12 times higher than the cost of aluminosilicate glass.

“Sapphire glass used in wearable devices commands a premium price, so growth in that area would help shore up industry revenues,” Yu said. “In addition, sapphire glass is already used in the traditional watch industry, which makes it easier to adopt by smart watch cover glass manufacturers.”

Note that this market analysis from IHS covers only front cover glass, and does not include glass used in rear covers, such as the Gorilla glass used on the back of the Galaxy S6.

Flexible displays are not only leading to sprawling applications and revolutionizing the display market, but they are also an increasingly important segment of overall display market revenues. In fact, flexible displays are expected to comprise 15 percent of the total display market revenue in 2024, according to a new report from IHS Inc. (NYSE: IHS), the leading global source of critical information and insight. As flexible organic light-emitting diode (OLED) production continues to improve, revenue from flexible display production will expand at a compound annual growth rate of 44 percent from 2014, to reach $23 billion in 2024, the IHS report says.

“Flexible OLED production yield has improved dramatically over the last few years, which could prompt panel manufacturers to ramp up flexible OLED production lines,” said Jerry Kang, principal analyst at IHS. “Market growth could also accelerate when flexible displays debut in foldable, rollable and stretchable forms.”

flex display revenue

Rugged, light, thin, non-brittle and portable flexible displays are feeding the market for various applications. For example, LG Electronics and Samsung Electronics have both applied flexible OLEDs to their flagship smartphones, to bolster sales in the slowing premium-smartphone market. The Apple Watch, which uses flexible display technology, has also added to the momentum of OLED in wearable devices. “Flexible display technology is not only gathering heated attention from electronics giants, but it is also stimulating startups to experiment with novel applications and innovations,” Kang said.

Flexing graphene may be the most basic way to control its electrical properties, according to calculations by theoretical physicists at Rice University and in Russia.

The Rice lab of Boris Yakobson in collaboration with researchers in Moscow found the effect is pronounced and predictable in nanocones and should apply equally to other forms of graphene.

The researchers discovered it may be possible to access what they call an electronic flexoelectric effect in which the electronic properties of a sheet of graphene can be manipulated simply by twisting it a certain way.

The work will be of interest to those considering graphene elements in flexible touchscreens or memories that store bits by controlling electric dipole moments of carbon atoms, the researchers said.

Perfect graphene – an atom-thick sheet of carbon – is a conductor, as its atoms’ electrical charges balance each other out across the plane. But curvature in graphene compresses the electron clouds of the bonds on the concave side and stretches them on the convex side, thus altering their electric dipole moments, the characteristic that controls how polarized atoms interact with external electric fields.

The researchers who published their results this month in the American Chemical Society’s Journal of Physical Chemistry Letters discovered they could calculate the flexoelectric effect of graphene rolled into a cone of any size and length.

The researchers used density functional theory to compute dipole moments for individual atoms in a graphene lattice and then figure out their cumulative effect. They suggested their technique could be used to calculate the effect for graphene in other more complex shapes, like wrinkled sheets or distorted fullerenes, several of which they also analyzed.

“While the dipole moment is zero for flat graphene or cylindrical nanotubes, in between there is a family of cones, actually produced in laboratories, whose dipole moments are significant and scale linearly with cone length,” Yakobson said.

Carbon nanotubes, seamless cylinders of graphene, do not display a total dipole moment, he said. While not zero, the vector-induced moments cancel each other out.

That’s not so with a cone, in which the balance of positive and negative charges differ from one atom to the next, due to slightly different stresses on the bonds as the diameter changes. The researchers noted atoms along the edge also contribute electrically, but analyzing two cones docked edge-to-edge allowed them to cancel out, simplifying the calculations.

Yakobson sees potential uses for the newly found characteristic. “One possibly far-reaching characteristic is in the voltage drop across a curved sheet,” he said. “It can permit one to locally vary the work function and to engineer the band-structure stacking in bilayers or multiple layers by their bending. It may also allow the creation of partitions and cavities with varying electrochemical potential, more ‘acidic’ or ‘basic,’ depending on the curvature in the 3-D carbon architecture.”