David Savastano, Editor11.07.14
Touch screens and displays are important markets for flexible and printed electronics. Manufacturers are constantly seeking ways to make their displays and touch screens lighter, and one of the most sought-after goals is developing flexible screens.
Over the years, OLED (organic light emitting diode) displays have received much attention, both for their improved performance as well as the possibility of producing them through printing and other high-production processes. OLEDs have become a popular technology for mobile phone touch screens, and are heading into the television market.
To meet the needs of their touch screen and display customers, materials suppliers are working on a number of innovations. These new products will likely drive the market.
Synaptics has become the leading developer of human interface solutions. Synaptics is both a customer and development partner for printed electronics inks, materials and processes, working closely with its OEM and ODM partners.
Bob Mackey, principal scientist for Synaptics, noted that Synaptics has touchscreens in almost all top tier flagship phones, including Samsung, Nokia, LG and Google. TouchPad, Synaptics’ flagship product, is integrated into a majority of today’s notebook computers.
“We are starting to see some demand for very thin displays that are somewhat flexible,” Mackey noted. “I have not yet seen much substantive commercial interest in fully flexible displays.”
Materials for Touch Screens and Displays
Whether it is conductive inks or solutions, manufacturers of materials for displays and touch screens are seeing interesting opportunities in the marketplace.
Stan Farnsworth, vice president of marketing for NovaCentrix, noted that because of the unique history of NovaCentrix, they are able to offer successful conductive ink products as well as the PulseForge photonic curing tools.
“We have recently begun shipping new formulations of the Metalon conductive inks developed specifically for inkjet application on non-porous, ITO-coated materials for display applications,” Farnsworth said. “These new inks have outstanding adhesion and conductivity, and they have excellent compatibility with piezo-inkjet printheads. The new inks include silver formulations as well as new carbon-based formulations. Beta-testing with confidential customers has been extremely successful.”
Sun Chemical Electronic Materials has a wide range of materials for the touch screen and display market.
“Sun Chemical Electronic Materials’ development efforts focus on several technologies,” said Roy Bjorlin, commercial director, Electronic Materials, Sun Chemical. “They include fine line PTF silver inks, laser abatable, photo image-able and inkjet nano silver. Other complementary materials include dielectrics and graphite-based conductors.”
Dr. Allen Reid of NANOGAP noted that NANOGAP has the ability to customize its nanofiber dispersion products to meet the needs of ink formulators.
“This includes controlling nanofiber dimensions and surface functionalization, in order to enhance conductive and optical properties as well as ink stability,” Dr. Reid added. “In addition, NANOGAP’s nanofiber dispersions exhibit long term room temperature stability. NANOGAP’s nanofiber products are produced by a unique catalytically controlled process, with granted process patents in the U.S. and Japan, giving a clear Freedom-to-Operate position. On the back of this technology, the company is now expanding, including developing manufacturing capability in the U.S.”
John Richard, global business director, DuPont OLED, said that DuPont has developed a set of soluble materials as well as a process to deposit them that is designed to dramatically lower the cost of producing large OLED displays such as televisions.
“Coating and printing techniques are inherently far more efficient in the consumption of expensive OLED materials than the current high-vacuum thermal evaporation technique while employing less expensive, more productive and scalable equipment,” Richard added. “The challenge the industry faces is to utilize those techniques and maintain the level of uniformity and device performance achievable with evaporation. Because the process is readily scalable, the fundamental cost structure of the printed OLED TV panels is anticipated to be far lower than achievable with an evaporation process and also lower than current LCD panel costs.”
Richard added that major OEMs are investing in capacity beyond pilot lines to achieve mass production for these types of displays as early as 2016.
Universal Display has been developing and commercializing phosphorescent OLED (PHOLED) technologies and materials that provide a range of benefits for today and tomorrow’s display and lighting applications.
“We believe that our proprietary UniversalPHOLED materials are a critical element to enable high performance, energy-efficient and longer lifetime OLED products,” said Darice Liu, director of investor relations and corporate communications for Universal Display. “This translates into reduced power consumption and less heat generation.”
Liu noted that Universal Display is currently working with 25 customers in the display and lighting markets.
“We have announced relationships with companies such as AU Optronics Corporation, BOE Technology, DuPont Displays, Inc., Innolux Corporation, Kaneka Corporation, Konica Minolta Technology Center, Inc., LG Display Co., Ltd., Lumiotec, Inc., Philips Technologie GmbH, Pioneer Corporation, Samsung Display Co., Ltd., Sony Corporation, and Tohoku Pioneer Corporation,” Liu added. “We believe our phosphorescent materials are in every energy-efficient OLED product in the market.”
Dr. Michael Cowin, head of product development for SmartKem Ltd., said that the company’s tru-FLEX technology offers production options from standard spin coat to inkjet and slot-dye techniques.
“The ability to manufacture at low temperature is key, as it allows manufacturers to use a wide range of cost effective stack materials and substrates while offering easier bond/de-bond and inter-layer alignment due to less expansion and contraction,” Dr. Cowin added.
Dr. Ron Lubianez, North American sales manager for Heraeus Precious Metals North America Conshohocken LLC’s Electronic Materials Division’s Display & Semiconductor Business Unit, noted that all of Heraeus’ materials for the active touch sensors in displays are based on PEDOT:PSS, which is then coated onto polyester (PET) films.
“We partner with companies that coat our material on PET films, such as Eastman Kodak in North America,” Lubianez added. “Kodak produces their PET film, then coats it in-line with the PEDOT:PSS conductive layer. PEDOT:PSS offers flexibility at lower cost, and can be processed without vacuum deposition or a sputter coater. It can be applied through traditional coating methods, without high capital costs.”
Sri Peruvemba, vice president of corporate marketing at large at Cambrios, said that Cambrios’ ClearOhm coating material is made from highly conductive, single-crystal silver nanowires, offering significantly higher optical and electrical performance than the incumbent material, indium tin oxide (ITO).
“ClearOhm material offers very high aspect ratio silver nanowires in a form that can be readily used to coat a variety of substrates, including roll-to-roll coating with high throughput, very thin and light form, enabling lower cost end products,” Peruvemba added.
Peruvemba added that Cambrios’ transparent conductors have gone into mass production and are used in products such as large touch panels, OLED, OPV devices and flexible displays. Cambrios’ customers and partners include TPK, Nissha, Hitachi, Okura, Shinwa, LG, 3M, UniDisplay, CNI, TouchWorks and more that have not been publicly announced. OEM customers include multiple products at Lenovo (19.5”, 23”, 27” AIO), Karbonn, NEC/NTT Docomo, GVision, Huawei, LG – for phones, tablets, monitors and AIO.
Challenges for Material Manufacturers
Mackey said that improved performance is a critical requirement.
“The performance of transparent conductors continues to improve,” Mackey said. “The incumbent ITO as well as relative newcomers such as Ag nanowire, carbon nanotubes (CNT), and metal mesh (M#) all must continue to improve to support better optics and faster design cycles.”
“The biggest challenge we are resolving for our customers continues to be enabling the use of high-performance materials on flexible or low-temperature substrates,” Farnsworth said. “We have active programs in place in the U.S., Asia, and Europe with display companies who are moving into production with materials solutions only possible using our PulseForge equipment.”
Bjorlin noted that Sun Chemical is working on a variety of challenges for its customers. “Fine line and faster process speeds are the greatest challenges that display and touch screen manufacturers are asking us to help them solve,” Bjorlin added.
“The market everyone seems to be chasing is ultra low haze for high end displays,” Dr. Reid said. “Our work in this area is all done under contract and NDA. With that said, there is still a sizable market for applications where some degree of haze is acceptable (electronic signature pads and lower end displays such as satellite navigation screens and home security systems), and some where it is even beneficial (solid state lighting). For these markets, we have low cost standard products available.”
Richard said there are a few areas that represent challenges for flexible display and touch screen producers.
“Flexible displays will largely be OLED based, and will require substrates that are very thermally and chemically stable, optically clear and defect-free,’ Richard said. “These are very demanding requirements for polymer-based materials. OLEDs also require protection from moisture and oxygen, necessitating reliable barrier layers and hermetic adhesives to bond layers together. If these are truly flexible, the transparent conductor materials also need to be able to flex without damage, a shortcoming of current materials. Each of these are technically challenging as well as difficult to achieve in a cost efficient manner.”
“Every customer and product has a unique set of technical specifications, so we develop specific technologies to help meet their ever changing product cycles,” said Liu. “It can be demanding, but with two decades of knowledge and experience, coupled with the largest R&D team dedicated to phosphorescent materials, we continue to deliver energy-efficient, high-performance, quality-assured OLED materials.”
“The increasing interest in flexible and wearable electronics gives way to demand for new technologies that enable smarter, more stylish and flexible devices,” Peruvemba added. “As this demand for flexible and high-performance displays rises, there is a greater need for silver nanowires. Unlike the incumbent material, silver nanowires make high performance and flexible displays possible. By using silver – the most conductive metal on the planet - device makers can produce touchscreens that are shatterproof, more rugged and lighter than current products.”
Outlook for Flexible and Printed Electronics Displays
Materials manufacturers agree that the display and touch screen markets are growing. Bjorlin said that the technologies for producing flexible/OLED displays are definitely moving forward.
“Certainly the advantages in brightness and image clarity will continue to drive applications,” Bjorlin added. “However, certain technologies, including protective coatings that will allow use in a broader range of applications, will still need improvement. Sun Chemical has a robust program in this area.”
“The outlook is positive,” Dr. Reid said. “Technical hurdles are being overcome and the market is growing.”
“We continue to be very bullish on the near-term and long-term outlook,” Farnsworth said. “Even though the market is still evaluating the role of flexible display end-products, there is significant technology pull from the market utilizing print methods on rigid/semi-rigid displays that is keeping our teams very busy here at NovaCentrix. At the same time we continue to see opportunities for new technology development, primarily around materials for inks and for improving the temperature and lifetime of OLED. The market is asking for progress in those areas, and we welcome the opportunity to work with groups specifically on those topics.”
“The flexible OLED market is exciting, and just in its nascent stage,” Liu said. “Currently, we are seeing initial curved products come out in display applications. Curved TVs and mobile electronics may one day become fully flexible, bendable and rollable, which could transform products and the way we view information.”
“Flexible and formable devices are also becoming a strong contender in the near term,” Peruvemba added. “Cambrios’ vision for the next era of display technology centers on 3D and flexible display such as curved car dashboards and wearable devices, like smart watches, that are flexible and comfortable. Also future applications of OPV and flexible solar panels will be able to wrap around large structures or be part of the sunroof in a car. From flexible OLED displays to e-paper displays, we are moving from the era of bulky, rectangular and fragile glass-based displays to an era of unique shaped, thin and conformable displays, and going three dimensional – and beyond – is going to be next big thing.”
For more information on materials for touch screens and displays, see the online version at www.printedelectronicsnow.com.
Over the years, OLED (organic light emitting diode) displays have received much attention, both for their improved performance as well as the possibility of producing them through printing and other high-production processes. OLEDs have become a popular technology for mobile phone touch screens, and are heading into the television market.
To meet the needs of their touch screen and display customers, materials suppliers are working on a number of innovations. These new products will likely drive the market.
Synaptics has become the leading developer of human interface solutions. Synaptics is both a customer and development partner for printed electronics inks, materials and processes, working closely with its OEM and ODM partners.
Bob Mackey, principal scientist for Synaptics, noted that Synaptics has touchscreens in almost all top tier flagship phones, including Samsung, Nokia, LG and Google. TouchPad, Synaptics’ flagship product, is integrated into a majority of today’s notebook computers.
“We are starting to see some demand for very thin displays that are somewhat flexible,” Mackey noted. “I have not yet seen much substantive commercial interest in fully flexible displays.”
Materials for Touch Screens and Displays
Whether it is conductive inks or solutions, manufacturers of materials for displays and touch screens are seeing interesting opportunities in the marketplace.
Stan Farnsworth, vice president of marketing for NovaCentrix, noted that because of the unique history of NovaCentrix, they are able to offer successful conductive ink products as well as the PulseForge photonic curing tools.
“We have recently begun shipping new formulations of the Metalon conductive inks developed specifically for inkjet application on non-porous, ITO-coated materials for display applications,” Farnsworth said. “These new inks have outstanding adhesion and conductivity, and they have excellent compatibility with piezo-inkjet printheads. The new inks include silver formulations as well as new carbon-based formulations. Beta-testing with confidential customers has been extremely successful.”
Sun Chemical Electronic Materials has a wide range of materials for the touch screen and display market.
“Sun Chemical Electronic Materials’ development efforts focus on several technologies,” said Roy Bjorlin, commercial director, Electronic Materials, Sun Chemical. “They include fine line PTF silver inks, laser abatable, photo image-able and inkjet nano silver. Other complementary materials include dielectrics and graphite-based conductors.”
Dr. Allen Reid of NANOGAP noted that NANOGAP has the ability to customize its nanofiber dispersion products to meet the needs of ink formulators.
“This includes controlling nanofiber dimensions and surface functionalization, in order to enhance conductive and optical properties as well as ink stability,” Dr. Reid added. “In addition, NANOGAP’s nanofiber dispersions exhibit long term room temperature stability. NANOGAP’s nanofiber products are produced by a unique catalytically controlled process, with granted process patents in the U.S. and Japan, giving a clear Freedom-to-Operate position. On the back of this technology, the company is now expanding, including developing manufacturing capability in the U.S.”
John Richard, global business director, DuPont OLED, said that DuPont has developed a set of soluble materials as well as a process to deposit them that is designed to dramatically lower the cost of producing large OLED displays such as televisions.
“Coating and printing techniques are inherently far more efficient in the consumption of expensive OLED materials than the current high-vacuum thermal evaporation technique while employing less expensive, more productive and scalable equipment,” Richard added. “The challenge the industry faces is to utilize those techniques and maintain the level of uniformity and device performance achievable with evaporation. Because the process is readily scalable, the fundamental cost structure of the printed OLED TV panels is anticipated to be far lower than achievable with an evaporation process and also lower than current LCD panel costs.”
Richard added that major OEMs are investing in capacity beyond pilot lines to achieve mass production for these types of displays as early as 2016.
Universal Display has been developing and commercializing phosphorescent OLED (PHOLED) technologies and materials that provide a range of benefits for today and tomorrow’s display and lighting applications.
“We believe that our proprietary UniversalPHOLED materials are a critical element to enable high performance, energy-efficient and longer lifetime OLED products,” said Darice Liu, director of investor relations and corporate communications for Universal Display. “This translates into reduced power consumption and less heat generation.”
Liu noted that Universal Display is currently working with 25 customers in the display and lighting markets.
“We have announced relationships with companies such as AU Optronics Corporation, BOE Technology, DuPont Displays, Inc., Innolux Corporation, Kaneka Corporation, Konica Minolta Technology Center, Inc., LG Display Co., Ltd., Lumiotec, Inc., Philips Technologie GmbH, Pioneer Corporation, Samsung Display Co., Ltd., Sony Corporation, and Tohoku Pioneer Corporation,” Liu added. “We believe our phosphorescent materials are in every energy-efficient OLED product in the market.”
Dr. Michael Cowin, head of product development for SmartKem Ltd., said that the company’s tru-FLEX technology offers production options from standard spin coat to inkjet and slot-dye techniques.
“The ability to manufacture at low temperature is key, as it allows manufacturers to use a wide range of cost effective stack materials and substrates while offering easier bond/de-bond and inter-layer alignment due to less expansion and contraction,” Dr. Cowin added.
Dr. Ron Lubianez, North American sales manager for Heraeus Precious Metals North America Conshohocken LLC’s Electronic Materials Division’s Display & Semiconductor Business Unit, noted that all of Heraeus’ materials for the active touch sensors in displays are based on PEDOT:PSS, which is then coated onto polyester (PET) films.
“We partner with companies that coat our material on PET films, such as Eastman Kodak in North America,” Lubianez added. “Kodak produces their PET film, then coats it in-line with the PEDOT:PSS conductive layer. PEDOT:PSS offers flexibility at lower cost, and can be processed without vacuum deposition or a sputter coater. It can be applied through traditional coating methods, without high capital costs.”
Sri Peruvemba, vice president of corporate marketing at large at Cambrios, said that Cambrios’ ClearOhm coating material is made from highly conductive, single-crystal silver nanowires, offering significantly higher optical and electrical performance than the incumbent material, indium tin oxide (ITO).
“ClearOhm material offers very high aspect ratio silver nanowires in a form that can be readily used to coat a variety of substrates, including roll-to-roll coating with high throughput, very thin and light form, enabling lower cost end products,” Peruvemba added.
Peruvemba added that Cambrios’ transparent conductors have gone into mass production and are used in products such as large touch panels, OLED, OPV devices and flexible displays. Cambrios’ customers and partners include TPK, Nissha, Hitachi, Okura, Shinwa, LG, 3M, UniDisplay, CNI, TouchWorks and more that have not been publicly announced. OEM customers include multiple products at Lenovo (19.5”, 23”, 27” AIO), Karbonn, NEC/NTT Docomo, GVision, Huawei, LG – for phones, tablets, monitors and AIO.
Challenges for Material Manufacturers
Mackey said that improved performance is a critical requirement.
“The performance of transparent conductors continues to improve,” Mackey said. “The incumbent ITO as well as relative newcomers such as Ag nanowire, carbon nanotubes (CNT), and metal mesh (M#) all must continue to improve to support better optics and faster design cycles.”
“The biggest challenge we are resolving for our customers continues to be enabling the use of high-performance materials on flexible or low-temperature substrates,” Farnsworth said. “We have active programs in place in the U.S., Asia, and Europe with display companies who are moving into production with materials solutions only possible using our PulseForge equipment.”
Bjorlin noted that Sun Chemical is working on a variety of challenges for its customers. “Fine line and faster process speeds are the greatest challenges that display and touch screen manufacturers are asking us to help them solve,” Bjorlin added.
“The market everyone seems to be chasing is ultra low haze for high end displays,” Dr. Reid said. “Our work in this area is all done under contract and NDA. With that said, there is still a sizable market for applications where some degree of haze is acceptable (electronic signature pads and lower end displays such as satellite navigation screens and home security systems), and some where it is even beneficial (solid state lighting). For these markets, we have low cost standard products available.”
Richard said there are a few areas that represent challenges for flexible display and touch screen producers.
“Flexible displays will largely be OLED based, and will require substrates that are very thermally and chemically stable, optically clear and defect-free,’ Richard said. “These are very demanding requirements for polymer-based materials. OLEDs also require protection from moisture and oxygen, necessitating reliable barrier layers and hermetic adhesives to bond layers together. If these are truly flexible, the transparent conductor materials also need to be able to flex without damage, a shortcoming of current materials. Each of these are technically challenging as well as difficult to achieve in a cost efficient manner.”
“Every customer and product has a unique set of technical specifications, so we develop specific technologies to help meet their ever changing product cycles,” said Liu. “It can be demanding, but with two decades of knowledge and experience, coupled with the largest R&D team dedicated to phosphorescent materials, we continue to deliver energy-efficient, high-performance, quality-assured OLED materials.”
“The increasing interest in flexible and wearable electronics gives way to demand for new technologies that enable smarter, more stylish and flexible devices,” Peruvemba added. “As this demand for flexible and high-performance displays rises, there is a greater need for silver nanowires. Unlike the incumbent material, silver nanowires make high performance and flexible displays possible. By using silver – the most conductive metal on the planet - device makers can produce touchscreens that are shatterproof, more rugged and lighter than current products.”
Outlook for Flexible and Printed Electronics Displays
Materials manufacturers agree that the display and touch screen markets are growing. Bjorlin said that the technologies for producing flexible/OLED displays are definitely moving forward.
“Certainly the advantages in brightness and image clarity will continue to drive applications,” Bjorlin added. “However, certain technologies, including protective coatings that will allow use in a broader range of applications, will still need improvement. Sun Chemical has a robust program in this area.”
“The outlook is positive,” Dr. Reid said. “Technical hurdles are being overcome and the market is growing.”
“We continue to be very bullish on the near-term and long-term outlook,” Farnsworth said. “Even though the market is still evaluating the role of flexible display end-products, there is significant technology pull from the market utilizing print methods on rigid/semi-rigid displays that is keeping our teams very busy here at NovaCentrix. At the same time we continue to see opportunities for new technology development, primarily around materials for inks and for improving the temperature and lifetime of OLED. The market is asking for progress in those areas, and we welcome the opportunity to work with groups specifically on those topics.”
“The flexible OLED market is exciting, and just in its nascent stage,” Liu said. “Currently, we are seeing initial curved products come out in display applications. Curved TVs and mobile electronics may one day become fully flexible, bendable and rollable, which could transform products and the way we view information.”
“Flexible and formable devices are also becoming a strong contender in the near term,” Peruvemba added. “Cambrios’ vision for the next era of display technology centers on 3D and flexible display such as curved car dashboards and wearable devices, like smart watches, that are flexible and comfortable. Also future applications of OPV and flexible solar panels will be able to wrap around large structures or be part of the sunroof in a car. From flexible OLED displays to e-paper displays, we are moving from the era of bulky, rectangular and fragile glass-based displays to an era of unique shaped, thin and conformable displays, and going three dimensional – and beyond – is going to be next big thing.”
For more information on materials for touch screens and displays, see the online version at www.printedelectronicsnow.com.