Can Gravure Successfully Lead the Printed Electronics market in printing OLEDs?

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1 Breanna Rittmann Graphic Communication Department College of Liberal Arts California Polytechnic State University March 2016 BB Can Gravure Successfully Lead the Printed Electronics market in printing OLEDs? By: Breanna Rittmann

2 Abstract This paper aims to explore whether gravure printing processes are capable of producing Organic Light Emitting Diodes (OLED). Current secondary research was compiled, showing the breakdown of both the gravure market as well as the printed electronics market as it pertains to OLED displays and lights. The benefits and drawbacks associated with gravure were exposed and compared to other processes like ink-jet printing. The research showed that gravure was not capable of being the best printing method at producing high-quality OLEDs and instead ink-jet is leading the way. Gravure is still able to produce OLEDs but not as high of quality and not as efficiently, but there is room for improvement. Figure 1, A flexible display using organic light emitting diodes, OLEDinfo.com Introduction OLEDs are primarily manufactured using ink-jet processes that are non-contact. Gravure, on the other hand, is a direct-contact process that has unique characteristics to contribute to successfully printing on thin, flexible substrates which are ideal for printed electronics. While gravure is more popular among more non-u.s. markets, it is starting to gain momentum in the states as its capabilities prove to deliver higher quality and greater sustainability. Secondary research was used in preparation of this research paper. Methodology The market share captured by gravure is only a fraction of the $76.7 billion dollar print industry (Moldvay, 2012). At 4.1%, commercial gravure printing is primarily used for advertising (about 28.4% of product revenue), catalogs and directories (22.5%), labels and wrappers (20.4%) and magazines and periodicals (17.8%) (Moldvay, 2012). Core competencies associated with gravure, according to lecture materials derived from Cal Poly s Web Offset and Gravure Printing Technologies class include: high-quality photo reproductions, extremely fast printing speeds, excellent low-key detail, light-weight flexible substrates, dry-trapping, larger press forms, and consistency. However, its disadvantages of expensive make-ready, along with a misalignment in the trend towards shorter print runs in the US, are a result of its decline. Flexography and rotary offset have seen huge gains in improving their quality and turnaround time that they have more often than not, pushed gravure out of many markets (Daniel, 2013). Manoj Garg, the general manager of Gulf Scan (the Middle East s largest provider of imaging and prepress solutions), says otherwise that gravure is more popular when it comes to the ratio of flexo to gravure in specific regions: Asia-Pacific has flexo to gravure at 20:80 respectively, Europe 55:45, North America 75:25, and Middle East and Africa have lost little to flexo and web offset so gravure still dominates in this region (Daniel, 2013). Commercial printers such as Gulf Scan in the Middle East and G3 Enterprises in Modesto, CA implement the strengths associated with rotogravure in their current equipment because its advantages will continue to deliver high-quality more consistently than other processes as well as remain the superior, easier-to-use technology for many regions (Daniel, 2013). According to the newest findings in the drupa 2016 report, gravure and flexography are both seeing a significant growth in the packaging sector with flexo growing +18% and gravure a modest but stable +3%. Although packaging is a stable sector for rotogravure, there is still much more room for growth in other markets such as printed electronics and other multifunctional technologies. These technologies that demand a significant threshold for high-quality combined with thin, flexible substrates (Figure 1), will continue to request gravure as its go-to printing process. The market for multifunctional technologies, such as printed electronics, is estimated to be $40.2 billion by 2020 (Markets and Markets, 2016). This number includes materials (substrates and inks), technology (screen, gravure, inkjet, and flexography), and applications (displays, sensors, OLEDs & PVs) (Markets and Markets, 2016). The industry breakdown shows OLEDs as making up the majority of the market in both displays and 1

Figure 2, The printing industry market segments, Das & Harrop, 2015 lights as shown in Figure 2 (Das & Harrop, 2015).

Over 3,000 companies in the world are pursuing printed, organic, and flexible electronics because this new technology has the capabilities to be extremely efficient, yield low-cost, execute improved

Currently, industry leaders are calling for a focus in developing the markets for printed electronic wearables (as shown in Figure 3), and printed electronic products for the automotive industry

3 Figure 2, The printing industry market segments, Das & Harrop, 2015 lights as shown in Figure 2 (Das & Harrop, 2015). OLED technology can be found in the many products that have made their way into the market today, like Samsung s OLED TV displays and its Galaxy S6 mobile phone (OLED-info, 2016). Over 3,000 companies in the world are pursuing printed, organic, and flexible electronics because this new technology has the capabilities to be extremely efficient, yield low-cost, execute improved performance, and retain better environmental credentials (Das & Harrop, 2015). Currently, industry leaders are calling for a focus in developing the markets for printed electronic wearables (as shown in Figure 3), and printed electronic products for the automotive industry (OE-A News, 2015). These market segments, specifically for automobiles, will benefit mainly from OLED displays such as pop-up warnings on windshields, and other interior, smart displays that engage the customer and enhance their vehicle properties. There is Figure 3, A wearable printed electronic, appleinsider.com a high potential for OLEDs to be implemented into these markets, and the demand for multifunctional, low-cost, printed electronic products will need to be required to manufacture. Therefore, finding the best processes to manufacture OLEDs inexpensively, while delivering high-quality with high-volume, will be essential for the success of OLEDs in the future. OLEDs are currently manufactured in a variety of different ways. Specifically in the conventional print market, OLEDs are primarily manufactured through an inkjet process. Inkjet is common because the high-precision nozzle is capable of controlling deposition of a solution in specific locations on a substrate and can provide easy and fast deposition of polymer films over a large area (GE Global Research, 2008). Another characteristic for manufacturing OLEDs are the roll-to-roll processes as they are ideal for cost savings involved with high volume production. Researchers at the Holste Centre were able to successfully produce over 2.5km of roll-to-roll barrier film (Flex-o-Fab, 2015). The project manager Date Moet said, Roll-to-roll production will be essential to bring flexible OLEDs to market at an affordable price. By demonstrating the first OLEDs on a high performance R2R produced flexible barrier foil, we have taken a major step towards commercial production (Flex-o-Fab, 2015). Another characteristic that OLEDs will benefit from is an additive process. Traditional manufacturing methods of electronics require a subtractive process, which is very wasteful. However, printing is an additive process, which allows for just the right amount of solution without the excess amount of waste. This knowledge opens the door for the printing industry to enter the new and exciting market of printed electronics as it relates to the production of OLEDs. In order to understand which printing processes would best suit the production of OLEDs, it is important to dissect the layers of what makes an OLED function. According to Figure 4, many different layers are laid on a substrate to a total thickness of about nanometers thick (200 times smaller than a human hair) (Freudenrich, 2016). OLEDs work by emitting light through a process of electrophosphorescence (Figure 5). An electric current flows from the cathode to the anode, passing through the organic layers, which creates movement among the electrons. When the electrons bond with other elements, they give off energy in the form of light, depending on the amount of electrical current being sent through the OLED (Freudenrich, 2016). Given this basic summary of how an OLED works, it still is quite complex and this is all 2

Combining gravure printing processes with the manufacturing of OLEDs is the proposed question of this research.

4 Figure 4, OLED structure, Freudenrich, 2016 happening at the microscopic level. Therefore, each layer must contain the highest precision of quality and must not have any gaps or particles that could corrupt its performance. Combining gravure printing processes with the manufacturing of OLEDs is the proposed question of this research. Understanding the significance, core competencies, and drawbacks from each technology is vital when deciding if the pair should be mated into one. They must be able to complement each other in order to achieve the desired success of a low-cost, light-weight, flexible, and more durable OLED. The attributes that gravure can bring to the production of OLEDs are many. As mentioned before, the roll-toroll process is a key element associated with gravure and it will also be beneficial for making OLEDs. By using a substrate in roll form and running it continuously throughout a press, output is greatly increased due to high speeds and decreased waste, which means higher cost savings and lower costs per printed unit which is extremely important in order for OLEDs to remain competitively priced (Gaspar, 2015). Utilizing gravure s roll-to-roll drives prices down to make OLEDs more affordable for everyone. Another attribute associated with gravure is its precision and high resolution print cells. Gravure has the ability to print a variety of functional materials and fine lines with resolutions below Figure 5, The OLED process, Freudenrich, µm (Hösel, 2013). Dry-trapping is another positive attribute that gravure passes along to manufacturing OLEDs. Since gravure ink is typically solvent-based, the dry time between each pass of a cylinder is greatly reduced, allowing for optimum registration necessary for OLEDs. Inks need to be contained within the designated area during the drying step, remaining so located during subsequent processing steps (Gaspar, 2015). Since printing OLEDs involves putting down as fine of details to that of pixels, gravure can get close to offering those high resolution dots with its microscopic cells. Researchers at Sungkyunkwan University in Korea said, We were able to achieve a 51 nm thick and 3.7 nm rough MEH-PPV layer with the gravure printing process and subsequent solvent printing treatment and an OLED was fabricated using the gravure printed organic layers. An improvement of the brightness and 3

5 efficiency was observed due to the improved roughness of the organic layers (Kim, 2010). Here in this example, due to gravure s laser-engraved print cylinder, high resolution can be achieved with microscopic sized print cells, an attribute required to print OLEDs. Thin, flexible substrates are also vital in the production of flexible OLEDs, which are gaining demand in the wearable printed electronics market. Gravure is able to deliver printed matter on a wide variety of substrates, including super thin materials. Its process, as shown in Figure 6, shows substrates feeding between two cylinders with the ink almost jumping out of the cell onto the substrate. This process allows the substrate to remain smooth, not be stretched or compressed too tightly between the cylinders. An ESA (electrostatic assistant) is a novel innovation that has allowed gravure to improve its processes dramatically with delivering homogeneous ink deposition, ideal for the manufacture of OLEDs where gaps in circuitry lines are impermissible. Figure 6, The gravure printing process, Iggesund.com Some drawbacks associated with gravure printing are its direct-contact attributes. OLED functions can be significantly reduced if any dust or particulates become deposited on the substrate or between the layers. Depending on the size and nature, they can destroy deposited layers, cause leaks after encapsulation, and become nucleation points that cause faster aging and destruction of OLED pixels (MBRAUN, 2015). Since ink-jet is the only printing process that is non-contact, it minimizes contamination risks that are associated with other printing methods (Gaspar, 2015). Some of the main challenges that gravure faces is its low emission efficiency (Gaspar, 2015). The VTT Technical Research Centre in Finland found that The luminosity of [gravure and screen printed] OLED (lm/w) amounts up to around one third of an LED s luminosity. It has one advantage in that OLED emits light throughout its entire surface, whereas LED is a spotlight technology (Ford, 2015). So trade-offs do happen when it comes to new technology. Because OLEDs create light at the source, they don t need a backlight that conventional LEDs would need. However, this means that sometimes OLEDs aren t as effective at performing as well or even better than traditional, thicker, LEDs. However, the author of OLED Fundamentals says that even though gravure printed OLEDs lack efficiency, recent advances show promise of improvement (Gaspar, 2015). Since gravure uses primarily solvent-based inks, this can cause wash-out. Gaspar says that, during solution deposition of one organic layer on top of another, the solvent penetrates into the underlying layer and leads to swelling or even wash-out (where the underlying layer is actually removed). Since gravure uses solvent-based inks for fast dry time, they may have to make some tradeoffs in order to achieve maximum manufacturing abilities when it comes to high-quality OLEDs. The biggest issue that gravure faces when successfully printing OLEDs is perfect registration. Because gravure is a traditional printing process that uses cylinders for each different ink, there are many variables to how those inks line up with one another. According again to Cal Poly lecture materials, there are many different registration techniques used in gravure: side-lay registration, lateral registration, and circumferential registration. In order for a roll to be aligned throughout the press, controls with the side-lay of the actual roll-stand need to be adjusted. Moving cylinders laterally within the printing unit are controlled with lateral registration instruments. And circumferential registration can be controlled by packing the cylinder to increase the diameter of the printing cylinder. All these registration variables increase the risk of mis-registration and timely make-ready. Where uniformity from pixel-to-pixel is of the utmost importance when manufacturing OLEDs, gravure may struggle to achieve perfect registration and deposition (Gaspar, 2015). Creating plates for gravure cylinders require a laser engraver that is capable at running at extremely high speeds. However, ink-jet does not require 4

6 a plate, this makes inket printing one of the most costefficient ways of producing complex patterns ( Gaspar, 2015). The noted author again adds, Not surprisingly, the displays industry has initially focused on ink-jet printing as the preferred method for the production of OLED displays (Gaspar, 2015). While initially this may be the case, changes are frequent in this industry and those preferences could easily change. Results When looking at the attributes and setbacks that gravure printing faces when attempting to produce high-quality OLEDs, the consolidated research suggests that gravure may not be the best printing method for OLED manufacture. Ink-jet seems to be the leading printing method for producing high-quality OLEDs since it is non-contact and has a high-precision nozzle that can deposit material onto a variety of substrates at extremely high resolutions with high levels of control. The barriers gravure faces outweigh the benefits it currently brings to the OLED market. There are too many risks for contamination with direct contact printing, incapable of higher resolutions offered by ink-jet, too many trade-offs between inks and registration controls, and costly make-ready. Although its roll-to-roll features are what s driving the market for printed electronics in order to make it affordable and competitive, it will have to be stripped from its native printing process and instead applied to other, more suitable processes, like roll-to-roll ink-jet processes. As traditional print loses sales to other forms of digital media, the industry is looking for ways to rejuvenate its presses and get them running again. Printed electronics is a huge opportunity for the print industry and processes like gravure, ink-jet, screen-printing, and flexography still have opportunities to individually contribute to the printed electronic industry. Gravure, while unable to successfully lead the market in manufacturing high-quality OLEDs, still has the capabilities to produce lower-cost printed displays in things like posters and other one-time-use products that can be thrown away, recycled, and printed all over again. Otherwise, gravure needs to continue its research and development in order to improve in the areas it s weakest in when it comes to manufacturing OLEDs. Concluding Remarks Extensive secondary research was done to support this project and to adequately answer the question of whether gravure printing methods could be successfully married to OLED technology. The solution to answering the question was simply a concern of pooling the most up-to-date research into one consolidated paper. Secondary sources were all very up-to-date, with 10 of the 18 resources published from either 2016 or This research needed to be as up-to-date as possible because of the nature of this technology and how rapidly it is changing in the market. 2,580 words References Angel, B. (2008). The Analysis of the Viability of Electronics Printed by Gravure and Web Offset Lithography. Gravure Association of the Americas. Retrieved from: analysis-viability-electronics-printed-gravure-and-weboffset-lithography Cal Poly, (2016). Web Offset and Gravure Printing Technologies. Graphic Communication Department. collegesandprograms/collegeofliberalarts/ graphiccommunication/#courseinventory Daniel, B. (2013). Gravure s Bright Future in Middle East Packaging: Manoj Garg of Gulfscan. Packaging MEA. Retrieved from: gravure-in-the-middle-east-interview-with-manoj-garg/ Das R., Harrop, P. (2015). Printed, Organic, & Flexible Electronics Forecasts, Players & Opportunities IDTechEx. Retrieved from idtechex.com/research/reports/printed-organicand-flexible-electronics-forecasts-players-andopportunities asp Ford, J. (2015). Traditional Printing techniques combine in OLED display manufacture. The Engineer. Retrieved from Freudenrich, C. (2016). How OLEDs Work. How Stuff Works: Tech. Retrieved from howstuffworks.com/oled1.htm Gaspar, D. (2015). OLED Fundamentals: Materials, Devices, and Processing of Organic Light-Emitting GE 5

7 Global Research, (2008). GE Demonstrates World s First Roll-to-Roll Manufactured OLEDs. Gravure Magazine. 22(2), 30. Gilboa, R. (2016). Info Trend s Rob Gilboa Reports on the Digital Transformation of Industrial Printing. Package Printing. Retrieved from packageprinting.com/article/infotrends-ron-gilboareports-on-the-digital-transformation-of-industrialprinting/ Hösel, M. (2013). Gravure Printing. Plastic Photovoltaics. org. Retrieved from Kim, A. (2010). Nanoscale thickness and roughness control of gravure printed MEH-PPV layer by solvent printing for organic light emitting diode. PubMed. gov Retrieved from pubmed/ PIWorld. Retrieved from: third-drupa-global-trends-report-2016-available-soon/ Images Figure 1 OLED-info.com.introduction/ Figure Figure rumor-apple-testing-15-oled-displays-for-wearableiwatch Figure 4 - Freudenrich, 2016 Figure 5 -Freudenrich, 2016 Figure en/knowledge/the-reference-manual/ printing-and-converting-performance/gravure-printing/ Markets and Markets, (2016). Printed Electronics Market Worth $40.2 Billion by Retrieved from MBRAUN, (2015). Enclosure with laminar flow and inert atmosphere. OPE Journal. 10. Moldvay, K. (2012). Printing in the US Industry Report. IBISWorld. Retrieved from:m com/images/uploads/documents/32311_printing_in_ the_us_industry_report.pdf OE-A News, (2015). Moving from 2015 to the year 2016 OE-A is going abovbe and beyond to bring the organic and printed electronics industry to the next level. OPE Journal. 13. Oled-info (2016). OLED Technology: introduction and basics. Retrieved from oled-technology Flex-o-Fab (2015). Lighting by the Mile. OPE Journal. 10. PNEAC (N.D.). Gravure Printing. Retrieved from Printing Impressions. (2016). Third drupa Global Trends Report Shows Optimism for Growth in

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