Abstract— Recent advances in both organic‐ and inorganic‐based electronics processed on flexible substrates offer substantial rewards in terms of being able to develop displays that are thinner, lighter, robust, and conformable, and can be rolled away when not required. In addition, plastic‐based substrates coupled with the recent developments in solution deposition and ink‐jet printing for laying down OLED materials and active‐matrix thin‐film‐transistor (TFT) arrays open up the possibility of cost‐effective processing in high volumes using roll to roll (R2R) processing. To replace glass, however, a plastic substrate needs to be able to offer some or all of the properties of glass, i.e., clarity, dimensional stability, thermal stability, barrier, solvent resistance, and low coefficient of thermal expansion (CTE) coupled with a smooth surface. In addition, a conductive layer may be required. No plastic film offers all these properties so any plastic‐based substrate will almost certainly be a multilayer composite structure. This paper will discuss the issues associated with selecting plastic materials, contrast the various options, and highlight how to gain optimum performance through process control. This will be illustrated with examples of film in use in flexible electronic applications.

Flexible displays and flexible electronics is an area generating considerable interest at present. The current paper will discuss the requirements of a base substrate for flexible displays and contrast the plastic films that are being developed for this application. The review will cover how the surfaces and properties of the films are being engineered to make them suitable for laying down barrier coatings and for laying down thin film transistor arrays.

DuPont Teijin Films (DTF) have developed engineered substrates specifically for the flexible electronics market. Teonex((R))Q65 is a biaxially oriented crystalline polyester with a tailored surface and it is emerging as a competitive material for the base substrate in OLED displays and active matrix backplanes. Given the dimensional reproducibility requirements in the display applications, uncontrolled moisture absorption during the processing cycle could potentially be far more significant than the inherent shrinkage of the base substrate. Understanding these effects and optimising the processing steps involved in device manufacture will be critical to achieving the ultimate performance that can be achieved with the base substrate.

SID Symposium Digest of Technical PapersVolume 36, Issue 1 p. 514-517 P-62: Latest Developments In Polyester Film For Flexible Electronics W. A. MacDonald, W. A. MacDonald DuPont Teijin Films, PO Box 2002, Wilton, Middlesbrough, UK, TS90 8JFSearch for more papers by this authorK. Rollins, K. Rollins DuPont Teijin Films, PO Box 2002, Wilton, Middlesbrough, UK, TS90 8JFSearch for more papers by this authorD. MacKerron, D. MacKerron DuPont Teijin Films, PO Box 2002, Wilton, Middlesbrough, UK, TS90 8JFSearch for more papers by this authorR. Eveson, R. Eveson DuPont Teijin Films, PO Box 2002, Wilton, Middlesbrough, UK, TS90 8JFSearch for more papers by this authorR. A. Rustin, R. A. Rustin DuPont Teijin Films, PO Box 2002, Wilton, Middlesbrough, UK, TS90 8JFSearch for more papers by this authorR. Adam, R. Adam DuPont Teijin Films, PO Box 2002, Wilton, Middlesbrough, UK, TS90 8JFSearch for more papers by this authorM. K. Looney, M. K. Looney DuPont Teijin Films, PO Box 2002, Wilton, Middlesbrough, UK, TS90 8JFSearch for more papers by this authorT. Yoshida, T. Yoshida DuPont Teijin Films, PO Box 2002, Wilton, Middlesbrough, UK, TS90 8JFSearch for more papers by this authorK. Hashimoto, K. Hashimoto DuPont Teijin Films, PO Box 2002, Wilton, Middlesbrough, UK, TS90 8JFSearch for more papers by this author W. A. MacDonald, W. A. MacDonald DuPont Teijin Films, PO Box 2002, Wilton, Middlesbrough, UK, TS90 8JFSearch for more papers by this authorK. Rollins, K. Rollins DuPont Teijin Films, PO Box 2002, Wilton, Middlesbrough, UK, TS90 8JFSearch for more papers by this authorD. MacKerron, D. MacKerron DuPont Teijin Films, PO Box 2002, Wilton, Middlesbrough, UK, TS90 8JFSearch for more papers by this authorR. Eveson, R. Eveson DuPont Teijin Films, PO Box 2002, Wilton, Middlesbrough, UK, TS90 8JFSearch for more papers by this authorR. A. Rustin, R. A. Rustin DuPont Teijin Films, PO Box 2002, Wilton, Middlesbrough, UK, TS90 8JFSearch for more papers by this authorR. Adam, R. Adam DuPont Teijin Films, PO Box 2002, Wilton, Middlesbrough, UK, TS90 8JFSearch for more papers by this authorM. K. Looney, M. K. Looney DuPont Teijin Films, PO Box 2002, Wilton, Middlesbrough, UK, TS90 8JFSearch for more papers by this authorT. Yoshida, T. Yoshida DuPont Teijin Films, PO Box 2002, Wilton, Middlesbrough, UK, TS90 8JFSearch for more papers by this authorK. Hashimoto, K. Hashimoto DuPont Teijin Films, PO Box 2002, Wilton, Middlesbrough, UK, TS90 8JFSearch for more papers by this author First published: 05 July 2012 https://doi.org/10.1889/1.2036488Citations: 10AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract DuPont Teijin Films(DTF) have developed engineered substrates specifically for the flexible electronics market. Teonex ®Q65 is a biaxially oriented crystalline polyester with a tailored surface and it is emerging as a competitive material for the base substrate in OLED displays and active matrix backplanes. To meet the demanding requirements of flexible displays the engineered substrates are likely to be multilayer structures. This contribution will discuss the mechanical properties of multilayer structures on flexing and the impact of the processing environment on dimensional reproducibility. Understanding the influence of these factors is critical to achieving the performance required of substrates for flexible electronic applications. Citing Literature Volume36, Issue1May 2005Pages 514-517 RelatedInformation

DuPont Teijin Films(DTF) are developing engineered substrates specifically for flexible electronics based on both PET and PEN where choice of film will depend on the end application. To meet the demanding requirements of flexible displays the engineered substrates are likely to be multilayer structures. This contribution will discuss the substrates, the planarising coatings, the mechanical properties of multilayer structures on flexing and the impact of the processing environment on dimensional reproducibility. Initial results on barrier performance will be outlined. Choice of substrate and understanding the influence of the above factors is critical to achieving the performance required of substrates for flexible electronic applications.

DuPont Teijin Films(DTF have developed a family of films engineered specifically for the flexible electronics market. Teonex®Q65 is a biaxially oriented crystalline polyester with an engineered surface and it is emerging as a competitive material for the base substrate in OLED displays and active matrix backplanes. This contribution will describe the properties of this film, its uniquely different property set compared to amorphous high performance films and discuss examples of the film in use in flexible electronic applications.

The microfocus X-ray beamline at the European Synchrotron Radiation Facility has been used to investigate the variation in molecular orientation and crystallinity in spherulites of the organic polymer poly-3-hydroxybutyrate (PHB). This is the first report of the correlation of optical and X-ray measurements on spherulitic polymer films where X-ray diffraction patterns have been recorded and displayed continuously in real time while the specimen was tracked in steps of 10 mum across an incident X-ray beam with a diameter as small as 10 mum.

A purpose-designed X-ray fibre diffraction camera has been used to record the variation in the wide angle X-ray scattering during the drawing and annealing of the organic polymer polyethylene terephthalate. Data were recorded at the Daresbury Laboratory Synchrotron Radiation Source using a Photonics Science electronic area detector interfaced to a Synoptics framegrabber as a series of frames with an exposure time of 40 ms for each frame. Frames could be displayed while the diffraction pattern was being accumulated allowing the experiment to be conducted in a genuinely real-time mode. The draw rate was varied from 20% per min to 72 000% per min and the draw temperature from 80°C to 140°C. The draw ratio in these experiments was designed to be 3.6:1. For the highest draw rates essentially all the change in the diffraction pattern was complete in less than 1 s. The degree of crystallinity and orientation observed in drawn samples depends on both the draw temperature and the draw rate. In particular for draw rates of 72 000% per min the high degree of orientation and crystallinity observed at a draw temperature of 80°C diminishes with increasing draw temperature until for draw temperatures of 140°C the pattern is essentially unoriented and non-crystalline.

The high brilliance of the Daresbury Synchrotron Radiation Source has been exploited in time-resolved x-ray fibre diffraction of changes in polymer conformation and organisation in response to patterns of mechanical and thermal stress similar to those followed during industrial processing. This has involved the development of a new x-ray camera which can be used in both wide and small angle diffraction and allows uniaxial drawing for draw rates up to 72,000% per minute (i.e. an increase in length by a factor of 720 in one minute) at temperatures from ambient to 400 degrees C. The use of electronic area detectors which display the diffraction pattern while it is recorded allow experiments to be conducted in real-time. The variation in the diffraction is recorded as a series of frames. The time to record a frame can be as short as 40 msecs.

A purpose-designed x-ray fiber diffraction camera has been constructed in the Keele University Physics Department to be used at the SERC Daresbury Laboratory Synchrotron Radiation Source. The camera allows time-resolved studies of the change in both the high- and low-angle diffraction patterns during drawing and annealing of polymer films to be recorded. Drawing of the films is achieved by two opposed stepper motors which allow films to be drawn uniaxially in both directions. The temperature of the sample environment can be controlled to within 1 °C by a radio spares proportional, integral, and derivative (PID) controller. Diffraction patterns can be recorded on the Enraf-Nonius TV FAST detector or on photographic film. Exposure times using the FAST detector are typically 5 s, representing a gain of approximately a factor of 5 over photographic film. The FAST detector has a further advantage over photographic film in that essentially an unlimited number of diffraction patterns can be recorded end-to-end while a structural transition is being followed. A video camera is incorporated to allow the variation in the gross appearance of the specimen to be recorded during drawing and annealing and to be related to the variation in the diffraction pattern. The application of the camera in the study of drawing and annealing of poly (aryl-ether-ether-ketone) (PEEK) is described.