As more and more companies are gearing up and demonstrating flexible display prototypes (LG, Nokia and earlier this year at CES 2013, Samsung's Youm display are just a few of the latest examples), the need for protection of these new devices that are freed from the constraints of conventional rigid form factors is highlighted once more.
Fig 1. Samsung's flexible display, demonstrated at CES 2013
Fig 2. Nokia's Kinetic display
IDTechEx Research, in its latest report on the topic of flexible encapsulation "Barrier Films for Flexible Electronics 2013-2023: Needs, Players, Opportunities" (www.IDTechEx.com/barrier), is forecasting the market for flexible barrier films to conservatively grow to just over $34 Million by 2016. Up until that point, over 95% of the market is accounted for from a slowly growing market for flexible photovoltaics based on CIGS and a-Si platforms.
Fig 3. A percentage breakdown of the market by applications for flexible barrier films in 2013. Source: IDTechEx Research report "Barrier Films for Flexible Electronics 2013-2023, Needs, Players, Opportunities" (www.IDTechEx.com/barrier)
The really significant growth though, is expected to kick in once flexible display technologies move out of the prototyping stage and start becoming commercial products, changing the way consumers interact with their portable electronic devices. By 2023, the market for flexible barriers will already be over $240 Million, with display technologies accounting for over a third of that value.
Applications: OLED displays and lighting
The realization of flexible OLED applications still requires further advances in thin film encapsulation technology due to OLED sensitivity to oxygen and moisture. Several barrier architectures are possible and each technology is characterized by different materials, manufacturing processes and final barrier properties. The widely quoted requirement for water vapour transmission rate (WVTR) for an OLED lifetime of >10,000 hours is 10−6 g/m2/day. Barriers of this level of performance are not widely available yet but several barrier technology developers already have manufacturing facilities for small volumes and samples available.
On the other hand, flexible electrophoretic displays (EPDs) are already being commercialized but that's mainly due to the fact that EPDs are not sensitive to oxygen and moisture. In fact, IDTechEx Research shows that a small amount of moisture is actually beneficial for EPDs so the technology has little or no need for a high performing barrier layer that minimizes water vapour permeation.
Fig 4. Flexible e-reader from Wexler.
Flexible solar cells on the other hand are already available in the market, currently serving low-volume markets such as portable power (portable solar chargers, apparel-integrated PV etc.) and emerging segments such as power for developing countries. Building and automotive integrated PV is a major target market for flexible thin film PV cells, given their light weight, versatility in form factor and ease of installation/integration. Costs in these market segments are still prohibitive though, hence the limited volume of deployments and slow uptake of the technology. Water vapour transmission rates (WVTR) for these types of solar cells, in order to serve their target ranges from 10−3 g/m2/day for CIGS and a-Si all the way to 10−6 g/m2/day for the more sensitive dye sensitized solar cells (DSSC) and Organic PV technologies. The lower level necessary for CIGs or a-Si encapsulation is already achieved by many barrier film manufacturers which indicates a technological maturity and a market that will grow depending on power output, cost metrics and finally, end-user adoption.
IDTechEx Research were the first to identify the need for a market report on flexible encapsulation of electronics and launched the first report back in 2008. The new report is being launched as IDTechEx Research has been following the developments and trends in this space over the past few years. One of the most important such trends is definitely the increasing interest in flexible glass encapsulation.
With the introduction of flexible glass from several companies in the past few years, the competition for encapsulation becomes more intense as, there is now a new option being commercialized that would allow for perfect protection from oxygen and moisture, without having to rely on plastic substrates with inorganic coating deposited on them. Flexible glass can inherently be very low cost; after all, it's only glass, only thinner, which could translate to less material utilization hence, lower raw materials and total costs. Unfortunately things are not as simple, given the fact that handling issues with flexible glass make its development, transportation, usage, etc. a bit more complex. As cracks are initiated from the edges of the glass tabbing is utilized in order to protect fractures from occurring and propagating.
Fig 5. Corning's Flexible glass with protective tabbing on the edges. Source: Corning
What is expected in the next few years is increasing competition between the developers of different technologies. Initially, flexible glass has a handicap as it is dealing with its handling issues. On the plus side for flexible glass developers, they already have long standing relationships with major display and PV manufacturers worldwide through their rigid glass businesses, a position which allows them for direct access to potential customers for their new flexible offerings (e.g. Corning, Schott, NEG). Overall, we are expecting to start seeing penetration of glass solutions in the flexible electronics space a bit later than solutions based on polymers but from 2016 onwards glass solution providers are expected to start slowly increasing their market share.
Further insight on the above topics is included in the newly launched IDTechEx report "Barrier Films for Flexible Electronics 2013-2023, Needs, Players, Opportunities" (www.IDTechEx.com/barrier) in which over 20 major developers of barrier film solutions are profiled in a comprehensive overview of all the technologies (dyads, flexible glass, multiple inorganic layers on flexible substrates), end user needs and requirements as well as a chapter dedicated to measurement techniques and ways to achieve the necessary resolution when evaluating films characterized by low levels of WVTR.
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