Mechanical Performance of Thin Films in Flexible Displays

Lewis, Jay; Grego, Sonia; Vick, Erik; Chalamala, Babu; Temple, Dorota

doi:10.1557/proc-814-i8.5

Cited by 19 publications

(20 citation statements)

References 27 publications

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“…The X-Y-θ method assumes a uniform bending deformation along the length of devices. In the testing process, [65] one end of the sample was fixed in a flat plate and the moving end was controlled by a rotary motorized actuators. As shown in Figure 7, the length between two ends is L 0 , and the initial horizontal direction is defined as X axis.…”

Section: X-y-θ Methodsmentioning

confidence: 99%

Mechanical Analyses and Structural Design Requirements for Flexible Energy Storage Devices

Mao

Meng

Ahmad

et al. 2017

Advanced Energy Materials

192

146

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degree of the entire electronic systems. In the integrated flexible electronic system, energy storage devices [14,[16][17][18][19][20] play important roles in connecting the preceding energy harvesting devices and the following energy utilization devices (Figure 1). Rechargeable secondary batteries and supercapacitors (SCs) are two typical energy storage devices. [21] Several excellent review papers [21][22][23][24][25][26] reported significant progresses achieved in flexible lithium-ion batteries (LIBs) and SCs by taking advantage of novel electrode materials, current collectors, and solid-state electrolytes. The application areas and lifetime of flexible power sources strongly depend on their mechanical deformation tolerance and the electrical property retention under deformation. Qualified flexible power sources should be able to endure high strain induced by external mechanical deformation, such as bending, compressing, stretching, folding, and twisting, while maintaining their electrochemical performance stability and structural integrity. Therefore, the mechanical reliability assessment and electrical property analysis of flexible devices need to be given much attention for future application.Tolerance in bending into a certain curvature is the major mechanical deformation characteristic of flexible energy storage devices. Thus far, several bending characterization parameters and various mechanical methods have been proposed to evaluate the quality and failure modes of the said devices by investigating their bending deformation status and received strain. Some of these mechanical metrologies were derived from the early research on flexible semiconductor devices of micro-electromechanical system (MEMS) [27,28] and TFTs. [29] However, comparing those numerous measurement data with one another is difficult because of the various theories and methods adopted by different research groups and the lack of unified assessment criteria. [26] The flexibility of flexible devices is generally realized not only by use of intuitive soft electrode materials but also by optimizing their mechanical structural design. [25] Detailed analysis on bending mechanics combining experimental and theoretical results provide not only reliable test methods to describe the bending state but also guidance for configuration design of devices against mechanical failure.The current review emphasizes on three main points: (1) key parameters that characterize the bending level of flexible energy storage devices, such as bending radius, bending Flexible energy storage devices with excellent mechanical deformation performance are highly required to improve the integration degree of flexible electronics. Unlike those of traditional power sources, the mechanical reliability of flexible energy storage devices, including electrical performance retention and deformation endurance, has received much attention. To provide the guideline for the construction design of devices, the strain distribution and failure modes in the entire architecture should b...

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Section: X-y-θ Methodsmentioning

confidence: 99%

Mechanical Analyses and Structural Design Requirements for Flexible Energy Storage Devices

Mao

Meng

Ahmad

et al. 2017

Advanced Energy Materials

192

146

View full text Add to dashboard Cite

show abstract

“…The initial resistance of samples were measured and are comparable to theoretical value as in Table 1. The collapsing radius test method is adopted for our experiment because it offers simple setup and testing a function of radius [4]. Since the sample does not conform to a constant radius for the bended area and extracting the true minimum radius of curvature at the center point between the plate is not trivial [4,5], we use a new approach to simplify the radius measurement.…”

Section: Methodsmentioning

confidence: 99%

“…The collapsing radius test method is adopted for our experiment because it offers simple setup and testing a function of radius [4]. Since the sample does not conform to a constant radius for the bended area and extracting the true minimum radius of curvature at the center point between the plate is not trivial [4,5], we use a new approach to simplify the radius measurement. By fitting an ellipse to the digital image of bended curve of the sample and measuring its two axis a and b, as shown in Figure 2, the radius of curvature can be calculated as R= b2/a.…”

Section: Methodsmentioning

confidence: 99%

Mechanical Limitations of Materials for Steel Foil Based Flexible Electronics

et al. 2007

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This work investigates mechanical limitations of thin film materials on steel foil substrates for flexible electronic applications. A three layer structure consisting of 100μm thick stainless steel foil as the substrate, followed by 1μm thick spin-on-glass passivation layer and 0.3μm thick patterned aluminum interconnect layer on top with varying widths between 10-35μm. A collapsing radius test method was adopted for the bending experiment and an elliptical curve fit was used to facilitate the strain measurement. The failure strain of aluminum interconnect layer was detected by monitoring the continuity of the test circuit during the experiment. The corresponding results reveal that the passivation layer cracked at a tensile strain of 0.46% and delaminated at a compressive strain of 0.68%. The metal interconnect layer ruptured at a tension strain of 1.26% and delaminated from the substrate at a compressive strain of 1.22% due to the delamination of the passivation layer underneath.

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“…Dealing with flexible displays, Grego et al [2] evaluated two measurement systems, each with different advantages in bending test capability: a collapsing radius system [3] and an X Y bending system [4]. In the collapsing radius set-up, the bending shape is, however, not exactly cylindrical and a numerical study [5] concluded that, assuming perfectly elastic behavior, the minimum bending radius experienced by the sample is 20% smaller than the half platedistance.…”

Section: Introductionmentioning

confidence: 99%

Electrical characterization of metal electrodes deposited on flexible polydimethylsiloxane substrates for folding test

Lee

Liao

Lee

et al. 2014

2014 9th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT)

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The objective of this study is to present an electrical characterization of metal electrodes deposited on flexible substrates for folding test. In order to quantize folding conditions, flexiblecharacteristic inspection system (FCIS) [1] for folding function is utilized to control radii of curvature of the flexible substrates. As a result, the new technique successfully measures electrical characteristics of flexible polydimethylsiloxane (PDMS)/gold electrodes for analysis during the 0/m to 200/m curvature folding cycles. Inspection results of folding characteristics depicted on flexible displays help a designer or maker of flexible displays design useful and comfortable flexible electronic products.

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Mechanical Performance of Thin Films in Flexible Displays

Cited by 19 publications

References 27 publications

Mechanical Analyses and Structural Design Requirements for Flexible Energy Storage Devices

Mechanical Analyses and Structural Design Requirements for Flexible Energy Storage Devices

Mechanical Limitations of Materials for Steel Foil Based Flexible Electronics

Electrical characterization of metal electrodes deposited on flexible polydimethylsiloxane substrates for folding test

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