A method and system for accurately measuring bending strain of flexible electronic devices

Abstract

The invention belongs to the technical field related to flexible electronic testing, and discloses a method and system for accurately measuring the bending strain of flexible electronic devices. The method includes the following steps: (1) providing an ultra-thin strain sensor; The thin strain sensor is pre-fixed on the flexible electronic device, and the ultra-thin strain sensor and the flexible electronic device are clamped to squeeze out excess glue, and then the fastening of the ultra-thin strain sensor is completed after the glue is cured; (3) the ultra-thin sensor It is integrally connected with the flexible electronic device to the test device, and the loading measurement is performed to collect multiple sets of experimental data; (4) Calculate the strain of the ultra-thin strain sensor during the buckling process according to the gauge coefficient of the ultra-thin strain sensor and the obtained experimental data , and then use the modified positive coefficient to correct the obtained strain, and then the real strain of the flexible electronic device to be tested can be obtained. The invention improves the measurement accuracy and has good applicability.

Description

technical field [0001] The invention belongs to the technical field related to flexible electronic testing, and more specifically, relates to a precise measurement method and system for bending strain of flexible electronic devices. Background technique [0002] Flexible electronic devices, such as flexible display screens, structural health monitoring equipment, aircraft smart skins, electronic skins, and flexible solar cells, have subversively changed the rigidity of traditional information devices because they can withstand large deformations such as bending, torsion, and folding. The physical form realizes the wearability and implantability of traditional electronic products, conformal contact and perfect integration with the human body, and is the strategic commanding height of future information. With the increasing importance of flexible electronic devices, people have higher and higher requirements for their mechanical properties. Especially in the working environme...

AI Technical Summary

Problems solved by technology

However, there are certain limitations in the preparation of corresponding strained layers on flexible electronic substrates. For example, metal strained layers generally need to be carried out in a high-temperature environment, so it cannot be used in ordinary films with PDMS (polydimethylsiloxane) with poor heat resistance. alkane) as the substrate of flexible electronics, the preparation process is also vulnerable to the size limit of flexible electronic devices or even damage the flexible electronic devices, which does not have wide applicability and portability, so the use of ultra-thin strain sensors with packaged flexible substrates has become the main test A means of bending performance in flexible electronics

[0004] However, when testing with ultra-thin strain sensors, there are still some problems in the strain measurement of flexible electronic devices: how to ensure that due to the sensitivity of the adhesive layer, the contact between the ultra-thin strain sensor and the flexible electronic device is The interface is very likely to have a slip failure mode, which leads to test results that cannot truly reflect the real bending strain of the flexible electronic device; This leads to the offset problem of the neutral layer of the flexible electronic device to be tested, which causes the strain of the sensing grid to be different from the strain on the outer surface of the device to be tested; To ensure the integrity of no residual bubbles, ultra-thin viscous layer and ultra-thin devices can be obtained, so as to ensure the accuracy of the test, so accurate measurement of the true bending strain of flexible electronic devices is an urgent problem to be solved

For these problems, there are already some solutions, such as Yewang Su et al. (Chen, Y.*; Su, Y.*, Adhesion-Free Thin-Film-LikeCurvature Sensors Integrated on Flexible and Wearable Electronics for Monitoring Bending of Joints and Various Body Gestures.Advanced Materials Technologies, 2019,4(2):1800327.) Considering the influence of interface sliding between ultra-thin strain sensors and flexible electronic devices during the test, a double-layer strain sensor is designed to test flexible electronics. However, the This method is only suitable for cases where the interface slides slightly

At the same time, the patent (patent 109505838A, CN 204944424, CN104944424) considers the influence of the adhesive layer, and proposes a push-and-extrusion type placement equipment to solve the problem of uniformity, thickness, and no bubbles of the adhesive layer when the strain sensor is mounted during the test process. and impurities, etc., but this method is only suitable for flexible strain sensors with large plane type, stiffness, and thickness, and is not suitable for the measurement of ultra-thin flexible sensors and flexible electronic devices under curved surface morphology; another example is the patent CN102001617A proposed A displacement loading method for flexible electronic devices is used to correct the influence of loading factors. However, this method only considers the influence of loading factors, and does not consider the influence of adhesive layer, thickness of flexible electronic devices and other factors. Especially for ultra-thin flexible electronics, it must Ensure that the adhesive layer is thinner, so that the neutral layer shift is small

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