Peel Testing of Screens and Displays
Organic light-emitting diode (OLED) is the next generation technology in the area of flat-panel displays, offering key advantages over traditional LED displays, including better brightness, higher contrast ratio, lower power consumption, and thinner panels. As a result, OLED technology can now be found in many consumer electronic devices, such as smartphones, tablets, TVs, and wearable devices, which has made the research in mechanical testing for OLEDs extremely important.
One of the most important aspects of reliability to understand is the lifetime of OLED panels, as they are highly sensitive to moisture and oxygen. Light emissions can be quenched when the organic materials are exposed to water, wherein the highly reactive cathodes can be easily corroded, due to moisture and oxygen. Effective encapsulation is essential to prevent oxidation and block permeation of water vapor and oxygen. One solution is to apply a UV-cured epoxy as a perimeter seal. Another involves using multi-layered structures of glass or PET substrates and OLED with a thin film of adhesives to bond the various layers.
A peel test, which is a simple mechanical test method for measuring interfacial strength and for characterizing adhesion strength, is recommended to address the challenges of OLED display panels. The Adhesive Peel fixtures are available in a few options, including a 90 degree peel fixture and a variable angle peel fixture. For the OLED display panels, a 90 degree peel test is often applied to measure the peel force. Furthermore, miniature 90 degree and miniature variable angle peel fixtures can be used for peeling thinner films or tapes. Pneumatic side action grips are recommended to hold the sample before peel. In cases of thin films, micro-pneumatic grips or grips with rubber coated grip faces can be used.
Instron’s 5900 Series and 3300 Series systems are suitable to perform the peel tests. Bluehill® Universal software is used to set up test parameters, such as peel length and peel speed to measure the force applied.