Recently, smartphone developers within the country introduced the liquid damage indicator to prevent the misuse of the warranty policies of their products. Liquid damage indicators (LDI) can be seen as a type of sensor that shows if the phone has been underwater due to the negligence of the customer. However, cases where the indicator changes color despite the phone not being dropped underwater has been reported occasionally, with customers continually raising their dissatisfaction with the products. On one occasion, a smartphone maker and a consumer took the warranty matters to court, with Apple settling for 53 billion won back I 2013.<?xml:namespace prefix = "o" ns = "urn:schemas-microsoft-com:office:office" />

Recently, SNU Professor Byeng Dong Youn’s research team designed an innovative reliability evaluation on the basis of the “accelerated lifespan test”. The team observed the world’s first laboratory detection of a color change in the LDIs while following the recommended usage within the owner’s manual. Just like how condensation appears on one’s glasses when he/she moves from a cold area to a warm area, the fact that sudden temperature changes can change the color of the LDI was proved by the research team. In conclusion, it was a research that could potentially show the misjudgment of water contact with the LDI despite the device not actually coming into contact with water. On top of that, the research team was the world’s first to derive a model of performance degradation of the LDI from the results of the “accelerated lifespan test”. The performance degradation model derived from two physical phenomenon (Condensation, Spread of water from porous materials) shows the reliability of the LDI with regards to warranties within the different environmental conditions of consumers. 

The research is currently raising alarms about the adverse effects the LDIs could bring to smartphone developers. Understanding the possibly faults of the LDI considering the various usage conditions of consumers, setting up measure to these problems are more urgent than ever. Additionally, smartphone developers need to move away from the basic method of indirectly determining water contact through a simple color change in the LDI and need to reveal the root cause of the fault.

The following research was published on online version of Reliability Engineering & System Safety (2015 May volume), one of the most trustworthy and notable SCI Journals and is currently available for free.&nbsp;

               
                                                            [Source: 3M]
※ Journal Title: An empirical model to describe performance degradation for warranty abuse detection in portable electronics
Article: http://www.sciencedirect.com/science/article/pii/S0951832015001313