| Objectives | Background | Approach |
To develop reliability assessment and design decision support
software capability for liquid crystal displays.
One of the critical drivers in the development of advanced communications and computing systems is display technology. The need for smaller size, lighter weight, and higher resolution has placed new demands on the design of displays and their resulting quality and reliability. These factors have driven the move from traditional cathode ray tube (CRT) displays to liquid crystal displays (LCDs). While CRTs still hold a price/visual performance advantage over LCDs, that advantage is shrinking, and, in many applications, is subordinate to the need for the thinner and lighter design provided by LCDs.
Liquid crystal displays are composed of a three unit primary assembly consisting of the thin film transistor addressing panel, the color filter panel, and the liquid crystal held between the two panels. This primary assembly is then combined with polarizers, backlights, and the associated drive electronics in a frame to create the full display unit. This study will concentrate on identifying and developing models for the failure mechanisms associated with the primary assembly. Issues of polarizer, backlight, and frame failure are not within the scope of the study, and design of driver boards for reliability has been well addressed in previous CALCE work.
As both the thin-film transistor addressing panel and the color filter panel are constructed using thin film deposition processes developed for the creation of planar devices by the semiconductor industry, much of the previous knowledge base of CALCE in the study of manufacturing defects and failure mechanisms in planar semiconductor devices and their on-chip interconnection will be of value in this study, as will our understanding of back-end processes such as attach. However, it will be necessary to adapt this knowledge to the unique electrical and mechanical structures used in the LCD industry.
This project will consist of developing web based design decision support software for liquid crystal displays that will contain the state-of-the-art failure models. The approach to creating this software will include a literature search to identify the models currently used to assess the susceptibility of LCD designs to failure and their incorporation into a web based handbook and analysis tool. In addition, the project will identify where there are gaps in the fundamental understanding of LCD failure, and propose plans for addressing those gaps through fundamental physics-of-failure modeling.