Designing COTS LCD Displays For Rugged Applications
- Thursday, 01 March 2012
Innovation, demand, and falling prices have resulted in high quality large format commercial-off-the-shelf (COTS) LCD displays moving from the living room to high availability, mission critical applications.
The human cognitive ability to perceive and process data from several heterogeneous outputs and react correctly to the information is greatly enhanced with the proper representation of graphical data. Large format displays allow for the consolidation of multiple heterogeneous displays, fonts, dials, gauges, numbers, into a single homogeneous representation of situational awareness.
Mission critical systems such as industrial control rooms, shipboard control, building monitoring and mass notification have benefited from the display of intuitive information on large screen displays.
For example, for many years, firemen first to arrive on scene have been met with screeching fire alarms, indicator lights on a fire panel and “as built” drawings locked in a cabinet with a special key. Today they could now be greeted by a large format LCD with a 3D view of the building, smoke flow diagrams, and other information to help them understand the situation and make better decisions faster. Occupants leaving a building can also benefit from graphical mass notification information which can be tailored for the situation.
Ship systems comprised of different steam gauges and manual operations such as sticking tanks and closing valves can now be automated with their instruments consolidated on a single screen or redundant large screens, showing graphically status of fuel, water, and ballast, improving productivity and decreasing workload.
Similarities exist on industrial control systems where several CRTs or smaller LCDs are being replaced by a large LCD with clever graphics designed for human factors and perception.
The challenge of these applications is the proper integration of the COTS LCD technology to meet requirements of availability, reliability, and intended use.
Large LCD panels are coming out of the factory with brilliant colors and near perfect viewing angles using ASV (Advanced Super View) and IPS (In Plane Switching) innovations driven by consumer TV requirements. The challenge is ruggedizing a display to preserve as much of this as possible, this while shielding against objects, liquids, sunlight and EMI. These surface choices may adversely affect the optics of the panel, which can be reduced through bonding techniques to eliminate air gaps.
Degree of Environmental Protection
Depending on its intended use, mission critical displays may be required to operate in an environment subject to dust, sand, fog, chemicals, falling or spraying liquids (broken pipes, sprinklers, etc). Protection of the LCD panel involves designing an outer enclosure capable of keeping dust and liquids out while keeping the display operating in its proper temperature range.