Published in Military Embedded Systems
Until we’ve mastered the science of brainwave communications, vision and touch will remain the fundamental ways that users interface with avionics and vetronics systems. Today’s modern warfighters have grown up with smartphones and tablets with intuitive, multitouch projected capacitive (PCAP) touch screens. They rely heavily on these devices in their personal lives and they expect to have access to the same capabilities and conveniences in the field.
To date, the industry has relied primarily on ruggedized resistive touch screens, because resistive screens can be used while wearing gloves and don’t create interference issues. The limitations of early PCAP touch screens made them virtually unusable on defense and aerospace platforms. However, those issues have since been overcome. This progress means that rugged military displays can now provide users with the same familiar interface that they use with their smartphones and tablet devices.
PCAP versus resistive touch
Two layers of electrodes separated by an air gap sit just behind the screen in a resistive touch screen, with tiny plastic microbeads used to maintain the air gap between the electrode layers. To register a touch, users must apply enough pressure to the screen to squeeze the microbeads together so the two layers of electrodes touch.
In contrast, a PCAP touch screen is composed of solidly bonded optical screen layers. As a result, there is no air gap or microbeads that must be depressed. Instead, the screen detects and reacts to the static electrical charge of the object that touches it.
Clarity, contrast, and readability
Because they don’t include an air gap between screen layers or plastic microbeads, PCAP touch screens don’t suffer from the reflection and image clarity issues that resistive touch screens experience. They provide a crisper, higher-quality image and higher contrast levels that make it easier for the user to see and absorb screen content at a glance.