Justin Coleman, display business manager at Review Display Systems
Public transport systems, utility vehicles, airborne craft and marine vessels are regularly operated in a wide range of terrestrial, subterranean, atmospheric, and marine environments. The display and touch technologies that feature in the operator and user control systems in these transportation systems need to provide reliable and dependable operation under a wide range of operating environments and conditions.
A multitude of operating environments will present challenges that include temperature extremes, change of temperature, magnetic and electrical noise, mechanical shock and vibration, ultraviolet radiation, and the potential for fluid/liquid ingress. These factors all pose potential threats to reliable and consistent touchscreen operation.
Graphical user interfaces featuring displays with integrated touchscreens must provide reliable and stable operation under temperature extremes while also coping with rapid temperature variations.
Leading global touchscreen solution provider AMT, develops and supplies PCap (projected capacitive) touch panels that are specified to an automotive standard operating temperature range of -40°C to +85°C, and a storage temperature range of -50°C to +90°C. Temperature change is tested with operational thermal cycling of -40°C for 30 minutes, followed by +85°C for 30 minutes, for 100 cycles.
Transportation systems and infrastructure equipment will often be extensively operated in outdoor environments, and as a necessity need to be able to withstand prolonged exposure to high levels of ambient light and direct sunlight. A system that is unprotected and subjected to extended UV (ultraviolet) radiation can cause yellowing, hazing, and material ageing and degradation.
AMT PCap touchscreen solutions have been successfully tested to strict industry standards including accelerated UV ageing and weathering standard ASTM G154 Cycle 1 – 1,000 hours, and environmental conditions standard MIL-STD-810H Pro 1 – 1,000 hours.
Light reflection in high ambient light environments can impact display image clarity and visibility. Optical bonding is used to eliminate internal air gaps which reduces internal reflections and refraction effects. AMT also offers touch panels with a Low-Reflective (LR) design, to aid and assist improved image legibility in bright light conditions.
EMC and noise immunity
Electromagnetic compatibility (EMC) is important in all transportation applications. The Federal Aviation Administration (FAA) regulations require all devices installed on aircraft to pass certification to DO-160 Environmental Conditions and Test Procedures for Airborne Equipment. Employing suitable integration and firmware adjustment, AMT PCAP touch solutions can meet DO-160 Conducted RF Emission at 150KHz to 152MHz and Radiated RF Emission at 100MHz to 6000MHz test standards. Hardware and software design solutions from AMT can enable excellent electromagnetic immunity for all in-vehicle and transportation applications.
Designed for purpose
Operator displays on public transport systems will often adopt dual-screen redundancy designs to mitigate against unexpected failure circumstances. A dual-screen operator display can incorporate two touchscreens using just one piece of integrated cover glass. The electric fields generated between the two projected capacitive (PCap) touch screens have the potential to interfere with each other.
AMT have conducted many internal tests and used different signal frequencies to mitigate the problem of interference and ensure dual-screen applications can be deployed successfully.
Developing and manufacturing touch screens and controllers, AMT is firmly established as a leading global touch solution supplier and designs. AMT designs, develops and supplies an extensive range of PCap touchscreen solutions for diverse transport industry applications including trains, buses, electric vehicles, construction plant, airborne systems, utility vehicles and marine craft.
Display solutions and embedded systems provider, Review Display Systems supplies and supports a wide range of AMT PCap touch solutions and associated peripheral components. Offering technical and engineering support, Review Display Systems has experience of designing and developing fully integrated touchscreen-based embedded systems for a wide range of application environments including in-vehicle and transport systems.