User Manual
Appendix B
PCAP Touchscreen
ECDIS Marine Display
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Appendix B PCAP Touchscreen
This section includes information on projected capacitive touchscreen (PCAP), its
technology and specifications.
B1 Technology Overview
Projected Capacitive Touch (PCAP) technology is a variant of capacitive touch
technology. All PCAP touch screens are made up of a matrix of rows and columns of
conductive material, layered on sheets of glass. Projected capacitive technology enables
touches to be sensed through a protective layer in front of a display, allowing touch
monitors to be installed behind store windows or vandal-resistant glass. In addition, the
surface material is glass, which is scratch-resistant, durable, and reliable in harsh
environments.
The operational theory of a PCAP touch screen begins with two patterned Indium Tin
Oxide (ITO) layers under a glass substrate cover which create a X-axis and Y-axis electric
field. These electric fields project above the glass surface between adjacent ITO traces.
When a finger approaches the glass surface, a new balance in the electric field will be
established between the finger and the corresponding X-axis and Y-axis. The controller
IC will locate the ITO traces exhibiting capacitance changes to pinpoint the finger touch
accurately.
B2 Touchscreen Technical Specifications
Subject
Details
Input Method
Finger
Positional Accuracy
<1.5% of reported position in recommended viewing area.
Resolution
Touch point density is based on controller resolution.
Touch Activation Force
No minimum touch activation force is required
Light Transmission
Up to 90% per ASTM D1003-92
