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PCAP Touch Scren made in China: 21.5 Inch USB G+G 10 Points PCAP Capacitive Touch Scren Panel

PCAP Touch Scren made in China: 21.5 Inch USB G+G 10 Points PCAP Capacitive Touch Scren Panel
Model WTY215599A01
Size 21.5 Inch
Interface USB
Structure G+G
Resolution 1920×1080
Hardness 6H
Transparency ≥82%
Aspect Ratio 16:9
Working Voltage 5V
Touch Points 10 points
Viewing Area (mm) 476.00*267.70
Outline Dimension (mm) 524.60*311.80
Operating Temperature -20ºC~+70ºC
Storage Temperature -30ºC~+80ºC
Support System Windows, Android, Linux etc
Application Fields Industrial Control, Home Automation, Medical Device, Self-service Terminal etc

HOW PCAP Touchscreens Work?

A Projected Capacitive Touch (PCT; also PCAP) technology consists of an insulator such as glass, which is coated with a transparent conductor, like ITO (indium tin oxide). The user’s finger conducts electricity, so touching the surface of the screen results in a distortion of the screen’s electrostatic field; that distortion is measurable as a change in capacitance.

In other words, a capacitance-based sensor is a circuit designed to sense touch by coupling with the electrical fields; touch causes the capacitance of the circuit to change.

Different technologies may be used to determine the location of the touch; the location is then sent to the controller for processing.

Read output from sensing points, producing and analyzing the touch data
Then compare the current data to past data and perform actions based on the comparison
Additionally, receive and filter the raw data, generate gradient data, calculate boundaries and coordinates for each touch region, and perform multipoint tracking.


Advantages of PCAP

Work in extreme weather conditions if using an appropriate touch IC controller
Resistant to liquids and dust etc
Responsive to the lightest of touches
Resistant to impact damage and scratches
Supports gesture/multi-touch functionality
Can work with gloved hands

Disadvantages of PCAP

Cost more than other types of touch technology
More sensitive to Electromagnetic Interference (EMI)
Mechanical integration needs to be more considered when using PCAP


What is the technology behind PCAP?

Custom-designed PCAP touch screens are becoming a primary choice for high-tech devices today. While older forms of touch screens use variance in electrical resistance or breaking of light beams to detect touch, most touch screens in production today rely on the principle of projected capacitance. What does this mean? That the touch screen is able to carry an electric charge.

A projected capacitive touch screen usually includes a front layer of glass with a matrix of conductive elements behind it. These elements are made from electrically conductive materials such as silver, copper, carbon, or indium tin oxide (ITO), which is a very common choice today. They are arrayed in X and Y layers, with a layer of insulation between them.

The conductive matrix is then connected to the specially designed touch controller. The controller injects an electrical charge into the matrix, and the monitor monitors the elements of the matrix for any changes. When a finger or stylus approaches the front of the touch screen, a change happens in a capacitive field – it’s generated within the matrix, but right behind the front glass.

The touch controller should be sensitive enough to detect such a change and identify the areas or elements of the matrix that are experiencing the greatest change. It can then triangulate the touch position within layers of the matrix and transmit the data in the form of X-Y correlates to the host machine. This works just like a mouse or a mousepad that moves the cursor around a display.