Capacitive Touch Screens Explained

29 Feb.,2024

 

 

Capacitive touch is the norm today and is more or less used in every smartphone or tablet available. Projected capacitive touchscreen technology (PCT or PCAP) is a capacitance system that delivers a sensitive, accurate multi-touch interactive experience (it can register simultaneous touch points on the capacitive layer). Basically, a projected capacitive touch screen is a grid of tiny, transparent electrodes. An X-Y grid is formed either by etching one layer to form a grid pattern of electrodes, or by etching two separate, perpendicular layers of conductive material with parallel lines or tracks to form the grid; comparable to the pixel grid found in many liquid crystal displays. Everywhere the grid lines overlap, a capacitor is created. The human body is an electrical conductor and when you touch the screen with your finger, the sensor changes the local electric field which reduces the mutual capacitance. The capacitance change at every individual point on the grid can be measured to accurately determine the touch location by measuring the voltage in the other axis.

Depending on the implementation, a stylus can be used instead of, or in addition to, a finger. This is common with point of sale devices that require signature capture. Gloved fingers may or may not be sensed, depending on the implementation and touch screen settings. Because the top layer of a PCT is glass, PCT is a more robust solution versus resistive touch technology. It responds to a light touch and can be designed with a seamless, zero-bezel design.  Projected capacitive touchscreens combine high resolution with excellent transparency, making it an excellent choice for most public venues including retail and hospitality. Whether activated by fingers or gloved hands, it consistently delivers a fast, accurate, drift-free touch response.

 

Advantages of Capacitive Touch Screen

          - Fast, sensitive touch response with excellent dragging performance

          - Multi-touch support for gestures such as pinch-to-zoom, etc.

          - High Durability

          - Excellent optical transparency and color fidelity

          - Stable, no-drift performance - no calibration required

          - Recognizes touch from ONLY a finger or a capacitive stylus

          - Touch performance is generally unaffected by everyday use and mishaps such as dirt, dust, condensation, liquid spills, contaminants or cleaning solutions.


Disadvantages

          - Projected capacitive is more expensive than resistive technology


          - High levels of electronic noise can reduce accuracy.


          - Recognizes touch from ONLY a finger or a capacitive stylus


          - Conductive smudges and similar interference on the panel surface can interfere with the performance. Such conductive smudges come mostly from sticky or sweaty finger tips.



Applications

          - Point-of-Sale terminals (POS)
          - Retail kiosks
          - Gaming /amusement
          - Hotels
          - Corporate offices and conference rooms

 

    Touch Products

              - Special order in 7” products

              - 10.1” – Magic Touch, Magic Touch Deluxe

              - 10.1" Mimo Adapt and POSPAD

              - Available on all open frame monitors

     

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