Advantages of the DINGTouch EMI-shielded PCAP touch screen

Overview of EMI-Shielded PCAP touchscreen Technology

EMI (Electromagnetic Interference) shielded PCAP (Projected Capacitive) touchscreens are based on standard projected capacitive touch technology. They incorporate a specialized conductive shielding layer—such as a metal mesh, ITO conductive film, or conductive fabric—into the touchscreen structure to reduce the impact of electromagnetic interference on touch signals while preventing the touchscreen itself from emitting interference that could affect surrounding devices.

This technology is widely used in industries with strict electromagnetic compatibility (EMC) requirements, such as medical equipment, military electronics, aerospace, industrial automation, and high-precision testing instruments.

Working Principle

Standard PCAP Principle

• Transparent conductive electrodes are arranged in an X/Y grid on the touchscreen glass, detecting finger position through changes in the electric field.

• The touch controller continuously scans and analyzes signal changes, outputting the touch coordinates.

Adding EMI Shielding Layer

• A conductive mesh or transparent conductive film is added between the cover glass and the touch sensing layer, or on the back of the touch layer.

• Once grounded, the EMI shield absorbs or reflects high-frequency electromagnetic waves, reducing the likelihood of external interference affecting the touch circuitry.

Two-Way Protection

• Prevents external EMI from interfering with touch signals, enhancing touch stability and reducing drift or false touches.

• Prevents high-frequency noise generated by the touchscreen from affecting surrounding sensitive equipment—critical in medical and military applications.

Key Technical Features

Typical Layer Structure

The EMI shielding layer is grounded via conductive silver paste or copper foil to ensure effective shielding.

EMI Shielding PCAP touchscreen Structure:

Outer Cover Glass: Typically tempered glass, 0.5–1.1mm thick.

Provides scratch and impact protection and serves as the direct contact surface for touch operations.

Transparent Conductive Layer (ITO or Metal Mesh): The key electrode layer for projected capacitive touch, forming an X-Y capacitive sensing grid that detects touch by sensing tiny changes in charge from a finger.

EMI Shielding Layer: Located inside or on the back of the touchscreen.

Can be in the following forms:

Metal Mesh Layer: A fine metal mesh embedded between the inner or outer layers of glass.

Conductive Film (ITO or Conductive Coating): Conductive fabric or mesh.

Purpose: Blocks external electromagnetic interference (EMI), reducing false touches, touch drift, and noise.

Touch Controller (IC):

For example, GT911, ILITEK, etc.

Responsible for X-Y electrode signal acquisition, filtering, touch point identification, and multi-touch processing.

LCD or TFT Display Module: EMI The shielding layer is typically located between the touchscreen and the display. The display outputs the image, and the touchscreen and EMI shielding layers work together to ensure operational accuracy.

Backlight: Provides illumination for the LCD screen. EMI shielding also prevents interference from the backlight driver circuitry.

Operating Principle:

Touch Detection:

When a finger approaches or touches the screen, the projected capacitive grid undergoes a tiny charge change.

This capacitance change is captured by a controller (IC).

Signal Processing:

The controller filters and removes noise from the capacitance change.

The EMI shielding layer reduces external interference signals (such as strong electromagnetic fields from motors, radios, and industrial equipment).

Coordinate Output:

The controller transmits the processed touch coordinates to the main control board via I2C, USB, or SPI.

The main control board then performs the corresponding action (cursor movement, click, swipe, etc.).

Applications

Medical Equipment

• Ultrasound devices, ECG machines, vital signs monitors, etc., avoiding interference with pacemakers or other life-support equipment.

Military & Aerospace Electronics

• Radar terminals, tactical command systems, flight control panels, etc., ensuring stable touch performance in strong electromagnetic environments.

Industrial Automation

• High-voltage variable-frequency control cabinets, robotic operation terminals, preventing interference from high-power motors or inverters.

Precision Testing & Measurement Equipment

• Prevents EMI from affecting highly sensitive sensors or measurement instruments.

Advantages of DINGTouch EMI-Shielded PCAP touchscreen

• Professional Material Selection: Offers a variety of shielding solutions, including ITO film, metal mesh, and copper mesh.

• Customizable Options: Supports sizes from 2.8'' to 65'', with square, round, or custom shapes.

• High Transparency & Low Reflection: Maintains display quality while reducing reflectivity for improved outdoor visibility.

• Reliability Verification: Passes rigorous EMC, ESD, shock, and humidity/heat testing.

• Industry Experience: Successfully mass-produced projects in medical, military, and industrial control sectors.