Resolving LCD Display Electromagnetic Interference

Introduction: Electromagnetic interference (EMI) poses challenges during LCD display testing, affecting both power and signal lines. Resolving EMI is critical for maintaining accurate and reliable display performance.

Issues and Solutions:

1. White or Blue Screen:

• Issue: Interference on VDD or VSS causes a reset, displaying a white or blue screen.
• Solution: Add stabilizing and filtering capacitors (10uF and 0.1uF/0.01uF) near the module.

2. Erroneous Characters or Dots:

• Issue: Interference on control signals modifies register parameters.
• Solution: Shield transmission lines, change their direction, or shorten them. Use a transmission line driver.

3. Unidentified Interference Points:

• Solution: Periodically initialize registers. Close interrupt response during module operation.

Anti-Interference Measures:

1. Graphic Module Static Discharge Test:

• Solution: Switch to an organic glass shell, add a timed refreshing program to mitigate interference during discharge tests.

2. Graphic Module 8kV Discharge Test:

• Solution: Add capacitors and surge tubes to power pins, enhancing display reliability during discharge tests.

3. 4kV, 150Hz Interference Test:

• Solution: Introduce transient surge absorbers to power line interfaces for improved performance.

4. High-Voltage Electromagnetic Interference on Switchgear:

• Solution: Switch to an isolated power supply and implement various circuit adjustments.

5. Long Connection Line Issues:

• Solution: Adjust signal waveforms, shorten lines, and introduce Schmitt trigger circuits for reliable performance.

• Conclusion: Addressing EMI involves strategic hardware adjustments, shielding, and grounding practices to ensure LCD display modules perform reliably across diverse environments.