The Vital Role of FOG in TFT LCD Manufacturing

The Vital Role of FOG in TFT LCD Manufacturing

The Film on Glass (FOG) process, a pivotal step in manufacturing high-quality Thin-Film Transistor Liquid Crystal Displays (TFT LCDs). The FOG process involves bonding a Flexible Printed Circuit (FPC) to a glass substrate, enabling precise electrical and physical connections critical to display functionality. Any defects in this step—such as cold solder, shorts, or detachment—can compromise display quality or render the module unusable. Wisevision’s refined FOG workflow ensures stability, signal integrity, and long-term durability.  

Key Steps in the FOG Process

1. Glass & POL Cleaning

The TFT glass substrate undergoes ultrasonic cleaning to eliminate dust, oils, and impurities, ensuring optimal bonding conditions.  

2. ACF Application

   An Anisotropic Conductive Film (ACF) is applied to the glass substrate’s bonding area. This film enables electrical conductivity while shielding circuits from environmental damage.  

3. FPC Pre-Alignment

Automated equipment precisely aligns the FPC with the glass substrate to prevent misplacement during bonding.  

4. High-Precision FPC Bonding  

 A specialized FOG bonding machine applies heat (160–200°C) and pressure for several seconds, creating robust electrical and mechanical connections via the ACF layer.  

5. Inspection & Testing

Microscopic analysis verifies ACF particle uniformity and checks for bubbles or foreign particles. Electrical tests confirm signal transmission accuracy.  

6.Reinforcement  

UV-cured adhesives or epoxy resins reinforce the bonded area, enhancing resistance to bending and mechanical stress during assembly.  

7. Aging & Final Assembly

Modules undergo extended electrical aging tests to validate long-term reliability before integrating backlight units and other components.  

Wisevision attributes its success to rigorous optimization of temperature, pressure, and timing parameters during bonding. This precision minimizes defects and maximizes signal stability, directly improving display brightness, contrast, and lifespan.  

Based in Shenzhen, Wisevision Technology specializes in advanced TFT LCD module manufacturing, serving global clients across consumer electronics, automotive, and industrial sectors. Its cutting-edge FOG and COG processes underscore its leadership in display innovation.  

For further details or partnership opportunities, please contact lydia_wisevision@163.com