As display technology continues to evolve, miniaturization has become a key challenge—especially for wearable devices. While rigid PCBs are commonly used in larger devices like TVs and computers (where space is not an issue), flexible PCBs (FPCBs) are better suited for compact, space-saving designs found in smartwatches, fitness bands, and other wearables.
FPCBs allow conductive pathways and components to be placed on a bendable substrate, which helps reduce both weight and volume in product design.
🔍 Application Overview
This inspection case focuses on solder pad detection on flexible PCBs used in wearable devices.
🧪 Measurement Target:
A flexible PCB sample with the following characteristics:
Highly reflective surface
Transparent coating layer
These features make it difficult to inspect using traditional optical methods. That’s why we use 3D Line Chromatic Confocal Sensor – HPS-LCX3000, which is ideal for high-reflective and transparent materials.
📐 Measurement Tasks
The inspection system is designed to detect and measure the following:
Pad area
Pad spacing
Bump height
Pad number recognition (ID marking)
✅ Requirements:
High accuracy
High speed
Suitable for transparent and reflective surfaces
⚙️ Technology Used
We used the HPS-LCX3000, a 3D line chromatic confocal sensor with:
Z-axis repeatability: 0.4 μm
X-axis resolution: 4.9 μm
Non-contact, high-precision 3D scanning
Excellent material adaptability: transparent, mirror-finished, and high-gloss surfaces
A single scan provides detailed 2D/3D data for multiple measurement tasks.
📊 Result
Using the HPS-LCX3000, all required features—pad area, gap, height, and numbering—were successfully measured with high precision and efficiency.
📦 Sensor Highlight
HPS-LCX Series is based on chromatic confocal technology and offers:
High-speed scanning
High imaging resolution
Compatibility with difficult materials like transparent or reflective surfaces
Ideal for applications in wearable electronics, semiconductors, and precision engineering.
