Transparent adhesives are widely used across industries such as electronics, automotive, medical devices, furniture, and consumer products. These glues not only improve bonding efficiency but also preserve the aesthetic appearance of the product thanks to their transparency.
However, detecting transparent glue during manufacturing is challenging. Traditional vision systems often fail to spot defects, uneven distribution, or missing adhesive — simply because the material is see-through.
One of the most challenging materials to inspect visually is black rubber.
The Challenge
Due to the light-transmitting nature of transparent adhesives, conventional visual inspection systems struggle to:
Identify missing or insufficient glue
Evaluate glue thickness
Detect surface defects like bubbles or uneven spreading
This creates risks in product quality, reliability, and sealing performance — especially in smartphones, displays, or precision assemblies.
Our Solution: Chromatic Confocal 3D Line Sensors
To overcome these limitations, Hypersen has developed advanced 3D line chromatic confocal sensors, including the HPS-LCF1000 and HPS-LCX series.
These sensors use chromatic confocal technology, a method that captures 3D surface profiles with extremely high accuracy — even on transparent or highly reflective materials.
Key benefits:
✅ Accurate glue height and width measurements
✅ Reliable inspection even on transparent, black, or shiny surfaces
✅ No interference from material reflectivity or color
✅ Real 3D surface profiles for defect detection and analysis
Test Case: Transparent Glue on Smartphone Glass
🛠 Inspection Setup
Application: Detect adhesive applied to the side of a smartphone glass panel
Goal: Measure glue thickness, shape, and detect surface defects
Sensor used: HPS-LCF1000
🔬 Sensor Specs
Scanning line length: 5.9 mm
Z-range (height): 3 mm
Data points per line: 2048
Z-axis repeatability: 0.1 μm
Thanks to these specs, the sensor delivers ultra-precise 3D data, enabling detailed analysis of glue distribution and uniformity.
How It Works
The chromatic confocal principle uses specially designed optics to separate different wavelengths (colors) along a depth axis. Each color focuses at a different distance — so by detecting which wavelength is reflected, the sensor can determine the exact height at that point.
The system is immune to light intensity variations, making it perfect for materials like:
Transparent glue
Glass or sapphire
Liquids
High-gloss or black rubber
Inspection Results
By tilting the sample during scanning, the system captures a complete 3D profile of the glue line and underlying glass. The resulting data clearly shows:
Glue thickness and coverage
Gaps or missing glue
Bubbles or uneven application
This enables precise process control and improved product quality in real-time.
Applications Across Industries
This inspection solution is already being used in:
📱 Electronics: Display panel assembly, smartphone bonding
🚗 Automotive: Component sealing, adhesive application checks
🧪 Medical and Lab: High-precision bonding for instruments and optics
As the demand for high-quality transparent bonding grows, chromatic confocal 3D sensing provides a reliable, high-performance solution — future-proofing your inspection process.
