How Conber Plasma Cleaning Removes OCA Residue from LCD Glass

Customer profile

A display module and touchscreen assembly factory in the Philippines, supplying LCD glass to consumer electronics and industrial device brands across Southeast Asia.

The challenge: OCA residue was killing first-pass yield

During lamination and rework, Optically Clear Adhesive (OCA) kept leaving residue on the LCD glass surface. When the adhesive was not completely removed, the next bonding step produced bubbles, uneven adhesion, and visible contamination — forcing operators to scrap panels or send them through slow manual rework. The factory ranked OCA-related defects among its top three yield killers. Manual cleaning with solvents was inconsistent, slow, and hard to control.

The solution: Conber atmospheric plasma cleaning

After reviewing the customer's process, Conber recommended its atmospheric plasma cleaning machine. The system treats the glass surface with plasma, which breaks down thin organic residue such as OCA films and activates the surface for better adhesion in the next bonding step.

The machine works as shown in the video: the workpiece moves on the conveyor while the plasma nozzle scans across the surface from left to right, delivering consistent treatment across the full area. The demo video uses a PCB to show the scanning process — the same principle applies to LCD glass and other flat substrates.

Key features that matched the customer's needs:

• Non-contact cleaning — no mechanical scrubbing, no scratches on sensitive glass.
• Dry process — eliminates solvent consumption and the associated ventilation and waste-handling costs.
• Inline-friendly design — integrates with the existing conveyor line without major layout changes.
• Repeatable treatment — operators no longer depend on manual wiping judgment.

Plasma treatment is designed for thin-film OCA residue. For thick or aged adhesive layers, mechanical or chemical removal is recommended first, followed by plasma cleaning to finish the surface.

The results

After deployment, the factory reported visible improvements in the cleaning and lamination stages:

• 20% reduction in OCA-related defects at the bonding step, based on a 4-week comparison against baseline production data.
• Faster rework turnaround — plasma treatment shortens pre-bonding preparation time from 8 minutes to 3 minutes per panel.
• Eliminated solvent handling in the cleaning step, improving workplace safety and reducing consumable costs.
• Higher process stability, freeing operators to focus on other quality tasks.

"The plasma cleaner solved a problem we had been fighting with manual methods for months," said the factory's process engineering manager. "The glass comes out clean and ready for bonding every time."

Why plasma cleaning works for OCA residue

Plasma treatment is a surface-level process: it removes thin organic contamination and modifies the glass surface energy without damaging the substrate. For LCD glass, this makes it a practical complement to the bonding process — cleaning residue while improving the surface's receptiveness to the next adhesive layer.

Want to see the machine in action? Watch our demonstration video or contact Conber for a free sample test with your own panels.