In consumer electronics, especially mobile phone manufacturing, surface cleanliness and wettability are key factors in determining the reliability of bonding, coating, and sealing. Contact angle measurement, as a rapid and intuitive inspection method, is widely used to verify material surface condition and plasma treatment effectiveness.

1. Principle

The contact angle refers to the angle formed when a liquid drop contacts a solid surface.
A larger contact angle indicates lower surface energy, poor wettability, and easy detachment of the glue or coating.
A smaller contact angle indicates higher surface energy and better wettability, facilitating bonding and coating.

2. Application Scenarios in Mobile Phone Manufacturing

Display Lamination
Before laminating a glass cover with OCA/UV adhesive, measuring the contact angle can assess whether the surface requires plasma treatment. After treatment, the contact angle is reduced, ensuring a uniform, bubble-free bond.

Housing Coating/Printing
Measure the water drop angle on plastic or metal housings to determine whether the surface energy is sufficient to support strong adhesion of coatings or inks.

Camera Module
Before bonding lenses and sensor substrates, water drop angle measurement is used to verify plasma cleaning effectiveness and prevent poor sealing due to insufficient wettability.

Waterproof Sealing
During device assembly, water drop angle measurement confirms the wettability of the glue on the phone frame and glass, ensuring a seal and meeting IP rating requirements.

3. Measurement Significance

Contact angle  measurement is not only a means of inspecting surface treatment effectiveness but also a key component of plasma process quality control. Using water drop angle data, manufacturers can:
Quantitatively evaluate plasma cleaning/activation results;
Establish process monitoring standards to ensure batch consistency;
Reduce the risk of failures such as poor bonding and coating detachment.