What's the difference between OCA Bonding and Water Glue Bonding of LCD Touch Display?

——Shenzhen Xinlilai Touch Technology Co., Ltd. Technology Sharing
 

In the field of touch screen manufacturing, OCA (optical adhesive) bonding and water-based adhesive bonding are two mainstream full bonding processes of touch panel and LCD display. As a source factory specializing in the touch display industry for 15 years, Xinlilai Touch will take you to understand the essential differences between these two processes from the perspective of technical characteristics today.
 

1、 Material characteristics: Solid film vs liquid flow
OCA bonding uses pre formed solid optical adhesive film, which is made of optical grade acrylic material with a stable refractive index (usually 1.48-1.51) and can achieve a transmittance of over 93%. Water glue (LOCA) is a liquid optical glue that needs to be filled in gaps through dispensing technology. It has fluidity before curing and requires higher equipment accuracy.
Our factory's actual test data shows that under the same specification glass substrate, the OCA bonding thickness tolerance can be controlled within ± 0.025mm, while the water-based adhesive process may experience thickness fluctuations of ± 0.05mm due to curing shrinkage.
 

2、 Process complexity: dust-free environment vs process control
OCA bonding needs to be completed in a Class 10000 dust-free workshop, using vacuum defoaming equipment for one-time pressing, with a yield rate of over 98%. The water-based adhesive process requires multiple steps of dispensing diffusion UV curing, and strict control of adhesive volume, bubbles, and overflow issues is required during the process. The batch production yield rate is usually in the range of 90-95%.
However, for curved or irregular screens (such as circular or polygonal), the fluidity of water-based gel becomes an advantage, as it can perfectly fill irregular gaps. This is also the reason why smart wearable devices often use water-based gel.
 

3、 Terminal performance: aging resistance vs seismic resistance
According to the 2000 hour high temperature and high humidity test conducted by Jingxinlilai Laboratory:
OCA adhesive products have no obvious yellowing, and the peeling force attenuation is less than 8%
There may be slight rainbow patterns on the edges of water-based adhesive products, but they perform better in drop tests (with a 15% increase in pass rate for 1.2m drops)
 

Purchase suggestion:
OCA is the preferred choice for commercial display devices that pursue display effects and lifespan
For car/industrial control equipment that requires frequent vibration or large temperature differences, it is recommended to use water-based adhesive
 

We offer customized services for two different processes of touch panel and LCD display. Follow Xinlilai Touch for more practical touch display technology!