Touch Sensor Adhesion in Display Devices

The touch sensor is merged with the encapsulation layer structure, where the encapsulation layer serves dual purposes: protecting the organic light emitting element and serving as the base for the touch sensor. The insulating layer is integrated into the encapsulation structure, eliminating the need for separate thick protective layers, thereby achieving touch functionality while minimizing thickness and size increases.

The encapsulation layer is designed to perform multiple functions simultaneously: it protects the organic light emitting element from environmental damage, provides structural support for the touch sensor, and serves as the substrate for the insulating layer and passivation layer. This multi-functionality reduces the overall number of separate components needed, thereby reducing thickness and size.

Concave portions are formed at specific locations in the insulating layer where adhesion reinforcement is needed. These localized concave features increase the contact area between the passivation layer and the underlying structures only at critical points, rather than requiring a uniform increase in thickness throughout the entire device. This localized approach maintains reduced overall thickness while improving adhesion where necessary.

Instead of increasing adhesion area in the planar dimension (which would increase size), the patent utilizes the vertical dimension by forming concave portions that extend downward into the insulating layer. This creates additional surface area for adhesion in the depth direction, allowing improved bonding between layers without increasing the device's footprint or overall thickness.