Optical Bonding
TFT displays with touch and cover lens.
In addition to pure image quality, mechanical stability, readability and robustness play an essential role in the service life of display systems.
Optical bonding combines the TFT panel, touch sensor and cover glass to form an optically and mechanically optimized unit. An essential component that is crucial for the user-friendliness, reliability and value of your device.
Stable bond
A display without bonding has air gaps between the layers (TFT, touch, cover glass). This leads to reflections, reduced contrast and reduced readability in bright ambient light. In addition, dust or moisture can penetrate the air gaps more easily.
Optical bonding prevents these error risks: The gaps are filled with a transparent adhesive or the layers are directly bonded.
Advantages
This is how optical bonding increases performance.
- higher readability by reducing light reflections and increasing contrast
- mechanical stability against impacts, vibrations and temperature fluctuations
- protection against environmental influences such as dust and moisture
- optimized touch performance, as no air gap distorts the detection
Technologies
LOCA
Liquid Optically Clear Adhesive
LOCA uses an optically clear liquid adhesive. This is applied between the TFT, touch and/or cover glass and then fixed by UV or heat curing.
Advantages:
excellent optical properties, completely fills even uneven surfaces, very good light transmission
Disadvantages:
complex process, longer cycle times, greater effort for rework
Typical areas of application:
high-quality industrial and automotive displays with high demands on readability and robustness
SOCA
Solid Optically Clear Adhesive
SOCA is a solid, pre-applied adhesive film (OCA film). This is laminated between the layers. The process is faster and cleaner than with LOCA. Because the process does not use liquid materials.
Advantages:
clean process, short cycle times, simple handling process
Disadvantages:
lower tolerance compensation capability with uneven surfaces, limited long-term stability in very harsh environments
Typical areas of application:
consumer electronics, industrial application with medium requirements
Air Bonding
With air bonding, the touch sensor and cover glass are only glued at the edge. An air gap remains between the layers.
Advantages:
cost-effective, simple, fast production
Disadvantages:
significantly higher reflection, limited readability in sunlight, lower robustness
Typical areas of application:
cost-optimized applications without high outdoor or rugged requirements
What fits?
The choice of bonding technology depends heavily on the requirements of the application:
While air bonding can be used for price-sensitive projects, SOCA offers a good compromise between costs, process reliability and optical quality. LOCA is the premium process for scenarios that demand maximum readability, robustness and longevity.
Feel free to discuss with us which technology works best for your framework conditions.
Quality-determining
More than a technical detail.
Optical bonding determines the user-friendliness, reliability and value of a device: It improves the readability of displays through reduced reflections and higher contrast values. At the same time, it increases stability and resistance to impacts and environmental influences. And prevents the ingress of dust and moisture between the display and glass.
A relevant component for your development concept.
Your desired display?
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