Silicone optical bonding materials at CES Asia
At CES Asia 2019, Dow Performance Silicones, unveiled two new optical bonding solutions for automotive and consumer displays exposed to harsh environmental conditions. They include DOWSIL VE-2003 UV Optical Bonding Material, designed to bond a glass or plastic display cover and touch panel to the LCD or OLED display module, and DOWSIL VE-4001 UV Electrode Protective Resin, which protects electrodes on the display module.
Jayden Cho, Global Consumer Marketing Segment Leader, Dow Performance Silicones, said: “As interactive displays in connected vehicles play an increasingly vital role in safety, navigation and entertainment, consumers expect an exceptional user experience. These displays must sustain their performance over the vehicle lifespan, under the demanding conditions of automotive interiors.
“DOWSIL VE Optical Bonding Materials deliver better readability, visibility and reliability compared to traditional organic materials, support new designs and easily adapt to existing optical bonding processes. Dow will continue to address our customers’ demands for higher-performing optical bonding solutions to meet the requirements of tomorrow’s increasingly sophisticated displays.”
These robust silicone-based materials represent the newest generation of DOWSIL VE Series optically clear resins, whose excellent optical properties help automotive and consumer displays deliver exceptional performance. Their benefits include high transmittance, low haze, minimal yellowing and superior reliability, even when subjected to temperature extremes, high humidity and prolonged UV exposure.
The automotive display market is projected to grow at a CAGR of over ten percent through 2025, with 350 million units globally expected to ship by that date. Top design trends include the integration of touchscreens, larger displays, curved screens and heads-up displays.
Reliable optical bonding
Environmental reliability test conditions in the automotive industry, including high-temperature degradation, thermal shock and humid heat constant, have become more stringent in recent years, calling for increasingly reliable optically clear resins.
In direct response to this challenge, Dow developed the new DOWSIL VE Series materials. DOWSIL VE-2003 UV Optical Bonding Material is a transparent, solventless, one-part UV-curable solution used to bond a cover window and touch panel made from glass or plastic, such as polymethyl methacrylate (PMMA) or polycarbonate (PC), to the display module.
It is engineered to resist degradation and yellowing from ultraviolet (UV) exposure and from high and low temperature extremes and humidity. The material delivers consistent optical transmittance greater than 99 percent before and after reliability testing.
DOWSIL VE-2003 UV Optical Bonding Material offers excellent adhesion, self-levelling flowability, low modulus to avoid mura effect, and low shrinkage (less than one percent) for dimensional stability – especially in larger displays. It can cure to an extremely soft material which helps provide cushioning and stress relief for delicate components.
Benefits of an all-silicone solution
Using a silicone-based solution for both electrode protection and optical bonding optimises reliability of display modules, whose mechanically sensitive electrodes can be affected by moisture, heat, impact, and especially UV light. It also avoids incompatibility issues arising from the combination of silicone optical bonding with organic electrode protective resin (EPR). This can lead to failure in solar testing and cause haze, yellowing and softening of the silicone OCR under high temperatures (up to 105°C) and UV levels in automotive interiors.
To offer the industry a compatible, silicone-based EPR for use with DOWSIL VE-2003 UV Optical Bonding Material, Dow developed DOWSIL VE-4001 UV Electrode Protective Resin. This new solution offers high reliability including consistent hardness and adhesion before and after testing, thanks to its low volatility. The cured material provides stress relief for sensitive components.
DOWSIL VE-4001 UV Electrode Protective Resin is a translucent, one-part, UV-curable silicone resin designed for liquid-based bonding processes and is available worldwide.