Technical Glossary Optical Clear Resin (OCR)

[Optical Clear Resin (OCR)]

An OCR is a liquid optical bonding material, which is injected between the touch panel and the LCD, then cured by heat or UV light.
Acrylic is the most common OCR, however, when more durable material are required, such as in automotive applications, silicone OCRs are also popular.
OCRs have several advantages over OCAs, including reliable black print gap filling, customizable thickness, little danger of delay bubbles caused by contamination, and low material costs. On the other hand, they are not without issues. Bonding equipment (injection and curing equipment) is expensive. The bonding process is difficult, as thickness precision and prevention of spillage during injection present unique challenges. Mottling in the LCD due to curing shrinkage is also known to occur.
Hybrid OCRs have been developed to address these issues. Hybrid OCRs are extruded by a slit die at a certain thickness and are half-cured with a UV lamp. The materials are bonded like OCAs and then receive secondary curing. The bonding process is more complex, but issues such as shrinkage, imprecise thickness and spillage are avoided.