What is OCA?

OCA (Optically Clear Adhesive) is a substrate-free, solid double-sided adhesive tape. It is formulated from optical acrylic adhesive into a baseless material, with a release film applied to both sides. Because of its tape-like form, it is also referred to as optical tape or optical double-sided tape.

OCA is widely used in standard flat-panel bonding where high precision and uniform thickness are required.

Advantages of OCA

• High cleanliness, light transmittance (>98%), and low haze.
• Uniform adhesive layer thickness with excellent flatness.
• High adhesion strength and broad material compatibility (soft-to-soft, soft-to-hard).
• Fast production speed and minimal adhesive overflow.

Disadvantages of OCA

Despite its benefits, OCA faces challenges with the rise of flexible and large-size displays:

• Prone to bubble formation during lamination; bubbles may rebound after degassing.
• Poor flowability makes it unsuitable for uneven surfaces or framed LCD panels.
• Difficult to apply to curved surfaces and large-format displays.
• Difficult to rework, leading to high labor costs.
• Adhesive strength degrades at high temperatures.

What is OCR/LOCA?

OCR (Optical Clear Resin), also known as LOCA (Liquid Optical Clear Adhesive), is a liquid-form optical adhesive. Upon curing (typically UV or thermal), it becomes colorless, transparent, and exhibits excellent resistance to yellowing and low shrinkage.

OCR is the preferred choice for complex structures, large sizes, and curved surfaces where traditional tape cannot reach.

Advantages of OCR/LOCA

• High versatility: One formulation can fit multiple products.
• Superior fluidity and gap-filling performance, even on uneven surfaces.
• No size restrictions, making it ideal for large-format bonding.
• Excellent for curved surfaces and complex structural bonding.
• High bonding yield and excellent reworkability.
• Minimal temperature sensitivity and superior long-term stability.

OCA vs. OCR/LOCA: A Side-by-Side Comparison