Understanding the Benefits of OCA Bonding

Understanding the Benefits of OCA Bonding

Aug 6th 2022

Understanding the Benefits of OCA Bonding 

There are many ways by which the layers of a display can be held together; one of the best is OCA bonding, or optically clear adhesive (OCA) bonding, which attaches display layers together with a sheet adhesive. FocusLCDs optically transparent adhesive bonding is a revolutionary technique that enables for shorter bond lines and, as a result, thinner overall display stack-ups. To bind layers together, OCA bonding uses a dry film pressure-sensitive glue. OCA is pressure laminated to a substrate to reduce air gaps in the assembly. This can be used to join rigid components together or to join a flexible component to a solid component.

There are two unique methods by which optically clear adhesive bonding can be achieved. The first is flexible OCA bonding, which employs a roller to push out all of the air between the flexible and rigid components. The second is rigid-to-rigid bonding, in which a vacuum chamber is leveraged to remove the air between the layers to adhere to the components closely.

In either of the above OCA bonding methods, Optical clarity is maximized by eliminating any bubbles or air spaces, making OCA perfect for situations where readability is crucial, such as for healthcare or mobile information use cases. This bonding capacity is ideal for components that require a focus on limiting thickness, such as cover glass, touchscreens, and frameless LCDs. Another advantage of this method of bonding is that it does not require curing, making it quicker to manufacture than conventional bonding methods. When compared to liquid adhesives, sheet adhesives provide tighter tolerance, more uniform flat bond lines, and greater yield rates. There is no need for specialized dispensing equipment

In some use cases, LOCA or Liquid Optically Clear Adhesive can also be considered. This process is a liquid-based bonding method that binds the cover lens, plastic, or other optical materials to the primary sensor unit or each other in touch panels and display devices. These adhesives increase the optical properties as well as the durability. UV light is frequently used to harden LOCA glue. LOCA binding also offers its own advantages that OCA bonding does not, primarily that it can allow for reworkabillity, adhesion to non-even surfaces, and an even further increase in durability.

While using a separate protective glass layer is helpful, OCA bonding by itself is considered robust with features such as UV protection, as well as moisture and dust resistance. OCA bonding eliminates the likelihood of moisture or dust entering between the LCD and the glass, reducing the amount of reflecting layers, improving readability, providing UV protection for outdoor applications, and increasing the display's resilience against direct physical contact. To add even greater protection, and inexpensive option might also be to pair an OCA bonded screen with a polycarbonate or polyethylene layer as an alternate protective cover material. This method is great for use cases that do not require extreme portability, are not utilized in harsh locations, or are cost conservative. A protective cover may be put on the LCD's face, and the cover absorbs the impact rather than the display. The thickness of such a cover varies from 0.5mm to 2.0mm, with the added benefit of additional dust and moisture protection.

When you use OCA bonding for your display, it becomes more impact resistant and less vulnerable to environmental exposure like dust and moisture. OCA offers nearly unparalleled optical clarity making it a great choice for use cases that don't require any reworking of the display. FocusLCDs has a diverse product catalog that will help you reach an unmatched balance between cost and performance for your project and are available to help you figure out the products you need for protecting any design.