As a clumsy person, I’ve shattered my phone screen an unfortunate number of times over the years. Screen protectors are necessary for people like me, but you might not realize they’re far from the only type of essential optically clear adhesive.
Engineers design optically clear adhesive designs specifically to function without being seen.
Before you build your latest product, you’ll want to ensure it has the optical clarity it needs. As a flexible material converter, we’ve used a range of optically clear adhesive tapes for our customers’ projects.
As you read through these factors, you’ll learn what to watch out for in components made of optically clear adhesive tape.
What is an Optically Clear Adhesive?
Optically clear adhesives (OCAs) hold surfaces together while remaining transparent.
The primary purposes of an optically clear adhesive tape are to act as a transparent bond holding two substrates in place or protecting a screen from accidental damages. Optically clear adhesive tapes are used in applications like screens, monitors, backlight assemblies, and testing kits.
WHICH TAPES ARE OPTICALLY CLEAR?
Most optically clear adhesive tapes are transfer tapes: thin adhesive film tapes with release liners.
The most common optically clear adhesive is acrylic due to its resistance to color degradation, such as yellowing, over a long period.
Occasionally, you might encounter a silicone optically clear adhesive for more sensitive applications, but most optically clear tapes are acrylic transfer tapes.
EXPLAINING THE LEVELS OF OPTICAL CLARITY
There are different levels of optical clarity depending on the needs of a product. For example, the transparency needed for packing tape is likely far below the standard for any touchscreen protector.
- Class I: This is the highest standard of optical clarity and aesthetic appeal. (handheld device lenses, optical instrumentation, and displays).
- Class II: This designation is used where a highly aesthetic, quality product is desired (printed labels, decorative features, and permanent device applications).
- Class III: This title applies when aesthetic concerns are secondary to the product's functionality (packaging, protective masking, and parts that aren’t visible on the final product).
The higher the optical clarity required, the more expensive your material will be. In addition, a clear view means stricter error standards, which will lead to a higher quality control cost.
3 Optically Clear Adhesive Factors to Keep in Mind
As the product developer, you’ll want the most suitable tape for your project, but part of that choice is taking price and manufacturability into account. Let’s go over some of the common pitfalls of optically clear adhesive tape.
SELECTING THE RIGHT MATERIAL
One of the biggest questions when choosing optically clear adhesive is: do you need it?
There are multiple levels of optical clarity, and the vast majority of projects don’t require the Class I OCA we mentioned above. In fact, when customers come to us with clear designs, we often recommend near-optically clear materials.
Near-optically clear adhesives will degrade in color slightly over time, whereas optically clear adhesives resist discoloration entirely.
Because the difference in usability is often slight, but the cost is far reduced, many businesses benefit financially from using near-optically clear tape rather than OCA.
PROPER MANUFACTURING ENVIRONMENT
Maintaining a proper manufacturing environment is a crucial aspect of working with optically clear adhesive tape. Yet, how do you know your manufacturer follows the guidelines to reach these standards?
Not every optically clear component needs to be built in a cleanroom. Still, for those affected by contaminants like dust, dirt, hair, or other particles, the rigorous filtering process of an ISO 7 standard cleanroom will keep them clean.
QUALITY CONTROL PROCESS
Building optically clear designs is essentially the same as working with transfer tapes, except there’s more importance placed on avoiding bubbles.
Air bubbles trapped during adhesive lamination can cause unwanted distortions in the final product, so quality inspections often focus on finding bubbles and other imperfections.
Any scratches, digs, or haze in an adhesive product are considered defects. It’s also crucial to consider dust, dirt, hair, and other contaminants during the quality control process.
Using Optically Clear Adhesive Tape
Choosing your optically clear adhesive tape is only the first step of the production process.
When you order optically clear components, you’ll want to ensure you’re sourcing parts from trusted sources who manufacture pieces accurately to your specifications.
In addition, you’ll want to use a converter with experience sealing and shipping OCA parts inside impermeable membranes to protect them from moisture damage and other costly mistakes.
Do you want to manufacture an optically clear part design? Consider reaching out for a flexible material consultation about your component so you can create accurate parts with high levels of manufacturability.
If you have any questions about optically clear tape applications, feel free to contact us or continue reading about them.