Optically Clear Adhesives for Touch Screens


Do you appreciate the ability to clearly see messages on your phone? Or watch your in-car DVD player when riding shotgun? If so, you have encountered optically clear adhesive and may not even realize it.

Today, this adhesive is used for a wide array of electronic devices and plays a crucial role in their operation.

While this is true, you may not know what it does or what benefits it offers. Don’t worry; you aren’t alone.

However, once you learn about this innovative product, you’ll see the role it plays in your life and why it’s such an invaluable product. It is something that you may not see or encounter individually but still used daily by most people. Keep reading to learn more.

What is Optically Clear Adhesive?

Before diving into the specifics of optically clear adhesive, you need to understand what it is. Put simply; it’s a bonding technology used with display devices and touch panels to bind the plastic, cover lens, or other optic materials to the primary sensor unit or one another.

Using the adhesive helps to improve durability and optical characteristics.

 Unlike other materials, optically clear adhesives are entirely transparent and uncolored. Optically clear adhesives allow the entire surface area of a screen to bond to the device without any distortion to the graphics display. Optical clarity can be the most critical aspect of the adhesive in these applications.

We measure optical clarity in three different ways: transmittance, haze, and refractive index. Depending on your project, one may be more important, or they all may be equally important.

 The medical and electronic industries frequently use optically clear adhesive or OCA films for screen bonding. Optically clear adhesive for touch screen applications is becoming standard. 

Optical Clear Adhesive


Uses for Optically Clear Adhesive

Optical adhesives are used for an array of electronic devices, particularly the ones that have touch panels. The adhesive will bond to the touch panel and the main liquid crystal display. It also bonds any productive cover, including the leans, to the touch screen.

After the adhesive is applied to the electronic device, it is cured using ultraviolet light, moisture, heat, or a combination of these methods. This is dependent on the specifications of the project and the manufacturer. Some of the main applications include glass retarders, 3D televisions, and capacitive touch panels.

Some of the specific uses of this adhesive include:

  • Bonding of flexible-to-rigid or flexible-to-flexible optical components for touch screens, flat-screen CRTs, and flat panel displays.

  • May be used as a base film for optical components, as a screen surface protector or as a sputter coating to resist harsh chemicals and scratches.

  • Touch screens use the material to reduce flammability in medical, aerospace, and other similar, critical applications.

  • For the bonding of backlight assemblies, A/R surface treatment films, holographic optical elements, diffusers, polarizers, and many other management films located in device displays.

For electronics screen bonding, it is crucial to use tight tolerance die-cut pieces. Otherwise, the application may have excess adhesive or contaminants around the perimeter of the device. The die-cut helps to create the most reliable bond while minimizing weight.

Because of the benefits of this adhesive, it’s a popular product for use with most modern electronic devices.

Optically Clear Adhesives for Touch Screens


Advantages of Optically Clear Adhesives

The use of optical bonding helps to improve the performance of device displays. It effectively eliminates the gap between the LCD and cover glass. It typically includes an anti-reflective coating, along with anti-glare and anti-smudge treatments for the cover glass.

The Fresnel reflections from the glass, along with the adhesive, may degrade the viewability on the LCD screen. The reflection is the result of an impedance mismatch between the glass and air.

The reflections make the whites brighter but will dilute other colors, including black, which reduces overall contrast. The goal of adhesive manufacturers is to match the refractive index of glass that’s used in electronic displays to help minimize this loss. Optically clear adhesives achieve this goal and help to improve the viewing experience significantly.

Along with all the optical advantages this adhesive offers, it also helps to improve display durability. This adhesive can resist condensation and scratches. It also has an improved operating temperature range.

With touchpad devices more ubiquitous in today’s market than ever before, this increased level of ruggedness is more critical than ever before. Also, it reduces light loss because the reflection helps to extend the battery life because the device doesn’t need as much backlight.

More specific benefits offered by the use of this adhesive include:

  • Facilitates high light transmission

  • High clarity

  • Low haze

  • Non-birefringent

  • Virtually defect-free

  • High Adhesion

  • UV Protection

  • Bare ITO Compatible

  • Whitening Resistant

  • Out-gassing Resistant

  • Temperature Resistance

  • Humidity Resistance

  • Excellent Work-ability

  • Manufactured in a Cleanroom Environment

Each of these benefits is attributed to why the adhesive is so commonly used by manufacturers today.

Why Optically Clear Adhesives Are So Important

Every day you encounter these adhesives. Each day as you are wiping your phone screen or typing on it, you are interacting with the display, which uses this adhesive.

It is found on tablets, cell phones, devices used to pay for parking, ATMs, and more. The demands for this adhesive are continually growing, which makes it a valuable product. Everyone requires displays that are transparent and easy to read, regardless of the light conditions.

Modern adhesives fill the gap of air present between the display (with or without bezel) and the glass cover. When in place, as mentioned above, the layer works with refraction to reduce reflection significantly.

In addition to improved visibility, when a display is being used, the optical bonding and filling the air gap provides other advantages. This includes less space for condensation or dust on the glass display when the air around the product is humid.

Questions to Consider:

  • Will it be exposed to high temperatures and high humidity?

  • Do you need removable adhesives or permanent adhesives?

  • How concerned are you with bubbles?

    • Some film adhesives offer superior clarity with improved bubble resistance.

  • Is the thickness of the release liners essential?

  • Is it going to be used as a mounting adhesive?

    • If so, is it going to be face mounted?

Popular 3M Optically Clear Adhesives:

Understanding the Uses and Benefits of Optically Clear Adhesive

As you can see, an optically clear adhesive is a crucial part of modern electronic devices. While you may not have known much about this product in the past, you now have a clear understanding of what it is and how it works.

At Strouse, we offer die cuts for the optically clear adhesive to meet custom formats, shapes, and sizes. We can also provide you with products that include custom width rolls of tape or other custom cut parts that are on a roll, as individual pieces, or on a sheet.

If you are thinking about using Optical Clear Adhesive or Optical Clear Adhesive Films, contact us today!