News | November 9, 2022

Optical Bonding Adhesives And Their Idealness In Touch Screen And Flat Panel Displays Manufacturing

Optical bonding is the protective glass glued on displays to enhance readability, especially if the installation is done in outdoor environments with high humidity. With normal displays within outdoor environments, there are many readability issues, with the common one being condensation or fog. This forms on the display's inner surfaces. Sunlight reflection is the other issue that leads to mirror images on such a display. With optical bonding, the issue can be resolved.

Adhesive types
Optical bonding involves the use of different adhesives. The most common ones are polyurethane, epoxy, and silicone. Knowing the pros and cons of each helps with the selection process. It is always important to choose your adhesives correctly to get the most out of them.

This is the most popular adhesive for optical bonding, and it has been used for decades. The main properties of silicone include thermal stability, chemical reactivity, Low conductivity, and water repulsion capability. This adhesive makes airtight seals which makes it a good solution for optical bonding.

The material is soft and can be reworked should the bonds damage over time. The only issue is that over time, debris form around the bond edges.

Epoxy can be applied as a structural glue, creating a rigid bond. This means that there is no particulate debris formation like in the case of silicone bonding. One of the main issues of using epoxy as an optical adhesive is that this bond cannot be reworked.

These types of adhesives are used in displays in polar technology and avionic technology. The main issue with using polyurethane as an optical adhesive is the yellowing that happens over time once there is light exposure. This is why most people consider it an unsuitable or obsolete option.

Optical bonding's main idea
Optical bonding involves using an adhesive within this grade to glue glass in a display. The main aim is to make the display perform better in outdoor settings. With optical bonding, there is no air gap left between the display and the cover glass.

In optical bonding glass, an anti-reflective coating is used. The main issue is readability within outdoor environments. The contrast, not the brightness, is the real issue. Contrast can be defined as the ratio of the black level to the white level. Optical bonding aims to boost the contrast ratio and reduce the amount of reflected ambient light.

The benefits
There are several benefits associated with optical bonding adhesives. They include:

  • Ruggedness: when you bond glass on display, it makes it more rugged, which is a good thing.
  • Durability: optical bonding boosts the durability of the display. This means that it is in a better position to resist dirt, stains, fluids, and scratches.
  • Condensation: optical bonding eliminates air gaps between the display and the cover glass. Because of this, moisture cannot penetrate. This means no fogging will occur.
  • Extended EMI filtering and temperature range: this can be achieved by including ITO heaters. The same mechanism can be used to add filters.
  • Better display performance.
  • An accurate and fast response time.
  • When silicone is used, it remains clear for a long time.
  • The display images are enhanced.
  • Optical adhesives can withstand public environments with high traffic.

Source: DeepMaterial (ShenZhen) Co.,Ltd