What You Can Do with Crystal Clear Adhesives

In general, we think that adhesives are only used to bond one component to another. And although that is one of its primary functions, it is not its only function.

Adhesives can be used for tension equalizing or conducting electricity. As a matter of fact, they have multiple functions and uses that many of us never even think of, including being used as optical enhancers in some of the toughest industries.

Thinking about adhesives in this manner is sort of strange because most of us think of them as being at least a little opaque. However, some very special optically clear adhesives are used to improve transparency for industries that demand crystal clear displays.

In display bonding, a cover glass is bonded flat onto an LCD module. If adhesive is not used, an air gap is left between the cover glass and display. Touch panels can also be bonded to the display and cover glass in the same way. Having an optically clear adhesive filling the gaps improves the display’s viewing quality.

Adhesive reduces disturbing reflections from light by up to two-thirds and helps provide better color contrast. In addition to improved readability, optically clear adhesives prevent contamination from dust and condensation between the LCD. They also improve a display’s shock resistance – meaning, the display becomes more rugged and is more likely to continue to work properly after it has been dropped.

Comparison of a bonded (left) and non-bonded display half (right) (image: DELO)

Head on-crash tests have demonstrated the high strength performance of aluminosilicate glass and special adhesives. In the international ECE R21 standard test, a head-on impact of a car crash is simulated with a steel ball.

The 6.12 kg ball is dropped from a height of 2.52 m and reaches a speed of 25.3 km/h and impact energy of 152 J. Below you can see the results of the test.

A standard liquid crystal display completely splinters, while a bonded glass cover composite only bends, but does not break. These results show the durability that many engineers need for their applications.