Optical bonding is the joining of two optical components together. However, many methods are used for contact bonding, depending on what is needed and the type of optical components being used. Adhesive contact bonding is often utilized, where the two components are fused together using a safe adhesive such as UV epoxy and polyurethane. 

However, another type of optical bonding known as optical contact bonding. There is no adhesive used in this method. There is no adhesive used in this method. Smooth glass optical components (such as the type we manufacture here) are instead fused using their adhesive forces. If the laser damage threshold is not met, then optical contact bonding is a better choice for your application than adhesive contact bonding. For instance, when used as an optical adhesive, polyurethane can yellow over time due to light. With optical contact bonding, there is no chance of adhesive damage. 

What Is the Optical Contact Bonding Process?

Depending on the need, there are many optical contact bonded processes; however, nearly all use water bonding. An extra step is used in the optical contact bonding process to create covalent bonds. This makes the bond much stronger than that of adhesive optical bonding.

One of the necessities for optical contact bonding is that the components have the highest surface quality enabled by excellent fabrication capabilities. We can not only fabricate the components here with high surface quality, but we can also perform adhesive and optical contact bonding. 

Anodic bonding is another type of optical contact bonding that does not require an adhesive. However, in addition to liquid-based, anodic bonding is performed using hermetic sealing. This process is performed by driving oxygen into the surface using an electric field. The result is silicon dioxide, which fuses the components. 

Anodic bonding requires the highest level of surface quality (such as a 10-5), and we can also create components suitable for anodic bonding. Anodic bonding is also known as field-assisted bonding or electrostatic sealing.

What Are the Advantages and Disadvantages of Optical Contact Bonding?

There are both advantages and disadvantages to optical contact bonding. Some of the advantages include:

  • Parts are fused as one 
  • There can be no adhesive damage, such as in adhesive contact bonding 
  • Less heat sensitive when compared to adhesive contact bonding 

There are some disadvantages, or rather things to know, about optical contact bonding:

  • Optical contact bonding requires complete precision 
  • It is more time- and labor-consuming 
  • Someone must be specially trained to perform optical contact bonding 

Generally speaking, optical contact bonding is an excellent fit for those who need precision components fused without adhesive. 

IRD Specs:

Max size Contact bonding 1.5″ / 38 mm

Min size 0.25″ / 6 mm

Roughness < 5 [Angstrom symbol] Ra

For more information or assistance with your glass or optical bonding needs, contact IRD Glass today.