An optical lens is usually composed of a group of several lens elements. So how are the lens elements connected together? This issue will introduce the bonding process of optical lenses and understand its role in the manufacturing process of lenses.
Definition of the bonding process
The bonding process of optical lenses refers to the process of bonding two or more lenses or plane mirrors with matching optical surfaces using optical adhesive or light glue, according to certain technical requirements, to form optical components.
Requirements for bonding
In actual production, there are two aspects of requirements for the bonding of optical lenses:
First, to ensure the center error and angle error, for lenses, to ensure the center error of the lens; second, to ensure that the bonding surface achieves "zero defects" in bonding, that is, to ensure that the polished surface of the bonding does not lower the requirements for surface defects due to bonding, and does not affect the shape of the non-bonded surface due to bonding.
There are two methods for bonding optical lenses, namely the adhesive method and the light glue method. The adhesive method uses optical-grade transparent glue to bond several optical lenses into complex optical components. The light glue method relies on the molecular attraction between the polished surfaces of the parts to combine several lenses into a complex optical lens group.
What is the role of bonding in optical lenses?
1. Improve image quality
To ensure that optoelectronic instruments have good imaging quality and imaging requirements, for example, the bonding of positive and negative lenses can eliminate spherical aberration and chromatic aberration.
2. Reduce light energy loss and increase imaging brightness
Generally, the reflection loss at the air-glass interface of optical materials is 5%-6%, while the reflection loss at the optical glue-glass interface is only 0.1% or less. Therefore, bonding optical lenses together can reduce the number of air-glass interfaces, thereby reducing light energy loss and increasing imaging brightness.
3. Simplify the processing of optical lenses
Since bonding can compensate for slight differences in the curvature radius of the bonding surfaces, it can appropriately reduce the precision requirements of the bonding surfaces.
4. Protect the surface of optical parts
To avoid damaging the surface of optical scales, polarizers, or other component surfaces, protective glass is often bonded to the surface of the parts to protect these surfaces. For example, the outermost lens protection glass of a mobile phone lens is mainly to prevent damage to the lens from foreign objects.