Should Lenses Be Actively Aligned?

In the context of modern manufacturing environments where precision down to the micron is crucial, the use of high-resolution lenses in machine vision has become increasingly common. These lenses offer greater magnification, higher resolution, and sometimes even auto-focus capabilities, catering to diverse applications. However, achieving optimal performance from these lenses necessitates careful alignment during production.

A basic lens comprises components such as a housing, spacers, and multiple glass elements. To ensure optimal performance, these elements must be aligned along their optical axis and be parallel. Any dimensional variations during manufacturing can lead to improper fit and misalignment, affecting the lens’s functionality.

In the production of low-quality, mass-produced lenses, Passive Alignment is often used, relying on components fitting together based on their design specifications. However, this method lacks the ability to make adjustments during assembly. Even minor dimensional discrepancies can cause misalignment, resulting in focus issues or distortions.

On the other hand, Active Alignment offers a superior approach to lens assembly. This process allows adjustments to be made to the elements during assembly, ensuring precise alignment. Active Alignment is particularly crucial for lenses with numerous elements, each capable of impacting the lens’s performance.

There are various methods for Active Alignment, typically based on the lens’s actual dimensions rather than planned specifications. Techniques such as spinning the lens or using lasers to detect off-center elements are employed to achieve accurate alignment. Adhesive is then applied to secure the proper alignment after fine adjustments are made for each element.

Although Active Alignment can be time-consuming, especially for lenses with complex designs, it is essential for producing high-performance lenses. In applications like circuit board inspection or cell sample analysis, where detail visibility is critical, failure to achieve proper alignment can lead to significant consequences.