The diminutiveness of the parts and the request for forceless measurement favor non-contact or low-force methods.
The assembly and alignment of electro optical components require the precise measurement of distances with a resolution and precision in the sub micrometer range.
The standard method is the camera system itself which is basically implemented in every nanosystec workstation. Machine vision algorithms including autofocus determine distances and orientation of the parts for gripping and prealignment. A calibrated motorized zoom allows for working in different fields of magnification.
Confocal sensors deliver results with a precision of a fraction of a micrometer. They are fast, compact and have a small measurement spot. This is of advantage if the object to be measured has fine structures and features.
If the objects can accept a small force, tactile sensors generate fast and precise results. They fit in almost every setup. Alternatively, strain gage assemblies determine the contact surface between the parts.