Confocal Point Focus Alignment Pattern (PF-C)
|Name & ID||Symbol||Typical Target Used||DOF and Sensitivity||Description|
|Confocal Point Focus (PF-C)||Reflective Tooling Ball||Fine interferometric alignment of dX, dY, dZ||Projects a focused spot to center of a reflective tooling ball.|
Confocal Point Foci (PF-C) can assess dX and dY alignment of a curved reference target (often a spherical tooling ball) by assessing tilt fringes in the pattern. dZ of the target can also be assessed in a PF-C by reading power fringes in the pattern.
- Fringes are not visible in PF-C pattern until the reference target is very close to alignment. It is recommended to include a coarse alignment aid (such as visual point focus PF-V) along with the PF-C pattern or move to an alignment pattern with greater dynamic range, such as LF and AF patterns.
- Diffraction limits the implementation of a PF-C pattern to < F/5.