With the laser scan type, the measurement point is only one dimensional. It is impossible to measure multiple points simultaneously or to correct target inclination.
2D measurement captures all of the target information at once. The measurement is based on the 2D silhouette image projected on the CMOS. This allows measurement at desired points or measurement with position correction, which is possible only by using 2D images.
The path of the laser scan varies with every sample due to the surface accuracy of the polygon mirror. The laser scan type is also affected by inconsistent motor rotation which increases over time. The longer the instrument is used, the greater the inconsistency of the laser scan path becomes.
The 2D method allows measurement of the entire range in one instant. Since no scanning laser is used, a specified point can be measured exactly.
The driving mechanism decreases durability and requires maintenance. There is also a concern about laser deterioration due to electrical noise.
[ No motorised mechanism ]
A system with no moving parts provides higher durability. This eliminates the problem of motor durability which has been a disadvantage of laser scan type micrometers.
[ Ultra long life LED ]
The GaN (Gallium Nitride) LED used as a light source has achieved high reliability without being affected by light source deterioration due to electrical noise.
A semiconductor laser beam is applied onto a polygon mirror which is rotated by a motor to scan the measuring range. The time in which the laser beam is interrupted by the target is measured to obtain the dimension of the target.