Confocal microscopy (also referred to as confocal imaging) follows a two-step optical workflow:

First, the light source pinhole forms an image at the focal point on the sample surface;

Second, this focal point is then imaged onto the detection pinhole.

The diagram below illustrates the optical principle of a confocal

microscope:1 Light Source；2 Source Pinhole；3 Beam Splitter (Half-mirror)；4 Chromatic Aberration Objective Lens；5 Specimen / Workpiece；6 Detection Pinhole；7 Photodetector；8 Vertical Displacement Stage；a Light beam focused on the workpiece;b Out-of-focus light beam。

Light passes through the objective lens twice along opposite propagation directions;

All optical components adopt a coaxial layout.

The chromatic aberration objective lens moves vertically along the optical axis. The detected signal peaks when the light beam is precisely focused on the workpiece surface. Accordingly, the surface height of the specimen can be quantified by analyzing signal data from the photodetector.

Principle of Axial Chromatic Dispersion

Component Legend:1 Point Light Source，2 Dispersive Objective Lens；a Focal plane for the shortest wavelength，b Focal plane for the longest wavelength

；c Axial Chromatic Dispersion。

Applications of Confocal Micro Measuring Instruments