Confocal microscopy principle
 

The advantages
 One major advantage of the confocal microscopy principle is the high vertical and lateral resolution.
An increase of nearly 20% lateral diffraction limited resolution compared to conventional microscopy is achieved through the physical pinhole filtering.
A second advantage is the ability to measure steep edges, complex structures or transparent coatings.

  10x 20x 50x 100x
Resolution z [nm] 50 30/20* 20/10* 20/5*
Field size [µm] 1600x1510 800x755 320x302 160x151
Max. stitching size
[mm x mm]		 121 36 5,7 1,4
Working distance [mm] 10,1 3,1/12** 0,66/10,6** 0,31/3,4**
Numerical aperture 0,30 0,46/0,40** 0,80/0,50** 0,95/0,80**

* Piezo, ** Long distance

Determination of height data
The height data of a point can be determined precisely by using fast algorithms for evaluating the intensity distribution
Schematic diagram of the confocal microscope
Combined with CCD image processing, the rotating Nipkow disc affects the xy-scan of the object field in real-time video. An additional z-scan is used for the evaluation of highly precise height data.
Schematic diagram of the confocal microscope

3D confocal microscopy

The principle
In white light confocal microscopy light emitted from a point light source is imaged into the object focal plane of the microscope objective. The reflected light is detected by a photo diode behind a pinhole. This arrangement leads to a part suppression of light from the defocused planes. The area scanning technology replaces the detector pinhole with a rotating disc in the intermediate image plane. This Nipkow disc consists of a spiral-shaped multiple pinhole mask.