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Measurement Examples
Confocal Laser Scanning Microscopy (CLSM) Principle
Optical sectioning 3D imaging
- depth discrimination
Improved SNR (signal to noise ratio)
- out-of-focus blur rejection
Improved lateral resolution
- up to 1.4 fold
Light from an out-of-focus point is focused on a plane other than the pinhole aperture.

Thus only small portion of this light is detected. This makes the information from out-of-focus points rejected. By doing this, very clear image of thick specimen is achieved. For conventional optical microscopy, clear image of thick object can only be achieved by physically sectioning the object.

For confocal microscopy, this can be done without the physical sectioning.

Due to this optical sectioning ability, confocal can measure clear image of thick specimen and eventually three-dimensional structure of specimen.
Confocal Laser Scanning Microscopy (CLSM) 2D Scan Principle
Point-by-point imaging : 2D image acquisition
Most of confocal microscopy achieves information for only one point of the specimen at a time.

To achieve two-dimensional image of specimen, either the specimen or the focused spot should be moved. In most cases, the spot is moved due to the image acquisition speed.
Confocal Laser Scanning Microscopy (CLSM) 3D Scan Principle
Plane-by-plane imaging : 3D image acquisition
To acquire 3D information of the specimen, either the confocal optics or the specimen should be moved along the axial direction.

The movement of the specimen is not practical in many cases due to some reasons: the movement of the specimen can changes the morphology of the specimen especially in biological applications, and the inertia of the specimen is too large to move the specimen especially in industrial applications. Thus the objective lens is scanned along the axial directions. For fine positioning, the PZT actuator and the stepping motor are usually used. The stepping motor is usually used for coarse positioning due to its relatively long range and high positioning resolution.
Confocal Laser Scanning Microscopy (CLSM) 3D Profiler
Ideally, signal is detected only when the focus is on the surface
Confocal Laser Scanning Microscopy (CLSM) Image Comparison
Normal Microscope Image
2 dimensional Images of confocal microscope are more distinct than normal microscope's images
Confocal Microscope Image