OptiCentric® Principle Setup
Optical Measuring Head
The optical measuring head of the instrument is designed to view and quantify the
size of the centering error in single and multiple optical components. It is also the basic
unit used for alignment of single elements before cementing or mounting in cells.
This is usually an autocollimator equipped with additional head lenses which is focussed in
the image plane of the sample (transmission method) or in the centre of curvature of the
lens surface under test (reflection method).
Stands with Travel Mechanism or Motorized Stages
The optical measuring head is mounted on a stand having capabilities to move up and
down in order to adapt to a certain range of radii of curvature (for Reflection Mode) or of
focal length (for Transmission Mode).
Sample Holder
Depending on applications OptiCentric® METRO provides a large variety of sample
holders: self-centering holders, vacuum retention devices, hydrostatic chucks, three jaws
chucks, etc.
Lens Rotation Devices
Since the viewing and the measurement of the centering errors are only possible when
the lens is rotated (except for extremely expensive errorless focusing devices), the availability
of a lens holding and rotary device is crucial for completing a centering measurement.
The accuracy of the centering measurement and of the alignment/mounting of lenses is
determined by the two basic components of a centering/mounting equipment:
- Optical measuring head
- Lens Rotation Device
Many optics manufacturers underestimate the importance of the Lens Rotation devices
in ensuring the required accuracy. Since the use of accurate CCD-cameras and complex
image processing software provides a high accuracy of optical measuring heads, the
largest error source in lens centring and mounting is in many cases the Lens Rotation
Device. Many of the Lens Rotation Devices used in the optical manufacturing do not provide
a reference rotation axis which is enough accurate and stable.
TRIOPTICS invested a large amount of work in designing a complete range of accurate devices
for lens rotation:
- Motorized Vacuum-Lens Rotation Device
- Ultra-Precision Air Bearing Rotary Table
- Mechanical and Hydrostatic Lens Holders
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