About Measurement of Surface Profiles

Commonly used seal rings are commonly used in industry. The edge of the seal ring is generally cylindrical or flat. However, the common feature is that the edges will have a certain thickness, and the dimensional measurement accuracy requirements are high, especially the military industry. The seal used.


Difficulties, problems

Distortion problem: The traditional imaging system will have distortion of 3% or more, especially in the edge region of the field of view, the image will be stretched and deformed to varying degrees, this distortion will cause the image edge contour distortion, affect the accuracy of the contour measurement, and due to Distortion is irregular, and later software correction is difficult. The problem is that the cross section of the seal ring is cylindrical. It is very difficult for the whole product to achieve a clear focus. The depth of field of the lens is small. No matter how the image is adjusted, it is false.

solution

Distortion problem: The distortion of the BT series of double telecentric lenses is controlled within 0.1%. All lenses are tested and corrected before shipment to ensure that the distortion rate of the image can be guaranteed even if the feature point is at the edge of the field of view. In a very small area.

Depth of field issue: The BT series of dual-telecentric lenses are designed using a special aperture principle. Normally the depth of field can be more than doubled (in comparison to a conventional imaging lens) when F# is guaranteed, greatly increasing the depth of focus within the field of view. .