MORITEX’s bi-telecentric lens was designed to offer leading performance even among our advanced MML series. Each bi-telecentric lens comes with its own actual MTF measurements.
*MTF stands for modulation transfer function (space frequency). This indicates decreased contrast in the number of black and white pattern bars per mm of image plane when black and white pattern bars with continuously changing intensity are formed by the lens. MTF is one way to evaluate a lens' capability to re-produce contrast. Moritex uses MTF to inspect for image formation capability and contrast simultaneously from the center to the edges of the image area.
Features
- Designed to position principal ray parallel to lens optical axis at both object side and image side by controlling viewing angle as "near-zero"
- Maintaining image side magnification regardless of how close/far the object is located, providing an ideal solution for dimension measurement
- Highly accurate measurement can be achieved even for the object position with angle or different height
- Incident angle to the sensor is constant generating less shading and resulting in an image with very uniform brightness
- Stable, repeatable measurement is possible in addition to reducing the effect of object position offset even if camera or sensor installation is not securely fixed along the optical axis
Telecentric lenses view objects differently

Telecentric effect
Connector component

When viewing a connector from above, a macro lens (photograph 1) will display the center part of the image free of distortion, but parts of both edges cannot be seen due to distortion. Also, a large discrepancy occurs in how the center part and edges of the image is seen, which could result in failure to detect defects or the inability to measure dimensions correctly.
In contrast, a telecentric lens (photograph 2) enables precise measurement of dimensions because there is no distortion in either the center part or edges of the image.
Impurities

Images taken with an ordinary optical lens, such as a macro lens, deliver a good quality center part of the image, but the bottom surface of the image edges is not visible due to angle of view. Therefore, in some cases inspections for liquid or impurities cannot be carried out.
The view angle of a telecentric lens is always near 0°, so the bottom surface even of the edges is correctly re-produced, making it possible to carry out accurate inspections for liquid or impurities.