STEMMER IMAGING

Advantages of telecentric lenses

With standard lenses an object appears to be smaller or bigger when it is closer or further away from the lens. Unlike common optics, telecentric lenses only accept incoming ray bundles that are parallel to the optical axis; therefore the object size remains unchanged. This is essential when you must measure objects that cannot be precisely positioned (e.g. on a conveyor belt).

Moreover, telecentric lenses eliminate any perspective error and are therefore perfect when thick objects must be measured.

Telecentric lenses also outperform standard lenses when it comes to distortion: An image is distorted when straight lines in the object space appear as curved lines in the image space. Distortion is measured as a percent deviation. Opto Engineering telecentric lenses feature incredibly low distortion, typically under 0.05 % and deliver extremely accurate geometrical information.

Special features of bi-telecentric

Bi-telecentric lenses are also telecentric on the detector side. This additionally guarantees:

• Increased Field Depth
• Even CCD illumination
• Constant magnification even when the CCD is not perfectly positioned

Bi-telecentric lenses are able to deliver incredibly accurate measurement on many different precision parts.

Opto Engineering bi-telecentric lenses are specifically designed for real industrial applications. The lenses have a fixed design with no adjustable focus or aperture mechanisms to withstand vibrations and ensure accurate and consistent performance.

Characteristics of the Opto Engineering TC 4M and TC 2M lenses

The Opto Engineering TC 4M and TC 2M lenses are bi-telecentric lenses designed for detectors larger than 2/3”. TC 4M lenses cover up to 21.5 mm detector diagonal and are therefore suitable for 1.2” imagers and 2048 x 2048 pixels (4MP) KAI detectors. TC 2M lenses cover up to 1” (16 mm diagonal) detectors.

Models

• Object field of view from 3.0 x 2.2 mm to 247.9 x 186.3 mm
• Typical distortion between <0.02% and <0.08%
• Field depth up to 259 mm
• Diameter from 28 mm to 322 mm

Markets and applications (examples)

• Automotive
• Electronics
• Pharmaceutical
• Beverage