Telecentric lenses are defined as those whose image magnification does not change with the change of object distance (or does not change with the change of depth of field) within a certain object distance range. Traditional lenses have a field of view angle. As the object distance increases, the magnification will also increase. In detection applications, the field of view angle will cause aberration (angle error), thereby reducing the detection accuracy. This feature is very important for detection applications where objects are not on the same object plane. Telecentric lenses have a larger depth of field and smaller measurement distortion than traditional non-telecentric lenses, so bi-telecentric lenses have unique advantages in size measurement, defect detection, irregular object detection, etc. LBTEK bi-telecentric lenses have ultra-high telecentricity, high resolution, high depth of field, low distortion, etc., and can effectively balance depth of field and resolution with adjustable aperture. Using C-Mount optical interface, it can be directly connected to the camera without the use of other adapter components, and can support industrial cameras with a maximum CMOS size of 1.1''. It can be widely used in precision parts measurement, non-contact optical measurement, glass product detection, electronics and medicine.