Compared with other optical lens, the telecentric optical lens is superior thanks to its no optical parallax, small distortion, high resolution and high acutance… The same with other fixed rate lens, the telecentric lens is given focusing position at the beginning of design, i.e. working distance, which is an important factor of lens and nonadjustable.
The working distance of telecentric lens, which has no specific industry standard available, has to be defined by the corresponding lens manufacturers based on the specific models. As a demerit, the application scenarios of customer are restricted and it is difficult to adjust the installation space and shot environment. There’s no big problem of feature detection to the fixed plane; however, if object features detected are not flat or they are step surface or curve, or the feature of object to be detected per time may have uncertain displacement deviation for lens, a lot of problems will be caused. According to the previous strategies, the lens should have sufficient depth of field as required by customer in order to deal with the case.
It is known that the depth-of-field image is a helpless action, for depth of field is a dynamic variable and images in depth of field may have different resolutions in different working distances. The uncertain variable always leads to the instability of algorithm testing. As lens has limited depth of field, the testing beyond depth of field has to be tested by the one and only method: setting several more image collection positions in different areas and working distances. However, this solution has the demerit of high cost, low efficiency and poor stability.
As we know, the deformation of liquid lens is controlled via voltage and it has millisecond-class change, which means, the change of liquid lens is controllable and efficient. By combining the advantageous performance of liquid lens and optical path of telecentric lens, we have developed the optical system with millisecond-class and stable variation of working distance. The lens developed based on this optical system inherits the advantages of telecentric lens and also solves the bottleneck of single working distance of telecentric lens.
For camera the lens of which is fixed, the focusing position of lens can be changed within certain working distance by switching the driving voltage of liquid glass. We can see in the picture above focusing position is decreased to the top of camera from the bottom QR code icon. The dynamic videos of this test are available on the website. For any interests in optical parameters of this liquid telecentric lens, please contact the Company directly. We will keep doing other follow-up tests of other liquid lens. If you are interested in the products, please do follow us.