Design and Application of Infrared Continuous Zoom Lens

The principle of infrared continuous zoom lens:

The principle of the infrared continuous zoom lens is to use two or more lens groups in the optical system to move linearly along the path given by the optical design, to change the combined focal length of the overall optical system, while keeping the position of the image plane unchanged, and in the The image is always clear during continuous zooming.

The lens group of the infrared continuous zoom system can be divided into several modules:

Front fixed lens group: The maximum light aperture is determined by the design parameters, and its function is to provide a fixed image for the optical system;

Zoom lens group: It is a group of lenses that move linearly to change the focal length of the optical system;

Compensation lens group: it is a group of lenses that do nonlinear linear motion, and compensates the shift of the overall image plane during the movement of the zoom group;

Rear fixed group: It is used to transform the image of the compensation group into a real image, and adjust the overall composite focal length value and the aperture diaphragm of the optical system.

Usually in the infrared zoom design, the micro-movement of the zoom lens group and the compensation lens group is fitted into two curves according to the data points, which are reflected in the cam of the structural design. The processing accuracy of the cam curve will directly affect the overall The imaging quality of the cam curve is high or low, so the higher the precision of the cam curve processing, the better, and the denser the data points given by the cam curve, the better.

In addition, the rear fixation group introduced above is not fixed in actual use. Due to the cumulative error of the lens and the lens holder, the imaging surface of the overall image will not be in an ideal position. Therefore, when correcting for the first time in actual use , needs a small amount of adjustment to make the imaging surface coincide with the FPA of the detector.