Zoom lens with high zoom ratio design based on Gaussian bracket and particle swarm optimization

Design of an optical passive semi-athermalization zoom lens

Traditional zoom lenses cannot clearly image during the entire zoom process when the ambient temperature changes and needs to focus frequently at middle focal length positions. An innovative design method called the optical passive semi-athermalization (OPSA) design for zoom optical systems is proposed which, based on the difference in the focusing sensitivity of the focusing group at short and long focal length positions, seeks out sensitive groups that have a greater impact on the imaging quality at the short focal position. By changing the temperature characteristics of the temperature-sensitive lenses in these groups, an OPSA zoom optical system can be realized, which exhibits a compact structure and excellent imaging quality. Under the ambient temperature of -40∘ C to +60∘ C, the OPSA zoom lens needs to refocus only once at the long focal length position, which can ensure an image clearly during the entire zoom process. Remarkably, this innovative method not only mitigates the frequent focusing challenges in traditional zoom lenses, but also contributes to the diminutive size.

Optimization method of the cam curve for a continuous zoom optical system

To make the driving force of a zoom cam cylinder stable and easy to control, the correlation between the cam curves of the zoom group and the compensation group is established effectively by reasonably selecting and arranging the coordinate system. Two optimization methods of cam curve are proposed. First, the original data are processed directly by the function of the target cam curve, and then the dynamic parameter such as the pressure angle is verified again to obtain the expected cam curve. This optimization method is simple and convenient, and a variety of optimization results can be constructed. Second, a physical model of multiple cam curves and the driving force with only one variable is constructed. The step search optimization method is used to process the original data point by point, and the best cam curve matching the model is obtained. Through dynamic simulation, it is determined that the cam curves designed by this optimization method can drive the zoom group and compensation group to complete the whole continuous zoom movement with a stable torque.

Deep Learning Enables Optofluidic Zoom System with Large Zoom Ratio and High Imaging Resolution

Due to the relatively low optical power of a liquid lens, it is usually difficult to achieve a large zoom ratio and a high-resolution image simultaneously in an optofluidic zoom imaging system. We propose an electronically controlled optofluidic zoom imaging system combined with deep learning, which achieves a large continuous zoom change and a high-resolution image. The zoom system consists of an optofluidic zoom objective and an image-processing module. The proposed zoom system can achieve a large tunable focal length range from 4.0 mm to 31.3 mm. In the focal length range of 9.4 mm to 18.8 mm, the system can dynamically correct the aberrations by six electrowetting liquid lenses to ensure the image quality. In the focal length range of 4.0-9.4 mm and 18.8-31.3 mm, the optical power of a liquid lens is mainly used to enlarge the zoom ratio, and deep learning enables the proposed zoom system with improved image quality. The zoom ratio of the system reaches 7.8×, and the maximum field of view of the system can reach ~29°. The proposed zoom system has potential applications in camera, telescope and so on.

Double-sided telecentric zoom optical system using adaptive liquid lenses

In this paper, the adaptive liquid (AL) lenses are introduced into the double-sided telecentric zoom system, which could greatly decrease the mechanical motion group compared with the traditional zoom system, and only one movable aperture stop (STO) is retained. Firstly, this paper derived the Gaussian brackets used in this system, and we found the appropriate screening method to get the suitable initial structure parameters from the solution space. Then we used the lens module design method to create the initial system. Finally, we used CODEV to further optimize the system, and we got an excellent design result, which controlled the telecentricity of both sides within 0.1°, the distortion was controlled within 0.5%, and the MTF of each zoom configuration above 0.3. This optical system has high application potential and value in the field of precision machine vision. The design method proposed in this article can effectively solve the problem that the zoom system using adaptive liquid lenses lacks the initial structure.

Optimal focal length search and design of a compact zoom lens based on a telecentric intermediate image

The design of a compact zoom lens requires a designer's most abundant and professional skills and experience, which increases the difficulty of zoom lens miniaturization. In this paper, an automatic optimal focal length search method for a catadioptric zoom lens is proposed. After 7 h of searching for the initial structure and further optimization, a 3× compact zoom lens based on a telecentric intermediate image is obtained, which is applicable for 1/4 inch (6.35 mm) CMOS, with a focal length range of -4.8∼-14mm and a F-number range of 2.7-8.0. The depth and total length are within 6 mm and 30 mm, separately. The proposed method helps to reduce researchers' difficulty in designing compact zoom lenses and can provide some reference for the development of the mobile zoom lens industry.

Automated design of a slim catadioptric system combining freeform surface and zoom lens

The development of electronic industry demands miniaturization for zoom lens. Freeform surfaces and catadioptric lens system play important roles in the compactness of optical design. However, the initial structure of the catadioptric system is relatively rare and repeated optimizing in first-order lens design requires advanced knowledge and experiences. That brings challenges for establishing an initial structure for the freeform catadioptric zoom system, which is essential for optical designers. In this work, an automatic design method for the initial structure of a catadioptric system with freeform surface and zoom lens is proposed. As long as the focal length range and total length are determined, the initial structure of the catadioptric zoom lens with arbitrary zoom ratio in a certain range can be obtained for further analysis and optimization. The rapid design method reduces the dependence on experience for catadioptric system design, saves considerable time and can help to ease the difficulty in finding the initial structure of slim zoom lens.