Design of zemax photographic objective lens

1. Optical system CAD is an indispensable practical link in applied optics series courses. Together with applied optics (geometric optics, aberration theory and optical design), it constitutes a complete system from basic theory, applied theory to engineering design practice, which occupies a very important position in professional education and is also a characteristic course of photoelectric information engineering. Students have never been exposed to comprehensive design courses before studying this course, and they still lack understanding of the characteristics of engineering design. Judging from the composition of the student group, most of them are high school graduates admitted to universities, who are very unfamiliar with engineering problems and have very weak engineering consciousness. As a comprehensive design course, this course plays an irreplaceable role in cultivating students' engineering consciousness and engineering quality, making students gradually adapt to the change from learners accustomed to scientific theories and ideal assumptions to optical engineers and technicians, and cultivating students' ability to learn, develop and creatively solve engineering problems in the analysis and discussion of practical problems. In the past, the course adopted the mode that teachers assigned homework uniformly and students designed the course individually. Due to the limitation of objective conditions including software, students can only design relatively simple optical systems, such as simple telescopes and objective lenses. Teachers grade students by reading design reports. Due to the lack of competition among students, there are inevitably some cases of copying each other, which makes it difficult to achieve the ideal teaching effect and meet the actual work needs of students, and students are not interested. In view of this situation, the course teaching group believes that the basic goal of engineering teaching should be to integrate theory with practice and cultivate students' engineering quality and comprehensive innovation ability. According to the requirements of students' practical work after graduation, theoretical study, skill training, environmental adaptation and subjective personality are combined for training, which embodies the talent training goal of paying equal attention to KAQ (knowledge, ability and quality) put forward by the school. We believe that quality education and professional education are inseparable. As engineering teachers, we should devote ourselves to embodying quality education in professional education. As a comprehensive design course, this course is fully qualified to do better in cultivating students' subjective consciousness, innovative spirit, innovative ability, organizational ability and cooperative spirit. The second is the comprehensive reform of optical system CAD course. In recent years, the teaching team of this course, with the support of the leaders and teaching committee of the Optoelectronic Department and the Optoelectronic Information Experiment Center, has introduced the internationally used optical design software and made positive reform attempts in teaching methods and means, practice mode and so on. , and achieved good results, but also recognized by the majority of students. The specific practice is as follows. 1. The reform goal is to cultivate research ability and innovative thinking as the core, and to cultivate engineering quality as the main line, so that students can understand the actual needs in the future from the small environment of this course as much as possible, master the corresponding basic technology of this major, and take the all-round development of students as the reform goal. In the practice of curriculum design, it is of great significance to cultivate students' subjective consciousness, enhance students' subjective ability, shape students' subjective personality and exercise students' innovative ability, organizational ability and cooperative spirit. In particular, the establishment and improvement of student-centered self-evaluation and competition mechanism have enabled students not only to complete one of their own designs, but also to see the design achievements of other research groups in their defense, and to have a more objective understanding of their own advantages and disadvantages. The achievements of team members are related to his contribution to the research group, which also makes each student more active. Here, the final score is not the most important, the key is that every student has the opportunity to see himself with the third eye. 2. The reform of teaching content is based on engineering practice, so that each research group composed of students can complete personalized design. The teachers of this course have many years of practical scientific research experience, and there are several vertical and horizontal scientific research projects every year, which constitute a rich source of students' design projects. Of course, it is not appropriate for most design projects to be directly used as students' design topics. Teachers select some typical optical systems as students' design topics. It is difficult for students to design successfully through their efforts if the design topics are suitable for the design workload corresponding to the credits of this course. For some specific requirements of the topic, the teacher only put forward the minimum standards. For example, the aperture of the photographic objective of a digital camera is not less than1:2.8; The number of lenses, we only require no more than 6. Because the top is not capped, it gives students a lot of room to play and compare, and also avoids the same structural model. The course group has classified and integrated the previous design topics, added new design topics according to the development of the optical industry, and worked out detailed technical requirements that meet the actual needs, which can be used by several students without repetition. Originally, the course only had the task of optical design, but now the task of writing optical aberration calculation program is added. The purpose is to let students know how the basic part of modern optical design software is realized; Through the process of initial light setting, we can understand the role of diaphragm and entrance pupil in light calculation. Through the calculation of actual aberrations, we can have a deeper understanding of various aberrations and consolidate the weak links of students in the course of applied optics. Promote students to link the programming content they have learned with solving practical optical problems; Software quality is easier to judge and compare, and it is easier for students to find references when grading each other. The optical design part pays more attention to the training of the whole process of a design. From the initial structure to the drawings of optical parts, strict requirements are put forward for factors related to production and processing, such as process requirements and drawing standards. If you can't meet these requirements, even if you design it well, you can't participate in the defense. After the design, a design report should be completed, summarizing the whole design process, giving a complete evaluation of the design results and writing out the design experience. 3. Introducing scientific research mode into the reform of teaching methods and constantly improving the whole process of curriculum design is the focus of this curriculum reform. First, students are required to form a research group, usually a group of three students. If there are more than three students, the design task is more difficult, and the project leader should be selected. Finally, the results of the whole group should be given to the group leader, and then the group leader will distribute them to each member. The role of team leaders in design activities will be strengthened, which can train their organization and coordination skills. Practice in groups can cultivate students' team spirit and sense of cooperation, and form a good atmosphere of intra-group cooperation and inter-group competition. In addition, it can also improve the difficulty of task design, make the task closer to reality, and students will have a strong sense of accomplishment after completing the task. Teachers and research groups should sign a task book drawn up in full accordance with the development contract of scientific research projects. The task book defines the specific requirements and time nodes of each design task, and also defines the scoring standards and methods, and even the rights and obligations, intellectual property rights and confidentiality requirements are all available. Teachers ask students to read the relevant contents carefully before signing the task book, and be as cautious as signing a contract, so that students can establish risk awareness, responsibility awareness and credit awareness in curriculum research activities. At the same time, the task book also guarantees the time schedule and design quality of curriculum design from the rules. According to the task book, the teacher's responsibility in this process is to teach students the corresponding design methods, let students learn to use design software and help them complete the corresponding design tasks. In the whole course design, teachers only give lectures for 8 hours, accounting for 1/5 of the total class hours. However, the task of teacher counseling is very heavy. In addition to tutoring in the prescribed computer time, teachers usually use online discussion boards to answer various questions raised by students. After receiving the task book, the research group should conduct research and analysis, decompose the task and assign it to each member. For example, in software design, one classmate does the algorithm, one classmate does the interface, one classmate does the graphic output, and finally a very decent computing software can be made; Optical design requires each group of students to give a design result that can meet the requirements, and finally find the best one among several results as the final result of the whole group. This is to let every student really participate in the design, get a complete design training, and see more structural forms through the comparison of various schemes, so that students can learn from each other and get better results. When the design reaches the required imaging quality, it is also necessary to check whether the system meets the requirements of processing and assembly technology. The design also requires drawing system drawings and parts drawings that can be provided to structural design and optical workshops as much as possible. Whether the drawings are standardized is also an important basis for judging. After checking the completion of all tasks and the design results and materials, teachers can make a design defense. If they find that they don't meet the requirements of the task book, they will continue to work until they pass. As can be seen from the above process, the course is completely set according to the formal research process of a scientific research project. 4. Teaching Conditions and Means With the support of Optoelectronic Department and Optoelectronic Information Experimental Center, we introduced Zemax, an optical design software widely used internationally and also widely used by domestic enterprises and research institutes, to design the course, which improved the quality and difficulty of students' design, enabled students to better link this course with the actual needs of society from the fundamental idea of optical transmission, and enabled them to understand the basic situation and usage of optical design software, and get further research and development topics in the future. According to the requirements of curriculum design, we have added relevant optical process requirements and optical drawing in the new textbook. In order to provide students with rich conditions for self-study and research, it is an essential task to establish and improve a distinctive course website. At present, the course group has established a website with relatively complete resources. (/k/548/).5. The reform of assessment methods and the acceptance of students are also important signs to test the success of this project. Usually, after a scientific research project is completed, the entrusting party will organize a review meeting. Therefore, the assessment method of this course is also the form of defense. We use the method of defense review committee composed of representatives of each research group to review, and divide the design task into four parts: program design, optical design, drawings and reports. When one group has a few minutes to ask questions after presenting the design report, the judges of other groups will grade the four parts on the spot, and the average score after removing the highest score and the lowest score is the defense score of the group. After the score comes out, set aside a few minutes to defend the team, and the referee can decide whether to change the score according to the situation. If all replies are scored together, there are too many groups and time is not allowed. We will reply in small classes. Considering the balance of scores in each class, the top students in each class will be given a general reply. The scoring principle of defense is fairness, justice and openness, and corresponding rules are formulated at the technical level. In this respect, teachers have also experienced a change of ideas. We have always said that students are the main body. How to embody this subjective role and whether to believe in students' subjective ability are key issues. Often on specific issues, teachers think that students can't bear such main responsibility, and students can't get rid of the idea of relying on teachers. Teachers still lack confidence in themselves as judges. After several sessions of practice, we believe that defensive grading can be wonderful as long as a reasonable competition mechanism is introduced and the grading method is reasonably refined on the basis of listening to the opinions and suggestions of the majority of students. Three. Conclusion Through several years of practical exploration, the reform of this course has achieved gratifying results. First of all, it has been widely supported, fully affirmed and participated by students. They actively offered suggestions and came up with many good ideas. Many of the above practices were implemented after listening to their opinions and suggestions. Their speeches are often passionate and colorful, and their scores are basically objective, fair and reasonable. It is because of the support and participation of students that our curriculum reform has achieved such success. From their design summary and experience, it is reflected that this teaching method allows them to really invest in the course. Although the course only has 1.5 credits, they often work all night, and getting credits is no longer the main purpose. Most students believe that through the study and practice of this course, the efforts made, the things learned and the things experienced are far from being measured by credits and grades. After graduation, many students also told us that the form and content of such courses are very good, and they have learned a lot that ordinary classes can't. It is also very helpful to consolidate the knowledge learned and understand the application of this knowledge. The new practice teaching also makes the relationship between teachers and students more harmonious, deepens the feelings between teachers and students, and enhances mutual trust. Although the relationship between teachers and students in the task book is like the relationship between Party A and Party B, in practice, the two sides are more like teammates of the same side, supporting and encouraging each other to accomplish common tasks. Although the reform has achieved initial results, we also know that the reform of engineering courses, including such practical courses, still has a long way to go. Only by continuous efforts and bold exploration can we meet the needs of social development and scientific and technological progress for talent training.