In recent years, AR technology has shown broad application prospects in the field of education. Education based on AR technology emphasizes the interaction between learners and the environment, and establishes the link between knowledge and response, which is exactly in line with the behaviorist "stimulus-response" view of learning. AR provides rich tools for constructing virtual learning environments and gives more choices of autonomous control, which is exactly in line with the view of "learning is an experience of real situation" in constructivism learning theory and Piaget's assumption and practice of "moving the laboratory to the classroom".

The application of AR technology in the field of education has the following characteristics, just to meet the needs of children's education, and AR combined with other technologies, can also play a greater potential in the field of children's education. The main features include :(1) intuitive and vivid display of abstract learning content; (2) To provide rich learning situations in a ubiquitous environment; (3) Improve learners' intuition, sense of presence and concentration; (4) Natural and diverse interaction modes; (5) Support ubiquitous learning by combining formal and informal learning.

1. Application of AR technology in formal education

The interactive and exploratory characteristics of AR make it suitable for early childhood education, because children at this stage like to explore and need a high degree of freedom and movement.

In the stage of preschool education, children's intellectual development level is low, understanding ability is limited, and there are some differences in the way of accepting new things. Therefore, THE AR application at this stage is mostly to establish the transfer and link of thinking between simple and abstract learning content and the familiar and intuitive related things of children. For example, AR technology is used to strengthen children's understanding of mathematics, numbers and counting rules, and physical enlightenment teaching is carried out for children aged 4 to 6 years through AR construction situation. AR can also be used to help preschoolers establish the connection between words, physical models and pronunciation.

In the primary education stage, children's intelligence and understanding ability develop further, and their ability to accept new things is also enhanced. Therefore, more complex and abstract learning content will be introduced. The application of AR technology at this stage can arouse children's interest in learning and promote their understanding of abstract and complex content. The introduction of AR requires teachers to learn new skills and accept the changes in the educator's role that will result from the adoption of these AR tools. Several studies have shown that implementing AR in schools, including some elementary schools, improves student academic performance. Some scholars try to combine the somatosensory natural interaction technology with AR technology, so that teenagers can learn physics knowledge in sports. For example, Barreira developed an AR app for teaching animal words in different languages at the elementary school level. Different combinations of animals and flags result in animal words in different languages, and the correct pair of words and animals presents a 3D model of the animal. In addition, the gamification of AR learning process can mobilize the enthusiasm of students to learn mathematics.

At the early stage of middle school, AR technology began to be used to explain abstract concepts, cultivate scientific thinking, and build virtual and real learning environments. In mathematics education, AR application pays more attention to the cultivation of mathematical thinking and specific learning effects, and may even change the learning paradigm of mathematics in the future. In the field of chemistry, AR is mainly used as a means to display the contents that cannot be directly observed, such as molecular and atomic structures.

Cai has designed a virtual-real fusion experiment to teach the structure of chemical substances in junior high school. In the experiment, virtual molecules and atoms can be operated, combined and created in a natural interactive way. The Catholic University of Chile has designed and developed an example classroom AR game to teach the basic concepts of electrostatics. CAI Su designed and implemented AR concept demonstration book, which is used to show basic experiments such as simple pendulum in middle school physics, giving learners intuitive image feeling. Santos uses AR and other technologies in vocabulary teaching, scanning real scenes to obtain relevant learning vocabulary, so that learners can pay more attention and be more satisfied with learning. Chiang in inquiry learning in biology teaching in middle schools link the introduction of AR technology, will be sent to students from different areas to explore, based on the geographic location of the AR is applied to study biological knowledge and upload, for other students to arrive at the place of share the contents of the view, so as to enrich learning experience and give full play to the role of various kinds of new technology. Wang developed a mobile AR survey tool to support field data collection and map viewing. Hsiao has developed an AR weather system to aid geography learning, which presents different content in different teaching sessions, such as the classroom, home and museum.

2. Application of AR technology in the field of informal education

AR books is the application of AR technology in books, so that static pictures and pictures "live" up. Usually, through the camera on the mobile phone or tablet to scan the pictures on the specified page number of the AR book, the plane image in the book can be seen through the screen into A 3D three-dimensional model, click the screen can also be interactive, the visual picture is expanded to audio-visual multi-dimensional experience.

Many of the developers involved have done a lot of productive research. Magic Book is the first set of AR children's books. HMD can be used to watch the AR animation content superimposed on each unit of the Book. Nd has developed interactive books that allow readers to tell their own stories and create storylines, as well as AR coloring books that feed back to 3D models with line drawings. Ali has developed My Vision AIR, a mobile interactive book that includes pictures, models and videos to make reading fun. Cheng has created an AR pop-up book that can scan story pictures and present real scenes of models. In science and technology museum, museum application, AR technology has been very common. AR technology can not only help to present the physical objects that cannot be displayed or some of them are difficult to be displayed in the fixed point exhibition to enrich the content and form of the exhibition, but also help to integrate different forms of resources such as introduction, knowledge links, models and games in the guided tour, bringing visitors a comprehensive and vivid experience. Klopfer has proposed a MAR education system in collaboration with museums, where children use pocket PCS and walkie-talkies to interview virtual characters and operate virtual instruments. Chang has developed a system that combines art appreciation with MAR technology to improve the learning of art museum visitors during their visit. The system can locate and overwrite the information on the current picture, and also provides the function of zooming in the virtual picture. Freitas has developed an AR transportation education system for younger students, where virtual 3D models such as cars and airplanes are overlaid on live video to show concepts of transportation and animation.

For students with special needs, especially those with attention impairments and memory impairments, Lin has explored a new way to apply AR to educational activities for children with disabilities, providing step-by-step guidance. Teachers can also design multi-level teaching strategies to help children with special needs learn independently.

3. Application of AR technology in educational games

Educational games are games developed specifically for specific Educational purposes, emphasizing both education and entertainment. AR educational games can freely construct virtual game scenes or add experience layers to support situational learning.

"Environmental Detective" is an educational game developed by the Schler Teacher Education Program at the Massachusetts Institute of Technology. It uses MAR technology to create learning situations. The game combines virtual digital information with real world experience, adds an experience layer, sets up virtual character visit, simulation environment measurement and simulation data analysis and other links, in order to achieve the educational purpose of scientific exploration. "Contact Aliens" is an AR game developed by Radford University to improve the scientific literacy of middle and high school students. The Technical University of Valencia developed an interesting AR educational game -- "Understanding endangered Animals". After a controlled experiment on 46 children, it was believed that AR educational games were more popular among children and could produce better teaching effects compared with other teaching methods. The University of Sao Paulo research team has developed an AR music education game called "Gen Virtual" to improve the musical performance skills of people with learning disabilities, as well as improve creativity, attention and motor coordination.

AR technology application in education games, it can obviously improve school-age adolescents perception of things depth and the study effect, especially in education for special children opened up new and have good prospects of possible paths, really achieve the education without missing a person, let all teenagers have the chance to enjoy the high quality of education possible.

4. Influence of AR technology on children's education

In view of the good application prospect of AR technology in the field of education, relevant scholars have conducted in-depth and systematic evaluation of the impact of AR technology in children's education, and have drawn many important conclusions.

Cascales has conducted a detailed study of the effects of using AR as a learning tool in preschoolers. The results show that AR resources may be suitable for multiple learning levels. Using AR improves children's reading and writing skills, so they can get better grades, which is important for preschool education. Yilmaz revealed the views of teachers and children on AR educational magic toys, identified children's behavioral patterns and their cognitive achievements, as well as their relationship when playing AR educational magic toys, and clearly pointed out that AR educational magic toys can be effectively used in early childhood education. Alhumaidan tried to involve primary school children in the design and evaluation process of an AR textbook that tells about collaborative learning experience, and then strengthened the research on collaborative learning experience in primary school education through the collaborative design of AR textbooks. Lee studied how AR technology can be used to enhance the learning experience in early childhood, while addressing parents' concerns about the health effects of their children's long-term use of electronic devices. Boonbrahm created three AR experiments focusing on writing, reading and dialogue respectively, and the results show that AR plays a good motivational role in children's English learning process.

Koutromanos reviewed a large number of relevant studies on the application of AR in formal and non-formal education environments, and proved that the application of AR technology in education has a cumulative effect on the improvement of students' academic performance. After comparing the learning performance of students who use AR with those who do not, Radu believes that MAR application can significantly improve learners' performance, enhance their cognitive depth and memory effect, and direct students' attention to learn-related content, interaction, collaboration and learning motivation. However, there are inevitably some negative effects, such as reducing the attention of learners to mistakes and so on.

To sum up, the application of AR technology has produced many positive effects on children's education. However, it is undeniable that the application of this technology has some negative concerns, such as reducing children's attention to mistakes and affecting children's health, which should be solved gradually in the future AR application technology research.

5, conclusion

AR is likely to become the next major computing platform along with VR, where AR will enter people's lives faster than VR. The AR/VR market is expected to double or more in global revenue over the next four years, according to market research firm IDC's recent "Global Semi-annual Augmented reality and Virtual Reality Value Guide".

In addition, AR technology has been listed by many countries as the key development of educational application technology in the next few years. However, how to use AR technology to improve the learning environment, how the virtual learning and teaching environment built by AR can more effectively support learning and teaching, and how to redefine the concept of education in the AR teaching environment are still major issues to be solved. AR is an extension of VR technology. With the continuous progress in mobile devices, computer vision, mobile cloud computing, Internet access and cooperative network, AR has quickly entered people's lives. AR technology is a hot research topic for scholars at home and abroad, and the application of AR in children's education is the focus of many countries and organizations, which has a good application prospect.