Capitalization of English letters in the back door of Gong and Song Dynasties is due to the design needs of human body stickers. When this kind of car leaves the factory, it usually carries a lot of body logos, which are usually printed with readable fonts and graphics to enhance the beauty and recognition of the car body. Generally speaking, capital letters usually express a more powerful and firm feeling, while lowercase letters are more likely to have a light and flexible atmosphere. For the public to explore songs, the mixed use of uppercase and lowercase letters can better express the design, positioning and connotation of the car. Of course, this is only for the visual effect, which has little effect on the performance and function of the car.