With the increasing requirements for brightness, visual effects and energy consumption of automobile instrument panel lighting and display instruments, in view of the significant advantages of high-performance optical films in adjusting the optical path, it has been used to replace traditional plastic films for Car displays and dashboards have become possible. This paper introduces a polycarbonate (PC) film with a unique surface microstructure and verifies its improvement effect on contrast and brightness through experiments. Overview At present, the market's demand for brightness, visual effects and energy consumption of automotive instrument panel lighting and display instruments is constantly increasing. Ordinary transparent or matte printing-grade plastic films have been used to provide the necessary local diffuse reflection effect to cover the light bulbs and structural details behind the display screen, and to allow light to pass through when lighting is required. However, sufficient brightness and contrast need to be achieved by adding additional illumination intensity and proper surface texture treatment. At this time, the application of such films may be limited. It is gratifying that in the LCD TV and display application markets, the latest developments in high-performance optical films have made it possible to extend the adjustment function of these films to certain optical paths to the display and dashboard applications of automobiles. Generally, optical functions are achieved by creating optical microstructures (such as microlens arrays, semi-cylinders, or prism arrays) on the surface of the film. Such films are particularly suitable for applications where LEDs are used as lighting sources. This article evaluated two types of films: one is a film with a microlens array on the surface; the other is a film with a random matte texture (as a reference). The surface of the film was screen printed with a pattern similar to the commonly used instrument panel, placed in a backlight module for testing, and then used light intensity measurement methods to qualitatively and quantitatively evaluate the brightness and contrast of the module. Anyang Kayo Amorphous Technology Co.,Ltd. , https://www.kayoamotech.com
Figure 1 Example of a car display 
Figure 2 Printed PC film for the instrument panel 
Figure 3: Law of refraction: light refraction (for air, n2 = 1)