With the development of display technology, the liquid crystal display has become the most commonly used display device.
The liquid crystal display mainly comprises a backlight module, a lower polarizer, an array substrate, a liquid crystal layer, a color film substrate, an upper polarizer, and other components. The brightness of the liquid crystal display depends on the brightness of the backlight emitted by the backlight module, and the utilization ratio of the backlight, which is dependent on the structure of the liquid crystal electric field, the penetration of the liquid crystal material, the aperture ratio of the panel, the penetration of the color film, the penetration of the polarizer and other factors. The backlight emitted by the backlight module comprises the polarized light with various polarization directions, which would be changed into the polarized light with one single polarization direction after passing through the lower polarizer. However, approximately half of the backlight would be lost during this process.
Therefore, how to improve the utilization ratio of the backlight has become an important issue during the design and production of liquid crystal display devices.