Full color display is an important indicator to verify whether the display is competitive in the market. Therefore, many full-colorization technologies are also applied to O- LED displays. There are usually three types of panel types: RGB pixel independent illumination, light color conversion ( Color Conversion) and Color Filter.
First, RGB pixels are independently illuminated
Independent illumination with luminescent materials is currently the most widely used color mode. It uses a precise metal shadow mask and CCD pixel alignment technology. First, it prepares the red, green and blue primary color illuminating centers, and then adjusts the color mixing ratio of the three color combinations to produce true color, so that the three-color OLED elements are independently illuminated. One pixel. The key to this technology is to improve the color purity and luminous efficiency of the luminescent material, while the metal shadow mask etching technology is also crucial.
At present, the organic small molecule luminescent material AlQ3 is a good green light luminescence small fraction of the material, its green color purity, luminous efficiency and stability are very good. However, the best red light-emitting small molecule material of OLED has a luminous efficiency of only 31 mW and a lifetime of 10,000 hours. The development of blue light-emitting small molecule materials is also very slow and difficult. The biggest bottleneck faced by organic small molecule luminescent materials is the purity, efficiency and longevity of red and blue materials. However, by doping the host luminescent material, blue light and red light with good color purity, luminous efficiency and stability have been obtained.
The advantage of the polymer luminescent material is that it can be adjusted by chemical modification. It has been obtained from blue to green to red in various colors covering the entire visible range, but its lifetime is only one tenth of that of small molecule luminescent materials. Therefore, for high molecular polymers, the luminous efficiency and lifetime of the luminescent materials need to be improved. Continuous development of luminescent materials with excellent performance should be an arduous and long-term issue for material developers.
With the colorization, high resolution and large area of ​​the OLED display, the metal shadow mask etching technology directly affects the quality of the display panel image, so more stringent requirements are placed on the dimensional accuracy and positioning accuracy of the metal shadow mask.