The reason why the TFT LCD panel can produce color changes is mainly from the color filter (Color Filter; CF); the so-called liquid crystal panel is through the change of the voltage of the driving IC, so that the liquid crystal molecules stand or twist to form a gate To select whether the backlight light penetrates or not, thus generating a picture, the picture presented at this time is only black and white, and the red (R), green (G), and blue ( B) The three color layers provide hue to form a color display screen.

The manufacturing methods of color filters include dyeing method, pigment dispersion method, printing method, electroplating method, inkjet method, etc. Among them, the pigment dispersion method has advantages in color characteristics, quality, and reliability, so it has become the current color filter. The mainstream production method of optical film, and the color filter manufacturing process of the so-called pigment dispersion method includes black matrix engineering, RGB engineering, post-engineering, shipping engineering, first in the black matrix engineering, first in the alkali-free boron glass substrate Sputtering is used to form a low-reflection two-layer film of chromium oxide / chromium, which is used as a substrate. This low-reflection two-layer film is called Metal Black. Then, the positive photoresist on the side of Metal Black is spin-coated (Spin Coating), after irradiating ultraviolet rays through the black matrix mask pattern, exposing it, and developing the photoresist, the Metal Black is etched to form a black matrix (BM) pattern, after which the black matrix pattern is formed, and then to RGB Engineering, the so-called RGB project is the project of forming R, G, and B three-color patterns in the opening. First, the color photoresist colored in R is painted with Spin, through the pattern mask for R, irradiated with ultraviolet rays and exposed, and then used alkali The non-exposed part is removed by the sexual developer to form the R pattern for the first color, and then applied to the post-baking at 200 degrees Celsius or more to make the pattern resistant, and then the same process of forming the R pattern Repeating on G and B, each pattern is separated by a black matrix. This function is to increase the contrast during display and avoid the generation of colored light. Then, in the post-engineering aspect, the opposite electrode of the TFT Array substrate is formed. The ITO transparent electrode layer is the color filter. Finally, the shipment process is the final inspection and packaging.

The key to the color filter process technology is the step difference between the RGB three colors. The step difference will affect the performance of the liquid crystal. If the step difference is too large, there will be a fault. In addition, the RGB project is a high-temperature process, so the selection of raw materials must be resistant The medicinal properties will not decline, and then the BM is mainly to isolate the RGB three colors, which is the key to improving the color contrast, and the BM generally requires low reflection. The lower the reflection, the better the color performance.