The color source of LCD display color screen
Photoresist, also known as photoresist, refers to a corrosion-resistant film material whose solubility changes through irradiation or radiation by ultraviolet light, electron beam, ion beam, X-ray, etc. Photoresist is the core material of the photolithography process, mainly composed of resin, photoreceptor, solvent, additive, etc., among which resin and photoreceptor are the core parts.
Depending on the application field, photoresist can be divided into semiconductor photoresist, LCD photoresist and PCB photoresist. Among them, in the field of LCD display, photoresist used to make color filters mainly include black photoresist, color photoresist (R, G, B) and transparent photoresist.
1. Color filter technology
Color filter (CF) is a key component of colorization of LCD displays, and its function is to realize the color display of LCD panels. The production methods of color filters include dyeing method, dye dispersion method, electroplating method, printing method, inkjet method, etc. Among them, pigment dispersion method has advantages in color characteristics, quality, and commonality, so it has become the mainstream method for making color filters at present.
Pigment dispersion is a process of uniformly dispersing pigments in a suitable medium to form a uniform pigment suspension and then coating the suspension on the substrate material. The main process flow includes coating, pre-baking, exposure, development, post-baking, etc.
2. Color photoresist components
Photoresist is mainly composed of solvents, resins, photosensitive agents, additives and other components, of which solvents account for about 50% to 90%, resins account for about 10% to 40%, photosensitive agents account for about 1% to 6%, and additives account for about <1%. Colored photoresist mainly adds pigments (5%~10%) and dispersants (5%~10%) on this basis. Pigments are mainly used for the coloring of photoresist, and dispersants are mainly used to disperse the pigments evenly.
Since colored photoresist contains pigments, the technical requirements are higher than that of the photoresist system without pigments, and it requires effective pigment dispersion and stability technology. At the same time, because pigments have light-shielding properties, they need to have a high-sensitivity photolithography resin system. The performance of high-sensitivity photoinitiators and resins play a decisive role in colored photoresist.
3. Preparation of color photoresist
The process flow of color photoresist production includes steps such as raw material preparation, mixing, dispersion, filtration, and barreling. First prepare the raw materials according to the formula, then add the raw materials to the reactor for mixing and stirring until they are evenly stirred, then filter out the large particles in the photoresist through the filter element, and finally pack and store.
4. Color photoresist development
As terminal application products continue to pursue lighter, thinner and high image quality display, in line with this, LCD panels are gradually developing towards high brightness, high contrast, high color saturation, and high resolution. In line with the needs of LCD panels, the development of color photoresist needs to develop in the direction of high transmittance, high color saturation, and high resolution.
1. In line with the high brightness requirements of LCD panels, color photoresist with high transmittance is needed.
2. High color saturation requires the development of high color saturation (NTSC) color photoresist.
3. High resolution requires color photoresist to have the ability to make thi
