The Color Picture Tube Manufacturing Technology Research And Application Of The Blue Phosphor

Color Picture Tube and Display Tube are one of the main display devices, though other display devices such as liquid crystal, projection tube, PDP plasma display etc have already taken a certain part of market shares, cathode ray tube display device still has great potential market in our country.At present the composition of blue phosphor for cathode ray tube is still ZnS: Ag, Cl, whose manufacture process has to go through ball milling, pigmentation. At present there are problems of low brightness, big drop in brightness with poor dispersion in the dispersion process, and pigment is easy to separate when high amount of pigment is added in the manufacture process.Current manufacturing process is firing, water washing, surface treatment, dispersion, water classification, water washing, drying, sieving, pigmentation, drying, sieving, inspection, and application. Pigmentation is to adhere pigment to the surface of selected phosphor with binders. Pigment separation in the application process final phosphor powder gives rise to the phenomenon of "large absence of phosphor particles" and "aluminum exposure". In order to raise the pigmentation ratio, if simply increase the amount of binder, then it will cause the difficult sieving in the process of phosphor manufacture, and at the same time the coating performance of blue phosphor will get worse, poor density and poor cutting will appear. How to raise the amount of pigment added to the phosphor and maintain a good pigmentation, keep the brightness and dispersability is the key problem.This dissertation describes the structure of color picture tube and its requirement on phosphor, and its manufacture process. It has studied the difficult problems for present color phosphor manufacturing process from firing, dispersion, and pigmentation. The results of research work on manufacturing process of present color phosphor are as below.1. It studies the functions of main materials in the mixture as well as its influences on luminescence characteristics, the influences of firing condition on luminescence, particle size.2. Found a new ball milling condition in the ball milling process. Through decreasing the diameter of beads, the dispersion state of phosphor powder is increased and brightness of phosphor powder is kept unchanged, time for dispersing phosphor is decreased. proposes that highly dispersed phosphor can mostly satisfy the requirements to produce good coating results under the condition that luminescence characteristics of industrial production are guaranteed. Raising the dispersability of phosphor powder is the essential requirement to make good phosphor particles.3. This dissertation has proposed its solutions to the difficult pigmentation problems, especially on the high concentration pigmentation problem. It can solve part of the problems of flashing of tubes, clogging of shadow mask which are caused by the pigment separation of phosphor slurry. Found a new method increasing the pigment adherence. G, A binders pigmentation is the most often used method. The new method has improved the pigment separation problem through applying polyacrylamide4. Increase the pigmentation strength by applying G, A binders and latex. In order to increase the pigmentation ratio, small amount of latex is used to the solution of G, A solution which in turn raises the pigmentation effects.