Liquid crystal display device and manufacturing method thereof
Disclosed is a manufacturing method of a liquid crystal display device which is a manufacturing method of a liquid crystal display device including a liquid crystal alignment film to which an alignment regulating force is imparted by a photo-alignment treatment, including: a film forming step of forming a film containing a polymer whose main chain is cleaved by irradiation with light; a photo-alignment step of imparting an alignment regulating force to the film formed in the film forming step by irradiation of the film with light in an atmosphere of a temperature lower than 100° C.; and a removing step of removing a low-molecular weight component generated by cleaving the main chain of the polymer through the light irradiation after the light irradiation. Also disclosed is a liquid crystal display device manufactured by the manufacturing method.
1. A manufacturing method of a liquid crystal display device comprising;
a photo alignment film forming step comprising:
forming a film formed of polyimide having a cyclobutane structure from one of a polyamic acid and a polyamic acid ester;
cleaving the cyclobutane structure of the film by irradiation with light in an atmosphere having a temperature lower than 100° C.; and
removing a low-molecular weight component having a maleimide end which is cleaved from the cyclobutane structure of the film by the light irradiation,
wherein the photo alignment film aligns liquid crystal molecules substantially in parallel with a surface of a substrate,
wherein the removing step comprises the low-molecular weight component is removed by heating the film under a reduced pressure atmosphere after the light irradiation, and
wherein the polyimide is represented by chemical formula (1),
in the formula, R represents a divalent electron donating organic group and n represents the number of repeating units of polymer.
2. The manufacturing method of a liquid crystal display device according to claim 1 ,
wherein the heating in the removing step is performed at 150° C. or higher.
3. The manufacturing method of a liquid crystal display device according to claim 1 ,
wherein the heating in the removing step is performed at 300° C. or less.
4. The manufacturing method of a liquid crystal display device according to claim 1 ,
wherein the heating in the removing step is performed in a temperature range of 200° C. to 290° C.
5. The manufacturing method of a liquid crystal display device according to claim 1 ,
wherein the heating in the removing step is performed for 5 minutes or more.
6. The manufacturing method of a liquid crystal display device according to claim 1 ,
wherein the heating in the removing step is performed for 60 minutes or less.
7. The manufacturing method of a liquid crystal display device according to claim 1 ,
wherein the heating in the removing step is performed for 5 minutes to 15 minutes.
8. The manufacturing method of a liquid crystal display device according to claim 1 ,
wherein the cleaving the cyclobutane structure of the film by irradiation with light is performed in an atmosphere having a temperature lower than 75° C.
9. The manufacturing method of a liquid crystal display device according to claim 1 ,
wherein the cleaving the cyclobutane structure of the film by irradiation with light is performed in an atmosphere having a temperature lower than 50° C.
10. The manufacturing method of a liquid crystal display device according to claim 1 ,
wherein the R is an amino group or an alkoxy group.