Rubbing alignment method of alignment layer

A rubbing alignment method of an alignment layer, comprising steps of:

• step 1, providing a substrate, and coating an alignment layer on the substrate such that the alignment layer has a surface that is partly recessed to form a sunk area that has a bottom and opposite first and second sidewalls extending between the surface of the alignment layer and the bottom and facing each other, the first and second sidewalls respectively defining first and second corner with respect to the bottom;
• step 2, providing a rubbing roller, and employing the rubbing roller to implement a first rubbing alignment to the alignment layer through first movement with respect to the substrate in a first rubbing direction in which the first movement of the rubbing roller is made toward the first sidewall of the sunk area of the alignment film so that the first corner is rubbed;
• and
• step 3, employing the rubbing roller to implement a second rubbing alignment to the alignment layer through second movement in a second rubbing direction, wherein the second rubbing direction is opposite to the first rubbing direction, wherein the second movement of the rubbing roller in the second direction is made toward the second sidewall of the sunk area of alignment film so that the second corner is rubbed;
• wherein the first and second movements are conducted successively and in opposite first and second rubbing directions and the rubbing roller is arranged such that a center of the rubbing roller is located on the same horizontal plane and is kept at a constant distance from the alignment layer during the successively conducted first and second movements;
• wherein step 3 is implemented to eliminate a rubbing shadow generated in step 2;
• wherein step 2 and step 3 are repeated for multiple times;
• wherein the substrate is a color filter (CF) substrate, and the CF substrate comprises a plurality of pixels arranged in an array, and each pixel comprises a red, a green, a blue, and a white sub pixels;
• color resists of the same thickness are provided corresponding to the red, the green, the blue sub pixels, and a blank area corresponds to the white sub pixel, and a black matrix separates the red, the green, the blue, the white sub pixels;
• wherein the alignment layer is coated on the red, the green, and the blue sub pixels, the blank area of the white sub pixel and the black matrix, such that a part of the alignment layer corresponding to the blank area is recessed and is formed with the sunk area that is located above the blank area of the white sub pixel;
• and
• wherein the rubbing roller comprises a roller body and a rubbing cloth fixed around the roller body, and the roller body moves the rubbing cloth to implement rubbing alignment to the alignment layer.