Printing screen with improving side-bottom ratio
A printing screen, printing process and method for improving side-bottom ratio are provided. The printing screen mainly comprises a plurality of printing units, wherein each of the printing units comprises a body and a protrusion structure. The body has an ink aperture, and the protrusion structure extends from a surface of the body into the ink aperture. The printing process of a fluorescent layer in a plasma display panel utilizing the said printing screen can enhance the uneven film thickness of the fluorescent layer on the bottom of a discharge chamber, and further improve the side-bottom ratio of the fluorescent layer in a plasma display panel.
1. A printing screen, adapted for a printing process of a fluorescent layer in a plasma display panel, wherein the printing screen comprises a plurality of printing units, and each of the printing units comprises:
a body having an ink aperture; and
a protrusion structure extending from a surface of the body into the ink aperture.
2. The printing screen of claim 1 , wherein each of the protrusion structure of each of the printing units comprises a first protrusion and a second protrusion.
3. The printing screen of claim 2 , wherein a shape of the ink aperture comprises a quadrangle.
4. The printing screen of claim 3 , wherein in each of the printing units, the first protrusion and the second protrusion are respectively connected to two neighboring side edges of the quadrangular ink aperture.
5. The printing screen of claim 3 , wherein in each of the printing unit, the first protrusion and the second protrusion are respectively connected to two opposite side edges of the quadrangular ink aperture.
6. The printing screen of claim 5 , wherein a shape of the ink aperture comprises a rectangle and the opposite side edges comprise two short sides of the rectangular ink aperture in each of the printing units.
7. The printing screen of claim 5 , wherein the positions of the first protrusion and the second protrusion are symmetric.
8. The printing screen of claim 5 , wherein the positions of the first protrusion and the second protrusion are asymmetric.
9. The printing screen of claim 1 , wherein the protrusion structure of each of the printing units comprises a plurality of first protrusions and a plurality of second protrusions.
10. The printing screen of claim 9 , wherein a shape of the ink aperture comprises a quadrangle, and each of the quadrangular ink aperture comprises a first vertical side edge, a second vertical side edge, a first horizontal side edge and a second horizontal side edge, and the first vertical side edge is opposite to the second vertical side edge and the first horizontal side edge is opposite to the second horizontal side edge.
11. The printing screen of claim 10 , wherein a shape of the ink aperture comprises a rectangle.
12. The printing screen of claim 10 , wherein in each of the printing units, some first protrusions are connected to the first vertical side edge of the rectangular ink aperture, other first protrusions are connected to the second vertical side edge of the rectangular ink aperture, while some second protrusions are connected to the first horizontal side edge of the rectangular ink aperture, and other second protrusions are connected to the second horizontal side edge of the rectangular ink aperture.
13. The printing screen of claim 12 , wherein the positions of some first protrusions connected to the first vertical side edge of the rectangular ink aperture and other first protrusions connected to the second vertical side edge of the rectangular ink aperture are symmetric.
14. The printing screen of claim 12 , wherein the positions of some first protrusions connected to the first vertical side edge of the rectangular ink aperture and other first protrusions connected to the second vertical side edge of the rectangular ink aperture are asymmetric.
15. The printing screen of claim 12 , wherein the positions of some second protrusions connected to the first horizontal side edge of the rectangular ink aperture and other second protrusions connected to the second horizontal side edge of the rectangular ink aperture are symmetric.
16. The printing screen of claim 12 , wherein the positions of some second protrusions connected to the first horizontal side edge of the rectangular ink aperture and other second protrusions connected to the second horizontal side edge of the rectangular ink aperture are asymmetric.
17. The printing screen of claim 1 , wherein in each of the printing units, an area ratio of the protrusion structure to the ink aperture is between 0.056:1 to 0.120:1.