Functional layer forming ink and self-luminous element manufacturing method
A functional layer forming ink used in forming a functional layer of the self-luminous element by a printing method, the ink including functional material dissolved or dispersed in a mixed solvent including solvents having different boiling points. When one or more solvents are selected from the solvents of the mixed solvent in descending order of boiling point until a mass ratio of the selection to the mixed solvent is a defined ratio or more, the one or more solvents in the selection are included in a solvent group of solvents that have a contact angle of 5° or less with respect to a defined resin material.
1. An ink used in forming a functional layer of a self-luminous element by a printing method, the ink comprising:
functional material dissolved or dispersed in a mixed solvent including solvents having different boiling points, wherein
when one or more solvents are selected from the solvents of the mixed solvent in descending order of boiling point until a mass ratio of the selection to the mixed solvent is a defined ratio or more, the one or more solvents in the selection are included in a solvent group of solvents that have a contact angle of less than 5° with respect to a defined resin material.
2. The ink of claim 1 , wherein
the defined resin material is acrylic resin.
3. The ink of claim 2 , wherein
the solvents in the solvent group are polar solvents.
4. The ink of claim 2 , wherein
the solvents in the solvent group each satisfy:
x+ 0.04 y< 2.12
where x is δD/(δD+δP+δH), y is surface tension of the solvent in mN/m, and δD is energy due to London dispersion force, δP is energy due to dipole interaction, and δH is energy due to hydrogen bonding, as defined by the Hansen solubility parameter.
5. The ink of claim 1 , wherein
the defined ratio is 0.3 or greater.
6. The ink of claim 1 , wherein
q≥ 0.00086 p+ 0.27512
where p is resolution in ppi of the self-luminous element in a display and q is the defined ratio.
7. The ink of claim 1 , wherein
the mixed solvent includes solvents that have a boiling point of 200° C. or more.
8. A method of manufacturing a self-luminous element comprising:
preparing a substrate;
disposing pixel electrodes in a matrix of rows and columns above the substrate;
forming pixel regulation layers that partition the pixel electrodes in a column direction;
forming banks that partition the pixel electrodes in a row direction;
forming functional layers above the pixel electrodes; and
forming a counter electrode above the functional layers, wherein
the forming of the functional layers includes application of functional layer forming ink onto the pixel electrodes in gaps between the banks and drying the functional layer forming ink after application, and
the functional layer forming ink includes functional material dissolved or dispersed in a mixed solvent including solvents having different boiling points, and
when one or more solvents are selected from the solvents of the mixed solvent in descending order of boiling point until a mass ratio of the selection to the mixed solvent is a defined ratio or more the one or more solvents in the selection are included in a solvent group of solvents that have a contact angle of less than 5° with respect to the pixel regulation layers.
9. The method of claim 8 , wherein
in the forming of the pixel regulation layers, acrylic resin is used as a material of the pixel regulation layers.
10. The method of claim 9 , wherein
the solvents in the solvent group are polar solvents.
11. The method of claim 9 , wherein
the solvents in the solvent group each satisfy:
x+ 0.04 y< 2.12
where x is δD/(δD+δP+δH), y is surface tension of the solvent in mN/m, and δD is energy due to London dispersion force, δP is energy due to dipole interaction, and δH is energy due to hydrogen bonding, as defined by the Hansen solubility parameter.
12. The ink of claim 1 , wherein the contact angle is relative to a surface of the defined resin material, the defined resin material forming one or more pixel regulation layers.