Organic EL display panel production method
A method for manufacturing an organic EL display panel, including: forming first electrodes over a substrate; defining, above the substrate, pixel formation regions lining up in a row direction and a column direction, by forming banks over the substrate; applying ink to each pixel formation region by causing a plurality of nozzles lining up in a straight line to discharge the ink to the pixel formation regions while displacing the nozzles relative to the substrate in a scanning direction; drying the ink to form functional layers in the pixel formation regions; and forming a second electrode at a position covering the pixel formation regions. In the application of ink, an angle θ between the scanning direction and the row direction is set to more than 0° and less than 90° and each nozzle applies the ink across a plurality of rows of the pixel formation regions.
1. A method for manufacturing an organic EL display panel, the method comprising:
preparing a substrate;
forming a plurality of first electrodes over the substrate;
defining, above the substrate, a plurality of pixel formation regions lining up in a row direction and a column direction to form a matrix, by forming banks over the substrate having the first electrodes formed thereon;
applying ink containing functional material to each of the pixel formation regions by causing a plurality of nozzles lining up in a straight line to discharge the ink to the pixel formation regions while displacing the nozzles relative to the substrate in a scanning direction along a main surface of the substrate;
drying the ink having been applied to form functional layers containing the functional material in the pixel formation regions; and
forming one or more layers, at least including a second electrode, at a position covering the pixel formation regions having the functional layers formed therein, wherein:
in the application of ink, an angle θ between the scanning direction and the row direction is set to more than 0° and less than 90° and each of the nozzles applies the ink across a plurality of rows of the pixel formation regions,
the pixel formation regions are defined to be located at a fixed pitch Dp in the row direction and at a fixed pitch Dp 2 in the column direction,
in the application of ink, the angle θ is set to satisfy:
Dp ×tan θ≠ Dp 2, [Math. 1]
in the application of ink, the angle θ is set to satisfy:
θ
=
sin
-
1
(
N
·
Dn
·
sin
α
Dp
)
[
Math
.
2
]
where Dn denotes a fixed pitch between the nozzles, α denotes an angle between the scanning direction and the straight line, and N is a positive integer,
the pixel formation regions are defined to each include sub-pixel formation regions corresponding to colors red, green, and blue,
ink application with the nozzles is performed separately, by using different inks, for sub-pixel formation regions corresponding to the color red, sub-pixel formation regions corresponding to the color green, and sub-pixel formation regions corresponding to the color blue,
the positive integer N for angle θ defining the scanning direction in application of one of the inks with which luminance is most dependent upon application amount is larger than the positive integer N for angle θ defining the scanning direction in application of each of the other ones of the inks, and
the applying ink step includes (1) obtaining angle θ for each ink of the respective different inks of the sub-pixel formation region, where each angle θ is set using Math. 1 and Math. 2, and (2) using the obtained angles θ to discharge the respective different inks for the sub-pixel formation regions.
2. The method according to claim 1 , wherein
the sub-pixel formation regions are each elongated in a direction orthogonal to the row direction, and
in the application of any of the inks, the angle θ defining the scanning direction is set to more than 0° and less than 45°.
3. The method according to claim 2 , wherein
in the application of any of the inks, the angle θ defining the scanning direction is set to satisfy:
θ
≤
tan
-
1
(
Lsp
Dp
)
[
Math
.
3
]
where Lsp denotes the length of the sub-pixel formation regions in the direction orthogonal to the row direction.
4. The method according to claim 3 , wherein
in the application of any of the inks, the angles A and a defining the scanning direction are set to satisfy:
α≤90°−θ. [Math. 4]
5. The method according to claim 4 , wherein
the main surface of the substrate has a rectangular shape,
the pixel formation regions are defined so that the row direction matches a direction in which long sides of the substrate extend and the column direction matches a direction in which short sides of the substrate extend, and
in the application of any of the inks, the angle θ defining the scanning direction is set to satisfy:
[
H
cos
θ
+
W
sin
θ
L
sin
α
]
=
[
H
L
sin
α
]
[
Math
.
5
]
where W denotes a length of the long sides of the substrate, H denotes a length of the short sides of the substrate, and L denotes a length of the array of the nozzles.
6. The method according to claim 1 , wherein the positive integer N for angle θ defining the scanning direction in application of a green ink with which luminance is most dependent upon application amount is larger than the positive integer N for angle θ defining the scanning direction in application of blue and red inks.