Organic light-emitting display apparatus having optimized luminance by controlling thickness variation of emission layer
An organic light-emitting display apparatus capable of a high-quality image including a substrate, a first pixel electrode over the substrate, and a first color emission layer disposed over the first pixel electrode and has an upper surface on which a distance in a direction perpendicular to a surface of the substrate between a highest point and a lowest point is about 400 Å to about 900 Å.
1 . An organic light-emitting display apparatus comprising:
a substrate;
a first pixel electrode over the substrate, the first pixel electrode comprising an upper surface;
a pixel defining layer covering an edge of the first pixel electrode, the pixel defining layer comprising a first opening exposing a portion of the first pixel electrode, the upper surface of the first pixel electrode being substantially planar throughout the first opening; and
a first color emission layer disposed over the first pixel electrode and having an upper surface on which a distance in a direction perpendicular to a surface of the substrate between a highest point and a lowest point is about 400 Å to about 900 Å,
wherein the lowest point on the upper surface of the first color emission layer overlaps the first opening, a distance from the substrate to the upper surface of the first color emission layer at a central portion of the first color emission layer is greater than a distance from the substrate to the upper surface of the first color emission layer at the lowest point of the first color emission layer, the first color emission layer comprises a valley, a distance from the substrate to the upper surface of the first color emission layer at the valley is less than the distance from the substrate to the upper surface of the first color emission layer at the central portion, and, in a plan view, the valley encloses the central portion of the first color emission layer.
2 . The organic light-emitting display apparatus of claim 1 , wherein a wavelength of light emitted by the first color emission layer belongs to a wavelength band of about 450 nm to about 495 nm.
3 . The organic light-emitting display apparatus of claim 1 , further comprising:
a second pixel electrode disposed over the substrate and apart from the first pixel electrode; and
a second color emission layer disposed over the second pixel electrode,
wherein the pixel defining layer covers an edge of the second pixel electrode and comprises a second opening that exposes a portion of the second pixel electrode, and the second color emission layer has an upper surface on which a distance in the direction perpendicular to the surface of the substrate between a highest point and a lowest point at locations overlapping the second opening in the plan view is in a range of about 400 Å to about 1,500 Å.
4 . The organic light-emitting display apparatus of claim 3 , wherein a wavelength of light emitted by the second color emission layer belongs to a wavelength band of about 495 nm to about 570 nm.
5 . The organic light-emitting display apparatus of claim 3 , further comprising:
a third pixel electrode disposed over the substrate and apart from the first pixel electrode and the second pixel electrode; and
a third color emission layer disposed over the third pixel electrode,
wherein the pixel defining layer covers an edge of the third pixel electrode and comprises a third opening that exposes a portion of the third pixel electrode, and the third color emission layer has an upper surface on which a distance in the direction perpendicular to the surface of the substrate between a highest point and a lowest point at locations overlapping the third opening in the plan view is in a range of about 400 Å to about 1,500 Å.
6 . The organic light-emitting display apparatus of claim 5 , wherein a wavelength of light emitted by the third color emission layer belongs to a wavelength band of about 630 nm to about 750 nm.
7 . The organic light-emitting display apparatus of claim 3 ,
wherein
a thickness of the second color emission layer is smallest at a center of the second opening; and
the thickness at the center of the second opening is smaller than a thickness of the second color emission layer at an edge of the second opening.
8 . The organic light-emitting display apparatus of claim 7 , wherein the second color emission layer covers an inner side surface of the second opening.
9 . The organic light-emitting display apparatus of claim 1 , wherein
the first color emission layer covers an inner side surface of the first opening, and
a thickness of the first color emission layer has a “W” shape in a cross-sectional view.
10 . The organic light-emitting display apparatus of claim 9 , wherein a distance from the substrate to an end of the edge of the first color emission layer is greater than the distance from the substrate to the upper surface of the first color emission layer at the central portion of the first color emission layer.