US 11,844,257 B2
Capping layer for tandem structure and display device having the same
Solji Kim, Suwon-si (KR); Jungjin Yang, Seoul (KR); Donghoon Kim, Suwon-si (KR); Jin Woo Park, Yongin-si (KR); Jinsook Bang, Hwaseong-si (KR); Seokjae Lee, Seongnam-si (KR); Sunhye Lee, Hwaseong-si (KR); and Sanghoon Yim, Suwon-si (KR)
Assigned to SAMSUNG DISPLAY CO., LTD., Gyeonggi-Do (KR)
Filed by Samsung Display Co., LTD., Yongin-si (KR)
Filed on Jun. 15, 2021, as Appl. No. 17/347,851.
Claims priority of application No. 10-2020-0143723 (KR), filed on Oct. 30, 2020.
Prior Publication US 2022/0140015 A1, May 5, 2022
Int. Cl. H10K 59/35 (2023.01); H10K 50/19 (2023.01); H10K 50/852 (2023.01)
CPC H10K 59/35 (2023.02) [H10K 50/19 (2023.02); H10K 50/852 (2023.02)] 18 Claims
OG exemplary drawing
 
1. A display device comprising:
a plurality of pixel areas each having a stack structure including a number of stacks defined by a number of organic light emitting layers within the stack structure, the plurality of pixel areas including a first pixel area, a tandem pixel area adjacent to the first pixel area, and a second pixel area which is between the first pixel area and the tandem pixel area;
in the first pixel area:
a first pixel electrode;
a first organic light emitting layer which emits light having a first color; and
the stack structure of the first pixel area having one stack including the first organic light emitting layer;
in the tandem pixel area:
a tandem pixel electrode in a same layer as the first pixel electrode;
a first tandem organic light emitting layer which emits light having a second color different from the first color;
a second tandem organic light emitting layer which faces the tandem pixel electrode with the first tandem organic light emitting layer therebetween and emits light having the second color; and
the stack structure of the tandem pixel area having two stacks as including a greater number of organic light emitting layers than the number of organic light emitting layers of the first pixel area, the two stacks including both the first tandem organic light emitting layer and the second tandem organic light emitting layer;
in the second pixel area:
a second pixel electrode in a same layer as the first pixel electrode and the tandem pixel electrode;
a second organic light emitting layer which emits light having a third color different from the first color and the second color; and
the stack structure of the second pixel area having one stack including the second organic light emitting layer, the one stack including a smaller number of organic light emitting layers than the number of organic light emitting layers of the tandem pixel area;
a capping layer including a thickness at the first pixel area, a thickness at the second pixel area and a thickness at the tandem pixel area;
a common electrode between the capping layer and the first organic light emitting layer, between the capping layer and the second organic light emitting layer and between the capping layer and the second tandem organic light emitting layer,
wherein the thickness of the capping layer at the tandem pixel area is smaller than the thickness of the capping layer at the first pixel area, and
wherein the thicknesses of the capping layer are respectively inverse to the number of stacks of the first pixel area, the tandem pixel area and the second pixel area.