An organic light emitting display panel comprising: a substrate including an active area configured to display an image, and a non-active area configured not to display the image; an insulating film disposed on the substrate, the insulating film including at least one concave portion in the active area, the concave portion having a flat portion (CONP), an inclined portion (CONS) that extends from the flat portion and surrounds the flat portion, and a side portion (INSS) that extends from the inclined portion and is farther from the substrate than the flat portion; a first electrode disposed on the side portion, the inclined portion, and the flat portion of the concave portion of the insulating film; a bank (BANK) including a first part, a second part, and a third part, wherein the first part is disposed on the first electrode and overlaps with a portion of the flat portion of the concave portion, the second part extends from the first part and overlaps with the inclined portion of the concave portion, and the third part extends from the second part and overlaps with the side portion, wherein a width of the first part of the bank in a direction parallel with an upper surface of the substrate, W1, is greater than a width of the second part of the bank in the direction parallel with the upper surface of the substrate, W2; an organic light emitting layer on the first electrode and the bank, wherein the organic light emitting layer overlaps with the concave portion of the insulating film; and a second electrode disposed on the organic light emitting layer and the bank, wherein the second electrode overlaps with the concave portion of the insulating film; wherein the first electrode is reflective; wherein the width W1 is a distance between an upper surface of the first electrode and a side surface of the first part of the bank in the direction parallel with the upper surface of the substrate and the width W2 is a distance between an upper surface of the first electrode and an upper surface of the second part of the bank in the direction parallel with the upper surface of the substrate, and wherein a ratio of the width of the second part of the bank in the direction parallel with the upper surface of the substrate, to the width of the first part of the bank in the direction parallel with the upper surface of the substrate, is in a range from 1:1.5 to 1:4. a substrate including an active area configured to display an image, and a non-active area configured not to display the image; an insulating film disposed on the substrate, the insulating film including at least one concave portion in the active area, the concave portion having a flat portion (CONP), an inclined portion (CONS) that extends from the flat portion and surrounds the flat portion, and a side portion (INSS) that extends from the inclined portion and is farther from the substrate than the flat portion; a first electrode disposed on the side portion, the inclined portion, and the flat portion of the concave portion of the insulating film; a bank (BANK) including a first part, a second part, and a third part, wherein the first part is disposed on the first electrode and overlaps with a portion of the flat portion of the concave portion, the second part extends from the first part and overlaps with the inclined portion of the concave portion, and the third part extends from the second part and overlaps with the side portion, wherein a width of the first part of the bank in a direction parallel with an upper surface of the substrate, W1, is greater than a width of the second part of the bank in the direction parallel with the upper surface of the substrate, W2; an organic light emitting layer on the first electrode and the bank, wherein the organic light emitting layer overlaps with the concave portion of the insulating film; and a second electrode disposed on the organic light emitting layer and the bank, wherein the second electrode overlaps with the concave portion of the insulating film; wherein the first electrode is reflective; wherein the width W1 is a distance between an upper surface of the first electrode and a side surface of the first part of the bank in the direction parallel with the upper surface of the substrate and the width W2 is a distance between an upper surface of the first electrode and an upper surface of the second part of the bank in the direction parallel with the upper surface of the substrate, and wherein a ratio of the width of the second part of the bank in the direction parallel with the upper surface of the substrate, to the width of the first part of the bank in the direction parallel with the upper surface of the substrate, is in a range from 1:1.5 to 1:4.