Organic light emitting display device for enhancing efficiency

Abstract

Disclosed is an organic light emitting display device. The organic light emitting display device includes a first emission part between a first electrode and a second electrode and a second emission part on the first emission part. The first emission part includes a first hole transport layer and a first emission layer, and the second emission part includes a second hole transport layer and a second emission layer. A thickness of the second hole transport layer is greater than a thickness of the first hole transport layer.

What is claimed is: 
     
       1. An organic light emitting display device comprising:
 a first emission part between a first electrode and a second electrode, the first emission part including a hole injection layer, a first hole transport layer and a on the hole injection layer, first emission layer on the first hole transport layer, and a first electron transport layer on the first emission layer; and 
 a second emission part on the first emission part, the second emission part including a second hole transport layer on the first emission layer and a second emission layer on the second hole transport layer, 
 wherein the hole injection layer is provided between the first electrode and the first hole transport layer, the first hole transport layer is provided between the hole injection layer and the first emission layer, and the second hole transport layer is provided between the first electron transport layer and the second emission layer, 
 wherein a thickness of the second hole transport layer is greater than a thickness of the first hole transport layer. 
 
     
     
       2. The organic light emitting display device of  claim 1 , wherein the thickness of the first hole transport layer is 20 nm or less. 
     
     
       3. The organic light emitting display device of  claim 1 , wherein the first emission part further comprises an electron blocking layer. 
     
     
       4. The organic light emitting display device of  claim 3 , wherein a thickness of the electron blocking layer is greater than the thickness of the first hole transport layer, the thickness of the electron blocking layer being within a particular range that results in enhanced efficiency of the first emission layer in comparison with a conventional electron blocking layer having a thickness outside of the particular range. 
     
     
       5. The organic light emitting display device of  claim 3 , wherein a sum of the thickness of the first hole transport layer and a thickness of the electron blocking layer is 40 nm or less. 
     
     
       6. The organic light emitting display device of  claim 3 , wherein the first hole transport layer and the electron blocking layer are formed of a same material. 
     
     
       7. The organic light emitting display device of  claim 3 , wherein a triplet energy level of the electron blocking layer is within a range of 2.7 eV to 2.9 eV. 
     
     
       8. The organic light emitting display device of  claim 3 , wherein a triplet energy level of the electron blocking layer is greater than a triplet energy level of the first hole transport layer, and a thickness of the electron blocking layer is 30 nm or less. 
     
     
       9. The organic light emitting display device of  claim 3 , further comprising: a third emission part on the second emission part, the third emission part including a third hole transport layer and a third emission layer. 
     
     
       10. The organic light emitting display device of  claim 9 , wherein a thickness of the third hole transport layer is less than a the thickness of the second hole transport layer. 
     
     
       11. The organic light emitting display device of  claim 9 , wherein at least one among the first hole transport layer and the third hole transport layer comprises a material having a triplet energy level within a same range as a range of a triplet energy level of the electron blocking layer. 
     
     
       12. The organic light emitting display device of  claim 9 , wherein when the third hole transport layer includes a material having a triplet energy level within a same range as a range of a triplet energy level of the electron blocking layer of the first emission part, a thickness of the electron blocking layer in the first emission part is less than the thickness of the first hole transport layer. 
     
     
       13. The organic light emitting display device of  claim 9 , wherein at least one among the first emission layer and the third emission layer includes one among a blue emission layer, a deep blue emission layer, and a sky blue emission layer. 
     
     
       14. The organic light emitting display device of  claim 1 , wherein at least one among the first electrode and the second electrode is a semitransmissive electrode. 
     
     
       15. An organic light emitting display device comprising:
 a first emission part between a first electrode and a second electrode, the first emission part including a hole injection layer, a first hole transport layer on the hole injection layer, an electron blocking layer on the first hole transport layer, and a first emission layer on the electron blocking layer; and 
 a second emission part on the first emission part, the second emission part including a second hole transport layer on the first emission layer and a second emission layer on the second hole transport layer, 
 wherein the hole injection layer is provided between the first electrode and the first hole transport layer, the first hole transport layer is provided between the hole injection layer and the electron blocking layer, and the electron blocking layer is provided between the first hole transport layer and the first emission layer, 
 wherein a thickness of the first hole transport layer is less than a thickness of the electron blocking layer. 
 
     
     
       16. The organic light emitting display device of  claim 15 , wherein a sum of the thickness of the first hole transport layer and the thickness of the electron blocking layer is 40 nm or less. 
     
     
       17. The organic light emitting display device of  claim 15 , wherein a triplet energy level of the electron blocking layer is higher than a triplet energy level of the first hole transport layer. 
     
     
       18. The organic light emitting display device of  claim 15 , wherein the first hole transport layer and the electron blocking layer are formed of a same material. 
     
     
       19. The organic light emitting display device of  claim 15 , further comprising: a third emission part on the second emission part, the third emission part including a third hole transport layer and a third emission layer. 
     
     
       20. The organic light emitting display device of  claim 19 , wherein at least one among the first hole transport layer and the third hole transport layer comprises a material having a triplet energy level within a same range as a range of a triplet energy level of the electron blocking layer. 
     
     
       21. The organic light emitting display device of  claim 19 , wherein at least one among the first emission layer and the third emission layer inludes  includes one among a blue emission layer, a deep blue emission layer, and a sky blue emission layer. 
     
     
       22. The organic light emitting display device of  claim 19 , wherein a thickness of the third hole transport layer is less than a thickness of the second hole transport layer. 
     
     
       23. The organic light emitting display device of  claim 15 , wherein a thickness of the second hole transport layer is greater than the thickness of the first hole transport layer. 
     
     
       24. The organic light emitting display device of  claim 15 , wherein at least one among the first electrode and the second electrode is a semitransmissive electrode. 
     
     
       25. The organic light emitting display device of  claim 1 , wherein the first emission layer is configured to emit blue light. 
     
     
       26. The organic light emitting display device of  claim 25 , wherein the blue light comprises a light having a wavelength in a range from 440 nm to 480 nm. 
     
     
       27. The organic light emitting display device of  claim 1 , wherein the second emission layer is configured to emit blue light. 
     
     
       28. The organic light emitting display device of  claim 1 , wherein the second emission layer is configured to emit green light. 
     
     
       29. The organic light emitting display device of  claim 28 , wherein the green light comprises a light having a wavelength in a range from 510 nm to 580 nm. 
     
     
       30. The organic light emitting display device of  claim 1 , further comprising a third emission part on the second emission part, the third emission part including a third hole transport layer and a third emission layer, wherein the thickness of the second hole transport layer and a thickness of the third hole transport layer is greater than the thickness of the first hole transport layer. 
     
     
       31. The organic light emitting display device of  claim 30 , wherein at least one of the second emission layer and the third emission layer is configured to emit blue light, and a remaining one of the second emission layer and the third emission layer is configured to emit green light. 
     
     
       32. The organic light emitting display device of  claim 1 , wherein the first emission part comprises a first electron transport layer on the first emission layer, and wherein the second emission part comprises a second electron transport layer on the second emission layer. 
     
     
       33. The organic light emitting display device of  claim 1 , wherein the first electrode comprises one or a combination of Ag and indium tin oxide (ITO), and is formed as a multi-layer structure. 
     
     
       34. The organic light emitting display device of  claim 1 , wherein the second electrode comprises one or a combination of Ag and Mg, and is formed as a multi-layer structure. 
     
     
       35. The organic light emitting display device of  claim 1 , further comprising a charge generation layer (CGL) disposed between the first emission part and the second emission part. 
     
     
       36. The organic light emitting display device of  claim 35 , wherein the CGL comprises an N-type CGL and a P-type CGL. 
     
     
       37. The organic light emitting display device of  claim 36 , wherein the N-type CGL comprises an organic layer having an alkali metal material or an alkali earth metal material. 
     
     
       38. The organic light emitting display device of  claim 37 , wherein the alkali metal material or the alkali earth metal material comprises lithium, sodium, potassium, cesium, magnesium, strontium, barium, or radium. 
     
     
       39. The organic light emitting display device of  claim 36 , wherein the P-type CGL comprises an organic layer having a P-type dopant. 
     
     
       40. The organic light emitting display device of  claim 1 , further comprising a transistor disposed between a substrate and the first emission part, wherein the transistor comprises a gate electrode, an active layer, a source electrode, and a drain electrode. 
     
     
       41. The organic light emitting display device of  claim 40 , wherein the gate electrode, the source electrode, and/or the drain electrode comprises at least one of molybdenum, aluminum, chromium, gold, titanium, nickel, neodymium, copper, and transparent conductive oxide (TCO). 
     
     
       42. The organic light emitting display device of  claim 40 , further comprising a passivation layer on the source electrode and the drain electrode of the transistor, wherein the passivation layer is formed of one or a combination of SiOx or SiNx. 
     
     
       43. The organic light emitting display device of  claim 40 , further comprising an encapsulation layer including a plurality of layers where an inorganic material and an organic material are alternately stacked. 
     
     
       44. The organic light emitting display device of  claim 43 , further comprising an encapsulation substrate on the encapsulation layer, wherein a color filter is formed on the encapsulation substrate. 
     
     
       45. The organic light emitting display device of  claim 40 , further comprising one or more power lines on the substrate, a data line and a gate line on the substrate electrically connected to the transistor, and wherein the one or more power lines extend parallel with the data line and the gate line. 
     
     
       46. The organic light emitting display device of  claim 1 , wherein at least one of the first emission layer and the second emission layer comprises a plurality of emission layers. 
     
     
       47. The organic light emitting display device of  claim 46 , wherein the plurality of emission layers is configured to emit a first light having a first wavelength range and a second light having a second wavelength range. 
     
     
       48. The organic light emitting display device of  claim 47 , wherein the first wavelength range of the first light is different from the second wavelength range of the second light. 
     
     
       49. The organic light emitting display device of  claim 47 , wherein the first light and/or the second light comprises one of a blue light, a deep blue light, a sky blue light, a red light, a green light, and a yellow-green light. 
     
     
       50. The organic light emitting display device of  claim 47 , wherein the first wavelength range and/or the second wavelength range comprises or overlaps at least one of 440 nm to 480 nm, 480 nm to 590 nm, or 590 nm to 650 nm. 
     
     
       51. The organic light emitting display device of  claim 1 , wherein the first emission part includes the first emission layer and a third emission layer, the second emission part includes the second emission layer and a fourth emission layer. 
     
     
       52. The organic light emitting display device of  claim 51 , further comprising a third emission part on the second emission part, wherein the third emission part includes a fifth emission layer and a sixth emission layer. 
     
     
       53. The organic light emitting display device of  claim 1 , further comprising:
 a color filter on the second emission part; and   a black matrix on the on the second emission part.   
     
     
       54. The organic light emitting display device of  claim 53 , wherein the color filter is disposed between the black matrix. 
     
     
       55. The organic light emitting display device of  claim 53 , wherein a light emitted from the first emission part and the second emission part passes through the color filter. 
     
     
       56. The organic light emitting display device of  claim 53 , wherein the first electrode is electrically connected to a transistor on a substrate through a contact hole in a passivation layer disposed between the substrate and the first electrode, wherein the color filter overlaps the contact hole. 
     
     
       57. The organic light emitting display device of  claim 53 , wherein a thickness of the color filter is the same as a thickness of the black matrix.