Light-emitting device having triplet and singlet compound in light-emitting layers
View Patent ↗There is provided a light emitting device which enables a color display with good color balance. A triplet compound is used for a light emitting layer of an EL element that emits red color, and a singlet compound is used for a light emitting layer of an EL element that emits green color and a light emitting layer of an EL element that emits blue color. Thus, an operation voltage of the EL element emitting red color may be made the same as the EL element emitting green color and the EL element emitting blue color. Accordingly, the color display with good color balance can be realized.
1. A light emitting device comprising:
a pixel portion;
a switching thin film transistor in the pixel portion;
a current control thin film transistor in the pixel portion;
at least an EL element electrically connected to the current control thin film transistor in the pixel portion;
wherein the switching thin film transistor is an n-channel thin film transistor;
wherein the current control thin film transistor is a p-channel thin film transistor;
a first pixel including a first EL element for emitting a red light in the pixel portion;
a second pixel including a second EL element for emitting a green light in the pixel portion;
a third pixel including a third EL element for emitting a blue light in the pixel portion;
wherein a triplet compound is used in the first EL element while a singlet compound is used in each of the second and third EL elements.
2. A device according to claim 1 ,
wherein the triplet compound is represented by
3. A device according to claim 2 ,
wherein the element belonging to Groups 8-10 IN the periodic table is one selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
4. A device according to claim 1 ,
wherein the triplet compound is represented by
5. A device according to claim 1 ,
wherein the element belonging to Groups 8-10 in the periodic table is one selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
6. A device according to claim 1 ,
wherein each of the switching thin film transistor and the current control thin film transistor is an inverted stagger thin film transistor.
7. A device according to claim 1 ,
wherein each of the switching thin film transistor and the current control thin film transistor is an inverted stagger thin film transistor.
8. A module using the light emitting device of claim 1 .
9. An electrical apparatus using the light emitting device of claim 1 .
10. A portable telephone using the light emitting device of claim 1 .
11. A digital camera using the light emitting device of claim 1 .
12. An audio equipment using the light emitting device of claim 1 .
13 .A method of operating the EL element of claim 1 in a range of 10V or less.
14. A light emitting device comprising:
a pixel portion;
a switching thin film transistor in the pixel portion;
a current control thin film transistor in the pixel portion;
at least an EL element electrically connected to the current control thin film transistor in the pixel portion;
wherein the switching thin film transistor is a p-channel thin film transistor;
wherein the current control thin film transistor is an n-channel thin film transistor;
a first pixel including a first EL element for emitting a red light in the pixel portion;
a second pixel including a second EL element for emitting a green light in the pixel portion;
a third pixel including a third EL element for emitting a blue light in the pixel portion;
wherein a triplet compound is used in the first EL element while a singlet compound is used in each of the second and third EL elements.
15. A method of operating the EL element of claim 14 in a range of 10V or less.
16. A device according to claim 14 ,
wherein the triplet compound is represented by
17. A device according to claim 16 ,
wherein the element belonging to Groups 8-10 in the periodic table is one selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
18. A device according to claim 14 ,
wherein the triplet compound is represented by
19. A device according to claim 18 ,
wherein the element belonging to Groups 8-10 in the periodic table is one selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
20. A device according to claim 14 ,
wherein each of the switching thin film transistor and the current control thin film transistor is a bottom gate thin film transistor.
21. A device according to claim 14 ,
wherein each of the switching thin film transistor and the current control thin film transistor is an inverted stagger thin film transistor.
22. A module using the light emitting device of claim 14 .
23. An electrical apparatus using the light emitting device of claim 14 .
24. A portable telephone using the light emitting device of claim 14 .
25. A digital camera using the light emitting device of claim 14 .
26. An audio equipment using the light emitting device of claim 14 .
27. A light emitting device comprising:
a pixel portion;
a switching thin film transistor in the pixel portion;
a current control thin film transistor in the pixel portion;
at least an EL element electrically connected to the current control thin film transistor in the pixel portion;
wherein the switching thin film transistor is an n-channel thin film transistor;
wherein the current control thin film transistor is an n-channel thin film transistor;
a first pixel including a first EL element for emitting a red light in the pixel portion;
a second pixel including a second EL element for emitting a green light in the pixel portion;
a third pixel including a third EL element for emitting a blue light in the pixel portion;
wherein a triplet compound is used in the first EL element while a singlet compound is used in each of the second and third EL elements.
28. A method of operating the EL element of claim 27 in a range of 10V or less.
29. A device according to claim 27 ,
wherein the triplet compound is represented by
30. A device according to claim 29 ,
wherein the element belonging to Groups 8-10 in the periodic table is one selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
31. A device according to claim 29 ,
wherein the triplet compound is represented by
32. A device according to claim 31 ,
wherein the element belonging to Groups 8-10 in the periodic table is one selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
33. A device according to claim 27 ,
wherein each of the switching thin film transistor and the current control thin film transistor is a bottom gate thin film transistor.
34. A device according to claim 27 ,
wherein each of the switching thin film transistor and the current control thin film transistor is an inverted stagger thin film transistor.
35. A module using the light emitting device of claim 27 .
36. An electrical apparatus using the light emitting device of claim 27 .
37. A portable telephone using, the light emitting device of claim 27 .
38. A digital camera using the light emitting device of claim 27 .
39. An audio equipment using the light emitting device of claim 27 .
40. A light emitting device comprising:
a pixel portion;
a switching thin film transistor in the pixel portion;
a current control thin film transistor in the pixel portion;
at least an EL element electrically connected to the current control thin film transistor in the pixel portion;
wherein the switching thin film transistor is a p-channel thin film transistor;
wherein the current control thin film transistor is a p-channel thin film transistor;
a first pixel including a first EL element for emitting a red light in the pixel portion;
a second pixel including a second EL element for emitting a green light in the pixel portion;
a third pixel including a third EL element for emitting a blue light in the pixel portion;
wherein a triplet compound is used in the first EL element while a singlet compound is used in each of the second and third EL elements.
41. A method of operating the EL element of claim 40 in a range of 10V or less.
42. A device according to claim 40 ,
wherein the triplet compound is represented by
43. A device according to claim 42 ,
wherein the element belonging to Groups 8-10 in the periodic table is one selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
44. A device according to claim 40 ,
wherein the triplet compound is represented by
45. A device according to claim 44 ,
wherein the element belonging to Groups 8 - 10 in the periodic table is one selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
46. A device according to claim 40 ,
wherein each of the switching thin film transistor and the current control thin film transistor is a bottom gate thin film transistor.
47. A device according to claim 40 ,
wherein each of the switching thin film transistor and the current control thin film transistor is an inverted stagger thin film transistor.
48. A module using the light emitting device of claim 40 .
49. An electrical apparatus using the light emitting device of claim 40 .
50. A portable telephone using the light emitting device of claim 40 .
51. A digital camera using the light emitting device of claim 40 .
52. An audio equipment using the light emitting device of claim 40 .
53. A light emitting device having a pixel portion over a substrate, the pixel portion comprising:
a first EL element for emitting a red light, the first EL element comprising a triplet compound;
a second EL element for emitting a green light; and
a third EL element for emitting a blue light,
wherein at least one of the second EL element and the third EL element comprises a singlet compound.
54. A light emitting device according to claim 53 , wherein the light emitting device is an active matrix type display.
55. A light emitting deivce according to claim 53 , wherein each of the second EL element and the third EL element comprises the singlet compound.
56. A device according to claim 53 ,
wherein the triplet compound is represented by
57. A device according to claim 56 ,
wherein the element belonging to Groups 8-10 in the periodic table is one selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
58. A device according to claim 53 ,
wherein the triplet compound is represented by
59. A device according to clam 58 ,
wherein the element belonging to Groups 8-10 in the periodic table is one selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
60. A modle using the light emitting device according to claim 53 .
61. An electrical apparatus using the light emitting device according to claim 53 .
62. A device according to claim 53 , wherein the device is implemented into at least one selected from the group consisting of a portable telephone, a digital camera and an audio equipment.
63. A method of operating the EL element according to claim 53 in a range of 10V or less.
64. A light emitting device having a pixel portion over a substrate, the pixel portion comprising:
a first EL element for emitting a red light, the first EL element comprising a first electrode, a second electrode and a light emitting layer comprising an organic compound which emits light by a triplet exciton interposed therebetween.
65. A light emitting device according to claim 64 , wherein each of the second EL element and the third EL element comprises the third electrode, the fourth electrode and the light emitting layer comprising the organic compound which emits light by the singlet exciton interposed therebetween.
66. A device according to claim 64 ,
wherein the organic compound which emits light by a triplet exciton is represented
67. A device according to claim 66 ,
whereikn the element belonging to Groups 8-10 in the periodic table is one selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
68. A device according to claim 64 ,
wherein the organic compound which emits light by a triplet exciton is represented by
69. A device according to claim 68 ,
wherein the element belonging to Groups 8-10 in the periodic table is one selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
70. A module using the light emitting device according to claim 64 .
71. An electrical apparatus using the light emitting device according to claim 64 .
72. A device according to claim 64 , wherein the device is implemented into at least one selected from the group consisting of a portable telephone, a digital camera and an audio equipment.
73. A method of operating the EL element according to claim 64 in a range of 10V or less.
74. A light emitting device comprising:
a pixel portion over a substrate;
at least a thin film transistor;
a first EL element for emitting a red light in the pixel portion, the first EL element comprising a triplet compound;
a second EL element for emitting a green light in the pixel portion; and
a third EL element for emitting a blue light in the pixel portion,
wherein at least one of the second EL element and the third EL element comprises a singlet compound.
75. A device according to claim 74 ,
wherein the triplet compound is represented by
76. A device according to claim 75 ,
wherein the element belonging to Groups 8-10 in the periodic table is one selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
77. A device according to claim 74 ,
wherein the triplet compound is represented by
78. A device according ot claim 77 ,
wherein the element belonging to Groups8-10 in the periodic table in one selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
79. A module using the light emitting device according to claim 74 .
80. An electrical apparatus using the light emitting device according to claim 74 .
81. A device according to claim 74 , wherein the device is implemented into a least one selected from the group consisting of a portable telephone, a digital camera and an audio equipment.
82. A method of operating the EL element according to claim 83 in a range of 10V or less.
83. A light emitting device comprising:
a pixel portion over a substrate;
at least a thin film transistor;
a first EL element for emitting a red light in the pixel portion, the first EL element comprising a first electrode, a second electrode and a light emitting layer comprising an organic compound which emits light by a triplet exciton interposed therebetween;
a second EL element for emitting a green light in the pixel portion; and
a third EL element for emitting a blue light in the pixel portion,
wherein at least one of the second EL element and the third EL element comprises a third electrode, a fourth electride and a light emitting layer comprising an organic compound which emits light by a singlet exciton interposed therebetween.
84. A device according to claim 83 ,
wherein the organic compound which emits light by a triplet exciton is represented by
85. A device according to claim 84 ,
wherein the element belonging to Groups 8-10 in the periodic table is one selected from the group consisting of platinum, iridium, nickel, cobalt and palladium,
86. A device according to claim 83 ,
wherein the organic compound which emits light by triplet exciton is represented by
87. A device according to claim 86 ,
wherein the element belonging to Groups 8-10 in the periodic table is one selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
88. A module using the light emitting device according to claim 83 .
89. An electrical apparatus using the light emitting device according to claim 83 .
90. A device according to claim 83 , wherein the device is implemented into at least one selected from the group consisting of a portable telephone, a digital camera and an audio equipment.
91 .A method of operating the EL element according to claim 83 in a range of 10V or less.
92. A light emitting device comprising:
a pixel portin over a substrate;
at least a thin film transistor;
a first EL element for emitting a red light in the pixel portion, the first EL element comprising a triplet compound;
a second EL element for emitting a green light in the pixel portion; and
a third EL element for emitting a blue light in the pixel portion,
wherein each of the second EL element and the third EL element comprise a singlet compound.
93. A device according to claim 92 ,
wherein the triplet compound is represented by
94. A device according to claim 93 ,
wherein the element belonging to Groups 8-10 in the periodic table is on selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
95. A device according to claim 92 ,
wherein the triplet compound is represented by
96. A device according to claim 95 ,
wherein the element belonging to Groups 8-10 in the periodic table is one selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
97. A module using the light emitting device according to claim 92 .
98. An electrical apparatus using the light emitting device according to claim 92 .
99. A device according to claim 92 , wherein the device is implemented into at least one selected from the group consisting of a portable telephone, a digital camera and an audio equipment.
100. A method of operating the EL element according to claim 92 in a range of 10V or less.
101. A light emitting device comprising:
a pixel portion over a substrate;
at least a thin film substrate;
a first EL element for emitting a red light in the pixel portion, the first EL element comprising a first electrode, a second electrode and a light emitting layer comprising an organic compound which emits light by a triplet exciton interposed therebetween;
a second EL element for emitting a green light in the pixel portion; and
a third EL element for emitting a blue light in the pixel portion,
wherein each of the second EL element and the third EL element comprise a third electrode, a fourth electrode and a light emitting layer comprising an organic compound which emits light by a singlet exciton interposed therebetween.
102. A device according to claim 101 ,
wherein the organic compound which emits light by a triplet exciton is represented by
103. A device according to claim 102 ,
wherein the element belonging to Groups 8-10 in the periodic table is one selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
104. A device according to claim 101 ,
wherein the organic compound which emits light by a triplet exciton is represented by
105. A device according to claim 104 ,
wherein the element belonging to Groups 8-10 in the periodic table is selected from the group consisting of platinum, iridium, nickel, cobalt and palladium.
106 .A module using the light emitting device according to claim 101 .
107. An electrical apparatus using the light emitting device according to claim 101 .
108. A device according to claim 101 , wherein the device is implemented into at least at least one selected from the group consisting of a portable telephone, a digital camera and an audio equipment.
109. A method of operating the EL element according to claim 101 in a range 10V or less.