Organic electroluminescent element
View Patent ↗An organic electroluminescent element in accordance with the present invention includes: a transparent electrode; a blue light-emitting layer containing a blue light-emitting material having a maximum emission wavelength 460 nm or less; a first green light-emitting layer containing a first green light-emitting material having a maximum emission wavelength in the spectrum between 460 nm and 610 nm; a red light-emitting layer containing a red light-emitting material having a maximum emission wavelength of 610 nm or more; a second green light-emitting layer containing a second green light-emitting material having a maximum emission wavelength in the spectrum between 460 nm and 610 nm; and a reflecting electrode. The maximum emission wavelength of the first green light-emitting material is located on a short wavelength side of the spectrum. The maximum emission wavelength of the second green light-emitting material is located on a long wavelength side of the spectrum.
1. An organic electroluminescent element comprising:
a transparent electrode;
a fluorescent light-emitter including a blue light-emitting layer and a first green light-emitting layer, the blue light-emitting layer containing a blue light-emitting material having a maximum emission wavelength 460 nm or less, the first green light-emitting layer containing a first green light-emitting material having a maximum emission wavelength in a spectrum between 460 nm and 610 nm;
a phosphorescent light-emitter including green light-emitting layer and a red light-emitting layer, the red light-emitting layer containing a red light-emitting material having a maximum emission wavelength of 610 nm or more, the second green light-emitting layer containing a second green light-emitting material having a maximum emission wavelength in the spectrum between 460 nm and 610 nm; and
a reflecting electrode,
wherein:
the maximum emission wavelength of the first green light-emitting material is located on a short wavelength side of the spectrum;
the maximum emission wavelength of the second green light-emitting material is located on a long wavelength side of the spectrum;
the blue light-emitting material and the first green light-emitting material are fluorescent light-emitting materials;
the second green light-emitting material and the red light-emitting material are phosphorescent light emitting materials; and
the fluorescent light-emitter and the phosphorescent light-emitter are stacked such that an intermediate layer is interposed between the fluorescent light-emitter and the phosphorescent light-emitter.
2. The organic electroluminescent element according to claim 1 , wherein:
the maximum emission wavelength of the first green light-emitting material is present between 460 nm and 540 nm; and
the maximum emission wavelength of the second green light-emitting material is present between 540 nm and 610 nm.
3. The organic electroluminescent element according to claim 1 , wherein
a half width of an emission spectrum of at least one of the first green light-emitting material and the second green light-emitting material is 60 nm or more.
4. The organic electroluminescent element according to claim 1 , wherein
a difference between the maximum emission wavelength of the first green light-emitting material and the maximum emission wavelength of the second green light-emitting material is 35 nm or more.
5. The organic electroluminescent element according to claim 1 , wherein:
the fluorescent light-emitter is disposed close to the transparent electrode; and
the phosphorescent light-emitter is disposed close to the reflecting electrode.
6. An organic electroluminescent element comprising:
a transparent electrode;
a fluorescent light-emitter including a blue light-emitting layer and a first green light-emitting layer, the blue light-emitting layer containing a blue light-emitting material having a maximum emission wavelength 460 nm or less, the first green light-emitting layer containing a first green light-emitting material having a maximum emission wavelength between 460 nm and 540 nm;
a phosphorescent light-emitter including a second green light-emitting layer and a red light-emitting layer, the second green light-emitting layer containing a second green light-emitting material having a maximum emission wavelength between 540 nm and 610 nm, the red light-emitting layer containing a red light-emitting material having a maximum emission wavelength of 610 nm or more; and
a reflecting electrode,
wherein:
a quotient of an emission intensity of the second green light-emitting layer divided by an emission intensity of the red light-emitting layer is 0.66 or less;
a quotient of an emission intensity of the blue light-emitting layer divided by an emission intensity of the red light-emitting layer is 0.20 or more;
the organic electroluminescent element is designed to emit light having a color temperature in a range of 2500 K to 3500 K;
the blue light-emitting material and the first green light-emitting material are fluorescent light-emitting materials;
the second green light-emitting material and the red light-emitting material are phosphorescent light-emitting materials;
the fluorescent light-emitter and the phosphorescent light-emitter are stacked such that an intermediate layer is interposed between the fluorescent light-emitter and the phosphorescent light-emitter.
7. The organic electroluminescent element according to claim 6 , wherein
a half width of an emission spectrum of at least one of the first green light-emitting material and the second green light-emitting material is 60 nm or more.
8. The organic electroluminescent element according to claim 6 , wherein
a difference between the maximum emission wavelength of the first green light-emitting material and the maximum emission wavelength of the second green light-emitting material is 35 nm or more.
9. The organic electroluminescent element according to claim 6 , wherein:
the fluorescent light-emitter is disposed close to the transparent electrode; and
the phosphorescent light-emitter is disposed close to the reflecting electrode.
10. An organic electroluminescent element comprising:
a transparent electrode;
a blue light-emitting layer containing a blue light-emitting material having a maximum emission wavelength 460 nm or less;
a first green light-emitting layer containing a first green light-emitting material having a maximum emission wavelength in a spectrum between 460 nm and 610 nm;
a red light-emitting layer containing a red light-emitting material having a maximum emission wavelength of 610 nm or more;
a second green light-emitting layer containing a second green light-emitting material having a maximum emission wavelength in the spectrum between 460 nm and 610 nm; and
a reflecting electrode,
wherein:
the maximum emission wavelength of the first green light-emitting material is located on a short wavelength side of the spectrum;
the maximum emission wavelength of the second green light-emitting material is located on a long wavelength side of the spectrum; and
the organic electroluminescent element has a special color rendering index R9 which is more than 30.
11. The organic electroluminescent element according to 10 , wherein:
the blue light-emitting material and the first green light-emitting material are fluorescent light-emitting materials; and
the second green light-emitting material and the red light-emitting material are phosphorescent light-emitting materials.
12. The organic electroluminescent element according to 11 , wherein
a fluorescent light-emitter including the blue light-emitting layer and the first green light-emitting layer, and a phosphorescent light-emitter including the second green light-emitting layer and the red light-emitting layer are stacked such that an intermediate layer is interposed between the fluorescent light-emitter and the phosphorescent light-emitter.
13. The organic electroluminescent element according to 12 , wherein:
the fluorescent light-emitter is disposed closer to the transparent electrode than the phosphorescent light-emitter; and
the phosphorescent light-emitter is disposed closer to the reflecting electrode than the fluorescent light-emitter.