Electroluminescent device with enhanced color rendition
View Patent ↗To provide an electroluminescent device excellent in color rendition, the electroluminescent device has at least two luminescent local maxima in a visible range, the at least two luminescent local maxima including a first luminescent local maximum and a second luminescent local maximum, the first and second luminescent local maxima have the two largest values of the at least two luminescent local maxima, wherein the electroluminescent device has the first luminescent local maximum in a range of from 450 to 530 nm, and the electroluminescent device has the second local luminescent local maximum in a range of 605 nm or more.
1. An electroluminescent device which comprises:
a pair of electrodes, at least one of the pair of the electrodes being a transparent electrode; and
a light emitting layer between the pair of the electrodes, wherein the light emitting layer comprises: a luminescent layer; a light scattering layer; and a pigment layer in this order, starting from said transparent electrode;
and wherein the electroluminescent device has at least two luminescent local maxima in a visible range,
wherein the electroluminescent device has a first luminescent local maximum in a range of from 477 to 498 nm, and the electroluminescent device has a second luminescent local maximum in a range of 605 nm or more, and
wherein the first and second luminescent local maxima are the two largest of all other luminescent local maxima.
2. The electroluminescent device as claimed in claim 1 , which has the second luminescent local maximum in a range of from 605 to 615 nm.
3. The electroluminescent device as claimed in claim 1 , which has the first luminescent local maximum in a range of from 483 to 493 nm.
4. The electroluminescent device as claimed in claim 3 , wherein the local maxima are the equilibrium points of two colors.
5. The electroluminescent device as claimed in claim 4 , wherein the two colors are green and blue.
6. The electroluminescent device as claimed in claim 1 , which has a luminescent local minimum in a range of from 565 to 583 nm.
7. The electroluminescent device as claimed in claim 1 , which device has a luminescent local minimum in a range of from 571 to 583 nm.
8. The electroluminescent device as claimed in claim 6 or 7 , wherein the local minima are the equilibrium points of two colors.
9. The electroluminescent device as claimed in claim 8 , wherein the two colors are green and red.
10. The electroluminescent device as claimed in claim 1 , which has a ratio of a value of the relative intensity at the first luminescent local maximum to a value of the relative intensity at the second luminescent local maximum of from 2/8 to 8/2.
11. The electroluminescent device as claimed in claim 1 , wherein the light emitting layer includes a dielectric layer.
12. The electroluminescent device as claimed in claim 1 , wherein the light scattering layer has a thickness of from 3 to 15 μm.
13. The electroluminescent device as claimed in claim 1 , wherein the luminescent device has a color temperature of luminescence in a range of 5,000 to 10,000 K.
14. The electroluminescent device as claimed in claim 13 , wherein the luminescent device has a color temperature of luminescence in a range of 6,000 to 10,000 K.
15. The electroluminescent device as claimed in claim 1 , wherein the electroluminescent device is an inorganic electroluminescent device, and wherein the inorganic electroluminescent device comprises a fluorescent particle as a luminescent material.
16. The electroluminescent device as claimed in claim 15 , wherein the fluorescent particle is activated zinc sulfide or activated strontium sulfide.