Organic EL display panel, display device incorporating same, and organic EL display panel manufacturing method
An organic EL display panel includes light-reflective electrodes, a first red light-emitting layer, a green light-emitting layer, a first blue light-emitting layer, a second red light-emitting layer, a charge generating layer, a second blue light-emitting layer, and a light-transmissive electrode. In a red and a white sub-pixel region, a first optical length is from 20 nm to 50 nm, and a second optical length is from 210 nm to 230 nm. In a green sub-pixel region, the first optical length is from 20 nm to 50 nm, and the second optical length is from 240 nm to 295 nm. In a blue sub-pixel region, the first optical length is from 20 nm to 60 nm, and the second optical length is from 195 nm to 205 nm.
1. An organic electroluminescence (EL) display panel comprising:
a substrate;
a plurality of banks, disposed above the substrate, that define a red sub-pixel region, a green sub-pixel region, a blue sub-pixel region, and a white sub-pixel region;
a plurality of light-reflective electrodes, disposed above the substrate in the red sub-pixel region, the green sub-pixel region, the blue sub-pixel region, and the white sub-pixel region, each of the light-reflective electrodes having a light-reflective surface;
a first red light-emitting unit disposed above a first one of the light-reflective electrodes in the red sub-pixel region, the first red light-emitting unit including a first red light-emitting layer comprising a material that has an emission peak in a red wavelength band, the first red light-emitting layer having a light-emitting surface that faces the light-reflective surface of the first one of the light-reflective electrodes;
a first green light-emitting unit disposed above a second one of the light-reflective electrodes in the green sub-pixel region, the first green light-emitting unit including a green light-emitting layer comprising a material that has an emission peak in a green wavelength band, the green light-emitting layer having a light-emitting surface that faces the light-reflective surface of the second one of the light-reflective electrodes;
a first blue light-emitting unit disposed above a third one of the light-reflective electrodes in the blue sub-pixel region, the first blue light-emitting unit including a first blue light-emitting layer comprising a material that has an emission peak in a blue wavelength band, the first blue light-emitting layer having a light-emitting surface that faces the light-reflective surface of the third one of the light-reflective electrodes;
a second red light-emitting unit disposed above a fourth one of the light-reflective electrodes in the white sub-pixel region, the second red light-emitting unit including a second red light-emitting layer comprising a material that has an emission peak in a red wavelength band, the second red light-emitting layer having a light-emitting surface that faces the light-reflective surface of the fourth one of the light-reflective electrodes;
a charge generating layer disposed above the first red light-emitting unit, the first green light-emitting unit, the first blue light-emitting unit, and the second red light-emitting unit in the red sub-pixel region, the green sub-pixel region, the blue sub-pixel region, and the white sub-pixel region;
a second blue light-emitting unit disposed above the charge generating layer in the red sub-pixel region, the green sub-pixel region, the blue sub-pixel region, and the white sub-pixel region, the second blue light-emitting unit including a second blue light-emitting layer comprising a material that has an emission peak in a blue wavelength band, the second blue light-emitting layer having light-emitting surfaces that each face corresponding ones of the light-reflective surfaces of the light-reflective electrodes;
a light-transmissive electrode disposed above the second blue light-emitting unit in the red, the green, the blue, and the white sub-pixel regions; and
a color filter layer that includes a red filter disposed above the first one of the light-reflective electrodes in the red sub-pixel region, a green filter disposed above the second one of the light-reflective electrodes in the green sub-pixel region, and a blue filter disposed above the third one of the light-reflective electrodes in the blue sub-pixel region, wherein
in the red sub-pixel region, an optical length between the light-emitting surface of the first red light-emitting layer and the light-reflective surface of the first one of the light-reflective electrodes is from 20 nm to 50 nm,
in the green sub-pixel region, an optical length between the light-emitting surface of the green light-emitting layer and the light-reflective surface of the second one of the light-reflective electrodes is from 20 nm to 50 nm,
in the blue sub-pixel region, an optical length between the light-emitting surface of the first blue light-emitting layer and the light-reflective surface of the third one of the light-reflective electrodes is from 20 nm to 60 nm,
in the white sub-pixel region, an optical length between the light-emitting surface of the second red light-emitting layer and the light-reflective surface of the fourth one of the light-reflective electrodes is from 20 nm to 50 nm,
in the red sub-pixel region, an optical length between one of the light-emitting surfaces of the second blue light-emitting layer and the light-reflective surface of the first one of the light-reflective electrodes is from 210 nm to 230 nm,
in the green sub-pixel region, an optical length between one of the light-emitting surfaces of the second blue light-emitting layer and the light-reflective surface of the second one of the light-reflective electrodes is from 240 nm to 295 nm,
in the blue sub-pixel region, an optical length between one of the light-emitting surfaces of the second blue light-emitting layer and the light-reflective surface of the third one of the light-reflective electrodes is from 195 nm to 205 nm, and
in the white sub-pixel region, an optical length between one of the light-emitting surfaces of the second blue light-emitting layer and the light-reflective surface of the fourth one of the light-reflective electrodes is from 210 nm to 230 nm.
2. The organic EL display panel of claim 1 , wherein
in the white sub-pixel region, when light mixed from red light emitted from the second red light-emitting layer and blue light emitted from the second blue light-emitting layer is expressed in CIE chromaticity, an x value thereof is from 0.25 to 0.45, a y value thereof is from 0.25 to 0.45, and an absolute value of difference between the x value and the y value is from 0 to 0.05.
3. The organic EL display panel of claim 1 , wherein
the optical length between one of the light-emitting surfaces of the second blue light-emitting layer and the light-reflective surface of the first one of the light-reflective electrodes in the red sub-pixel region is different from the optical length between one of the light-emitting surfaces of the second blue light-emitting layer and the light-reflective surface of the fourth one of the light-reflective electrodes in the white sub-pixel region.
4. The organic EL display panel of claim 1 , wherein
the optical length between one of the light-emitting surfaces of the second blue light-emitting layer and the light-reflective surface of the first one of the light-reflective electrodes in the red sub-pixel region is the same as the optical length between one of the light-emitting surfaces of the second blue light-emitting layer and the light-reflective surface of the fourth one of the light-reflective electrodes in the white sub-pixel region.
5. The organic EL display panel of claim 1 , wherein
at least one of the first red light-emitting layer, the green light-emitting layer, the first blue light-emitting layer, and the second red light-emitting layer includes high-molecular material.
6. The organic EL display panel of claim 1 , wherein
the second blue light-emitting layer includes low-molecular material.
7. A display device comprising the organic EL display panel of claim 1 , and drive control circuitry that drives the organic EL display panel.
8. A method of manufacturing the organic EL display panel of claim 1 , the method comprising:
creating the first red light-emitting layer, the green light-emitting layer, the first blue light-emitting layer, and the second red light-emitting layer by using a wet process, and
creating the second blue light-emitting layer by using vacuum deposition or sputtering.
9. An organic electroluminescence (EL) display panel comprising:
a substrate;
a plurality of banks, disposed above the substrate, that define a red sub-pixel region, a green sub-pixel region, a blue sub-pixel region, and a white sub-pixel region;
a plurality of light-transmissive electrodes, disposed above the substrate in the red sub-pixel region, the green sub-pixel region, the blue sub-pixel region, and the white sub-pixel region;
a first red light-emitting unit disposed above a first one of the light-transmissive electrodes in the red sub-pixel region, the first red light-emitting unit including a first red light-emitting layer comprising a material that has an emission peak in a red wavelength region, the red light-emitting layer having a light-emitting surface that faces the first one of the light-transmissive electrodes;
a first green light-emitting unit disposed above a second one of the light-transmissive electrodes in the green sub-pixel region, the first green light-emitting unit including a green light-emitting layer comprising a material that has an emission peak in a green wavelength region, the green light-emitting layer having a light-emitting surface that faces the second one of the light-transmissive electrodes;
a first blue light-emitting unit disposed above a third one of the light-transmissive electrodes in the blue sub-pixel region, the first blue light-emitting unit including a first blue light-emitting layer comprising a material that has an emission peak in a blue wavelength region, the first blue light-emitting layer having a light-emitting surface that faces the third one of the light-transmissive electrodes;
a second red light-emitting unit disposed above a fourth one of the light-transmissive electrodes in the white sub-pixel region, the second red light-emitting unit including a second red light-emitting layer comprising a material that has an emission peak in a red wavelength region, the second red light-emitting layer having a light-emitting surface that faces the fourth one of the light-transmissive electrodes;
a charge generating layer disposed above the first red light-emitting unit, the first green light-emitting unit, the first blue light-emitting unit, and the second red light-emitting unit in the red sub-pixel region, the green sub-pixel region, the blue sub-pixel region, and the white sub-pixel region;
a second blue light-emitting unit disposed above the charge generating layer in the red sub-pixel region, the green sub-pixel region, the blue sub-pixel region, and the white sub-pixel region, the second blue light-emitting unit including a second blue light-emitting layer comprising a material that has an emission peak in a blue wavelength region, the second blue light-emitting layer having light-emitting surfaces that each face corresponding ones of the light-transmissive electrodes;
a light-reflective electrode disposed above the second blue light-emitting unit in the red sub-pixel region, the green sub-pixel region, the blue sub-pixel region, and the white sub-pixel region, the light-reflective electrode having a plurality of light-reflecting surfaces, and
a color filter layer that includes a red filter disposed below the first one of the light-transmissive electrodes in the red sub-pixel region, a green filter disposed below the second one of the light-transmissive electrodes in the green sub-pixel region, and a blue filter disposed below the third one of the light-transmissive electrodes in the blue sub-pixel region, wherein
in the red sub-pixel region, an optical length between the light-emitting surface of the first red light-emitting layer and a corresponding one of the light-reflective surfaces of the light-reflective electrode is from 255 nm to 300 nm,
in the green sub-pixel region, an optical length between the light-emitting surface of the green light-emitting layer and a corresponding one of the light-reflective surfaces of the light-reflective electrode is from 250 nm to 300 nm,
in the blue sub-pixel region, an optical length between the light-emitting surface of the first blue light-emitting layer and a corresponding one of the light-reflective surfaces of the light-reflective electrode is from 210 nm to 220 nm,
in the white sub-pixel region, an optical length between the light-emitting surface of the second red light-emitting layer and a corresponding one of the light-reflective surfaces of the light-reflective electrode is from 255 nm to 270 nm, and
in the red sub-pixel region, the green sub-pixel region, the blue sub-pixel region, and the white sub-pixel region, each optical length between the light-emitting surfaces of the second blue light-emitting layer and corresponding ones of the light-reflective surfaces of the light-reflective electrode is from 60 nm to 75 nm.
10. The organic EL display panel of claim 9 , wherein
in the white sub-pixel region, when light mixed from red light emitted from the second red light-emitting layer and blue light emitted from the second blue light-emitting layer is expressed in CIE chromaticity, an x value thereof is from 0.25 to 0.45, a y value thereof is from 0.25 to 0.45, and an absolute value of difference between the x value and the y value is from 0 to 0.05.
11. The organic EL display panel of claim 9 , wherein
the optical length between the light-emitting surface of the first red light-emitting layer and the corresponding one of the light-reflective surfaces of the light-reflective electrode in the red sub-pixel region is different from the optical length between the light-emitting surface of the second red light-emitting layer and the corresponding one of the light-reflective surfaces of the light-reflective electrode in the white sub-pixel region.
12. The organic EL display panel of claim 9 , wherein
the optical length between the light-emitting surface of the first red light-emitting layer and the corresponding one of the light-reflective surfaces of the light-reflective electrode in the red sub-pixel region is the same as the optical length between the light-emitting surface of the second red light-emitting layer and the corresponding one of the light-reflective surfaces of the light-reflective electrode in the white sub-pixel region.
13. The organic EL display panel of claim 9 , wherein
at least one of the first red light-emitting layer, the green light-emitting layer, the first blue light-emitting layer, and the second red light-emitting layer includes high-molecular material.
14. The organic EL display panel of claim 9 , wherein
the second blue light-emitting layer includes low-molecular material.