Light-emitting device and display device

Abstract

The embodiment of the invention discloses a light-emitting device and a display device, an optical modulation layer is arranged below an electron blocking layer corresponding to a blue light-emitting layer to increase the cavity length of a blue sub-pixel so as to enhance the forward light-emitting efficiency of the blue sub-pixel, and the forward light-emitting efficiency of the blue sub-pixel is improved through the cooperation of a light extraction layer and a first refractive index layer. The side view angle brightness attenuation corresponding to the blue sub-pixels can be reduced, so that the view angle color cast characteristic of red, green and blue mixed white light is improved, and the display effect is improved.

Description

Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a light-emitting device and a display apparatus. Background Art

[0002] A stacked OLED (Organic Electroluminescence Display) is a device that combines multiple light-emitting units connected in series via a charge-generating layer and is controlled by a single external power source. Compared to single-layer OLEDs, stacked OLEDs offer higher brightness and current efficiency at the same voltage. These brightness and current efficiency increase exponentially with the number of light-emitting units connected in series. Furthermore, stacked OLEDs also offer a longer lifespan at the same current density than single-layer OLEDs.

[0003] However, although stacked OLED devices with a strong microcavity effect have high efficiency, narrow spectrum, and high color gamut, their enhanced wavelength positions are more concentrated, so they are disadvantageous in terms of viewing angle. Since the cavity length of the tandem device is longer and the half-height width is narrower, the number of wavelengths that can compensate for each other after the viewing angle is changed is smaller, so the viewing angle brightness attenuation ratio is larger, and the efficiency of blue light is the most sensitive to changes in white light efficiency. That is to say, when the R / G / B luminous efficiency changes by the same proportion, the change in blue light efficiency brings more changes in white light efficiency. When the blue light viewing angle characteristics are poor, the mixed white visual color polarization characteristics are poor. Therefore, how to design the blue light device structure in the stacked OLED device to improve the visual color polarization characteristics of the tandem device is very urgent. Summary of the Invention

[0004] The embodiments of the present disclosure provide a light-emitting device and a display apparatus for improving the color deviation characteristics of the viewing angle and enhancing the display effect.

[0005] In one aspect, an embodiment of the present disclosure provides a light-emitting device, comprising: an anode and a cathode disposed opposite to each other, at least two light-emitting units stacked between the anode and the cathode, a charge generation unit disposed between two adjacent light-emitting units, a light extraction layer disposed on a side of the cathode away from the anode, and a first refractive index layer disposed on a side of the light extraction layer away from the anode;

[0006] Among them, each of the light-emitting units includes an electron blocking layer and a light-emitting layer arranged in a stacked manner, the electron blocking layer is close to the anode, and the light-emitting layer includes a red light-emitting layer, a green light-emitting layer and a blue light-emitting layer whose orthographic projections on the anode do not overlap, and at least one of the light-emitting units is provided with an optical modulation layer on the side of its electron blocking layer close to the anode and corresponding to its blue light-emitting layer area.

[0007] In a possible implementation, in the above-mentioned light-emitting device provided in the embodiment of the present disclosure, in the light-emitting unit provided with the optical modulation layer, the vertical spacing between the blue light-emitting layer and the red light-emitting layer is 80 to 120 nm.

[0008] In a possible implementation, in the above-mentioned light-emitting device provided in the embodiment of the present disclosure, the refractive index of the light extraction layer is 1.8 to 2.3, and the refractive index of the first refractive index layer is 1.8 to 2.2.

[0009] In a possible implementation, the above-mentioned light-emitting device provided in the embodiment of the present disclosure further includes a second refractive index layer arranged between the light extraction layer and the first refractive index layer, the orthographic projection of the second refractive index layer on the anode does not overlap with the orthographic projection of the blue light-emitting layer on the anode, and the refractive index of the second refractive index layer is 1.4 to 1.6.

[0010] In a possible implementation, the light emitting device provided in the embodiment of the present disclosure further includes a second refractive index layer disposed between the light extraction layer and the first refractive index layer, wherein the refractive index of the second refractive index layer is 1.4 to 1.6;

[0011] The light extraction layer includes a first light extraction layer and a second light extraction layer that are in the same layer and spaced apart. The orthographic projection of the first light extraction layer on the anode covers the orthographic projection of the red light-emitting layer and the green light-emitting layer on the anode. The orthographic projection of the second light extraction layer on the anode covers the orthographic projection of the blue light-emitting layer on the anode. The thickness of the second light extraction layer is greater than the thickness of the first light extraction layer.

[0012] In a possible implementation, in the above-mentioned light-emitting device provided in an embodiment of the present disclosure, the light extraction layer includes a first light extraction layer and a second light extraction layer that are arranged in the same layer and spaced apart from each other, the orthographic projection of the first light extraction layer on the anode covers the orthographic projections of the red light-emitting layer and the green light-emitting layer on the anode, the orthographic projection of the second light extraction layer on the anode covers the orthographic projection of the blue light-emitting layer on the anode, and the thickness of the second light extraction layer is greater than that of the first light extraction layer;

[0013] It also includes a second refractive index layer arranged between the first light extraction layer and the first refractive index layer, the orthographic projection of the second refractive index layer on the anode covers the orthographic projections of the red light-emitting layer and the green light-emitting layer on the anode, and the refractive index of the second refractive index layer is 1.4 to 1.6.

[0014] In a possible implementation, in the above-mentioned light-emitting device provided in an embodiment of the present disclosure, the light-emitting unit provided with the optical modulation layer is located between the anode and the charge generating unit, the electron blocking layer in the light-emitting unit provided with the optical modulation layer is a first electron blocking layer, and the light-emitting layer is a first light-emitting layer.

[0015] In a possible implementation, in the above-mentioned light-emitting device provided in an embodiment of the present disclosure, the light-emitting unit provided with the optical modulation layer further includes: a hole injection layer located between the anode and the first electron blocking layer, a first hole transport layer located between the hole injection layer and the first electron blocking layer, a first hole blocking layer located between the first light-emitting layer and the charge generating unit, and a first electron transport layer located between the first hole blocking layer and the charge generating unit;

[0016] Wherein, the optical modulation layer and the first hole transport layer are an integrated structure.

[0017] In one possible implementation, in the above-mentioned light-emitting device provided in the embodiment of the present disclosure, the light-emitting unit located between the cathode and the charge generating unit includes: an electron injection layer located between the cathode and the charge generating unit, a second electron transport layer located between the electron injection layer and the charge generating unit, a second hole blocking layer located between the second electron transport layer and the charge generating unit, a second light-emitting layer located between the second hole blocking layer and the charge generating unit, a second electron blocking layer located between the second light-emitting layer and the charge generating unit, and a second hole transport layer located between the second electron blocking layer and the charge generating unit.

[0018] On the other hand, an embodiment of the present disclosure further provides a display device, comprising the above-mentioned light-emitting device provided by an embodiment of the present disclosure.

[0019] The beneficial effects of the embodiments of the present disclosure are as follows:

[0020] The embodiments of the present disclosure provide a light-emitting device and a display apparatus. An optical modulation layer is provided below the electron blocking layer corresponding to the blue light-emitting layer to increase the cavity length of the blue sub-pixel, thereby enhancing the forward light extraction efficiency of the blue sub-pixel. Furthermore, through the cooperation of the light extraction layer and the first refractive index layer, the brightness attenuation corresponding to the blue sub-pixel at a side viewing angle can be reduced, thereby improving the visual color chromatic aberration characteristics of the red, green, and blue mixed white light and enhancing the display effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic structural diagram of a light-emitting device provided in an embodiment of the present disclosure;

[0022] Figure 2A schematic structural diagram of another light-emitting device provided in an embodiment of the present disclosure;

[0023] Figure 3 A schematic structural diagram of another light-emitting device provided in an embodiment of the present disclosure;

[0024] Figure 4 A schematic structural diagram of another light-emitting device provided in an embodiment of the present disclosure;

[0025] Figure 5 for Figure 1-Figure 4 Schematic diagram of the luminous mixed white color corresponding to the structure shown. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. And in the absence of conflict, the embodiments in the present disclosure and the features in the embodiments can be combined with each other. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0027] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the usual meanings understood by persons of ordinary skill in the field to which this disclosure belongs. The words “include” or “comprise” and the like used in this disclosure mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. The words “connect” or “connected” and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Inside”, “outside”, “upper”, “lower”, etc. are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0028] It should be noted that the sizes and shapes of the figures in the accompanying drawings do not reflect the actual scale and are only for the purpose of illustrating the present disclosure. The same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions.

[0029] The present disclosure provides a light emitting device, such as Figure 1-Figure 4As shown, the light emitting device comprises: an anode 1 (Anode) and a cathode 2 (Cathode) arranged opposite to each other, at least two light emitting units 3 stacked between the anode 1 and the cathode 2, a charge generating unit 4 arranged between two adjacent light emitting units 3, a light extraction layer 5 (CPL) arranged on the side of the cathode 2 away from the anode 1, and a first refractive index layer 6 arranged on the side of the light extraction layer 5 away from the anode 1. The embodiment of the present disclosure is described by taking the light emitting device including two light emitting units 3 as an example;

[0030] Among them, each light-emitting unit 3 includes an electron blocking layer EBL and a light-emitting layer EML arranged in a stacked manner, the electron blocking layer EBL is close to the anode 1, and the light-emitting layer EML includes a red light-emitting layer R-EML, a green light-emitting layer G-EML and a blue light-emitting layer B-EML whose orthographic projections on the anode 1 do not overlap, and at least one light-emitting unit 3 is provided with an optical modulation layer 7 on the side of its electron blocking layer EBL close to the anode 1 and corresponding to its blue light-emitting layer B-EML area.

[0031] The above-mentioned light-emitting device provided in the embodiment of the present disclosure increases the cavity length of the blue sub-pixel by arranging an optical modulation layer below the electron blocking layer corresponding to the blue light-emitting layer, thereby enhancing the forward light extraction efficiency of the blue sub-pixel, and through the cooperation of the light extraction layer and the first refractive index layer, the side viewing angle brightness attenuation corresponding to the blue sub-pixel can be reduced, thereby improving the visual color chromatic aberration characteristics of the red, green and blue mixed white light and improving the display effect.

[0032] In some embodiments, in the above-mentioned light-emitting device provided in the embodiments of the present disclosure, as Figure 1-Figure 4 As shown, the light-emitting unit 3 provided with the optical modulation layer 7 can be located between the anode 1 and the charge generation unit 4. That is, the light-emitting unit 3 provided with the optical modulation layer 7 is closest to the anode 1. This light-emitting unit 3 is referred to as the first light-emitting unit 3'. The electron blocking layer EBL in the first light-emitting unit 3' is the first electron blocking layer 31 (EBL-1), the light-emitting layer EML is the first light-emitting layer 32, and the blue light-emitting layer B-EML is the first blue light-emitting layer B-EML-1. In this way, by providing the optical modulation layer 7 below the first electron blocking layer 31 (EBL-1) corresponding to the first blue light-emitting layer B-EML-1 of the first light-emitting unit 3', the color shift characteristics of the viewing angle are improved.

[0033] In some embodiments, in the above-mentioned light-emitting device provided in the embodiments of the present disclosure, as Figure 1-Figure 4As shown, the light-emitting unit 3 (i.e., the first light-emitting unit 3') provided with the optical modulation layer 7 further includes: a hole injection layer 33 (HIL) located between the anode 1 and the first electron blocking layer 31, a first hole transport layer 34 (HTL-1) located between the hole injection layer 33 and the first electron blocking layer 31, a first hole blocking layer 35 (HBL-1) located between the first light-emitting layer 32 and the charge generation unit 4, and a first electron transport layer 36 (ETL1) located between the first hole blocking layer 35 and the charge generation unit 4;

[0034] The optical modulation layer 7 and the first hole transport layer 34 are integrally formed. This allows the first hole transport layer 34 to be thickened in the region corresponding to the first blue light-emitting layer B-EML-1 to form the optical modulation layer 7. The thickness of the optical modulation layer 7 can be adjusted as needed, eliminating the need for a separate process for producing the optical modulation layer 7, saving on masks and reducing costs.

[0035] In some embodiments, the optical modulation layer 7 may also be other hole transport materials, that is, the optical modulation layer 7 and the first hole transport layer 34 may be two independent film layers.

[0036] In some embodiments, in the above-mentioned light-emitting device provided in the embodiments of the present disclosure, as Figure 1-Figure 4 As shown, the light-emitting unit 3 located between the cathode 2 and the charge generation unit 4 (referred to as the second light-emitting unit 3") includes: an electron injection layer 37 (EIL) located between the cathode 2 and the charge generation unit 4, a second electron transport layer 38 (ETL-2) located between the electron injection layer 37 and the charge generation unit 4, a second hole blocking layer 39 (HBL-2) located between the second electron transport layer 38 and the charge generation unit 4, a second light-emitting layer 310 located between the second hole blocking layer 39 and the charge generation unit 4, a second electron blocking layer 311 (EBL-2) located between the second light-emitting layer 310 and the charge generation unit 4, and a second hole transport layer 312 (HTL-2) located between the second electron blocking layer 311 and the charge generation unit 4.

[0037] In some embodiments, in the above-mentioned light-emitting device provided in the embodiments of the present disclosure, as Figure 1-Figure 4 As shown, the first light-emitting layer 32 may include a first red light-emitting layer R-EML-1, a first green light-emitting layer G-EML-1 and a first blue light-emitting layer B-EML-1, and the second light-emitting layer 310 may include a second red light-emitting layer R-EML-2, a second green light-emitting layer G-EML-2 and a second blue light-emitting layer B-EML-2.

[0038] In some embodiments, in the above-mentioned light-emitting device provided in the embodiments of the present disclosure, as Figure 1-Figure 4As shown, the thickness of the first electron blocking layer 31 (R-EBL-1) below the first red light-emitting layer R-EML-1, the thickness of the first electron blocking layer 31 (G-EBL-1) below the first green light-emitting layer G-EML-1, and the thickness of the first electron blocking layer 31 (B-EBL-1) below the first blue light-emitting layer B-EML-1 decrease in sequence. The first electron blocking layer 31 (R-EBL-1) below the first red light-emitting layer R-EML-1 is set to be thicker than the first electron blocking layer 31 corresponding to other color light-emitting layers, which is beneficial to enhancing the microcavity effect and improving the light extraction efficiency.

[0039] In some embodiments, in the above-mentioned light-emitting device provided in the embodiments of the present disclosure, as Figure 1-Figure 4 As shown, the thickness of the second electron blocking layer 311 (R-EBL-2) below the second red light-emitting layer R-EML-2, the thickness of the second electron blocking layer 311 (G-EBL-2) below the second green light-emitting layer G-EML-2, and the thickness of the second electron blocking layer 311 (B-EBL-2) below the second blue light-emitting layer B-EML-2 decrease in sequence. The second electron blocking layer 311 (R-EBL-2) below the second red light-emitting layer R-EML-2 is set to be thicker than the second electron blocking layer 311 corresponding to other color light-emitting layers, which is beneficial to enhancing the microcavity effect and improving the light extraction efficiency.

[0040] In some embodiments, in the above-mentioned light-emitting device provided in the embodiments of the present disclosure, as Figure 1-Figure 4 As shown, the charge generation unit 4 includes an N-type charge generation layer N-CGL and a P-type charge generation layer P-CGL. The N-type charge generation layer N-CGL is also an N-type organic semiconductor, and the P-type charge generation layer P-CGL is also a P-type organic semiconductor.

[0041] In some embodiments, in the above-mentioned light-emitting device provided in the embodiments of the present disclosure, as Figure 1-Figure 4 As shown, the structure further includes an inorganic layer 8 (CVD) located on the side of the first refractive index layer 6 away from the anode 1 .

[0042] The following is a detailed introduction to the recombination of electrons and holes in the light-emitting layer:

[0043] The electrons generated at the interface between the N-type charge generation layer N-CGL and the P-type charge generation layer P-CGL are transferred to the first light-emitting layer 32. Specifically, electrons and holes are generated at the interface between the N-type charge generation layer N-CGL and the P-type charge generation layer P-CGL. The N-type charge generation layer N-CGL and the P-type charge generation layer P-CGL work together to separate the electrons and holes. The N-type charge generation layer N-CGL obtains electrons and injects them into the first electron transport layer 36. The first electron transport layer 36 transfers the electrons to the first hole blocking layer 35. The first hole blocking layer 35 is configured to block holes and transfer the received electrons to the first light-emitting layer 32.

[0044] The holes generated by the anode 1 are transferred to the first light-emitting layer 32. Specifically, the hole injection layer 33 injects the holes generated by the anode 1 into the first hole transport layer 34. The first hole transport layer 34 transfers the holes to the first electron blocking layer 31. The first electron blocking layer 31 is configured to block electrons and transfer the received holes to the first light-emitting layer 32.

[0045] The holes generated at the interface between the N-type charge generation layer N-CGL and the P-type charge generation layer P-CGL are transferred to the second light-emitting layer 310. Specifically, the N-type charge generation layer N-CGL and the P-type charge generation layer P-CGL work together to separate electrons and holes, wherein the P-type charge generation layer P-CGL acquires holes and injects them into the second hole transport layer 312. The second hole transport layer 312 transfers the holes to the second electron blocking layer 311. The second electron blocking layer 311 is configured to block electrons and transfer the received holes to the second light-emitting layer 310.

[0046] The electrons generated by the cathode 2 are transferred to the second light-emitting layer 310. Specifically, the electron injection layer 37 injects the electrons generated by the cathode 2 into the second electron transport layer 38. The second electron transport layer 38 transfers the electrons to the second hole blocking layer 38. The second hole blocking layer 38 is configured to block holes and transfer the received electrons to the second light-emitting layer 310.

[0047] In some embodiments, in the above-mentioned light-emitting device provided in the embodiments of the present disclosure, as Figure 1-Figure 4As shown, in the light-emitting unit 3 (i.e., the first light-emitting unit 3') provided with an optical modulation layer 7, the vertical spacing between the blue light-emitting layer (i.e., the first blue light-emitting layer B-EML-1) and the red light-emitting layer (i.e., the first red light-emitting layer R-EML-1) is 80 to 120 nm. The optical modulation layer 7 is thus used to adjust the height of the first blue light-emitting layer B-EML-1 relative to the first red light-emitting layer R-EML-1, thereby enhancing the forward light extraction efficiency of the blue sub-pixel. Furthermore, the light extraction layer 5 and the first refractive index layer 6 cooperate to reduce the side-view brightness attenuation of the blue sub-pixel, thereby improving the color chromatic aberration of the red, green, and blue mixed white light and enhancing the display effect.

[0048] In some embodiments, in the above-mentioned light-emitting device provided in the embodiments of the present disclosure, as Figure 1-Figure 4 As shown, the refractive index of light extraction layer 5 is 1.8 to 2.3, and the refractive index n of first refractive index layer 6 is 1.8 to 2.2, meaning that first refractive index layer 6 is a high refractive index layer (High n layer). The combination of light extraction layer 5 and the high refractive index first refractive index layer 6 improves the visual color shift of red, green, and blue mixed white light, enhancing the display effect.

[0049] In some embodiments, in the above-mentioned light-emitting device provided in the embodiments of the present disclosure, as Figure 2 As shown, it also includes a second refractive index layer 9 arranged between the light extraction layer 5 and the first refractive index layer 6. The orthographic projection of the second refractive index layer 9 on the anode 1 does not overlap with the orthographic projection of the blue light-emitting layer (i.e., the first blue light-emitting layer B-EML-1) on the anode 1. The refractive index of the second refractive index layer 9 is 1.4-1.6, that is, the second refractive index layer 9 is a low refractive index layer (Low n layer). In this way, through the cooperation of the light extraction layer 5, the low refractive index second refractive index layer 9 and the high refractive index first refractive index layer 6, the visual color polarization characteristics of the red, green and blue mixed white light can be further improved, thereby improving the display effect.

[0050] In some embodiments, in the above-mentioned light-emitting device provided in the embodiments of the present disclosure, as Figure 3 As shown, it further includes a second refractive index layer 9 disposed between the light extraction layer 5 and the first refractive index layer 6, and the refractive index of the second refractive index layer 9 is 1.4 to 1.6;

[0051] The light extraction layer 5 includes a first light extraction layer CPL1 and a second light extraction layer CPL2 arranged in the same layer and spaced apart. The orthographic projection of the first light extraction layer CPL1 on the anode 1 overlaps the orthographic projections of the red light-emitting layer R-EML and the green light-emitting layer G-EML on the anode 1. The orthographic projection of the second light extraction layer CPL2 on the anode 1 overlaps the orthographic projection of the blue light-emitting layer B-EML on the anode 1. The thickness of the second light extraction layer CPL2 is greater than that of the first light extraction layer CPL1. Thus, through the coordination of the light extraction layer 5, the low-refractive-index second refractive-index layer 9, and the high-refractive-index first refractive-index layer 6, and by setting the thickness of the second light extraction layer CPL2 corresponding to the blue light-emitting layer B-EML to be greater than the thickness of the first light extraction layer CPL1 corresponding to the red-light-emitting layer R-EML and the green-light-emitting layer G-EML, the visual color chromatic aberration characteristics of the red, green, and blue mixed white light can be further improved, thereby enhancing the display effect.

[0052] In some embodiments, in the above-mentioned light-emitting device provided in the embodiments of the present disclosure, as Figure 4 As shown, the light extraction layer 5 includes a first light extraction layer CPL1 and a second light extraction layer CPL2 that are arranged in the same layer and spaced apart. The orthographic projection of the first light extraction layer CPL1 on the anode 1 covers the orthographic projections of the red light-emitting layer R-EML and the green light-emitting layer G-EML on the anode 1. The orthographic projection of the second light extraction layer CPL2 on the anode 1 covers the orthographic projection of the blue light-emitting layer B-EML on the anode 1. The thickness of the second light extraction layer CPL2 is greater than that of the first light extraction layer CPL1.

[0053] The display further includes a second refractive index layer 9 disposed between the first light extraction layer CPL1 and the first refractive index layer 6. The orthographic projection of the second refractive index layer 9 on the anode 1 overlaps the orthographic projections of the red light-emitting layer R-EML and the green light-emitting layer G-EML on the anode 1. The refractive index of the second refractive index layer 9 is 1.4 to 1.6. By combining the light extraction layer 5, the low-refractive-index second refractive index layer 9, and the high-refractive-index first refractive index layer 6, and by setting the thickness of the second light extraction layer CPL2 corresponding to the blue light-emitting layer B-EML to be greater than the thickness of the first light extraction layer CPL1 corresponding to the red light-emitting layer R-EML and the green light-emitting layer G-EML, and by providing the low-refractive-index second refractive index layer 9 only in the red light-emitting layer R-EML and green light-emitting layer G-EML regions, the visual color chromatic aberration characteristics of the red, green, and blue mixed white light can be further improved, thereby enhancing the display effect.

[0054] like Figure 5 As shown, Figure 5 for Figure 1-Figure 4 The structure shown corresponds to the luminous mixed white bias diagram, and it can be seen that Figure 1-Figure 4 The color deviations of the structures shown are all within the spec range, where Figure 3 and Figure 4The structure shown is more effective in improving the color shift characteristics.

[0055] Based on the same inventive concept, embodiments of the present disclosure further provide a display device comprising the aforementioned light-emitting device provided in the embodiments of the present disclosure. The display device can be any product or component with a display function, such as a mobile phone, tablet computer, television, monitor, laptop computer, digital photo frame, or navigation system. The implementation of the display device can be referenced to the aforementioned light-emitting device embodiments, and any repetitive details will not be repeated here.

[0056] The above-mentioned light-emitting device and display device provided by the embodiments of the present disclosure increase the cavity length of the blue sub-pixel by arranging an optical modulation layer below the electron blocking layer corresponding to the blue light-emitting layer, thereby enhancing the forward light extraction efficiency of the blue sub-pixel, and through the cooperation of the light extraction layer and the first refractive index layer, the side viewing angle brightness attenuation corresponding to the blue sub-pixel can be reduced, thereby improving the visual color chromatic aberration characteristics of the red, green and blue mixed white light and improving the display effect.

[0057] Although the preferred embodiments of the present disclosure have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present disclosure.

[0058] Obviously, those skilled in the art may make various changes and modifications to the embodiments of the present disclosure without departing from the spirit and scope of the embodiments of the present disclosure. Thus, if such changes and modifications of the embodiments of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is intended to include such changes and modifications.

Claims

1. A light emitting device, characterized in that: include: An anode and a cathode disposed opposite to each other, at least two light-emitting units stacked between the anode and the cathode, a charge generation unit disposed between two adjacent light-emitting units, a light extraction layer disposed on a side of the cathode away from the anode, and a first refractive index layer disposed on a side of the light extraction layer away from the anode; Among them, each of the light-emitting units includes an electron blocking layer and a light-emitting layer arranged in a stacked manner, the electron blocking layer is close to the anode, and the light-emitting layer includes a red light-emitting layer, a green light-emitting layer and a blue light-emitting layer whose orthographic projections on the anode do not overlap, and at least one of the light-emitting units is provided with an optical modulation layer on the side of its electron blocking layer close to the anode and corresponding to its blue light-emitting layer area.

2. The light emitting device according to claim 1, wherein In the light-emitting unit provided with the optical modulation layer, a vertical distance between the blue light-emitting layer and the red light-emitting layer is 80 to 120 nm.

3. The light emitting device according to claim 1, wherein The refractive index of the light extraction layer is 1.8 to 2.3, and the refractive index of the first refractive index layer is 1.8 to 2.

2.

4. The light emitting device according to any one of claims 1 to 3, characterized in that: It also includes a second refractive index layer arranged between the light extraction layer and the first refractive index layer, the orthographic projection of the second refractive index layer on the anode does not overlap with the orthographic projection of the blue light-emitting layer on the anode, and the refractive index of the second refractive index layer is 1.4 to 1.

6.

5. The light emitting device according to any one of claims 1 to 3, characterized in that: Also included is a second refractive index layer disposed between the light extraction layer and the first refractive index layer, wherein the refractive index of the second refractive index layer is 1.4 to 1.6; The light extraction layer includes a first light extraction layer and a second light extraction layer that are in the same layer and spaced apart. The orthographic projection of the first light extraction layer on the anode covers the orthographic projection of the red light-emitting layer and the green light-emitting layer on the anode. The orthographic projection of the second light extraction layer on the anode covers the orthographic projection of the blue light-emitting layer on the anode. The thickness of the second light extraction layer is greater than the thickness of the first light extraction layer.

6. The light emitting device according to any one of claims 1 to 3, characterized in that: The light extraction layer includes a first light extraction layer and a second light extraction layer that are arranged in the same layer and spaced apart. The orthographic projection of the first light extraction layer on the anode covers the orthographic projections of the red light-emitting layer and the green light-emitting layer on the anode. The orthographic projection of the second light extraction layer on the anode covers the orthographic projection of the blue light-emitting layer on the anode. The thickness of the second light extraction layer is greater than that of the first light extraction layer. It also includes a second refractive index layer arranged between the first light extraction layer and the first refractive index layer, the orthographic projection of the second refractive index layer on the anode covers the orthographic projections of the red light-emitting layer and the green light-emitting layer on the anode, and the refractive index of the second refractive index layer is 1.4 to 1.

6.

7. The light emitting device according to claim 1, wherein The light-emitting unit provided with the optical modulation layer is located between the anode and the charge generation unit. The electron blocking layer in the light-emitting unit provided with the optical modulation layer is a first electron blocking layer, and the light-emitting layer is a first light-emitting layer.

8. The light emitting device according to claim 7, wherein: The light-emitting unit provided with the optical modulation layer further includes: a hole injection layer located between the anode and the first electron blocking layer, a first hole transport layer located between the hole injection layer and the first electron blocking layer, a first hole blocking layer located between the first light-emitting layer and the charge generating unit, and a first electron transport layer located between the first hole blocking layer and the charge generating unit; Wherein, the optical modulation layer and the first hole transport layer are an integrated structure.

9. The light emitting device according to claim 7, wherein: The light-emitting unit located between the cathode and the charge generating unit includes: an electron injection layer located between the cathode and the charge generating unit, a second electron transport layer located between the electron injection layer and the charge generating unit, a second hole blocking layer located between the second electron transport layer and the charge generating unit, a second light-emitting layer located between the second hole blocking layer and the charge generating unit, a second electron blocking layer located between the second light-emitting layer and the charge generating unit, and a second hole transport layer located between the second electron blocking layer and the charge generating unit.

10. A display device, characterized in that: The light emitting device comprises the light emitting device according to any one of claims 1 to 9.

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