Organic electroluminescence device, display panel, and driving method

Abstract

The application relates to an organic electroluminescence device, a display panel and a driving method, the organic electroluminescence device sets light-emitting materials in a first light-emitting layer, a second light-emitting layer and a third light-emitting layer respectively, the first light-emitting layer and the second light-emitting layer are arranged in a laminated mode in a first region of a pixel unit, the third light-emitting layer is arranged in a second region which is parallel to the first region, and a first functional layer is arranged to penetrate the second light-emitting layer; the first light-emitting layer or the second light-emitting layer can be controlled to emit light according to the size of the voltage acting on the first functional layer; since the first light-emitting layer and the second light-emitting layer are arranged in the same region of the pixel unit, the effective pixel density in a unit area can be greatly improved, and therefore the display resolution can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to an organic electroluminescent device, a display panel and a driving method. BACKGROUND

[0002] At present, organic light emitting diodes (OLED) are widely used in the field of display technology. In the organic electroluminescent device of the OLED display panel, red light emitting materials, green light emitting materials and blue light emitting materials are arranged, and through the combination of different intensities or brightnesses of the three colors, color display can be realized. OLEDs need at least three primary color sub-pixels to form an effective pixel for color display, but at present, the three color light emitting materials are arranged in a light emitting layer of the organic electroluminescent device, which results in a low density of the organic electroluminescent device in a unit area and a low display resolution. SUMMARY

[0003] The present application provides an organic electroluminescent device, a display panel and a driving method to solve the technical problem of how to improve the effective pixel density of OLED in a unit area to improve the display resolution.

[0004] In a first aspect, the present application provides an organic electroluminescent device, comprising: a substrate, a cathode layer, a hole blocking layer, a first functional layer, a light emitting layer and an anode layer.

[0005] The cathode layer is arranged on the substrate, the anode layer is arranged on the cathode layer, and the hole blocking layer and the light emitting layer are arranged in a stack between the cathode layer and the anode layer.

[0006] The light emitting layer comprises a plurality of pixel units; each pixel unit comprises a first light emitting layer, a second light emitting layer and a third light emitting layer; the first light emitting layer, the second light emitting layer and the third light emitting layer correspond to light emitting materials of different colors respectively; the first light emitting layer and the second light emitting layer are arranged in a stack in a first area of the pixel unit, the third light emitting layer is arranged in a second area of the pixel unit, and the first area and the second area are arranged side by side.

[0007] The first functional layer is arranged between the first light emitting layer and the cathode layer, the first functional layer penetrates the second light emitting layer, and the hole blocking layer wraps the first functional layer.

[0008] The first light-emitting layer emits light when a voltage acting on the first functional layer is greater than or equal to a critical voltage of the first functional layer; and the second light-emitting layer emits light when the voltage acting on the first functional layer is less than the critical voltage of the first functional layer.

[0009] Optionally, the organic electroluminescent device further comprises a second functional layer; and the third light-emitting layer comprises an upper light-emitting layer and a lower light-emitting layer.

[0010] The second functional layer is arranged between the upper light-emitting layer and the cathode layer, the second functional layer penetrates through the lower light-emitting layer, and the hole blocking layer wraps the second functional layer.

[0011] The upper light-emitting layer emits light when a voltage acting on the second functional layer is greater than or equal to a critical voltage of the second functional layer; and the lower light-emitting layer emits light when the voltage acting on the second functional layer is less than the critical voltage of the second functional layer.

[0012] Optionally, the organic electroluminescent device further comprises a hole injection layer, a hole transport layer, an electron blocking layer, an electron transport layer and an electron injection layer.

[0013] The electron blocking layer is arranged between the anode layer and the first light-emitting layer and the third light-emitting layer close to the anode layer, the hole transport layer is arranged between the anode layer and the electron blocking layer, and the hole injection layer is arranged between the anode layer and the hole transport layer.

[0014] The electron transport layer is arranged between the cathode layer and the hole blocking layer, and the electron injection layer is arranged between the cathode layer and the electron transport layer.

[0015] Optionally, the first functional layer is composed of a piezoresistor or a Zener thin-film diode; and the second functional layer is composed of a piezoresistor or a Zener thin-film diode.

[0016] Optionally, the critical voltage of the first functional layer and the critical voltage of the second functional layer are adjusted by the thickness of the piezoresistor, or adjusted by the doping of the piezoresistor, or adjusted by the thin-film material of the Zener thin-film diode, or adjusted by the thin-film doping.

[0017] Optionally, the organic electroluminescent device further comprises a quarter-wave plate and a polaroid.

[0018] The polaroid is arranged on the outside of the substrate, and the quarter-wave plate is arranged between the substrate and the polaroid.

[0019] Optionally, the substrate, the cathode layer and the anode layer are all transparent materials.

[0020] Optionally, the light-emitting layer comprises a red light-emitting material, a green light-emitting material and a blue light-emitting material.

[0021] The first light-emitting layer is a first one of the red light-emitting material, the green light-emitting material and the blue light-emitting material.

[0022] The second light-emitting layer is a second one of the red light-emitting material, the green light-emitting material and the blue light-emitting material.

[0023] The third light-emitting layer is a third one of the red light-emitting material, the green light-emitting material and the blue light-emitting material.

[0024] In a second aspect, the present application provides a display panel, comprising the organic electroluminescent device of any one of the first aspect.

[0025] In a third aspect, the present application provides a method for driving an organic electroluminescent device, applied to the display panel of the second aspect, and the method comprises:

[0026] determining a voltage acting on the first functional layer according to a color to be displayed by the organic electroluminescent device in the display panel;

[0027] when the voltage acting on the first functional layer is greater than or equal to a threshold voltage of the first functional layer, the first light-emitting layer emits light;

[0028] when the voltage acting on the first functional layer is less than the threshold voltage of the first functional layer, the second light-emitting layer emits light.

[0029] Compared with the prior art, the technical scheme provided by the embodiment of the present application has the following advantages: the organic electroluminescent device provided by the embodiment of the present application comprises a substrate, a cathode layer, a hole blocking layer, a first functional layer, a light-emitting layer and an anode layer; the cathode layer is arranged on the substrate, the anode layer is arranged on the cathode layer, and the hole blocking layer and the light-emitting layer are arranged in a stack between the cathode layer and the anode layer; wherein the light-emitting layer comprises a plurality of pixel units; each pixel unit comprises a first light-emitting layer, a second light-emitting layer and a third light-emitting layer; the first light-emitting layer, the second light-emitting layer and the third light-emitting layer correspond to light-emitting materials of different colors respectively; the first light-emitting layer and the second light-emitting layer are arranged in a stack in a first region of the pixel unit, the third light-emitting layer is arranged in a second region of the pixel unit, and the first region and the second region are arranged side by side; the first functional layer is arranged between the first light-emitting layer and the cathode layer, the first functional layer penetrates through the second light-emitting layer, and the hole blocking layer wraps the first functional layer; when the voltage acting on the first functional layer is greater than or equal to the critical voltage of the first functional layer, the first light-emitting layer emits light; when the voltage acting on the first functional layer is less than the critical voltage of the first functional layer, the second light-emitting layer emits light. The organic electroluminescent device sets the light-emitting materials in the first light-emitting layer, the second light-emitting layer and the third light-emitting layer respectively, the first light-emitting layer and the second light-emitting layer are arranged in a stack in the first region of the pixel unit, the third light-emitting layer is arranged in the second region which is arranged side by side with the first region, and the first functional layer penetrates through the second light-emitting layer, so that the first light-emitting layer or the second light-emitting layer can be controlled to emit light according to the size of the voltage acting on the first functional layer. Since the first light-emitting layer and the second light-emitting layer are arranged in the same region of the pixel unit, the effective pixel density in a unit area can be greatly improved, and thus the display resolution can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0030] The drawings herein are incorporated into the specification and form a part of the specification, show embodiments consistent with the present application, and together with the specification serve to explain the principles of the present application.

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, for those skilled in the art, other drawings can also be obtained from these drawings without any creative labor.

[0032] One or more embodiments are exemplarily illustrated by pictures in the drawings corresponding thereto, and these exemplary illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, unless otherwise specified. The drawings in the drawings do not constitute a proportional limitation.

[0033] Figure 1 FIG. 1 is a schematic diagram of an OLED display principle;

[0034] Figure 2 FIG. 2 is a schematic diagram of an OLED display panel structure;

[0035] Figure 3 FIG. 3 is a schematic diagram of a structure of an organic electroluminescent device provided in an embodiment of the present application;

[0036] Figure 4 FIG. 4 is a schematic diagram of a circuit principle of an organic electroluminescent device provided in an embodiment of the present application;

[0037] Figure 5 FIG. 5 is a schematic diagram of a structure of an organic electroluminescent device provided in another embodiment of the present application;

[0038] Figure 6 FIG. 6 is a schematic diagram of a structure of a bidirectional light-emitting organic electroluminescent device provided in an embodiment of the present application;

[0039] Figure 7 FIG. 7 is a schematic diagram of green light excitation provided in an embodiment of the present application;

[0040] Figure 8 FIG. 8 is a schematic diagram of red light excitation provided in an embodiment of the present application;

[0041] Figure 9 FIG. 9 is a flowchart of a driving method of an organic electroluminescent device provided in an embodiment of the present application.

[0042] The reference signs are as follows:

[0043] 1-organic electroluminescent device; 11-substrate; 12-anode layer; 13-cathode layer; 14-polarizer; 15-quarter wave plate; 16-encapsulation layer; 21-red light-emitting material; 22-green light-emitting material; 23-blue light-emitting material; 31-first functional layer; 32-second functional layer. DETAILED DESCRIPTION

[0044] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in connection with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0045] The following disclosure provides a number of different embodiments or examples for implementing the different structures of the present application. In order to simplify the disclosure of the present application, the components and arrangements of specific examples are described below. Of course, they are merely examples and the purpose is not to limit the present application. In addition, reference numerals and / or letters can be repeated in different examples of the present application. Such repetition is for the purpose of simplification and clarity, and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0046] In order to facilitate the understanding of the technical solutions of the present application, first, the existing OLED display principle and display structure are described, the OLED display principle is as shown in Figure 1 , and the OLED structure schematic diagram is as shown in Figure 2 . Among them, the cathode represents the cathode, the anode represents the anode, the OLED display panel can include a plurality of organic electroluminescent devices 1, and in each organic electroluminescent device 1, the substrate 11, the cathode layer 13, the electron injection layer (EIL), the electron transport layer (ETL), the hole blocking layer (HBL), the light emitting layer (EML), the electron blocking layer (EBL), the hole transport layer (HTL), the hole injection layer (HIL), the anode layer 12, the encapsulation layer 16, the quarter wave plate 15 and the polarizer 14 are stacked in order. Among them, the three light emitting materials (red light emitting material 21, green light emitting material 22 and blue light emitting material 23) in the light emitting layer EML are all arranged in the same light emitting layer, resulting in a low pixel structure density per unit area and a low display resolution.

[0047] In order to solve the technical problem of how to improve the effective pixel density per unit area of the OLED to improve the display resolution in the prior art, the present application provides an organic electroluminescent device, a display panel and a driving method, the light emitting materials are arranged in the first light emitting layer, the second light emitting layer and the third light emitting layer, the first light emitting layer and the second light emitting layer are arranged in the first region of the pixel unit, the third light emitting layer is arranged in the second region which is parallel to the first region, and the first functional layer is arranged to penetrate the second light emitting layer. The first light emitting layer or the second light emitting layer can be controlled according to the size of the voltage acting on the first functional layer. Since the first light emitting layer and the second light emitting layer are arranged in the same region of the pixel unit, the effective pixel density per unit area can be greatly improved, so that the display resolution can be improved.

[0048] Embodiment 1

[0049] The first embodiment of the present application provides an organic electroluminescent device, as shown in Figure 3 , the organic electroluminescent device comprises a substrate 11, a cathode layer 13, a hole blocking layer HBL, a first functional layer 31, a light emitting layer EML and an anode layer 12.

[0050] The cathode layer 13 is arranged on the substrate 11, the anode layer 12 is arranged on the cathode layer 13, and the hole blocking layer and the light emitting layer are arranged in a stack between the cathode layer 13 and the anode layer 12.

[0051] The light emitting layer EML includes a plurality of pixel units, each of which includes a first light emitting layer EML-1, a second light emitting layer EML-2, and a third light emitting layer EML-3. The first light emitting layer EML-1, the second light emitting layer EML-2, and the third light emitting layer EML-3 correspond to light emitting materials of different colors, respectively. The first light emitting layer EML-1 and the second light emitting layer EML-2 are arranged in a stack in a first region of the pixel unit, and the third light emitting layer EML-3 is arranged in a second region of the pixel unit. The first region and the second region are arranged side by side, that is, in each pixel unit, the first light emitting layer EML-1 and the second light emitting layer EML-2 are arranged in a stack in the first region, and the third light emitting layer EML-3 is arranged in the second region side by side with the EML-1 and the EML-2. The first functional layer 31 is arranged between the first light emitting layer EML-1 and the cathode layer 13, the first functional layer 31 penetrates the second light emitting layer EML-2, and the hole blocking layer wraps the first functional layer 31.

[0052] When the voltage acting on the first functional layer 31 is greater than or equal to the critical voltage of the first functional layer 31, the first light emitting layer EML-1 emits light; when the voltage acting on the first functional layer 31 is less than the critical voltage of the first functional layer 31, the second light emitting layer EML-2 emits light.

[0053] The organic electroluminescent device arranges light emitting materials in the first light emitting layer, the second light emitting layer, and the third light emitting layer, respectively, arranges the first light emitting layer and the second light emitting layer in a stack in a first region of a pixel unit, arranges the third light emitting layer in a second region side by side with the first region, and arranges the first functional layer to penetrate the second light emitting layer. The first light emitting layer or the second light emitting layer can be controlled to emit light according to the size of the voltage acting on the first functional layer. Since the first light emitting layer and the second light emitting layer are arranged in the same region of the pixel unit, the effective pixel density in a unit area can be greatly improved, thereby improving the display resolution.

[0054] In this embodiment, the circuit schematic diagram of the organic electroluminescent device is as shown in Figure 4 When the voltage applied to the functional layer is less than the critical voltage, the impedance of the functional layer is very high, and the second light emitting layer EML-2 emits light. When the voltage applied to the functional layer is greater than or equal to the critical voltage, the impedance of the functional layer drops sharply, the second light emitting layer EML-2 is short-circuited, and the first light emitting layer emits light.

[0055] Specifically, the first functional layer 31 can be a piezoresistor or a Zener thin film diode. At this time, the critical voltage of the first functional layer 31 can be the wake-up voltage of the piezoresistor or the breakdown voltage of the Zener thin film diode.

[0056] In one embodiment, the light-emitting layer comprises a red light-emitting material, a green light-emitting material and a blue light-emitting material. The first light-emitting layer EML-1 is the first of the red light-emitting material, the green light-emitting material and the blue light-emitting material; the second light-emitting layer EML-2 is the second of the red light-emitting material, the green light-emitting material and the blue light-emitting material; and the third light-emitting layer EML-3 is the third of the red light-emitting material, the green light-emitting material and the blue light-emitting material.

[0057] In this embodiment, the first light-emitting layer EML-1 is a red light-emitting material, the second light-emitting layer EML-2 is a green light-emitting material, and the third light-emitting layer EML-3 is a blue light-emitting material. The voltage applied to the first functional layer 31 can be referred to as Vdivision, and the critical voltage of the first functional layer 31 can be referred to as Vcritical. When Vdivision

[0058] In this embodiment, by switching the open circuit or short circuit of the first functional layer under different voltages, and by matching the hole blocking layer wrapped around the first functional layer, the short circuit switching of different light-emitting layers is realized, thereby realizing stacked display and improving the effective pixel density per unit area. For example, the red and green light-emitting layers are vertically stacked in different layers, and the blue light sub-pixel is arranged in both layers. By the red and green overlapping design, the area of one pixel can be reduced by 1 / 3, the pixel density can be increased by about 50%, and the double-layer thickness of the blue light sub-pixel can improve the service life of the blue light pixel.

[0059] In one embodiment, the structure of the organic electroluminescent device is shown in Figure 5 The organic electroluminescent device further comprises a second functional layer 32, and the third light-emitting layer EML-3 comprises an upper light-emitting layer EML-31 and a lower light-emitting layer EML-32.

[0060] The second functional layer 32 is arranged between the upper light-emitting layer EML-31 and the cathode layer 13, the second functional layer 32 penetrates the lower light-emitting layer EML-32, and the hole blocking layer HBL wraps the second functional layer 32. When the voltage acting on the second functional layer 32 is greater than or equal to the critical voltage of the second functional layer 32, the upper light-emitting layer EML-31 emits light; when the voltage acting on the second functional layer 32 is less than the critical voltage of the second functional layer 32, the lower light-emitting layer EML-32 emits light.

[0061] In the embodiment, the third light-emitting layer EML-3 also has a functional layer, i.e., the second functional layer 32, and the light-emitting materials of the upper light-emitting layer EML-31 and the lower light-emitting layer EML-32 of the third light-emitting layer EML-3 are the same. Taking the third light-emitting layer EML-3 as a blue light-emitting material as an example, when blue light is needed, the upper light-emitting layer EML-31 and the lower light-emitting layer EML-32 of the third light-emitting layer EML-3 do not emit light at the same time, but the upper light-emitting layer EML-31 or the lower light-emitting layer EML-32 emits light according to the voltage applied to the second functional layer, so that the service life of the blue pixel can be further improved. For example, when the voltage applied to the second functional layer is greater than or equal to the critical voltage of the second functional layer, the upper light-emitting layer EML-31 emits light, and when the voltage applied to the second functional layer is less than the critical voltage of the second functional layer, the lower light-emitting layer EML-32 emits light.

[0062] Specifically, the second functional layer 32 is composed of a pressure-sensitive resistor or a Zener diode. The critical voltage of the second functional layer 32 can be the wake-up voltage of the pressure-sensitive resistor or the breakdown voltage of the Zener diode.

[0063] In one embodiment, the organic electroluminescent device further comprises a hole injection layer, a hole transport layer, an electron blocking layer, an electron transport layer and an electron injection layer.

[0064] Specifically, the electron blocking layer is arranged between the anode layer 12 and the first light-emitting layer EML-1 and the third light-emitting layer EML-3 close to the anode layer 12, the hole transport layer is arranged between the anode layer 12 and the electron blocking layer, and the hole injection layer is arranged between the anode layer 12 and the hole transport layer; the electron transport layer is arranged between the cathode layer 13 and the hole blocking layer, and the electron injection layer is arranged between the cathode layer 13 and the electron transport layer.

[0065] Specifically, the organic electroluminescent device further comprises a quarter-wave plate 15 and a polarizing plate 14.

[0066] Specifically, the electron blocking layer is arranged between the anode layer 12 and the first light-emitting layer EML-1 and the third light-emitting layer EML-3 close to the anode layer 12, the hole transport layer is arranged between the anode layer 12 and the electron blocking layer, and the hole injection layer is arranged between the anode layer 12 and the hole transport layer; the electron transport layer is arranged between the cathode layer 13 and the hole blocking layer, and the electron injection layer is arranged between the cathode layer 13 and the electron transport layer.

[0067] In one embodiment, the critical voltage of the first functional layer 31 and the critical voltage of the second functional layer 32 are adjusted by the thickness of the pressure-sensitive resistor or by the doping of the pressure-sensitive resistor, or by the film material of the Zener diode or by the film doping.

[0068] In this embodiment, when the functional layer is selected as ZnO varistor, the critical voltage Vcritical can be adjusted by adjusting the thickness and doping of the ZnO varistor; when the functional layer is selected as Zener diode, the critical voltage Vcritical can be adjusted by adjusting the film material or doping of the Zener diode.

[0069] In one embodiment, a schematic diagram of the structure of a bidirectional light-emitting organic electroluminescent device is as shown in Figure 6 In this embodiment, the substrate 11, the cathode layer 13 and the anode layer 12 are all transparent materials.

[0070] For example, the first light-emitting layer EML-1 is a red light-emitting material, the second light-emitting layer EML-2 is a green light-emitting material, and the third light-emitting layer EML-3 is a blue light-emitting material. When the voltage V is less than the critical voltage Vcritical, the impedance of the first functional layer is very high, and in the red-green superimposed pixel, the holes reach the EML-2 first and then recombine with the electrons, and the second light-emitting layer EML-2 emits green light. Since the substrate, the cathode layer and the anode layer are all transparent materials, the organic electroluminescent device emits green light from both the top and the bottom. When the voltage V is greater than or equal to the critical voltage Vcritical, the impedance of the first functional layer drops sharply, the EML-2 light-emitting layer is short-circuited, the holes and the electrons recombine in the EML-1, and the first light-emitting layer EML-1 emits red light. Since the substrate, the cathode layer and the anode layer are all transparent materials, the organic electroluminescent device emits red light from both the top and the bottom. Similarly, when the third light-emitting layer EML-3 emits blue light, the organic electroluminescent device emits blue light from both the top and the bottom.

[0071] For example, the first light-emitting layer EML-1 is a red light-emitting material, the second light-emitting layer EML-2 is a green light-emitting material, and the third light-emitting layer EML-3 is a blue light-emitting material. A schematic diagram of green light excitation is as shown in Figure 7 The starting voltage of the first functional layer is referred to as Vstart. Considering that the movement speed of the holes is faster than that of the electrons, in order to ensure that the holes can reach the corresponding light-emitting layer first when the corresponding color of light is needed to be emitted, the thicknesses of the hole injection layer, the hole transport layer, the electron blocking layer, the electron transport layer and the electron injection layer can be adjusted to adjust the required time length for the electrons and the holes to reach the corresponding light-emitting layer. If the required time length for the holes to reach the corresponding light-emitting layer is recorded as the first transmission time length, the required time length for the electrons to reach the corresponding light-emitting layer is recorded as the second transmission time length, the distance that the holes need to pass through is recorded as T_hole, and the distance that the electrons need to pass through is recorded as T_e, the first transmission time length can be adjusted by adjusting the thicknesses of the hole injection layer, the hole transport layer and the electron blocking layer (T_hole), and the second transmission time length can be adjusted by adjusting the thicknesses of the electron injection layer and the electron transport layer (T_e). In this embodiment, when Vstart

[0072] A schematic diagram of red light excitation is shown below. Figure 8 When Vdividing voltage > Vcritical > Vstart, the resistance of the first functional layer drops sharply, EML-2 is short-circuited, electrons and holes recombine in the first light-emitting layer EML-1, and the first light-emitting layer EML-1 emits red light.

[0073] In the embodiments described above, the anode layer 12 can be a transparent thin film such as indium tin oxide (ITO). The cathode layer 13 can be a silver thin film, an aluminum thin film, or a silver-magnesium alloy thin film (the thickness can be set to 2~18nm if bidirectional light emission transparency is required). The hole injection layer HIL can be a hexachlorophenanthrene-hexacyanophenylene (HAT-CN), molybdenum trioxide (MoO3), etc. The hole transport layer HTL can be a naphthyldiphenylamine (NPB), tris(carbazylphenyl)terphenyl (TCTA), tris(fluorenylphenylaniline)terphenyl (TAPC), etc. The electron blocking layer EBL can be a tris(carbazylphenyl)terphenyl (TCTA), etc. The light-emitting layer EML can be a phosphorescent, fluorescent, thermally activated delayed fluorescence, etc., and different colors of light emission can be achieved by doping different quantum dots. The hole blocking layer HBL can be a N,N'-di(3-methylphenyl)-N,N'-diphenylaniline (TmPyPB), etc. The electron transport layer (ETL) can be made of materials such as tris(8-hydroxyquinolineone)aluminum (Alq3), 4,7-diphenyl-1,10-o-oxoline (Bphen), 2,2',2''-(1,3,5-phenyltriyl)-triphenylbenzimidazole (TPBi), N,N'-di(3-methylphenyl)-N,N'-diphenylaniline (TmPyPB), or N,N'-bis(4-tert-butylphenyl)-N,N'-diphenylaniline (TpPyPB). The electron injection layer (EIL) can be made of materials such as lithium 8-hydroxyquinoline (Liq), lithium fluoride (LiF), or cesium carbonate (CsCO3). The thickness of the anode layer 12 and the cathode layer 13 can be set between 50 and 300 nm, while the thickness of the remaining layers can be set between 2 and 100 nm without specific limitations.

[0074] Example 2

[0075] Based on the same technical concept, the second embodiment of this application provides a display panel, which includes a plurality of organic electroluminescent devices as described in the first embodiment.

[0076] The organic electroluminescent device in the display panel sets the light-emitting material in the first light-emitting layer, the second light-emitting layer and the third light-emitting layer respectively, the first light-emitting layer and the second light-emitting layer are arranged in a first area of the pixel unit in a stacked manner, the third light-emitting layer is arranged in a second area which is parallel to the first area, and the first functional layer is arranged through the second light-emitting layer, so that the first light-emitting layer or the second light-emitting layer can be controlled to emit light according to the size of the voltage acting on the first functional layer. Since the first light-emitting layer and the second light-emitting layer are arranged in the same area of the pixel unit, the effective pixel density in the unit area of the display panel can be greatly improved, so that the display resolution of the display panel can be improved.

[0077] Embodiment 3

[0078] Based on the same technical concept, the third embodiment of the present application provides an organic electroluminescent device driving method applied to the display panel in the second embodiment, like Figure 9 , the method comprises:

[0079] Step 901, determining the voltage acting on the first functional layer according to the color to be displayed of the organic electroluminescent device in the display panel;

[0080] Step 902, when the voltage acting on the first functional layer is greater than or equal to the critical voltage of the first functional layer, the first light-emitting layer emits light;

[0081] Step 903, when the voltage acting on the first functional layer is less than the critical voltage of the first functional layer, the second light-emitting layer emits light.

[0082] In the method, the organic electroluminescent device sets the light-emitting material in the first light-emitting layer, the second light-emitting layer and the third light-emitting layer respectively, the first light-emitting layer and the second light-emitting layer are arranged in a first area of the pixel unit in a stacked manner, the third light-emitting layer is arranged in a second area which is parallel to the first area, and the first functional layer is arranged through the second light-emitting layer, so that the first light-emitting layer or the second light-emitting layer can be controlled to emit light according to the size of the voltage acting on the first functional layer. Since the first light-emitting layer and the second light-emitting layer are arranged in the same area of the pixel unit, the effective pixel density in the unit area can be greatly improved, so that the display resolution can be improved.

[0083] The device embodiments described above are only schematic, wherein the units shown as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located in one place, or can be distributed on a plurality of network units. Part or all of the modules can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0084] Those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a general hardware platform, and of course can be implemented by hardware. Based on such an understanding, the technical solutions described above essentially or in other words make contributions to the related art, and can be embodied in a software product form, which can be stored in a computer readable storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, and the like, and includes a plurality of instructions to cause a computer device (which can be a personal computer, a server, or a network device, and the like) to execute the methods described in each embodiment or some parts of the embodiments.

[0085] It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and "has" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order in which they are described, unless specifically identified as an order dependent step. It is also to be understood that additional or alternative steps can be employed.

[0086] It should be understood that the specific embodiments described herein are merely exemplary and do not limit the application. In the description, the suffixes "module", "part" or "unit" used for components are merely intended for facilitation of the description and are not intended to have specific meanings or functions. Therefore, "module", "part" or "unit" can be mixedly used.

[0087] The above descriptions are merely specific embodiments of the present application, making those skilled in the art understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes: a substrate, a cathode layer, a hole blocking layer, a first functional layer, a light-emitting layer, and an anode layer; The cathode layer is disposed on the substrate, the anode layer is disposed on the cathode layer, and the hole blocking layer and the light-emitting layer are stacked between the cathode layer and the anode layer; The light-emitting layer includes multiple pixel units; each pixel unit includes a first light-emitting layer, a second light-emitting layer, and a third light-emitting layer; the first light-emitting layer, the second light-emitting layer, and the third light-emitting layer correspond to light-emitting materials of different colors; the first light-emitting layer and the second light-emitting layer are stacked sequentially in a first region of the pixel unit, and the third light-emitting layer is disposed in a second region of the pixel unit, with the first region and the second region arranged side by side; The first functional layer is disposed between the first light-emitting layer and the cathode layer, the first functional layer penetrates the second light-emitting layer, and the hole blocking layer encloses the first functional layer; The first light-emitting layer emits light when the voltage applied to the first functional layer is greater than or equal to the critical voltage of the first functional layer; the second light-emitting layer emits light when the voltage applied to the first functional layer is less than the critical voltage of the first functional layer.

2. The organic electroluminescent device according to claim 1, characterized in that, The organic electroluminescent device further includes a second functional layer; the third light-emitting layer includes an upper light-emitting layer and a lower light-emitting layer. The second functional layer is disposed between the upper light-emitting layer and the cathode layer, the second functional layer penetrates the lower light-emitting layer, and the hole blocking layer encloses the second functional layer; The upper light-emitting layer emits light when the voltage applied to the second functional layer is greater than or equal to the critical voltage of the second functional layer; the lower light-emitting layer emits light when the voltage applied to the second functional layer is less than the critical voltage of the second functional layer.

3. The organic electroluminescent device according to claim 1, characterized in that, The organic electroluminescent device further includes: a hole injection layer, a hole transport layer, an electron blocking layer, an electron transport layer, and an electron injection layer; Wherein, the electron blocking layer is disposed between the anode layer and the first light-emitting layer and the third light-emitting layer near the anode layer, the hole transport layer is disposed between the anode layer and the electron blocking layer, and the hole injection layer is disposed between the anode layer and the hole transport layer; The electron transport layer is disposed between the cathode layer and the hole blocking layer, and the electron injection layer is disposed between the cathode layer and the electron transport layer.

4. The organic electroluminescent device according to claim 2, characterized in that, The first functional layer is composed of a varistor or a Zener thin-film diode; the second functional layer is composed of a varistor or a Zener thin-film diode.

5. The organic electroluminescent device according to claim 4, characterized in that, The critical voltage of the first functional layer and the critical voltage of the second functional layer are adjusted by the thickness of the varistor, the doping of the varistor, the thin film material of the Zener thin film diode, or the thin film doping.

6. The organic electroluminescent device according to claim 3, characterized in that, The organic electroluminescent device further includes: a quarter-wave plate and a polarizer; The polarizer is disposed on the outer side of the substrate, and the quarter-wave plate is disposed between the substrate and the polarizer.

7. The organic electroluminescent device according to claim 6, characterized in that, The substrate, the cathode layer, and the anode layer are all made of transparent material.

8. The organic electroluminescent device according to claim 1, characterized in that, The light-emitting layer includes red light-emitting materials, green light-emitting materials, and blue light-emitting materials; The first light-emitting layer is the first of the red light-emitting material, the green light-emitting material, and the blue light-emitting material; The second light-emitting layer is the second of the red light-emitting material, the green light-emitting material, and the blue light-emitting material; The third luminescent layer is the third of the red luminescent material, the green luminescent material, and the blue luminescent material.

9. A display panel, characterized in that, The display panel includes an organic electroluminescent device as described in any one of claims 1-8.

10. A driving method for an organic electroluminescent device, characterized in that, Applied to the display panel of claim 9, the method includes: The voltage applied to the first functional layer is determined based on the color to be displayed by the organic electroluminescent device in the display panel; When the voltage applied to the first functional layer is greater than or equal to the critical voltage of the first functional layer, the first light-emitting layer emits light; The second light-emitting layer emits light when the voltage applied to the first functional layer is less than the critical voltage of the first functional layer.

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