CN116209297A

CN116209297A - Display substrate, preparation method thereof and display device

Info

Publication number: CN116209297A
Application number: CN202211310563.1A
Authority: CN
Inventors: 吴海东; 杜小波; 隽奥; 王红丽; 吴桐
Original assignee: BOE Technology Group Co Ltd
Current assignee: BOE Technology Group Co Ltd
Priority date: 2022-10-25
Filing date: 2022-10-25
Publication date: 2023-06-02

Abstract

The embodiment of the disclosure provides a display substrate, a preparation method thereof and a display device. Wherein, the display substrate includes: a substrate; the light-emitting elements are positioned on one side of the substrate and comprise a first electrode, a light-emitting functional layer and a second electrode which are sequentially arranged along the direction far away from the substrate; the second electrode includes: the first sub-electrode and the second sub-electrode are positioned on one side of the first sub-electrode far away from the substrate and are connected with the first sub-electrode in parallel, the light transmittance of the first sub-electrode is smaller than that of the second sub-electrode, the conductivity of the first sub-electrode is larger than that of the second sub-electrode, and the thickness of the first sub-electrode is smaller than or equal to 20nm.

Description

Display substrate, preparation method thereof and display device

Technical Field

The disclosure relates to the technical field of display, in particular to a display substrate, a preparation method thereof and a display device.

Background

Organic electroluminescent devices (OLEDs) have a series of advantages of all solid state, self-luminescence, fast response, wide viewing angle, wide operating temperature range, and the like, and are increasingly used.

In the light emitting process of the OLED device, the transmission speed of holes is higher than that of electrons, so that the imbalance of carrier transmission in the device is caused, and the light emitting performance of the device is further influenced, therefore, the injection barrier of a cathode interface can be reduced through the low work function metal material, the electron injection capacity is improved, and the balance of carrier transmission in the device can be improved.

Based on this, the cathode structure of the OLED in the related art adopts a metal or alloy material, such as Al, ag, liF/Al, ca/Mg, etc. In order to ensure the light transmittance of the cathode, the thickness of the metal cathode needs to be made thinner, but the thinner the thickness of the metal cathode is, the larger the overall resistance of the metal cathode is. Currently, in order to ensure that the resistance of the metal cathode is not excessive, the thickness of the metal cathode is often designed to be greater than 25nm.

Disclosure of Invention

The embodiment of the disclosure provides a display substrate, a preparation method thereof and a display device.

In a first aspect, an embodiment of the present disclosure provides a display substrate including:

a substrate;

a plurality of light emitting elements located at one side of the substrate, the light emitting elements including a first electrode, a light emitting functional layer, and a second electrode sequentially disposed in a direction away from the substrate;

the second electrode includes: the first sub-electrode and the second sub-electrode are positioned on one side, far away from the substrate, of the first sub-electrode and are connected with the first sub-electrode in parallel, the light transmittance of the first sub-electrode is smaller than that of the second sub-electrode, the conductivity of the first sub-electrode is larger than that of the second sub-electrode, and the thickness of the first sub-electrode is smaller than or equal to 20nm.

In some embodiments, the first sub-electrode is a metal electrode and the second sub-electrode is a transparent electrode.

In some embodiments, the first sub-electrodes are in one-to-one correspondence with the light emitting elements, and the first sub-electrodes in the light emitting elements are arranged at intervals;

all of the light emitting elements share the same second sub-electrode.

In some embodiments, the light emitting element further comprises: a light extraction pattern located between and in contact with the first sub-electrode and the second sub-electrode;

the orthographic projection area of the first sub-electrode on the substrate is larger than the orthographic projection area of the corresponding light extraction pattern on the substrate.

In some embodiments, the orthographic projection of the first sub-electrode onto the substrate covers the orthographic projection of the corresponding light extraction pattern onto the substrate.

In some embodiments, the display substrate further comprises:

a pixel defining layer on one side of the substrate, comprising: a plurality of pixel openings corresponding to the light emitting elements one by one, wherein parts of the light emitting elements are positioned in the corresponding pixel openings;

orthographic projection of the light extraction pattern in the light-emitting element on the substrate covers orthographic projection of the bottom of the corresponding pixel opening on the substrate;

The orthographic projection of the first sub-electrode in the light-emitting element on the substrate covers the orthographic projection of the bottom of the corresponding pixel opening on the substrate.

In some embodiments, the material of the first sub-electrode comprises a first metal material;

the display substrate further includes: a first functional layer including a plurality of first patterns configured to promote formation of the first metal material on a side surface of the first patterns remote from the substrate;

the first pattern is positioned between the corresponding first sub-electrode and the luminous functional layer, and the orthographic projection of the first pattern on the substrate overlaps with the orthographic projection of the corresponding first sub-electrode on the substrate.

In some embodiments, the orthographic projection of the first sub-electrode on the substrate covers the orthographic projection of the corresponding first pattern on the substrate, and the distance between the edge of the first sub-electrode and the edge on the same side corresponding to the first pattern in the direction parallel to the substrate is less than or equal to 10 μm.

In some embodiments, the ratio of the area of orthographic projection of the first pattern on the substrate to the area of orthographic projection of the corresponding first sub-electrode on the substrate is between 0.9 and 1.1.

the display substrate further includes: a second functional layer, the second functional layer comprising: a second pattern, on which a plurality of hollowed-out areas corresponding to the first sub-electrodes one by one are formed, the second pattern being configured to repel the first metal material;

the second pattern is located between the light-emitting functional layer and the second sub-electrode, and the orthographic projection of the first sub-electrode on the substrate overlaps with the orthographic projection of the corresponding hollowed-out area on the substrate.

In some embodiments, the orthographic projection of the first sub-electrode on the substrate covers the orthographic projection of the corresponding hollowed-out area on the substrate;

the distance between the edge of the first sub-electrode and the edge of the same side on the corresponding hollowed-out area in the direction parallel to the substrate is less than or equal to 15 mu m.

In some embodiments, the orthographic projection of the second pattern on the substrate overlaps with orthographic projections of the light emitting functional layers corresponding to at least two of the light emitting elements on the substrate.

In some embodiments, the display substrate further comprises:

the orthographic projection of the pixel defining layer on the substrate covers the orthographic projection of the second pattern on the substrate.

In some embodiments, the first sub-electrode and the portion of the second pattern on one side of the first sub-electrode in a first direction and adjacent to the first sub-electrode have a width ratio in the first direction between 1:9-9:1.

In some embodiments, the thickness of the first sub-electrode is less than the thickness of the second sub-electrode.

In some embodiments, the orthographic projection of the portion of the first sub-electrode on the substrate does not overlap with the orthographic projection of the corresponding first electrode on the substrate.

In some embodiments, the orthographic projection area of the light emitting functional layer on the substrate is larger than the orthographic projection area of the corresponding first sub-electrode on the substrate.

In some embodiments, the display substrate further comprises: an encapsulation layer and a driving function layer, wherein,

The packaging layer is positioned on one side of the second sub-electrode far away from the substrate;

the driving functional layer is located between the light emitting elements and the substrate, and includes a plurality of driving circuits configured to provide driving signals to the corresponding light emitting elements.

In a second aspect, embodiments of the present disclosure further provide a display apparatus, including: the display substrate as provided in the first aspect described above.

In a third aspect, an embodiment of the present disclosure further provides a method for preparing a display substrate as described in the first aspect, including:

providing a substrate;

forming a plurality of light emitting elements on the substrate, the light emitting elements including a first electrode, a light emitting functional layer, and a second electrode sequentially disposed in a direction away from the substrate;

In some embodiments, the step of forming the light emitting element includes: a step of forming a first electrode, a step of forming a light emitting functional layer, and a step of forming a second electrode;

wherein the step of forming the second electrode includes:

forming a first functional layer on a side of the light emitting functional layer away from the substrate, the first functional layer including a plurality of first patterns configured to promote formation of the first metal material on a side surface of the first patterns away from the substrate;

forming the first metal material on one side of the first functional layer far away from the substrate to obtain a plurality of first sub-electrodes in one-to-one correspondence with the first patterns, wherein the orthographic projection of the first patterns on the substrate overlaps with the orthographic projection of the corresponding first sub-electrodes on the substrate;

and forming the second sub-electrode on one side of the first sub-electrode far away from the substrate, wherein the second sub-electrode is connected with the first sub-electrode in parallel.

wherein the step of forming the second electrode includes:

Forming a second functional layer on a side of the light emitting functional layer away from the substrate, the second functional layer comprising: a second pattern, on which a plurality of hollowed-out areas corresponding to the first sub-electrodes one by one are formed, the second pattern being configured to repel the first metal material;

forming the first metal material on one side of the second functional layer far away from the substrate to obtain a plurality of first sub-electrodes corresponding to the hollowed-out areas one by one, wherein the orthographic projection of the first sub-electrodes on the substrate overlaps with the orthographic projection of the corresponding hollowed-out areas on the substrate;

In a third aspect, embodiments of the present disclosure provide a display device including the display substrate of the first aspect.

Drawings

The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification, illustrate the disclosure and together with the description serve to explain, but do not limit the disclosure. In the drawings:

fig. 1a is a schematic structural diagram of a display substrate according to an embodiment of the disclosure.

Fig. 1b is a schematic view of a partial structure of the region A1 in fig. 1 a.

Fig. 1c is a schematic view of a partial structure of the region A2 in fig. 1 a.

Fig. 2a is a schematic structural diagram of another display substrate according to an embodiment of the disclosure.

Fig. 2B is a schematic partial structure of the region B1 in fig. 2 a.

Fig. 2c is a schematic diagram of a partial structure of the region B2 in fig. 2 a.

Fig. 3 is a schematic flowchart of a method for manufacturing a display substrate according to an embodiment of the disclosure.

Fig. 4 is a schematic flowchart of another method for manufacturing a display substrate according to an embodiment of the disclosure.

Fig. 5a to 5d are schematic cross-sectional views of intermediate products obtained by the preparation method shown in fig. 4.

Fig. 6 is a schematic flowchart of another method for manufacturing a display substrate according to an embodiment of the disclosure.

Fig. 7 a-7 d are schematic cross-sectional views of intermediate products produced by the preparation method shown in fig. 6.

Wherein the reference numerals:

a substrate 1, a light emitting element 2, a light extraction pattern 3, a pixel defining layer 4, an encapsulation layer 7, a driving function layer 8, and a planarization layer 9; a first functional layer 5, a first pattern 50; a second functional layer 6, a second pattern 60;

a first electrode 21, a light-emitting functional layer 22, a second electrode 23: a first sub-electrode 2a, a second sub-electrode 2b.

Detailed Description

Specific embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating and illustrating the disclosure, are not intended to limit the disclosure.

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present disclosure more apparent, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present disclosure. It will be apparent that the described embodiments are some, but not all, of the embodiments of the present disclosure. All other embodiments, which can be made by one of ordinary skill in the art without the need for inventive faculty, are within the scope of the present disclosure, based on the described embodiments of the present disclosure.

Unless defined otherwise, technical or scientific terms used in embodiments of the present disclosure should be given the ordinary meaning as understood by one of ordinary skill in the art to which the present disclosure belongs. The terms "first," "second," and the like, as used in this disclosure, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. Likewise, the word "comprising" or "comprises", and the like, means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof, but does not exclude other elements or items. The terms "connected" or "connected," and the like, are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", etc. are used merely to indicate relative positional relationships, which may also be changed when the absolute position of the object to be described is changed.

In addition, in the expression of the range M-N in the embodiments of the present disclosure, the defined range includes both the end values of M and N.

Organic electroluminescent devices (OLEDs) have a series of advantages of all solid state, self-luminescence, fast response, wide viewing angle, wide operating temperature range, and the like, and are increasingly used. The OLED device is a stacked structure, and at least comprises: an anode and a cathode disposed opposite each other, and an electroluminescent layer disposed between the anode and the cathode; after providing electric signals for the anode and the cathode, carrier holes of the anode and carrier electrons of the cathode are respectively injected into the electroluminescent layer from the anode and the cathode, excitons are formed by combination of the electroluminescent layer, the excitons are in an excited state and are rapidly de-excited to return to a ground state, and energy radiated by de-excitation excites the electroluminescent layer to emit light.

Based on this, the cathode structure of the OLED in the related art adopts a metal or alloy material, such as Al, ag, liF/Al, ca/Mg, etc. However, since the metal material has a large light absorption coefficient, the cathode needs to be made as thin as possible to obtain a higher light transmittance. But the thinner the cathode, the greater the resistance; meanwhile, an excessively thin cathode is not beneficial to protecting an electroluminescent layer from water and oxygen, and the service life of an OLED device is influenced.

Therefore, the cathode structure of the current OLED device cannot simultaneously have the characteristics of low work function, high transmittance and low resistance.

In order to solve at least one of the above technical problems, an embodiment of the present disclosure provides a display substrate, in which a first sub-electrode and a second sub-electrode are connected in parallel to a second electrode in a light emitting element, so that the second electrode of the light emitting element can reduce resistance and has a higher light transmittance.

Fig. 1a is a schematic structural diagram of a display substrate according to an embodiment of the disclosure, fig. 1b is a schematic partial structural diagram of a region A1 in fig. 1a, and fig. 1c is a schematic partial structural diagram of a region A2 in fig. 1 a. As shown in fig. 1a, the display substrate includes: a substrate 1 and a plurality of light emitting elements 2 located on one side of the substrate 1, wherein:

The light emitting element 2 includes a first electrode 21, a light emitting functional layer 22, and a second electrode 23 which are sequentially disposed in a direction away from the substrate 1; the second electrode 23 includes: the first sub-electrode 2a and the second sub-electrode 2b, the second sub-electrode 2b is located at one side of the first sub-electrode 2a far from the substrate 1 and connected with the first sub-electrode 2a in parallel, the light transmittance of the first sub-electrode 2a is smaller than that of the second sub-electrode 2b, the conductivity of the first sub-electrode 2a is larger than that of the second sub-electrode 2b, and the thickness of the first sub-electrode 2a is smaller than or equal to 20nm.

Preferably, the thickness of the first sub-electrode 2a may range from 1 to 10nm, for example 5nm, 8nm, etc.

According to the display substrate provided by the embodiment of the disclosure, the resistance of the second electrode 23 is effectively reduced in a mode that the second sub-electrode 2b and the first sub-electrode 2a are connected in parallel. Meanwhile, since the second sub-electrode 2b is connected in parallel with the first sub-electrode 2a, the first sub-electrode 2a contacting with the light emitting functional layer 22 can be thinner to obtain higher light transmittance, thereby improving the display effect of the display substrate.

In some embodiments, the orthographic projection of the first sub-electrode 2a onto the substrate 1 is located in the area where the orthographic projection of the second sub-electrode 2b onto the substrate 11 is located.

In some embodiments, the orthographic projection of the portion of the first sub-electrode 2a on the substrate 1 does not overlap with the orthographic projection of the corresponding first electrode 21 on the substrate.

In some embodiments, the orthographic projection area of the light emitting functional layer 22 on the substrate is larger than the orthographic projection area of the first sub-electrode 2a on the substrate.

It should be understood that the first electrode 21 may be an anode of the light emitting element 2, the second electrode 23 may be a cathode of the light emitting element 2, and the light emitting functional layer 22 includes at least an organic light emitting layer; after the anode and the cathode are supplied with an electric signal, carrier holes of the anode and carrier electrons of the cathode are injected from the anode and the cathode, respectively, into the organic light emitting layer within the light emitting functional layer 22 to form excitons, thereby exciting light.

Alternatively, the light transmittance of the second sub-electrode 2b is more than 90%.

In some embodiments, the first sub-electrode 2a may be a metal electrode and the second sub-electrode 2b may be a transparent electrode. Alternatively, the material of the first sub-electrode 2a includes a first metal material, and the first metal material may be a single metal material or an alloy material. For example, the first metal material may be any one of Mg, ag, al, li, K, ca or an alloy material formed by any combination thereof. The material of the second sub-electrode 2b may include any one of indium zinc oxide IZO, indium tin oxide ITO, indium gallium zinc oxide IGZO, aluminum zinc oxide AZO. In some embodiments, the metallic elements contained in the first sub-electrode 2a are shown to be different from the metallic elements contained in the second sub-electrode 2 b.

In some embodiments, the thickness of the second sub-electrode 2b is much greater than the thickness of the first sub-electrode 2a, wherein the thickness of the second sub-electrode 2b ranges from 50-500nm, such as 100nm, 200nm, 300nm, 400nm, etc., and embodiments of the disclosure are not limited in this respect.

In some embodiments, the light emitting functional layer 22 may further include a carrier functional layer including a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer. Wherein the hole injection layer, the hole transport layer and the electron blocking layer are positioned between the organic light emitting layer and the first electrode 21 and are sequentially arranged along a direction away from the first electrode 21; the hole blocking layer, the electron transporting layer, and the electron injecting layer are located between the organic light emitting layer and the second electrode 23, and are sequentially disposed in a direction away from the organic light emitting layer. That is, in some embodiments, it may be that the electron injection layer in the light emitting function layer 22 is in contact with the second electrode 23.

The low work function metal material can reduce the injection barrier of the cathode interface and improve the injection efficiency of carriers, and the first sub-electrode 2a in the second electrode 23 is a metal electrode, so that the first sub-electrode 2a is located at the side of the light emitting functional layer 22 away from the substrate 1, and the second sub-electrode 2b is located at the side of the first sub-electrode 2a away from the substrate 1.

In some embodiments, as shown in fig. 1a, the first sub-electrodes 2a are in one-to-one correspondence with the light emitting elements 2, and the first sub-electrodes 2a in different light emitting elements 2 are arranged at intervals; all light emitting elements 2 share the same second sub-electrode 2b. For the first sub-electrodes 2a arranged at intervals, the resistance of the single first sub-electrode 2a is smaller due to the relatively smaller size, so that the overall resistance of the second electrode is reduced; meanwhile, when the under-screen camera is arranged in the display substrate, shielding of the camera by the first sub-electrode 2a can be avoided, and therefore shooting effect of the camera can be improved.

It should be understood that the first sub-electrodes 2a in different light emitting elements 2 are arranged at intervals; the same second sub-electrode 2b is shared by all the light emitting elements 2, that is, the first sub-electrode 2a is a pattern of a plurality of intervals, and the second sub-electrode 2b is a continuous electrode (may also be referred to as a planar electrode).

In some embodiments, as shown in fig. 1a, the display substrate further comprises: a first functional layer 5, the first functional layer 5 including a plurality of first patterns 50, the first patterns 50 being configured to promote formation of a first metal material on a side surface of the first patterns 50 remote from the substrate 1; the first pattern 50 is located between the corresponding first sub-electrode 2a and the light emitting functional layer 22, and the front projection of the first pattern 50 on the substrate 1 overlaps with the front projection of the first sub-electrode 2a on the substrate 1.

In one example, the surface of the light-emitting functional layer 22 on the side away from the substrate 1 may be an amine, diamine, or triamine material, and the adhesion of the metal material is poor due to the material characteristics of the material itself, and a film layer of the metal material cannot be formed thereon by vapor deposition. Therefore, the first functional layer 5 is disposed on the surface of the light emitting functional layer 22 away from the substrate 1 and at the position of the pixel opening to improve the adhesion of the metal material, promoting the formation of the first metal material on the surface of the first pattern 50 away from the substrate 1; alternatively, the material of the first pattern 50 may be a fullerene material to facilitate adhesion of the metal material; and, the thickness of the first pattern 50 may be between 1-10nm, which is not limited by the embodiments of the present disclosure.

In some embodiments, the ratio of the area of the orthographic projection of the first pattern 50 on the substrate to the area of the orthographic projection of the corresponding first sub-electrode 2a on the substrate is between 0.9 and 1.1. Alternatively, the ratio of the area of the orthographic projection of the first pattern 50 on the substrate to the area of the orthographic projection of the corresponding first sub-electrode 2a on the substrate is 1.

In some embodiments, as shown in fig. 1b, the front projection of the first sub-electrode on the substrate covers the front projection of the corresponding first pattern 50 on the substrate, and the distance between the edge of the first sub-electrode 2a and the edge on the same side on the corresponding first pattern 50 in the direction parallel to the substrate is less than or equal to 10 μm. That is, the first sub-electrode 2a entirely covers the first pattern, and a portion of the first sub-electrode 2a beyond the first pattern does not exceed 10 μm, for example, 2 μm, 5 μm, 7 μm, and the like.

In one example, the first sub-electrode 2a includes a portion (i.e., a slope portion) whose thickness is gradually thinner in a direction away from the first pattern at a portion beyond the first pattern. As shown in fig. 1b, the slope angle α1 at which the first sub-electrode 2a located on the light emitting functional layer exceeds the edge of the first pattern portion is 45 ° or less, for example, 15 °, 30 °, or the like.

As an ideal case in the present disclosure, when the first metal material is evaporated over the first pattern 50 to form the first sub-electrode 2a, the metal material cannot be attached to the surface of the light emitting functional layer 22 on the side far from the substrate 1 where the first pattern 50 is not disposed, and at this time, the front projection of the first pattern 50 on the substrate 1 exactly coincides with the front projection of the first sub-electrode 2a on the substrate 1, so as to implement patterning of the first sub-electrode 2 a.

Fig. 2a is a schematic structural diagram of another display substrate according to an embodiment of the disclosure, fig. 2B is a schematic structural diagram of a portion B1 in fig. 2a, and fig. 2c is a schematic structural diagram of a portion B2 in fig. 2 a.

In some embodiments, as shown in fig. 2 a-2 c, unlike the display substrate of the previous embodiments including the first functional layer, the display substrate of the present embodiment includes: the second functional layer 6, the second functional layer 6 includes a second pattern 60, and a plurality of hollow areas corresponding to the first sub-electrodes 2a one by one are formed on the second pattern 60. The second pattern 60 is configured to repel the first metal material.

In some embodiments, the material of the second pattern 60 may be an amine, a diamine, a triamine material, such as N, N '-diphenyl-N, N' -bis (9-phenyl-9H-carbazol-3-yl) biphenyl-4, 4 '-diamine, N- (biphenyl-4-yl) -9, 9-dimethyl-N- (4- (9-phenyl-9H-carbazol-3-yl) phenyl) -9H-fluoren-2-amine, 4',4 "-tris (3-methylphenylamino) triphenylamine, N '-bis (1-naphthyl) -N, N' -diphenyl [1,1 '-biphenyl ] -4,4' -diamine, or 4,4 '-bis [ N- (3-methylphenyl) -N-phenylamino ] biphenyl, N4, N' -diphenyl-N4, N4 '-bis (9-phenyl-9H-carbazol-3-yl) diphenyl-4, 4' -diamine, N (diphenyl-4-yl) 9, 9-dimethyl-N- (4-phenyl-9H-phenyl-3-carbazol-yl) -2H-fluoren-amine, or the like.

The adhesion of the metal material is poor due to the material characteristics of the second pattern 60, and it is difficult to vapor-deposit a film layer of the metal material thereon. Therefore, the first metal material may be formed at a position where the light emitting function layer 22 is away from the substrate 1 and the second pattern 60 is not provided to obtain the first sub-electrode 2a, thereby patterning the first sub-electrode 2a (in this case, a surface of the light emitting function layer 22 away from the substrate 1 can have a better adhesion with the first metal material).

In some embodiments, the orthographic projection of the second pattern 60 on the substrate overlaps with the orthographic projection of the light emitting functional layer 22 corresponding to the at least two light emitting elements 2 on the substrate.

In some embodiments, as shown in fig. 2b, the first sub-electrode 2a is located on a side of the light-emitting functional layer away from the substrate and is located in the corresponding hollowed-out region, that is, the front projection of the first sub-electrode 2a on the substrate overlaps with the front projection of the corresponding hollowed-out region on the substrate.

In some embodiments, the orthographic projection of the first sub-electrode 2a on the substrate 1 covers the orthographic projection of the corresponding hollowed-out area on the substrate 1; the distance between the edge of the first sub-electrode 2a and the edge on the same side of the corresponding hollowed-out area in the direction parallel to the substrate 1 is less than or equal to 15 μm. That is, the edge of the first sub-electrode 2a extends above the second pattern, and the portion covering the second pattern is 15 μm or less, for example, 2 μm, 5 μm, 7 μm, or the like.

In one example, the portion of the first sub-electrode 2a covering the second pattern includes a portion (i.e., a slope portion) that is gradually thinner in a direction away from the corresponding hollowed-out region. As shown in fig. 2b, the slope angle α2 at the edge of the first sub-electrode on the second pattern is 45 ° or less, for example, 15 °, 30 °, or the like. As an ideal situation in the present disclosure, when the first metal material is evaporated over the second pattern 60 to form the first sub-electrode 2a, the metal material cannot be attached to the surface of the light emitting functional layer 22 on the side far away from the substrate 1, where the second pattern 60 is disposed, where the first metal material can only be formed in the hollowed-out area, and the front projection of the first sub-electrode 2a on the substrate exactly coincides with the front projection of the corresponding hollowed-out area on the substrate (i.e., the front projection of the second pattern 60 on the substrate 1 does not overlap with the front projection of the first sub-electrode 2a on the substrate 1, or both the second pattern 60 and the first sub-electrode 2a are only contacted at the edge), so as to implement patterning of the first sub-electrode 2 a.

In one example, as shown in fig. 2a, the width w1 of the first sub-electrode 2a in the first direction, and the width w2 of the portion of the second pattern 60 located on one side of the first sub-electrode 2a in the first direction and adjacent to the first sub-electrode 2a in the first direction, the ratio of w1 to w2 is between 1:9 and 9:1. Further, the ratio of w1 to w2 may be between 1:5 and 5:1. Wherein the first direction is parallel to the plane of the substrate 1.

The patterning of the first sub-electrode 2a is achieved based on the characteristic that the adhesion between the material of the first pattern 50 and the metal material is good, or the characteristic that the metal material film layer cannot be attached on the second pattern 60. Compared with the related art, the method for patterning the film layer formed by the metal material in the etching manner can avoid the etching liquid from corroding other film layers and the ultraviolet light from adversely affecting other parts of the light-emitting element 2 in the exposure process.

It should be noted that the first functional layer (first pattern) and the second functional layer (second pattern) may be selectively disposed according to adhesion between the surface of the light emitting functional layer 22 on the side away from the substrate 1 and the first metal material in practical applications. For example, when the surface of the light emitting functional layer 22 on the side away from the substrate 1 can have poor adhesion with the first metal material, such that the first metal material cannot be directly formed on the surface of the light emitting functional layer 22 on the side away from the substrate 1, the above-mentioned first functional layer may be disposed on the light emitting functional layer 22 and corresponding to the region where the first sub-electrode 2a is to be formed; when the adhesion between the surface of the light emitting functional layer 22 on the side away from the substrate 1 and the first metal material is strong, so that the first metal material can be directly formed on the surface of the light emitting functional layer 22 on the side away from the substrate 1, the above-described second functional layer may be disposed on the light emitting functional layer 22 in other regions than the A1 region where the first sub-electrode 2a is to be formed.

Of course, in some embodiments, the display substrate may also include the first functional layer (the first pattern 50) and the second functional layer (the second pattern 60) at the same time, where the first metal material can be formed above the first pattern 50 and the first metal material cannot be formed above the second pattern; this case (corresponding figures are not given) shall also fall within the scope of protection of the present disclosure.

In some embodiments, as shown in fig. 1a, 2a, the light emitting element 2 further comprises: the light extraction pattern 3, the light extraction pattern 3 is located between the first sub-electrode 2a and the second sub-electrode 2b and is in contact with the first sub-electrode 2 a.

Wherein the thickness of the light extraction pattern 3 is in the range of 60-100nm, such as 70nm, 80nm, 90nm, etc., the refractive index n of the light extraction pattern 3 is 1.8 or more, and the extinction coefficient k of the light extraction pattern 3 for light having a wavelength between 450-780nm is 0.01 or less. By using the light extraction pattern 3 of a high refractive index material, the light extraction efficiency can be improved, thereby effectively increasing the aperture ratio of the display substrate and improving the display effect of the display substrate.

In one example, the material of the light extraction pattern 3 may be any one of N, N ' -bis (1-naphthyl) -N, N ' -diphenyl-1, 1' -biphenyl-4-4 ' -diamine (NPB), triphenyldiamine derivative (TPD), N ' -diphenyl-N, N ' -bis (4 ' - (N, N-bis (1-naphthyl) -amino) -4-biphenyl) -benzidine (TPTE), 1,3, 5-tris (N-3-methylphenyl-N-phenylamino) benzene (TDAB), copper phthalocyanine (CuPc).

Optionally, the front projection area of the first sub-electrode 2a on the substrate 1 is larger than the front projection area of the corresponding light extraction pattern 3 on the substrate 1, so that at least part of the first sub-electrode 2a is not covered by the light extraction pattern 3, and therefore, the arrangement of the light extraction pattern 3 does not affect the electrical connection between the first sub-electrode 2a and the second sub-electrode 2b, and the parallel connection between the first sub-electrode 2a and the second sub-electrode 2b is ensured, so as to reduce the resistance of the second electrode 23 in the light emitting element 2.

In some embodiments, the display substrate further comprises: a pixel defining layer 4 located on one side of the substrate 1, comprising: a plurality of pixel openings corresponding to the light emitting elements 2 one by one, and a portion of the light emitting element 2 is located in the corresponding pixel opening. Orthographic projection of the light extraction pattern 3 in the light-emitting element 2 on the substrate 1 covers orthographic projection of the bottom of the corresponding pixel opening on the substrate 1; the front projection of the first sub-electrode 2a in the light emitting element 2 on the substrate 1 covers the front projection of the bottom of the corresponding pixel opening on the substrate 1.

In some embodiments, the orthographic projection of the pixel defining layer 4 onto the substrate 1 covers the orthographic projection of the second pattern 60 onto the substrate 1.

In some embodiments, as shown in fig. 1a and 2a, the display substrate further includes: an encapsulation layer 7 and a driving functional layer 8, wherein the encapsulation layer 7 is located at a side of the second sub-electrode 2b remote from the substrate 1, the driving functional layer 8 is located between the light emitting element 2 and the substrate 1, and the driving functional layer 8 comprises a plurality of driving circuits configured to provide driving signals to the corresponding light emitting elements 2.

Wherein, the encapsulation layer 7 may include an organic encapsulation layer, an inorganic encapsulation layer, or a stacked structure formed by alternately arranging the organic encapsulation layer and the inorganic encapsulation layer; the material of the inorganic encapsulation layer may include: any one of silicon oxide, silicon nitride, and silicon oxynitride, and the material of the organic encapsulation layer may include a resin material. The specific structure and thickness of the encapsulation layer 7 in the embodiment of the present disclosure are not limited, as long as the light emitting element 2 can be protected. The encapsulation layer 7 is arranged on one side of the second sub-electrode 2b far away from the substrate 1, so that the corrosion and damage of water and oxygen to the light-emitting element 2 can be prevented, and the service life of the device can be prolonged.

In some embodiments, as shown in fig. 1a and 2a, the display substrate may further include: a planarization layer 9 is located between the driving function layer 8 and the light emitting element 2. The driving circuit includes at least a driving transistor, and the first electrode 21 of the light emitting element 2 is electrically connected to the drain of the driving transistor in the corresponding driving circuit. Specifically, the first electrode 21 of the light emitting element 2 and the drain of the driving transistor are electrically connected through a via hole on the planarization layer 9.

Based on the same inventive concept, the embodiments of the present disclosure also provide a method for manufacturing a display substrate, which may be used to manufacture the display substrate provided in the previous embodiments, and the following detailed description will be given. Fig. 3 is a schematic flowchart of a method for manufacturing a display substrate according to an embodiment of the disclosure.

In some embodiments, as shown in fig. 3, the preparation method of the display substrate includes:

in step S1, a substrate 1 is provided.

Step S2: forming a plurality of light emitting elements 2 on a substrate 1, the light emitting elements 2 including a first electrode 21, a light emitting functional layer 22, and a second electrode 23 sequentially disposed in a direction away from the substrate 1; the second electrode 23 includes: the first sub-electrode 2a and the second sub-electrode 2b, the second sub-electrode 2b is located at one side of the first sub-electrode 2a far from the substrate 1 and connected with the first sub-electrode 2a in parallel, the light transmittance of the first sub-electrode 2a is smaller than that of the second sub-electrode 2b, the conductivity of the first sub-electrode 2a is larger than that of the second sub-electrode 2b, and the thickness of the first sub-electrode 2a is smaller than or equal to 20nm.

In the embodiment of the present disclosure, the patterning of the first sub-electrode 2a is realized based on the characteristic that the adhesion between the first pattern 50 and the metal material is good, or the characteristic that the metal material cannot be attached on the second pattern 60. Compared with the related art, the method for patterning the film layer formed by the metal material in the etching manner can avoid the etching liquid from corroding other film layers and the ultraviolet light from adversely affecting other parts of the light-emitting element 2 in the exposure process.

Fig. 4 is a schematic flow chart of another method for manufacturing a display substrate according to an embodiment of the present disclosure, where the method is used to manufacture the display substrate shown in fig. 1a, and fig. 5a to 5d are schematic cross-sectional views of intermediate products manufactured by using the manufacturing method shown in fig. 4.

After step S1, the method for manufacturing a display substrate further includes:

step S11: as shown in fig. 5a, a driving functional layer 8 and a planarizing layer 9 are sequentially formed on a substrate 1.

The driving functional layer 8 includes a plurality of driving circuits configured to provide driving signals to the corresponding light emitting elements 2.

The step S2 may specifically include: step S21 to step S25.

Wherein, step S21: as shown in fig. 5a, the first electrode 21 of the light emitting element 2, the pixel defining layer 4, and the light emitting function layer 22 of the light emitting element 2 are sequentially formed on the planarization layer 9.

The driving circuit includes at least a driving transistor, and the first electrode 21 of the light emitting element 2 is electrically connected to the drain electrode of the driving transistor in the corresponding driving circuit through a corresponding via hole on the planarization layer 9.

Specifically, the step of forming the light emitting function layer 22 may include: a hole injection layer, a hole transport layer, an electron blocking layer, an organic light emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer are sequentially formed on the first electrode 21 by vapor deposition.

The pixel defining layer 4 has a plurality of pixel openings corresponding to the light emitting elements 2 one by one, and a portion of the light emitting elements 2 is located in the corresponding pixel opening. Specifically, the front projection areas of the first electrode 21 and the light-emitting functional layer 22 of the light-emitting element 2 on the substrate 1 are respectively larger than the front projection areas of the bottoms of the corresponding pixel openings on the pixel defining layer 4 on the substrate 1.

Step S22: as shown in fig. 5a, a first functional layer 5 is formed on a side of the light emitting functional layer 22 remote from the substrate 1, the first functional layer 5 including a plurality of first patterns 50.

The first pattern 50 is configured to promote the formation of the first metal material on a side surface of the first pattern 50 remote from the substrate 1.

In one example, the first functional layer 5 may be formed by a process of evaporation, printing, or sputtering.

Step S23: as shown in fig. 5b, the first sub-electrode 2a is formed on the first functional layer 5.

And forming a first metal material on one side of the first functional layer far away from the substrate through a metal evaporation process to obtain a plurality of first sub-electrodes corresponding to the first patterns one by one, wherein the orthographic projection of the first patterns on the substrate overlaps with the orthographic projection of the corresponding first sub-electrodes on the substrate. It should be noted that, the first functional layer 5 is configured to improve the adhesion of the metal material, and promote the formation of the first metal material on the surface of the first pattern 50 away from the substrate 1, so that in the process of forming the first sub-electrode 2a by using the vapor deposition metal process, the first functional layer 5 is equivalent to the mask, and no additional mask is required.

In some embodiments, the orthographic projection of the first sub-electrode 2a on the substrate 1 covers the orthographic projection of the bottom of the corresponding pixel opening on the substrate 1.

In some embodiments, as shown in fig. 1b, the front projection of the first sub-electrode on the substrate covers the front projection of the corresponding first pattern 50 on the substrate, and the distance between the edge of the first sub-electrode 2a and the edge on the same side on the corresponding first pattern 50 in the direction parallel to the substrate is less than or equal to 10 μm. That is, the first sub-electrode completely covers the first pattern, and a portion of the first sub-electrode beyond the first pattern does not exceed 10 μm, for example, 2 μm, 5 μm, 7 μm, etc.

In one example, the first sub-electrode includes a portion (i.e., a slope portion) having a gradually thinner thickness in a direction away from the first pattern at a portion beyond the first pattern. As shown in fig. 1b, the slope angle α1 at which the first sub-electrode located on the light emitting functional layer exceeds the edge of the first pattern portion is 45 ° or less, for example, 15 °, 30 °, or the like.

Step S24: as shown in fig. 5c, a light extraction pattern 3 is formed on the first sub-electrode 2 a.

The front projection area of the first sub-electrode 2a on the substrate 1 is larger than the front projection area of the corresponding light extraction pattern 3 on the substrate 1, and the front projection of the light extraction pattern 3 on the substrate 1 covers the front projection of the bottom of the corresponding pixel opening on the substrate 1.

Preferably, the light extraction pattern 3 is formed on the first sub-electrode 2a by an evaporation process.

Step S25: as shown in fig. 5d, the second sub-electrode 2b is formed on the light extraction pattern 3.

The second sub-electrode 2b is connected in parallel with the first sub-electrode 2a, and all the light emitting elements 2 share one second sub-electrode 2b.

Preferably, the second sub-electrode 2b is formed on the light extraction pattern 3 by a sputtering process.

After forming the light emitting element 2, the manufacturing method of the display substrate further includes step S3: an encapsulation layer 7 is formed on the second sub-electrode 2b to form a display substrate as shown in fig. 1 a. Wherein, the encapsulation layer 7 can prevent the corrosion and damage of the water oxygen to the light-emitting element 2, and prolong the service life of the device.

Fig. 6 is a schematic flow chart of another method for manufacturing a display substrate according to an embodiment of the present disclosure, where the method is used to manufacture the display substrate shown in fig. 2a, and fig. 7a to 7d are schematic cross-sectional views of intermediate products manufactured by using the manufacturing method shown in fig. 6.

Wherein, the formation process of the substrate 1 and the formation of the driving function layer 8, the planarization layer 9, the first electrode 21 of the light emitting element 2, the pixel defining layer 4 and the light emitting function layer 22 on the substrate 1 in sequence may be provided, reference may be made to the preparation method step S1, step S11 and step S21 of the display substrate in fig. 4, and the preparation method of the display substrate further includes:

Step S22': as shown in fig. 7a, a second functional layer 6 is formed on the side of the light emitting functional layer 22 remote from the substrate 1, the second functional layer 6 including a second pattern 60.

The second pattern 60 is formed with a plurality of hollow areas corresponding to the first sub-electrodes to be formed subsequently one by one; the second pattern 60 is configured to repel the first metal material.

Step S23': as shown in fig. 7b, the first sub-electrode 2a is formed at a position where the light emitting function layer 22 is away from the substrate 1 and the second function layer 6 is not formed.

The first metal material may be formed on a side of the second functional layer 6 remote from the substrate by an evaporation metal process, wherein the first metal material is formed in a region where the second pattern 60 is not provided to form the first sub-electrode 2a. Similarly to the first functional layer 5, the second functional layer 6 is configured to repel the first metal material to prevent the first metal material from being formed on a side surface of the second pattern 60 away from the substrate 1. Therefore, in the process of forming the first sub-electrode 2a by using the vapor deposition metal process, the second functional layer 6 is equivalent to the effect of the mask plate, and no mask plate is required to be additionally configured.

In some embodiments, as shown in fig. 2b, the first sub-electrode 2a is located on a side of the light-emitting functional layer away from the substrate and is located in the corresponding hollowed-out region, that is, the front projection of the first sub-electrode 2a on the substrate overlaps with the front projection of the corresponding hollowed-out region on the substrate. In some embodiments, the orthographic projection of the first sub-electrode 2a on the substrate 1 covers the orthographic projection of the corresponding hollowed-out area on the substrate 1; the distance between the edge of the first sub-electrode 2a and the edge on the same side of the corresponding hollowed-out area in the direction parallel to the substrate 1 is less than or equal to 15 μm. That is, the edge of the first sub-electrode extends above the second pattern, and the portion covering the second pattern is 15 μm or less, for example, 2 μm, 5 μm, 7 μm, or the like.

In one example, the portion of the first sub-electrode 2a covering the second pattern includes a portion (i.e., a slope portion) that is gradually thinner in a direction away from the corresponding hollowed-out region. As shown in fig. 2b, the slope angle α2 at the edge of the first sub-electrode on the second pattern is 45 ° or less, e.g., 15 °, 30 °, etc

It should be understood that, in the process of sequentially forming the light extraction pattern 3, the second sub-electrode 2b and the encapsulation layer 7 on the basis of the intermediate product of the display substrate shown in fig. 7b, reference may be made to step S24, step S25, step S3 and fig. 7c and 7d in fig. 4, and the display substrate shown in fig. 2a is finally formed, which is not repeated in the embodiment of the present disclosure.

In addition, in the method for manufacturing the display substrate, the materials, thicknesses, forming positions, and the like of the film layers are described in detail in the above embodiments, and are not described herein again.

The embodiment of the disclosure also provides a display device, which comprises the display substrate.

The display device may be: any product or component with a display function, such as electronic paper, mobile phone, tablet computer, television, display, notebook computer, digital photo frame, navigator, etc., which is not limited in this disclosure.

It is to be understood that the above embodiments are merely exemplary embodiments employed to illustrate the principles of the present disclosure, however, the present disclosure is not limited thereto. Various modifications and improvements may be made by those skilled in the art without departing from the spirit and substance of the disclosure, and are also considered to be within the scope of the disclosure.

Claims

1. A display substrate, comprising:

a substrate;

2. The display substrate of claim 1, wherein the first sub-electrode is a metal electrode and the second sub-electrode is a transparent electrode.

3. The display substrate according to claim 1, wherein the first sub-electrodes are in one-to-one correspondence with the light emitting elements, and the first sub-electrodes in different light emitting elements are arranged at intervals;

all of the light emitting elements share the same second sub-electrode.

4. A display substrate according to claim 3, wherein the light emitting element further comprises: a light extraction pattern located between and in contact with the first sub-electrode and the second sub-electrode;

5. The display substrate of claim 4, wherein the orthographic projection of the first sub-electrode on the base covers the orthographic projection of the corresponding light extraction pattern on the base.

6. The display substrate of claim 4, further comprising:

7. The display substrate of claim 1, wherein the material of the first sub-electrode comprises a first metal material;

8. The display substrate according to claim 7, wherein the orthographic projection of the first sub-electrode on the base covers the orthographic projection of the corresponding first pattern on the base, and a distance between an edge of the first sub-electrode and an edge on the same side corresponding to the first pattern in a direction parallel to the base is 10 μm or less.

9. The display substrate of claim 7, wherein a ratio of an area of orthographic projection of the first pattern on the base to an area of orthographic projection of the corresponding first sub-electrode on the base is between 0.9-1.1.

10. The display substrate of claim 1, wherein the material of the first sub-electrode comprises a first metal material;

11. The display substrate according to claim 10, wherein the orthographic projection of the first sub-electrode on the base covers the orthographic projection of the corresponding hollowed-out area on the base;

12. The display substrate according to claim 10, wherein the orthographic projection of the second pattern on the base overlaps with orthographic projections of the light emitting functional layers corresponding to at least two of the light emitting elements on the base.

13. The display substrate of claim 10, wherein the display substrate further comprises:

14. The display substrate according to claim 10, wherein a width ratio in the first direction of the first sub-electrode and the second pattern is between 1:9 and 9:1 at a portion of the first sub-electrode located on one side of the first sub-electrode in the first direction and adjacent to the first sub-electrode.

15. The display substrate of any one of claims 1 to 14, wherein a thickness of the first sub-electrode is less than a thickness of the second sub-electrode.

16. The display substrate of any one of claims 1 to 14, wherein the orthographic projection of the portion of the first sub-electrode on the base does not overlap with the orthographic projection of the corresponding first electrode on the base.

17. The display substrate according to any one of claims 1 to 14, wherein the orthographic projection area of the light emitting functional layer on the base is larger than the orthographic projection area of the corresponding first sub-electrode on the base.

18. The display substrate according to any one of claims 1 to 14, wherein the display substrate further comprises: an encapsulation layer and a driving function layer, wherein,

19. A display device, comprising: a display substrate according to any one of claims 1 to 18.

20. A method of manufacturing the display substrate according to any one of claims 1 to 18, comprising:

providing a substrate;

21. The method of manufacturing according to claim 20, wherein the display substrate is the display substrate of claim 7;

the step of forming the light emitting element includes: a step of forming a first electrode, a step of forming a light emitting functional layer, and a step of forming a second electrode;

wherein the step of forming the second electrode includes:

22. The method of manufacturing according to claim 21, wherein the display substrate is the display substrate of claim 10;

wherein the step of forming the second electrode includes: