CN113571545A - Display device and manufacturing method thereof - Google Patents

Abstract

The invention discloses a display device and a manufacturing method thereof, wherein the display device comprises: the light-emitting device comprises a substrate base plate, a light-emitting device and a pixel defining layer; the pixel definition layer comprises a first definition layer and a second definition layer which are arranged in a laminated mode, the first definition layer comprises a first through hole, the second definition layer comprises a second through hole, the first through hole and the second through hole are in the same position and are in one-to-one correspondence, the cross section area of the first through hole, which is parallel to the substrate base plate, is gradually reduced along the direction away from the substrate base plate, spreading of printing ink in a pit structure is facilitated, and short circuit of a device caused by direct contact of a top electrode and an exposed bottom electrode when the top electrode is formed is avoided. The sectional area of the second through hole parallel to the substrate base plate is gradually increased along the direction far away from the substrate base plate, and when the top electrode is formed, the top electrode fracture caused by the over-sharp opening of the second defining layer can be avoided, so that the open circuit problem when the top electrode is formed can be avoided, and the good conductivity of the top electrode is ensured.

Description

Display device and manufacturing method thereof

Technical Field

The invention relates to the technical field of display, in particular to a display device and a manufacturing method thereof.

Background

An Organic Light Emitting Diode (OLED) has the advantages of low power consumption, fast response speed, wide viewing angle, being lighter and thinner, and having flexibility, and is a display technology with great potential.

Quantum Dot Light Emitting Diodes (QLEDs) are manufactured by using Quantum dots as a Light Emitting layer, and the Light Emitting layer is introduced between different conductive materials to obtain Light with a required wavelength. The QLED has the advantages of wide color gamut, self-luminescence, low starting voltage, high response speed, long service life and the like.

The OLED and the QLED have similar structures, and a pixel defining layer for defining an area where a pixel is located needs to be formed when a display panel is manufactured, and at present, in order to match with a printing process with high efficiency, a cross-sectional pattern of the pixel defining layer between two pixels is generally set to be an inverted trapezoid, and such a pixel defining layer structure easily causes a metal electrode to be broken when a top metal electrode is prepared, resulting in a problem of poor conductivity, even disconnection.

Disclosure of Invention

In some embodiments of the present invention, the pixel defining layer includes a first defining layer and a second defining layer which are stacked, the first defining layer includes a first through hole, the second defining layer includes a second through hole, the positions of the first through hole and the second through hole are the same and are in one-to-one correspondence, the area of the cross section of the first through hole parallel to the substrate is gradually reduced along the direction away from the substrate, the cross section of the first defining layer presents an inverted trapezoid structure, the sidewall of the first defining layer is inclined toward the pit structure, which is beneficial to spreading of printing ink in the pit structure, so that the edge position of the pit structure is covered by the printing ink, and the bottom electrode is prevented from being exposed, and thus, when the top electrode is formed, the top electrode is prevented from being directly contacted with the exposed bottom electrode to cause short circuit of the device. The cross sectional area that the second through-hole is on a parallel with the substrate base plate is crescent along the direction of keeping away from the substrate base plate, and the cross-section of second definition layer presents regular trapezium structure, and its opening edge that deviates from substrate base plate one side is gentle obtuse angle structure, so when forming the top electrode, can avoid the second to define the top electrode fracture that the layer opening is too sharp and leads to, thereby can avoid the open circuit problem when forming the top electrode, guarantee the good electric conductivity of top electrode.

In some embodiments of the present invention, a size of an opening of a side of the first through hole of the first defining layer facing away from the substrate base is equal to a size of a side of the second through hole of the second defining layer facing towards the substrate base, and the first through hole and the second through hole are connected with each other, so that a cross section of an area where the sub-pixel defined by the pixel defining layer is located tends to decrease first and then increase along a direction away from the substrate base.

In some embodiments of the present invention, the inclination angles of the sidewalls of the first defining layer 131 and the second defining layer are greater than 45 ° and less than 70 °, so as to avoid that the inclination angles of the sidewalls of the pixel defining layer occupy the opening area of the sub-pixel unit too much.

In some embodiments of the present invention, the thickness of the first defining layer is less than the thickness of the second defining layer, the thickness of the first defining layer 131 is 100nm-200 nm; the thickness of the second defining layer 132 is 1 μm-2 μm. The thickness of the second defining layer is relatively large, which is beneficial to limiting the material of the light emitting layer or the functional layer in the range of the through hole.

In some embodiments of the present invention, the first defining layer and the second defining layer can be made of a photoresist material, and the photoresist is used to make the pattern of the pixel defining layer by using an exposure etching process of the photoresist.

In some embodiments of the present invention, the first defining layer and the second defining layer can be made of a positive photoresist, which has low cost, looser control of process accuracy, such as exposure time and developing time, and low process complexity.

In some embodiments of the present invention, the first and second defining layers can be fabricated using a negative photoresist, which is thermally and chemically stable.

In some embodiments of the present invention, the first defining layer and the second defining layer are made of mutually insoluble photoresist materials, so as to avoid the influence on the first defining layer when the second defining layer is made.

In some embodiments of the present invention, the first defining layer is a water-soluble polymer photoresist and the second defining layer is an organic solvent photoresist. The water-soluble polymer photoresist may be used to treat the surface of the substrate during the formation of the first defining layer to facilitate the application of the first defining layer. The requirement on the interface is not high when the second defining layer is made of the organic solvent photoresist, and the second defining layer is easier to coat.

In some embodiments of the present invention, a method for manufacturing a display device includes:

forming a pattern of a bottom electrode on a substrate base plate;

forming a first definition layer at spaced locations of the bottom electrode, the first definition layer including a first via for exposing the bottom electrode;

forming a second defining layer on the first defining layer, the second defining layer including a second via hole for exposing a bottom electrode;

forming a light emitting layer on the bottom electrodes of the first and second via holes;

forming a top electrode on the light emitting layer and the second defining layer;

the first through holes and the second through holes correspond to each other one by one and are in the same position; the cross-sectional area of the first through hole parallel to the substrate base plate is gradually reduced along the direction far away from the substrate base plate; the cross-sectional area of the second through hole parallel to the substrate base plate is gradually increased along the direction far away from the substrate base plate.

In some embodiments of the present invention, the forming a first defining layer at the spaced position of the bottom electrode comprises:

forming a first positive photoresist layer on the bottom electrode and the substrate base plate;

arranging a first mask plate on the first positive photoresist layer, and exposing the first mask plate; the light transmission area of the first mask plate corresponds to the position of the bottom electrode, and a negative lens is arranged in the light transmission area of the first mask plate;

developing the exposed first positive photoresist layer to form a first defining layer including the first through hole;

the forming a second defining layer on the first defining layer, comprising:

forming a second positive photoresist layer on the bottom electrode and the first defining layer;

arranging a second mask plate on the second positive photoresist layer, and exposing the second mask plate; the light transmission area of the second mask plate corresponds to the position of the bottom electrode, and a positive lens is arranged in the light transmission area of the second mask plate;

and developing the exposed second positive photoresist layer to form a second defining layer comprising the second through hole.

In some embodiments of the present invention, the forming a first defining layer at the spaced position of the bottom electrode comprises:

forming a first negative photoresist layer on the bottom electrode and the substrate base plate;

arranging a first mask plate on the first negative photoresist layer, and exposing the first mask plate; the shading area of the first mask plate corresponds to the position of the bottom electrode, and the light transmitting area of the first mask plate is provided with a positive lens;

developing the exposed first negative photoresist layer to form a first defining layer comprising the first through hole;

the forming a second defining layer on the first defining layer, comprising:

forming a second negative photoresist layer on the bottom electrode and the first defining layer;

arranging a second mask plate on the second negative photoresist layer, and exposing the second mask plate; the shading area of the second mask plate corresponds to the position of the bottom electrode, and a negative lens is arranged in the light transmitting area of the second mask plate;

and developing the exposed second negative photoresist layer to form a second defining layer comprising the second through hole.

In some embodiments of the present invention, the forming a first defining layer at the spaced position of the bottom electrode comprises:

forming a first positive photoresist layer on the bottom electrode and the substrate base plate;

arranging a first mask plate on the first positive photoresist layer, and exposing the first mask plate; the light transmission area of the first mask plate corresponds to the position of the bottom electrode, and a negative lens is arranged in the light transmission area of the first mask plate;

developing the exposed first positive photoresist layer to form a first defining layer including the first through hole;

the forming a second defining layer on the first defining layer, comprising:

forming a second negative photoresist layer on the bottom electrode and the first defining layer;

arranging a second mask plate on the second negative photoresist layer, and exposing the second mask plate; the shading area of the second mask plate corresponds to the position of the bottom electrode, and a negative lens is arranged in the light transmitting area of the second mask plate;

developing the exposed second negative photoresist layer to form a second defining layer comprising the second through hole;

alternatively, the first and second electrodes may be,

the forming of a first definition layer at spaced locations of the bottom electrode comprises:

forming a first negative photoresist layer on the bottom electrode and the substrate base plate;

arranging a first mask plate on the first negative photoresist layer, and exposing the first mask plate; the shading area of the first mask plate corresponds to the position of the bottom electrode, and the light transmitting area of the first mask plate is provided with a positive lens;

developing the exposed first negative photoresist layer to form a first defining layer comprising the first through hole;

the forming a second defining layer on the first defining layer, comprising:

forming a second positive photoresist layer on the bottom electrode and the first defining layer;

arranging a second mask plate on the second positive photoresist layer, and exposing the second mask plate; the light transmission area of the second mask plate corresponds to the position of the bottom electrode, and a positive lens is arranged in the light transmission area of the second mask plate;

and developing the exposed second positive photoresist layer to form a second defining layer comprising the second through hole.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic cross-sectional structure diagram of a display device according to an embodiment of the present invention;

fig. 2 is a flowchart of a method for manufacturing a display device according to an embodiment of the invention;

FIGS. 3a-3f are schematic structural diagrams corresponding to steps for fabricating a pixel defining layer according to an embodiment of the invention;

fig. 4a-4f are schematic structural diagrams corresponding to the steps of fabricating a pixel defining layer according to another embodiment of the invention.

The light-emitting device comprises a substrate 11, a substrate 12, a light-emitting device 13, a pixel defining layer 121, a bottom electrode 122, a top electrode 123, a light-emitting layer 131, a first defining layer 132, a second defining layer a1, a2, a second through hole 31, a first positive photoresist layer 32, a second positive photoresist layer 31 ', a first negative photoresist layer 32 ', a second negative photoresist layer 32 ', a first mask M1, a first mask M1 ', a second mask M2 and a second mask M2 '.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, the present invention is further described with reference to the accompanying drawings and examples. Example embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus their repetitive description will be omitted. The words expressing the position and direction described in the present invention are illustrated in the accompanying drawings, but may be changed as required and still be within the scope of the present invention. The drawings of the present invention are for illustrative purposes only and do not represent true scale.

As a new generation of Display technology, OLEDs have a smaller screen thickness and lighter weight than Liquid Crystal Displays (LCDs). The OLED screen also has a wide viewing angle which is not possessed by the LCD, so that an ultra-large visual range can be realized, and the picture can not be distorted. The response speed is one thousandth of that of the LCD screen. And the OLED screen is low temperature resistant, can normally display content at the temperature of-40 ℃, has higher luminous efficiency, low energy consumption and ecological environmental protection, can be manufactured into a curved screen, and brings visual impact with different feelings to viewers.

The quantum dot luminescent material has the characteristics of adjustable luminescent spectrum, high luminescent color purity, good photochemical stability and thermal stability and the like, and is widely applied to the field of novel display at present. Compared with OLED, the QLED using quantum dot material as luminescent material has the characteristics of wider color gamut, higher color rendering index, better solution processing performance and the like, so that the QLED has a very great application prospect in the display field.

The display device in the OLED display panel is an OLED, the display device in the QLED display panel is a QLED, and the structures of the OLED and the QLED are substantially the same, except that the light-emitting material in the OLED is an organic light-emitting material, and the light-emitting material in the QLED is a quantum dot light-emitting material.

The OLED display panel and the QLED display panel can be manufactured by adopting a printing process, the printing process is a key technology for large-area flat panel display application, and the printing process has the advantages of high material utilization rate, low cost and the like and is suitable for manufacturing large-area display panels.

Fig. 1 is a schematic cross-sectional structure diagram of a display device according to an embodiment of the present invention.

Referring to fig. 1, a display device according to an embodiment of the present invention includes: a substrate 11, a light emitting device 12, and a pixel defining layer 13.

The substrate 11 is located at the bottom of the display device and has supporting and bearing functions. The substrate base plate 11 is generally a rectangular structure including a top side, a bottom side, a left side, and a right side. Wherein the antenna side is opposite to the ground side, the left side is opposite to the right side, the antenna side is connected with one end of the left side and one side of the right side respectively, and the ground side is connected with the other end of the left side and the other end of the right side respectively.

The substrate 11 may be made of a rigid material or a flexible material. When the material 11 of the substrate base plate is made of hard material such as glass, the hard display device can be manufactured; when the substrate 11 is made of a flexible material such as Polyimide (PI), a flexible display device can be manufactured.

A driving line is formed on the substrate 11, the driving line is composed of thin film transistors, capacitors, resistors, and the like, a planarization layer is formed on the driving line layer, the planarization layer has a via hole for electrically connecting an electrode of the light emitting device with the driving line, and driving display of the light emitting device is realized by applying a driving signal to the driving line.

The light emitting device 12 is located on the substrate base plate, and in the embodiment of the present invention, the light emitting device 12 functions as a sub-pixel unit for image display.

Referring to fig. 1, the light emitting device 12 may include: a bottom electrode 121 on a side close to the substrate base plate 11, a top electrode 122 disposed opposite to the bottom electrode 121, and a light emitting layer 123 between the bottom electrode 121 and the top electrode 122.

The bottom electrodes 121 are discrete structures, and each bottom electrode 121 defines a light emitting device, i.e., a region where one sub-pixel unit is located. The driving lines on the substrate are electrically connected to the bottom electrodes 121 through the via holes, and a driving signal of the driving lines may be applied to each of the bottom electrodes 121.

The bottom electrode 121 is generally formed as an anode using a material such as Indium Tin Oxide (ITO).

In the embodiment of the present invention, after the bottom electrodes 121 are formed, the pixel defining layer 13 is formed on the substrate, and the pixel defining layer 13 may space the regions where the bottom electrodes 121 are located from each other, so as to define the position where each light emitting device, i.e., the sub-pixel unit, is located.

The pixel defining layer 13 has a larger thickness, a plurality of pit structures are formed at positions where the bottom electrodes 121 are located, the light emitting layer 123 is formed in the pit structures, an area where each pit structure is located is a sub-pixel unit, adjacent sub-pixel units display different colors, and accordingly, the light emitting layer 123 can be made of light emitting materials emitting different colors of light.

In the embodiment of the present invention, the light emitting device 12 may be an OLED or a QLED. When the light emitting device 12 is an OLED, the display device is an OLED display device, and the light emitting layer 123 is made of an organic light emitting material; when the light emitting device 12 is a QLED, the display device is a QLED display device, and the light emitting layer 123 is made of a quantum dot light emitting material.

The top electrode 122 is a top layer structure of the light emitting device 12, and the top electrode 122 is disposed in a whole layer covering the pit structure and the surface of the pixel defining layer 13.

The top electrode 122 is generally made of a material such as metallic silver (Ag) as a cathode.

In addition to this, the light emitting device 12 further includes functional layers for optimizing the device, such as a hole injection layer and a hole transport layer between the bottom electrode 121 and the light emitting layer 123, an electron transport layer between the light emitting layer 123 and the top electrode, and the like.

The light emitting layer 123 and the functional layer in the embodiment of the present invention may be manufactured by using a printing process such as inkjet printing.

Referring to fig. 1, in the embodiment of the present invention, the pixel defining layer 13 includes: a first defining layer 131 and a second defining layer 132 which are arranged in a stack.

The first delimiting layer 131 is positioned over the base substrate 11, and the first delimiting layer 131 includes a first via a1 for defining the light emitting device 12.

The second delimiting layer 132 is located on a surface of the first delimiting layer 131 on a side facing away from the substrate base plate 11, and the second delimiting layer 132 includes a second through hole a2 for defining the light emitting device 12.

The first through holes a1 and the second through holes a2 are in one-to-one correspondence and have the same position, and the first through holes a1 and the second through holes a2 are communicated with each other to form the pit structure of the pixel defining layer.

Referring to fig. 1, in the embodiment of the present invention, the first through-hole a1 is gradually reduced in the direction away from the base substrate 11 in parallel with the cross-sectional area of the base substrate 11; the second through hole a2 gradually increases in cross-sectional area parallel to the base substrate 11 in a direction away from the base substrate 11.

Since the section of the first through-holes a1 parallel to the base substrate 11 has a tendency to gradually decrease in a direction away from the base substrate 11, the first definition layer 131 between the adjacent first through-holes a1 exhibits an inverted trapezoidal structure in a section perpendicular to the base substrate 11.

When the light emitting layer 123 and the functional layer in the light emitting device 12 are manufactured by a printing process, the first defining layer 131 has an inverted trapezoidal structure, and the side wall of the first defining layer inclines towards the pit structure, so that the spreading of printing ink in the pit structure is facilitated, the edge position of the pit structure is covered by the printing ink, the bottom electrode 121 is prevented from being exposed, and the short circuit of the device caused by the direct contact of the top electrode and the exposed bottom electrode when the top electrode is formed can be avoided.

Since the section of the second through hole a2 parallel to the base substrate 11 has a tendency to gradually increase in a direction away from the base substrate 11, the second defining layer 132 between the adjacent second through holes a2 assumes an orthotrapezoidal structure in a section perpendicular to the base substrate 11.

The top electrode 122 is generally formed on the surfaces of the pit structure and the second defining layer 132 in a whole layer by evaporation, the second defining layer 132 is in a regular trapezoid structure, and the edge of the opening on the side of the second defining layer 132 away from the substrate 11 is in a gentle obtuse angle structure, so that when the top electrode 122 is formed, the top electrode can be prevented from being broken due to the fact that the opening of the second defining layer 132 is too sharp, the open circuit problem when the top electrode is formed can be avoided, and good conductivity of the top electrode 122 is ensured.

Referring to fig. 1, the opening size of the first through hole a1 on the side away from the base substrate 11 is equal to the opening size of the second through hole a2 on the side close to the base substrate 11. The opening edge of the first through hole a1 on the side away from the base substrate 11 and the opening edge of the second through hole a2 on the side close to the base substrate 11 coincide with each other, so that the sidewalls of the first and second defining layers 131 and 132 form a continuous surface.

In the embodiment of the present invention, the inclination angles of the sidewalls of the first defining layer 131 and the second defining layer 132 facing the pit structure are not too large, so as to avoid the pixel defining layer occupying the opening area of the sub-pixel unit. Typically, the first defining layer 131 and the second defining layer sidewall have an inclination angle of more than 45 ° and less than 70 °.

The thickness of the pixel defining layer 13 is in the micrometer scale, wherein the thickness of the first defining layer 131 is smaller than that of the second defining layer 132, the height of the first defining layer 131 is mainly used for forming the light emitting layer 123 and the functional layer, and the height of the second defining layer 132 is used for evaporating the top electrode.

In the embodiment of the present invention, the thickness of the first defining layer 131 is 100nm to 200 nm; the thickness of the second defining layer 132 is 1 μm-2 μm. The thickness of the second defining layer is relatively large, which is beneficial to limiting the material of the light emitting layer or the functional layer in the range of the through hole.

The pixel defining layer 13 may be formed of photoresist, and the through holes of the first interface layer 131 and the second defining layer 132 are formed by exposing and developing the photoresist. In the present embodiment, the first interface layer 131 is coated, exposed and developed to form a pattern of the first through hole a1, and the exposed and developed first interface layer 131 is cured; then, the second interface layer 132 is coated, exposed and developed to form a pattern of the second through holes a2, and the exposed and developed second interface layer 132 is cured, thereby completing the fabrication of the pixel defining layer 13.

The pixel defining layer 13 may be formed of either a positive or negative photoresist. Wherein, the first defining layer 131 and the second defining layer 132 can both adopt positive photoresist; alternatively, the first defining layer 131 and the second defining layer 132 may both be made of negative photoresist; alternatively, the first defining layer 131 uses a positive photoresist, and the second defining layer 132 uses a negative photoresist; alternatively, the first defining layer 131 uses a negative photoresist, and the second defining layer 132 uses a positive photoresist.

Positive photoresist is exposed such that the illuminated portions are soluble in a developer, while negative photoresist is exposed such that the non-illuminated portions are soluble in a developer. Therefore, the patterns formed by respectively exposing the positive photoresist and the negative photoresist by using the same mask plate are opposite. In practical application, the mask pattern can be designed according to the type of the adopted photoresist.

The first defining layer 131 and the second defining layer 132 are made of photoresist materials, and the second defining layer 132 is formed on the first defining layer 131. in order to avoid the influence on the first defining layer 131 when the second defining layer 132 is made, the first defining layer 131 and the second defining layer 132 are made of mutually incompatible photoresist materials.

In the embodiment of the present invention, the first defining layer 131 uses a water-soluble polymer photoresist, and the second defining layer 132 uses an organic solvent photoresist. The water-soluble polymer photoresist and the organic solvent photoresist are not soluble with each other, and the surface of the substrate can be processed when the water-soluble polymer photoresist is used for manufacturing the first defining layer 131, so that the first defining layer can be coated more easily. And the requirement on the interface is not high when the second defining layer is manufactured by adopting the organic solvent photoresist, so that the coating of the second defining layer is easier.

The following is a detailed description of a method for manufacturing the display device according to the embodiment of the present invention.

Fig. 2 is a flowchart of a method for manufacturing a display device according to an embodiment of the invention.

Referring to fig. 2, a method for manufacturing a display device according to an embodiment of the present invention includes:

s10, forming a bottom electrode pattern on the substrate;

s20, forming a first defining layer at the interval position of the bottom electrode, wherein the first defining layer comprises a first through hole for exposing the bottom electrode;

s30, forming a second defining layer on the first defining layer, the second defining layer including a second via hole for exposing the bottom electrode;

s40, forming a light-emitting layer on the bottom electrodes of the first through hole and the second through hole;

s50, forming a top electrode on the light-emitting layer and the second defining layer;

the bottom electrode, the light-emitting layer and the top electrode form a light-emitting device, and the light-emitting device can be an OLED or a QLED.

Specifically, after a bottom electrode is formed on a substrate, the substrate on which the bottom electrode is formed is cleaned, and after the substrate is cleaned and dried, a pixel defining layer is formed.

The pixel defining layer includes a first defining layer and a second defining layer. The whole photoresist material for forming the first defining layer is coated on the substrate base plate on which the bottom electrode is formed, and the photoresist layer is exposed and developed to form a first through hole for exposing the bottom electrode. And coating the whole photoresist material for forming the second defining layer on the exposed bottom electrode and the first defining layer, and exposing and developing the photoresist layer to form a second through hole for exposing the bottom electrode.

The first through hole and the second through hole are located at the same position, so that the first defining layer and the second defining layer form a pit structure for forming the light emitting device.

In the embodiment of the invention, the area of the cross section of the first through hole, which is parallel to the substrate base plate, is gradually reduced along the direction far away from the substrate base plate, the cross section of the first defining layer is in an inverted trapezoidal structure, the side wall of the first through hole is inclined towards the pit structure, so that the spreading of printing ink in the pit structure is facilitated, the edge position of the pit structure is covered by the printing ink, the bottom electrode is prevented from being exposed, and the short circuit of a device caused by the direct contact of the top electrode and the exposed bottom electrode when the top electrode is formed can be avoided.

The cross sectional area that the second through-hole is on a parallel with the substrate base plate is crescent along the direction of keeping away from the substrate base plate, and the cross-section of second definition layer presents regular trapezium structure, and its opening edge that deviates from substrate base plate one side is gentle obtuse angle structure, so when forming the top electrode, can avoid the second to define the top electrode fracture that the layer opening is too sharp and leads to, thereby can avoid the open circuit problem when forming the top electrode, guarantee the good electric conductivity of top electrode.

After the pixel defining layer is formed, the substrate is cleaned and dried, and then the light emitting layer and the functional layer are formed.

After the light emitting layer and the functional layer are manufactured, the top electrode is evaporated in a whole layer.

After the top electrode is manufactured, the display panel is subjected to subsequent operations such as packaging and testing, so that the display device is manufactured.

In the embodiment of the invention, the first defining layer and the second defining layer can be made of photoresist materials, and the making process is different when a positive photoresist material and a negative photoresist material are used.

Specifically, in the embodiment of the present invention, when the first defining layer and the second defining layer are both made of a positive photoresist material, reference is made to the schematic structural diagrams corresponding to the manufacturing steps shown in fig. 3a to 3 f.

Referring to fig. 3a, a first positive photoresist layer 31 is formed on the bottom electrode 121 and the base substrate 11.

The exposed portion of the positive photoresist may be dissolved in a developing solution, and thus the exposed portion corresponds to a position of the first via hole of the first defining layer.

Referring to fig. 3b, a first mask M1 is disposed over the first positive photoresist layer 31, and the first mask M1 is exposed.

Since the first defining layer is made of positive photoresist, the exposed photoresist can be dissolved in the developing solution, and is dissolved by the developing solution, and the unexposed portion is remained, and finally the first defining layer is formed, so that the light-transmitting region of the first mask M1 corresponds to the position of the bottom electrode 121, and the light-transmitting region of the first mask M1 is provided with a negative lens. The negative lens has a diverging effect on the incident light, and the light passing through the light transmitting region of the first mask M1 is diverging light, and the positive photoresist in the light propagation direction can be exposed after the diverging light is incident on the first positive photoresist layer 31.

Referring to fig. 3c, the exposed first positive photoresist layer is developed to form a first defining layer 131 including a first via a 1.

The exposed photoresist portion is used to form a first through hole a1, and after the first positive photoresist layer is exposed by using divergent light, the cross section of the exposed portion has a regular trapezoid structure, so that after the exposed first positive photoresist layer is developed, a first through hole a1 having a regular trapezoid structure can be formed, thereby completing the fabrication of the first defining layer 131.

Referring to fig. 3d, a second positive photoresist layer 32 is formed on the bottom electrode 121 and the first defining layer 131.

The exposed portion of the positive photoresist may be dissolved in a developing solution, and thus the exposed portion corresponds to a position of the second via hole of the first defining layer.

Referring to fig. 3e, a second mask M2 is disposed over the second positive photoresist layer 32, and the second mask M2 is exposed.

Since the second defining layer is made of positive photoresist, the exposed photoresist can be dissolved in the developing solution, and is dissolved by the developing solution, and the unexposed portion is remained, and finally the second defining layer is formed, so that the light-transmitting region of the second mask M2 corresponds to the position of the bottom electrode 121, and the light-transmitting region of the second mask M2 is provided with a positive lens. The positive lens has a converging effect on incident light, so that the light passing through the light transmitting region of the second mask M2 is converging light, and the converging light can be incident on the second positive photoresist layer 32 and then expose the positive photoresist in the light propagation direction.

Referring to fig. 3f, the exposed second positive photoresist layer is developed to form the second defining layer 132 including the second via a 2.

The exposed photoresist portion is used to form the second via a2, and after the second positive photoresist layer is exposed by the convergent light, the cross section of the exposed portion has an inverted trapezoidal structure, so that after the exposed second positive photoresist layer is developed, the second via a2 having an inverted trapezoidal structure can be formed, thereby completing the fabrication of the second defining layer 132.

Positive photoresist has lower cost, more relaxed control of process accuracy, such as exposure time and development time, and low process complexity.

In addition, when a positive photoresist material is adopted and no lens is arranged in the light transmitting area of the mask plate, a through hole with an inverted trapezoidal structure in section can be formed in the exposure area after exposure and development. The inclination degree of the side wall of the pixel definition layer depends on the divergence and convergence degree of the light, so that the side wall of the pixel definition layer can be adjusted to have a proper inclination angle by adjusting the focal length of the lens.

The lens on the mask plate can be arranged on one side facing the display panel and can also be arranged on one side departing from the display panel.

In another embodiment of the present invention, when the first defining layer and the second defining layer are both made of a negative photoresist material, reference is made to the structural diagrams corresponding to the manufacturing steps shown in fig. 4a to 4 f.

Referring to fig. 4a, a first negative photoresist layer 31' is formed on the bottom electrode 121 and the base substrate 11.

The exposed portions of the negative photoresist are cured and the unexposed portions are soluble in a developer, so that the exposed portions correspond to the locations of the first defining layer.

Referring to fig. 4b, a first mask M1 ' is disposed over the first negative photoresist layer 31 ', and the first mask M1 ' is exposed.

Because the first defining layer adopts negative photoresist, the exposed photoresist is cured, the unexposed photoresist can be dissolved in the developing solution, and is dissolved by the developing solution, and the exposed part is remained, and finally the first defining layer is formed, so that the light shielding area of the first mask plate M1 'corresponds to the position of the bottom electrode 121, and the light transmitting area of the first mask plate M1' is provided with a positive lens. The positive lens has a converging effect on incident light, so that the light passing through the light transmitting region of the first mask M1 'is converging light, and the converging light can be incident on the first negative photoresist layer 31' and then expose the negative photoresist in the light propagation direction.

Referring to fig. 4c, the exposed first negative photoresist layer is developed to form a first defining layer 131 including a first via a 1.

The exposed photoresist portion is used to form the first defining layer 131, and after the first negative photoresist layer is exposed by using convergent light, the cross section of the exposed portion has an inverted trapezoidal structure, so that after the exposed first negative photoresist layer is developed, the first defining layer 131 having the inverted trapezoidal structure may be formed, and the first through hole a1 having a regular trapezoidal structure may be formed, thereby completing the fabrication of the first defining layer 131.

Referring to fig. 4d, a second negative photoresist layer 32' is formed on the bottom electrode 121 and the first defining layer 131.

The exposed portions of the negative photoresist are cured and the unexposed portions are soluble in a developer, so that the exposed portions correspond to the locations of the second defining layer.

Referring to fig. 4e, a second mask M2 ' is disposed on the second negative photoresist layer 32 ', and the second mask M2 ' is exposed.

Because the second defining layer adopts negative photoresist, the exposed photoresist is cured, the unexposed photoresist can be dissolved in the developing solution, and is dissolved by the developing solution, and the exposed part is remained, and finally the second defining layer is formed, so that the light shielding area of the second mask plate M2 'corresponds to the position of the bottom electrode 121, and the light transmitting area of the second mask plate M2' is provided with a negative lens. The negative lens has a diverging effect on the incident light, and the light passing through the light transmitting region of the second mask M2 'is diverging light, and the negative photoresist in the light propagation direction can be exposed after the diverging light is incident on the second negative photoresist layer 32'.

Referring to fig. 4f, the exposed second negative photoresist layer is developed to form a second defining layer 132 including a second via a 2.

The exposed photoresist portion is used for forming the second defining layer 132, and after the second negative photoresist layer is exposed by using divergent light, the cross section of the exposed portion is in a forward and reverse trapezoidal structure, so that after the exposed second negative photoresist layer is developed, the second defining layer 132 with the forward and reverse trapezoidal structure can be formed, the second through hole a2 with the reverse trapezoidal structure is formed, and thus, the second defining layer 132 is manufactured.

Negative photoresist has excellent thermal and chemical stability and thus can be applied to a display device having specific requirements for a pixel defining layer.

In addition, when a negative photoresist material is adopted and no lens is arranged in the light transmitting area of the mask plate, a pixel defining layer structure with an inverted trapezoid-shaped cross section can be formed in the exposure area after exposure and development. The inclination degree of the side wall of the pixel definition layer depends on the divergence and convergence degree of the light, so that the side wall of the pixel definition layer can be adjusted to have a proper inclination angle by adjusting the focal length of the lens.

The lens on the mask plate can be arranged on one side facing the display panel and can also be arranged on one side departing from the display panel.

In another embodiment of the present invention, when the first defining layer is made of a positive photoresist material and the second defining layer is made of a negative photoresist material, the structural schematic diagrams corresponding to the making steps of the first defining layer refer to fig. 3a to 3c, and the structural schematic diagrams corresponding to the making steps of the second defining layer refer to fig. 4d to 4 f.

Referring to fig. 3a, a first positive photoresist layer 31 is formed on the bottom electrode 121 and the base substrate 11.

The exposed portion of the positive photoresist may be dissolved in a developing solution, and thus the exposed portion corresponds to a position of the first via hole of the first defining layer.

Referring to fig. 3b, a first mask M1 is disposed over the first positive photoresist layer 31, and the first mask M1 is exposed.

Since the first defining layer is made of positive photoresist, the exposed photoresist can be dissolved in the developing solution, and is dissolved by the developing solution, and the unexposed portion is remained, and finally the first defining layer is formed, so that the light-transmitting region of the first mask M1 corresponds to the position of the bottom electrode 121, and the light-transmitting region of the first mask M1 is provided with a negative lens. The negative lens has a diverging effect on the incident light, and the light passing through the light transmitting region of the first mask M1 is diverging light, and the positive photoresist in the light propagation direction can be exposed after the diverging light is incident on the first positive photoresist layer 31.

Referring to fig. 3c, the exposed first positive photoresist layer is developed to form a first defining layer 131 including a first via a 1.

The exposed photoresist portion is used to form a first through hole a1, and after the first positive photoresist layer is exposed by using divergent light, the cross section of the exposed portion has a regular trapezoid structure, so that after the exposed first positive photoresist layer is developed, a first through hole a1 having a regular trapezoid structure can be formed, thereby completing the fabrication of the first defining layer 131.

Referring to fig. 4d, a second negative photoresist layer 32' is formed on the bottom electrode 121 and the first defining layer 131.

The exposed portions of the negative photoresist are cured and the unexposed portions are soluble in a developer, so that the exposed portions correspond to the locations of the second defining layer.

Referring to fig. 4e, a second mask M2 ' is disposed on the second negative photoresist layer 32 ', and the second mask M2 ' is exposed.

Because the second defining layer adopts negative photoresist, the exposed photoresist is cured, the unexposed photoresist can be dissolved in the developing solution, and is dissolved by the developing solution, and the exposed part is remained, and finally the second defining layer is formed, so that the light shielding area of the second mask plate M2 'corresponds to the position of the bottom electrode 121, and the light transmitting area of the second mask plate M2' is provided with a negative lens. The negative lens has a diverging effect on the incident light, and the light passing through the light transmitting region of the second mask M2 'is diverging light, and the negative photoresist in the light propagation direction can be exposed after the diverging light is incident on the second negative photoresist layer 32'.

Referring to fig. 4f, the exposed second negative photoresist layer is developed to form a second defining layer 132 including a second via a 2.

The exposed photoresist portion is used for forming the second defining layer 132, and after the second negative photoresist layer is exposed by using divergent light, the cross section of the exposed portion is in a forward and reverse trapezoidal structure, so that after the exposed second negative photoresist layer is developed, the second defining layer 132 with the forward and reverse trapezoidal structure can be formed, the second through hole a2 with the reverse trapezoidal structure is formed, and thus, the second defining layer 132 is manufactured.

In another embodiment of the present invention, when the first defining layer is made of a negative photoresist material and the second defining layer is made of a positive photoresist material, the structural schematic diagrams corresponding to the making steps of the first defining layer refer to fig. 4a to 4c, and the structural schematic diagrams corresponding to the making steps of the second defining layer refer to fig. 3d to 3 f.

Referring to fig. 4a, a first negative photoresist layer 31' is formed on the bottom electrode 121 and the base substrate 11.

The exposed portions of the negative photoresist are cured and the unexposed portions are soluble in a developer, so that the exposed portions correspond to the locations of the first defining layer.

Referring to fig. 4b, a first mask M1 ' is disposed over the first negative photoresist layer 31 ', and the first mask M1 ' is exposed.

Because the first defining layer adopts negative photoresist, the exposed photoresist is cured, the unexposed photoresist can be dissolved in the developing solution, and is dissolved by the developing solution, and the exposed part is remained, and finally the first defining layer is formed, so that the light shielding area of the first mask plate M1 'corresponds to the position of the bottom electrode 121, and the light transmitting area of the first mask plate M1' is provided with a positive lens. The positive lens has a converging effect on incident light, so that the light passing through the light transmitting region of the first mask M1 'is converging light, and the converging light can be incident on the first negative photoresist layer 31' and then expose the negative photoresist in the light propagation direction.

Referring to fig. 4c, the exposed first negative photoresist layer is developed to form a first defining layer 131 including a first via a 1.

The exposed photoresist portion is used to form the first defining layer 131, and after the first negative photoresist layer is exposed by using convergent light, the cross section of the exposed portion has an inverted trapezoidal structure, so that after the exposed first negative photoresist layer is developed, the first defining layer 131 having the inverted trapezoidal structure may be formed, and the first through hole a1 having a regular trapezoidal structure may be formed, thereby completing the fabrication of the first defining layer 131.

Referring to fig. 3d, a second positive photoresist layer 32 is formed on the bottom electrode 121 and the first defining layer 131.

The exposed portion of the positive photoresist may be dissolved in a developing solution, and thus the exposed portion corresponds to a position of the second via hole of the first defining layer.

Referring to fig. 3e, a second mask M2 is disposed over the second positive photoresist layer 32, and the second mask M2 is exposed.

Since the second defining layer is made of positive photoresist, the exposed photoresist can be dissolved in the developing solution, and is dissolved by the developing solution, and the unexposed portion is remained, and finally the second defining layer is formed, so that the light-transmitting region of the second mask M2 corresponds to the position of the bottom electrode 121, and the light-transmitting region of the second mask M2 is provided with a positive lens. The positive lens has a converging effect on incident light, so that the light passing through the light transmitting region of the second mask M2 is converging light, and the converging light can be incident on the second positive photoresist layer 32 and then expose the positive photoresist in the light propagation direction.

Referring to fig. 3f, the exposed second positive photoresist layer is developed to form the second defining layer 132 including the second via a 2.

The exposed photoresist portion is used to form the second via a2, and after the second positive photoresist layer is exposed by the convergent light, the cross section of the exposed portion has an inverted trapezoidal structure, so that after the exposed second positive photoresist layer is developed, the second via a2 having an inverted trapezoidal structure can be formed, thereby completing the fabrication of the second defining layer 132.

According to the first invention concept, the pixel defining layer comprises a first defining layer and a second defining layer which are arranged in a laminated manner, the first defining layer comprises a first through hole, the second defining layer comprises a second through hole, the positions of the first through hole and the second through hole are the same and are in one-to-one correspondence, the area, parallel to the cross section of the substrate, of the first through hole is gradually reduced along the direction away from the substrate, the cross section of the first defining layer is in an inverted trapezoidal structure, the side wall of the first defining layer inclines towards the pit structure, spreading of printing ink in the pit structure is facilitated, the edge position of the pit structure is covered by the printing ink, and the bottom electrode is prevented from being exposed, so that when the top electrode is formed, the top electrode is directly contacted with the exposed bottom electrode to cause short circuit of a device. The cross sectional area that the second through-hole is on a parallel with the substrate base plate is crescent along the direction of keeping away from the substrate base plate, and the cross-section of second definition layer presents regular trapezium structure, and its opening edge that deviates from substrate base plate one side is gentle obtuse angle structure, so when forming the top electrode, can avoid the second to define the top electrode fracture that the layer opening is too sharp and leads to, thereby can avoid the open circuit problem when forming the top electrode, guarantee the good electric conductivity of top electrode.

According to the second inventive concept, the size of the opening of the first through hole of the first defining layer on the side away from the substrate base plate is equal to the size of the second through hole of the second defining layer on the side facing the substrate base plate, and the first through hole and the second through hole are connected with each other, so that the cross section of the area where the sub-pixel defined by the pixel defining layer is located tends to decrease first and then increase along the direction away from the substrate base plate.

According to the third inventive concept, the inclination angles of the sidewalls of the first and second defining layers 131 and 131 are greater than 45 ° and less than 70 °, so as to prevent the sidewalls of the pixel defining layers from excessively inclining to occupy the opening area of the sub-pixel unit.

According to the fourth inventive concept, the thickness of the first defining layer is less than that of the second defining layer, and the thickness of the first defining layer 131 is 100nm to 200 nm; the thickness of the second defining layer 132 is 1 μm-2 μm. The thickness of the second defining layer is relatively large, which is beneficial to limiting the material of the light emitting layer or the functional layer in the range of the through hole.

According to the fifth inventive concept, both the first defining layer and the second defining layer can be made of photoresist materials, and the photoresist is used for making the pattern of the pixel defining layer by using the exposure etching process of the photoresist.

According to the sixth inventive concept, the first defining layer and the second defining layer can be fabricated using a positive photoresist, which has a low cost, a looser control of process accuracy, such as exposure time and development time, and a low process complexity.

According to the seventh inventive concept, the first defining layer and the second defining layer can be fabricated using a negative photoresist, which has excellent thermal and chemical stability.

According to the eighth inventive concept, the first defining layer and the second defining layer are made of mutually insoluble photoresist materials, so that the first defining layer is prevented from being affected when the second defining layer is made.

According to the ninth inventive concept, the first defining layer uses a water-soluble polymer photoresist, and the second defining layer uses an organic solvent photoresist. The water-soluble polymer photoresist may be used to treat the surface of the substrate during the formation of the first defining layer to facilitate the application of the first defining layer. The requirement on the interface is not high when the second defining layer is made of the organic solvent photoresist, and the second defining layer is easier to coat.

According to the tenth inventive concept, when the first defining layer is made of a positive photoresist material, the light transmitting area of the mask plate used for exposing the photoresist layer of the first defining layer corresponds to the position of the first through hole, and the light transmitting area of the mask plate is provided with the negative lens. The negative lens has a divergence effect on incident light, the light passing through a light transmission area of the mask plate is divergent light, the divergent light enters the positive photoresist layer and can form a reverse trapezoidal first defining layer and a positive trapezoidal first through hole after being developed.

According to the eleventh invention, when the first defining layer is made of a negative photoresist material, the light-shielding region of the mask plate used for exposing the photoresist layer of the first defining layer corresponds to the position of the first through hole, and the light-transmitting region of the mask plate is provided with the positive lens. The positive lens has a convergence effect on incident light, the light passing through the light transmitting area of the mask plate is convergent light, the convergent light enters the negative photoresist layer and can form a reverse trapezoidal first defining layer and a forward trapezoidal first through hole after being developed.

According to the twelfth inventive concept, when the second defining layer is made of a positive photoresist material, the light transmitting area of the mask plate used for exposing the photoresist layer of the second defining layer corresponds to the position of the second through hole, and the light transmitting area of the mask plate is provided with a positive lens. The positive lens has a convergence effect on incident light, the light passing through the light transmitting area of the mask plate is convergent light, the convergent light enters the positive photoresist layer and can form a second regular trapezoid defining layer and a second inverse trapezoid through hole after being developed.

According to the thirteenth invention, when the second defining layer is made of a negative photoresist material, the light-shielding region of the mask plate used for exposing the photoresist layer of the second defining layer corresponds to the position of the second through hole, and the light-transmitting region of the mask plate is provided with a negative lens. The negative lens has a divergence effect on incident light, the light passing through the light transmitting area of the mask plate is divergent light, the divergent light enters the negative photoresist layer and can form a positive trapezoid second defining layer and a reverse trapezoid second through hole after being developed.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (10)

1. A display device, comprising:

a substrate base plate having a bearing function;

the light-emitting device is positioned on the substrate base plate and used for displaying images;

a pixel defining layer at spaced locations of the light emitting devices on the substrate base;

the pixel defining layer includes:

a first defining layer located over the substrate base plate; the first confinement layer includes a first via for defining a light emitting device;

a second defining layer located on a surface of the first defining layer on a side facing away from the substrate base plate; the second confinement layer includes a second via for defining a light emitting device;

the first through holes and the second through holes correspond to each other one by one and are in the same position;

the cross-sectional area of the first through hole parallel to the substrate base plate is gradually reduced along the direction far away from the substrate base plate; the cross-sectional area of the second through hole parallel to the substrate base plate is gradually increased along the direction far away from the substrate base plate.

2. The display device of claim 1, wherein an opening of the first via on a side facing away from the substrate base is equal in size to an opening of the second via on a side facing toward the substrate base.

3. The display device according to claim 1, wherein a thickness of the first defining layer is smaller than a thickness of the second defining layer;

the thickness of the first defining layer is 100nm-200 nm; the second defining layer has a thickness of 1-2 μm.

4. The display device according to claim 1, wherein the first defining layer and the second defining layer each employ a positive photoresist; alternatively, the first and second electrodes may be,

the first defining layer and the second defining layer both adopt negative photoresist; alternatively, the first and second electrodes may be,

the first defining layer adopts positive photoresist, and the second defining layer adopts negative photoresist; alternatively, the first and second electrodes may be,

the first defining layer adopts negative photoresist, and the second defining layer adopts positive photoresist.

5. The display device according to claim 4, wherein the first defining layer uses a water-soluble polymer photoresist, and the second defining layer uses an organic solvent photoresist.

6. The display apparatus of any one of claims 1-5, wherein the light emitting device is an organic light emitting diode or a quantum dot light emitting diode.

7. A method for manufacturing a display device, comprising:

forming a pattern of a bottom electrode on a substrate base plate;

forming a first definition layer at spaced locations of the bottom electrode, the first definition layer including a first via for exposing the bottom electrode;

forming a second defining layer on the first defining layer, the second defining layer including a second via hole for exposing a bottom electrode;

forming a light emitting layer on the bottom electrodes of the first and second via holes;

forming a top electrode on the light emitting layer and the second defining layer;

the first through holes and the second through holes correspond to each other one by one and are in the same position; the cross-sectional area of the first through hole parallel to the substrate base plate is gradually reduced along the direction far away from the substrate base plate; the cross-sectional area of the second through hole parallel to the substrate base plate is gradually increased along the direction far away from the substrate base plate.

8. The method of claim 7, wherein forming a first definition layer at spaced locations of the bottom electrode comprises:

forming a first positive photoresist layer on the bottom electrode and the substrate base plate;

arranging a first mask plate on the first positive photoresist layer, and exposing the first mask plate; the light transmission area of the first mask plate corresponds to the position of the bottom electrode, and a negative lens is arranged in the light transmission area of the first mask plate;

developing the exposed first positive photoresist layer to form a first defining layer including the first through hole;

the forming a second defining layer on the first defining layer, comprising:

forming a second positive photoresist layer on the bottom electrode and the first defining layer;

arranging a second mask plate on the second positive photoresist layer, and exposing the second mask plate; the light transmission area of the second mask plate corresponds to the position of the bottom electrode, and a positive lens is arranged in the light transmission area of the second mask plate;

and developing the exposed second positive photoresist layer to form a second defining layer comprising the second through hole.

9. The method of claim 7, wherein forming a first definition layer at spaced locations of the bottom electrode comprises:

forming a first negative photoresist layer on the bottom electrode and the substrate base plate;

arranging a first mask plate on the first negative photoresist layer, and exposing the first mask plate; the shading area of the first mask plate corresponds to the position of the bottom electrode, and the light transmitting area of the first mask plate is provided with a positive lens;

developing the exposed first negative photoresist layer to form a first defining layer comprising the first through hole;

the forming a second defining layer on the first defining layer, comprising:

forming a second negative photoresist layer on the bottom electrode and the first defining layer;

arranging a second mask plate on the second negative photoresist layer, and exposing the second mask plate; the shading area of the second mask plate corresponds to the position of the bottom electrode, and a negative lens is arranged in the light transmitting area of the second mask plate;

and developing the exposed second negative photoresist layer to form a second defining layer comprising the second through hole.

10. The method of claim 7, wherein forming a first definition layer at spaced locations of the bottom electrode comprises:

forming a first positive photoresist layer on the bottom electrode and the substrate base plate;

arranging a first mask plate on the first positive photoresist layer, and exposing the first mask plate; the light transmission area of the first mask plate corresponds to the position of the bottom electrode, and a negative lens is arranged in the light transmission area of the first mask plate;

developing the exposed first positive photoresist layer to form a first defining layer including the first through hole;

the forming a second defining layer on the first defining layer, comprising:

forming a second negative photoresist layer on the bottom electrode and the first defining layer;

arranging a second mask plate on the second negative photoresist layer, and exposing the second mask plate; the shading area of the second mask plate corresponds to the position of the bottom electrode, and a negative lens is arranged in the light transmitting area of the second mask plate;

developing the exposed second negative photoresist layer to form a second defining layer comprising the second through hole;

alternatively, the first and second electrodes may be,

the forming of a first definition layer at spaced locations of the bottom electrode comprises:

forming a first negative photoresist layer on the bottom electrode and the substrate base plate;

arranging a first mask plate on the first negative photoresist layer, and exposing the first mask plate; the shading area of the first mask plate corresponds to the position of the bottom electrode, and the light transmitting area of the first mask plate is provided with a positive lens;

developing the exposed first negative photoresist layer to form a first defining layer comprising the first through hole;

the forming a second defining layer on the first defining layer, comprising:

forming a second positive photoresist layer on the bottom electrode and the first defining layer;

arranging a second mask plate on the second positive photoresist layer, and exposing the second mask plate; the light transmission area of the second mask plate corresponds to the position of the bottom electrode, and a positive lens is arranged in the light transmission area of the second mask plate;

and developing the exposed second positive photoresist layer to form a second defining layer comprising the second through hole.

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