CN113571554A

CN113571554A - Display panel and preparation method thereof

Info

Publication number: CN113571554A
Application number: CN202110762149.3A
Authority: CN
Inventors: 李远航
Original assignee: Wuhan China Star Optoelectronics Semiconductor Display Technology Co Ltd
Current assignee: Wuhan China Star Optoelectronics Semiconductor Display Technology Co Ltd
Priority date: 2021-07-06
Filing date: 2021-07-06
Publication date: 2021-10-29

Abstract

A display panel and a method for manufacturing the same are provided. The display panel comprises a substrate base plate, a thin film transistor array layer, a pixel definition layer, a light-emitting device layer, a thin film packaging layer and a color resistance layer. The pixel defining layer is provided with an opening at a position corresponding to the anode; the color resistance layer is arranged in the thin film packaging layer and is positioned in the opening; wherein the pixel definition layer is opaque. The display panel reduces the distance between the light-emitting device layer and the color resistance layer, and further improves the transmittance, the visual angle and the bending performance of the display panel.

Description

Display panel and preparation method thereof

Technical Field

The application relates to the field of display, in particular to a display panel and a preparation method thereof.

Background

For an Organic Light-Emitting Diode (OLED) display panel, the polarizer can effectively reduce the reflectivity of the OLED display panel under strong Light, but the OLED display panel loses about 58% of the Light emission, which greatly increases the service life burden of the OLED display panel, and the polarizer has a thickness of about 100 μm, is thick and brittle, and is not favorable for the development of dynamic bending products.

In order to develop a dynamic bending product based on an OLED display panel, a non-polarizer (POL-less) technology is generally used to manufacture the OLED display panel, and the POL-less technology refers to a technology in which a Color Film (CF) is used to replace a polarizer. The color film is composed of a red color resistor, a green color resistor, a blue color resistor and a Black Matrix (BM), wherein in the OLED display panel, the red color resistor, the green color resistor and the blue color resistor respectively play roles in emitting light of the red sub-pixel unit, the green sub-pixel unit and the blue sub-pixel unit, and the Black Matrix mainly plays roles in preventing light leakage of the OLED display panel and reducing the reflectivity of the OLED display panel. The color film can reduce the reflectivity of the OLED display panel under strong light to a certain extent, can improve the light-emitting rate of the OLED display panel from 42% to 60%, has the thickness of about 5 microns, is much smaller than that of the polarizer, has high flexibility, can reduce the overall thickness of the OLED display panel, and is favorable for development of dynamic bending products.

The POL-less technology is mainly to form the color film on the thin film encapsulation layer by the yellow light process, however, the yellow light process is complicated and the yield is low, and the thin film encapsulation layer causes the large distance (more than 10 μm) between the BM opening and the OLED pixel, which leads to the problems of the small visible angle of the panel and the unable to further increase the transmittance.

Disclosure of Invention

An object of the present application is to provide a display panel and a manufacturing method thereof, for solving the technical problems in the prior art that a color film is formed on a film encapsulation layer by a yellow light process, so that the process is complicated, the yield is low, the visible angle is reduced, and the transmittance cannot be further improved.

In order to solve the above problems, the present application provides a display panel including: a substrate base plate;

a thin film transistor array layer disposed on the substrate base plate; an anode disposed on the thin film transistor array layer; the pixel defining layer covers the thin film transistor array layer and is provided with an opening at a position corresponding to the anode; a light emitting device layer disposed within the opening; a thin film encapsulation layer covering the pixel defining layer and the light emitting device layer; the color resistance layer is arranged in the thin film packaging layer and is positioned in the opening; wherein the pixel definition layer is opaque.

In some embodiments, the thin film encapsulation layer comprises: a first inorganic layer covering the pixel defining layer and the light emitting device layer; the organic flat layer covers the first inorganic layer and the color resistance layer; and a second inorganic layer overlying the organic planarization layer; wherein the color-resist layer is disposed on the first inorganic layer and within the opening.

In some embodiments, the sidewalls of the pixel definition layer are stepped and the pixel definition layer is black.

In some embodiments, the opening is circular, elliptical, or arcuate in shape in the horizontal direction.

In some embodiments, an orthographic projection of the light emitting device layer on the base substrate is within an orthographic projection range of the color resistance layer on the base substrate.

In some embodiments, the display panel further comprises: a touch electrode layer disposed on the second inorganic layer and including a plurality of touch electrodes; the shading layer comprises a plurality of shading patterns, and the shading patterns are covered on the touch control electrodes in a one-to-one correspondence manner; and the organic protective layer covers the second inorganic layer and the shading layer.

In some embodiments, the material of the first inorganic layer and the second inorganic layer comprises at least one of silicon nitride or silicon oxide.

In some embodiments, the slope angle of the sidewalls of the pixel defining layer is less than 30 degrees, and the optical density of the pixel defining layer ranges between 3.5 and 4.5.

The application also provides a preparation method of the display panel, which comprises the following steps:

providing a substrate base plate;

sequentially forming a thin film transistor array layer, an anode and a pixel definition layer on the substrate, and patterning the pixel definition layer to form an opening at a position corresponding to the anode, wherein the pixel definition layer is opaque; forming a light emitting device layer within the opening; covering a first inorganic layer on the pixel defining layer and the light emitting device layer; forming a color resistance layer on the first inorganic layer in an ink-jet printing mode and corresponding to the opening; covering an organic flat layer on the first inorganic layer and the color resistance layer; and covering a second inorganic layer on the organic planarization layer.

The display panel and the manufacturing method thereof have the advantages that the pixel definition layer is directly used as a black matrix, and the color resistance layer is formed in the thin film packaging layer in an ink-jet printing mode, so that the distance between the light-emitting device layer and the color film is reduced, and further the transmittance, the visual angle and the bending performance of the display panel are improved. And the color resistance layer is formed by ink-jet printing, so that the influence on the light-emitting device layer and the thin film packaging layer can be avoided, the preparation process can be simplified, the production cost can be reduced, and the yield can be improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a display panel according to an embodiment of the present application;

FIG. 2 is an enlarged view of a pixel defining layer and an opening thereof according to an embodiment of the present disclosure;

FIG. 3 is a schematic view of an inkjet printed color resist layer in different shaped openings according to an embodiment of the present application;

FIG. 4 is a schematic view of an opening shape design in an embodiment of the present application;

fig. 5 is a flowchart of a method for manufacturing a display panel in an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated in a particular manner, and are not to be construed as limiting the present application. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.

The following disclosure provides many different embodiments or examples for implementing different features of the application. In order to simplify the disclosure of the present application, specific example components and arrangements are described below. Of course, they are merely examples and are not intended to limit the present application. Moreover, the present application may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, examples of various specific processes and materials are provided herein, but one of ordinary skill in the art may recognize applications of other processes and/or use of other materials.

The technical solution of the present application will now be described with reference to specific embodiments.

As shown in fig. 1, the present application provides a display panel 100, and more particularly, an Organic Light-Emitting Diode (Organic Light-Emitting Diode) display panel, which includes a substrate 10, a thin film transistor array layer 20, an anode 30, a pixel defining layer 40, a Light-Emitting device layer 50, a thin film encapsulation layer 60, and a color resistance layer 70.

The thin film transistor array layer 20 is arranged on the substrate base plate 10; the anode 30 is disposed on the thin film transistor array layer 20; the pixel defining layer 40 covers the thin film transistor array layer 20 and is provided with an opening OP at a position corresponding to the anode 30; the light emitting device layer 50 is disposed within the opening OP; the thin film encapsulation layer 60 covers the pixel defining layer 40 and the light emitting device layer 50; the color-resist layer 70 is disposed in the thin-film encapsulation layer 60 and located in the opening OP; wherein the pixel defining layer 40 is opaque.

The substrate 10 may be a glass substrate or a flexible substrate, and the present application is not particularly limited.

The thin film transistor array layer 20 includes an inorganic stack layer and a thin film transistor in the inorganic stack layer. The inorganic stack layer includes, but is not limited to, a gate insulating layer and an interlayer insulating layer, and the thin film transistor includes an active layer, a gate electrode, and source/drain electrodes. The thin film transistor array layer 20 may be any well-known thin film transistor array layer, and the present application is not particularly limited thereto.

The opening OP formed after patterning the pixel defining layer 40 is a pixel region, and the pixel defining layer 40 is made of an opaque material, including but not limited to black polyimide.

The light emitting device layer 50 may include a hole injection layer disposed on the anode 30, a hole transport layer disposed on the hole injection layer, a light emitting layer disposed on the hole transport layer, an electron transport layer disposed on the light emitting layer, an electron injection layer disposed on the electron transport layer, and a cathode disposed on the electron transport layer.

The light emitting layer comprises a red sub-pixel unit, a green sub-pixel unit and a blue sub-pixel unit, wherein the red sub-pixel unit is used for emitting red light, the green sub-pixel unit is used for emitting green light, and the blue sub-pixel unit is used for emitting blue light.

The thin film encapsulation layer 60 is used to isolate external water and oxygen to prevent the display panel 100 from failing.

The color resistance layer 70 includes a red color resistance, a green color resistance and a blue color resistance, and the red color resistance, the green color resistance and the blue color resistance respectively correspond to the red sub-pixel unit, the green sub-pixel unit and the blue sub-pixel unit and filter the light emitted therefrom.

The display panel 100 of the present application uses an opaque material to prepare the pixel defining layer 40, that is, the pixel defining layer is directly used as a black matrix, and the color resist layer 70 is formed in the thin film encapsulation layer 60, so that the distance between the light emitting device layer 50 and the color film is reduced, and the transmittance, the viewing angle, and the bending performance of the display panel 100 are further improved.

In one embodiment of the present application, the thin film encapsulation layer 60 includes a first inorganic layer 61, an organic planarization layer 62, and a second inorganic layer 63.

The first inorganic layer 61 covers the pixel defining layer 40 and the light emitting device layer 50; the organic planarization layer 62 covers the first inorganic layer 61 and the color resist layer 70; the second inorganic layer 63 covers the organic planarization layer 62; wherein the color resistance layer 70 is disposed on the first inorganic layer 61 and within the opening OP.

The material of the first inorganic layer 61 and the second inorganic layer 63 includes at least one of silicon nitride or silicon oxide; the material of the organic planarization layer 62 includes acryl, etc., and the present application is not particularly limited.

In the display panel 100 of the present application, the color resist layer 70 is disposed on the first inorganic layer 61, so that the distance between the light emitting device layer 50 and the color film can be further reduced, and the transmittance and the viewing angle of the display panel 100 can be further improved.

Further, as shown in fig. 2, in an embodiment of the present application, the sidewalls of the pixel defining layer 40 are arranged in a step shape and the pixel defining layer is black.

Since the ink forming the color resist layer 70 and the first inorganic layer 61 have a certain adsorptivity and a large contact angle, the ink is easily adsorbed on the sidewall of the pixel defining layer 40 and cannot fall into the bottom of the opening OP completely in the inkjet printing process, so that the thickness of the color resist layer 70 is difficult to control, and the optical properties are affected.

Therefore, in the present embodiment, the sidewall of the pixel defining layer 40 is configured to be stepped, so that the contact angle and the adsorptivity can be effectively reduced, and even when the precision of the nozzle is not good (i.e. the lower position of the ink drop does not correspond to the center position of the opening OP), the ink can fall into the bottom of the opening OP through the stepped sidewall, thereby ensuring that the color resist layer 70 has a uniform thickness.

Further, in an embodiment of the present application, an inclination angle (taper angle) θ of the sidewall of the pixel defining layer 40 is less than 30 degrees, preferably between 7 and 30 degrees; the height H of the pixel defining layer 40 is preferably 1 μm to 3 μm, and the Optical Density (OD) thereof ranges from 3.5 to 4.5.

In this embodiment, by setting the inclination angle θ of the sidewall of the pixel defining layer 40 within this range, the contact angle and the adsorptivity can be further reduced while maintaining a certain aperture ratio, thereby ensuring that the color resist layer 70 has a uniform thickness; and the height H and the optical density are set in the range, so that the reflectivity of the panel can be further reduced, and the light leakage of pixels can be avoided.

Further, in an embodiment of the present application, an orthographic projection of the light emitting device layer 50 on the substrate base plate 10 is located within an orthographic projection range of the color resistance layer 70 on the substrate base plate 10. That is, the boundary of the color resistance layer 70 is larger than the boundary of the light emitting device layer 50.

It should be noted that, in the embodiment of the present application, by setting the boundary of the color resist layer 70 to be larger than the boundary of the light emitting device layer 50, the color resist layer 70 can completely cover the light emitting device layer 50, and thus the reflectivity of the panel can be further reduced, the viewing angle can be increased, and light leakage of pixels can be avoided.

As shown in fig. 3 and 4, when the opening OP is shaped as a rectangle C with corners, the corners of the ink are difficult to fill due to physical forces during inkjet printing, which easily causes problems such as light leakage of pixels and uneven thickness of the color resist layer 70.

Therefore, in an embodiment of the present application, the shape of the opening OP in the horizontal direction is circular, elliptical, or arc.

By configuring the shape of the opening OP as a circle, an ellipse, or an arc, it is able to avoid the problems of pixel light leakage caused by the corners and uneven thickness of the color resist layer 70.

It is to be understood that the circle a shown in fig. 3 and the pixel opening shape shown in fig. 4 are merely examples, and the shape of the opening OP may be an ellipse or an arc without corners.

As shown in fig. 1, the display panel 100 may further include a touch electrode layer 80, a light shielding layer 42 and an organic protection layer 90.

The touch electrode layer 80 is disposed on the second inorganic layer 63 and includes a plurality of touch electrodes; the shading layer 42 comprises a plurality of shading patterns, and the shading patterns are covered on the touch control electrodes in a one-to-one correspondence manner; the organic protection layer 90 covers the second inorganic layer 63 and the light-shielding layer 42.

It is understood that the reference numeral 80 shown in fig. 1 may also represent the touch electrode, and the reference numeral 42 may also represent the light-shielding pattern.

Specifically, the touch electrode layer 80 is a metal grid structure and is disposed between the pixel openings to avoid affecting the pixel light emission; the organic protection layer 90 is used to planarize the light-shielding layer 42 and protect the display panel 100, and is made of an organic transparent material, such as a photoresist material.

The light-shielding layer 42 may be a black matrix material. Since the cathode of the light emitting device layer 50 is generally disposed on the whole surface and has a certain reflectivity, the light shielding layer 42 is disposed to reduce the reflection of the touch electrode layer 80 and the reflection of the cathode, thereby further improving the optical properties of the display panel 100.

As shown in fig. 5, the present application further provides a method for manufacturing the display panel 100, the method comprising the following steps:

s1: providing a substrate 10;

s2: sequentially forming a thin film transistor array layer 20, an anode 30 and a pixel defining layer 40 on the substrate 10, and patterning the pixel defining layer 40 to form an opening OP at a position corresponding to the anode 30, wherein the pixel defining layer 40 is opaque;

s3: forming a light emitting device layer 50 within the opening OP;

s4: covering the pixel defining layer 40 and the light emitting device layer 50 with a first inorganic layer 61;

s5: forming a color resist layer 70 on the first inorganic layer 61 in an ink-jet printing manner and in correspondence with the opening OP;

s6: covering the first inorganic layer 61 and the color resistance layer 70 with an organic planarization layer 62;

s7: a second inorganic layer 63 is coated on the organic planarization layer 62.

According to the manufacturing method of the display panel, the pixel definition layer 40 is directly used as a black matrix, and the color resistance layer 70 is formed on the first inorganic layer 61 in an inkjet printing manner, so that the distance between the light-emitting device layer 50 and a color film is reduced, and the transmittance, the viewing angle and the bending performance of the display panel 100 are improved. The formation of the color resist layer 70 by inkjet printing can avoid the influence on the light emitting device layer 50 and the thin film encapsulation layer 60, and can simplify the manufacturing process, reduce the production cost, and improve the yield.

Further, in the step of patterning the pixel defining layer 40 to form the opening OP at the position corresponding to the anode 30, the pixel defining layer 40 is patterned using a halftone mask to form a sidewall having a step shape.

Therefore, in the present embodiment, the pixel defining layer 40 is patterned by using a halftone mask to form a step-shaped sidewall, so that the contact angle and the adsorptivity can be effectively reduced, and even when the precision of the nozzle is not good (i.e., the position under the ink drop does not correspond to the center position of the opening OP), the ink can fall into the bottom of the opening OP by the step-shaped sidewall, thereby ensuring that the photoresist layer 70 has a uniform thickness.

In an embodiment of the present application, a supporting pillar 41 may be further formed above the pixel defining layer 40, the supporting pillar 41 is integrally formed when the pixel defining layer 40 is patterned by using a halftone mask, and the supporting pillar 41 is mainly used for supporting a mask during the inkjet printing process of the light emitting device layer 50 or the color resist layer 70, so as to further improve the accuracy of the inkjet printing.

In an embodiment of the present application, after the step S7, the preparation method may further include the steps of:

s8: forming a touch electrode layer 80 on the second inorganic layer 63, wherein the touch electrode layer 80 is patterned to form a plurality of touch electrodes;

s9: forming a light shielding layer 42 on the touch electrode layer 80, wherein the light shielding layer 42 is patterned to form a plurality of light shielding patterns, and the light shielding patterns are covered on the touch electrode in a one-to-one correspondence manner;

s10: an organic protective layer 90 is covered on the second inorganic layer 63 and the light-shielding layer 42.

For the detailed description of the layers, reference may be made to the display panel 100, which is not repeated in the present manufacturing method.

In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

The above embodiments of the present application are described in detail, and specific examples are applied in the present application to explain the principles and implementations of the present application, and the description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application; those of ordinary skill in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications or substitutions do not depart from the spirit and scope of the present disclosure as defined by the appended claims.

Claims

1. A display panel, comprising:

a substrate base plate;

a thin film transistor array layer disposed on the substrate base plate;

an anode disposed on the thin film transistor array layer;

the pixel defining layer covers the thin film transistor array layer and is provided with an opening at a position corresponding to the anode;

a light emitting device layer disposed within the opening;

a thin film encapsulation layer covering the pixel defining layer and the light emitting device layer; and

the color resistance layer is arranged in the thin film packaging layer and is positioned in the opening;

wherein the pixel definition layer is opaque.

2. The display panel of claim 1, wherein the thin film encapsulation layer comprises:

a first inorganic layer covering the pixel defining layer and the light emitting device layer;

the organic flat layer covers the first inorganic layer and the color resistance layer; and

a second inorganic layer overlying the organic planarization layer;

wherein the color-resist layer is disposed on the first inorganic layer and within the opening.

3. The display panel of claim 1, wherein the sidewalls of the pixel definition layer define a step shape and the pixel definition layer defines a black color.

4. The display panel according to claim 1, wherein an orthogonal projection of the light-emitting device layer on the base substrate is within an orthogonal projection range of the color resist layer on the base substrate.

5. The display panel according to claim 2, characterized in that the display panel further comprises:

a touch electrode layer disposed on the second inorganic layer and including a plurality of touch electrodes;

the shading layer comprises a plurality of shading patterns, and the shading patterns are covered on the touch control electrodes in a one-to-one correspondence manner; and

and the organic protective layer covers the second inorganic layer and the shading layer.

6. The display panel according to claim 1, wherein the opening defines a shape in a horizontal direction, such as a shape of a circle, an ellipse, or an arc.

7. The display panel of claim 3, wherein the inclination angle of the sidewall of the pixel definition layer is less than 30 degrees, and the optical density of the pixel definition layer is in a range from 3.5 to 4.5.

8. A method for manufacturing a display panel, the method comprising:

providing a substrate base plate;

sequentially forming a thin film transistor array layer, an anode and a pixel definition layer on the substrate, and patterning the pixel definition layer to form an opening at a position corresponding to the anode, wherein the pixel definition layer is opaque;

forming a light emitting device layer within the opening;

covering a first inorganic layer on the pixel defining layer and the light emitting device layer;

forming a color resistance layer on the first inorganic layer in an ink-jet printing mode and corresponding to the opening;

covering an organic flat layer on the first inorganic layer and the color resistance layer; and

a second inorganic layer is overlaid on the organic planarization layer.

9. The method for manufacturing a display panel according to claim 8, wherein in the step of patterning the pixel defining layer to form an opening at a position corresponding to the anode electrode, the pixel defining layer is patterned using a halftone mask to form a sidewall having a step shape.

10. The method for manufacturing a display panel according to claim 8, wherein the shape of the opening in the horizontal direction defines a shape, an ellipse, or an arc.