CN111682124B - Display substrate, preparation method thereof and display panel - Google Patents

Abstract

The invention provides a display substrate, a preparation method thereof and a display panel, belongs to the technical field of display, and can at least partially solve the problem of poor display effect of the existing display panel due to light leakage. A display substrate of the present invention includes: a substrate; at least one light emitting layer on the substrate; at least one top light conversion layer, which is positioned on one side of the light emitting layer far away from the substrate, wherein the color of partial light emitted from the light emitting layer is changed after passing through the top light conversion layer; at least one bottom light conversion layer located between the light emitting layer and the substrate, wherein the color of the other part of light emitted from the light emitting layer changes after passing through the bottom light conversion layer; and a reflective layer at least between the bottom light conversion layer and the substrate, the reflective layer for reflecting light directed thereto.

Description

Display substrate, manufacturing method thereof, and display panel

technical field

The invention belongs to the field of display technology, and in particular relates to a display substrate, a preparation method thereof, and a display panel.

Background technique

With the continuous development and progress of display technology, the display panel can present a variety of natural colors in the largest range, and bring a more realistic and shocking visual experience to users. In an existing display panel, a wide color gamut is adopted, that is, the light source is a quantum dot light source, and the quantum dot light source has display advantages such as narrow light spectrum and high color purity. Specifically, the light-emitting modes of the quantum dot light-emitting source are divided into two types of light-emitting modes: photoluminescence and electroluminescence.

A display panel of a photoluminescent quantum dot light source is a pixelated quantum dot color film (QDCF) display panel, which can excite quantum particles of other colors (such as red or green) with the light of a color (such as blue light) light source. Click for full color display. However, due to the light leakage of the light source, the color gamut of the display panel is affected, thereby affecting the display effect.

Contents of the invention

The present invention at least partly solves the problem of poor display effect caused by light leakage in existing display panels, and provides a display substrate with good display effect.

The technical solution adopted to solve the technical problems of the present invention is a display substrate, comprising:

Substrate;

at least one light-emitting layer on the substrate;

At least one top light conversion layer, located on the side of the light emitting layer away from the substrate, the color of part of the light emitted from the light emitting layer changes after passing through the top light conversion layer;

At least one bottom light conversion layer, located between the light-emitting layer and the substrate, the color of another part of the light emitted from the light-emitting layer changes after passing through the bottom light conversion layer;

A reflective layer is located at least between the bottom light conversion layer and the substrate, and the reflective layer is used for reflecting light incident thereto.

Further preferably, the light-emitting layer is a plurality of spaced distribution, part of the light-emitting layer corresponds to the top light conversion layer one-to-one, and the top light conversion layer corresponds to the bottom light conversion layer one-to-one, and The top light conversion layer and the bottom light conversion layer corresponding to each other are both the first color conversion layer or the second color conversion layer, wherein the first color conversion layer changes the light passing through it into the first color light, the second color conversion layer is for changing the light passing through it into light of the second color.

It is further preferred that three successively adjacent ones of the multiple light-emitting layers are divided into one group, each group of light-emitting layers includes a first light-emitting layer, a second light-emitting layer and a third light-emitting layer, and the first light-emitting layer The top light conversion layer and the bottom light conversion layer corresponding to the layer are the first color conversion layer, and the top light conversion layer and the bottom light conversion layer corresponding to the second light-emitting layer are the second color conversion layer , the third light-emitting layer does not correspond to the top light conversion layer and the bottom light conversion layer, and all the light-emitting layers can emit light of a third color.

Further preferably, the display substrate further includes: a top-fill layer located on a side of the third light-emitting layer away from the substrate, and light emitted from the third light-emitting layer can pass through the top-fill layer; An underfill layer is located between the third light emitting layer and the substrate, and the light emitted from the third light emitting layer can pass through the underfill layer.

Further preferably, at least part of the reflective layer is located between the underfill layer and the substrate.

Further preferably, the top-fill layer and the bottom-fill layer are scatter particle layers.

Further preferably, the display substrate further includes: a plurality of light-shielding layers located between any adjacent top light conversion layers and between any adjacent bottom light conversion layers.

The technical solution adopted to solve the technical problem of the present invention is a method for preparing a display substrate. Based on the above-mentioned display substrate, the preparation method includes:

forming a reflective layer on the substrate for reflecting light incident thereto;

forming a bottom light conversion layer on the side of the reflective layer away from the substrate;

forming a light-emitting layer on the side of the bottom light conversion layer away from the substrate;

A top-light conversion layer is formed on the side of the light-emitting layer away from the substrate, the color of the part of light emitted from the light-emitting layer changes after passing through the top-light conversion layer, and the light emitted from the light-emitting layer changes The color of the other part of the light emitted by the layer changes after passing through the bottom light conversion layer.

The technical solution adopted to solve the technical problem of the present invention is a display panel, including the above-mentioned display substrate.

Further preferably, the display panel is an organic light emitting diode display panel or a micro light emitting diode display panel.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, together with the following specific embodiments, are used to explain the present invention, but do not constitute a limitation to the present invention. In the attached picture:

FIG. 1 is a schematic structural view of a display substrate according to an embodiment of the present invention;

2a to 2f are schematic structural diagrams showing various steps in the preparation process of the substrate according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a display substrate according to an embodiment of the present invention;

Fig. 4a is the relationship between the thickness of the anode sublayer of the display substrate and the light transmittance according to the embodiment of the present invention;

Fig. 4b is the relationship between the thickness of the cathode sublayer of the display substrate and the light transmittance according to the embodiment of the present invention;

FIG. 5 is a schematic structural diagram of a display substrate according to an embodiment of the present invention;

6 is a schematic structural view of a light emitting layer of a display substrate according to an embodiment of the present invention;

Wherein, reference numerals are: 1. substrate; 2. light emitting layer; 21. first light emitting layer; 22. second light emitting layer; 23. third light emitting layer; 3. top light conversion layer; 4. bottom light conversion layer; 5, reflective layer; 6, top filling layer; 7, bottom filling layer; 8, light shielding layer; 91, insulating layer, 92, first planarization layer; 93, second planarization layer; 94, transistor; 95 , Pixel-limited structure.

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. In the various figures, identical elements are indicated with similar reference numerals. For the sake of clarity, various parts in the drawings have not been drawn to scale. Also, some well-known parts may not be shown in the drawings.

In the following, many specific details of the present invention, such as structures, materials, dimensions, processes and techniques of components, are described for a clearer understanding of the present invention. However, the invention may be practiced without these specific details, as will be understood by those skilled in the art.

Example 1:

As shown in Figures 1 to 6, this embodiment provides a display substrate, including:

substrate1;

at least one light-emitting layer 2, located on the substrate 1;

At least one top light conversion layer 3 is located on the side of the light emitting layer 2 away from the substrate 1, and the color of part of the light emitted from the light emitting layer 2 changes after passing through the top light conversion layer 3;

At least one bottom light conversion layer 4 is located between the light-emitting layer 2 and the substrate 1, and the color of another part of the light emitted from the light-emitting layer 2 changes after passing through the bottom light conversion layer 4;

The reflective layer 5 is at least located between the bottom light conversion layer 4 and the substrate 1 , and the reflective layer 5 is used to reflect light incident thereto.

Wherein, that is to say, the structure of the display substrate from the substrate 1 to the side away from the substrate 1 is the substrate 1 , the reflective layer 5 , the bottom light conversion layer 4 , the light emitting layer 2 , and the top light conversion layer 3 . A part of the light of the light-emitting layer 2 is emitted directly through the top light conversion layer 3; another part of the light of the light-emitting layer 2 directly passes through the bottom light conversion layer 4 to the reflective layer 5, is reflected by the reflective layer 5, and finally passes through the top light conversion layer 3 The light emitted from the top light conversion layer 3 is used to form a display image. It can be seen from this moment that the side of the top light conversion layer 3 away from the substrate 1 is the light exit side of the display substrate.

It should be noted that the top light conversion layer 3 is not necessarily on the top of the bottom light conversion layer 4, and the bottom light conversion layer 4 is not necessarily on the top of the top light conversion layer 3, both are relative to the substrate 1, the top light conversion Layer 3 is farther from substrate 1 than bottom light-converting layer 4 . When the substrate 1 is at the bottom, the top light conversion layer 3 is above the bottom light conversion layer 4 , and when the substrate 1 is at the top, the top light conversion layer 3 is below the bottom light conversion layer 4 .

In the display substrate of this embodiment, by setting the bottom light conversion layer 4 and the reflective layer 5, the light emitted from the light-emitting layer 2 to the substrate 1 is converted by the bottom light conversion layer 4 and then reflected by the reflective layer 5, and finally directed to the light-emitting side. , used to form the display screen. Compared with the display substrate of the prior art (which does not have the bottom light conversion layer 4 and the reflective layer 5, so the light emitted from the light-emitting layer 2 to the substrate 1 cannot be emitted from the light-emitting side), the display substrate of this embodiment reduces the light-emitting layer 2, improve light utilization efficiency, thereby ensuring the color gamut of the display screen of the display base substrate, and further improving the display effect of the display substrate.

Preferably, the light-emitting layer 2 is a plurality of spaced distributions, part of the light-emitting layer 2 corresponds to the top light conversion layer 3 one-to-one, the top light conversion layer 3 corresponds to the bottom light conversion layer 4, and the top light conversion layers corresponding to each other 3 and the bottom light conversion layer 4 are both the first color conversion layer or the second color conversion layer, wherein the first color conversion layer is for the light passing through it to become the first color light, and the second color conversion layer is for the The light becomes light of the second color.

Wherein, that is to say, the top light conversion layer 3 and the bottom light conversion layer 4 corresponding to the same light-emitting layer 2 have the same conversion effect on light, that is, the light emitted by the light-emitting layer 2 can be converted into the first color light, or The light emitted by the light-emitting layer 2 can be converted into light of the second color, so that the colors of the light emitted from the light-emitting side of one light-emitting layer 2 are consistent.

Specifically, three successively adjacent luminescent layers 2 are divided into one group, and each group of luminescent layers 2 includes a first luminescent layer 21, a second luminescent layer 22, and a third luminescent layer 23, and the first luminescent layer 21 corresponds to The top light conversion layer 3 and the bottom light conversion layer 4 are the first color conversion layer, the top light conversion layer 3 and the bottom light conversion layer 4 corresponding to the second light-emitting layer 22 are the second color conversion layer, and the third light-emitting layer 23 does not correspond to the top light conversion layer 3 and the bottom light conversion layer 4, and all light emitting layers 2 can emit light of the third color.

Wherein, that is to say, each group of light-emitting layers 2 constitutes a pixel unit, and each light-emitting layer 2 of the pixel unit is equivalent to a light-emitting source of a sub-pixel unit. The first light-emitting layer 21, the second light-emitting layer 22 and the third light-emitting layer 23 in each group can emit light of a third color, and the light of the first light-emitting layer 21 passes through the corresponding top light conversion layer 3 and bottom light conversion layer 4 The light of the second light-emitting layer 22 passes through the corresponding top light conversion layer 3 and the bottom light conversion layer 4, and then is converted into light of the second color and is emitted from the light-emitting side; the light of the third light-emitting layer 23 Since there is no corresponding top light conversion layer 3 and bottom light conversion layer 4, the third color light emitted by it is finally emitted from the light exit side.

Through the above structure, each group of light-emitting layers 2 finally emits three different lights of the first color light, the second color light and the third color light from the light-emitting side to form the light emission of the sub-pixel unit.

It should be noted that the first color light may be red light, the second color light may be green light, and the third color light may be blue light. The light emitting layer 2 can be a blue light source or a UV light source.

Preferably, the display substrate further includes: a top-fill layer 6 located on the side of the third light-emitting layer 23 away from the substrate 1, the light emitted from the third light-emitting layer 23 can pass through the top-fill layer 6; an under-fill layer 7, Located between the third light-emitting layer 23 and the substrate 1 , the light emitted from the third light-emitting layer 23 can pass through the top-fill layer 6 .

Wherein, that is to say, the top-fill layer 6 and the bottom-fill layer 7 correspond to the third light-emitting layer 23, which not only enables the light of the third light-emitting layer 23 to be emitted from the light-emitting side, but also ensures that the third light-emitting layer 23 is compatible with the first light-emitting layer. The structural consistency of the light emitting layer 21 and the second light emitting layer 22.

Specifically, the top-fill layer 6 and the bottom-fill layer 7 are dispersion particle layers, so that the light of the third light-emitting layer 23 can be emitted more uniformly from the light-emitting side.

Preferably, at least part of the reflective layer 5 is located between the underfill layer 7 and the substrate 1 .

Wherein, that is to say, the reflective layer 5 corresponds to the positions of all the light emitting layers 2 . A part of the light of the third luminescent layer 23 is emitted directly through the top-fill layer 6; another part of the light of the third luminescent layer 23 directly passes through the bottom light conversion layer 4 to the reflective layer 5, is reflected by the reflective layer 5 and finally passes through the top-fill layer 6, the light emitted from the top-fill layer 6 is used to form a display image.

Preferably, the display substrate further includes: a plurality of light shielding layers 8 (black matrix), located between any adjacent top light conversion layers 3 and between any adjacent bottom light conversion layers 4 .

Wherein, the arrangement of the light-shielding layer 8 can ensure that the light emitted by adjacent light-emitting layers 2 will not interfere with each other, thereby ensuring the light-emitting effect of the sub-pixel unit.

In addition, the display substrate of this embodiment further includes: a plurality of transistors 94, located between the substrate 1 and the reflective layer 2, used to provide electrical signals to the light-emitting layer 2 to make it emit light, as shown in FIG. 3 and FIG. 5 .

The display substrate of this embodiment further includes: a plurality of pixel-defining structures 95 located between any adjacent light-emitting layers 2 .

It should be noted that the display substrate of this embodiment may be an organic light emitting diode display substrate (OLED). As shown in FIG. .

The material for forming the anode sublayer may be indium tin oxide (ITO) with a thickness of 100A, and the material for forming the cathode sublayer may be indium zinc oxide (IZO) with a thickness of 200A. The light-emitting layer 2 of this structure can achieve a transmittance of more than 90% for visible light with a wavelength of 520nm-680nm, thereby ensuring the light extraction rate of light reflected from the emitting layer. Figure 4a and Figure 4b respectively show the relationship between film thickness and light transmittance of different materials.

The display substrate of this embodiment can also be a micro light-emitting diode display substrate (u-LED). layers and electrode structures.

Example 2:

As shown in Figures 1 to 6, this embodiment provides a method for preparing a display substrate. Based on the display substrate in Embodiment 1, the preparation method includes:

S11 , forming a transistor 94 on the substrate 1 , and forming a first insulating layer on the transistor 94 .

S12 , as shown in FIG. 2 a and FIG. 2 b , forming a reflective layer 5 on the substrate 1 , and forming an insulating layer 91 on the reflective layer 5 .

Wherein, the reflective layer 5 can be a metal layer, such as Ag, with a thickness of 1000 Å.

S13 , as shown in FIG. 2 c , forming a plurality of light shielding layers 8 on the insulating layer 91 on the substrate 1 .

S14 , as shown in FIG. 2 c , forming a bottom light conversion layer 4 on the side of the reflective layer 5 away from the substrate 1 , that is, forming a plurality of bottom light conversion layers 4 between the light shielding layers 8 .

S15, as shown in Figure 2d, form a first planarization layer 92 on the light-shielding layer 8 and the bottom light conversion layer 4, and form a through hole in the light-shielding layer 8 to expose part of the transistor 94 (not shown in Figure 2d , can refer to Figure 3 and Figure 5).

S16, as shown in FIG. 2e, form a light-emitting layer 2 on the side of the bottom light conversion layer 4 away from the substrate 1, that is, form a light-emitting layer 2 on the first planarization layer 92, and connect the light-emitting layer 2 to the transistor 94 through a through hole .

Specifically, for an organic light emitting diode display substrate, an anode sublayer and a pixel defining structure 95 are first formed on the first planarization layer 92; secondly, a light emitting sublayer is formed between the pixel defining structures 95 and on the anode sublayer; finally A cathode sublayer is formed between the light emitting sublayer and the pixel defining structure 95 . The material for forming the anode sublayer may be indium tin oxide (ITO) with a thickness of 100A, and the material for forming the silver electrode sublayer may be indium zinc oxide (IZO) with a thickness of 200A. The light-emitting layer 2 of this structure can achieve a transmittance of more than 90% for visible light with a wavelength of 520nm-680nm, thereby ensuring the light extraction rate of light reflected from the light-emitting layer.

The relationship between the thickness of the indium tin oxide (ITO) film layer and the light transmittance is shown in Figure 4a, and the relationship between the thickness of the indium zinc oxide (IZO) film layer and the light transmittance is shown in Figure 4b.

S17 , as shown in FIG. 2f , forming a second planarization layer 93 on the light emitting layer 2 .

S18 , as shown in FIG. 1 , forming the top light conversion layer 3 on the side of the light emitting layer 2 away from the substrate 1 , that is, forming the top light conversion layer 3 and the light shielding layer 8 on the second planarization layer 93 . Part of the light emitted from the light-emitting layer 2 passes through the top light conversion layer 3 and changes in color, and another part of the light emitted from the light-emitting layer 2 passes through the bottom light conversion layer 4 and changes in color.

The top light conversion layer 3 and the bottom light conversion layer 4 can be made of the same material, or different materials but with the same light emission spectrum. The forming material of the light-shielding layer 8 needs to be selected according to the material of the top light conversion layer 3 or the bottom light conversion layer 4. If the top light conversion layer 3 and the bottom light conversion layer 4 are formed by ink material (INK), then it is the same as the top light conversion layer. The thickness of the light-shielding layer 8 on the same layer as layer 3 is 6-20um, and the thickness of the light-shielding layer 8 on the same layer as the bottom light conversion layer 4 can be appropriately reduced; the light transmittance (OD) of the light-shielding layer 8 is greater than 2. The light-shielding layer 8 on the same layer as the bottom light conversion layer 4 can be prepared by a high-temperature process. The material of the light-shielding layer 8 is resin, and the main curing is usually performed by a conventional 230° C. process.

For the organic light emitting diode display substrate, in order to ensure the performance of the light-emitting layer 2, all film layers in the preparation process adopt a low-temperature preparation process.

It should be noted that the insulating layer 91, the first planarization layer 92, and the second planarization layer 93 corresponding to the positions of the light-emitting layer 2 are light-transmissive, that is, they have a better transmittance to visible light (preferred transmittance rate greater than 95%).

In the preparation method of the display substrate in this embodiment, by setting the bottom light conversion layer 4 and the reflective layer 5, the light emitted from the light-emitting layer 2 to the substrate 1 is converted by the bottom light conversion layer 4 and then reflected by the reflective layer 5, and finally It is emitted to the light-emitting side and used to form a display screen. Compared with the display substrate of the prior art (which does not have the bottom light conversion layer 4 and the reflective layer 5, so the light emitted from the light-emitting layer 2 to the substrate 1 cannot be emitted from the light-emitting side), the display substrate of this embodiment reduces the light emission The light leakage problem of the layer 2 can improve the light utilization rate, thereby ensuring the color gamut of the display screen of the display base substrate, and further improving the display effect of the display substrate.

Example 3:

This embodiment provides a display panel, including the display substrate in Embodiment 1.

Preferably, the display panel is an organic light emitting diode display panel or a micro light emitting diode display panel.

Specifically, the display panel can be any product or component with a display function, such as electronic paper, mobile phone, tablet computer, television, monitor, notebook computer, digital photo frame, and navigator.

It should be noted that in this article, relational terms such as first and second etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is a relationship between these entities or operations. There is no such actual relationship or order between them. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device. Without further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

Embodiments according to the present invention are described above, and these embodiments do not describe all details in detail, nor do they limit the invention to only the specific embodiments described. Obviously many modifications and variations are possible in light of the above description. This description selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can make good use of the present invention and its modification on the basis of the present invention. The invention is to be limited only by the claims, along with their full scope and equivalents.

Claims (8)

1. A display substrate, characterized in that, comprising: Substrate; at least one light-emitting layer on the substrate; At least one top light conversion layer, located on the side of the light emitting layer away from the substrate, the color of part of the light emitted from the light emitting layer changes after passing through the top light conversion layer; At least one bottom light conversion layer, located between the light-emitting layer and the substrate, the color of another part of light emitted from the light-emitting layer changes after passing through the bottom light conversion layer; a reflective layer at least between the bottom light conversion layer and the substrate, the reflective layer for reflecting light incident thereto; a plurality of transistors, located between the substrate and the reflective layer, for making the light-emitting layer emit light by providing electrical signals; A plurality of light-shielding layers, located between any adjacent top light conversion layers and between any adjacent bottom light conversion layers; through holes are formed in the light-shielding layers to expose part of the transistors; The light-emitting layer is a plurality of spaced distribution, part of the light-emitting layer corresponds to the top light conversion layer one-to-one, the top light conversion layer corresponds to the bottom light conversion layer one-to-one, and the corresponding The top light conversion layer and the bottom light conversion layer are both a first color conversion layer or a second color conversion layer, wherein the first color conversion layer changes the light passing through it into the first color light, and the second color conversion layer The color conversion layer changes light passing through it into light of a second color. 2. The display substrate according to claim 1, wherein three of the plurality of light-emitting layers adjacent to each other are divided into one group, and each group of light-emitting layers includes a first light-emitting layer, a second light-emitting layer and the third light-emitting layer, the top light conversion layer and the bottom light conversion layer corresponding to the first light-emitting layer are the first color conversion layer, and the top light conversion layer and the bottom light conversion layer corresponding to the second light-emitting layer are The bottom light conversion layer is a second color conversion layer, the third light-emitting layer does not correspond to the top light conversion layer and the bottom light conversion layer, and all the light-emitting layers can emit light of a third color. 3. The display substrate according to claim 2, further comprising: a top-fill layer, located on a side of the third light-emitting layer away from the substrate, and light emitted from the third light-emitting layer can pass through the top-fill layer; An underfill layer is located between the third light emitting layer and the substrate, and the light emitted from the third light emitting layer can pass through the underfill layer. 4. The display substrate according to claim 3, wherein at least part of the reflective layer is located between the underfill layer and the substrate. 5 . The display substrate according to claim 3 , wherein the top-fill layer and the bottom-fill layer are scatter particle layers. 6. A method for preparing a display substrate, characterized in that, based on the display substrate according to any one of claims 1 to 5, the preparation method comprises: forming a plurality of transistors on a substrate; forming a reflective layer on the substrate for reflecting light incident thereto; forming a bottom light conversion layer and a light-shielding layer on the side of the reflective layer away from the substrate, and forming a via hole through the light-shielding layer to expose part of the transistor; forming a light-emitting layer on the side of the bottom light conversion layer away from the substrate; A top-light conversion layer is formed on the side of the light-emitting layer away from the substrate, the color of the part of light emitted from the light-emitting layer changes after passing through the top-light conversion layer, and the light emitted from the light-emitting layer changes The color of another part of the light emitted by the layer changes after passing through the bottom light conversion layer. 7. A display panel, comprising the display substrate according to any one of claims 1 to 5. 8 . The display panel according to claim 7 , wherein the display panel is an organic light emitting diode display panel or a micro light emitting diode display panel.

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