WO2016045271A1

WO2016045271A1 - Display substrate and preparation method therefor, and display device

Info

Publication number: WO2016045271A1
Application number: PCT/CN2015/070887
Authority: WO
Inventors: 舒适; 谷敬霞
Original assignee: 京东方科技集团股份有限公司
Priority date: 2014-09-25
Filing date: 2015-01-16
Publication date: 2016-03-31
Also published as: CN104299973A; CN104299973B

Abstract

Provided are a display substrate and a preparation method therefor, and a display device. Since a quantum dot light-emitting device where a quantum dot light-emitting layer is located is made of the same quantum dot material, and the quantum dot light-emitting layer is integratedly arranged on the same layer, there is no need to conduct patterning on the quantum dot light-emitting layer, thereby avoiding the problem of colour offset in the prior art caused by adopting different quantum dot materials.

Description

Display substrate, preparation method thereof, and display device

Technical field

The present invention relates to the field of display technologies, and in particular, to a display substrate, a method for fabricating the same, and a display device.

Background technique

Quantum dot semiconductor displays are promising future display technologies. By controlling the particle size of the quantum dot semiconductor material, the forbidden band width can be adjusted to achieve the purpose of controlling the color of the light. Quantum dots have the characteristics of active illumination, fast response, and high color purity, which makes the expected display effect far exceed the liquid crystal display mode. At present, there are two main reasons for limiting the development of quantum dot color display: one is that quantum dots are difficult to be patterned, and the other is that quantum dots produce color shifts.

Since quantum dots are not small molecular organic materials, there is currently no patterning means suitable for mass production. Since the quantum dot luminescent layer is very thin, the conventional yellow light process uses a photoresist, a developing solution, and a stripping solution, which seriously damages the quantum dot luminescent layer.

At the same time, it is also impossible to carry out patterning by evaporation method and inkjet method; the currently accepted method in the industry is the transfer method, but the method is very immature, the process is extremely difficult, and currently no mass production, and the transfer equipment There are also few suppliers, which restricts the development of quantum dot semiconductor displays.

The display substrate includes a base substrate and a plurality of pixel units formed on the base substrate, each of the pixel units including a plurality of sub-pixel units of different colors for color display. When color display is selected using different quantum dot materials (for example, one pixel unit includes RGB three sub-pixel units), the efficiency of the different luminescent materials is not synchronized, and the color shift of the picture may occur due to the extended use time.

Summary of the invention

The object of the present invention is to solve the problem that the quantum dot semiconductor display in the prior art has difficulty in patterning quantum dots and the color shift of different quantum dot luminescent materials due to different efficiency attenuation, and provides a display substrate and a preparation method thereof Display Device.

The technical solution adopted to solve the technical problem of the present invention is a display substrate comprising a substrate substrate and a plurality of pixel units formed on the base substrate, each pixel unit including a plurality of sub-pixel units;

Each of the sub-pixel units includes a quantum dot light emitting device away from a side of the substrate;

The quantum dot light emitting device includes a quantum dot light emitting layer, and the quantum dot light emitting layers corresponding to the plurality of sub pixel unit are integrally disposed in the same layer;

The sub-pixel unit having a color light wavelength greater than a color light wavelength of the quantum dot light emitting layer is a first type of sub-pixel unit;

The first type of sub-pixel unit includes a light conversion structure corresponding to a side of the substrate substrate corresponding to the quantum dot light-emitting device, and the light conversion structure is configured to convert color light emitted by the quantum dot light-emitting device into the first type The color light corresponding to the pixel unit.

Preferably, the sub-pixel unit may further be a second type of sub-pixel unit having a color light wavelength equal to a color light wavelength of the quantum dot light emitting layer.

Preferably, the first type of sub-pixel unit and the second type of sub-pixel unit comprise a transparent planarization layer disposed adjacent to a side of the substrate substrate corresponding to the quantum dot light-emitting device.

Preferably, the light conversion structure includes a color light conversion layer and a color light filter layer corresponding to the first type of sub-pixel unit, and is configured to pass the color light emitted by the quantum dot light emitting device through the color light conversion layer, and the color light filter. The light layer is then converted into a color light corresponding to the first type of sub-pixel unit.

Preferably, each of the sub-pixel units includes a pixel defining area and a light transmitting area, the light transmitting area being located between the pixel defining area and the pixel defining area of the adjacent sub-pixel unit;

Each of the sub-pixel units includes a thin film transistor on a side of the pixel defining region adjacent to the substrate, and the thin film transistor is configured to control the quantum dot light emitting device of the sub-pixel unit to emit light.

Preferably, the quantum dot light emitting device is a blue quantum dot light emitting device; the blue quantum dot light emitting device comprises a cathode, an electron injection layer, and blue quantum dot light emitting a layer, a hole injection layer, and an anode; the anode is electrically connected to a drain of the thin film transistor.

Preferably, the second type of sub-pixel unit is a blue sub-pixel unit, and the first type of sub-pixel unit comprises a green sub-pixel unit and a red sub-pixel unit.

Preferably, the blue sub-pixel unit includes a transparent planarization layer adjacent to a side of the substrate substrate corresponding to the quantum dot light-emitting device; the light conversion structure of the green sub-pixel unit includes a green conversion layer and a green filter layer The light conversion structure of the red sub-pixel unit includes a red conversion layer and a red filter layer.

Preferably, the blue quantum dot luminescent layer has a thickness of 10 to 100 nm; the blue quantum dot luminescent layer uses a blue quantum dot material having a particle diameter of 1-10 nm; and the blue quantum dot material includes CdS or CdSn.

Preferably, the material of the red conversion layer comprises Sr _x Ca _1-x S:Eu, wherein 0≤x≤1; the material of the green conversion layer comprises SrGa ₂ S ₄ or YAG:Ce.

Preferably, the red conversion layer and the green conversion layer have a thickness of 1-10 um.

Another object of the present invention is to provide a method of fabricating a display substrate comprising the following steps:

Forming a light conversion structure corresponding to the first type of sub-pixel unit on the base substrate on which the thin film transistor array is formed;

Forming a quantum dot light-emitting device on the base substrate forming the light conversion structure, the quantum dot light-emitting device comprising a quantum dot light-emitting layer integrally formed with the same layer of the plurality of sub-pixel units;

Wherein the first type of sub-pixel unit is a sub-pixel unit having a color light wavelength greater than a color light wavelength of the quantum dot light-emitting layer; and the light conversion structure is configured to convert color light of the quantum dot light-emitting device into the first The color light corresponding to the sub-pixel unit.

Another object of the present invention is to provide a display device including the above display substrate.

The display substrate of the present invention, the preparation method thereof and the display device, since the light-emitting device in which the quantum dot light-emitting layer is located adopts the same quantum dot material, the quantum dot light-emitting layer is integrally disposed in the same layer, and the quantum dot light-emitting layer does not need to be patterned. Handle

The problem of color shift caused by the use of different quantum dot materials in the prior art.

DRAWINGS

1 is a schematic structural view of a quantum dot display substrate in Embodiment 1 of the present invention;

Description of the reference signs:

1. a substrate; 2. a gate; 3. a first insulating layer; 4. an active layer; 5. a second insulating layer; 6. a source; 7. a drain; 8. a first planarizing layer; Red filter layer; 10. red conversion layer; 11. green filter layer; 12. green conversion layer; 13. transparent planarization layer corresponding to blue sub-pixel unit; 14. transparent corresponding to red, green sub-pixel unit Flattening layer; 15. anode; 16. pixel defining layer; 17. hole injecting layer; 18. blue quantum dot emitting layer; 19. electron injecting layer; 20. cathode; 21. second planarizing layer; Cover plate; 23. pixel defining area; 24. light transmitting area; 25. sub-pixel unit.

detailed description

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example 1:

The embodiment provides a display substrate including a substrate substrate and a plurality of pixel units formed on the base substrate, each of the pixel units including a plurality of sub-pixel units.

Each of the sub-pixel units includes a quantum dot light emitting device away from a side of the substrate.

The quantum dot light emitting device includes a quantum dot light emitting layer, and the quantum dot light emitting layers corresponding to the plurality of sub pixel units are integrally disposed in the same layer;

A sub-pixel unit having a color light wavelength greater than a color light wavelength of the quantum dot light-emitting layer is referred to as a first-type sub-pixel unit. Also, a sub-pixel unit having a color light wavelength equal to a color light wavelength of the quantum dot light-emitting layer is referred to as a second-type sub-pixel unit.

The first type of sub-pixel unit includes a light conversion structure corresponding to a side of the substrate substrate corresponding to the quantum dot light-emitting device, and the light conversion structure is configured to convert color light emitted by the quantum dot light-emitting device into the first-type sub-pixel unit Corresponding color light.

In the display substrate of the embodiment, since the quantum dot light-emitting device uses the same quantum dot material, and the quantum dot light-emitting layer of the quantum dot light-emitting device is integrally disposed in the same pixel layer, the quantum dot light-emitting layer does not need to be patterned. The problem of color shift caused by the use of different quantum dot materials in the prior art is also avoided.

It should be understood that this embodiment is introduced in the bottom illumination mode, and other types of illumination modes are also applicable; this embodiment is described by taking the sub-pixel unit of the three primary colors of red, green and blue and the blue quantum dot illumination layer as an example, and other primary colors. The sub-pixel unit and the quantum dot luminescent layer of other colors are also applicable; wherein the color wavelength of the blue sub-pixel unit is equal to the color wavelength of the blue quantum dot luminescent layer, which is the second type of sub-pixel unit; red, green The color light wavelength of the sub-pixel unit is greater than the color light wavelength of the blue quantum dot light emitting layer, and is a first type of sub-pixel unit.

Specifically, the display substrate shown in FIG. 1 includes a substrate substrate 1 and a plurality of pixel units of a pixel region formed on the substrate substrate 1, each pixel unit including three sub-pixel units of red, green, and blue; Specifically, as shown in FIG. 1 , wherein the red and green sub-pixel units are the first type of sub-pixel units, and the green sub-pixel unit is located in the left portion of FIG. 1 (the following is not shown in FIG. 1 for the green sub-pixel unit; The pixel defining portion), the red sub-pixel unit is located in the middle portion of FIG. The blue sub-pixel unit is a second type of sub-pixel unit located in the right portion of FIG.

Each sub-pixel unit 25 includes a pixel defining area 23 and a light transmitting area 24 between the pixel defining area 23 of the sub-pixel unit 25 and the pixel defining area of the adjacent sub-pixel unit; each sub-pixel unit 25 Including a blue quantum dot light-emitting device remote from the side of the substrate 1 , the wavelength of light emitted by the blue quantum dot light-emitting device is equal to the wavelength of the color light of the blue sub-pixel unit, and the blue quantum dot light-emitting device includes blue quantum The light-emitting layer is arranged, and the blue quantum dot light-emitting layers corresponding to the red, green, and blue sub-pixel units are integrally disposed in the same layer. The light emitted by the blue quantum dot light-emitting device can be displayed in color by the above-described red, green, and blue sub-pixel units.

Each of the sub-pixel units 25 includes a thin film transistor on the side of the pixel defining region 23 close to the base substrate 1, and the thin film transistor is used to control the blue quantum dot light emitting device to emit light.

In the light-transmissive region 24 of the red, green sub-pixel unit, the blue quantum dot emits light A side of the device adjacent to the substrate 1 is provided with a light conversion structure that converts the color light of the quantum dot light-emitting device into a color light corresponding to the red and green sub-pixel units.

Specifically, the light conversion structure includes a color light conversion layer corresponding to the red and green sub-pixel units, and a color light filter layer, and the color light emitted from the quantum dot light emitting device passes through the color light conversion layer and the color light filter layer to become red and green sub-pixels. The color shade corresponding to the unit.

Specifically, as shown in FIG. 1, the blue quantum dot light emitting device includes an anode 15 sequentially disposed on the transparent planarization layer 13 of the corresponding blue sub-pixel unit or on the transparent planarization layer 14 corresponding to the red and green sub-pixel units. The hole injection layer 17, the blue quantum dot light-emitting layer 18, the electron injection layer 19, and the cathode 20. The anode 15 is electrically connected to the drain 7 of the corresponding thin film transistor. Among them, the blue quantum dot light-emitting layer 18 is formed by coating a mixture containing a blue quantum dot on the hole injection layer 17. Since the blue quantum dot light-emitting layer 18 of each sub-pixel unit is integrally provided in the same layer, it is not necessary to pattern the quantum dot light-emitting layer.

Specifically, the blue quantum dot light-emitting layer 18 has a thickness of 10 to 100 nm, which may be determined according to the light conversion efficiency and process capability of the quantum dot light-emitting layer.

The blue quantum dot material used in the blue quantum dot light-emitting layer 18 has a particle diameter of 1-10 nm. The blue quantum dot material may be a cadmium-based quantum dot material. Specifically, the blue quantum dot material may be CdS or CdSn.

Specifically, the blue sub-pixel unit includes a transparent planarization layer 13 on the side close to the substrate 1 corresponding to the quantum dot light-emitting device. Since the quantum dot light-emitting layer of the quantum dot light-emitting device uses a blue quantum dot material, and the color light wavelength of the blue sub-pixel unit is equal to the wavelength of the blue quantum dot material, the planarization layer 13 only needs to be made transparent. The layer is such that the light emitted by the blue quantum dot material can be directly transmitted. Specifically, the transparent planarizing layer 13 can be made of a transparent resin, for example, a transparent epoxy resin.

As shown in FIG. 1, the light conversion structure of the green sub-pixel unit includes a green conversion layer 12 and a green filter layer 11. The green conversion layer 12 is closer to the quantum dot light-emitting device than the green filter layer 11, such that the blue light emitted from the quantum dot light-emitting device is first converted into green light through the green conversion layer 12, and then filtered through the green filter layer 11. Part of the variegated light in the green light (eg, a small amount of unconverted blue light). Preferably, the material of the green conversion layer 12 includes SrGa ₂ S ₄ or YAG:Ce, and it should be understood that other green conversion materials in the prior art may also be selected.

As shown in FIG. 1, the light conversion structure of the red sub-pixel unit includes a red conversion layer 10 and a red filter layer 9. The red conversion layer 10 is closer to the quantum dot light-emitting device than the red filter layer 9, such that the blue light emitted from the quantum dot light-emitting device is first converted into red light by the red conversion layer 10, and then filtered through the red filter layer 9. Part of the variegated light in the red light (eg, a small amount of unconverted blue light). Preferably, the material of the red conversion layer 10 includes Sr _x Ca _1-x S:Eu, where 0≤x≤1, it should be understood that other red conversion materials in the prior art may also be selected.

It should be noted that, in the red conversion layer 10 and the green conversion layer 12 near the quantum dot light emitting device side (ie, above the red filter layer 9 and the green filter layer 11), transparent flats corresponding to the red and green sub-pixel units are disposed. The layer 14 is used to adjust the height of the light conversion structure in each sub-pixel.

Preferably, the red conversion layer 10 and the green conversion layer 12 described above have a thickness of 1-10 um. It can be selected according to the specific application scenario.

Further preferably, the red conversion layer 10 and the green conversion layer 12 have a thickness of 2-8 um. It can be selected according to the specific application scenario.

Preferably, the green filter layer 11 and the red filter layer 9 have a thickness of 1-5 um.

The structure of the thin film transistor is in the prior art. Typically, as shown in FIG. 1, the thin film transistor includes a gate electrode 2, a first insulating layer 3, an active layer 4, and a second insulating layer which are sequentially disposed on the base substrate 1. 5. Source 6, drain 7, and first planarization layer 8. It should be understood that the above thin film transistor can also adopt other structures in the prior art.

Example 2

This embodiment provides a method for fabricating the above display substrate, including the following steps:

Forming a quantum dot light-emitting device on a base substrate on which the light conversion structure is formed, the quantum dot light-emitting device including an amount of integral formation of a plurality of sub-pixel units Sub-point luminescent layer;

Specifically, the method for manufacturing the display substrate includes the following steps:

1. First, a thin film transistor structure is formed on the base substrate 1. As shown in FIG. 1, the gate electrode 2, the first insulating layer 3, the active layer 4, the second insulating layer 5, and the source electrode 6 are sequentially formed by a patterning process. The drain electrode 7, the first planarization layer 8, and the fabrication of the thin film transistor are in the prior art, and will not be further described herein.

2. Forming a red filter layer 9 on the first planarization layer 8 at a corresponding position of the red sub-pixel unit by a patterning process; forming a green filter layer 11 at a corresponding position of the green sub-pixel unit; preferably, the green filter The thickness of the light layer 11 and the red filter layer 9 is 1-5 um. It should be understood that the fabrication and material selection of the above-mentioned green filter layer 11 and red filter layer 9 are in the prior art, and will not be further described herein.

3. Forming a red conversion layer 10 on the red filter layer 9 by a patterning process; forming a green conversion layer 12 on the green filter layer 11; preferably, the thickness of the red conversion layer 10 and the green conversion layer 12 described above is 1- 10微米; further preferably, the red conversion layer 10 and the green conversion layer 12 have a thickness of 2-8 um; preferably, the material of the green conversion layer 12 includes SrGa ₂ S ₄ or YAG:Ce; the red conversion layer The material of 10 includes Sr _x Ca _1-x S:Eu, where 0 ≤ x ≤ 1.

It should be understood that the above-mentioned green filter layer 11 and red filter layer 9 are fabricated in the prior art, and will not be further described herein. The materials of the green filter layer 11 and the red filter layer 9 can also be made of other types of materials in the prior art.

4. forming a transparent planarization layer 13 corresponding to the blue sub-pixel unit at a corresponding position of the blue sub-pixel unit on the first planarization layer 8 by a patterning process, for example, an epoxy-based transparent resin;

A transparent planarization layer 14 corresponding to the red and green sub-pixel units is formed on the red conversion layer 10 and the green conversion layer 12 by a patterning process, the thickness of which is used to adjust the height of the light conversion structure in each sub-pixel unit.

5. On the transparent planarization layer 14 and the transparent planarization layer 13 by a patterning process An anode 15 is prepared; the anode 15 is connected to the drain 7 of the thin film transistor for controlling the anode 15 to be charged by the thin film transistor. The anode 15 is fabricated in the prior art and will not be further described herein.

6. Forming the pixel defining layer 16 by a patterning process, wherein the fabrication of the pixel defining layer 16 is in the prior art, and will not be further described herein.

7. The hole injection layer 17, the blue quantum dot light-emitting layer 18, the electron injection layer 19, and the cathode 20 are formed on the anode 15 in this order. It should be noted that the blue quantum dot light-emitting layer 18 may be spin-coated. A full layer coating is obtained. The blue quantum dot luminescent layer 18 has a thickness of 10-100 nm; the blue quantum dot luminescent layer 18 uses a blue quantum dot material having a particle diameter of 1-10 nm; and the blue quantum dot material is CdS or CdSn.

Other functional layers can be prepared by evaporation, and will not be further described herein.

Alternatively, the second planarization layer 21 can be continued and the cover 22 can be packaged. A display substrate as shown in FIG. 1 was obtained.

Example 3

The embodiment provides a display device including the above display substrate.

In the display substrate and the display device of the present invention, since the quantum dot light-emitting device is prepared by using the same quantum dot material, and the quantum dot light-emitting layer of the quantum dot light-emitting device is integrally disposed in the same layer, it is not necessary to pattern the quantum dot light-emitting layer. The problem of color shift caused by the use of different quantum dot materials in the prior art is also avoided.

The display device provided by the present invention can be used for any product or component having a display function such as a television, a mobile phone, a navigator or the like.

It is to be understood that the above embodiments are merely exemplary embodiments employed to explain the principles of the invention, but the invention is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and scope of the invention. These modifications and improvements are also considered to be within the scope of the invention.

Claims

A display substrate includes a substrate substrate and a plurality of pixel units formed on the substrate substrate, each pixel unit including a plurality of sub-pixel units; wherein

Each of the sub-pixel units includes a quantum dot light emitting device away from a side of the substrate;

The quantum dot light emitting device includes a quantum dot light emitting layer, and the quantum dot light emitting layers corresponding to the plurality of sub pixel unit are integrally disposed in the same layer;

The sub-pixel unit having a color light wavelength greater than a color light wavelength of the quantum dot light-emitting layer is a first type of sub-pixel unit, and the first type of sub-pixel unit includes light corresponding to a side of the substrate substrate corresponding to the quantum dot light-emitting device. And a conversion structure for converting color light emitted by the quantum dot light emitting device into color light corresponding to the first type of sub-pixel unit.
The display substrate according to claim 1, wherein the sub-pixel unit is further a second type of sub-pixel unit having a color light wavelength equal to a color light wavelength of the quantum dot light emitting layer.
The display substrate according to claim 2, wherein the first type of sub-pixel unit and the second type of sub-pixel unit comprise a transparent flat disposed on a side close to the substrate substrate corresponding to the quantum dot light-emitting device Layer.
The display substrate according to claim 1, wherein the light conversion structure comprises a color light conversion layer and a color light filter layer corresponding to the first type of sub-pixel unit, and the color light emitted by the quantum dot light emitting device is passed through The color light conversion layer and the color light filter layer are then converted into color lights corresponding to the first type of sub-pixel units.
The display substrate of claim 1, wherein each of the sub-pixel units comprises a pixel defining region and a light transmitting region, the light transmitting region being located in the pixel defining region and the pixel of the adjacent sub-pixel unit Defining between regions;

Each of the sub-pixel units includes a thin film transistor on a side of the pixel defining region adjacent to the substrate, and the thin film transistor is configured to control the quantum dot light emitting device of the sub-pixel unit to emit light.
The display substrate according to claim 5, wherein the quantum dot light emitting device is a blue quantum dot light emitting device; the blue quantum dot light emitting device comprises a cathode, an electron injecting layer, a blue quantum dot emitting layer, and a hole An injection layer and an anode; the anode is electrically connected to a drain of the thin film transistor.
The display substrate according to claim 2, wherein the second type of sub-pixel unit is a blue sub-pixel unit, and the first type of sub-pixel unit comprises a green sub-pixel unit and a red sub-pixel unit.
The display substrate according to claim 7, wherein the blue sub-pixel unit comprises a transparent planarization layer adjacent to a side of the substrate substrate corresponding to the quantum dot light-emitting device; and the light conversion structure of the green sub-pixel unit comprises a green conversion layer and a green filter layer; the light conversion structure of the red sub-pixel unit includes a red conversion layer and a red filter layer.
The display substrate according to claim 6, wherein the blue quantum dot light-emitting layer has a thickness of 10 to 100 nm; the blue quantum dot light-emitting layer uses a blue quantum dot material having a particle diameter of 1-10 nm; The blue quantum dot material includes CdS or CdSn.
The display substrate according to claim 8, wherein the material of the red conversion layer comprises Sr x Ca 1-x S:Eu, wherein 0 ≤ x ≤ 1; and the material of the green conversion layer comprises SrGa 2 S 4 Or YAG: Ce.
The display substrate according to claim 8, wherein the red conversion layer and the green conversion layer have a thickness of 1-10 um.
A method of manufacturing a display substrate, comprising the steps of:

Forming a light conversion structure corresponding to the first type of sub-pixel unit on the base substrate on which the thin film transistor array is formed;

Forming a quantum dot light-emitting device on the base substrate forming the light conversion structure, the quantum dot light-emitting device comprising a quantum dot light-emitting layer integrally formed with the same layer of the plurality of sub-pixel units;

Wherein the first type of sub-pixel unit is a sub-pixel unit having a color light wavelength greater than a color light wavelength of the quantum dot light emitting layer;

The light conversion structure is configured to convert color light of the quantum dot light emitting device into color light corresponding to the first type of sub-pixel unit.
A display device comprising the display substrate according to any one of claims 1-11.