WO2020220492A1

WO2020220492A1 - Pixel electrode structure and method for manufacturing pixel electrode structure

Info

Publication number: WO2020220492A1
Application number: PCT/CN2019/098479
Authority: WO
Inventors: 史婷
Original assignee: 深圳市华星光电半导体显示技术有限公司
Priority date: 2019-04-30
Filing date: 2019-07-31
Publication date: 2020-11-05
Also published as: CN110071159A; CN110071159B

Abstract

Disclosed are a pixel electrode structure and a method for manufacturing a pixel electrode structure. The pixel electrode structure comprises a pixel reflection electrode, a pixel definition layer, a hole inject layer, a hole transport layer, a light-emitting layer and a translucent layer, wherein the pixel reflection electrode comprises a red pixel reflection electrode, a green pixel reflection electrode and a blue pixel reflection electrode; and the distance between the red pixel reflection electrode and the green pixel reflection electrode is less than the distance between the green pixel reflection electrode and the blue pixel reflection electrode.

Description

Pixel electrode structure and manufacturing method of pixel electrode structure

Technical field

The present invention relates to the field of display technology, in particular to a pixel electrode structure with high resolution and a method for manufacturing the pixel electrode structure.

Background technique

Organic electroluminescent diodes (OLEDs) have become a key technology for the development of the display panel market due to their advantages of high brightness, self-luminescence, fast response, and low driving voltage. In large-size OLED display panels, the cathode of the bottom light-emitting structure uses thicker alkali metal, but the bottom light-emitting structure of the OLED display panel needs to penetrate the opaque transistors and data lines. The opening rate of the OLED display panel of the π structure is relatively low. As users have higher and higher requirements for resolution, the OLED display panel gradually focuses on the development of the top light emitting structure in order to achieve higher resolution.

technical problem

The top-emitting OLED structure uses a transparent conductive oxide or a thinner semi-transparent metal as the top cathode, and light is emitted from the top. The top-emitting OLED uses a metal microcavity structure to place the light-emitting area in a resonant cavity formed by a reflective electrode and a semi-reflective film. When the degree of the OLED is equivalent to the wavelength of the light, the OLED can enhance the light intensity through the microcavity effect of the resonance cavity. The light color of the device is purer and the efficiency is higher. In the development of high-resolution inkjet printing top-emitting devices, due to the small pixel size, if red (R, red), green (G, green), blue (B, blue) are made of conductive materials such as oxide smoke Pixel reflective electrodes are all based on the second node of the microcavity effect. The thickness of each layer of the device is large, and the risk of overflow and color mixing is likely to occur during printing. If the concentration is increased, it will be difficult to eject ink. Using the first node of the microcavity effect as a reference, the red and green pixel reflective electrodes can be easily fabricated, but due to the shorter blue wavelength, the hole injection layer (HIL, Hole Inject Layer) and hole transport layer in the first node device structure (HTL, Hole Transport The thickness of the layer is only a dozen nanometers, making the manufacturing process difficult.

Therefore, the present invention provides a pixel electrode structure and a manufacturing method of the pixel electrode structure. The top-emitting OLED display panel using inkjet printing can have a high-resolution OLED display panel.

Technical solutions

The present invention provides a pixel electrode structure including a pixel reflective electrode, a pixel defining layer, a hole injection layer, a hole transport layer, a light-emitting layer and a semi-transparent layer. The pixel reflective electrode includes a red pixel reflective electrode, a green pixel reflective electrode and a blue pixel reflective electrode. The pixel defining layer is arranged between the pixel reflective electrodes. The hole injection layer is disposed on the pixel reflective electrode. The hole transport layer is disposed on the hole injection layer. The light-emitting layer is disposed on the hole transport layer. The translucent layer is disposed on the light-emitting layer. The distance between the red pixel reflective electrode and the green pixel reflective electrode is smaller than the distance between one of the green pixel reflective electrode and the red pixel reflective electrode and the blue pixel reflective electrode. The pixel definition layer between the red pixel reflective electrode and the green pixel reflective electrode has a first width, and the pixel between the green pixel reflective electrode and the blue pixel reflective electrode The definition layer has a second width, and the pixel definition layer between the blue pixel reflective electrode and the red pixel reflective electrode has a third width, wherein the first width is smaller than the second width, the The first width is smaller than the third width. The thickness of the hole injection layer on the blue pixel reflective electrode is greater than the thickness of the hole injection layer on the red pixel reflective electrode and the green pixel reflective electrode.

Preferably, the thickness of the hole transport layer on the blue pixel reflective electrode is greater than the thickness of the hole transport layer on the red pixel reflective electrode and the green pixel reflective electrode.

Preferably, the thickness of the hole injection layer on the blue pixel reflective electrode is greater than 60 nanometers, and the thickness of the hole transport layer on the blue pixel reflective electrode is greater than 60 nanometers.

Preferably, the second width is equal to the third width, the first width is 10 nanometers, and the second width and the third width are 20 nanometers.

The present invention provides a pixel electrode structure including a pixel reflective electrode, a pixel defining layer, a hole injection layer, a hole transport layer, a light-emitting layer and a semi-transparent layer. The pixel reflective electrode includes a red pixel reflective electrode, a green pixel reflective electrode and a blue pixel reflective electrode. The pixel defining layer is arranged between the pixel reflective electrodes. The hole injection layer is disposed on the pixel reflective electrode. The hole transport layer is disposed on the hole injection layer. The light-emitting layer is disposed on the hole transport layer. The translucent layer is disposed on the light-emitting layer. The distance between the red pixel reflective electrode and the green pixel reflective electrode is smaller than the distance between one of the green pixel reflective electrode and the red pixel reflective electrode and the blue pixel reflective electrode.

Preferably, the pixel defining layer between the red pixel reflective electrode and the green pixel reflective electrode has a first width, and the width between the green pixel reflective electrode and the blue pixel reflective electrode The pixel definition layer has a second width, and the pixel definition layer between the blue pixel reflective electrode and the red pixel reflective electrode has a third width, wherein the first width is smaller than the second width , The first width is smaller than the third width.

Preferably, the thickness of the hole injection layer located on the blue pixel reflective electrode is greater than the thickness of the hole injection layer located on the red pixel reflective electrode and the green pixel reflective electrode. The thickness of the hole transport layer on the blue pixel reflective electrode is greater than the thickness of the hole transport layer on the red pixel reflective electrode and the green pixel reflective electrode.

The present invention also provides a method for manufacturing a pixel electrode structure, including forming a hole injection layer, a hole transport layer, and a light-emitting layer on the pixel reflective electrode by inkjet printing, and forming a translucent layer on the light-emitting layer by an evaporation process Floor. Wherein the pixel reflective electrode includes a red pixel reflective electrode, a green pixel reflective electrode, and a blue pixel reflective electrode, and the spacing between the red pixel reflective electrode and the green pixel reflective electrode is smaller than the green pixel reflective electrode and the blue pixel reflective electrode. The spacing between pixel reflective electrodes.

Preferably, there is a first gap between the red pixel reflective electrode and the green pixel reflective electrode, and there is a second gap between the green pixel reflective electrode and the blue pixel reflective electrode, and the blue pixel reflective electrode There is a third distance between the reflective electrode and the red pixel, wherein the first distance is smaller than the second distance, and the first distance is smaller than the third distance.

Preferably, the thickness of the hole injection layer located on the blue pixel reflective electrode is greater than the thickness of the hole injection layer located on the red pixel reflective electrode and the green pixel reflective electrode, which is located on the blue pixel The thickness of the hole transport layer on the reflective electrode is greater than the thickness of the hole transport layer on the red pixel reflective electrode and the green pixel reflective electrode.

Preferably, the second pitch is equal to the third pitch, the first pitch is 10 nanometers, and the second pitch and the third pitch are 20 nanometers.

Beneficial effect

The pixel electrode structure and the method for manufacturing the pixel electrode structure of the present invention can produce high-resolution pixel electrodes through inkjet printing.

Description of the drawings

FIG. 1 is a schematic structural diagram of a pixel electrode structure according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of the pixel position of the pixel electrode structure of the embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a pixel electrode structure according to an embodiment of the invention.

The best mode of the invention

The pixel electrode structure and the manufacturing method of the pixel electrode structure provided by the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

Please refer to FIG. 1, which is a schematic diagram of a pixel electrode structure according to an embodiment of the present invention. The pixel electrode structure 10 of the embodiment of the present invention includes a red pixel reflective electrode 102, a green pixel reflective electrode 104, and a blue pixel reflective electrode 106. The substrate 12 and the pixel definition layer 14. The red pixel reflective electrode 102, the green pixel reflective electrode 104 and the blue pixel reflective electrode 106 are separated by the pixel defining layer 14. The width of the pixel defining layer between the red pixel reflective electrode 102 and the green pixel reflective electrode 104 is L1, and the green pixel The width between the reflective electrode 104 and the blue pixel reflective electrode 106 is L2, and the width L2 is greater than the width L1. That is, the distance between the blue pixel reflective electrode 106 and the green pixel reflective electrode 104 is greater than the distance between the red pixel reflective electrode 102 and the green pixel reflective electrode 104. The material of the pixel definition layer 14 may be epoxy resin and other materials that are not easily conductive. Preferably, the pixel definition layer is hydrophobic, with a height of 0.2-5 nanometers (nm, nanometer), and an inclination angle of 10-80 degrees. The surface tension is between 10-14mN/m.

2 is a schematic diagram of the pixel position of the pixel electrode of the present invention. As shown in FIG. 2, the distance between the red pixel reflective electrode 102 and the green pixel reflective electrode 104 is L1, and the green pixel reflective electrode 104 and the blue pixel reflective electrode 106 are L2, where L2 is greater than L1. Furthermore, the distance between the blue pixel reflective electrode 106 and the red pixel reflective electrode 102 is also L2, which means that the distance between the blue pixel reflective electrode 106 and other pixel reflective electrodes is larger than the red pixel reflective electrode 102 and the green pixel reflective electrode The spacing between 104. In addition, the width of the red pixel reflective electrode 102 is LR, the width of the green pixel reflective electrode 104 is LG, the width of the blue pixel reflective electrode 106 is LB, and the width LB of the blue pixel reflective electrode 106 is greater than the width LR of the red pixel reflective electrode 102. At the same time, the width LB of the blue pixel reflective electrode 106 is greater than the width LG of the green pixel reflective electrode 104. In a preferred embodiment of the present invention, L1 is 10 nanometers and L2 is 20 nanometers.

FIG. 3 is a schematic diagram showing the detailed structure of the pixel electrode of the present invention. As shown in FIG. 3, the red pixel reflective electrode 102, the green pixel reflective electrode 104, and the blue pixel reflective electrode 106 are disposed on the substrate 12. There are pixels between the red pixel reflective electrode 102, the green pixel reflective electrode 104 and the blue pixel reflective electrode 106. The definition layer 14 separates pixel electrodes of different colors to avoid color mixing. On the red pixel reflective electrode 102, the green pixel reflective electrode 104, and the blue pixel reflective electrode 106, a hole injection layer (HIL, Hole Inject Layer) 32, a hole transport layer (HTL, Hole Transport Layer) are sequentially formed by an inkjet printing process ) 34 and a light-emitting layer (EML, Emitting layer) 36. In a preferred embodiment of the present invention, the red pixel reflective electrode 102, the green pixel reflective electrode 104 and the blue pixel reflective electrode 106 are composed of silver-indium tin oxide (Ag/ITO). Preferably, the thickness of the silver is 150 nanometers. , The thickness of indium tin oxide is 15 nanometers.

After the hole injection layer 32, the hole transport layer 34, and the light emitting layer 36 are formed, the translucent layer 38 is formed by an evaporation process. The translucent layer 38 has an electron transport layer (ETL, Electron transport layer) 382, a semi-transparent cathode Anode) 384 and protective layer (CPL, capping layer) 386, the material of the translucent cathode and anode can be magnesium silver (Mg:Ag) alloy. Since the wavelength of each color light is different, the suitable thickness of each layer in the pixel electrode structure is also different. In a preferred embodiment of the present invention, the hole injection layer 32, the hole transport layer 34, and the light emitting layer are formed on the red pixel reflective electrode 102. Suitable thicknesses of layer 36, electron transport layer 382, semi-transparent cathode and anode 384, and protective layer 386 are 30-40 nanometers, 20 nanometers, 50-60 nanometers, 30 nanometers, 20 nanometers, and 60 nanometers, respectively, which are formed on the green pixel reflection The hole injection layer 32, the hole transport layer 34, the light-emitting layer 36, the electron transport layer 382, the semi-transparent cathode and anode 384 and the protective layer 386 on the electrode 104 have suitable thicknesses of 20-30 nanometers, <15 nanometers, and 40 nanometers, respectively. -50 nm, 30 nm, 20 nm and 60 nm, the hole injection layer 32, the hole transport layer 34, the light emitting layer 36, the electron transport layer 382, the translucent cathode and anode 384 and the protective layer formed on the blue pixel reflective electrode Suitable thicknesses of 386 are 60-80 nanometers, 80-90 nanometers, 50-60 nanometers, 30 nanometers, 20 nanometers and 60 nanometers. However, the above-mentioned more suitable thickness is only an example and is not intended to limit the present invention. Those skilled in the art, based on the pixel structure thickness of the embodiment of the present invention, will adjust the thickness in order to make the OLED have good light transmittance. The scope of the invention.

The pixel electrode structure of the present invention is composed of a pixel reflective electrode, a hole injection layer, a hole transport layer, a light-emitting layer and a semi-transparent layer. That is, the red pixel electrode is composed of a red pixel reflective electrode, a hole injection layer, a hole transport layer, The light-emitting layer and the semi-transparent layer are composed of the green pixel electrode and the blue pixel electrode. The red pixel electrode and the green pixel electrode adopt the first microcavity node device structure, and the blue pixel electrode adopts the second micro node device structure. Since the hole injection layer and the hole transport layer on the blue pixel electrode have a thickness of more than 60 nanometers, Overflow is prone to occur during the manufacturing process. By widening the distance between the blue pixel electrode and other pixel electrodes (that is, L2 is greater than L1), the color mixing of the pixel electrode can be effectively avoided.

Compared with the pixel electrode structure in the prior art, the pixel electrode structure of the present invention uses the first microcavity node device structure to form the red pixel electrode and the green pixel electrode, and the second microcavity node device structure to form the blue pixel electrode. The spacing between the wide blue pixel electrode and the pixel electrodes of other colors prevents color mixing of the pixel electrodes. Therefore, the pixel electrode structure and the method for manufacturing the pixel electrode structure of the present invention can produce high-resolution pixel electrodes through inkjet printing.

Through the pixel electrode structure and manufacturing method described in the embodiments of the present invention, the aperture ratio and light transmittance of the pixel electrode are improved. The above are only preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, Without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

A pixel electrode structure includes:

A plurality of pixel reflective electrodes, including a red pixel reflective electrode, a green pixel reflective electrode and a blue pixel reflective electrode;

A plurality of pixel defining layers are arranged between the pixel reflective electrodes;

The hole injection layer is arranged on the pixel reflective electrode;

The hole transport layer is arranged on the hole injection layer;

A light-emitting layer disposed on the hole transport layer; and

A semi-transparent layer disposed on the pixel definition layer and the light-emitting layer;

Wherein the distance between the red pixel reflective electrode and the green pixel reflective electrode is smaller than the distance between one of the green pixel reflective electrode and the red pixel reflective electrode and the blue pixel reflective electrode;

The pixel definition layer between the red pixel reflective electrode and the green pixel reflective electrode has a first width, and the pixel between the green pixel reflective electrode and the blue pixel reflective electrode The definition layer has a second width, and the pixel definition layer between the blue pixel reflective electrode and the red pixel reflective electrode has a third width, wherein the first width is smaller than the second width, the The first width is smaller than the third width; and

The thickness of the hole injection layer on the blue pixel reflective electrode is greater than the thickness of the hole injection layer on the red pixel reflective electrode and the green pixel reflective electrode.
The pixel electrode structure according to claim 1, wherein the thickness of the hole transport layer on the blue pixel reflective electrode is greater than the holes on the red pixel reflective electrode and the green pixel reflective electrode The thickness of the transmission layer.
3. The pixel electrode structure of claim 2, wherein the thickness of the hole injection layer on the blue pixel reflective electrode is greater than 60 nanometers, and the thickness of the hole transport layer on the blue pixel reflective electrode More than 60 nanometers.
3. The pixel electrode structure of claim 1, wherein the second width is equal to the third width, the first width is 10 nanometers, and the second width and the third width are 20 nanometers.
A pixel electrode structure includes:

A plurality of pixel reflective electrodes, including a red pixel reflective electrode, a green pixel reflective electrode and a blue pixel reflective electrode;

A plurality of pixel defining layers are arranged between the pixel reflective electrodes;

The hole injection layer is arranged on the pixel reflective electrode;

The hole transport layer is arranged on the hole injection layer;

A light-emitting layer disposed on the hole transport layer; and

A semi-transparent layer disposed on the pixel definition layer and the light-emitting layer;

The distance between the red pixel reflective electrode and the green pixel reflective electrode is smaller than the distance between one of the green pixel reflective electrode and the red pixel reflective electrode and the blue pixel reflective electrode.
5. The pixel electrode structure of claim 5, wherein the pixel definition layer between the red pixel reflective electrode and the green pixel reflective electrode has a first width, and is between the green pixel reflective electrode and the green pixel reflective electrode. The pixel definition layer between the blue pixel reflective electrodes has a second width, and the pixel definition layer between the blue pixel reflective electrodes and the red pixel reflective electrodes has a third width, wherein the A width is smaller than the second width, and the first width is smaller than the third width.
5. The pixel electrode structure according to claim 5, wherein the thickness of the hole injection layer on the blue pixel reflective electrode is greater than the holes on the red pixel reflective electrode and the green pixel reflective electrode The thickness of the injection layer is that the thickness of the hole transport layer on the blue pixel reflective electrode is greater than the thickness of the hole transport layer on the red pixel reflective electrode and the green pixel reflective electrode.
7. The pixel electrode structure according to claim 7, wherein the thickness of the hole injection layer on the blue pixel reflective electrode is greater than 60 nanometers, and the thickness of the hole transport layer on the blue pixel reflective electrode More than 60 nanometers.
7. The pixel electrode structure of claim 6, wherein the second width is equal to the third width, the first width is 10 nanometers, and the second width and the third width are 20 nanometers.
A method for manufacturing a pixel electrode structure includes:

Using inkjet printing to sequentially form a hole injection layer, a hole transport layer, and a light emitting layer on the pixel reflective electrode;

Forming a translucent layer on the light-emitting layer by using an evaporation process;

Wherein the pixel reflective electrode includes a red pixel reflective electrode, a green pixel reflective electrode, and a blue pixel reflective electrode, and the spacing between the red pixel reflective electrode and the green pixel reflective electrode is smaller than the green pixel reflective electrode and the blue pixel reflective electrode. The spacing between pixel reflective electrodes.
The method for manufacturing a pixel electrode structure according to claim 10, wherein a first distance is provided between the red pixel reflective electrode and the green pixel reflective electrode, and the green pixel reflective electrode and the blue pixel reflective electrode are provided between In the second pitch, there is a third pitch between the blue pixel reflective electrode and the red pixel reflective electrode, wherein the first pitch is smaller than the second pitch, and the first pitch is smaller than the third pitch.
10. The method for manufacturing a pixel electrode structure according to claim 10, wherein the thickness of the hole injection layer on the blue pixel reflective electrode is greater than the holes on the red pixel reflective electrode and the green pixel reflective electrode The thickness of the injection layer is that the thickness of the hole transport layer on the blue pixel reflective electrode is greater than the thickness of the hole transport layer on the red pixel reflective electrode and the green pixel reflective electrode.
10. The method for fabricating a pixel electrode structure according to claim 10, wherein the hole injection layer on the blue pixel reflective electrode has a thickness greater than 60 nanometers, and the hole transport layer on the blue pixel reflective electrode The thickness is greater than 60 nanometers.
11. The method for fabricating a pixel electrode structure according to claim 11, wherein the second pitch is equal to the third pitch, the first pitch is 10 nanometers, and the second pitch and the third pitch are 20 nanometers.