Silicon-based OLED micro-display strong microcavity anode structure and preparation method, and silicon-based OLED display device

Abstract

This invention discloses a strong microcavity anode structure for a silicon-based OLED microdisplay, comprising an anode metal layer, a microcavity structure layer, and a pixel definition layer sequentially disposed therefrom. The microcavity structure layer includes a microcavity isolation region, a metal connection layer with reflective function, and a microcavity adjustment layer. The metal connection layer is in contact with the anode metal layer and the conductive layer. The pixel definition layer includes a pixel isolation region and a pixel opening region. In this silicon-based OLED microdisplay strong microcavity anode structure, the metal connection layer disposed in the microcavity isolation region has a reflective effect, which can isolate optical crosstalk between adjacent pixels. This invention also discloses a method for fabricating the strong microcavity anode structure for a silicon-based OLED microdisplay and a silicon-based OLED display device.

Description

Technical Field

[0001] This invention belongs to the field of optical display technology. Specifically, this invention relates to a silicon-based OLED microdisplay with a strong microcavity anode structure and its fabrication method, and a silicon-based OLED display device. Background Technology

[0002] Micro OLED (Micro-Organic Light-Emitting Diode) displays have advantages such as small size, light weight, high contrast, fast response speed and low power consumption. In recent years, they have been widely used as near-eye displays in the fields of virtual reality (VR) and augmented reality (AR).

[0003] Traditional Micro OLEDs face significant challenges in light extraction efficiency. Due to their tiny size and compact structure, light generated in the organic material layers is subject to various limitations during its outward emission. For example, inside the device, light undergoes total internal reflection due to the refractive index difference at the interfaces between the organic layer and electrodes, encapsulation layers, etc., resulting in a large amount of light being trapped inside the device and unable to escape effectively, leading to relatively weak observable light intensity. This not only reduces the luminous efficiency of Micro OLEDs and increases power consumption but also limits their further expansion in applications requiring high brightness.

[0004] To address the aforementioned issues of traditional Micro OLEDs, strong microcavity technology has emerged. Strong microcavities can effectively control the light field through precise design of the cavity structure and optical properties. Introducing strong microcavities into Micro OLEDs can alter the propagation path and mode distribution of light within the device, increasing the emission probability of light in specific directions and thus improving light extraction efficiency. For example, by appropriately selecting parameters such as cavity length and mirror reflectivity, the cavity mode can be matched with the spontaneous emission mode of the emissive layer, achieving the so-called "cavity enhancement effect." This promotes the efficient emission of more photons from the device, thereby improving the overall performance of Micro OLEDs, such as increased brightness and reduced power consumption.

[0005] Existing strong microcavity structures use ITO material as the microcavity conditioning layer. ITO has a certain light absorption coefficient, which affects the maximum brightness. Furthermore, since both ITO and SiO materials have high transmittance, they cannot isolate optical crosstalk between pixels.

[0006] A strong microcavity anode structure for silicon-based OLED microdisplays is provided, particularly regarding how to isolate optical crosstalk between adjacent pixels and increase optical brightness. Summary of the Invention

[0007] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention provides a strong microcavity anode structure for silicon-based OLED microdisplays, with the purpose of isolating optical crosstalk between adjacent pixels.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a silicon-based OLED microdisplay with a strong microcavity anode structure, comprising an anode metal layer, a microcavity structure layer and a pixel definition layer arranged sequentially. The microcavity structure layer includes a microcavity isolation region, a metal connection layer with reflective function and a microcavity adjustment region. The metal connection layer is in contact with the anode metal layer and the conductive layer. The pixel definition layer includes a pixel isolation region and a pixel opening region.

[0009] The metal bonding layer is a composite film formed of Ti / TiN / Al / TiN or Ti / TiN / Ag / TiN.

[0010] The metal bonding layer is disposed around the microcavity isolation region.

[0011] The microcavity isolation region is a SiO layer.

[0012] The conductive layer is made of ITO.

[0013] The isolation zone is provided in multiple ways, and the height of the multiple microcavity isolation zones arranged continuously along a set direction changes in a step-like manner.

[0014] The present invention also provides a silicon-based OLED display device, including a driving circuit substrate, an anode metal layer and the silicon-based OLED microdisplay strong microcavity anode structure, wherein the pixel definition layer is disposed on the anode metal layer.

[0015] This invention also provides a method for fabricating a strong microcavity anode structure for a silicon-based OLED microdisplay, comprising the following steps:

[0016] S1. Provide a driving circuit substrate;

[0017] S2. An anode metal layer is formed on one side of the driving circuit substrate;

[0018] S3. A microcavity structure layer is formed on the side of the anode metal layer away from the driving circuit substrate;

[0019] S4. A pixel definition layer is formed on the side of the microcavity structure layer away from the driving circuit substrate; and a pixel opening area and a pixel isolation area are formed on the pixel definition layer.

[0020] The pixel isolation region is a stacked structure formed by SiO layer, SiN layer and SiO layer, with the SiN layer located between two SiO layers.

[0021] The silicon-based OLED microdisplay strong microcavity anode structure of the present invention has a metal interconnect layer in the microcavity isolation region that has a reflective effect, which can isolate the optical crosstalk between adjacent pixels. Attached Figure Description

[0022] This manual includes the following figures, which illustrate the following:

[0023] Figure 1 This is a schematic diagram of the strong microcavity anode structure of the silicon-based OLED microdisplay of the present invention;

[0024] Figures 2-11 This is a schematic diagram illustrating the fabrication process of the strong microcavity anode structure for a silicon-based OLED microdisplay.

[0025] The diagram is marked as follows:

[0026] 1. Driving circuit substrate; 2. Anode metal layer; 3. Microcavity isolation region; 4. Microcavity adjustment region; 5. Metal interconnect layer; 6. Conductive layer; 7. Pixel insulating layer; 8. Planarization region; 9. Metal interconnect layer; 10. Morphology of microcavity isolation region before etching; 11. Morphology of microcavity adjustment region before etching; 12. Second metal layer; 13. Etched region; 14. Insulating material; 15. Undercut structure. Detailed Implementation

[0027] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, in order to help those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solutions of the present invention, and to facilitate its implementation.

[0028] It should be noted that in the following embodiments, the terms "first," "second," and "third" do not represent an absolute distinction in structure and / or function, nor do they represent the order of execution; they are merely for the convenience of description.

[0029] Firstly, such as Figure 1 As shown, this embodiment of the invention provides a silicon-based OLED microdisplay with a strong microcavity anode structure, including an anode metal layer 2 and a microcavity structure layer arranged sequentially. The microcavity structure layer includes a microcavity isolation region 3 and a microcavity adjustment layer. The microcavity adjustment layer includes a conductive layer 6, a microcavity adjustment region 4, and a metal connection layer 5 disposed between the microcavity isolation region 3 and the microcavity adjustment region 4 and having a reflective function. The metal connection layer 5 is in contact with the anode metal layer 2 and the conductive layer 6, and the microcavity isolation region 3 is in contact with the anode metal layer 2 and the conductive layer 6.

[0030] Specifically, such as Figure 1As shown, multiple microcavity isolation regions 3 are arranged continuously along a set direction, and the height of these multiple microcavity isolation regions 3 changes in a step-like manner, with the height gradually decreasing along the set direction. The height of the microcavity isolation regions 3 varies at different positions along this set direction. This structure allows for the formation of a strong microcavity optical adjustment region using different step heights, which can narrow the half-width peak and improve device brightness.

[0031] In this embodiment of the invention, the microcavity isolation region 3 is a SiO layer.

[0032] like Figure 1 As shown, the pixel definition layer in the OLED structure is mainly used to isolate electrical crosstalk between adjacent pixels. The pixel definition layer is disposed on the microcavity structure layer, and the anode metal layer 2 is disposed on the driving circuit substrate 1. The pixel definition layer has multiple pixel opening regions corresponding to the anode metal layer 2, and the pixel definition layer has multiple pixel isolation regions 7. An isolation region 7 is disposed between two adjacent pixel opening regions.

[0033] like Figure 1 As shown, in this embodiment of the invention, a metal interconnect layer 5 is disposed around the microcavity isolation region 3. The metal interconnect layer 5 is a composite film layer formed of Ti / TiN / Al / TiN or Ti / TiN / Ag / TiN.

[0034] like Figure 1 As shown, in this embodiment of the invention, the conductive layer 6 is located on the side of the filling portion away from the driving circuit substrate 1. The conductive layer 6 is in contact with the top surface of the filling portion and the top surface of the metal connection layer 5, and the side surface of the filling portion is in contact with the side surface of the metal connection layer 5. The conductive layer 6 covers the filling portion. The material of the conductive layer 6 is ITO.

[0035] like Figure 1 As shown, in this embodiment of the invention, an insulating layer 7 is formed on the side of the pixel definition layer away from the driving circuit substrate 1. The insulating layer 7 is in contact with the conductive layer 6, the isolation region 3, and the metal connection layer 5. The insulating layer 7 is a stacked structure formed by SiO layer, SiN layer, and SiO layer, with the SiN layer located between the two SiO layers.

[0036] like Figure 1 As shown, a notch area is provided on the top surface of the metal connection layer 5, the microcavity isolation region 3 is located below the notch area, the insulating layer 7 is embedded in the notch area and contacts the top surface of the isolation region 3 below, the bottom surfaces of the metal connection layer 5 and the isolation region 3 are in contact with the anode metal layer 2, and the metal connection layer 5 is used for conduction.

[0037] In this embodiment of the invention, an optical pad layer area is defined by depositing isolation regions 3 between the microcavity regions. A metal interconnect layer 5 is disposed on the isolation regions 3 to connect with the underlying metal for conductivity. This structure can reduce non-light-emitting areas and increase the aperture ratio of the pixel definition layer. The increased aperture ratio means that more light can be emitted from the pixel. The use of SiO2 (SIN or SiO2+SIN) as the optical pad layer in the filling part, compared with the use of ITO as the pad layer in the prior art, reduces the absorption loss of light during transmission and improves the optical brightness of the display device. At the same time, the metal interconnect layer 5 disposed around the microcavity pad layer has a reflective effect. The reflective effect of the metal interconnect layer 5 effectively prevents light leakage to adjacent pixels and ensures that the light signal of each pixel is independent. It can isolate the optical crosstalk between adjacent pixels, thereby improving the image clarity and contrast.

[0038] Secondly, such as Figure 1 As shown, this embodiment of the invention also provides a silicon-based OLED display device, including a driving circuit substrate 1, an anode metal layer 2, and a silicon-based OLED microdisplay strong microcavity anode structure with the above-described structure, wherein a pixel definition layer is disposed on the anode metal layer 2.

[0039] Thirdly, embodiments of the present invention also provide a method for fabricating a strong microcavity anode structure for a silicon-based OLED microdisplay, comprising the following steps:

[0040] S1. Provide a driving circuit substrate 1;

[0041] S2. An anode metal layer 2 is formed on one side of the driving circuit substrate 1;

[0042] S3. A microcavity structure layer is formed on the side of the anode metal layer away from the driving circuit substrate;

[0043] S4. A pixel definition layer is formed on the side of the microcavity structure layer away from the driving circuit substrate; and a pixel opening area and a pixel isolation area are formed on the pixel definition layer.

[0044] S5. An insulating layer 7 is formed on the pixel definition layer, and the insulating layer 7 is in contact with the conductive layer 6.

[0045] In step S2 above, as Figure 2 As shown, TI / TIN / AL / TIN metal conductive layers are deposited sequentially using PVD (physical vapor deposition) equipment, and metal conductive pixels are fabricated through photolithography and etching steps. Then, SiOx (silicon dioxide) is deposited using PECVD (plasma-enhanced chemical vapor deposition), and planarization is performed using CMP (chemical mechanical polishing) or ETCH (etching) to finally form the anode metal layer 2.

[0046] Step S3 above includes:

[0047] S301. On the side of the anode metal layer 2 away from the driving circuit substrate 1, SiOx layers 10 of different heights are formed.

[0048] S302. Microcavity isolation region 3 and microcavity adjustment region 4 are formed on SiOx layers 10 at different heights;

[0049] S303, Form the first metal layer 9;

[0050] S304, Formation of the microcavity structure layer 11 before etching;

[0051] S305, forming the filling portion of the filling microcavity adjustment region 4;

[0052] S306, Form the second metal layer 12;

[0053] S308. Etch the second metal layer 12 to expose part of the top surface of the isolation region 3;

[0054] S309, Forming an insulating layer 7;

[0055] S310, Create the undercut structure of the pixel definition layer.

[0056] In step S301 above, as Figure 3 As shown, a SiOx thin film is deposited on the anode metal layer 2 using PECVD. Through photolithography and etching steps, the SiOx thin film is retained between one pixel and two pixels, while the SiOx thin film in the remaining areas is etched away. A SiOx thin film is deposited again using PECVD on the remaining structure to cover and protect the existing pattern. Again, through photolithography and etching steps, the SiOx thin film is retained between one pixel and two pixels. A third SiOx thin film is deposited using PECVD. Due to the deposition stacking, the SiOx thin film forms different heights in the specified areas, forming SiOx layers 10 of different heights. The height dimensions of the SiOx layers 10 at different locations on the anode metal layer 2 are different.

[0057] In step S302 above, as Figure 4 As shown, microcavity isolation region 3 and microcavity adjustment region 4 are formed on SiOx layers 10 of different heights using photolithography and plasma etching processes.

[0058] In step S303 above, as Figure 5 As shown, a first metal layer 9 is deposited on the entire surface using PVD. The first metal layer 9 is a composite film layer formed by Ti / TiN / Al / TiN or Ti / TiN / Ag / TiN. The first metal layer 9 covers the microcavity isolation region 3 and the microcavity adjustment region 4.

[0059] In step S304 above, as Figure 6As shown, a SiOx film is deposited across the entire surface using PECVD. The thickness of the SiOx film is the highest point of the microcavity isolation region 3 to ensure good isolation performance, ultimately forming the microcavity structure layer 11 before etching. The microcavity structure layer 11 before etching covers the first metal layer 9. The height of the microcavity structure layer 11 before etching varies for different heights of the microcavity isolation region 3.

[0060] In step S305 above, such as Figure 7 As shown, the microcavity structure layer 11 before etching undergoes three photolithography and etching steps until etching reaches the top surface of the isolation region 3, forming a filling portion that fills each microcavity adjustment region 4.

[0061] In step S306 above, such as Figure 8 As shown, a second metal layer 12 is deposited across the entire surface using PVD. The second metal layer 12 is an ITO film layer, which covers the first metal layer 9 and the microcavity adjustment region 4. Indium tin oxide (ITO) is deposited as a transparent conductive layer, as ITO has good conductivity and transparency.

[0062] In step S307 above, photolithography is used to etch the first metal layer and the second metal layer 12 located above the isolation region 3, exposing a portion of the top surface of the isolation region 3. The remaining first metal layer forms a metal interconnect layer, and the remaining second metal layer 12 forms a conductive layer 6. The etched area 13 is as follows: Figure 9 As shown in the image.

[0063] In step S308 above, such as Figure 10 As shown, an insulating layer 7 is deposited on the entire surface using CVD. The insulating layer 7 is a stacked structure formed by SiO layer, SiN layer and SiO layer, with the SiN layer located between the two SiO layers. The insulating layer 7 covers the conductive layer 6 and the isolation region 3.

[0064] In step S309 above, such as Figure 11 As shown, an undercut structure 15 of the pixel definition layer (PDL) is fabricated on the insulating layer 7 through photolithography and etching steps. This structure can precisely define the light-emitting area and isolate the current path, preventing current leakage and optical crosstalk.

[0065] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution; or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A silicon-based OLED microdisplay with a strong microcavity anode structure, characterized in that, It includes an anode metal layer, a microcavity structure layer and a pixel definition layer arranged sequentially. The microcavity structure layer includes a microcavity isolation region, a metal connection layer with reflective function and a microcavity adjustment region. The metal connection layer is in contact with the anode metal layer and the conductive layer. The pixel definition layer includes a pixel isolation region and a pixel opening region.

2. The silicon-based OLED microdisplay strong microcavity anode structure according to claim 1, characterized in that, The metal bonding layer is a composite film formed of Ti / TiN / Al / TiN or Ti / TiN / Ag / TiN.

3. The silicon-based OLED microdisplay strong microcavity anode structure according to claim 1, characterized in that, The metal bonding layer is disposed around the microcavity isolation region.

4. The silicon-based OLED microdisplay strong microcavity anode structure according to any one of claims 1 to 3, characterized in that, The microcavity isolation region is a SiO layer.

5. The silicon-based OLED microdisplay strong microcavity anode structure according to any one of claims 1 to 3, characterized in that, The conductive layer is made of ITO.

6. The silicon-based OLED microdisplay strong microcavity anode structure according to any one of claims 1 to 3, characterized in that, Multiple microcavity isolation regions are provided, and the height of the multiple microcavity isolation regions arranged continuously along a set direction changes in a step-like manner.

7. A silicon-based OLED display device, characterized in that, It includes a driving circuit substrate, an anode metal layer, and a silicon-based OLED microdisplay strong microcavity anode structure as described in any one of claims 1 to 6, wherein the pixel definition layer is disposed on the anode metal layer.

8. The method for fabricating the strong microcavity anode structure of a silicon-based OLED microdisplay as described in any one of claims 1 to 6, characterized in that, Including the following steps: S1. Provide a driving circuit substrate; S2. An anode metal layer is formed on one side of the driving circuit substrate; S3. A microcavity structure layer is formed on the side of the anode metal layer away from the driving circuit substrate; S4. A pixel definition layer is formed on the side of the microcavity structure layer away from the driving circuit substrate; Pixel opening areas and pixel isolation areas are formed on the pixel definition layer.

9. The method for fabricating the strong microcavity anode structure of a silicon-based OLED microdisplay according to claim 8, characterized in that, The pixel isolation region is a stacked structure formed by SiO layer, SiN layer and SiO layer, with the SiN layer located between two SiO layers.

Images