Silicon-based OLED device structure

Abstract

The invention discloses a silicon-based OLED (Organic Light Emitting Diode) device structure, which comprises a reflection anode layer, an organic common layer and a cathode layer, a group of anode ITO (Indium Tin Oxide) is arranged between the reflection anode layer and the organic common layer, the cathode layer is arranged on the organic common layer, and the group of anode ITO is ITO film layers with different refractive indexes and the same thickness. Red, green and blue (RGB) three-color pixel anodes corresponding to different refractive indexes are realized by adjusting process parameters and doping composite materials, micro-cavity adjustment of an RGB device is realized on the premise of ensuring the same thickness of ITO, a common cathode can be ensured to have no height segment difference, and the failure risk caused by cathode breakage is reduced; an independent optical modulation layer does not need to be arranged, and the overall thickness of the display device can be prevented from being increased.

Description

Technical Field

[0001] The present invention relates to the technical field of display devices, and in particular to a silicon-based OLED device structure. Background Art

[0002] Silicon-based OLED near-eye display products require a higher pixel density (>3000ppi). The traditional FMM (precision mask) evaporation method is difficult to cope with this pixel density. Therefore, the mainstream silicon-based OLED structure is WOLED+CF (color film). The OLED film layer is a common layer. The device microcavity is adjusted by adjusting the thickness of the RGB anode ITO to achieve monochromatic light. However, the thickness of the common layer cathode (usually Mg:Ag) is about 15nm, which will cause the risk of cathode breakage due to the 50nm height difference of the anode ITO (such as Figure 2 As shown), the cathode is not conducting laterally and this manifests itself as dark spots / poor lines on the screen.

[0003] Therefore, in order to improve the above problems, it is possible to consider reducing the height difference between the ITOs or using the same ITO thickness to prepare the RGB pixel anodes respectively, so that the cathode can be deposited on a flat surface and the related defects can be improved; for example, patent CN106449700A discloses a top-emitting WOLED display, in which an optical modulation layer of uniform thickness is added between the anode layer and the reflective metal layer of the three RGB sub-pixels of the display. By setting the optical modulation layer, the distance from the WOLED layer to the reflective metal layer can be increased, the total cavity length of the white light OLED is increased, and the top-emitting WOLED microcavity effect is overcome. In this way, there is no need to increase the anode thickness of the three blue, green and red sub-pixels in sequence, and only the anode layers of R, G and B need to be set to have the same thickness, respectively, so as to achieve white light with three peaks of red, green and blue; an optical modulation layer is added between the anode layer and the reflective metal layer, which increases the overall thickness of the display device structure. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a silicon-based OLED device structure, which can achieve the same thickness as ITO without increasing the overall thickness of the device, thereby reducing the risk of cathode breakage.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] The silicon-based OLED device structure includes a reflective anode layer, an organic common layer and a cathode layer. A group of anode ITO is arranged between the reflective anode layer and the organic common layer. The cathode layer is arranged on the organic common layer. The group of anode ITO is an ITO film layer with different refractive indices and the same thickness.

[0007] Further or preferred:

[0008] The ITO film layer can achieve the same thickness control with different refractive indexes by adjusting the Ar:O2 ratio or sputtering power in the anode ITO film forming process.

[0009] The ITO film layer can achieve the same thickness control with different refractive indexes by doping elements.

[0010] In the film forming process of the ITO film layer, the ratio of Ar:O2 is changed with a fixed power; the Ar flow rate is fixed and the O2 flow rate is changed, and the O2 flow rate range is 5-30 sccm. The refractive index range is 1.7-2.1.

[0011] In the film forming process of the ITO film layer, the ratio of Ar:O2 is fixed at 5:1, and the sputtering power is changed, and the sputtering power range is 80-160 W. The refractive index range is 1.8-2.2.

[0012] In the film forming process of the ITO film layer, the metal elements tin or zinc or titanium or aluminum are doped, and the non-metallic elements fluorine or nitrogen are doped.

[0013] In the film forming process of the ITO film layer, a high refractive index material and a low refractive index material are compounded.

[0014] The refractive index range of the ITO film layer is controlled within a range of 1.7-2.4.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] The silicon-based OLED device has a reasonable structural design. By adjusting process parameters and composite material doping, different refractive indices can be achieved corresponding to the red, green and blue (RGB) three-color pixel anodes. The microcavity adjustment of the RGB device is achieved under the premise of ensuring the same ITO thickness, which can ensure that the common cathode has no height step difference and reduce the risk of failure caused by cathode breakage. There is no need to set up a separate optical modulation layer, which can avoid increasing the overall thickness of the display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following is a brief description of the contents and symbols in the drawings of this specification:

[0018] Figure 1 This is a schematic diagram of the structure of the silicon-based OLED device of the present invention.

[0019] Figure 2 Schematic diagram of the structure of existing silicon-based OLED devices.

[0020] In the figure:

[0021] 1. Anode layer, 2. Organic common layer, 3. Cathode layer. DETAILED DESCRIPTION

[0022] The specific implementation modes of the present invention will be further explained in detail below through the description of embodiments with reference to the accompanying drawings.

[0023] like Figure 1 As shown, the silicon-based OLED device structure includes a reflective anode layer 1, an organic common layer 2 and a cathode layer 3. A group of anode ITO is arranged between the reflective anode layer 1 and the organic common layer 2, and the group of anode ITO is B-ITO, G-ITO and R-ITO respectively; the cathode layer is arranged on the organic common layer, and the group of anode ITO is an ITO film layer with different refractive indices and the same thickness; it mainly realizes red, green and blue (RGB) three-color pixel anodes corresponding to different refractive indices by adjusting the ITO film forming process parameters and the doping of composite materials, and realizes the microcavity adjustment of the RGB device under the premise of ensuring the same thickness of ITO, which can ensure that the common cathode has no height step difference, and reduce the failure risk caused by cathode breakage.

[0024] Specifically, the ITO film layer can achieve the same thickness control of different refractive indices by adjusting the Ar:O2 ratio or sputtering power in the anode ITO film forming process. The ITO film layer can achieve the same thickness control of different refractive indices by doping elements. In addition, in the film forming process of the ITO film layer, high refractive index materials and low refractive index materials are compounded.

[0025] In the film forming process of the ITO film layer, the Ar:O2 ratio is changed with a fixed power; the Ar flow rate is fixed and the O2 flow rate is changed, and the O2 flow rate range is 5-30sccm; the refractive index range is 1.7-2.1.

[0026] Alternatively, in the film forming process of the ITO film layer, the Ar:O2 ratio is fixed at 5:1, the sputtering power is changed, and the sputtering power range is 80-160W; the refractive index range is 1.8-2.2.

[0027] And in the film forming process of the ITO film layer, the metal elements tin or zinc or titanium or aluminum are doped, and the non-metallic elements fluorine or nitrogen are doped.

[0028] The silicon-based OLED device of the present invention has a reasonable structural design. Different refractive indices are achieved mainly by adjusting the anode ITO film-forming process parameters or introducing metal element doping. The RGB device microcavity can be adjusted under the premise of the same ITO thickness. WOLED uses a Single device without a CGL (charge generation layer), which reduces the lateral crosstalk of the OLED organic common layer and improves the power consumption of the product. The cathode Mg:Ag can be film-formed on a flat surface, reducing the risk of breakage due to height difference, so the Mg:Ag thickness can be reduced (B device requires a thinner cathode to achieve high efficiency compared to GR).

[0029] Preferred embodiments of the present invention are:

[0030] like Figure 1As shown, this embodiment provides a silicon-based OLED device structure, in which a transparent conductive electrode ITO layer is prepared above the reflective anode layer, and different refractive indices corresponding to red, green and blue (RGB) three-color pixel anodes are achieved by adjusting process parameters and composite material doping, so that microcavity adjustment of the RGB device is achieved under the premise of the same ITO thickness, which can ensure that the common cathode has no height step difference, reducing the risk of failure due to cathode breakage.

[0031] This example is based on a single device structure. The absence of a CGL layer can reduce the risk of lateral electrical crosstalk caused by metal doping. The ITO thicknesses corresponding to the current single BGR device are 700A, 1100A, and 1600A, respectively. The target emission peak values ​​are 460nm, 530nm, and 610nm. The microcavity is adjusted to a second-order microcavity, and the ITO refractive index is about 1.75. According to the microcavity formula of the top-emitting OLED device, According to calculation, the RGB ITO thickness can be selected as 2333A, and the corresponding refractive indices required for BGR devices are 1.7, 2.0, and 2.34, respectively. Therefore, if the different ITO refractive indices are adjusted, the same ITO thickness of 2333A can be guaranteed for the RGB devices, while ensuring the original microcavity adjustment and thickness. After the ITO sputtering film is completed, the OLED organic film layer and cathode are deposited by vacuum evaporation. Each film layer uses a common mask (CMM) to prepare a TFE encapsulation layer on top of the OLED film layer. Since the thickness of the ITO and OLED organic film layers of the three RGB colors is consistent, there is no risk of height step difference and cathode breakage.

[0032] The refractive index of ITO can be adjusted by changing the coating process parameters: ① adjusting the Ar:O2 ratio; ② changing the power; the refractive index of ITO can be adjusted by introducing doping elements: ① metal element doping (tin, zinc, titanium, aluminum); ② non-metallic doping (fluorine, nitrogen); the refractive index of ITO can be compounded with other materials: ① with high refractive index materials (titanium dioxide, zirconium dioxide, etc.); ② compounded with low refractive index materials (magnesium fluoride, silicon dioxide, etc.); the refractive index range of ITO is 1.7-2.4.

[0033] 1. The refractive index of ITO can be adjusted by changing the coating process parameters: ① adjusting the ratio of Ar:O2; ② changing the power;

[0034] The Ar:O2 ratio was changed with fixed power, sputtering power was 100W, bottom temperature was 200℃, process time was 1h, Ar was fixed at 50sccm, and O2 flow rate was changed;

[0035] 0. Flow rate (sccm) Ar flow rate (sccm) Ar::(0 vs. Refractive index ne 5 50- 10:1 2.045 10 50。 5:1l。 1.985 20。 50。 5:22。 1.878。 30。 50 5:3 1.705-

[0036] The Ar:O2 ratio was fixed at 5:1, the bottom temperature was 200°C, the process time was 1h, the Ar was fixed at 50sccm, and the O2 sputtering power was changed;

[0037] Ar:0. Sputtering power(W) Refractive index n 5:11。 80。 1.895 5:11。 100 1.985 5:11。 120。 2.054。 5:11 140 2.105 5:11 160 2.085

[0038] 2. The refractive index of ITO can be increased by introducing doping elements: ① metal doping (tin, zinc, titanium, aluminum); ② non-metal doping (fluorine, nitrogen);

[0039] Doping with zinc:

[0040] Zn doping ratio (%) Refractive index ne 0 2.054 2。 2.038。 4 2.015

[0041] Doped with aluminum:

[0042] Al doping ratio (%) Refractive index n 0 2.054 2。 2.065 4 2.105-

[0043] 3. ITO refractive index adjustment can be compounded with other materials: ① with high refractive index materials (titanium dioxide, zirconium dioxide); ② with low refractive index materials (magnesium fluoride, silicon dioxide);

[0044] TiO, doping ratio (%) Refractive index n@550nm- 0- 2.054 2。 2.185- 4 2.225 6 2.338

[0045] Since silicon-based OLED adopts WOLED+CF mode, the common layer of organic materials needs to balance the performance of three-color devices. Usually, traditional fluorescent materials are used for blue light, which has relatively low efficiency. In order to ensure the efficiency of white light devices, the performance of blue light devices needs to be improved as much as possible. Since the transmittance of cathode materials is low in short waves (blue light region), blue light devices usually require a thinner cathode thickness than red and green. This solution can ensure that the risk of cathode breakage is reduced under the premise of thinner cathode thickness, and reduce the preparation of the second auxiliary cathode (commonly used IZO).

[0046] The present invention realizes red, green and blue (RGB) three-color pixel anodes corresponding to different refractive indices by adjusting process parameters and composite material doping, and realizes microcavity adjustment of RGB devices under the premise of ensuring the same thickness of ITO, which can ensure that the common cathode has no height step difference and reduce the failure risk caused by cathode breakage; there is no need to set a separate optical modulation layer, which can avoid increasing the overall thickness of the display device.

[0047] The above is only an explanation of the preferred embodiments of the present invention, and the above technical features can be arbitrarily combined to form multiple embodiments of the present invention.

[0048] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A silicon-based OLED device structure, comprising a reflective anode layer, an organic common layer and a cathode layer, wherein a group of anode ITO is arranged between the reflective anode layer and the organic common layer, and the cathode layer is arranged on the organic common layer, characterized in that: The group of anode ITOs are ITO film layers with different refractive indices and the same thickness.

2. The silicon-based OLED device structure according to claim 1, characterized in that: The ITO film layer can achieve the same thickness control with different refractive indexes by adjusting the Ar:O2 ratio or sputtering power in the anode ITO film forming process.

3. The silicon-based OLED device structure according to claim 1, characterized in that: The ITO film layer can achieve the same thickness control with different refractive indexes by doping elements.

4. The silicon-based OLED device structure as claimed in claim 2, characterized in that: In the film forming process of the ITO film layer, the Ar:O2 ratio is changed with a fixed power; the Ar flow rate is fixed and the O2 flow rate is changed, and the O2 flow rate range is 5-30sccm.

5. The silicon-based OLED device structure as claimed in claim 2, characterized in that: In the film forming process of the ITO film layer, the Ar:O2 ratio is fixed at 5:1, and the sputtering power is changed, and the sputtering power range is 80-160W.

6. The silicon-based OLED device structure as claimed in claim 4, characterized in that: The refractive index ranges from 1.7 to 2.

1.

7. The silicon-based OLED device structure as claimed in claim 5, characterized in that: The refractive index ranges from 1.8 to 2.

2.

8. The silicon-based OLED device structure as claimed in claim 2, characterized in that: In the film forming process of the ITO film layer, the metal elements tin or zinc or titanium or aluminum are doped, and the non-metallic elements fluorine or nitrogen are doped.

9. The silicon-based OLED device structure as claimed in claim 8, characterized in that: In the film forming process of the ITO film layer, a high refractive index material and a low refractive index material are compounded.

10. The silicon-based OLED device structure according to any one of claims 1 to 9, characterized in that: The refractive index range of the ITO film layer is controlled within a range of 1.7-2.4.

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