Preparation method of Micro OLED anode structure capable of improving side luminous intensity

Abstract

The invention relates to manufacturing of a Micro OLED (Organic Light Emitting Diode), in particular to a preparation method of a Micro OLED anode structure for improving side luminous intensity, which comprises the following steps of: sequentially preparing a first SiO2 film layer and a SiN film layer on a substrate, and spin-coating a first photoresist layer on the surface of the SiN film layer; preparing a reflection bowl structure based on different etching rates of the first SiO2 film layer and the SiN film layer; preparing a metal film layer on the surface of the reflection bowl structure, spin-coating a second photoresist layer on the surface of the metal film layer, and only reserving the metal film layer in the reflection bowl; second SiO2 film layers with different thicknesses are prepared on the surfaces of the metal film layer in the reflection bowl and the SiN film layers on the two sides, ITO film layers are prepared on the surfaces of the second SiO2 film layers, and reflection bowl type Micro OLED anode structures with different gradients are obtained; according to the technical scheme provided by the invention, the defect of relatively low display brightness of an OLED (Organic Light Emitting Diode) product can be overcome.

Description

Technical Field

[0001] This invention relates to the manufacture of Micro OLEDs, and more specifically to a method for preparing a Micro OLED anode structure to improve lateral luminescence intensity. Background Technology

[0002] Micro OLED is a micro-display technology based on OLED but with smaller pixel sizes and higher resolution. It is mainly used in near-eye display devices (such as AR / VR headsets, electronic viewfinders, military helmets, etc.). The core features of Micro OLED are self-emissive, with each pixel emitting light independently, eliminating the need for backlighting. It also features high contrast, fast response speed, suitability for miniaturized devices, pixel density of over 5000 PPI, and low power consumption, consuming energy only when displaying content, with almost zero power consumption in black scenes.

[0003] One of the main reasons for the low brightness of OLED displays is that the light emitted from the emissive layer is scattered outwards, leading to a decrease in light intensity. Therefore, when faced with the problem of low light intensity caused by the dispersion of emitted light and its inability to be focused, how to create a novel anode structure to solve the problem of light dispersion and improve light intensity has become an urgent technical problem to be solved in this field. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides a method for preparing a Micro OLED anode structure to improve the side emission intensity, which can effectively overcome the defect of low display brightness of OLED products in the prior art.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A method for fabricating a Micro OLED anode structure to improve side-emitting intensity includes the following steps:

[0009] S1. A first SiO2 film layer and a SiN film layer are sequentially prepared on a substrate, and a first photoresist layer is spin-coated on the surface of the SiN film layer.

[0010] S2. Based on the different etching rates of the first SiO2 film layer and the SiN film layer, a reflective bowl structure is prepared.

[0011] S3. Prepare a metal film layer on the surface of the reflective bowl structure, spin-coat a second photoresist layer on the surface of the metal film layer, and retain only the metal film layer inside the reflective bowl to obtain a reflective bowl structure coated with a reflective layer.

[0012] S4. Prepare second SiO2 film layers of different thicknesses on the surface of the metal film layer inside the reflective bowl and the SiN film layer on both sides. Spin-coat the surface of the second SiO2 film layer with a third photoresist layer and retain only the second SiO2 film layer inside the reflective bowl to obtain a reflective bowl structure with parabolic surfaces of different angles.

[0013] S5. Prepare ITO film layers of different thicknesses on the surface of the second SiO2 film layer inside the reflective bowl and the SiN film layers on both sides. Spin-coat the surface of the ITO film layer with a fourth photoresist layer and retain only the ITO film layer inside the reflective bowl to obtain a reflective bowl-shaped Micro OLED anode structure with different slopes.

[0014] Preferably, in step S1, a first SiO2 film layer and a SiN film layer are sequentially prepared on the substrate, and a first photoresist layer is spin-coated onto the surface of the SiN film layer, comprising:

[0015] A first SiO2 film and a SiN film were sequentially prepared on a substrate using CVD process, and a first photoresist layer was spin-coated onto the surface of the SiN film.

[0016] The thickness of the first SiO2 film and the SiN film is 0.5~2μm.

[0017] Preferably, in S2, a reflective bowl structure is fabricated based on the different etching rates of the first SiO2 film layer and the SiN film layer, including:

[0018] S21. The intermediate first photoresist layer is removed using a photolithography development process;

[0019] S22. Using a dry etching process, while removing the first photoresist layers on both sides, the first SiO2 film and the SiN film begin to be etched downwards. Based on the different etching rates of the first SiO2 film and the SiN film, a reflective bowl structure is formed.

[0020] Preferably, in S22, a dry etching process is used to remove the first photoresist layers on both sides while the first SiO2 film and SiN film begin to be etched downwards. Based on the different etching rates of the first SiO2 film and SiN film, a reflective bowl structure is formed, including:

[0021] Since the etching rate of the SiN film is greater than that of the first SiO2 film, the etching length of the SiN film is greater than that of the first SiO2 film during the etching process. Furthermore, the isotropic etching of the dry etching process does not have directional selectivity. During the downward etching process, the etched portion above is gradually etched laterally. By controlling the lateral etching rate, a curved reflective bowl structure is gradually formed.

[0022] Preferably, in step S3, a metal film layer is prepared on the surface of the reflective bowl structure, a second photoresist layer is spin-coated on the surface of the metal film layer, and only the metal film layer inside the reflective bowl is retained, resulting in a reflective bowl structure coated with a reflective layer, comprising:

[0023] S31. A metal film layer is prepared on the surface of the reflective bowl structure using vapor deposition or PVD process, and a second photoresist layer is spin-coated on the surface of the metal film layer.

[0024] S32. The second photoresist layer on both sides is removed by photolithography development process;

[0025] S33. The second photoresist layer in the middle and the metal film layers on both sides are removed by etching process, leaving only the metal film layer inside the reflective bowl, to obtain a reflective bowl structure with a reflective layer.

[0026] The metal film is either an Al film or an Ag film, with the Al film having a thickness of 20-200 μm and the Ag film having a thickness of 10-200 μm.

[0027] Preferably, in step S4, second SiO2 films of different thicknesses are prepared on the surfaces of the metal film layer inside the reflective bowl and the SiN film layers on both sides. A third photoresist layer is spin-coated onto the surface of the second SiO2 film layer, and only the second SiO2 film layer inside the reflective bowl is retained, resulting in a reflective bowl structure with parabolic surfaces having different angles, including:

[0028] S41. Second SiO2 film layers of different thicknesses are prepared on the surface of the metal film layer inside the reflective bowl and the SiN film layer on both sides using vapor deposition or CVD process, and a third photoresist layer is spin-coated on the surface of the second SiO2 film layer.

[0029] S42. The third photoresist layer on both sides is removed by photolithography development process;

[0030] S43. The third photoresist layer in the middle and the second SiO2 film layers on both sides are removed by etching process, leaving only the second SiO2 film layer inside the reflective bowl, to obtain a reflective bowl structure with parabolic surfaces with different angles to cover different side emission angles.

[0031] Preferably, in step S5, ITO films of different thicknesses are prepared on the surfaces of the second SiO2 film layer inside the reflective bowl and the SiN film layers on both sides. A fourth photoresist layer is spin-coated onto the surface of the ITO film layer, and only the ITO film layer inside the reflective bowl is retained, resulting in a reflective bowl-shaped Micro OLED anode structure with different slopes, including:

[0032] S51. ITO film is deposited on the surface of the second SiO2 film layer inside the reflective bowl and the SiN film layer on both sides in one step to form ITO film layers of different thicknesses, and a fourth photoresist layer is spin-coated on the surface of the ITO film layer.

[0033] S52. The fourth photoresist layer on both sides is removed by photolithography development process;

[0034] S53. The fourth photoresist layer in the middle and the ITO film layers on both sides are removed by etching process, leaving only the ITO film layer inside the reflective bowl, to obtain a reflective bowl-shaped Micro OLED anode structure with different slopes.

[0035] The thickness of the ITO film is 10~200nm.

[0036] (III) Beneficial Effects

[0037] Compared with the prior art, the method for preparing a Micro OLED anode structure to improve side emission intensity provided by the present invention, based on the reflective bowl structure, constructs a reflective bowl structure with parabolic surfaces of different angles by matching the thickness of the second SiO2 film layer and the ITO film layer inside the reflective bowl. This design can not only minimize the loss of light during the reflection process, thereby improving the light emission intensity, but also enable OLED products to effectively cover different side emission angles. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0039] Figure 1 This is a schematic diagram of the process of the present invention;

[0040] Figure 2 This is a schematic diagram of the sequential fabrication of a first SiO2 film layer and a SiN film layer on a substrate in this invention, and the spin coating of a first photoresist layer on the surface of the SiN film layer.

[0041] Figure 3 This is a schematic diagram of the reflective bowl structure in this invention;

[0042] Figure 4 This is a schematic diagram of the reflective bowl structure coated with a reflective layer in this invention;

[0043] Figure 5 This is a schematic diagram of a reflective bowl structure with a parabolic surface having an angle in the present invention;

[0044] Figure 6 In this invention Figure 5Based on this, a schematic diagram of a sloped, reflective bowl-shaped Micro OLED anode structure is obtained;

[0045] Figure 7 In this invention Figure 6 Based on this, a schematic diagram of a Micro OLED anode structure was obtained;

[0046] Figure 8 This is a schematic diagram of another reflective bowl structure with a parabolic surface having an angle in this invention;

[0047] Figure 9 In this invention Figure 8 Based on this, a schematic diagram of a sloped, reflective bowl-shaped Micro OLED anode structure is obtained;

[0048] Figure 10 In this invention Figure 9 Based on this, a schematic diagram of another Micro OLED anode structure was obtained. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0050] The following describes the specific process of the Micro OLED anode structure fabrication method for improving side-emitting intensity provided by the present invention, using specific examples (e.g.) Figure 1 (as shown) and technical effects.

[0051] 1. A first SiO2 film layer and a SiN film layer are sequentially prepared on a substrate, and a first photoresist layer is spin-coated on the surface of the SiN film layer.

[0052] like Figure 2 As shown, a first SiO2 film layer and a SiN film layer are sequentially prepared on a substrate using CVD process, and a first photoresist layer is spin-coated on the surface of the SiN film layer.

[0053] The thickness of the first SiO2 film and the SiN film is 0.5~2μm.

[0054] II. Based on the different etching rates of the first SiO2 film layer and the SiN film layer, a reflective bowl structure is prepared.

[0055] 1) The first photoresist layer in the middle is removed using a photolithography development process;

[0056] 2) Using a dry etching process, while removing the first photoresist layers on both sides, the first SiO2 film and SiN film begin to be etched downwards. Based on the different etching rates of the first SiO2 film and SiN film, a reflective bowl structure is formed (e.g., Figure 3 (as shown), including:

[0057] Since the etching rate of the SiN film is greater than that of the first SiO2 film, the etching length of the SiN film is greater than that of the first SiO2 film during the etching process. Furthermore, the isotropic etching of the dry etching process does not have directional selectivity. During the downward etching process, the etched portion above is gradually etched laterally. By controlling the lateral etching rate, a curved reflective bowl structure is gradually formed.

[0058] 3. Prepare a metal film layer on the surface of the reflective bowl structure, spin-coat a second photoresist layer on the surface of the metal film layer, and retain only the metal film layer inside the reflective bowl to obtain a reflective bowl structure coated with a reflective layer.

[0059] 1) A metal film layer is prepared on the surface of the reflective bowl structure using vapor deposition or PVD process, and a second photoresist layer is spin-coated on the surface of the metal film layer;

[0060] 2) The second photoresist layers on both sides are removed using a photolithography development process;

[0061] 3) An etching process is used to remove the middle second photoresist layer and the metal film layers on both sides, leaving only the metal film layer inside the reflective bowl, resulting in a reflective bowl structure coated with a reflective layer (e.g., Figure 4 (as shown)

[0062] The metal film is either an Al film or an Ag film, with the Al film having a thickness of 20-200 μm and the Ag film having a thickness of 10-200 μm.

[0063] Fourth, prepare second SiO2 films of different thicknesses on the surface of the metal film layer inside the reflective bowl and the SiN film layer on both sides, spin-coat a third photoresist layer on the surface of the second SiO2 film layer, and retain only the second SiO2 film layer inside the reflective bowl to obtain a reflective bowl structure with parabolic surfaces of different angles.

[0064] 1) Second SiO2 films of different thicknesses are prepared on the surfaces of the metal film layer inside the reflector bowl and the SiN film layer on both sides using vapor deposition or CVD processes. Figure 5 In the structure shown, the thickness of the second SiO2 film is greater than Figure 8 (as shown in the diagram), and a third photoresist layer is spin-coated onto the surface of the second SiO2 film;

[0065] 2) The third photoresist layer on both sides is removed using a photolithography development process;

[0066] 3) An etching process is used to remove the middle third photoresist layer and the second SiO2 film layers on both sides, leaving only the second SiO2 film layer inside the reflective bowl, resulting in a reflective bowl structure with parabolic surfaces of different angles (e.g., Figure 5 and Figure 8 (as shown), to cover different side-emitting angles.

[0067] 5. ITO film layers of different thicknesses are prepared on the surface of the second SiO2 film layer inside the reflective bowl and the SiN film layers on both sides. A fourth photoresist layer is spin-coated on the surface of the ITO film layer, and only the ITO film layer inside the reflective bowl is retained, thus obtaining a reflective bowl-shaped Micro OLED anode structure with different slopes.

[0068] 1) ITO film is deposited on the surface of the second SiO2 film layer inside the reflective bowl and the SiN film layer on both sides in one step to form ITO film layers of different thicknesses, and a fourth photoresist layer is spin-coated on the surface of the ITO film layer.

[0069] 2) The fourth photoresist layer on both sides is removed using a photolithography development process;

[0070] 3) An etching process is used to remove the middle fourth photoresist layer and the ITO film layers on both sides, leaving only the ITO film layer inside the reflective bowl, resulting in a reflective bowl-shaped Micro OLED anode structure with different slopes (e.g., Figure 6 and Figure 7 ,as well as Figure 9 and Figure 10 (as shown)

[0071] The thickness of the ITO film is 10~200nm.

[0072] In the technical solution of this application, based on the reflective bowl structure, a reflective bowl structure with parabolic surfaces of different angles is constructed by matching the thickness of the second SiO2 film layer and the ITO film layer inside the reflective bowl. This design can not only minimize the loss of light during the reflection process, thereby improving the light emission intensity, but also enable OLED products to effectively cover different side emission angles.

[0073] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for fabricating a Micro OLED anode structure with improved lateral emission intensity, characterized in that: Includes the following steps: S1. A first SiO2 film layer and a SiN film layer are sequentially prepared on a substrate, and a first photoresist layer is spin-coated on the surface of the SiN film layer. S2. Based on the different etching rates of the first SiO2 film layer and the SiN film layer, a reflective bowl structure is prepared. S3. Prepare a metal film layer on the surface of the reflective bowl structure, spin-coat a second photoresist layer on the surface of the metal film layer, and retain only the metal film layer inside the reflective bowl to obtain a reflective bowl structure coated with a reflective layer. S4. Prepare second SiO2 film layers of different thicknesses on the surface of the metal film layer inside the reflective bowl and the SiN film layer on both sides. Spin-coat the surface of the second SiO2 film layer with a third photoresist layer and retain only the second SiO2 film layer inside the reflective bowl to obtain a reflective bowl structure with parabolic surfaces of different angles. S5. Prepare ITO film layers of different thicknesses on the surface of the second SiO2 film layer inside the reflective bowl and the SiN film layers on both sides. Spin-coat the surface of the ITO film layer with a fourth photoresist layer and retain only the ITO film layer inside the reflective bowl to obtain a reflective bowl-shaped Micro OLED anode structure with different slopes.

2. The method for fabricating a Micro OLED anode structure with improved lateral emission intensity according to claim 1, characterized in that: In S1, a first SiO2 film layer and a SiN film layer are sequentially prepared on a substrate, and a first photoresist layer is spin-coated onto the surface of the SiN film layer, including: A first SiO2 film and a SiN film were sequentially prepared on a substrate using CVD process, and a first photoresist layer was spin-coated onto the surface of the SiN film. The thickness of the first SiO2 film and the SiN film is 0.5~2μm.

3. The method for fabricating a Micro OLED anode structure with improved lateral emission intensity according to claim 1, characterized in that: Based on the different etching rates of the first SiO2 film and the SiN film in S2, a reflective bowl structure is fabricated, including: S21. The intermediate first photoresist layer is removed using a photolithography development process; S22. Using a dry etching process, while removing the first photoresist layers on both sides, the first SiO2 film and the SiN film begin to be etched downwards. Based on the different etching rates of the first SiO2 film and the SiN film, a reflective bowl structure is formed.

4. The method for fabricating a Micro OLED anode structure with improved lateral emission intensity according to claim 3, characterized in that: In S22, a dry etching process is used to remove the first photoresist layers on both sides while the first SiO2 film and SiN film begin to be etched downwards. Based on the different etching rates of the first SiO2 film and SiN film, a reflective bowl structure is formed, including: Since the etching rate of the SiN film is greater than that of the first SiO2 film, the etching length of the SiN film is greater than that of the first SiO2 film during the etching process. Furthermore, the isotropic etching of the dry etching process does not have directional selectivity. During the downward etching process, the etched portion above is gradually etched laterally. By controlling the lateral etching rate, a curved reflective bowl structure is gradually formed.

5. The method for fabricating a Micro OLED anode structure with improved lateral emission intensity according to claim 1, characterized in that: In step S3, a metal film layer is prepared on the surface of the reflective bowl structure. A second photoresist layer is spin-coated onto the surface of the metal film layer, and only the metal film layer inside the reflective bowl is retained, resulting in a reflective bowl structure coated with a reflective layer, including: S31. A metal film layer is prepared on the surface of the reflective bowl structure using vapor deposition or PVD process, and a second photoresist layer is spin-coated on the surface of the metal film layer. S32. The second photoresist layer on both sides is removed by photolithography development process; S33. The second photoresist layer in the middle and the metal film layers on both sides are removed by etching process, leaving only the metal film layer inside the reflective bowl, to obtain a reflective bowl structure with a reflective layer. The metal film is either an Al film or an Ag film, with the Al film having a thickness of 20-200 μm and the Ag film having a thickness of 10-200 μm.

6. The method for fabricating a Micro OLED anode structure with improved lateral emission intensity according to claim 1, characterized in that: In S4, second SiO2 films of different thicknesses are prepared on the surfaces of the metal film layer inside the reflective bowl and the SiN film layers on both sides. A third photoresist layer is spin-coated on the surface of the second SiO2 film layer, and only the second SiO2 film layer inside the reflective bowl is retained, resulting in a reflective bowl structure with parabolic surfaces of different angles, including: S41. Second SiO2 film layers of different thicknesses are prepared on the surface of the metal film layer inside the reflective bowl and the SiN film layer on both sides using vapor deposition or CVD process, and a third photoresist layer is spin-coated on the surface of the second SiO2 film layer. S42. The third photoresist layer on both sides is removed by photolithography development process; S43. The third photoresist layer in the middle and the second SiO2 film layers on both sides are removed by etching process, leaving only the second SiO2 film layer inside the reflective bowl, to obtain a reflective bowl structure with parabolic surfaces with different angles to cover different side emission angles.

7. The method for fabricating a Micro OLED anode structure with improved lateral emission intensity according to claim 1, characterized in that: In S5, ITO films of different thicknesses are prepared on the surfaces of the second SiO2 film layer inside the reflective bowl and the SiN films on both sides. A fourth photoresist layer is spin-coated onto the surface of the ITO film layer, and only the ITO film layer inside the reflective bowl is retained, resulting in a reflective bowl-shaped Micro OLED anode structure with different slopes, including: S51. ITO film is deposited on the surface of the second SiO2 film layer inside the reflective bowl and the SiN film layer on both sides in one step to form ITO film layers of different thicknesses, and a fourth photoresist layer is spin-coated on the surface of the ITO film layer. S52. The fourth photoresist layer on both sides is removed by photolithography development process; S53. The fourth photoresist layer in the middle and the ITO film layers on both sides are removed by etching process, leaving only the ITO film layer inside the reflective bowl, to obtain a reflective bowl-shaped Micro OLED anode structure with different slopes. The thickness of the ITO film is 10~200nm.

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