OLED display panel, preparation method and display device

Abstract

The invention discloses an OLED display panel, a preparation method and a display device.The OLED display panel is of a multi-layer structure and sequentially comprises a substrate, a circuit layer, a passivation layer, a planarization layer, an organic light-emitting layer and a top electrode from bottom to top; the circuit layer comprises a TFT (Thin Film Transistor) region; the OLED display panel further comprises a mask layer, and the mask layer is clamped between the organic light-emitting layer and the circuit layer. The mask layer is located between the organic light-emitting layer and the circuit layer and is used for absorbing laser energy, so that the circuit layer can be ensured to be thoroughly cut through and the success rate of laser repair can be guaranteed when laser with relatively large energy is adopted to cut the circuit layer, and most laser energy can be absorbed by the mask layer when the laser penetrates through the circuit layer to reach the mask layer, so that the laser repair efficiency is improved. The energy of the laser penetrating through the mask layer is small, the remaining laser cannot break down the organic light-emitting layer and the top electrode, water and oxygen can be prevented from entering the organic light-emitting layer, and the service life of the OELD display panel is also prevented from being shortened.

Description

Technical Field

[0001] The present invention relates to the technical field of display panels, and in particular to an OLED display panel, a preparation method and a display device. Background Art

[0002] OLED (organic light-emitting diode) display devices have the characteristics of self-luminescence, wide viewing angle, high luminous efficiency, low power consumption, fast response time, simple manufacturing process and low cost, and are widely used.

[0003] Usually, when a pixel in an OLED display panel has a bright spot or a dark spot, it is necessary to perform dark spot laser repair, that is, cutting off part of the circuit in the TFT (Thin Film Transistor) area. However, during the repair, the laser energy is difficult to control. When the laser energy is small, the circuit cannot be effectively cut off, resulting in repair failure. When the laser energy is too large, the organic light-emitting layer and the top electrode may be broken down. At this time, water and oxygen can easily enter the organic light-emitting layer in the pixel. The accumulation of water and oxygen in the OLED display panel will inactivate the functional layer material of the OLED device. The organic light-emitting layers of different pixels are connected, which will eventually affect the life of the OLED display panel. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides an OLED display panel, a preparation method and a display device.

[0005] In a first aspect, the present invention provides an OLED display panel, wherein the OLED display panel is a multi-layer structure, and includes, from bottom to top, a substrate, a circuit layer, a passivation layer, a planarization layer, an organic light-emitting layer, and a top electrode; the circuit layer includes a TFT region;

[0006] The OLED display panel further comprises a mask layer, which is sandwiched between the organic light-emitting layer and the circuit layer, and is used for absorbing laser energy.

[0007] Optionally, the thickness of the mask layer is positively correlated with the thickness of the TFT region.

[0008] Optionally, the mask layer is located between the planarization layer and the passivation layer.

[0009] Optionally, the mask layer includes a shading film, which corresponds to the position of the TFT region in the vertical direction, and an area of ​​the shading film is less than or equal to an area of ​​the passivation layer and the planarization layer, and is greater than or equal to an area of ​​the TFT region.

[0010] Optionally, the color of the shading film is red.

[0011] Optionally, the OLED display panel further includes a bottom electrode, and the bottom electrode is arranged between the planar layer and the organic light-emitting layer.

[0012] In a second aspect, the present invention provides a method for preparing an OLED display panel, comprising the following steps:

[0013] Preparing a circuit layer on a substrate, wherein the circuit layer includes a TFT region;

[0014] Sequentially preparing a passivation layer and a planarization layer on the circuit layer;

[0015] Sequentially preparing an organic light-emitting layer and a top electrode on the planarization layer;

[0016] During the preparation process, a mask layer is arranged with the circuit layer, the passivation layer or the planarization layer as a base plate, so that the mask layer is sandwiched between the organic light-emitting layer and the circuit layer, and the mask layer is used to absorb laser energy.

[0017] Optionally, setting the mask layer includes the following steps:

[0018] Determine the base plate of the mask layer;

[0019] Using the area on the bottom plate vertically corresponding to the TFT area as a light shielding area;

[0020] A light-shielding film is provided in the light-shielding area to obtain a mask layer.

[0021] Optionally, the mask layer is located between the circuit layer and the planarization layer, and before the organic light-emitting layer and the top electrode are sequentially prepared on the planarization layer, the method further includes:

[0022] A bottom electrode is prepared on the planarization layer.

[0023] In a third aspect, the present invention provides a display device, characterized in that the display device comprises the OLED display panel according to any one of the first aspects of claim 1.

[0024] The OLED display panel provided by the embodiment of the present invention is a multi-layer structure, which includes a substrate, a circuit layer, a passivation layer, a planarization layer, an organic light-emitting layer and a top electrode from the bottom to the top; the circuit layer includes a TFT area; the OLED display panel also includes a mask layer, which is sandwiched between the organic light-emitting layer and the circuit layer. Since the mask layer is located between the organic light-emitting layer and the circuit layer, and the mask layer is used to absorb laser energy, when a laser with a large energy is used to cut the circuit layer, it can be ensured that the circuit layer is completely cut through, thereby ensuring the success rate of laser repair. Moreover, when the laser passes through the circuit layer to reach the mask layer, most of the laser energy can be absorbed by the mask layer, and the laser energy passing through the mask layer is small, so the remaining laser cannot penetrate the organic light-emitting layer and the top electrode, thereby preventing water and oxygen from entering the organic light-emitting layer and also preventing the life of the OLED display panel from being shortened.

[0025] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 is a schematic diagram of the structure of an OLED display panel provided by an embodiment of the present invention;

[0028] Figure 2 is a schematic diagram of a pixel circuit structure provided by an embodiment of the present invention;

[0029] Figure 3 This is an effect diagram of water and oxygen entering an organic light-emitting layer in a pixel provided by an embodiment of the present invention;

[0030] Figure 4 is a schematic diagram of another OLED display panel structure provided by an embodiment of the present invention;

[0031] Figure 5 is a structural schematic diagram of another OLED display panel provided by an embodiment of the present invention;

[0032] Figure 6 It is a schematic diagram of cutting positions in a pixel structure provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0034] In one embodiment of the present invention, Figure 1 The schematic diagram of the OLED display panel structure shown in the figure provides an OLED display panel. The OLED display panel is a multi-layer structure, which includes a substrate 10, a circuit layer 20, a passivation layer 30, a planarization layer 40, an organic light-emitting layer 50 and a top electrode 60 from the bottom to the top. The material of the substrate 10 can be rigid glass, and the material of the circuit layer 20 is usually a conductive metal, such as copper (Cu); the passivation layer 30 is used to prevent the circuit layer 20 from being injected or oxidized by water vapor, and its material is usually a stable oxide, such as SiO2; the planarization layer 40 is used to flatten the surface of the existing pixel structure, provide a base plate with a uniformly flat upper surface for preparing the structure of the upper layer, and can protect the lower layer. The organic light-emitting material in the organic light-emitting layer 50 can be divided into small molecules and polymers according to the type of organic matter. The main difference between the two devices is the manufacturing process. The small molecule device mainly adopts the vacuum thermal evaporation process, and the polymer device adopts the spin coating or spray printing process.

[0035] The circuit layer 20 includes a TFT region, which is a region where a thin film transistor (TFT) is disposed. Figure 2 A schematic diagram of a pixel circuit structure provided by an embodiment of the present invention is shown in FIG. Figure 2 As shown, each pixel in the display panel includes a TFT area and a light-emitting part D. The TFT area is a display driving circuit, which can control the light-emitting part D to emit light. The TFT area includes a power supply line EVdd, a current regulating transistor TR2, a signal control line Vdata and a voltage compensation line Vref. Among them, the current regulating transistor TR2 is a MOS tube, that is, a metal-oxide-semiconductor field-effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor), referred to as MOSFET, which is a common type of transistor. The source of the current regulating transistor TR2 is connected to the power supply line EVdd, the drain is connected to the light-emitting part D and the voltage compensation line Vref, and the gate is connected to the signal control line Vdata. Of course, the TFT area can also include a switch control transistor TR1, a current detection transistor TR3 and a resistor R, and TR1 and TR3 are both MOS tubes.

[0036] When a pixel has a bright spot or a dark spot defect, a laser is used to cut the circuit in the TFT area of ​​the defective pixel, that is, to cut off the control circuit of the light-emitting part to make the pixel dark.

[0037] In another optional embodiment, after cutting is completed, the light-emitting part of the defective pixel can be connected to a normally operating circuit part, that is, the control circuit is replaced to restore the light emission of the defective pixel to normal. The present invention does not limit the process after cutting and repair.

[0038] For Figure 1 When using laser to repair OLED display panels, if the laser energy is small, the circuit cannot be effectively cut off, resulting in repair failure. If the laser energy is too large, the organic light-emitting layer and the top electrode may be broken down. At this time, water and oxygen can easily enter the organic light-emitting layer in the pixel, resulting in the following specific effects: Figure 3 As shown, the accumulation of water and oxygen in the OLED display panel will inactivate the functional layer materials of the OLED device. The organic light-emitting areas of different pixels are connected. When the organic light-emitting area of ​​a pixel is corroded by water and oxygen, the organic light-emitting areas of other surrounding pixels will also be gradually corroded by water and oxygen over time, causing dark spots in the surrounding pixels, which will eventually affect the life of the OELD display panel.

[0039] Therefore, the OLED display panel in the present invention also includes a mask layer, which is sandwiched between the organic light-emitting layer and the circuit layer. The mask layer is used to absorb laser energy. The laser has less remaining energy after passing through the mask layer, and it is difficult to penetrate the organic light-emitting layer and the top electrode, which can effectively prevent the organic light-emitting layer from being exposed to the air and being corroded by water and oxygen.

[0040] Generally speaking, after adding a mask layer, in order to avoid the entire display panel being too thick, the thickness of the flat layer will be appropriately reduced. Assuming that the thickness of the flat layer is H1 when the mask layer is not added, and the thickness of the flat layer is H2 when the mask layer is added, and the thickness of the mask layer is H3, then H3+H2=H1 can be made, and the increase in the thickness of the display panel can be avoided. Of course, it is also feasible when the difference between H3+H2 and H1 is small, and the present invention is not limited to this.

[0041] Optionally, the material of the planarization layer is a hydrophobic organic material, preferably a polyimide material or polymethyl methacrylate. The hydrophobic organic material can also further prevent water vapor erosion.

[0042] In an optional example A, the OLED display panel includes, from bottom to top, a substrate, a circuit layer, a mask layer, a passivation layer, a mask layer, a planarization layer, an organic light-emitting layer and a top electrode. The laser can penetrate the substrate and the circuit layer, and the laser energy is greatly reduced after passing through the mask layer 70. The remaining energy is low, and it is difficult to penetrate other layers after the mask layer (including the organic light-emitting layer), thereby preventing water and oxygen from entering the organic light-emitting layer.

[0043] In another optional example B, the OLED display panel includes a substrate, a circuit layer, a passivation layer, a planarization layer, a mask layer, an organic light-emitting layer and a top electrode from bottom to top. The laser can penetrate the substrate and the circuit layer, and the laser energy is greatly reduced after passing through the mask layer 70. The remaining energy is low, and it is difficult to penetrate the organic light-emitting layer and the top electrode behind the mask layer, thereby preventing water and oxygen from entering the organic light-emitting layer.

[0044] In yet another alternative example C, Figure 4 Another schematic diagram of the structure of an OLED display panel is shown. Figure 4 As shown, the mask layer 70 is located between the planarization layer 40 and the passivation layer 30. The OLED display panel includes a substrate 10, a circuit layer 20, a passivation layer 30, a mask layer 70, a planarization layer 40, an organic light-emitting layer 50 and a top electrode 60 from the bottom to the top. The laser can penetrate the substrate 10, the circuit layer 20, and the passivation layer 30, and the laser energy is greatly reduced after passing through the mask layer 70, and the residual energy is low, and it is difficult to penetrate the planarization layer 40, the organic light-emitting layer 50 and the top electrode 60 after the mask layer 70, thereby preventing water and oxygen from entering the organic light-emitting layer 50. In addition, the advantage of the mask layer 70 being located between the planarization layer 40 and the passivation layer 30 is that, first, when preparing the display panel, etching, deposition and other processes are required. If the mask layer 70 is prepared earlier, the mask layer 70 needs to be protected when preparing other layers on the mask layer 70 to avoid damage to the mask layer 70 and affect its absorption effect on laser energy. In this example, the mask layer 70 is arranged between the planarization layer 40 and the passivation layer 30, so the preparation order of the mask layer 70 is later, and a large number of other layers have been prepared before the mask layer 70, which can reduce damage to the mask layer 70, thereby ensuring the effect of the mask layer 70 in absorbing laser energy.

[0045] The OLED display panel provided by the embodiment of the present invention is a multi-layer structure, which includes a substrate, a circuit layer, a passivation layer, a planarization layer, an organic light-emitting layer and a top electrode from the bottom to the top; the circuit layer includes a TFT area; the OLED display panel also includes a mask layer, which is sandwiched between the organic light-emitting layer and the circuit layer. Since the mask layer is located between the organic light-emitting layer and the circuit layer, and the mask layer is used to absorb laser energy, when a laser with a large energy is used to cut the circuit layer, it can be ensured that the circuit layer is completely cut through, thereby ensuring the success rate of laser repair. Moreover, when the laser passes through the circuit layer to reach the mask layer, most of the laser energy can be absorbed by the mask layer, and the laser energy passing through the mask layer is small, so the remaining laser cannot penetrate the organic light-emitting layer and the top electrode, thereby preventing water and oxygen from entering the organic light-emitting layer and also preventing the life of the OLED display panel from being shortened.

[0046] In an optional embodiment, the thickness of the mask layer is positively correlated with the thickness of the TFT region. As described above, the mask layer is used to absorb laser energy, and the laser is mainly used to cut the circuit in the TFT region. When the thickness of the TFT region is large, the required laser energy is high. At this time, a mask layer with a stronger ability to absorb laser energy is required. When the thickness of the mask layer increases, the ability of the mask layer to absorb laser energy becomes stronger. Therefore, setting the thickness of the mask layer to be positively correlated with the thickness of the TFT region can enable the mask layer to effectively absorb the energy of the laser and protect the organic light-emitting layer from being broken down.

[0047] Optionally, the mask layer includes a light shielding film, which is a colored polymer material. The light shielding film corresponds to the position of the TFT area in the vertical direction, and the area of ​​the light shielding film is less than or equal to the area of ​​the passivation layer and the planarization layer, and is greater than or equal to the area of ​​the TFT area. Laser cutting is usually performed in the vertical direction of the device (the laser is located on the substrate side of the device). The purpose of this setting is to ensure that the light shielding film can cover the laser cutting area, reduce the use area of ​​the light shielding film, and save the use cost of the light shielding film. In one case, the mask layer is composed only of the light shielding film. In another case, the mask layer includes the light shielding film and the ordinary film, that is, other areas in the mask layer except the light shielding film can be made of ordinary films, which can also reduce the cost of the mask layer.

[0048] Optionally, the color of the shading film is red. In addition, the color of the shading film can also be blue. Compared with the red shading film, the blue shading film has a weaker absorption capacity for the energy of the laser. The color of the shading film can be selected according to the intensity of the laser used, and the present invention is not limited to this.

[0049] Optionally, the mask layer may include only a shading film, the position of the shading film corresponds to the position of the TFT area, and the shading film is embedded in the planarization layer. Then, for the planarization layer, the shading film is only provided in the area corresponding to the TFT area, which can reduce the material usage of the planarization layer.

[0050] Optionally, the OLED display panel also includes a bottom electrode, which is a metal layer. Etching and other processes are usually used. If the bottom plate for preparing the bottom electrode is a mask layer, the mask layer is easily damaged, affecting the shading effect. Therefore, when it is necessary to prepare the bottom electrode, the planarization layer is used as the bottom plate of the bottom electrode, and the mask layer can only be located between the circuit layer and the planarization layer. Figure 5 A schematic diagram of the structure of another OLED display panel is shown. Figure 5 As shown, the bottom electrode 80 is arranged between the planar layer 40 and the organic light-emitting layer 50. The OLED display panel includes a substrate 10, a circuit layer 20, a passivation layer 30, a mask layer 70, a planarization layer 40, a bottom electrode 80, an organic light-emitting layer 50 and a top electrode 60 from the bottom to the top. In this embodiment, the bottom electrode 80, the organic light-emitting layer 50 and the top electrode 60 constitute an OLED light-emitting component, and the OLED light-emitting component can be a positive OLED component, then the bottom electrode 80 is an anode, and the top electrode 60 is a cathode. In addition, the OLED component of this embodiment can also include a hole injection layer, a hole transport layer, an electron injection layer and an electron transport layer, wherein the anode, the hole injection layer, the hole transport layer, the organic light-emitting layer 60, the electron transport layer, the electron injection layer and the cathode are stacked in sequence. It should be noted that in other embodiments, the OLED component can also be an inverted OLED component, the bottom electrode 80 is a cathode, and the top electrode 60 is an anode.

[0051] Figure 6 A schematic diagram of the cutting position in a pixel structure, such as Figure 5 As shown, P1, P2, and P3 are commonly used cutting points, but the structures of these cutting points are different. For cutting points P1 and P3, there is only a top electrode (cathode) but no bottom electrode. For cutting point P2, there is a top electrode and a bottom electrode, the top electrode is the cathode, and the bottom electrode is the anode.

[0052] In one embodiment of the present invention, a method for preparing an OLED display panel is provided, the method comprising the following steps:

[0053] Preparing a circuit layer on a substrate, wherein the circuit layer includes a TFT region;

[0054] Sequentially preparing a passivation layer and a planarization layer on the circuit layer;

[0055] Sequentially preparing an organic light-emitting layer and a top electrode on the planarization layer;

[0056] During the preparation process, a mask layer is arranged with the circuit layer, the passivation layer or the planarization layer as a base plate, so that the mask layer is sandwiched between the organic light-emitting layer and the circuit layer, and the mask layer is used to absorb laser energy.

[0057] Specifically, it can be deposited on the substrate

[0058] Optionally, setting the mask layer includes the following steps:

[0059] Determine the base plate of the mask layer;

[0060] Using the area on the bottom plate vertically corresponding to the TFT area as a light shielding area;

[0061] A light-shielding film is provided in the light-shielding area to obtain a mask layer.

[0062] The bottom plate may be the circuit layer, the passivation layer or the planarization layer.

[0063] Optionally, the mask layer is located between the circuit layer and the planarization layer, and before the organic light-emitting layer and the top electrode are sequentially prepared on the planarization layer, the method further includes:

[0064] A bottom electrode is prepared on the planarization layer.

[0065] The bottom electrode is a metal layer, and etching and other processes are usually used. If the bottom plate for preparing the bottom electrode is a mask layer, the mask layer is easily damaged, affecting the shading effect. Therefore, when it is necessary to prepare the bottom electrode, the planarization layer is used as the bottom plate of the bottom electrode, and the mask layer can only be located between the circuit layer and the planarization layer.

[0066] The present invention further provides a display device, the display device comprising the above-mentioned OLED display panel or the OLED display panel prepared by the above-mentioned method for preparing the OLED display panel. The specific structure of the OLED display panel refers to the above-mentioned embodiment. Since the present display device adopts all the technical solutions of all the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0067] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0068] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An OLED display panel, characterized in that: The OLED display panel is a multi-layer structure, which includes a substrate, a circuit layer, a passivation layer, a planarization layer, an organic light-emitting layer and a top electrode from the bottom to the top; the circuit layer includes a TFT area; The OLED display panel further comprises a mask layer, which is sandwiched between the organic light-emitting layer and the circuit layer, and is used for absorbing laser energy.

2. The OLED display panel according to claim 1, wherein: The thickness of the mask layer is positively correlated with the thickness of the TFT region.

3. The OLED display panel according to claim 1, wherein: The mask layer is located between the planarization layer and the passivation layer.

4. The OLED display panel according to claim 1, wherein: The mask layer includes a light shielding film, which corresponds to the position of the TFT region in a vertical direction, and an area of ​​the light shielding film is smaller than or equal to an area of ​​the passivation layer and the planarization layer, and larger than or equal to an area of ​​the TFT region.

5. The OLED display panel according to claim 4, characterized in that: The color of the light-shielding film is red.

6. The OLED display panel according to any one of claims 1 to 5, characterized in that: The OLED display panel further includes a bottom electrode, which is disposed between the planar layer and the organic light-emitting layer.

7. A method for preparing an OLED display panel, characterized in that: The following steps are involved: Preparing a circuit layer on a substrate, wherein the circuit layer includes a TFT region; Sequentially preparing a passivation layer and a planarization layer on the circuit layer; Sequentially preparing an organic light-emitting layer and a top electrode on the planarization layer; During the preparation process, a mask layer is arranged with the circuit layer, the passivation layer or the planarization layer as a base plate, so that the mask layer is sandwiched between the organic light-emitting layer and the circuit layer, and the mask layer is used to absorb laser energy.

8. The method according to claim 7, characterized in that Setting the mask layer includes the following steps: Determine the base plate of the mask layer; Using the area on the bottom plate vertically corresponding to the TFT area as a light shielding area; A light-shielding film is provided in the light-shielding area to obtain a mask layer.

9. The method according to claim 7, characterized in that The mask layer is located between the circuit layer and the planarization layer. Before the organic light emitting layer and the top electrode are sequentially prepared on the planarization layer, the method further includes: A bottom electrode is prepared on the planarization layer.

10. A display device, characterized in that: The display device comprises the OLED display panel according to any one of claims 1 to 6.

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