Display panel and preparation method and driving method thereof

Abstract

The application relates to the technical field of display, and provides a display panel and a preparation method and a driving method thereof. The preparation method comprises the following steps: providing a driving back plate comprising a first signal line; forming an anode on the driving back plate; forming a first pixel definition part on the anode, covering the edges of the anode, and forming an opening exposing the anode between adjacent first pixel definition parts; forming a via hole penetrating through an insulating layer and exposing the first signal line; forming a first electrode on the sidewall of the first pixel definition part and connecting the first signal line through the via hole; forming a second pixel definition part covering the first pixel definition part and the first electrode and exposing the anode; and when inkjet printing a light-emitting material, the liquid drops are dropped on the driving back plate, a voltage is applied to the anode and the first electrode to form an electric field, and the liquid drops formed on the second pixel definition part during the dropping process move to the anode. The application can improve the problem that the liquid drops of the light-emitting material are left on the pixel definition layer during inkjet printing, and realizes accurate positioning of the liquid drops.

Description

Technical Field

[0001] This application belongs to the field of display technology, specifically relating to a display panel and its manufacturing and driving methods. Background Technology

[0002] With the development of optoelectronic display technology, organic light-emitting diode (OLED) display technology has achieved large-scale mass production. In the current OLED panel manufacturing process, evaporation is typically used in conjunction with a photomask to form the OLED luminescent material. However, this method has low material utilization, resulting in a significant waste of expensive materials. Therefore, the technology route of forming OLED luminescent materials using inkjet printing is receiving increasing attention.

[0003] However, during the printing process, it is difficult for the luminescent material droplets to be accurately dropped into the preset pixel openings. Some droplets are prone to remain on the sidewalls or top of the pixel definition layer (PDL), causing crosstalk between adjacent pixels and affecting the display effect. Summary of the Invention

[0004] The purpose of this application is to provide a display panel and its preparation and driving methods, which can improve the problem of light-emitting material droplets remaining on the pixel definition layer during inkjet printing and achieve precise droplet positioning.

[0005] This application provides a display panel, comprising: a driving backplate including a first signal line; an anode disposed on the driving backplate; a first pixel defining portion disposed on the driving backplate, the first pixel defining portion covering the edge region of the anode, and an opening at least partially exposing the anode being formed between adjacent first pixel defining portions, and a via being formed in a region of the first pixel defining portion that does not overlap with the anode, the via penetrating at least one insulating layer and exposing at least a portion of the first signal line; a first electrode disposed on at least the sidewall of the first pixel defining portion and electrically connected to the first signal line through the via; and a second pixel defining portion covering the top of the first pixel defining portion, the sidewall of the first electrode, and the via, and exposing at least a portion of the anode, the first electrode being sandwiched between the first pixel defining portion and the second pixel defining portion; wherein, the first electrode is configured such that: during the inkjet printing of a luminescent material, when a droplet of the luminescent material falls onto the top or sidewall of the second pixel defining portion, an electric field is formed between the first electrode and the anode, driving the droplet to move along the surface of the second pixel defining portion toward the anode.

[0006] In one exemplary embodiment of this application, the first electrode is an electrochromic structure, which includes a first conductive layer, an electrochromic layer, and a second conductive layer stacked together, with the electrochromic layer located between the first conductive layer and the second conductive layer; the driving backplane further includes a second signal line; the first conductive layer is connected to the second signal line, and the second conductive layer is electrically connected to the first signal line; wherein, the electrochromic layer is configured to switch between a reflective state and a transmissive state under the action of a voltage between the first conductive layer and the second conductive layer.

[0007] A second aspect of this application provides a method for manufacturing a display panel as described in any one of the preceding claims, comprising the following steps: providing a driving backplate, the driving backplate including a first signal line; forming an anode on the driving backplate; forming a first pixel definition portion on the driving backplate on which the anode is formed, the first pixel definition portion covering the edge region of the anode, and forming an opening at least partially exposing the anode between adjacent first pixel definition portions; forming a via penetrating at least one insulating layer and exposing at least a portion of the first signal line; forming a first electrode at least on the sidewall of the first pixel definition portion, the first electrode being connected to the first signal line through the via. Electrical connection; forming a second pixel definition portion, the second pixel definition portion covering the top of the first pixel definition portion, the sidewall of the first electrode and the via, and exposing at least a portion of the anode, such that the first electrode is sandwiched between the first pixel definition portion and the second pixel definition portion; during the inkjet printing of luminescent material, droplets of luminescent material are applied to the driving backplate, and a voltage is applied to the anode and the first electrode to form an electric field between the anode and the first electrode. When the droplet falls on the second pixel definition portion, the electric field drives the droplet to move along the surface of the second pixel definition portion toward the anode.

[0008] In one exemplary embodiment of this application, after the step of applying the luminescent material droplets onto the driving backplate and before curing the luminescent material, the method further includes: providing an auxiliary substrate, wherein a common electrode is provided on the auxiliary substrate; assembling the auxiliary substrate and the driving backplate such that the common electrode is disposed opposite to the driving backplate and a gap is formed between the auxiliary substrate and the driving backplate; and applying a voltage to the common electrode to cooperate with the voltage applied to the anode and the first electrode to jointly drive the droplet to move toward the anode.

[0009] In one exemplary embodiment of this application, the auxiliary substrate is further provided with a padding layer, and the padding layer is provided below the common electrode. The padding layer corresponds to the anode, so that the distance between the common electrode and the anode and the distance between the common electrode and the second pixel definition portion are equal after pairing.

[0010] In one exemplary embodiment of this application, the auxiliary substrate is further provided with a support post located in the peripheral area of ​​the auxiliary substrate, which is used to control the minimum distance between the auxiliary substrate and the drive backplate after assembly.

[0011] In one exemplary embodiment of this application, the step of drop-coating luminescent material onto the driving backplate includes: drop-coating luminescent materials of different colors in stages, and applying a voltage to the anode and the first electrode corresponding to each color of luminescent material during drop-coating, so that the droplets formed on the second pixel definition portion during the drop-coating process are driven to the corresponding anode.

[0012] In one exemplary embodiment of this application, the step of forming the second pixel definition portion after forming the first electrode includes: forming a first portion of the second pixel definition portion within the via, the first portion filling the via and having its upper surface flush with the top of the first pixel definition portion; forming a second electrode on the top of the first pixel definition portion, the second electrode being electrically connected to the first electrode; forming a second portion of the second pixel definition portion, the second portion covering at least a portion of the second electrode; the step of applying a voltage to the anode corresponding to each color of luminescent material during drop coating and to the first electrode corresponding to the anode further includes: applying a voltage to the second electrode corresponding to the color, so that the droplet formed on the top of the second pixel definition portion during the drop coating process is driven to the corresponding anode.

[0013] A third aspect of this application provides a driving method for a display panel as described above. In the process of inkjet printing luminescent material, droplets of luminescent material are applied onto the driving backplate, and a voltage is simultaneously applied to the anode and a voltage is applied to the second conductive layer through the first signal line to form an electric field between the anode and the second conductive layer to guide the movement of the droplets. The electric field drives the droplets formed on the second pixel definition portion during the droplet application process to move toward the anode.

[0014] In one exemplary embodiment of this application, after the luminescent material is drop-coated and cured, a display stage is further included: applying a display driving signal to the anode; applying switching voltages to the second conductive layer and the first conductive layer respectively through the first signal line and the second signal line, so that the electrochromic layer switches between a reflective state and a transmissive state, thereby adjusting the display viewing angle and brightness of the display panel.

[0015] The display panel, its fabrication method, and its driving method described in this application have at least the following beneficial effects:

[0016] This application provides a display panel and its fabrication and driving methods. By setting a first pixel defining portion covering the edge region of the anode, and forming a first electrode on the sidewall of the first pixel defining portion, a through-hole penetrating the insulating layer is provided to electrically connect the first electrode to a first signal line in the driving backplate. A second pixel defining portion is then formed covering the first electrode. During inkjet printing of luminescent material, an electric field is formed between the anode and the first electrode by applying a voltage. This electric field drives droplets formed on the second pixel defining portion during the droplet coating process to move towards the anode, effectively overcoming the problem of droplets easily remaining on the sidewall or top of the pixel defining layer, reducing pixel crosstalk caused by droplet residue, achieving precise positioning of luminescent material droplets, improving printing accuracy and material utilization, and thus improving the display quality of the display panel.

[0017] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.

[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0020] Figure 1 A schematic diagram of a method for manufacturing a display panel is shown.

[0021] Figure 2 A schematic diagram of the fabrication process of a display panel is shown.

[0022] Figure 3 A schematic diagram of the process flow is shown, showing the structure with a concave anode.

[0023] Figure 4 A schematic diagram of another method for manufacturing a display panel is shown.

[0024] Figure 5 A schematic diagram of the structural process of another display panel is shown.

[0025] Figure 6 A schematic diagram of the method for combining the auxiliary substrate and the driving backplane is shown.

[0026] Figure 7A schematic diagram of the structural process for forming a display panel using an auxiliary substrate is shown.

[0027] Figure 8 A schematic diagram of the structural process for forming an electrochromic structure on the first pixel definition section is shown.

[0028] Figure 9 A schematic diagram of the electrochromic structure in its reflective state is shown.

[0029] Figure 10 A schematic diagram of the electrochromic structure in the transmission state is shown.

[0030] Figure 11 A schematic diagram of the structure of a display panel is shown.

[0031] Figure 12 A schematic diagram of a structure with a concave shape on the anode is shown.

[0032] Figure 13 A schematic diagram of the connection between the first electrode and the second electrode is shown.

[0033] Explanation of reference numerals in the attached figures:

[0034] 100, Display panel; 110, Driving backplate; 111, First signal line; 112, Substrate; 113, Second signal line; 120, Planarization layer; 130, Anode; 131, Concave structure; 140, First pixel definition portion; 141, Opening; 142, Via; 150, First electrode; 151, Second electrode; 160, Second pixel definition portion; 161, First portion; 162, Second portion; 170, Electrochromic structure; 171, First conductive layer; 172, Electrochromic layer; 173, Second conductive layer; 174, Insulating layer; 180, Light-emitting material droplet; 200, Auxiliary substrate; 210, Substrate; 220, Common electrode; 230, Pad layer; 240, Support pillar. Detailed Implementation

[0035] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0036] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0037] In this application, unless otherwise expressly specified and limited, the terms "assembly," "connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0038] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0039] Example 1

[0040] See 1 and Figure 2 As shown, this application provides a method for manufacturing a display panel 100, comprising the following steps:

[0041] Step S100: Provide the drive backplane 110.

[0042] The driving backplane 110 includes a first signal line 111. The driving backplane 110 can be an LTPS (low-temperature polysilicon) backplane, an oxide backplane, or other types of TFT backplanes. Taking an LTPS backplane as an example, its structure includes a substrate 112, a buffer layer (such as silicon nitride SiNx / silicon oxide SiOx), a polysilicon layer, a gate insulating layer (such as silicon nitride SiNx / silicon oxide SiOx), a first metal layer (gate metal layer), an interlayer insulating layer (such as silicon nitride SiNx / silicon oxide SiOx), a second metal layer (source drain metal layer), and a planarization layer 120 (such as polyimide PI, acrylic, or other organic materials).

[0043] The first signal line 111 can be a trace in the first metal layer or the second metal layer, used to transmit electrical signals to the subsequently formed first electrode 150. The planarization layer 120 has vias exposing the source and drain electrodes, so that the subsequent anode 130 can be connected to the source and drain electrodes.

[0044] For example, if the first signal line 111 is selected as the first metal layer (gate metal layer), then openings need to be reserved at corresponding positions on the planarization layer 120, the interlayer insulating layer, and the gate insulating layer so that the subsequent via 142 can expose the first signal line 111. If the first signal line 111 is selected as the second metal layer (such as the source-drain metal layer), then only openings need to be reserved on the planarization layer 120 to expose the first signal line 111.

[0045] It should be noted that the first signal line 111 is not limited to the first metal layer or the second metal layer. In some other embodiments, when the backplane has multiple metal layers, other metal layers can also be selected.

[0046] In step S200, an anode 130 is formed on the drive backplate 110.

[0047] An anode 130 conductive layer is deposited on the driving backplane 110, and multiple anodes 130 are formed at intervals through a patterning process. The anodes 130 can adopt an ITO / Ag / ITO stacked structure, in which indium tin oxide (ITO) serves as the transparent conductive layer and silver (Ag) serves as the reflective layer. This structure has good conductivity and reflectivity, which helps to improve luminous efficiency. Each anode 130 corresponds to a pixel unit, and the anode 130 is electrically connected to the source and drain (e.g., the drain) through vias on the planarization layer 120, thereby receiving the driving signal of the TFT.

[0048] In other embodiments, such as Figure 3 As shown, before forming the anode 130, a concave structure 131 can be formed on the planarization layer 120 corresponding to the position of the anode 130. This concave structure 131 can be achieved by patterning the planarization layer 120 using a half-exposure process or a grayscale mask process, creating a depression on the surface of the planarization layer 120. Then, the anode 130 material is deposited within the concave structure 131, naturally forming a concave shape. The bottom center region of the concave anode 130 is the lowest, while the edges are higher. With this structure, when a droplet falls onto the anode 130, due to gravity and capillary action, the droplet will automatically converge towards the center, which is beneficial for forming a uniformly thick light-emitting layer. When combined with the subsequent electrowetting effect, the concave structure 131 can further reduce the requirement for electric field strength, improve the efficiency and accuracy of droplet positioning, and also help improve the uniformity of the light-emitting layer.

[0049] In step S300, a first pixel definition portion 140 is formed on the drive backplate 110 on which the anode 130 is formed.

[0050] A first pixel definition layer material, such as PI (polyimide) or PMMA (polymethyl methacrylate), is coated on the driving backplate 110. The pattern of the first pixel definition portion 140 is then formed using a photolithography process. The first pixel definition portion 140 covers the edge region of the anode 130; that is, each anode 130 is surrounded by the first pixel definition portion 140, while the central region of the anode 130 is exposed, forming a pixel opening 141. An opening 141, at least partially exposing the anode 130, is formed between adjacent first pixel definition portions 140. This opening 141 region is the area that the subsequent light-emitting material needs to fill.

[0051] The cross-sectional shape of the first pixel defining portion 140 can be trapezoidal or approximately trapezoidal, with a certain slope on its sidewalls to facilitate the subsequent formation of the first electrode 150. To minimize droplet residue on the top of the pixel defining portion, related designs aim to minimize the top width of the first pixel defining portion 140. However, this often results in a gentler sidewall slope (to maintain a balance between film thickness and opening 141 size), which ironically increases the likelihood of droplet residue on the sidewalls. This application, through a subsequent electrowetting drive scheme, can actively pull droplets remaining on the sidewalls back to the anode 130. Therefore, the shape restrictions on the first pixel defining portion 140 can be relaxed, allowing for a more favorable sidewall slope for process implementation and reducing process complexity.

[0052] Step S400: A via 142 is formed that penetrates at least one insulating layer 174 and exposes at least a portion of the first signal line 111.

[0053] In the first pixel definition portion 140, in the region between adjacent pixel units (i.e., the region that does not overlap with the anode 130), a via 142 penetrating at least one insulating layer 174 is formed by an etching process. Since the first signal line 111 (taking the second metal layer as an example) is located below the planarization layer 120, the via 142 needs to penetrate the first pixel definition portion 140 and the underlying planarization layer 120 until at least a portion of the surface of the first signal line 111 is exposed. If the first signal line 111 is selected as the first metal layer, the via 142 also needs to further penetrate the interlayer insulating layer and the gate insulating layer. The placement of the via 142 needs to be precisely controlled to ensure that it does not overlap with the anode 130, so as to reduce the possibility of a short circuit between the subsequently formed first electrode 150 and the anode 130.

[0054] In this step, such as Figure 2As shown, the via 142 is positioned on the first pixel definition section 140. This utilizes the spatial characteristic that the first pixel definition section 140 covers the edge of the anode 130 but is located outside the anode 130, thus achieving connection with the first signal line 111 while naturally avoiding the risk of short circuit with the anode 130. This layout design fully utilizes the structural characteristics of the pixel definition layer, requires no additional space, and is beneficial for high-resolution pixel design.

[0055] For example, such as Figure 2 As shown, the via 142 can be located at the center of the first pixel definition section 140. This location is far from both anodes 130, minimizing the risk of accidental short circuits with the anodes 130. Simultaneously, sufficient space is left around the via 142 to form the connection between the first electrode 150 and the sidewall, resulting in a larger process window. Of course, the specific location of the via 142 is not strictly limited to the center. As long as it does not overlap with the anodes 130, it can be flexibly adjusted according to the pixel layout and signal line positions. For example, it can be located closer to the end of the first pixel definition section 140 or offset to one side to achieve the same electrical connection function.

[0056] Step S500, as follows Figure 2 As shown, a first electrode 150 is formed at least on the sidewall of the first pixel definition portion 140, and the first electrode 150 is electrically connected to the first signal line 111 through a via 142.

[0057] A first electrode 150 is formed on the sidewall of the first pixel definition portion 140 through deposition and patterning processes. The material of the first electrode 150 can be a metal (such as aluminum (Al), silver (Ag), copper (Cu), etc.) or other conductive materials. For example, the first electrode 150 can be made of a high-reflectivity metal material (such as silver (Ag), so that it can act as a reflective layer during the display stage to reflect the lateral light emitted by the organic light-emitting diode OLED to the front of the panel, thereby improving the brightness when viewed directly.

[0058] The first electrode 150 is not only formed on the sidewall of the first pixel definition portion 140, but also extends into the via 142, directly contacting the first signal line 111 exposed at the bottom of the via 142, thereby achieving electrical connection. During formation, the pattern of the first electrode 150 needs to be controlled so that its side closest to the anode 130 is as close to the anode 130 as possible without contacting it, to reduce the risk of short circuits. For example, the distance between the first electrode 150 and the anode 130 can be controlled within the range of 0.1~2μm. This distance ensures effective electric field formation while reducing the risk of short circuits. If the distance is too small, short circuits are easily caused by process errors; if the distance is too large, the electric field strength weakens, and the driving effect decreases. The range of 0.1~2μm can balance safety and effectiveness under current photolithography precision.

[0059] The formation of the first electrode 150 enables the application of a lateral electric field force to the droplets during subsequent printing, which is a key structure for achieving electrowetting drive. Since the first electrode 150 is located on the sidewall of the first pixel definition portion 140, the electric field it generates is approximately perpendicular to the sidewall and points towards the anode 130, thus providing a direct driving force for the droplets remaining on the sidewall.

[0060] In step S600, a second pixel definition portion 160 is formed, which covers the first pixel definition portion 140 and the first electrode 150, and exposes at least a portion of the anode 130.

[0061] like Figure 2 As shown, after forming the first electrode 150, a second pixel definition layer material is coated to form the second pixel definition portion 160. The material of the second pixel definition portion 160 can be the same as that of the first pixel definition portion 140, such as PI (polyimide), PMMA (polymethyl methacrylate), etc., or a hydrophobic material can be selected, such as a hydrophobic layer of fluoropolymer (Teflon) or a silane monolayer, etc.

[0062] Understandably, using a hydrophobic material for the second pixel defining part 160 can reduce the adhesion of droplets to the pixel defining layer surface, thus making it easier to drive droplet movement under the same electric field strength and reducing the required driving voltage. At the same time, the hydrophobic surface also facilitates the spread of droplets on the anode 130, improving film uniformity.

[0063] The second pixel defining portion 160 covers the entire surface of the first pixel defining portion 140 and the first electrode 150, serving to insulate and protect the first electrode 150. Simultaneously, it fills in the opening area of ​​the first pixel defining portion 140, making the entire pixel defining structure surface more continuous and smooth. At least a portion of the anode 130 is exposed in the second pixel defining portion 160, meaning the pixel opening 141 area remains open to allow for subsequent filling with light-emitting material.

[0064] In other embodiments, to more effectively drive the droplets falling on top of the second pixel definition portion 160 (these droplets are farther from the sidewall first electrode 150 and experience weaker lateral driving forces), such as Figure 4 and Figure 5 As shown, a step-by-step process can be used when forming the second pixel definition part 160:

[0065] In step S610, a first portion 161 of the second pixel definition portion 160 is formed within the via 142, filling the via 142. A planarization process (such as etching back, chemical mechanical polishing (CMP), etc.) is then used to make the upper surface of the first portion 161 flush with the top of the first pixel definition portion 140. The purpose of this is to create a flat surface at the location of the via 142, providing a foundation for the subsequent formation of the top electrode.

[0066] In step S620, a second electrode 151 is formed on top of the first pixel defining portion 140, and the second electrode 151 is electrically connected to the first electrode 150. The second electrode 151 can be formed by depositing a conductive material and patterning it. It is located on top of the first pixel defining portion 140, that is, below the second pixel defining portion 160, so its position corresponds to directly below the top of the subsequently formed second pixel defining portion 160. Since the second electrode 151 is electrically connected to the first electrode 150, both can receive the same voltage signal and work together during the printing process.

[0067] In step S630, a second portion 162 of the second pixel defining portion 160 is formed, which covers at least a portion of the second electrode 151. The second portion 162 of the second pixel defining portion 160 encloses the second electrode 151, providing insulation and protection, while the position of the second electrode 151 corresponds to the area below the top of the second pixel defining portion 160.

[0068] Through the aforementioned step-by-step process, the final structure has two driving electrodes: a first electrode 150 located on the sidewall and a second electrode 151 located on the top. During the droplet coating process, when the droplet lands on the sidewall of the second pixel defining section 160, it is driven by the electric field generated by the first electrode 150; when the droplet lands on the top of the second pixel defining section 160, since the second electrode 151 is located below the top and is at the same potential as the first electrode 150, the electric field generated by the top electrode can effectively act on the top droplet, driving it to the nearest anode 130. This dual-electrode design on the sidewall and top provides comprehensive coverage of possible droplet placement locations, further improving the reliability of droplet positioning, especially for stubborn droplets landing on the top of the PDL.

[0069] In step S700, during the inkjet printing of luminescent material, luminescent material droplets 180 are drop-coated onto the drive backplate 110, and a voltage is applied to the anode 130 and the first electrode 150 to form an electric field between the anode 130 and the first electrode 150. This electric field drives the droplets formed on the second pixel definition portion 160 during the drop-coating process to move toward the anode 130.

[0070] After the above structure is prepared, an inkjet printing process is performed. The luminescent material (such as red R, green G, and blue B organic luminescent material) is droplet-coated onto the driving backplate 110. During the droplet coating process, a positive voltage signal is applied to the anode 130 via TFT control, while a negative voltage signal is applied to the first electrode 150 via the first signal line 111 (or different voltages are applied to create a potential difference), thereby forming an electric field between the anode 130 and the first electrode 150.

[0071] If the droplet is precisely applied onto the anode 130 (i.e., within the pixel opening 141), the droplet itself is unaffected. However, due to the positive voltage applied to the anode 130, the contact angle of the droplet on the anode 130 decreases, which is beneficial for droplet spreading and uniform diffusion. This effect stems from electrowetting: the contact angle of a droplet on a solid surface decreases under an applied voltage, enhancing its spreadability. Therefore, even if the droplet has landed in the correct position, the solution of this application can still improve its film quality.

[0072] If a droplet is deflected and lands on the second pixel definition section 160, it will experience a lateral force pointing towards the anode 130 under the influence of the electric field. This is because droplets in an electric field tend to move towards directions with higher voltage (electrowetting principle), and since the voltage of the anode 130 is higher than that of the first electrode 150, the droplet will move from the surface of the second pixel definition section 160 towards the anode 130 and eventually enter the pixel opening 141. In this way, even with limited printing precision, droplet residue on the pixel definition layer can be effectively reduced, significantly lowering the risk of pixel crosstalk.

[0073] In other embodiments, a batch coating method can be used: different colors of luminescent materials are coated in stages, for example, red R material is coated first, then green G material is coated, and finally blue B material is coated. When coating each color of luminescent material, voltage is applied only to the anode 130 of the pixel unit corresponding to that color and the first electrode 150 corresponding to that anode 130 (if a second electrode 151 is provided, voltage is also applied to the corresponding second electrode 151), while no voltage is applied to the anode 130 and the first electrode 150 of the pixel units of other colors.

[0074] This method can precisely move droplets that are far off-center (e.g., droplets that fall on the top or sidewall of adjacent pixel PDLs) to the desired position, reducing color mixing problems. For example, when dispensing red R material, only the anode 130 and first electrode 150 of the red R pixel have voltage input, while the anode 130 of the green G and blue B pixels has no voltage. If a droplet of red R material falls on the second pixel definition portion 160 of the green G pixel area, since the green G pixel has no electric field, the droplet will not be mistakenly driven into the green G pixel; at the same time, the electric field of the red R pixel area will drive red R material droplets located near the red R pixel to the red R pixel anode 130. Although this selective driving reduces production efficiency (requiring multiple printing operations), it is of great significance for the fabrication of display panels 100 with high precision and high yield requirements.

[0075] To achieve color separation driving, the driver backplane 110 needs to be equipped with multiple signal lines corresponding to different colors, which are respectively connected to the first electrode 150 of the corresponding color pixel. Similarly, if a second electrode 151 is set, corresponding signal lines are also needed for zone control.

[0076] In other embodiments, an auxiliary substrate 200 is introduced after drop coating and before curing the luminescent material to reduce the driving voltage.

[0077] like Figure 6 and Figure 7 As shown, in order to reduce the voltage required to drive the droplets, the following steps can be added after inkjet printing the luminescent material and before curing the luminescent material:

[0078] In step S710, an auxiliary substrate 200 is provided, on which a common electrode 220 is provided. The auxiliary substrate 200 includes a base 210, on which the common electrode 220 is formed. The common electrode 220 can be a transparent conductive layer (such as indium tin oxide ITO) formed over its entire surface, or it can be a patterned electrode layer. The function of the auxiliary substrate 200 is to cooperate with the anode 130 and the first electrode 150 on the back plate to form a dual-plate driving mode.

[0079] In step S720, the auxiliary substrate 200 and the driving backplate 110 are assembled, such that the common electrode 220 is positioned opposite to the driving backplate 110, and a gap is formed between the auxiliary substrate 200 and the driving backplate 110 to accommodate the light-emitting material droplets 180. The assembly precision needs to be controlled to ensure uniform gap, and the minimum spacing can be controlled by setting support pillars 240.

[0080] In step S730, a voltage is applied to the common electrode 220 to coordinate with the voltages applied to the anode 130 and the first electrode 150, jointly driving the droplet towards the anode 130. The addition of the common electrode 220 changes the electric field from unilateral to bilateral driving. A vertical electric field component is formed between the common electrode 220 and the anode 130, and an electric field is also formed between the common electrode 220 and the first electrode 150. This bilateral driving mode can significantly enhance the driving force on the droplet, thereby reducing the driving voltage required for the anode 130 and the first electrode 150 while achieving the same droplet movement effect. This is of great significance for reducing power consumption and simplifying the design of the driving circuit.

[0081] In step S740, after the droplet movement is completed, the auxiliary substrate 200 is removed, and subsequent processes such as curing and encapsulation are continued.

[0082] In some embodiments, a pad height 230 may be provided on the side of the common electrode 220 facing the substrate 210. The distribution position of the pad height 230 corresponds to the anode 130 on the drive backplate 110, and adopts a pattern complementary to the shape of the opening 141 formed by the pixel definition portion. The function of the pad height 230 is to compensate for the height difference of the backplate surface: since the anode 130 area on the backplate is relatively low, while the first pixel definition portion 140 and the second pixel definition portion 160 area are relatively convex, if the auxiliary substrate 200 is flat, the distance from the common electrode 220 to the second pixel definition portion 160 after assembly will be less than the distance from the common electrode 220 to the anode 130, resulting in uneven electric field distribution. By providing the pad height 230 at the position corresponding to the anode 130, the distance from the common electrode 220 to the anode 130 after assembly is made to be substantially equal to the distance from the common electrode 220 to the second pixel definition portion 160, thereby ensuring the uniformity of the electric field distribution in the entire assembly space and making the driving force on the droplet consistent at all locations.

[0083] In some embodiments, support posts 240 may be provided in the peripheral area of ​​the auxiliary substrate 200. The support posts 240 are used to control the minimum distance between the auxiliary substrate 200 and the drive backplate 110 after assembly, ensuring that there is always enough space between them for droplet movement, and reducing contamination caused by the droplets being squeezed or the substrates contacting each other due to excessively tight assembly.

[0084] Finally, the curing of the luminescent material and subsequent processing are completed.

[0085] After the droplet moves to the correct position, the process of solidifying the luminescent material, cathode evaporation, and encapsulation is carried out according to conventional procedures to complete the preparation of the display panel 100.

[0086] Example 2

[0087] like Figure 8 As shown, the difference between Embodiment 2 and Embodiment 1 is that the first electrode 150 in step S500 is replaced with an electrochromic structure 170, so that while realizing the printing assistance function, the viewing angle and brightness of the display stage can also be adjusted, further improving the performance of the display panel 100 and the user experience.

[0088] Among them, such as Figure 9 and Figure 10 As shown, the electrochromic structure 170 includes a first conductive layer 171, an electrochromic layer 172, and a second conductive layer 173 stacked together. The first conductive layer 171 and the second conductive layer 173 are both transparent conductive materials (such as indium tin oxide, ITO), the electrochromic layer 172 is located between the two, and the first conductive layer 171 is located below the second conductive layer 173.

[0089] It should be noted that, in order to ensure electrical isolation between the first conductive layer 171 and the second conductive layer 173 and reduce the possibility of short circuits at their ends, the first conductive layer 171 and the second conductive layer 173 are spaced apart from each other, and an insulating layer 174 is provided at their ends (i.e., the edge area of ​​the electrode pattern). This insulating layer 174 can be made of inorganic insulating materials (such as silicon nitride SiNx, silicon oxide SiOx) or organic insulating materials (such as polyimide PI, polymethyl methacrylate PMMA), and is formed in the overlapping area or possible contact area at the ends of the first conductive layer 171 and the second conductive layer 173 through deposition and patterning processes. The insulating layer 174 effectively prevents accidental short circuits between the first conductive layer 171 and the second conductive layer 173 at their edges due to process deviations or material extension, ensuring that the two conductive layers can be independently voltaged during the printing and display stages without interference, thereby guaranteeing the stable and reversible switching of the electrochromic layer 172 under the action of an electric field. In addition, the introduction of the end insulating layer 174 relaxes the requirements for the patterning accuracy of the first conductive layer 171 and the second conductive layer 173, reduces the process difficulty, and improves the product yield.

[0090] The electrochromic layer 172 can be a thin-film electrochromic material, which may include: a metal hydride electrochromic layer (such as a Mg-Ni alloy, with a Mg:Ni atomic ratio of approximately 7:3 to 8:2), a catalyst layer (such as palladium Pd), a solid electrolyte layer (such as tantalum pentoxide Ta2O5), and an ion storage layer (such as HxWO3). These multilayer films together constitute the electrochromic functional layer, and its working principle is as follows: under the action of an electric field, hydrogen ions migrate in the solid electrolyte, causing the Mg-Ni alloy layer to reversibly switch between a metallic state (high reflectivity state) and a hydride state (transparent state).

[0091] Accordingly, in addition to the first signal line 111 electrically connected to the second conductive layer 173, the drive backplane 110 also includes a second signal line 113 electrically connected to the first conductive layer 171. The first signal line 111 and the second signal line 113 are controlled independently, enabling the electrochromic structure 170 to perform different functions.

[0092] It is understandable that the first signal line 111 and the second signal line 113 can be set on the same layer or on different layers according to the actual needs of the backplane design.

[0093] For example, such as Figure 9 and Figure 10As shown, the first signal line 111 (connected to the second conductive layer 173) and the second signal line 113 (connected to the first conductive layer 171) can both be disposed on the source-drain metal layer (second metal layer), or they can be disposed on different metal layers, for example, the first signal line 111 is disposed on the source-drain metal layer, and the second signal line 113 is disposed on the gate metal layer (first metal layer). This flexible layout design is beneficial for optimizing trace density and adapting to the needs of different resolutions and pixel arrangements. Regardless of whether a same-layer or different-layer layout is adopted, the first signal line 111 and the second signal line 113 should not overlap in the non-display area of ​​the backplane or in the area between pixel units to reduce parasitic capacitance and signal crosstalk. For example, the two should not overlap in the direction perpendicular to the driving backplane 110, or they can be isolated by providing a ground shielding layer.

[0094] Furthermore, similar to the first signal line 111, the second signal line 113 also needs to be electrically connected to the first conductive layer 171 via a via. For example, if the second signal line 113 is located on a metal layer (such as the first or second metal layer) of the drive backplane 110, a via needs to be formed on the corresponding insulating layer 174 (such as the planarization layer 120, interlayer insulating layer, gate insulating layer, etc.) to expose at least a portion of the second signal line 113. This via also needs to be formed in a region avoiding the anode 130, for example, on the first pixel definition portion 140 or in the interval region between the first pixel definition portions 140, ensuring no overlap with the anode 130 and reducing the risk of short circuits. The position, size, and shape of the via can be optimized according to the signal line layout and pixel design, for example, it can be formed in the central or edge region of the first pixel definition portion 140, as long as a reliable electrical connection can be achieved and it does not overlap with the anode 130.

[0095] Through the above layout design, the first signal line 111 and the second signal line 113 can independently and reliably transmit electrical signals to the second conductive layer 173 and the first conductive layer 171, ensuring the normal operation of the electrochromic structure 170 during the printing and display stages, while reducing accidental short circuits with the anode 130 and mutual interference between signals.

[0096] It is worth mentioning that in the circuit layout of the electrochromic structure 170, the relative positions of the first signal line 111 and the second signal line 113, and the direction of the via opening 141, have a significant impact on the driving effect during the printing stage. For example, the first signal line 111 can be arranged between the second signal lines 113, meaning that multiple first signal lines 111 are spatially separated or surrounded by the second signal lines 113. In this layout, the via of the first conductive layer 171 used to connect the second signal line 113 opens towards the anode 130 end, meaning the via connecting the first conductive layer 171 and the second signal line 113 is located on the side closer to the anode 130; correspondingly, the gap between the second conductive layer 173 and the anode 130 is relatively large.

[0097] This layout may increase the distance between the second conductive layer 173 and the anode 130, thus affecting the driving force of the droplets during the printing stage. To ensure that the droplets can overcome the larger gap and move smoothly towards the anode 130, during inkjet printing, in addition to applying a driving voltage to the second conductive layer 173 through the first signal line 111, an auxiliary voltage can also be applied to the first conductive layer 171 through the second signal line 113. By adjusting the voltage of the first conductive layer 171 (for example, applying a voltage with the same or opposite polarity as the second conductive layer 173), an auxiliary electric field can be formed between the anode 130 and the first conductive layer 171. This auxiliary electric field works in conjunction with the main electric field formed by the second conductive layer 173 to jointly drive the droplets towards the anode 130. This dual-electrode cooperative driving method can effectively compensate for the insufficient driving force that may be caused by the increased gap between the second conductive layer 173 and the anode 130, ensuring that the droplets can still move accurately and quickly to the preset position under electrowetting, thus balancing the flexibility of the circuit layout and the reliability of the printing process.

[0098] The above structure enables the following two driving methods:

[0099] Driving during the printing stage: During the inkjet printing of the luminescent material, a voltage is applied to the second conductive layer 173 via the first signal line 111, and simultaneously to the anode 130, forming an electric field between the anode 130 and the second conductive layer 173. This electric field is used to drive the droplet movement, serving the same function as the aforementioned first electrode 150. At this time, the first conductive layer 171 may not be subjected to a voltage or may be subjected to a reference voltage. Since the electrochromic structure 170 is located on the sidewall of the first pixel definition portion 140, its second conductive layer 173 acts as the driving electrode, and the electric field it generates also points towards the anode 130, effectively driving the droplets on the sidewall.

[0100] The display stage is driven by the following processes: After the luminescent material is deposited, cured, and subsequently encapsulated, the display panel 100 enters the display operation stage. At this time, switching voltages are applied to the second conductive layer 173 and the first conductive layer 171 via the first signal line 111 and the second signal line 113, respectively. By controlling the polarity and magnitude of the applied voltage, the electrochromic layer 172 can switch between a reflective state and a transmissive state.

[0101] Reflective State: When the applied voltage causes the voltage of the second conductive layer 173 to be lower than that of the first conductive layer 171, the Mg-Ni alloy in the electrochromic layer 172 exists in the form of a metallic alloy, exhibiting a high reflectivity state. At this time, light emitted by the organic light-emitting diode (OLED) that is directed towards the sidewalls is reflected back to the front of the panel by the electrochromic layer 172, such as... Figure 9 As shown, this increases the brightness in the direct viewing direction. This mode is suitable for scenarios requiring high brightness, such as outdoor use.

[0102] Transmissive state: When the applied voltage makes the voltage of the second conductive layer 173 higher than that of the first conductive layer 171, the Mg-Ni alloy converts to MgNiHx hydride, exhibiting a transparent state. At this time, light from the sidewall direction can be transmitted, such as... Figure 10 As shown, this increases the viewing angle. This mode is suitable for scenarios requiring a wide viewing angle, such as indoor viewing with multiple people.

[0103] By applying different voltages at different stages, the electrochromic structure 170 achieves a dual function: serving as a driving electrode during manufacturing and as an optical adjustment layer during display. This integrated design not only simplifies the structure but also gives the display panel 100 the ability to dynamically adjust viewing angle and brightness, improving product performance and user experience.

[0104] It is understood that the electrochromic layer 172 is not limited to the aforementioned Mg-Ni alloy system; other reversible electrochromic materials are also applicable, such as inorganic electrochromic materials like WO3 (tungsten oxide) and NiO (nickel oxide), or organic electrochromic materials like violetin. As long as reversible switching between the reflection and transmission states can be achieved under the action of an electric field, it can be applied to the technical solution of this application.

[0105] Example 3

[0106] like Figures 11 to 13 As shown, this application embodiment also provides a display panel 100, which is prepared using the above-described method. The display panel 100 includes:

[0107] The driving backplane 110 includes a first signal line 111. The driving backplane 110 can be a TFT backplane of type LTPS (low temperature polycrystalline silicon), oxide, etc., on which a TFT array and various signal lines are formed.

[0108] Anode 130 is disposed on drive backplate 110, and each anode 130 corresponds to one pixel unit. Anode 130 can adopt an ITO / Ag / ITO stacked structure, or other conductive and reflective materials can be used according to design requirements.

[0109] A first pixel definition portion 140 is disposed on the drive backplate 110, covering the edge region of the anode 130. An opening 141 is formed between adjacent first pixel definition portions 140, at least partially exposing the anode 130. A via 142 is formed in a region of the first pixel definition portion 140 that does not overlap with the anode 130 (e.g., between adjacent pixel units). The via 142 penetrates at least one insulating layer 174 (such as a planarization layer 120, an interlayer insulating layer, etc.) and exposes at least a portion of the first signal line 111.

[0110] A first electrode 150 is disposed on the sidewall of at least the first pixel definition portion 140 and electrically connected to the first signal line 111 through a via 142. The first electrode 150 is close to but insulated from the anode 130, and the distance between them can be controlled to be 0.1~2μm. Preferably, the first electrode 150 can be made of a high-reflectivity metal material to improve display brightness.

[0111] The second pixel defining portion 160 covers the first pixel defining portion 140 and the first electrode 150, and exposes at least a portion of the anode 130. The second pixel defining portion 160 may be made of a hydrophobic material to reduce droplet adhesion. The surface of the second pixel defining portion 160 is the area that may come into contact with the droplets during droplet coating.

[0112] The first electrode 150 is configured to form an electric field with the anode 130 to guide the droplets toward the anode 130 during the inkjet printing of the luminescent material.

[0113] In other embodiments, the display panel 100 may further include a second electrode 151 disposed on top of the first pixel defining portion 140 and below the second pixel defining portion 160, and electrically connected to the first electrode 150. The second electrode 151 is used to drive droplets falling on top of the second pixel defining portion 160, and works in cooperation with the first electrode 150 to form an omnidirectional droplet driving capability.

[0114] In some other embodiments, the first electrode 150 can be an electrochromic structure 170, which includes a first conductive layer 171, an electrochromic layer 172, and a second conductive layer 173 stacked together, with the electrochromic layer 172 located between the first conductive layer 171 and the second conductive layer 173. The driving backplane 110 also includes a second signal line 113, with the first conductive layer 171 electrically connected to the second signal line 113 and the second conductive layer 173 electrically connected to the first signal line 111. The electrochromic layer 172 is configured to switch between a reflective state and a transmissive state under the influence of a voltage between the first conductive layer 171 and the second conductive layer 173. This structure enables the display panel 100 to not only have the electrowetting assistance function during the manufacturing stage but also the optical adjustment capability during the display stage.

[0115] In the product structure of the display panel 100, in addition to the aforementioned driving backplate 110, anode 130, first pixel definition section 140, first electrode 150, second pixel definition section 160, and optional second electrode 151 or electrochromic structure 170, the display panel 100 also includes a cathode (not shown in the figure) and an encapsulation layer (not shown in the figure).

[0116] The cathode is disposed above the light-emitting material layer and serves as the counter electrode of the OLED device. The cathode can be a transparent conductive material (such as indium tin oxide (ITO) or indium zinc oxide (IZO)) or a translucent metal thin layer (such as Mg:Ag alloy) to allow light emission. The cathode typically covers the entire display area and provides a common potential to the OLED device via cathode power lines connected to the driving backplane 110. An encapsulation layer is disposed above the cathode to prevent water and oxygen corrosion and protect the OLED device. The encapsulation layer can employ a thin-film encapsulation structure, including alternating inorganic encapsulation layers (such as silicon nitride (SiNx), silicon oxide (SiOx), and aluminum oxide (Al2O3)) and organic encapsulation layers (such as acrylic and epoxy resin) to form an effective water and oxygen barrier. Alternatively, a cover plate encapsulation method can be used, where a cover plate is bonded to the driving backplane 110 using sealant, and the interior is filled with a desiccant or inert gas.

[0117] Through the coordinated operation of the above layers, the display panel 100 of this application not only possesses the electrowetting-assisted printing function during the manufacturing process, but also achieves stable light-emitting performance and long-term reliability. The specific materials and structures of the cathode and encapsulation layer can be selected and optimized according to the type of display panel 100 (top-emitting, bottom-emitting, or double-sided emitting) and encapsulation requirements.

[0118] Example 4

[0119] Corresponding to the display panel 100 of the electrochromic structure 170 described above, embodiments of this application also provide its driving method.

[0120] The driving method during the printing stage: During the inkjet printing of the luminescent material, luminescent material droplets 180 are drop-coated onto the driving backplate 110. Simultaneously, a voltage is applied to the anode 130 and through the first signal line 111 to the second conductive layer 173, thereby forming an electric field between the anode 130 and the second conductive layer 173 to guide the movement of the droplets. This electric field drives the droplets formed on the second pixel definition portion 160 during the drop-coating process to move towards the anode 130. During this stage, the first conductive layer 171 may be unpowered or powered by a reference voltage, and the electrochromic layer 172 remains in any state (either a transmissive or reflective state, without affecting printing).

[0121] The driving method during the display stage: After the luminescent material droplets 180 are deposited and cured, the display panel 100 enters the display stage. At this time, a display driving signal (used to control the brightness of the pixels) is applied to the anode 130, and simultaneously, switching voltages are applied to the second conductive layer 173 and the first conductive layer 171 through the first signal line 111 and the second signal line 113, respectively. By controlling the polarity and amplitude of the switching voltage, the electrochromic layer 172 switches between a reflective state and a transmissive state.

[0122] When a high-brightness mode is needed, a switching voltage is applied to put the electrochromic layer 172 into a reflective state. At this time, light from the sidewall direction is reflected back to the front, such as... Figure 9 As shown, the brightness is increased when viewed directly; when a wide-viewing-angle mode is needed, a switching voltage is applied to put the electrochromic layer 172 into a transmission state, at which point light from the sidewall direction is transmitted, as shown. Figure 10 As shown, the viewing angle is increased.

[0123] In this way, the viewing angle and brightness of the display panel 100 can be dynamically adjusted according to the actual usage scenario (such as indoor / outdoor, single / multiple viewers) to meet different display needs. The switching voltage can be DC voltage or pulse voltage, and the specific waveform and amplitude are optimized according to the characteristics of the electrochromic material.

[0124] In the description of this specification, references to terms such as "some embodiments," "exemplarily," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. The illustrative expressions of the above terms in this specification do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0125] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application. Therefore, any changes or modifications made in accordance with the claims and description of this application should fall within the scope of this patent application.

Claims

1. A display panel, characterized in that, include: A drive backplane, the drive backplane including a first signal line; The anode is disposed on the drive backplate; A first pixel definition portion is disposed on the driving backplane. The first pixel definition portion covers the edge region of the anode, and an opening at least partially exposing the anode is formed between adjacent first pixel definition portions. A via is formed in the region of the first pixel definition portion that does not overlap with the anode. The via penetrates at least one insulating layer and exposes at least a portion of the first signal line. A first electrode is disposed on at least the sidewall of the first pixel definition portion and is electrically connected to the first signal line through the via. The second pixel definition portion covers the top of the first pixel definition portion, the sidewall of the first electrode and the via, and exposes at least a portion of the anode. The first electrode is sandwiched between the first pixel definition portion and the second pixel definition portion. The first electrode is configured such that, during the inkjet printing of the luminescent material, when a droplet of the luminescent material falls onto the top or sidewall of the second pixel definition portion, an electric field is formed between the first electrode and the anode, driving the droplet to move along the surface of the second pixel definition portion toward the anode; the first electrode is an electrochromic structure, the electrochromic structure comprising a first conductive layer, an electrochromic layer and a second conductive layer stacked together, the electrochromic layer being located between the first conductive layer and the second conductive layer; The drive backplane also includes a second signal line; The first conductive layer is connected to the second signal line, and the second conductive layer is electrically connected to the first signal line; The electrochromic layer is configured to switch between a reflective state and a transmissive state under the influence of a voltage between the first conductive layer and the second conductive layer.

2. A method for manufacturing a display panel according to claim 1, characterized in that, Includes the following steps: A drive backplane is provided, the drive backplane including a first signal line; An anode is formed on the drive backplate; A first pixel definition portion is formed on the drive backplate on which the anode is formed. The first pixel definition portion covers the edge region of the anode, and an opening that at least partially exposes the anode is formed between adjacent first pixel definition portions. A via is formed that penetrates at least one insulating layer and exposes at least a portion of the first signal line; A first electrode is formed at least on the sidewall of the first pixel definition portion, and the first electrode is electrically connected to the first signal line through the via. A second pixel definition portion is formed, which covers the top of the first pixel definition portion, the sidewall of the first electrode and the via, and exposes at least a portion of the anode, such that the first electrode is sandwiched between the first pixel definition portion and the second pixel definition portion; During the inkjet printing of luminescent material, droplets of luminescent material are applied to the driving backplate, and a voltage is applied to the anode and the first electrode to form an electric field between the anode and the first electrode. When the droplet falls onto the second pixel definition portion, the electric field drives the droplet to move along the surface of the second pixel definition portion toward the anode.

3. The preparation method according to claim 2, characterized in that, After the step of drop-coating the luminescent material onto the drive backplate, and before curing the luminescent material, the method further includes: An auxiliary substrate is provided, wherein a common electrode is provided on the auxiliary substrate; The auxiliary substrate and the driving back plate are assembled together, such that the common electrode is disposed opposite to the driving back plate, and a gap is formed between the auxiliary substrate and the driving back plate. A voltage is applied to the common electrode to work in conjunction with the voltages applied to the anode and the first electrode to drive the droplet toward the anode.

4. The preparation method according to claim 3, characterized in that, The auxiliary substrate is further provided with a padding layer, and the padding layer is provided below the common electrode. The padding layer corresponds to the anode, so that the distance between the common electrode and the anode and the distance between the common electrode and the second pixel definition part are equal after assembly.

5. The preparation method according to claim 3 or 4, characterized in that, The auxiliary substrate is also provided with a support column, which is located in the peripheral area of ​​the auxiliary substrate and is used to control the minimum distance between the auxiliary substrate and the drive backplate after assembly.

6. The preparation method according to claim 5, characterized in that, The step of applying droplets of luminescent material onto the driving backplate includes: Different colors of luminescent material are applied in stages, and when each color of luminescent material is applied, a voltage is applied to the anode and the first electrode corresponding to that color, so that the droplet formed on the second pixel definition part during the application process is driven to the corresponding anode.

7. The preparation method according to claim 6, characterized in that, After forming the first electrode, the step of forming the second pixel definition portion includes: A first portion of the second pixel definition portion is formed within the via, the first portion filling the via and having its upper surface flush with the top of the first pixel definition portion; A second electrode is formed on top of the first pixel definition portion, and the second electrode is electrically connected to the first electrode. A second portion is formed to define a second pixel, the second portion covering at least a portion of the second electrode; The step of applying a voltage to the anode corresponding to each color and the first electrode corresponding to the anode when drop-coating each color of luminescent material further includes: applying a voltage to the second electrode corresponding to the color so that the droplet formed on the top of the second pixel definition portion during the drop-coating process is driven to the corresponding anode.

8. A driving method for a display panel as described in claim 1, characterized in that, During the inkjet printing of luminescent materials, droplets of luminescent materials are applied onto the driving backplate. Simultaneously, a voltage is applied to the anode and to the second conductive layer through the first signal line, thereby forming an electric field between the anode and the second conductive layer to guide the movement of the droplets. The electric field drives the droplets formed on the second pixel definition portion during the droplet application process to move toward the anode.

9. The driving method according to claim 8, characterized in that, After the luminescent material is drop-coated and cured, the process also includes a display stage: A display drive signal is applied to the anode; Switching voltages are applied to the second conductive layer and the first conductive layer via the first signal line and the second signal line, respectively, so that the electrochromic layer switches between a reflective state and a transmissive state, thereby adjusting the display viewing angle and brightness of the display panel.

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