Display panel, manufacturing method for display panel, and vehicle tail lamp

Abstract

Provided in the present disclosure are a display panel, a manufacturing method for a display panel, and a vehicle tail lamp. The display panel comprises: a base substrate; a pixel definition layer, wherein the pixel definition layer is located on one side of the base substrate, and has a plurality of opening portions; a light-emitting unit layer, wherein the light-emitting unit layer is located on the side of the pixel definition layer away from the base substrate, the light-emitting unit layer comprises a plurality of light-emitting units arranged in an array, and the bottom of each light-emitting unit is located in the opening portion; and an insulating layer, wherein the insulating layer is filled between adjacent light-emitting units, the height of the insulating layer on the face away from the base substrate is greater than the height of the light-emitting unit layer on the face away from the base substrate, and an orthographic projection of the insulating layer on the base substrate is located within the range of an orthographic projection of the pixel definition layer on the base substrate.

Description

Display panel, method for manufacturing display panel, and taillight

[0001] This disclosure claims priority to the Chinese patent application with application number 202311585303.X filed on November 24, 2023, entitled “Display panel, method for manufacturing display panel and vehicle taillight”, the entire contents of which are incorporated by reference into this disclosure. Technical Field

[0002] The present disclosure relates to the field of display technology, and in particular to a display panel, a method for manufacturing a display panel, and a vehicle taillight. Background Art

[0003] In recent years, organic light-emitting diode (OLED) display panels have been widely used in the display industry due to their advantages, including thinness, light weight, wide viewing angle, continuously adjustable light color, low cost, low driving voltage, wide operating temperature range, simple production process, high luminous efficiency, self-luminescence, wide viewing angle, fast response, low power consumption, and flexible display. As the applications of OLED products diversify, more and more car taillights are adopting OLED products.

[0004] Summary of the Invention

[0005] The purpose of the embodiments of the present disclosure is to provide a display panel, a method for manufacturing a display panel, and a vehicle taillight. The present disclosure can solve the problem of low pixel aperture ratio of the display panel. The specific technical solution is as follows:

[0006] A first aspect of the present disclosure provides a display panel. The display panel includes:

[0007] substrate;

[0008] a pixel defining layer, the pixel defining layer being located on one side of the base substrate and having a plurality of openings;

[0009] a light-emitting unit layer, the light-emitting unit layer being located on a side of the pixel defining layer away from the base substrate, the light-emitting unit layer comprising a plurality of light-emitting units arranged in an array, the bottoms of the light-emitting units being located in the openings;

[0010] An insulating layer is filled between adjacent light-emitting units, the height of the insulating layer away from the base substrate is higher than the height of the light-emitting unit layer away from the base substrate, and the orthographic projection of the insulating layer on the base substrate is within the range of the orthographic projection of the pixel defining layer on the base substrate.

[0011] In some embodiments, the cross-section of the insulating layer along a direction perpendicular to the substrate is regular or irregular.

[0012] In some embodiments, the regular shape includes a rectangle, a trapezoid, a parallelogram, an inverted trapezoid, or a rectangle with rounded corners on the same side.

[0013] In some embodiments, the display panel further comprises: a plurality of cathodes and an auxiliary cathode;

[0014] The plurality of cathodes are located on a side of the light-emitting unit layer away from the base substrate, and an orthographic projection of a gap between different cathodes on the base substrate overlaps with an orthographic projection of the insulating layer on the base substrate;

[0015] The auxiliary cathode is located on a side of the insulating layer away from the base substrate, and the auxiliary cathode contacts the side surfaces of the cathodes in gaps between different cathodes.

[0016] In some embodiments, a height of the insulating layer away from the base substrate is lower than a height of the cathode away from the base substrate, and higher than a height of the cathode close to the base substrate.

[0017] In some embodiments, a height of the auxiliary cathode away from a side of the base substrate is higher than a height of the cathode away from a side of the base substrate.

[0018] In some embodiments, the auxiliary cathode further contacts a surface of the cathode away from the base substrate.

[0019] In some embodiments, the orthographic projection of the insulating layer on the base substrate is located within the orthographic projection range of the auxiliary cathode on the base substrate.

[0020] In some embodiments, along a direction perpendicular to the base substrate, a first width of the insulating layer is less than 1 mm, and a second width of the auxiliary cathode is greater than 1.2 mm.

[0021] In some embodiments, the auxiliary cathode has a regular or irregular cross-section along a direction perpendicular to the substrate.

[0022] In some embodiments, the regular shape includes a rectangle, a trapezoid, a parallelogram, an inverted trapezoid, or a rectangle with rounded corners on the same side.

[0023] In some embodiments, a corner of the auxiliary cathode away from the base substrate is rounded or chamfered.

[0024] In some embodiments, the light-emitting unit layer includes a hole transport layer, a first light-emitting material layer, and an electron transport layer sequentially stacked on the pixel defining layer.

[0025] In some embodiments, the light-emitting unit layer further satisfies one or more of the following:

[0026] The light-emitting unit layer further includes a second light-emitting material layer and a charge generation layer, wherein the first light-emitting material layer, the charge generation layer and the second light-emitting material layer are located between the electron transport layer and the hole transport layer, the charge generation layer includes a negative charge generation layer and a positive charge generation layer, and the thickness of the first light-emitting material layer and the second light-emitting material layer are equal or unequal;

[0027] Alternatively, the light-emitting unit layer further includes a hole injection layer and a hole blocking layer, the hole injection layer is located on a side of the hole transport layer close to the base substrate, and the hole blocking layer is located on a side of the electron transport layer close to the base substrate.

[0028] In some embodiments, the first light-emitting material layer and the second light-emitting material layer are red light-emitting materials, and the color coordinates Rx>0.702.

[0029] In some embodiments, the display panel further satisfies one or more of the following:

[0030] The thickness of the hole injection layer is The thickness of the hole transport layer is The thickness of the first light emitting material layer is The thickness of the negative charge generating layer is The thickness of the positive charge generating layer is The thickness of the second light-emitting material layer is The thickness of the hole blocking layer is The thickness of the electron transport layer is The cathode of the display panel includes a first conductive layer and a second conductive layer, and the thickness of the second conductive layer is The thickness of the first conductive layer is

[0031] Alternatively, the display panel includes a plurality of display pixels, each of the display pixels includes at least one light-emitting unit, and a spacing between the display pixels is less than 0.2 mm.

[0032] In some embodiments, the cathode satisfies one or more of the following:

[0033] The cathode includes a first conductive layer, wherein the material of the first conductive layer is a single metal or an alloy;

[0034] The cathode includes a first conductive layer and a second conductive layer, the second conductive layer is arranged close to the base substrate, the material of the first conductive layer is a single metal or an alloy, and the material of the second conductive layer is metal ytterbium;

[0035] Alternatively, the display panel further includes an anode, the anode is a transparent electrode, and the cathode is a reflective electrode.

[0036] A second aspect of the present disclosure provides a method for manufacturing a display panel, which is used to manufacture the display panel described above, comprising the following steps:

[0037] providing a substrate;

[0038] forming a pixel defining thin film layer on one side of the base substrate, and etching the pixel defining thin film layer to form a pixel defining layer having a plurality of openings;

[0039] forming a light-emitting unit layer on a side of the pixel defining layer away from the base substrate, wherein the light-emitting unit layer includes a plurality of light-emitting units arranged in an array, and the bottoms of the light-emitting units are located in the openings;

[0040] An insulating layer is formed on a side of the light-emitting unit layer away from the base substrate, so that the insulating layer fills between adjacent light-emitting units, the height of the insulating layer away from the base substrate is higher than the height of the light-emitting unit layer away from the base substrate, and the orthographic projection of the insulating layer on the base substrate is located within the orthographic projection range of the pixel defining layer on the base substrate.

[0041] In some embodiments, forming a light-emitting unit layer on a side of the pixel defining layer away from the base substrate includes:

[0042] forming a light-emitting unit thin film layer on a side of the pixel defining layer away from the base substrate;

[0043] The method further comprises:

[0044] forming a cathode thin film layer on a side of the light emitting unit layer away from the base substrate;

[0045] Depositing a layer of photoresist on a side of the cathode thin film layer away from the substrate, wherein the photoresist covers the cathode thin film layer;

[0046] removing the first portion of the photoresist by exposure and development, and retaining the second portion of the photoresist, wherein the orthographic projection of the opening on the base substrate is located within the orthographic projection range of the second portion of the photoresist on the base substrate;

[0047] Using the photoresist of the second portion as a mask, etching the cathode thin film layer and the light-emitting unit thin film layer to form etching holes, thereby obtaining the plurality of cathodes and the light-emitting unit layer, wherein the etching holes extend to the surface of the pixel defining layer away from the base substrate, and the etching holes form intervals between adjacent light-emitting units and gaps between different cathodes, wherein the orthographic projection of the gaps between different cathodes on the base substrate overlaps with the orthographic projection of the insulating layer on the base substrate;

[0048] The step of forming an insulating layer on a side of the light emitting unit layer away from the base substrate comprises:

[0049] Filling the etched hole with an insulating layer, wherein the height of the insulating layer at a side away from the substrate is higher than the height of the cathode at a side close to the substrate, and lower than the height of the cathode at a side away from the substrate;

[0050] The method further comprises:

[0051] An auxiliary cathode is formed on a side of the insulating layer away from the base substrate, and the auxiliary cathode contacts the side surfaces of the cathode in the gaps between different cathodes.

[0052] A third aspect of the present disclosure provides a vehicle taillight, comprising the display panel described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] FIG1 is a schematic structural diagram of a display panel provided in an embodiment of the present disclosure;

[0054] FIG2 is a top view of a display panel provided in an embodiment of the present disclosure;

[0055] FIG3 is a schematic diagram showing a comparison of life evaluation of display panels manufactured using conventional technology and photolithography technology at room temperature;

[0056] FIG4 is a schematic diagram showing a comparison of the life evaluation of display panels manufactured using conventional technology and photolithography technology at a high temperature of 85°C;

[0057] FIG5 is a schematic diagram comparing the temperature rise of display panels made using conventional technology and photolithography technology;

[0058] FIG6 shows another variation of the auxiliary cathode in the display panel provided by the embodiment of the present disclosure;

[0059] FIG7 shows another variation of the auxiliary cathode of the display panel provided by the embodiment of the present disclosure;

[0060] FIG8 shows another variation of the auxiliary cathode of the display panel provided by the embodiment of the present disclosure;

[0061] FIG9 shows another deformation of the insulating layer of the display panel provided by the embodiment of the present disclosure;

[0062] FIG10 shows another variation of the insulating layer of the display panel provided by the embodiment of the present disclosure;

[0063] FIG11 shows another variation of the insulating layer of the display panel provided by the embodiment of the present disclosure;

[0064] FIG12 is a schematic diagram of stacking layers of a display panel provided in an embodiment of the present disclosure;

[0065] FIG13 is a schematic diagram of stacking layers in another embodiment of a display panel provided by an embodiment of the present disclosure;

[0066] FIG14 is a schematic diagram of the steps for manufacturing a display panel, wherein a pixel defining layer, an anode, and a light-emitting unit thin film layer are sequentially formed on a base substrate;

[0067] FIG15 is a schematic diagram of the steps for manufacturing a display panel, wherein a cathode thin film layer is deposited on the light-emitting unit thin film layer;

[0068] FIG16 is a schematic diagram showing the steps of manufacturing a panel, wherein a photoresist is deposited on the cathode thin film layer;

[0069] FIG17 is a schematic diagram of the steps for manufacturing a display panel, wherein the light-emitting unit thin film layer and the cathode thin film layer are etched to form etching holes;

[0070] FIG18 is a schematic diagram of the steps for manufacturing a display panel, in which an insulating layer is filled in the etched hole. DETAILED DESCRIPTION

[0071] The following will be combined with the accompanying drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field based on the present disclosure are within the scope of protection of the present disclosure.

[0072] Compared to light-emitting diode (LED) taillights, OLED taillights offer advantages such as low heat generation, thinner screens, and greater design freedom. Consequently, they are increasingly being adopted by both high-end and low-end car models. The OLED taillight market is currently highly competitive, with stricter requirements for product optical lifespan and reliability. Consequently, the performance stability of OLED taillights still needs to be improved. Furthermore, the pixel density (PPI) of OLED taillights is currently low, which affects the display brightness.

[0073] In view of this, the present disclosure provides a display panel. As shown in FIG1 , the display panel includes: a base substrate 100 , a pixel defining layer 102 , a light emitting unit layer 103 , and an insulating layer 106 .

[0074] The pixel defining layer is located on one side of the base substrate. The pixel defining layer has multiple openings. Accordingly, as shown in Figure 1, the portion of the pixel defining layer 102 without openings can be referred to as the main body 102a of the pixel defining layer 102. The pixel defining layer is used to define the precise flow of the solution dissolving the material used to form the light-emitting unit into the designated pixel area during inkjet printing. This designated pixel area is the area defined by the openings of the pixel defining layer.

[0075] The light-emitting unit layer is located on the side of the pixel defining layer away from the base substrate. The light-emitting unit layer includes a plurality of light-emitting units arranged in an array. The bottom of the light-emitting unit is located in the opening portion. The bottom of the light-emitting unit is the portion of the light-emitting unit close to the base substrate. In this way, the solution of the material used to form the light-emitting unit is equivalent to forming a light-emitting unit layer on the side of the pixel defining layer away from the base substrate under the limiting effect of the opening portion of the pixel defining layer, and each opening portion is used to limit the formation of a light-emitting unit. Optionally, the light-emitting unit is a red light-emitting unit, which can emit red light, so that the display panel can also emit red light. For example, the light-emitting unit can emit deep red light, and its color coordinate Rx>0.702. In this way, the display panel has a warning function because it can emit red light, for example, it can be used as a warning light and a tail light.

[0076] The insulating layer 106 is filled between adjacent light-emitting units, that is, the insulating layer 106 fills the gaps 105 between adjacent light-emitting unit layers. The height of the insulating layer away from the substrate is higher than the height of the light-emitting unit layer away from the substrate, and the orthographic projection of the insulating layer on the substrate is within the orthographic projection of the pixel-defining layer on the substrate. Optionally, the insulating layer 106 can be formed by inkjet printing. For example, the height h of the insulating layer 106 satisfies the following conditions: 0.470 μm < h < 0.591 μm.

[0077] According to the characteristics of the insulating layer, it can be concluded that the insulating layer can separate different light-emitting units, thereby preventing lateral current from occurring between different light-emitting units due to contact, and helping to improve the performance stability of the display panel.

[0078] In one possible implementation, as shown in FIG1 , the display panel further includes a plurality of anodes 101, a plurality of cathodes 104, and an auxiliary cathode 107. The plurality of anodes 101 are located on a side of the pixel defining layer close to the base substrate 100. The plurality of anodes 101 are spaced apart on the base substrate. For example, the plurality of openings of the pixel defining layer 102 correspond one-to-one to the anodes 101, and expose at least a portion of the anodes 101. Since each opening is used to define and form a light-emitting unit, the bottom of the light-emitting unit whose bottom is located in the opening can contact the anode 101.

[0079] Multiple cathodes 104 are located on the side of the light-emitting unit layer away from the substrate. The multiple cathodes 104 correspond one-to-one with the multiple anodes 101. In this way, the corresponding cathodes 104 and anodes 101 can power the corresponding light-emitting units, causing the light-emitting units to emit light under the power provided by the cathodes 104 and anodes 101. There are gaps between the different cathodes. The orthographic projections of the gaps between the different cathodes on the substrate overlap with the orthographic projections of the insulating layer on the substrate.

[0080] The auxiliary cathode 107 is located on the side of the insulating layer 106 away from the base substrate 100. The auxiliary cathode 107 overlaps at least partially with the cathode 104. That is, the auxiliary cathode contacts the side of the cathode in the gap between different cathodes. In this way, the auxiliary cathode 107 can achieve electrical connection between different cathodes, thereby connecting all display pixels in the display panel in series and ensuring that the electrical signal provided by the cathode is applied to each display pixel.

[0081] The display panel of the present disclosure may be a self-luminous display panel, such as an organic light-emitting diode (OLED) display panel. The display panel includes a drive circuit layer and a display device layer stacked on a base substrate 100. The display device layer is configured to emit light. The drive circuit layer is configured to drive the display device layer to emit light. The drive circuit layer includes a plurality of thin film transistors 200. The display device layer includes a plurality of self-luminous light-emitting units.

[0082] The display device layer consists of multiple independent light-emitting units formed through a photolithography process and multiple cathodes 104 corresponding to each of the light-emitting units. An auxiliary cathode 107 is located above the cathode 104. Auxiliary cathode 107 is used to connect the display pixels of the display panel in series, connecting the independent light-emitting units and cathodes 104 in series to ensure that the circuit switches apply the electrical signals provided by the cathodes to each display pixel.

[0083] As shown in FIG2 , the display panel includes a plurality of display pixels 400, and each display pixel 400 includes at least one light-emitting unit. The spacing S between the display pixels 400 can be optionally less than 0.2 millimeters (mm). For example, the spacing S between the display pixels 400 can be 0.19 mm, 0.18 mm, 0.17 mm, 0.16 mm or 0.15 mm, etc. For a monochrome display panel, one light-emitting unit is one display pixel 400, so the spacing S between the display pixels 400 is the distance between the light-emitting units. The smaller the spacing S between the display pixels 400, the more display pixels 400 can be set per unit area, which is beneficial to improving the brightness of the display panel. The spacing S between the display pixels 400 of the display panel made by conventional vacuum evaporation is usually about 1.0 mm. In the present disclosure, the light-emitting unit and the cathode 104 are prepared by photolithography technology, which significantly reduces the spacing S between the display pixels 400, which is beneficial to improving the brightness of the display panel.

[0084] Compared to the traditional vacuum evaporation process, the photolithography process does not require the use of a fine metal mask. Since the manufacturing accuracy of the photolithography process is significantly higher than the accuracy of evaporation using a fine metal mask, the pixel aperture ratio of the display panel is no longer limited by the manufacturing accuracy of the fine metal mask, thereby greatly improving the pixel aperture ratio of the display panel. For example, the photolithography process can accurately control the size of a single light-emitting unit so that the orthographic projection of the insulating layer 106 used to separate adjacent light-emitting units on the base substrate 100 is located within the orthographic projection range of the main body 102a on the base substrate 100, thereby reducing the distance between adjacent light-emitting units and correspondingly improving the pixel aperture ratio of the display panel, thereby improving the display brightness of the display panel. On the other hand, since the use of a fine metal mask is eliminated, the process cost of display panel preparation is also significantly reduced.

[0085] In some embodiments, the pixel aperture ratio of the display panel of the present disclosure can be increased to greater than or equal to 80%. The increase in the pixel aperture ratio increases the luminous brightness of the display panel under the condition of unchanged current density. For example, for a 2.78-inch deep red OLED bottom-emitting device product, the display brightness is 2000nit, Rx=0.702, the pixel aperture ratio is increased from 50% to 80%, and the display brightness is increased by 60%, that is, from the original 2000nit to 3200nit. Among them, nit is the intensity of light emitted per unit area of ​​the display screen, and the measurement unit is candela / square meter (cd / m 2 ).

[0086] Moreover, the display panel has a brightness life LT70 of 2000 nits (nit) at a temperature of 20°C-30°C, Rx≥0.702, and can reach greater than or equal to 50,000 hrs (hours), which is significantly improved compared to the brightness life LT70 (about 25,000 hrs) of the display panel manufactured by conventional vacuum evaporation technology. LT70 is the life when the display brightness of the display panel decays to 70% of the initial display brightness. Figure 3 is a schematic diagram comparing the life curves of the display panels manufactured by conventional vacuum evaporation technology and the photolithography technology of the disclosed embodiment, both of which display a brightness of 2000 nit at room temperature. As can be seen from Figure 3, the brightness life LT70 of the display panel manufactured by conventional technology is about 25,000 hrs, and the brightness life LT70 of the display panel manufactured by photolithography technology is about 50,000 hrs, and the brightness life of the display panel at room temperature is increased by 200%. It can be seen from this that the display panel manufactured by photolithography technology not only improves the luminous brightness of the display panel, but also extends the service life of the display panel.

[0087] At a temperature of 80°C-90°C, Rx≥0.702, the 2000nit brightness life LT70 can reach greater than or equal to 6500hrs, which is also significantly improved compared to the brightness life LT70 (about 3400hrs) of the display panel manufactured by conventional vacuum evaporation technology. Figure 4 is a schematic diagram of the comparison of the life curves of the display panels manufactured by conventional vacuum evaporation technology and the photolithography technology of the disclosed embodiment, both of which display a brightness of 2000nit at high temperature (85°C). As can be seen from Figure 4, the brightness life LT70 of the display panel made by conventional technology is about 3400hrs, and the brightness life LT70 of the display panel made by photolithography technology is about 6800hrs, and the high-temperature brightness life of the display panel is increased by 200%. It can be seen that the display panel made by photolithography technology not only improves the luminous brightness of the display panel, but also extends the service life of the display panel.

[0088] In addition to increasing the brightness of the display panel, the increased pixel aperture ratio also significantly improves the normal temperature service life and high temperature reliability of the display panel, and reduces the temperature rise of the product. For example, a display panel prepared using conventional vacuum evaporation technology has a pixel aperture ratio of 50% and a display brightness of 2000 nits. The screen current value is ≈230mA, and its current density is ≈18mA / cm 2 , after 1 hour of normal lighting, the screen temperature rises by 14°C. The display panel prepared according to the photolithography technology disclosed in this disclosure has a pixel aperture ratio of ≈80%. When ensuring the display brightness of 2000 nit, the screen current value is ≈140mA, and its current density drops to 11mA / cm 2 After 1 hour of normal lighting, the screen temperature rises by less than 10°C, and the current density reaches 18mA / cm 2When the brightness is adjusted to 3200 nit, the display brightness is increased by 60%, and the screen temperature rise is reduced by about 29% under high brightness. For a comparison of its product characteristics, please refer to Figure 5.

[0089] In one possible implementation, the height of the insulating layer 106 on the side away from the substrate 100 is lower than the height of the cathode 104 on the side away from the substrate 100, and higher than the height of the cathode 104 on the side closer to the substrate 100. Thus, on one hand, the height of the insulating layer 106 on the side away from the substrate 100 is between the side of the cathode 104 closer to the substrate 100 and the side away from the substrate 100, allowing the insulating layer 106 to completely cover the side surfaces of the light-emitting units. The insulating layer 106 can effectively wrap the light-emitting units, effectively isolating the different light-emitting units, preventing lateral current flow between the different light-emitting units due to contact, and preventing short circuits caused by direct contact between the auxiliary cathode and the light-emitting units, further ensuring the performance stability of the display panel. On the other hand, the height difference between the insulating layer 106 and the cathode 104 allows the auxiliary cathode 107 deposited on the cathode 104 to achieve electrical connection with the side of the cathode 104 without covering the surface of the cathode 104. This helps reduce the designed thickness of the auxiliary cathode 107, thereby reducing the overall thickness of the display panel.

[0090] It is understood that, in a direction perpendicular to the base substrate 100, the height of the auxiliary cathode 107 can be flush with the height of the cathode 104, so that the auxiliary cathode 107 and the cathode 104 can be electrically connected entirely through the side surface. In another possible implementation, as shown in FIG1 , the height of the auxiliary cathode 107 away from the base substrate can be higher than the height of the cathode 104 away from the base substrate. In this case, a portion of the auxiliary cathode 107 is electrically connected to the side surface of the cathode 104, and another portion is in contact with the surface of the cathode 104 away from the base substrate 100. When the height of the auxiliary cathode 107 away from the base substrate is higher than the height of the cathode 104 away from the base substrate, the auxiliary cathode 107 has a greater thickness, which can reduce the probability of defects such as breakage of the auxiliary cathode 107 and help reduce electrical resistance. For example, as shown in FIG6 , FIG7 , and FIG8 , when the height of the auxiliary cathode 107 away from the base substrate is higher than the height of the cathode 104 away from the base substrate, a portion of the auxiliary cathode 107 covers the surface of the cathode 104, so that the auxiliary cathode 107 overlaps the cathode 104. The auxiliary cathode 107 overlaps the cathode 104 at one side and at the other, thereby increasing the contact area between the auxiliary cathode 107 and the cathode 104, reducing the contact resistance between the auxiliary cathode 107 and the cathode 104, and improving the connection stability between the auxiliary cathode 107 and the cathode 104. For example, the thickness h of the auxiliary cathode 107 satisfies:

[0091] 1 , 6 and 7 , the orthographic projection of the insulating layer 106 on the base substrate 100 is within the orthographic projection of the auxiliary cathode 107 on the base substrate 100 . That is, the size of the insulating layer 106 does not exceed that of the auxiliary cathode 107 .

[0092] Optionally, as shown in Figures 1, 6, and 7, along a direction perpendicular to the base substrate 100, the first width 1061 of the insulating layer 106 is less than 1.0 mm. For example, the first width 1061 of the insulating layer 106 may be 0.95 mm, 0.9 mm, 0.85 mm, 0.8 mm, etc. The second width 1071 of the auxiliary cathode 107 is greater than 1.0 mm. For example, the second width 1071 of the auxiliary cathode 107 may be 1.18 mm, 1.16 mm, 1.15 mm, etc. In addition, based on the consideration that the auxiliary cathode 107 can effectively connect all display pixels on the display panel in series, the second width 1071 of the auxiliary cathode 107 may be greater than 1.2 mm. The size of the auxiliary cathode 107 may also take into account factors such as electrical connection stability and manufacturing difficulty.

[0093] In some embodiments, the shape of the cross section of the auxiliary cathode 107 along the direction perpendicular to the base substrate 100 is a regular shape or an irregular shape. Among them, regular shapes include quadrilaterals such as rectangles, trapezoids (i.e., regular trapezoids), parallelograms or inverted trapezoids, or regular shapes include rectangles with rounded corners on the same side. A regular trapezoid means that the upper base size is smaller than the lower base size, while an inverted trapezoid is the opposite, and the lower base size is smaller than the upper base size. As shown in Figure 1, the cross section of the auxiliary cathode 107 along the direction perpendicular to the base substrate 100 is a rectangle. Irregular shapes such as "T" shapes, that is, the auxiliary cathode 107 includes not only the part located between adjacent cathodes, but also the part covering the surface of the cathode 104. The "T" shape mentioned in the present disclosure is not a "T" shape in the strict sense, but is close to a "T" shape. As shown in Figures 6, 7 and 8, the auxiliary cathodes 107 are all irregular shapes.

[0094] Optionally, the corners of the auxiliary cathode 107 along the side away from the base substrate 100 are rounded or chamfered. As shown in FIG7 , the corners of the auxiliary cathode 107 along the side away from the base substrate 100 are rounded. When the corners of the auxiliary cathode 107 along the side away from the base substrate 100 are rounded or chamfered, the difficulty of climbing the slope during the deposition of subsequent film layers is reduced, reducing the risk of subsequent film layers breaking at the corners during climbing, thereby improving the yield of the display panel.

[0095] Similarly, the cross-sectional shape of the insulating layer 106 along the direction perpendicular to the base substrate 100 may also be a regular shape or an irregular shape. Regular shapes include quadrilaterals such as rectangles, trapezoids (i.e., regular trapezoids), parallelograms or inverted trapezoids, or regular shapes include rectangles with rounded corners on the same side. As shown in FIG9 , the cross-sectional shape of the insulating layer 106 along the direction perpendicular to the base substrate 100 is a rectangle. As shown in FIG10 , the cross-sectional shape of the insulating layer 106 along the direction perpendicular to the base substrate 100 is a regular trapezoid. As shown in FIG11 , the cross-sectional shape of the insulating layer 106 along the direction perpendicular to the base substrate 100 is a rectangle with rounded corners on the same side. Irregular shapes such as a "T" shape, that is, the insulating layer 106 includes not only the portion located between adjacent light-emitting unit layers 103, but also the portion covering the surface of the light-emitting unit layer 103. The "T" shape mentioned in the present disclosure is not a "T" shape in the strict sense, but is close to a "T" shape.

[0096] Furthermore, the corners of the insulating layer 106 along the side away from the base substrate 100 may also be rounded or chamfered. As shown in FIG11 , the corners of the insulating layer 106 along the side away from the base substrate 100 are rounded. When the corners of the insulating layer 106 along the side away from the base substrate 100 are rounded or chamfered, the difficulty of the auxiliary cathode 107 climbing during the deposition process is reduced, reducing the risk of the auxiliary cathode 107 breaking at the corners due to climbing, thereby improving the yield of the display panel.

[0097] In some embodiments, as shown in Figures 1, 6-8, and 9-11, the light-emitting unit layer includes a hole transport layer (HTL) 1032, a first emitting material layer (EML) 1033, and an electron transport layer (ETL) 1037, which are sequentially stacked on the pixel defining layer. Specifically, the hole transport layer 1032 is located on the side close to the anode 101.

[0098] The hole transport layer 1032, first light-emitting material layer 1033, and electron transport layer 1037 are stacked sequentially, with the hole transport layer 1032 positioned closer to the anode 101 and the electron transport layer 1037 closer to the cathode 104. When current is applied, electrons are injected into the cathode 104, forming holes in the anode 101. The electrons and holes travel toward each other through the layers, eventually meeting and combining in the light-emitting layer, releasing energy as photons. This process occurs rapidly and continuously when current flows, resulting in continuous light emission.

[0099] In some embodiments, as shown in FIG12 , the light-emitting unit layer 103 further includes a second light-emitting material layer 1036. The first light-emitting material layer 1033 and the second light-emitting material layer 1036 are optionally located between the hole transport layer 1032 and the electron transport layer 1037. Optionally, a charge generation layer (CGL) may be provided between the first light-emitting material layer 1033 and the second light-emitting material layer 1036. The charge generation layer may optionally include a positive charge generation layer (PCGL) 1035 and a negative charge generation layer (NCGL) 1034.

[0100] In the disclosed embodiment, the light-emitting unit layer 103 includes two layers of light-emitting material, which can improve the brightness of the display panel. By providing two layers of light-emitting material, the brightness of each layer can be reduced relative to the rated brightness, so that each layer of light-emitting material emits light below the maximum brightness, thereby extending the service life of the light-emitting material.

[0101] The first luminescent material layer 1033 and the second luminescent material layer 1036 can have the same thickness. The two luminescent material layers have the same thickness, so that the luminescence brightness of the two luminescent material layers is consistent. The thickness can be designed to adjust the luminescence brightness of the two luminescent material layers to the optimal brightness.

[0102] Of course, the thicknesses of the first luminescent material layer 1033 and the second luminescent material layer 1036 may also be different. If the thicknesses of the two luminescent material layers are different, one layer can be set as the main luminescent layer and the other as the auxiliary luminescent layer, thereby improving the brightness of the display panel.

[0103] Optionally, the first luminescent material layer 1033 and the second luminescent material layer 1036 are red luminescent materials, and the color coordinate Rx is greater than 0.702. For example, the color coordinate Rx may be 0.708.

[0104] The color coordinates Rx of the first and second luminescent material layers 1033 and 1036 are greater than 0.702, resulting in a deep red luminescence color from the display panel, enhancing warning effects. Furthermore, as the color of the display panel's luminescence deepens, the wavelength of the emitted light also lengthens, making it less susceptible to scattering during propagation, thereby increasing the penetrating power of the emitted light. When the display panel serves as the display component of a car's taillights, the deep red light emitted by the display panel travels farther, providing a better safety warning effect.

[0105] In some embodiments, as shown in FIG12 , the anode 101 is a transparent electrode, for example, made of a conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO); the cathode 104 is an opaque electrode.

[0106] In the disclosed embodiment, the anode can be a transparent electrode, and the cathode 104 can be a reflective electrode. This allows the anode 101 to serve as the light-emitting side of the display panel, making the display panel a bottom-emitting display panel. Compared to top-emitting display panels, bottom-emitting display panels have a simpler structure.

[0107] As shown in FIG12 , cathode 104 optionally includes a first conductive layer 1042. The material of first conductive layer 1042 is a single metal or alloy. Alternatively, cathode 104 includes first conductive layer 1042 and second conductive layer 1041, with second conductive layer 1041 disposed adjacent to substrate 100. The material of first conductive layer 1042 is a single metal or alloy, such as aluminum (Al). The material of second conductive layer 1041 is ytterbium (Yb).

[0108] For example, when the cathode 104 includes a single conductive layer, the material of the conductive layer can be a single metal such as aluminum, copper, gold, silver, etc., or an alloy such as magnesium-silver alloy, aluminum alloy, copper alloy, etc. When the cathode 104 includes two conductive layers, the material of the second conductive layer 1041 disposed close to the base substrate 100 is ytterbium, and the material of the first conductive layer 1042 disposed away from the base substrate 100 is a single metal or alloy. Examples of single metals include aluminum, copper, gold, silver, etc., and examples of alloys include magnesium-silver alloy, aluminum alloy, copper alloy, etc.

[0109] Of course, as shown in FIG12 , the light-emitting unit layer may further include a hole injection layer (HIL) 1031 and a hole blocking layer (HBL) 1038. The hole injection layer 1031 is located on the side of the hole transport layer 1032 close to the anode 101, and the hole blocking layer 1038 is located on the side of the electron transport layer 1037 close to the anode 101. In one possible implementation, the thickness of the hole injection layer 1031 is The thickness of the hole transport layer 1032 is The thickness of the first light emitting material layer 1033 is The thickness of the negative charge generating layer 1034 is The thickness of the positive charge generation layer 1035 is The thickness of the second light emitting material layer 1036 is The thickness of the hole blocking layer 1038 is The thickness of the electron transport layer 1037 is The thickness of the second conductive layer 1041 is The thickness of the first conductive layer 1042 is

[0110] A hole injection layer 1031 is introduced between the anode 101 and the first light-emitting material layer 1033. The hole injection layer 1031 can reduce the energy barrier for holes to be injected from the anode 101 into the first light-emitting material layer 1033. A hole blocking layer 1038 is provided between the second light-emitting material layer 1036 and the electron transport layer 1037 to significantly improve the electron collection rate at the interface. The hole blocking ability of the hole blocking layer 1038 also increases with the increase of its thickness. In addition, since the hole blocking layer 1038 is relatively thin, for example Under the action of the electric field, holes can also tunnel through the thinner hole blocking layer 1038, so it can not only improve the electron transmission rate, but also extend the service life of the OLED device, and is an indispensable product for OLED devices.

[0111] When the cathode 104 includes two conductive layers, the second conductive layer 1041 can have a relatively thin thickness, for example, The first conductive layer 1042 can have a relatively thick thickness, for example, etc., which can increase the electron injection rate through the second conductive layer.

[0112] In the embodiment of the present disclosure, when the bottom-emitting device includes only one layer of luminescent material, such as when the luminescent material emits red, green, or blue light, its structure can be further simplified. For example, FIG13 is a schematic diagram of the structure of a bottom-emitting taillight device with a monochrome design. As shown in FIG13, its structure is simple, consisting of only 7 layers stacked, each with a thickness of The hole injection layer 1031 has a thickness of The hole transport layer 1032 has a thickness of The red emitting layer (REML) is 1033 mm thick. The hole blocking layer 1038 has a thickness of The electron transport layer (ETL) 1037 has a thickness of The second conductive layer 1041 has a thickness of The first conductive layer 1042 is made of 8-hydroxyquinolinolato-lithium (Liq). The hole injection layer 1031 can be made of a material with a thickness of As a result, when a display panel is manufactured using photolithography technology and is a monochrome bottom-emitting device, the total number of film layers is reduced and only one exposure process is required, simplifying the manufacturing process and ensuring product yield.

[0113] For example, for the structure shown in Figure 13, if the device is fabricated using vacuum evaporation according to a conventional OLED fabrication method, with a total display area aperture ratio of 50% and a product brightness of 2000 nits, the brightness lifetime (LT70) is 25,000 hrs and Rx is 0.702 at room temperature (25°C); and 3,400 hrs and Rx is 0.702 at high temperature (85°C). This disclosure upgrades the traditional OLED fabrication method to a photolithography solution, increasing the total display area aperture ratio to 80%. When evaluating the brightness lifetime at 2000 nits, the brightness lifetime (LT70) is 50,000 hrs and Rx is 0.702 at room temperature (25°C); and 6,800 hrs and Rx is 0.702 at high temperature (85°C).

[0114] In the display panel provided by the embodiment of the present disclosure, the light-emitting units and cathode are formed by a photolithography process. Compared with the traditional vacuum evaporation process, the photolithography process does not require the use of a fine metal mask. Since the manufacturing accuracy of the photolithography process is significantly higher than the accuracy of evaporation using a fine metal mask, the pixel aperture ratio of the display panel is no longer limited by the manufacturing accuracy of the fine metal mask, thereby greatly improving the pixel aperture ratio of the display panel. Specifically, the photolithography process can accurately control the size of the light-emitting unit so that the orthographic projection of the insulating layer used to separate adjacent light-emitting units on the substrate is located within the orthographic projection range of the main body on the substrate, thereby reducing the distance between adjacent light-emitting units, improving the pixel aperture ratio of the display panel, and thus improving the display brightness of the display panel. On the other hand, since the use of a fine metal mask is eliminated, the process cost of display panel preparation is significantly reduced.

[0115] The height of the insulating layer away from the substrate lies between the side of the cathode closest to the substrate and the side away from the substrate, allowing the insulating layer to completely cover the side surfaces of the light-emitting unit and the cathode, preventing lateral current flow. This height difference between the insulating layer and the cathode allows the auxiliary cathode deposited on top of the cathode to be electrically connected to the cathode through a side overlap without having to cover the cathode surface. This helps reduce the design thickness of the auxiliary cathode, thereby reducing the overall thickness of the display panel.

[0116] The present disclosure also provides a method for manufacturing a display panel, which is used to manufacture the above display panel. The manufacturing method includes the following steps:

[0117] S1: Provide a substrate.

[0118] S2: forming a pixel defining thin film layer on one side of the base substrate, and etching the pixel defining thin film layer to form a pixel defining layer having a plurality of openings.

[0119] S3: forming a light-emitting unit layer on a side of the pixel defining layer away from the base substrate, wherein the light-emitting unit layer includes a plurality of light-emitting units arranged in an array, and the bottom of the light-emitting unit is located in the opening.

[0120] S4: forming an insulating layer on the side of the light-emitting unit layer away from the base substrate, so that the insulating layer fills between adjacent light-emitting units, the height of the side of the insulating layer away from the base substrate is higher than the height of the side of the light-emitting unit layer away from the base substrate, and the orthographic projection of the insulating layer on the base substrate is within the range of the orthographic projection of the pixel defining layer on the base substrate.

[0121] The present disclosure also provides another method for manufacturing a display panel, which is used to manufacture the above display panel. The manufacturing method includes the following steps:

[0122] S100: providing a base substrate 100.

[0123] S200 : manufacturing a plurality of anodes 101 arranged at intervals on one side of the base substrate 100 .

[0124] S300 : forming a pixel defining layer 102 on a side of the anode 101 away from the base substrate 100 , and etching the pixel defining layer 102 to form a plurality of alternating main portions 102 a and opening portions, wherein the opening portions correspond to the anodes 101 one by one and expose at least part of the anodes 101 .

[0125] S400 : forming a light-emitting unit thin film layer on a side of the pixel defining layer 102 away from the base substrate 100 .

[0126] For example, a light-emitting unit thin film layer 103 is evaporated on a side of the pixel defining layer 102 away from the base substrate 100 under an open mask condition, as shown in FIG14 .

[0127] S500 : forming a cathode thin film layer on a side of the light emitting unit thin film layer away from the base substrate 100 .

[0128] For example, a cathode film layer 104 is deposited under open mask conditions on the side of the light emitting unit film layer 103 away from the base substrate 100, as shown in Figure 15. Both the light emitting unit film layer and the cathode film layer can be deposited by vacuum evaporation process.

[0129] S600: Depositing a layer of photoresist 300 on the side of the cathode film layer 104 away from the substrate 100, the photoresist 300 covers the cathode film layer 104, as shown in Figure 16. The photoresist can be deposited on the side of the cathode film layer away from the substrate 100 by vapor deposition.

[0130] S700: removing the photoresist 300 of the first portion 301 by exposure and development, and retaining the photoresist 300 of the second portion 302. The orthographic projection of the opening on the substrate is within the orthographic projection range of the second portion of the photoresist on the substrate, as shown in FIG16 .

[0131] S800: Using the photoresist 300 of the second part 302 as a mask, the cathode thin film layer and the light-emitting unit thin film layer are etched to form etching holes, and multiple cathodes and light-emitting unit layers are obtained. The etching holes extend to the surface of the main body 102a away from the base substrate 100. The etching holes form intervals 105 between adjacent light-emitting unit layers and gaps between different cathodes, as shown in FIG17 . The orthographic projection of the gaps between different cathodes on the base substrate overlaps with the orthographic projection of the insulating layer on the base substrate. The photoresist 300 of the second part 302 is used to block the laser used during etching to protect the OLED device in the display area. Optionally, the etching depth is 0.591 μm and the etching width is less than 0.2 μm.

[0132] S900: Fill the etched hole with an insulating layer 106 , wherein the height of the insulating layer 106 away from the base substrate 100 is higher than the height of the cathode 104 close to the base substrate 100 and lower than the height of the cathode 104 away from the base substrate 100 , as shown in FIG18 .

[0133] S1000 : forming an auxiliary cathode 107 on a side of the insulating layer 106 away from the base substrate 100 , wherein the auxiliary cathode contacts the side surface of the cathode 104 in the gap between different cathodes, as shown in FIG1 .

[0134] In the embodiment of the present disclosure, the driving layer of the thin film transistor 200 of the display panel is prepared by a commonly used photolithography process, which will not be described in detail here. The light-emitting unit thin film layer and the cathode thin film layer are deposited as a whole layer under open mask conditions, and then the light-emitting unit thin film layer arranged in the whole layer is etched into a plurality of light-emitting units arranged at intervals by a photolithography process, and the cathode thin film layer arranged in the whole layer is etched into a plurality of cathodes 104 arranged at intervals by a photolithography process. The present disclosure adopts an open mask to replace a fine metal mask, which significantly reduces the production cost of the display panel. And because the etching accuracy of the photolithography process is relatively high, the width of the interval 105 between adjacent light-emitting units and adjacent cathodes 104 is smaller than the width of the main body 102a of the pixel defining layer 102, which greatly improves the pixel aperture ratio of the display panel, thereby improving the brightness of the display panel.

[0135] A third aspect of the present disclosure provides a vehicle taillight comprising the display panel provided herein. Because the light-emitting unit layer and cathode 104 of the display panel of the vehicle taillight are fabricated using a photolithography process, compared to conventional vacuum evaporation processes, this eliminates the need for a fine metal mask, significantly reducing the production cost of the display panel. Furthermore, the photolithography process offers high etching precision, significantly increasing the pixel aperture ratio of the display panel and thereby improving the display brightness of the display panel, thereby extending the lifespan of the device and enhancing the user experience.

[0136] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0137] Each embodiment in this specification is described in a related manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

[0138] The above are only preferred embodiments of the present disclosure and are not intended to limit the scope of protection of the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure are included in the scope of protection of the present disclosure.

Claims

1. A display panel, characterized in that: The display panel comprises: substrate substrate; A pixel defining layer, the pixel defining layer is located on one side of the base substrate, and the pixel defining layer has a plurality of openings; A light-emitting unit layer, the light-emitting unit layer is located on a side of the pixel defining layer away from the base substrate, the light-emitting unit layer includes a plurality of light-emitting units arranged in an array, and the bottom of the light-emitting unit is located in the opening; An insulating layer is filled between adjacent light-emitting units, the height of the insulating layer away from the base substrate is higher than the height of the light-emitting unit layer away from the base substrate, and the orthographic projection of the insulating layer on the base substrate is within the range of the orthographic projection of the pixel defining layer on the base substrate.

2. The display panel according to claim 1, characterized in that: The cross-section of the insulating layer along a direction perpendicular to the substrate is in a regular shape or an irregular shape.

3. The display panel according to claim 2, characterized in that: The regular shape includes a rectangle, a trapezoid, a parallelogram, an inverted trapezoid or a rectangle with rounded corners on the same side.

4. The display panel according to any one of claims 1 to 3, characterized in that: The display panel further includes: a plurality of cathodes and auxiliary cathodes; The plurality of cathodes are located on a side of the light-emitting unit layer away from the base substrate, and an orthographic projection of the gaps between different cathodes on the base substrate overlaps with an orthographic projection of the insulating layer on the base substrate; The auxiliary cathode is located at a side of the insulating layer away from the base substrate, and the auxiliary cathode contacts the side surface of the cathode in the gap between different cathodes.

5. The display panel according to claim 4, characterized in that: The height of the insulating layer at a side away from the base substrate is lower than the height of the cathode at a side away from the base substrate, and higher than the height of the cathode at a side close to the base substrate.

6. The display panel according to claim 4 or 5, characterized in that: The height of the auxiliary cathode away from one side of the base substrate is higher than the height of the cathode away from one side of the base substrate.

7. The display panel according to any one of claims 4 to 6, characterized in that: The auxiliary cathode is also in contact with a surface of the cathode away from the base substrate.

8. The display panel according to any one of claims 4 to 7, characterized in that: The orthographic projection of the insulating layer on the base substrate is located within the orthographic projection range of the auxiliary cathode on the base substrate.

9. The display panel according to claim 8, characterized in that: Along a direction perpendicular to the base substrate, a first width of the insulating layer is less than 1 mm, and a second width of the auxiliary cathode is greater than 1.2 mm.

10. The display panel according to any one of claims 4 to 9, characterized in that: The auxiliary cathode has a regular or irregular cross-section along a direction perpendicular to the substrate.

11. The display panel according to claim 10, characterized in that: The regular shape includes a rectangle, a trapezoid, a parallelogram, an inverted trapezoid or a rectangle with rounded corners on the same side.

12. The display panel according to any one of claims 4 to 10, characterized in that: The corner of the auxiliary cathode at a side away from the base substrate is rounded or chamfered.

13. The display panel according to any one of claims 1 to 12, characterized in that: The light-emitting unit layer includes a hole transport layer, a first light-emitting material layer and an electron transport layer sequentially stacked on the pixel defining layer.

14. The display panel according to claim 13, characterized in that: The light-emitting unit layer also satisfies one or more of the following: The light-emitting unit layer further includes a second light-emitting material layer and a charge generation layer, wherein the first light-emitting material layer, the charge generation layer and the second light-emitting material layer are located between the electron transport layer and the hole transport layer, the charge generation layer includes a negative charge generation layer and a positive charge generation layer, and the thickness of the first light-emitting material layer and the second light-emitting material layer are equal or unequal; Alternatively, the light-emitting unit layer further includes a hole injection layer and a hole blocking layer, wherein the hole injection layer is located on a side of the hole transport layer close to the base substrate, and the hole blocking layer is located on a side of the electron transport layer close to the base substrate.

15. The display panel according to claim 14, characterized in that: The first luminescent material layer and the second luminescent material layer are red luminescent materials, and the color coordinates Rx>0.

702.

16. The display panel according to claim 14 or 15, characterized in that: The display panel also satisfies one or more of the following: The thickness of the hole injection layer is The thickness of the hole transport layer is The thickness of the first light emitting material layer is The thickness of the negative charge generating layer is The thickness of the positive charge generating layer is The thickness of the second luminescent material layer is The thickness of the hole blocking layer is The thickness of the electron transport layer is The cathode of the display panel includes a first conductive layer and a second conductive layer, and the thickness of the second conductive layer is The thickness of the first conductive layer is Alternatively, the display panel includes a plurality of display pixels, each of the display pixels includes at least one light-emitting unit, and a spacing between the display pixels is less than 0.2 mm.

17. The display panel according to any one of claims 4 to 16, characterized in that: The cathode satisfies one or more of the following: The cathode comprises a first conductive layer, the material of the first conductive layer is a single metal or an alloy; The cathode comprises a first conductive layer and a second conductive layer, the second conductive layer is arranged close to the substrate, the material of the first conductive layer is a single metal or an alloy, and the material of the second conductive layer is metal ytterbium; Alternatively, the display panel further includes an anode, the anode is a transparent electrode, and the cathode is a reflective electrode.

18. A method for manufacturing a display panel, characterized in that: The method comprises: providing a substrate base plate; A pixel defining thin film layer is formed on one side of the base substrate, and the pixel defining thin film layer is etched to form a pixel defining layer having a plurality of openings; forming a light-emitting unit layer on a side of the pixel defining layer away from the base substrate, wherein the light-emitting unit layer comprises a plurality of light-emitting units arranged in an array, and the bottom of the light-emitting unit is located in the opening; An insulating layer is formed on a side of the light-emitting unit layer away from the base substrate, so that the insulating layer fills between adjacent light-emitting units, a height of the insulating layer away from the base substrate is higher than a height of the light-emitting unit layer away from the base substrate, and an orthographic projection of the insulating layer on the base substrate is within the range of the orthographic projection of the pixel defining layer on the base substrate.

19. The method according to claim 18, characterized in that The light emitting unit layer is formed on a side of the pixel defining layer away from the base substrate, including include: forming a light-emitting unit thin film layer on a side of the pixel defining layer away from the base substrate; The method further comprises: forming a cathode thin film layer on a side of the light-emitting unit layer away from the base substrate; Depositing a layer of photoresist on a side of the cathode film layer away from the substrate, wherein the photoresist covers the cathode film layer; The first portion of the photoresist is removed by exposure and development, and the second portion of the photoresist is retained, wherein the orthographic projection of the opening on the substrate is located within the orthographic projection range of the second portion of the photoresist on the substrate; Using the photoresist of the second portion as a mask, the cathode thin film layer and the light-emitting unit thin film layer are etched to form etching holes, and the plurality of cathodes and the light-emitting unit layer are obtained, wherein the etching holes extend to the surface of the pixel defining layer away from the base substrate, and the etching holes form intervals between adjacent light-emitting units and gaps between different cathodes, and the orthographic projection of the gaps between different cathodes on the base substrate overlaps with the orthographic projection of the insulating layer on the base substrate; The step of forming an insulating layer on a side of the light emitting unit layer away from the base substrate comprises: Filling an insulating layer in the etched hole, wherein the height of the insulating layer at a side away from the substrate is higher than the height of the cathode at a side close to the substrate, and lower than the height of the cathode at a side away from the substrate; The method further comprises: An auxiliary cathode is formed on a side of the insulating layer away from the base substrate, and the auxiliary cathode contacts the side surface of the cathode in the gap between different cathodes.

20. A vehicle taillight, characterized in that: The vehicle taillight comprises a display panel, and the display panel comprises: substrate substrate; A pixel defining layer, the pixel defining layer is located on one side of the base substrate, and the pixel defining layer has a plurality of openings; A light-emitting unit layer, the light-emitting unit layer is located on a side of the pixel defining layer away from the base substrate, the light-emitting unit layer includes a plurality of light-emitting units arranged in an array, the bottom of the light-emitting unit is located in the opening, and the light-emitting unit is a red light-emitting unit; An insulating layer is filled between adjacent light-emitting units, and the insulating layer is far away The height from one side of the base substrate is higher than the height from one side of the light emitting unit layer away from the base substrate, and the orthographic projection of the insulating layer on the base substrate is within the orthographic projection range of the pixel defining layer on the base substrate.

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