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

Abstract

The invention provides a display panel, a manufacturing method of the display panel and a tail lamp. The display panel comprises a substrate, an anode, a pixel defining layer, a light emitting unit, a cathode, an insulating layer and an auxiliary cathode. The anodes are arranged on one side of the substrate and are arranged at intervals. The pixel defining layer is arranged on the side, away from the substrate, of the anode and comprises a body part and opening parts, and the opening parts are in one-to-one correspondence with the anode and expose at least part of the anode. Light-emitting units and cathodes which are in one-to-one correspondence with the anodes are sequentially arranged on the side, away from the substrate, of the pixel defining layer, the light-emitting units are red light-emitting units, insulating layers are arranged between the adjacent light-emitting units, and the orthographic projection of the insulating layers on the substrate is located within the orthographic projection range of the body part on the substrate. And the height of one surface, far away from the substrate, of the insulating layer is between the surfaces, close to and far away from the substrate, of the cathode. The auxiliary cathode is arranged on one side, far away from the substrate, of the insulating layer; and the auxiliary cathode is at least partially lapped with the cathode.

Description

Technical Field

[0001] The present application relates to the field of display technologies, and particularly to a display panel, a manufacturing method of the display panel, and a taillight. Background Art

[0002] In recent years, organic light emitting diode (OLED) display panels have been widely used in the display field due to their advantages such as self-luminescence, wide viewing angle, fast response, low power consumption, and flexible display. With the diversification of OLED product applications, more and more taillights have started to use OLED products. Currently, the pixel PPI (Pixels Per Inch, pixel aperture ratio) of in-vehicle OLED devices is low, which affects the display brightness of vehicle lights. Summary of the Invention

[0003] The purpose of the embodiments of the present application is to provide a display panel, a manufacturing method of the display panel, and a taillight, so as to solve the problem of low pixel aperture ratio of the display panel. The specific technical solutions are as follows:

[0004] In a first aspect of the present application, a display panel is provided. The display panel includes: a substrate, an anode, a pixel definition layer, a light-emitting unit, a cathode, an insulating layer, and an auxiliary cathode. The anode is disposed on one side of the substrate and is arranged at intervals; the pixel definition layer is disposed on the side of the anode away from the substrate. The pixel definition layer includes a main body portion and an opening portion, and the opening portion corresponds to the anode one by one and exposes at least a part of the anode; on the side of the pixel definition layer away from the substrate, a light-emitting unit corresponding to the anode one by one and a cathode are sequentially provided, and the light-emitting unit is a red light-emitting unit; the insulating layer is located between adjacent light-emitting units, and the orthographic projection of the insulating layer on the substrate is within the orthographic projection range of the main body portion on the substrate. The height of the side of the insulating layer away from the substrate is lower than the height of the side of the cathode away from the substrate and higher than the height of the side of the cathode close to the substrate; the auxiliary cathode is disposed on the side of the insulating layer away from the substrate, and the auxiliary cathode at least partially overlaps with the cathode on the side.

[0005] In addition, the display panel provided in the first aspect of the present application may further have the following technical features:

[0006] In some embodiments, along the direction perpendicular to the substrate, the height of the auxiliary cathode is higher than the height of the cathode, and the auxiliary cathode partially overlaps with the cathode on the side.

[0007] In some embodiments, a part of the auxiliary cathode covers the surface of the cathode so that the auxiliary cathode overlaps with the cathode below.

[0008] In some embodiments, the positive projection of the auxiliary cathode on the substrate substrate is within the range of the positive projection of the insulating layer on the substrate substrate.

[0009] In some embodiments, along the direction perpendicular to the substrate substrate, the first width of the insulating layer is less than 1 mm, and the second width of the auxiliary cathode is less than 0.2 mm.

[0010] In some embodiments, the cross-section of the auxiliary cathode along the direction perpendicular to the substrate substrate is quadrilateral or irregular in shape.

[0011] In some embodiments, the edges and corners on the side of the auxiliary cathode away from the substrate substrate are rounded or chamfered.

[0012] In some embodiments, the quadrilateral includes a rectangle or a trapezoid.

[0013] In some embodiments, the cross-sectional shape of the insulating layer along the direction perpendicular to the substrate substrate is quadrilateral or irregular in structure.

[0014] In some embodiments, the display panel includes a plurality of display pixels, each of the display pixels includes at least one light-emitting unit, and the pitch between the display pixels is less than 0.2 mm.

[0015] In some embodiments, the light-emitting unit includes an electron transport layer, a first light-emitting material layer, and a hole transport layer arranged in sequence, and the hole transport layer is located on the side of the first light-emitting material layer close to the anode.

[0016] In some embodiments, the light-emitting unit further includes a second light-emitting material layer, the first light-emitting material layer and the second light-emitting material layer are located between the electron transport layer and the hole transport layer, and a charge generation layer is provided between the first light-emitting material layer and the second light-emitting material layer.

[0017] In some embodiments, the thicknesses of the first light-emitting material layer and the second light-emitting material layer are equal or unequal.

[0018] In some embodiments, the first light-emitting material layer and the second light-emitting material layer are red light-emitting materials, and Rx > 0.702.

[0019] In some embodiments, the aperture ratio of the display area of the display panel is greater than or equal to 80%, under the conditions of a temperature of 20°C - 30°C, the 2000 nit brightness life LT70 is greater than or equal to 48000 hrs, and under the conditions of a temperature of 80°C - 90°C, the 2000 nit brightness life LT70 is greater than or equal to 6500 hrs.

[0020] In some embodiments, the cathode includes a first conductive layer, and the first conductive layer is a single-element metal or an alloy; alternatively, the cathode includes a first conductive layer and a second conductive layer, the second conductive layer is disposed close to the substrate, the first conductive layer is a single-element metal or an alloy, and the second conductive layer is ytterbium metal.

[0021] In some embodiments, the light-emitting unit further includes a hole injection layer and a hole blocking layer. The hole injection layer is disposed on a side of the hole transport layer close to the anode, and the hole blocking layer is disposed on a side of the electron transport layer close to the anode. The charge generation layer includes a negative charge generation layer and a positive charge generation layer; 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 generation layer is The thickness of the positive charge generation 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 thickness of the first conductive layer is The thickness of the second conductive layer is

[0023] In some embodiments, the anode is a transparent electrode and the cathode is a reflective electrode.

[0024] The second aspect of the present application provides a method for manufacturing a display panel for manufacturing the above-mentioned display panel, including the following steps:

[0025] Provide a substrate.

[0026] Fabricate a plurality of anodes arranged at intervals on one side of the substrate.

[0027] Fabricate a pixel defining layer on a side of the anode away from the substrate, etch the pixel defining layer to form a plurality of alternately arranged body parts and opening parts, the opening parts correspond to the anodes one by one, and at least part of the anodes is exposed.

[0028] On a side of the pixel defining layer away from the substrate, deposit a light-emitting unit and a cathode in sequence under an open mask condition.

[0029] Deposit a layer of photoresist on a side of the cathode away from the substrate, and the photoresist covers the cathode.

[0030] Remove the photoresist in the first part by exposure and development, and retain the photoresist in the second part. The orthographic projection of the photoresist in the first part on the substrate is within the orthographic projection range of the body part on the substrate.

[0031] Using the photoresist in the second part as a mask, etch the cathode and the light-emitting unit to form etching holes. The etching holes extend to the surface of the body part away from the substrate, and the etching holes form intervals between adjacent light-emitting units and between adjacent cathodes.

[0032] Fill the etching holes with an insulating layer. The height of the side of the insulating layer away from the substrate is lower than the height of the side of the cathode away from the substrate and higher than the height of the side of the cathode close to the substrate.

[0033] Form an auxiliary cathode on the side of the insulating layer away from the substrate. The auxiliary cathode is at least partially located in the etching holes to overlap with the cathode side.

[0034] The third aspect of the present application provides a taillight, which includes the display panel described above.

[0035] Beneficial effects of the embodiments of the present application:

[0036] The display panel provided by the embodiments of the present application has the light-emitting unit and the cathode formed by a lithography process. Compared with the traditional vacuum evaporation process, the lithography process does not require the use of a fine metal mask. Since the manufacturing accuracy of the lithography process is significantly higher than that 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. Therefore, the pixel aperture ratio of the display panel is greatly improved. Specifically, the size of the light-emitting unit can be precisely controlled by the lithography process, so that the orthographic projection of the insulating layer used to separate adjacent light-emitting units on the substrate is within the orthographic projection range of the body part on the substrate, reducing the distance between adjacent light-emitting units and 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 the fine metal mask is cancelled, the process cost of manufacturing the display panel is significantly reduced.

[0037] The height of the side of the insulating layer away from the substrate is between the side of the cathode close to the substrate and the side away from the substrate, so that the insulating layer can completely cover the side surfaces of the light-emitting unit and the cathode, avoiding lateral current. The height difference between the insulating layer and the cathode enables the auxiliary cathode deposited on the cathode to be electrically connected to the cathode through side overlap without covering the surface of the cathode, which is beneficial to reducing the designed thickness of the auxiliary cathode and thus reducing the overall thickness of the display panel.

[0038] Of course, it is not necessary for any product or method implementing this application to achieve all of the above advantages simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of this application, and those of ordinary skill in the art can also obtain other embodiments based on these drawings.

[0040] Figure 1 Schematic structural diagram of a display panel provided by an embodiment of this application in one embodiment;

[0041] Figure 2 Schematic diagram for comparing the lifespan evaluations of display panels made by traditional technology and lithography technology at room temperature;

[0042] Figure 3 Schematic diagram for comparing the lifespan evaluations of display panels made by traditional technology and lithography technology at a high temperature of 85°C;

[0043] Figure 4 Schematic diagram for comparing the temperature rise situations of display panels made by traditional technology and lithography technology;

[0044] Figure 5a Another deformation of the display panel provided by an embodiment of this application with respect to the auxiliary cathode;

[0045] Figure 5b Another deformation of the display panel provided by an embodiment of this application with respect to the auxiliary cathode;

[0046] Figure 5c Another deformation of the display panel provided by an embodiment of this application with respect to the auxiliary cathode;

[0047] Figure 6a Another deformation of the display panel provided by an embodiment of this application with respect to the insulating layer;

[0048] Figure 6b Another deformation of the display panel provided by an embodiment of this application with respect to the insulating layer;

[0049] Figure 6c Another deformation of the display panel provided by an embodiment of this application with respect to the insulating layer;

[0050] Figure 7 Top view of the display panel provided by an embodiment of this application;

[0051] Figure 8 Stacking schematic diagram of the display panel provided by an embodiment of this application in one embodiment;

[0052] Figure 9 It is a stacked schematic diagram in another embodiment of the display panel provided by the embodiment of the present application;

[0053] Figure 10 It is a schematic diagram of the manufacturing steps of the display panel. A pixel defining layer, an anode, and a light-emitting unit are sequentially formed on the substrate;

[0054] Figure 11 It is a schematic diagram of the manufacturing steps of the display panel. A cathode is deposited on the light-emitting unit;

[0055] Figure 12 It is a schematic diagram of the manufacturing steps of the display panel. A photoresist is deposited on the cathode;

[0056] Figure 13 It is a schematic diagram of the manufacturing steps of the display panel. The light-emitting unit and the cathode are etched to form an etching hole;

[0057] Figure 14 It is a schematic diagram of the manufacturing steps of the display panel. In Figure 13 The etching hole is filled with an insulating layer;

[0058] Figure 15 It is a schematic diagram of the manufacturing steps of the display panel. An auxiliary cathode is fabricated on the insulating layer.

[0059] The reference numerals are as follows:

[0060] Substrate 100; Anode 101; Pixel defining layer 102; Body portion 102a; Light-emitting unit 103; Hole injection layer 1031; Hole transport layer 1032; First light-emitting material layer 1033; Negative charge generation layer 1034; Positive charge generation layer 1035; Second light-emitting material layer 1036; Electron transport layer 1037; Hole blocking layer 1038; Cathode 104; First conductive layer 1041; Second conductive layer 1042; Spacing 105; Insulating layer 106; First width 1061; Auxiliary cathode 107; Second width 1071; Thin film transistor 200; Photoresist 300; First part 301; Second part 302; Display pixel 400; Pitch S. Detailed implementation manners

[0061] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art based on the present application belong to the scope of protection of the present application.

[0062] The first aspect of the present application provides a display panel, such as Figure 1As shown in the figure, the display panel includes: a substrate 100, an anode 101, a pixel defining layer 102, a light-emitting unit 103, a cathode 104, an insulating layer 106, and an auxiliary cathode 107. The anode 101 is disposed on one side of the substrate 100 and arranged at intervals. The pixel defining layer 102 is disposed on the side of the anode 101 away from the substrate 100. The pixel defining layer 102 includes a main body portion 102a and an opening portion. The opening portions correspond to the anodes 101 one by one and expose at least a part of the anodes 101. On the side of the pixel defining layer 102 away from the substrate 100, a light-emitting unit 103 corresponding to the anode 101 one by one and a cathode 104 are sequentially provided. The light-emitting unit 103 is a red light-emitting unit. The insulating layer 106 is located between adjacent light-emitting units 103. The orthographic projection of the insulating layer 106 on the substrate 100 is within the orthographic projection range of the main body portion 102a on the substrate 100. The height of the side of the insulating layer 106 away from the substrate 100 is lower than the height of the side of the cathode 104 away from the substrate 100 and higher than the height of the side of the cathode 104 close to the substrate 100. The auxiliary cathode 107 is disposed on the side of the insulating layer 106 away from the substrate 100, and at least part of the side of the auxiliary cathode 107 overlaps with the cathode 104.

[0063] Among them, the display panel is a self-luminous display panel, such as an OLED (Organic Light-Emitting Diode) display panel. The display panel includes a driving circuit layer stacked on the substrate 100 for driving the display device to emit light and a display device layer for emitting light. The driving circuit layer includes a plurality of thin film transistors 200, and the display device layer includes a plurality of self-luminous light-emitting units 103.

[0064] The display device of the display panel is a plurality of independent light-emitting units 103 formed by a photolithography process and cathodes 104 corresponding to the light-emitting units 103 one by one. An auxiliary cathode 107 is provided on the upper layer of the cathode 104. The auxiliary cathode 107 is used to connect each display pixel 400 of the display panel, that is, each independent light-emitting unit 103 and the cathode 104 in series, to ensure that the circuit switch applies a voltage signal to each display pixel 400.

[0065] Specifically, the light-emitting unit 103 and the cathode 104 are formed by a lithography process. Compared with the traditional vacuum evaporation process, the lithography process does not require the use of a fine metal mask. Since the manufacturing accuracy of the lithography process is significantly higher than that 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. Therefore, the pixel aperture ratio of the display panel is greatly improved. Specifically, the size of a single light-emitting unit 103 can be precisely controlled by the lithography process, so that the orthographic projection of the insulating layer 106 used to separate adjacent light-emitting units 103 on the substrate 100 is within the orthographic projection range of the main body portion 102a on the substrate 100, reducing the distance between adjacent light-emitting units 103, increasing 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 the fine metal mask is cancelled, the process cost of manufacturing the display panel is significantly reduced.

[0066] The insulating layer 106 can be formed by an inkjet printing method. The height of the side of the insulating layer 106 away from the substrate 100 is between the side of the cathode 104 close to the substrate 100 and the side away from the substrate 100, so that the insulating layer 106 can completely cover the side surfaces of the light-emitting unit 103 and the cathode 104, avoiding lateral current. The height difference between the insulating layer 106 and the cathode 104 enables the auxiliary cathode 107 deposited on the cathode 104 to be electrically connected to the cathode 104 through side lap without covering the surface of the cathode 104, which is beneficial to reducing the designed thickness of the auxiliary cathode 107 and thus reducing the overall thickness of the display panel.

[0067] The red light-emitting unit enables the display panel to emit red light, which has a warning function. For example, it can be used as a warning light, a taillight, etc.

[0068] In some embodiments, the aperture ratio of the display area of the display panel is greater than or equal to 80%. At a temperature of 20°C - 30°C, Rx ≥ 0.702, and the 2000 nit brightness life LT70 is greater than or equal to 48000 hrs (hours). At a temperature of 80°C - 90°C, Rx ≥ 0.702, and the 2000 nit brightness life LT70 is greater than or equal to 6500 hrs. Here, nit is the intensity of light emitted per unit area of the display screen, and the unit of measurement is cd / m 2 。

[0069] When the aperture ratio of the display area increases and the current density remains unchanged, the luminance increases. When the luminance is set to the rated luminance, such as 2000 nit, at a temperature of 20°C - 30°C, Rx ≥ 0.702, and the luminance life LT70 is greater than or equal to 48000 hrs, which is a significant improvement compared to the luminance life LT70 (about 25000 hrs) of the conventional vacuum evaporation display panel. Similarly, at a temperature of 80°C - 90°C, the luminance life LT70 is also significantly improved compared to the luminance life LT70 (about 3400 hrs) of the conventional vacuum evaporation display panel.

[0070] In a specific embodiment, for a 2.78-inch deep red OLED bottom-emitting device product, the display luminance is 2000 nit, Rx = 0.702, and the aperture ratio of the display area is increased from 50% to 80%. The display luminance is increased by 60%, that is, from the original 2000 nit to 3200 nit. As Figure 2 shown in the schematic diagram of the comparison of the life curves of the conventional vacuum evaporation technology and the lithography technology of the embodiment of the present application at room temperature with a display luminance of 2000 nit. From Figure 2 this, it can be seen that the luminance life LT70 of the display panel made by the traditional technology is 25000 hrs, and the luminance life LT70 of the display panel made by the lithography technology is 50000 hrs. That is, the display panel made by the lithography technology not only improves the luminance of the display panel but also extends the service life of the display panel. LT70 is the life when the display luminance of the display panel decays to 70% of the initial display luminance.

[0071] When the pixel aperture ratio increases, in addition to improving the display luminance of the display panel, the room temperature service life and high-temperature reliability characteristics of the display panel are also significantly improved, and the product temperature rise also decreases.

[0072] Taking the red light bottom-emitting OLED structure as an example, when the product luminance is 2000 nit and the total aperture ratio of the display area is approximately 50%, the room temperature (25°C) luminance life LT70 = 25000 hrs. Through the lithography process, the total aperture ratio of the display area can be increased to 80%, and the room temperature luminance life of the display panel is increased by 200%, and the luminance life LT70 = 50000 hrs.

[0073] Similarly, still taking the red light bottom-emitting OLED structure as an example, when the product luminance is 2000 nit, Rx = 0.702, and the total aperture ratio of the display area is approximately 50%, the high-temperature (85°C) luminance life LT70 = 3400 hrs. Through the lithography process, the total aperture ratio of the display area is increased to 80%, and the luminance life LT70 = 6800 hrs, and the high-temperature luminance life is increased by 200%. The comparison results are as Figure 3 shown.

[0074] For a display panel prepared by conventional vacuum evaporation, the total aperture ratio of the display area is 50%. When the product brightness is 2000 nit, the screen current value ≈ 230 mA, and its current density ≈ 18 mA / cm 2 , after normal lighting for 1 hour, the screen temperature rises by 14°C; for a display panel prepared by lithography technology, the total aperture ratio of the display area ≈ 80%. When ensuring a display brightness of 2000 nit, the screen current value ≈ 140 mA, and its current density drops to 11 mA / cm 2 , after normal lighting for 1 hour, the screen temperature rise < 10°C. At the same time, when its current density reaches 18 mA / cm 2 , the display brightness increases by 60%, that is, 3200 nit. The comparison of its product characteristics is for reference Figure 4 .

[0075] It can be understood that along the direction perpendicular to the substrate 100, the height of the auxiliary cathode 107 can be flush with the height of the cathode 104, and the auxiliary cathode 107 and the cathode 104 are all side-lapped and electrically connected. As Figure 1 shown, the height of the auxiliary cathode 107 can be higher than the height of the cathode 104, and the auxiliary cathode 107 and the cathode 104 are partially side-lapped. The height of the auxiliary cathode 107 being higher than the height of the cathode 104 increases the thickness of the auxiliary cathode 107, reduces the probability of defects such as fracture of the auxiliary cathode 107, and is beneficial to reducing the resistance.

[0076] Optionally, as Figure 5a , Figure 5b , Figure 5c shown, when the height of the auxiliary cathode 107 is higher than the height of the cathode 104, a part of the auxiliary cathode 107 covers the surface of the cathode 104 so that the auxiliary cathode 107 and the cathode 104 are bottom-lapped. The auxiliary cathode 107 and the cathode 104 are partially side-lapped and partially bottom-lapped, increasing the contact area between the auxiliary cathode 107 and the cathode 104, reducing the contact resistance, and at the same time improving the connection stability.

[0077] As Figure 1 , Figure 5a and Figure 5b shown, the orthographic projection of the auxiliary cathode 107 on the substrate 100 is within the orthographic projection range of the insulating layer 106 on the substrate 100. That is, the size of the auxiliary cathode 107 does not exceed the size of the insulating layer 106. By reducing the size of the auxiliary cathode 107, the occupation of the effective area where the light-emitting unit 103 can be arranged is reduced, and the pixel aperture ratio of the display panel is improved.

[0078] Optionally, as Figure 1 , Figure 5a and Figure 5bAs shown, along the direction perpendicular to the substrate 100, the first width 1061 of the insulating layer 106 is less than 1 mm. For example, the first width 1061 of the insulating layer 106 can be 0.95 mm, 0.9 mm, 0.85 mm, 0.8 mm, etc. The second width 1071 of the auxiliary cathode 107 is less than 0.2 mm. For example, the second width 1071 of the auxiliary cathode 107 can be 0.18 mm, 0.16 mm, 0.15 mm, etc. The size of the auxiliary cathode 107 needs to comprehensively consider factors such as electrical connection stability and manufacturing difficulty.

[0079] In some embodiments, the cross-section of the auxiliary cathode 107 along the direction perpendicular to the substrate 100 is a quadrilateral or a special-shaped structure. Among them, the quadrilateral can be, for example, a rectangle, a trapezoid, or a parallelogram. The trapezoid can be a regular trapezoid or an inverted trapezoid. A regular trapezoid means that the upper base size is smaller than the lower base size, and an inverted trapezoid is the opposite, where the lower base size is smaller than the upper base size. As Figure 1 shown, the cross-section of the auxiliary cathode 107 along the direction perpendicular to the substrate 100 is a rectangle. The special-shaped structure is, for example, a "T" shape, that is, the auxiliary cathode 107 includes not only the part located between adjacent light-emitting units 103 but also the part covering the surface of the cathode 104. The "T" shape mentioned in this application is not a strict "T" shape but a distribution close to a "T" shape. As Figure 5a 、 Figure 5b and Figure 5c shown, the auxiliary cathode 107 is in a special-shaped structure in each case.

[0080] Optionally, the edges and corners of the auxiliary cathode 107 on the side away from the substrate 100 are rounded or chamfered. As Figure 5b shown, the edges and corners of the auxiliary cathode 107 on the side away from the substrate 100 are rounded. By rounding or chamfering the side of the auxiliary cathode 107 away from the substrate 100, the climbing difficulty during the subsequent film deposition process can be reduced, the risk of climbing fracture of the subsequent film at the edges and corners can be reduced, and the yield of the display panel can be improved.

[0081] Similarly, the cross-sectional shape of the insulating layer 106 along the direction perpendicular to the substrate 100 can also be a quadrilateral or a special-shaped structure. Among them, the quadrilateral can be, for example, a rectangle, a trapezoid, or a parallelogram. The trapezoid can be a regular trapezoid or an inverted trapezoid. As Figure 6a shown, the cross-sectional shape of the insulating layer 106 along the direction perpendicular to the substrate 100 is a rectangle. As Figure 1 shown, the cross-sectional shape of the insulating layer 106 along the direction perpendicular to the substrate 100 is a regular trapezoid. As Figure 6cThe cross-sectional shape of the insulating layer 106 along the direction perpendicular to the substrate 100 is an inverted trapezoid. The special shape is, for example, a "T" shape, that is, the auxiliary cathode 107 includes not only the part located between adjacent light-emitting units 103, but also the part covering the surface of the light-emitting unit 103. The "T" shape mentioned in this application is not a strict "T" shape, but a distribution close to the "T" shape.

[0082] Moreover, the edges and corners of the insulating layer 106 on the side far from the substrate 100 are also rounded or chamfered. As Figure 6c shown, the edges and corners of the insulating layer 106 on the side far from the substrate 100 are rounded. By rounding or chamfering the side of the insulating layer 106 far from the substrate 100, the climbing difficulty of the auxiliary cathode 107 during deposition can be reduced, the risk of climbing fracture of the auxiliary cathode 107 at the edges and corners can be reduced, and the yield of the display panel can be improved.

[0083] As Figure 7 shown, the display panel includes a plurality of display pixels 400, each display pixel 400 includes at least one light-emitting unit 103, and the pitch S between the display pixels 400 is less than 0.2 mm, for example, it can be 0.19 mm, 0.18 mm, 0.17 mm, 0.16 mm, 0.15 mm, etc. The smaller the pitch S, the more display pixels 400 can be set per unit area, which is beneficial to improving the brightness of the display panel. The pitch S between the display pixels 400 of the display panel made by conventional vacuum evaporation is about 1.0 mm. The photolithography technology for preparing the light-emitting unit 103 and the cathode 104 significantly reduces the pitch S between the display pixels 400.

[0084] For a monochromatic display panel, one light-emitting unit 103 is one display pixel 400. Therefore, the pitch S between the display pixels 400 is the distance between the light-emitting units 103.

[0085] In some embodiments, as Figure 1 、 Figures 5a - 5c 、 Figures 6a - 6c shown, the light-emitting unit 103 includes an electron transport layer (ETL) 1037, a first emitting layer (EML) 1033, and a hole transport layer (HTL) 1032 arranged in sequence, and the hole transport layer 1032 is located on the side close to the anode 101.

[0086] Since the electron transport layer 1037, the first light-emitting material layer 1033, and the hole transport layer 1032 are arranged in sequence, the hole transport layer 1032 is arranged close to the anode 101 side, while the electron transport layer 1037 is arranged close to the cathode 104 side. When a current is applied, electrons are injected into the cathode 104, and holes are formed at the anode 101. The electrons and holes will move towards each other through each layer, and finally meet and combine in the light-emitting layer, releasing energy in the form of photons. This process will occur rapidly and continuously when the current passes, thus causing continuous light emission.

[0087] In some embodiments, as Figure 8 shown, the light-emitting unit 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 located between the electron transport layer 1037 and the hole transport layer 1032, and a charge generation layer (Charge Generation Layer, CGL) is provided between the first light-emitting material layer 1033 and the second light-emitting material layer 1036. Specifically, the charge generation layer includes a positive charge generation layer (Positive Charge Generation Layer, PCGL) 1035 and a negative charge generation layer (Negative Charge Generation Layer, NCGL) 1034.

[0088] In this embodiment, the light-emitting unit 103 includes two light-emitting materials, which are used to improve the light-emitting brightness of the display panel. For the rated light-emitting brightness, by setting two light-emitting materials, the light-emitting brightness of each light-emitting material can be reduced, so that each light-emitting material emits light under the condition of being lower than the limit brightness, achieving the purpose of extending the service life of the light-emitting material.

[0089] Among them, the thicknesses of the first light-emitting material layer 1033 and the second light-emitting material layer 1036 can be equal. The equal thicknesses of the two light-emitting materials make the light-emitting brightnesses of the two light-emitting materials consistent, and the two light-emitting materials can be adjusted to the optimal light-emitting brightness by designing the thickness.

[0090] Of course, the thicknesses of the first light-emitting material layer 1033 and the second light-emitting material layer 1036 can also be unequal. If the thicknesses of the two light-emitting materials are unequal, one layer can be set as the main light-emitting layer and the other layer can be set as the auxiliary light-emitting layer, so as to achieve the purpose of improving the brightness of the display panel.

[0091] Optionally, the first light-emitting material layer 1033 and the second light-emitting material layer 1036 are red light-emitting materials, and the color coordinate Rx > 0.702.

[0092] The color coordinates Rx of the first light-emitting material layer 1033 and the second light-emitting material layer 1036 are greater than 0.702, so that the light-emitting color of the display panel is dark red, improving the warning effect. At the same time, as the color deepens, the wavelength also becomes longer and is not easily scattered during propagation. Therefore, the penetration ability of the light of the emitted color can also be improved. When the display panel is used as a display component of a car tail light, the dark red light emitted by the display panel has a longer propagation distance and better plays the role of safety warning.

[0093] As a specific embodiment, the color coordinate Rx can be 0.708.

[0094] In some embodiments, such as Figure 8 shown, the anode 101 is a transparent electrode, which can be made of conductive materials such as indium tin oxide (ITO) and indium zinc oxide (IZO); the cathode 104 is an opaque electrode.

[0095] In this embodiment, the cathode 104 serves as a reflective electrode, and the anode 101 serves as the light-emitting side, that is, the display panel is a bottom-emitting display panel. Compared with the top-emitting display panel, the structure of the bottom-emitting display panel can be simpler.

[0096] Such as Figure 8 shown, the cathode 104 includes a first conductive layer 1041, and the first conductive layer 1041 is a single metal or an alloy; alternatively, the cathode 104 includes a first conductive layer 1041 and a second conductive layer 1042, the second conductive layer 1042 is disposed close to the substrate 100, the first conductive layer 1041 is a single metal or an alloy, and the second conductive layer 1042 is ytterbium metal.

[0097] The cathode 104 can be composed of only one conductive layer or two conductive layers. When there is only one conductive layer, the conductive layer can be a single metal such as aluminum, copper, gold, silver, etc., or an alloy such as a magnesium-silver alloy, an aluminum alloy, a copper alloy, etc. When composed of two conductive layers, the second conductive layer 1042 disposed close to the substrate 100 is ytterbium metal, and the first conductive layer 1041 disposed far from the substrate 100 is a single metal or an alloy. Specifically, the single metal is such as aluminum, copper, gold, silver, etc., and can also be an alloy such as a magnesium-silver alloy, an aluminum alloy, a copper alloy, etc.

[0098] Of course, such as Figure 8As shown, the light-emitting unit 103 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 closer to the anode 101, and the hole blocking layer 1038 is disposed on the side of the electron transport layer 1037 closer to the anode 101. 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 generation 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 first conductive layer 1041 is The thickness of the second conductive layer 1042 is

[0099] 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 disposed between the second light-emitting material layer 1036 and the electron transport layer 1037, which can significantly improve the electron collection rate at the interface, and its hole blocking ability will also increase with the increase of its thickness. In addition, since the thickness of the hole blocking layer 1038 is relatively thin, such as etc., under the action of an electric field, holes can also tunnel through the relatively thin hole blocking layer 1038. Therefore, it can not only improve the electron transport rate but also extend the service life of the OLED device, and it is an indispensable product for the OLED device.

[0100] The cathode 104 is composed of two conductive layers. The first conductive layer 1041 has a relatively thin thickness, such as it can be etc., and the second conductive layer 1042 has a relatively thick thickness, such as it can be etc. The main function of the first conductive layer is to increase the electron injection rate.

[0101] In this embodiment, the thickness range of the first light-emitting material layer 1033 and the second light-emitting material layer 1036 is The thicknesses of the two light-emitting materials can be equal or unequal. When the bottom-emitting device includes only one light-emitting material layer, its structure can be further simplified, such as Figure 9As shown, the bottom-emitting vehicle taillight device with a monochromatic design has a simple structure and is composed of only 7 stacked film layers, namely a hole injection layer 1031 with a thickness of , a hole transport layer 1032 with a thickness of , a red emitting layer (REML) with a thickness of , a hole blocking layer 1038 with a thickness of , an electron transport layer (ETL) 1037 with a thickness of , a first conductive layer ytterbium (Yb) 1041 with a thickness of , and a cathode (CTD) 104 with a thickness of . Among them, the manufacturing material of the ETL can be 8-Hydroxyquinolinolato-lithium (Liq).

[0102] In the second aspect of the embodiments of the present application, a manufacturing method of a display panel is provided for manufacturing the above-mentioned display panel, including the following steps:

[0103] S100: Provide a substrate 100.

[0104] S200: Fabricate a plurality of anodes 101 arranged at intervals on one side of the substrate 100.

[0105] S300: Fabricate a pixel defining layer 102 on the side of the anode 101 away from the substrate 100, etch the pixel defining layer 102 to form a plurality of alternately arranged main body parts 102a and openings, the openings correspond to the anodes 101 one by one, and at least part of the anodes 101 is exposed.

[0106] S400: On the side of the pixel defining layer 102 away from the substrate 100, deposit a layer of light-emitting unit 103 under an open mask condition, as Figure 10 shown.

[0107] S500: On the side of the light-emitting unit 103 away from the substrate 100, deposit a layer of cathode 104 under an open mask condition, as Figure 11 shown.

[0108] S600: Deposit a layer of photoresist 300 on the side of the cathode 104 away from the substrate 100, and the photoresist 300 covers the cathode 104, as Figure 12 shown.

[0109] S700: Remove the photoresist 300 of the first part 301 through exposure and development, and retain the photoresist 300 of the second part 302. The orthographic projection of the photoresist 300 of the first part 301 on the substrate 100 is within the orthographic projection range of the body part 102a on the substrate 100, as Figure 12 shown.

[0110] S800: Using the photoresist 300 of the second part 302 as a mask, etch the cathode 104 and the light-emitting unit 103 to form etching holes. The etching holes extend to the surface of the body part 102a away from the substrate 100. The etching holes form the intervals 105 between adjacent light-emitting units 103 and between adjacent cathodes 104, as Figure 13 shown.

[0111] S900: Fill the insulating layer 106 in the etching holes. The height of the side of the insulating layer 106 away from the substrate 100 is lower than the height of the side of the cathode 104 away from the substrate 100, and higher than the height of the side of the cathode 104 close to the substrate 100, as Figure 14 shown.

[0112] S1000: Form an auxiliary cathode 107 on the side of the insulating layer 106 away from the substrate 100. The auxiliary cathode 107 is at least partially located in the etching holes to overlap with the side of the cathode 104, as Figure 15 shown.

[0113] In this embodiment, the driving layer of the thin-film transistor 200 of the display panel is prepared by using a common lithography process, which will not be elaborated here. The light-emitting unit 103 and the cathode 104 are deposited in a whole layer under an open mask condition, and then the light-emitting unit 103 and the cathode 104 arranged in a whole layer are etched into individual light-emitting units 103 and cathodes 104 arranged at intervals by using a lithography process. The open mask replaces the fine metal mask, significantly reducing the manufacturing cost of the display panel. And due to the high etching precision of the lithography process, the width of the interval 105 between adjacent light-emitting units 103 and cathodes 104 is smaller than the width of the body part 102a of the pixel defining layer 102, greatly improving the pixel aperture ratio of the display panel, thereby improving the brightness of the display panel.

[0114] In the third aspect of the present application, a taillight is provided. The taillight includes the above-mentioned display panel. Since the light-emitting unit 103 and the cathode 104 of the display panel of the taillight are prepared by using a lithography process, compared with the traditional vacuum evaporation process, the use of the fine metal mask plate is omitted, significantly reducing the manufacturing cost of the display panel. And due to the high etching precision of the lithography process, the pixel aperture ratio of the display panel is greatly improved, thereby improving the display brightness of the display panel, which can extend the service life of the device and enhance the user experience.

[0115] It should be noted that in this text, relational terms such as first and second are only used 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 term "comprising", "including" or any other variant thereof is 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 expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the said element.

[0116] Each embodiment in this specification is described in a related manner. For the same or similar parts among the embodiments, reference can be made to each other, and the differences between each embodiment and other embodiments are emphasized.

[0117] The above description is only a preferred embodiment of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application are included in the protection scope of the present application.

Claims

1. A display panel, characterized in that, the display panel comprises: a substrate; anodes, disposed on one side of the substrate and arranged at intervals; a pixel defining layer, the pixel defining layer is disposed on the side of the anode away from the substrate, the pixel defining layer includes a body portion and an opening portion, the opening portion corresponds to the anode one by one, and at least part of the anode is exposed; a light-emitting unit corresponding to the anode one by one and a cathode are sequentially disposed on the side of the pixel defining layer away from the substrate, and the light-emitting unit is a red light-emitting unit; an insulating layer, the insulating layer is located between adjacent light-emitting units, a positive projection of the insulating layer on the substrate is within a positive projection range of the body portion on the substrate, a height of a side of the insulating layer away from the substrate is lower than a height of a side of the cathode away from the substrate, and is higher than a height of a side of the cathode close to the substrate; an auxiliary cathode, the auxiliary cathode is disposed on the side of the insulating layer away from the substrate, and at least part of the auxiliary cathode is side-lapped with the cathode.

2. The display panel according to claim 1, characterized in that, along a direction perpendicular to the substrate, a height of the auxiliary cathode is higher than a height of the cathode, and at least part of the auxiliary cathode is side-lapped with the cathode.

3. The display panel according to claim 2, characterized in that, a part of the auxiliary cathode covers a surface of the cathode so that the auxiliary cathode is under-lapped with the cathode.

4. The display panel according to claim 1, characterized in that, a positive projection of the auxiliary cathode on the substrate is within a positive projection range of the insulating layer on the substrate.

5. The display panel according to claim 4, characterized in that, along a direction perpendicular to the substrate, a first width of the insulating layer is less than 1 mm, and a second width of the auxiliary cathode is less than 0.2 mm.

6. The display panel according to claim 1, characterized in that, a cross-section of the auxiliary cathode along a direction perpendicular to the substrate is a quadrilateral or a special-shaped structure.

7. The display panel according to claim 6, characterized in that, edges and corners of the auxiliary cathode along the side away from the substrate are rounded or chamfered.

8. The display panel according to claim 6, characterized in that, the quadrilateral includes a rectangle or a trapezoid.

9. The display panel according to any one of claims 1-8, characterized in that, a cross-section shape of the insulating layer along a direction perpendicular to the substrate is a quadrilateral or a special-shaped structure.

10. The display panel according to any one of claims 1-8, characterized in that, the display panel includes a plurality of display pixels, each display pixel includes at least one light-emitting unit, and a pitch between the display pixels is less than 0.2 mm.

11. The display panel according to any one of claims 1-8, characterized in that, The light-emitting unit includes an electron transport layer, a first light-emitting material layer, and a hole transport layer arranged in sequence, and the hole transport layer is located on the side of the first light-emitting material layer close to the anode.

12. The display panel according to claim 11, wherein, the light-emitting unit further includes a second light-emitting material layer, the first light-emitting material layer and the second light-emitting material layer are located between the electron transport layer and the hole transport layer, and a charge generation layer is provided between the first light-emitting material layer and the second light-emitting material layer.

13. The display panel according to claim 12, wherein, the thicknesses of the first light-emitting material layer and the second light-emitting material layer are equal or unequal.

14. The display panel according to claim 12, wherein, the first light-emitting material layer and the second light-emitting material layer are red light-emitting materials, and Rx > 0.

702.

15. The display panel according to claim 14, wherein, the aperture ratio of the display area of the display panel is greater than or equal to 80%, the 2000 nit brightness life LT70 is greater than or equal to 48000 hrs under the condition of a temperature of 20°C - 30°C, and the 2000 nit brightness life LT70 is greater than or equal to 6500 hrs under the condition of a temperature of 80°C - 90°C.

16. The display panel according to claim 12, wherein, the cathode includes a first conductive layer, and the first conductive layer is a single metal or an alloy; or, the cathode includes a first conductive layer and a second conductive layer, the second conductive layer is arranged close to the substrate, the first conductive layer is a single metal or an alloy, and the second conductive layer is ytterbium metal.

17. The display panel according to claim 16, wherein, the light-emitting unit further includes a hole injection layer and a hole blocking layer, the hole injection layer is arranged on the side of the hole transport layer close to the anode, the hole blocking layer is arranged on the side of the electron transport layer close to the anode, and the charge generation layer includes a negative charge generation layer and a positive charge generation layer; 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 generation layer is The thickness of the positive charge generation 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 thickness of the first conductive layer is The thickness of the second conductive layer is 18. The display panel according to any one of claims 1 - 8, wherein, the anode is a transparent electrode and the cathode is a reflective electrode.

19. A manufacturing method of a display panel for manufacturing the display panel according to any one of claims 1 - 18, wherein, it includes the following steps: providing a substrate; fabricating a plurality of anodes arranged at intervals on one side of the substrate; fabricating a pixel definition layer on the side of the anode away from the substrate, etching the pixel definition layer to form a plurality of alternately arranged main body parts and opening parts, the opening parts correspond to the anodes one by one and expose at least part of the anodes; on the side of the pixel definition layer away from the substrate, sequentially depositing a light-emitting unit and a cathode under an open mask condition; depositing a layer of photoresist on the side of the cathode away from the substrate, and the photoresist covers the cathode; Remove the photoresist in the first part by exposure and development, and retain the photoresist in the second part. The orthographic projection of the photoresist in the first part on the substrate is within the orthographic projection range of the body part on the substrate. Using the photoresist in the second part as a mask, etch the cathode and the light-emitting unit to form etching holes. The etching holes extend to the surface of the body part away from the substrate, and the etching holes form intervals between adjacent light-emitting units and between adjacent cathodes. Fill the etching holes with an insulating layer. The height of the side of the insulating layer away from the substrate is lower than the height of the side of the cathode away from the substrate and higher than the height of the side of the cathode close to the substrate. Form an auxiliary cathode on the side of the insulating layer away from the substrate. The auxiliary cathode is at least partially located in the etching hole to overlap with the cathode side.

20. A taillight Characterized in that The taillight includes the display panel according to any one of claims 1-18.

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