Display substrate and display panel

Abstract

The application provides a display substrate and a display panel. The display substrate comprises a substrate, a pixel definition layer, a plurality of light emitting devices and an expansion layer. The pixel definition layer is located on the substrate and comprises a plurality of openings. The plurality of light emitting devices are defined in the openings, and part of the plurality of light emitting devices are color deviation light emitting devices. The expansion layer is located on the side of the pixel definition layer away from the substrate, and at least part of the expansion layer surrounds the opening in which the color deviation light emitting device is defined. At high temperature, the expansion layer expands to shield the light emitted by the color deviation light emitting device, thereby reducing the light emitting brightness of the sub-pixel corresponding to the color deviation light emitting device, so as to alleviate or eliminate the high-temperature color deviation problem of the display substrate and the display panel.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a display substrate and a display panel having the same. BACKGROUND

[0002] An organic light-emitting diode (OLED) has the advantages of simple preparation process, low cost, small power consumption, high brightness, wide viewing angle, high contrast and flexible display, and is widely used in various electronic display products.

[0003] However, the electronic display product using the organic light-emitting diode technology has high temperature dependence. At the same driving voltage, the brightness of the organic light-emitting diode changes with temperature. Therefore, when the ambient temperature changes, the OLED display will produce color cast, so that the display image of the electronic display product is distorted, and the user experience is reduced. SUMMARY

[0004] In a first aspect, the present application provides a display substrate, which includes a substrate, a pixel definition layer, an expansion layer and a plurality of light-emitting devices. The pixel definition layer is located on the substrate and includes a plurality of openings. The light-emitting devices are defined in the openings, and part of the plurality of light-emitting devices are color cast light-emitting devices. The expansion layer is located on the side of the pixel definition layer away from the substrate. At least part of the expansion layer surrounds the opening defining the color cast light-emitting device.

[0005] When the ambient temperature of the display substrate increases, the expansion layer will block part of the light emitted by the color cast light-emitting device, thereby reducing the brightness of the sub-pixel corresponding to the color cast light-emitting device, to improve the color cast phenomenon of the display substrate.

[0006] In combination with the first aspect, in some embodiments, the shape of the orthographic projection of the part of the expansion layer surrounding the opening on the substrate is a straight line segment; in other embodiments, the shape of the orthographic projection of the part of the expansion layer surrounding the opening on the substrate is a non-closed ring; in other embodiments, the shape of the orthographic projection of the part of the expansion layer surrounding the opening on the substrate is a closed ring.

[0007] In the above scheme, there are multiple technical solutions for the expansion layer to at least partially surround the opening defining the color cast light-emitting device, and the advantages of the multiple solutions are that, while improving the color cast phenomenon of the display substrate by reducing the brightness of the sub-pixel corresponding to the color cast light-emitting device, the setting scheme of the expansion layer relative to the color cast light-emitting device can also be designed according to the specific color cast situation of the display substrate, thereby improving the applicability of the method.

[0008] In some embodiments of the first aspect, the expansion layer is arranged only at the periphery of the opening defined by the color-distorted light-emitting device.

[0009] In the above solution, according to the specific color distortion of the display substrate, the luminance of the sub-pixel corresponding to the color-distorted light-emitting device is reduced to be the same or similar to the luminance of the sub-pixel corresponding to other light-emitting devices, so as to finally achieve the purpose of improving the color distortion of the display substrate.

[0010] In some other embodiments of the first aspect, the expansion layer is arranged at the periphery of each opening, and the expansion coefficient of the expansion layer surrounding part of the color-distorted light-emitting device is greater than the expansion coefficient of the expansion layer surrounding other parts of other light-emitting devices.

[0011] In the above solution, according to the specific situation that the luminous quantity of each light-emitting device changes with temperature, the luminance of the sub-pixel corresponding to each light-emitting device is changed by the different degrees of expansion of the different expansion layers on each light-emitting device, so that the luminance of the sub-pixel corresponding to different light-emitting devices is the same or similar, thereby effectively improving the color distortion of the display substrate.

[0012] In some embodiments of the first aspect, the expansion layer is composed by doping a thermal expansion material in the main film layer, and the greater the doping concentration, the greater the expansion volume of the expansion layer. Further, the main film layer and the pixel defining layer are integrally formed.

[0013] In the above solution, by adjusting the parameters of the expansion layer, such as the doping concentration of the expansion material or the type of the expansion material, the expansion coefficient of the expansion layer is adjusted, so that the luminance of the light-emitting device corresponding to the sub-pixel can be adjusted, and the color distortion of the display substrate can be accurately improved. In addition, when the main film layer and the pixel defining layer are integrally formed, there is no physical interface between the expansion layer and the pixel defining layer, which avoids the problem of interface separation between the expansion layer and the pixel defining layer, improves the stability of the film group structure of the entire display substrate, and further improves the service life of the display substrate.

[0014] In some embodiments of the first aspect, the expansion layer has a guide structure on the end surface away from the color-distorted pixel defining layer, and the guide structure is configured to increase the surface area of the end surface of the expansion layer away from the substrate.

[0015] In the above solution, by arranging the guide structure, the surface of the expansion layer away from the pixel defining layer is more easily expanded during the expansion process, the expansion speed of the expansion layer is improved, and the luminance of the sub-pixel corresponding to the light-emitting device is more effectively changed, thereby efficiently improving the high-temperature color distortion of the display substrate.

[0016] In conjunction with the first aspect, in some embodiments, the guide structure consists of multiple protrusions, for example, further, the protrusions are linear protrusions, and the extending direction of the linear protrusions is substantially parallel to the edge of the corresponding opening.

[0017] In conjunction with the first aspect, in other embodiments, the guide structure is a plurality of grooves. For example, further, the grooves are linear grooves, and the plurality of linear grooves intersect each other to form a cross shape and / or a grid shape.

[0018] In conjunction with the first aspect, in some embodiments, the inflated layer is semi-transparent. For example, further, the transparency of the inflated layer is 30%-50%.

[0019] In the above scheme, by setting the expansion layer to a semi-transparent state, the light emission brightness of the sub-pixel corresponding to the light-emitting device at this position can be adjusted without changing the aperture ratio of the sub-pixel, thereby improving the display effect of the display image on the display substrate.

[0020] In conjunction with the first aspect, in some other embodiments, the expansion layer is a light-shielding material.

[0021] In the above scheme, by setting the expansion layer as a light-shielding material, the aperture ratio of the sub-pixel corresponding to the light-emitting device at this position can be adjusted to improve the color shift phenomenon of the display substrate.

[0022] In conjunction with the first aspect, in some embodiments, the display substrate further includes a cathode fabricated using a malleable electrode material, and the cathode covers the pixel defining layer and the opening. For example, the malleable electrode material further includes any one of silver, metal nanowires, carbon nanotubes, and graphene.

[0023] In the above scheme, by limiting the cathode preparation material, the risk of the cathode breaking due to the expansion of the expansion layer is reduced, and the service life of the display substrate is improved.

[0024] In conjunction with the first aspect, in some embodiments, the edge of the orthographic projection of the cathode onto the surface of the substrate is curved. For example, further, the curve is sawtooth-shaped or wavy.

[0025] In the above scheme, by designing the shape of the cathode, the cathode can release outward stress when the expansion layer contracts, making the cathode less prone to damage and thus improving the service life of the cathode. In addition, this scheme can make the cathode not limited to being designed as a malleable electrode, thereby increasing the range of cathode material types to reduce costs.

[0026] A second aspect of this application provides a display panel. The display panel includes any of the display substrates provided in the first aspect described above. Attached Figure Description

[0027] Figure 1 FIG. 1 is a structural schematic diagram of a display substrate according to an embodiment of the present application.

[0028] Figure 2 FIG. 2 is a schematic partial cross-sectional view of the display substrate shown in FIG. 1. Figure 1

[0029] Figure 3 FIG. 3 is a diagram of the change in the state of the expansion layer relative to the relative pixel defining layer during the process of the temperature rising.

[0030] Figure 4 FIG. 4 is a schematic diagram of the orthographic projection of the cathode on the plane of the substrate.

[0031] Figure 5 FIG. 5 is a structural schematic diagram of a partial area of a display substrate according to an embodiment of the present application.

[0032] Figure 6 FIG. 6 is a structural schematic diagram of a partial area of another display substrate according to an embodiment of the present application.

[0033] Figure 7 FIG. 7 is a structural schematic diagram of a partial area of another display substrate according to an embodiment of the present application.

[0034] Figure 8 FIG. 8 is a structural schematic diagram of a partial area of another display substrate according to an embodiment of the present application.

[0035] Figure 9 FIG. 9 is a schematic partial cross-sectional view of the display substrate shown in FIG. 8. Figure 8

[0036] Figure 10 FIG. 10 is a structural schematic diagram of a display substrate according to an embodiment of the present application.

[0037] Figure 11 FIG. 11 is a schematic partial cross-sectional view of the display substrate shown in FIG. 10. Figure 10

[0038] FIG. 12 is a structural schematic diagram of a display substrate according to an embodiment of the present application. Figure 12

[0039] FIG. 13 is a schematic partial cross-sectional view of the display substrate shown in FIG. 12. Figure 13 Figure 12 FIG. 14 is a structural schematic diagram of a display substrate according to an embodiment of the present application.

[0040] Figure 14 FIG. 15 is a schematic partial cross-sectional view of the display substrate shown in FIG. 14.

[0041] Figure 15 FIG. 16 is a structural schematic diagram of a display substrate according to an embodiment of the present application. Figure 14 ​​​​

[0042] Figure 16 is a top view of the expansion layer with a guide structure.

[0043] Figure 17 is Figure 16 is a cross-sectional view along M1-N1 of the pattern shown.

[0044] Figure 18 is a top view of the expansion layer with a guide structure.

[0045] Figure 19 is Figure 18 is a cross-sectional view along M2-N2 of the pattern shown. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0047] The display area of the display substrate is distributed with a plurality of pixels (may be referred to as large pixels), which can emit light of different colors and different brightnesses. Each pixel includes a plurality of sub-pixels (may be referred to as sub-pixels), each sub-pixel emits light of a specific color, and the light emission brightness of each sub-pixel can be adjusted. By adjusting the light emission brightness of different sub-pixels to combine different light emission colors and light emission brightness of the pixel, the main structure of the light emission of the sub-pixel can be realized as an OLED device. The OLED device has high dependence on temperature. With the change of the ambient temperature, the mobility of different organic materials in OLED devices with different light emission colors changes differently. Therefore, under the same driving voltage, with the change of temperature, the brightness of different OLED devices changes differently, so that the light emission brightness of the sub-pixel is different from the preset light emission brightness, thereby causing the light emission brightness and the light emission color of the sub-pixel to deviate, and further causing the display of the display substrate to deviate in color. Further, under long-time high-temperature operation, due to the difference in temperature sensitivity of OLED devices with different light emission colors in the display substrate, the display substrate will produce irreversible color deviation.

[0048] The light emitting brightness of different types (e.g. different light emitting colors) of OLED devices in a display substrate can all be affected by high temperature, but the color cast of the display substrate tends to be towards the light emitting color of one type of OLED device or a combination of the light emitting colors of several types (not all types) of OLED devices, i.e. the color cast of the display substrate can be considered to be mainly caused by one or several OLED devices, which can be referred to as color cast light emitting devices. Thus, the color cast light emitting devices refer to the light emitting devices in the display substrate that are most sensitive to temperature. Specifically, under the same driving voltage, the mobility of the organic material in the color cast light emitting devices changes more greatly with temperature than other light emitting devices, which makes the brightness of the color cast light emitting devices increase with the increase of temperature, while the brightness of other light emitting devices does not change or changes relatively less than the color cast light emitting devices, which makes the light emitted by the color cast light emitting devices brighter than the light emitted by other light emitting devices, and thus causes the color cast of the display substrate.

[0049] Taking a display substrate including OLED devices emitting R (red), G (green) and B (blue) color light as an example, the decay amplitude of the light emitting efficiency of the red light emitting devices is less than that of the green light emitting devices, and the decay amplitude of the light emitting efficiency of the green light emitting devices is less than that of the blue light emitting devices. Therefore, it can be known that in a high temperature environment, the color cast of some display substrates is towards the red color, and thus the red light emitting devices are color cast light emitting devices; if the display substrate is used to display a picture, the picture may appear yellow cast, and thus the red light emitting devices and the green light emitting devices are color cast light emitting devices.

[0050] Embodiments of the present application provide a display substrate, which can improve the color cast of the display substrate in a high temperature environment. The display substrate includes a substrate, a pixel defining layer, a plurality of light emitting devices and an expansion layer. The pixel defining layer is located on the substrate and includes a plurality of openings. The plurality of light emitting devices are defined in the openings, and part of the plurality of light emitting devices are color cast light emitting devices. The expansion layer is located on the side of the pixel defining layer away from the substrate, and at least part of the expansion layer surrounds the opening defining the color cast light emitting devices. In the display substrate, as the ambient temperature increases, the expansion layer located on the side of the pixel defining layer away from the substrate expands, and as the volume of the expansion layer increases, it gradually extends towards the opening defining the color cast light emitting devices, thereby shielding part of the light emitted by the color cast light emitting devices, i.e. reducing the brightness of the sub-pixel corresponding to the color cast light emitting devices, thereby improving the color cast of the display substrate.

[0051] The embodiments of the present application will be described below in conjunction with the drawings. It should be understood that the implementation of the present application can be varied and is not to be limited to the embodiments set forth herein, which are meant to be exemplary only.

[0052] In at least one embodiment of the present application, as shown in Figure 1 , Figure 2 and Figure 3 , the display substrate includes a base 11, and a pixel defining layer 12, a plurality of light emitting devices 13a (red light emitting device), 13b (green light emitting device), 13c (blue light emitting device), and an expansion layer 14a on the base 11. The pixel defining layer 12 includes a plurality of openings (which can also be understood as grooves). The light emitting devices 13a, 13b, 13c are defined in the openings, and it is assumed that the red light emitting device 13a is a color-biased light emitting device. The expansion layer 14a is located on the side of the pixel defining layer 12 away from the base 11, and at least part of the expansion layer 14a surrounds the opening in which the red light emitting device 13a is defined. As the temperature rises, the expansion layer 14a expands to block part of the light emitted by the red light emitting device 13a, thereby improving the color-biased phenomenon of the display substrate. As shown in Figure 3 , when the expansion layer 14a is not expanded, the width of the expansion layer 14a and the width of the part of the pixel defining layer 12 between adjacent light emitting devices are approximately equal, so that the light emitted by the red light emitting device 14a is not blocked. At high temperatures, the expansion layer 14a expands to become an expansion layer 14d, and the width of the expansion layer 14d is greater than the width of the part of the pixel defining layer 12 between adjacent light emitting devices, i.e., the expansion layer 14d extends to the periphery to block at least part of the opening, thereby blocking part of the light emitted by the red light emitting device 13a, and thereby improving the color-biased phenomenon of the display substrate.

[0053] In an embodiment of the present application, the base can be an array substrate including a substrate and a drive circuit layer, which can include a pixel drive circuit. In each sub-pixel corresponding to a light emitting device, the pixel drive circuit can include a plurality of transistors, capacitors, etc., such as 2T1C (i.e., 2 transistors (T) and 1 capacitor (C)), 3T1C, or 7T1C, etc. The pixel drive circuit is connected to the light emitting device to control the switching state and luminance of the light emitting device.

[0054] In embodiments of the present application, the light emitting device can include an anode, a cathode, and a light emitting functional layer located between the anode and the cathode, the light emitting functional layer including a light emitting layer, the light emitting layer being located in the opening of the pixel defining layer. Generally, to ensure the alignment of the anode and the opening of the pixel defining layer, the anode is located between the pixel defining layer and the substrate, and the size (e.g. area) of the anode is larger than the size (e.g. area) of the corresponding opening. The cathode of each light emitting device is generally shared, and thus the cathode is located on the side of the pixel defining layer facing away from the substrate and covers the pixel defining layer and the opening.

[0055] It should be understood that in embodiments of the present application, the light emitting device is not limited to the three types in the above examples, and the color of the light emitting device is also not limited to red, green and blue, but can also be other colors of light such as white light, purple light, yellow light, etc. Depending on the specific color cast of the display substrate in actual application, the technical solution of providing the expansion layer on the pixel defining layer provided at least on the periphery of the opening of the color cast light emitting device in the above embodiments can be used to improve the color cast phenomenon of the display substrate.

[0056] In the following, in embodiments of the present application, the specific structure of the display substrate and the display panel in the present application will be described by taking the light emitting device as R, G and B three types and the color cast light emitting device as the red light emitting device (R) as an example.

[0057] In embodiments of the present application, the cathode of the light emitting device actually also covers the expansion layer. In the expansion process of the expansion layer, the cathode may be deformed and thus be pulled apart, resulting in poor display of the display substrate. Therefore, the structure of the cathode can be designed to reduce the risk of breaking the cathode.

[0058] For example, in some embodiments of the present application, the cathode of the light emitting device can be prepared using a stretchable electrode material. For example, further, the cathode is prepared using any one of silver, metal nanowires, carbon nanotubes and graphene as the stretchable electrode material. When the expansion layer expands with the increase of temperature, the cathode with stretchability also stretches with the expansion of the expansion layer, thereby reducing the risk of breaking the cathode with the expansion of the expansion layer and improving the service life of the display substrate. In these embodiments, all the light emitting devices share one cathode, i.e. the cathode can be a continuous whole layer structure. For example, as shown in FIG. 1, the cathode 12 is a continuous whole layer structure covering all the light emitting devices 10. Figure 2As shown, still taking the display substrate displaying by the above-mentioned red, green and blue three primary colors as an example, the cathode 15 on the display substrate covers the pixel defining layer 12, the expansion layer 14a and the opening defined by the pixel defining layer 12. At high temperature, with the expansion of the expansion layer 14a, the cathode 15 located above the expansion layer 14a will be deformed to avoid breaking, thereby improving the service life of the cathode 15. It should be understood that, in order to improve the service life of the cathode, the thickness of the cathode can also be increased or the strength of the cathode can be enhanced by optimizing the material for preparing the cathode, such as adding a high-elasticity material in a doped manner without affecting the performance of the cathode.

[0059] In some embodiments of the present application, the edge of the cathode in the orthographic projection on the substrate-lying plane is in a curved shape. Specifically, the cathode of each light emitting device is an independent electrode and is electrically connected to each other to form a common electrode. The edge of the cathode in the orthographic projection is designed in a curved shape, so that the cathode has an outward stress release when the ambient temperature decreases and the expansion layer shrinks, so that the cathode is less likely to be damaged, thereby improving the service life of the cathode. Exemplarily, as shown in Figure 4 In the display substrate, the edge of the cathode 15 in the orthographic projection on the substrate-lying plane is in a curved shape around the opening (the area defined by the dashed line frame) of the red light emitting device 13a. The cathodes of adjacent light emitting devices can be connected to each other by wires to form a common electrode. In addition, the wires for connecting the cathodes can be designed in a curved shape to reduce the risk of being stretched and broken during the expansion of the expansion layer.

[0060] It should be noted that, in the embodiments of the present application, in the case where the edge of the cathode is in a curved shape, the curved shape can be zigzag or wavy as shown in Figure 4 In the above design, the curved shape is not limited to one shape, which not only facilitates the production and processing of the cathode, but also can select the shape of the curved shape according to different situations, thereby improving the adaptability of the cathode. It should be understood that the curved shape of the edge of the orthographic projection of each independent cathode can be the same or different, for example, having different curvatures, different numbers of wave crests, etc., which can be designed according to the structure and requirements of the light emitting device actually applied.

[0061] In the embodiments of the present application, under the premise that the expansion layer is provided around the periphery of the color-distorted light emitting device, the shape and specific distribution form of the expansion layer can be selected according to the needs of the actual process, which is not limited herein. In the following, several specific embodiments of the expansion layer are described.

[0062] In some embodiments, the part of the expansion layer surrounding the opening is in a straight line segment shape in the orthographic projection on the substrate-lying plane. Exemplarily, as shown in Figure 1 and Figure 2As shown, assuming the red light-emitting device 13a is a color-biased light-emitting device, an expansion layer 14a is provided only on the side of the pixel defining layer 12 facing away from the substrate 11, corresponding to any side of the opening of the red light-emitting device 13a. In the above solution, by minimizing the area of ​​the expansion layer 14a provided in the display substrate, the brightness of the sub-pixel corresponding to the red light-emitting device 13a is reduced, improving the color bias phenomenon of the display substrate. At the same time, it also reduces the risk of complete cathode breakage due to increased step difference around the opening caused by the expansion layer 14a. That is, in the area around the opening where the expansion layer 14a is not distributed, there is no risk of cathode breakage, thereby improving the service life of the display substrate.

[0063] Understandably, the orthographic projection of the portion of the expansion layer surrounding the opening onto the plane of the substrate is a straight line segment, and is not limited to, for example... Figure 1 The illustrated scheme can also be designed according to the specific color cast of the display substrate and the cathode configuration. For example, as shown... Figure 2 and Figure 5 As shown, assuming the red light-emitting device 13a is a color-shifting light-emitting device, an expansion layer 14a is provided on the side of the pixel defining layer 12 opposite to the substrate 11, corresponding to the two non-connected edges defining the opening of the red light-emitting device 13a. Furthermore, the expansion layers 14a are symmetrically distributed relative to the corresponding openings. In the above scheme, by designing the distribution of the expansion layers 14a, the number of expansion layers 14a is increased, effectively improving the color shift problem of the display substrate or display panel. Furthermore, by increasing the number of expansion layers 14a, the required expansion degree of each expansion layer 14a can be reduced, thereby allowing for a reduction in the thickness or width of each expansion layer 14a. This reduces the impact on the lifespan of the cathode 15 in the display substrate caused by the expansion layers 14a, thereby improving the lifespan of the display substrate.

[0064] In other embodiments, the orthographic projection of the portion of the expansion layer surrounding the opening onto the substrate surface is a non-closed ring shape. For example, as... Figure 2 and Figure 6As shown, assuming the red light-emitting device 13a is a color-shifting light-emitting device, an expansion layer 14a is provided on the side of the pixel defining layer 12 opposite to the substrate 11, corresponding to the two connected sides defining the opening of the red light-emitting device 13a, so that the orthographic projection of the expansion layer 14a is a non-closed ring. In the above solution, by increasing the number of expansion layers defining the periphery of the opening of the red light-emitting device 13a, the efficiency of reducing the light emission of the red light-emitting device 13a is improved, thereby effectively improving the color shift problem of the display substrate. Furthermore, by increasing the number of expansion layers 14a, the requirement for the degree of expansion of each expansion layer 14a can be reduced, thereby allowing the thickness or width of each expansion layer 13a to be reduced, and also reducing the risk of complete cathode breakage due to increased step difference around the opening caused by the expansion layer 14a. That is, in the area around the opening where no expansion layer 14a is distributed, there is no risk of cathode breakage, thereby improving the service life of the display substrate. Furthermore, as Figure 6 As shown, the two adjacent expansion layers 14a are not connected, so that they do not affect each other during the expansion process and thus do not generate stress interference, thereby improving the life of the expansion layer 14a. Furthermore, a reserved expandable space is provided between the two expansion layers 14a, which increases the expansion efficiency of the expansion layer 14a.

[0065] Understandably, the orthographic projection of the portion of the expansion layer surrounding the opening onto the substrate surface is a non-closed ring, and is not limited to, for example... Figure 6 The illustrated scheme can also be designed according to the specific color cast of the display substrate and the cathode configuration. For example, as shown... Figure 2 and Figure 7 As shown, assuming the red light-emitting device 13a is a color-shifting light-emitting device, an expansion layer 14a is provided on the side of the pixel defining layer 12 opposite to the substrate 11, corresponding to the three interconnected sides that define the opening of the red light-emitting device 13a. The orthographic projection of the expansion layer 14a is a non-closed ring, i.e., a U-shape. In the above technical solution, the expansion layer 14a is provided over a large area near the opening of the red light-emitting device 13a, which can effectively reduce the brightness of the sub-pixels corresponding to the red light-emitting device 13a. At the same time, the expansion layers on different sides are made into a single structure, and a notch, i.e., the U-shaped opening, is left. By reducing the stress on the expansion layer during expansion, the influence of the connection strength between the expansion layer and the pixel defining layer is reduced, thereby improving the service life of the display substrate and thus improving user satisfaction.

[0066] In other embodiments, the orthographic projection of the portion of the expansion layer surrounding the opening onto the surface of the substrate is a closed ring. For example, as... Figure 8 and Figure 9As shown, assuming that the red light emitting device 13a is a color deviation light emitting device, an expansion layer 14a is arranged on the side of the pixel defining layer 12 away from the substrate 11 on all sides of the opening defined by the red light emitting device 13a, and the shape of the orthographic projection of the expansion layer 14a is a closed ring. This design can quickly and efficiently reduce the luminous flux of the red light emitting device 14a to alleviate the color deviation of the display substrate. In this scheme, the expansion layer 14a can also be made thin or integrated into a structure to improve the service life of the display substrate.

[0067] It can be understood that there are various technical solutions for implementing the expansion layer at least partially surrounding the opening defined by the color deviation light emitting device. The design of the expansion layer can be selected according to the specific color deviation of the display substrate, the structure of the light emitting device, and the process conditions, etc. to improve the adaptability of the present application. For example, in some schemes, the distribution of the expansion layer around the opening defined by the red light emitting device can be used to design the distribution of the expansion layer around the openings defined by the green light emitting device and the blue light emitting device. Alternatively, in other schemes, the luminous flux of the color deviation light emitting device can be reduced by arranging the expansion layer only around the opening defined by the color deviation light emitting device to make the luminous flux of the color deviation light emitting device consistent or similar to that of other light emitting devices, thereby improving the color deviation problem of the display substrate. Specifically, the expansion layer can be designed according to the specific color deviation of the display substrate and its own structure design, such as whether the adjacent expansion layers are connected, how to connect, etc. In the following, the schemes of the above two cases are described in different embodiments.

[0068] In some embodiments, an expansion layer is arranged around the opening defined by each light emitting device, and the expansion coefficient of the part of the expansion layer surrounding the color deviation light emitting device is greater than the expansion coefficient of the other part of the expansion layer surrounding other light emitting devices. That is, according to the specific situation of the luminous flux of each light emitting device changing with temperature, expansion layers with different expansion coefficients are arranged respectively. In the above scheme, the luminance of the corresponding sub-pixel corresponding to each light emitting device is adjusted by the expansion layer with different expansion coefficients, so that the luminance of the corresponding sub-pixel corresponding to different light emitting devices is the same or similar, solving the problem of the luminous flux of each light emitting device changing with temperature. The luminous flux of each light emitting device changes synchronously or similarly with the increase of temperature under the same voltage, thereby improving the color deviation phenomenon of the display substrate. Specifically, the display substrate including OLED devices emitting R (red), G (green), and B (blue) light is taken as an example.

[0069] Exemplarily, as shown in FIG. 1, the display substrate includes a substrate 11, a plurality of light emitting devices 13 arranged on the substrate 11, and a plurality of sub-pixels 10 corresponding to the light emitting devices 13. The light emitting devices 13 include a red light emitting device 13a, a green light emitting device 13b, and a blue light emitting device 13c. The sub-pixels 10 include a red sub-pixel 10a corresponding to the red light emitting device 13a, a green sub-pixel 10b corresponding to the green light emitting device 13b, and a blue sub-pixel 10c corresponding to the blue light emitting device 13c. The display substrate further includes a pixel defining layer 12 arranged on the substrate 11 and surrounding the openings defined by the light emitting devices 13, and an expansion layer 14 arranged on the side of the pixel defining layer 12 away from the substrate 11 on all sides of the opening defined by the red light emitting device 13a. The shape of the orthographic projection of the expansion layer 14 is a closed ring. Figure 10 and Figure 11As shown, in this display substrate, based on the temperature-dependent decay performance of red, blue, and green light, an expansion layer 14a is provided around the opening of the red light-emitting device 13a, and an expansion layer 14b is provided around the opening of the green light-emitting device 13b. However, no expansion layer is provided around the opening of the blue light-emitting device 13c. This design takes into account that blue light has the shortest lifetime in high-temperature environments. Therefore, by reducing the brightness of the sub-pixels corresponding to the red and green light-emitting devices 13a and 13b, the brightness of red and green light is reduced, eventually becoming the same as or close to the brightness of blue light, thereby improving the color shift problem of the display substrate. Furthermore, since the lifetime of red light is longer than that of green light in high-temperature environments, when the type and concentration of thermal expansion material doped in the expansion layers 14a and 14b are the same, the thickness of the expansion layer 14a corresponding to the red light-emitting device 13a is greater than the thickness of the expansion layer 14b corresponding to the green light-emitting device 13b.

[0070] For example, such as Figure 12 and Figure 13 As shown, in this display substrate, expansion layers 14a are provided around the opening of the red light-emitting device 13a, expansion layers 14b are provided around the opening of the green light-emitting device 13b, and expansion layers 14c are provided around the opening of the blue light-emitting device 13c. By using different expansion layers 14a, 14b, and 14c to adjust the brightness of the sub-pixels corresponding to the three light-emitting devices, the brightness of the sub-pixels corresponding to the three light-emitting devices can be adjusted synchronously, thereby improving the efficiency of reducing color shift phenomena in the display substrate. Furthermore, under the premise that the thickness of the expansion layers 14a, 14b, and 14c and the type of thermal expansion material doped are the same, the concentration of thermal expansion material doped in the expansion layer 14a corresponding to the red light-emitting device 13a is greater than the concentration of thermal expansion material doped in the expansion layer 14b corresponding to the green light-emitting device 13b, and the concentration of thermal expansion material doped in the expansion layer 14b corresponding to the green light-emitting device 13b is greater than the concentration of thermal expansion material doped in the expansion layer 14c corresponding to the blue light-emitting device 13c. The selection of different types of thermal expansion materials with different coefficients of thermal expansion follows the principle of doping concentration of thermal expansion materials mentioned above, and will not be elaborated here.

[0071] Understandably, based on the temperature sensitivity differences of the red light-emitting device 13a, green light-emitting device 13b, and blue light-emitting device 13c, specific parameters of different expansion layers 14a, 14b, and 14c are designed, such as the thickness of expansion layers 14a, 14b, and 14c, the type of thermal expansion material doped in expansion layers 14a, 14b, and 14c, and the concentration of the thermal expansion material doped in expansion layers 14a, 14b, and 14c. Based on the high-temperature performance degradation of different light colors, different concentrations or different thermal expansion materials are doped into expansion layers 14a, 14b, and 14c. This causes the brightness of the sub-pixels corresponding to the three light-emitting devices to change to different degrees after the ambient temperature changes, ultimately resulting in the same or similar brightness, thereby effectively improving the color cast of the display substrate with red, green, and blue light. It should be understood that the design scheme for the expansion layer corresponding to the opening of the light-emitting device with different colors is not limited to the above example scheme. The appropriate technical solution can be selected by comprehensively considering various factors such as the specific situation of the color deviation of the display substrate, process conditions, production costs and product requirements.

[0072] In some embodiments, the expansion layers 14a, 14b, and 14c are formed by doping a thermally expanding material into the main film layer. Further, the coefficient of thermal expansion of the thermally expanding material is 10 × 10⁻⁶. -6 1 / k ~ 200*10 -6 1 / k. In the above scheme, the brightness of the sub-pixels corresponding to the light-emitting devices required to prevent color deviation or reduce color deviation of the display substrate under high temperature conditions can be calculated to determine the thermal expansion of expansion layers 14a, 14b, and 14c. This allows for the selection of thermal expansion materials with suitable coefficients of thermal expansion, enabling precise adjustment of color deviation of the display substrate.

[0073] For example, such as Figure 14 and Figure 15 As shown, the display substrate includes OLED devices that emit three colors of light: R (red), G (green), and B (blue). It is assumed that the red light-emitting device 13a and the green light-emitting device 13b are color-biased light-emitting devices. Based on the temperature-dependent decay of the RGB three-color light, expansion layers 14a and 14b are used to adjust the brightness of the sub-pixels corresponding to the red light-emitting device 13a and the green light-emitting device 13b, respectively. When the thicknesses of expansion layers 14a and 14b are equal, the coefficient of thermal expansion of the thermal expansion material doped in expansion layer 14a corresponding to the red light-emitting device 13a is 100*10⁻⁶. -6 1 / k ~ 200*10 -6 1 / k, the coefficient of thermal expansion of the thermal expansion material doped in the expansion layer 14b corresponding to the green light-emitting device 13b is 10*10. -6 1 / k ~ 50*10-6 1 / k. It can be understood that, under the premise of the thickness of the expansion layer and the category of the thermal expansion material being certain, the greater the doping concentration of the thermal expansion material, the greater the volume of the expansion layer after expansion, and the volume of the expansion layer after expansion directly affects the brightness of the sub-pixel corresponding to the red light-emitting device 13a and the green light-emitting device 13b, and thus by adjusting the size of the coefficient of the thermal expansion material doped in the expansion layer 14a, 14b, the color cast of the display substrate can be effectively improved.

[0074] Therefore, different concentrations of thermal expansion materials can be doped according to the curve of the luminous quantity of the light-emitting device changing with temperature, i.e., the temperature performance decay of the light-emitting device, and different concentrations and different expansion coefficients of thermal expansion materials can be selected according to the temperature performance of different light-emitting devices, thereby quickly and accurately solving the high-temperature color cast problem of the display substrate and reducing the impact on the service life of the display substrate.

[0075] In some embodiments, for the selection of the thermal expansion material, based on the high molecular polymer, the thermal expansion performance is good, and the species is various, so the selection range is large, and the high molecular polymer can be preferentially selected as the material doped into the expansion layer. It should be understood that the specific doped thermal expansion material is selected according to actual needs, for example: materials with high thermal expansion coefficient can select ethylene-ethyl acrylate (205*10 -6 1 / k), polyethylene (200*10 -6 1 / k), ethylene-vinyl acetate copolymer (180*10 -6 1 / k), etc. Materials with low thermal expansion coefficient can select polyamide (110*10 -6 1 / k), polycarbonate (70.2*10 -6 1 / k), etc. Among them, the thermal expansion amount of the expansion layer is calculated as: ΔL = a * L * (ΔT); a is the thermal expansion coefficient of the material; L is the initial length before expansion; ΔT: change in temperature.

[0076] For example, in at least one embodiment of the present application, the main film layer and the pixel defining layer are integrally formed. In the above-mentioned integrally formed manner, there is no physical interface between the film layers of the main film layer and the pixel defining layer, avoiding the film layers from separating, improving the stability of the film group structure, and thereby improving the service life of the display substrate.

[0077] In some embodiments of this application, the end face of the expansion layer away from the color-defining pixel layer has a guiding structure. This guiding structure is configured to increase the surface area of ​​the end face of the expansion layer away from the substrate, that is, to make the surface area of ​​the surface of the expansion layer away from the pixel-defining layer greater than the surface area of ​​the surface of the expansion layer facing the pixel-defining layer. In the above scheme, at high temperatures, the expansion layer expands. At this time, the surface of the expansion layer of the guiding structure extends along the corner of the guiding structure, which is faster than extending on a plane. Furthermore, the design of the guiding structure allows the expansion layer to expand rapidly relative to the pixel-defining layer towards its adjacent opening, reducing the expansion of the expansion layer relative to the pixel-defining layer in the direction away from the substrate. This enables more effective adjustment of the brightness of the sub-pixels corresponding to the light-emitting device and efficiently improves the color shift of the display substrate.

[0078] For example, in some embodiments, the guide structure may consist of multiple protrusions. Further, the protrusions may be linear protrusions, and the extending direction of the linear protrusions is substantially parallel to the edge of the corresponding opening. For example, as... Figure 16 and Figure 17 As shown, the expansion layer 14a, which defines the opening of the red light-emitting device 13a, has multiple linear protrusions, such as three linear protrusions 141. These multiple (three) linear protrusions 141 are parallel to each other and substantially parallel to the edge of the opening. The guide structure design in the above scheme not only increases the expansion speed of the expansion layer 14a in the direction of the opening, thereby improving the efficiency of improving the color deviation problem of the display substrate or display panel, but also reduces the stress between the expansion layer 14a and the pixel defining layer during expansion, reducing the separation between the pixel defining layer and the expansion layer 14a, thereby improving the service life of the display substrate or display panel.

[0079] For example, in other embodiments, the guide structure may be a plurality of grooves. Further, the grooves may be linear grooves, and the linear grooves intersect each other to form a cross shape and / or a grid shape. Exemplary examples include... Figure 18 and Figure 19 As shown, the expansion layer 14a, which defines the opening of the red light-emitting device 13a, has multiple linear grooves 141. Two horizontally extending linear grooves and two vertically extending linear grooves intersect each other, forming four intersection points, thus creating multiple "grid" shapes. At high temperatures, during the expansion of the expansion layer 14a, the inner surfaces of the linear grooves extend outwards in multiple directions. This not only increases the expansion speed of the expansion layer 14a towards the opening but also ensures uniform stress on the expansion layer. This improves the connection strength between the expansion layer and the pixel defining layer while reducing the impact of the expansion layer's expansion on the cathode. Therefore, it can effectively improve the color shift problem of the display substrate and also extend the lifespan of the display substrate. It should be noted that the "grid" shape can be formed by the intersection of a horizontally extending linear groove and a vertically extending linear groove, with one intersection point.

[0080] It should be understood that the guiding structure is not limited to the groove structure and the protrusion structure defined in the above embodiments, and can be selected and designed according to actual conditions, so that the groove and the protrusion present different structures, such as a U shape or other shapes.

[0081] In some embodiments of the present application, the expansion layer is a light shielding structure, so that in the process of expansion of the expansion layer, the aperture ratio of the corresponding sub-pixel is actually reduced to reduce the light emission brightness of the sub-pixel, so that the expansion amplitude of the expansion layer is reduced, thereby reducing the design parameter requirements of the expansion layer, such as the thickness, width and doping concentration of the expansion material.

[0082] In some embodiments of the present application, the expansion layer is a light shielding structure, so that in the process of expansion of the expansion layer, the aperture ratio of the corresponding sub-pixel is actually reduced to reduce the light emission brightness of the sub-pixel, so that the expansion amplitude of the expansion layer is reduced, thereby reducing the design parameter requirements of the expansion layer, such as the thickness, width and doping concentration of the expansion material.

[0083] It should be understood that the light emitting function layer in the light emitting device mentioned above at least includes a light emitting layer (EML), and can further include other functional layers, such as a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), a hole blocking layer (HBL), an electron transport layer (ETL), an electron injection layer (EIL) and the like.

[0084] The embodiments of the present application also provide a display panel, which includes any one of the display substrates in the above embodiments of the present application.

[0085] For example, the display panel provided by at least one of the embodiments of the present application can further include a touch structure to have a touch function. For example, the touch structure can be a touch panel or a touch layer. The touch panel can be arranged on the display substrate in a manner of lamination, for example, arranged on the light emitting side of the display substrate. The touch layer can be directly prepared on the display substrate, so as to facilitate the thin and light design of the display panel.

[0086] For example, the display panel in the embodiments of the present application can be a television, a digital camera, a mobile phone, a watch, a tablet computer, a notebook computer, a navigator or any product or component having a display function.

[0087] The embodiment of the present application further provides a manufacturing method of the display substrate. The manufacturing method can be used to manufacture the display substrate in the above embodiment of the present application. It should be understood that the embodiment of the manufacturing method corresponds to the embodiment of the display substrate one by one, and the repeated description is appropriately omitted for the purpose of brevity.

[0088] The manufacturing method comprises steps S110 to S140.

[0089] In step S110, a substrate is provided.

[0090] In step S120, a pixel defining layer comprising a plurality of openings is formed on one side of the substrate. The pixel defining layer is formed by a photolithography process. Further, the thickness of the pixel defining layer is 0.8um-1.2um.

[0091] In step S130, a plurality of light emitting devices are formed. Here, the light emitting devices are confined in the openings of the pixel defining layer, and part of the light emitting devices in the plurality of light emitting devices are color deviation light emitting devices.

[0092] In step S140, an expansion layer is formed on the side of the pixel defining layer away from the substrate, and the expansion layer at least partially surrounds the opening in which the color deviation light emitting device is defined. Further, the thickness of the expansion layer is 0.7um-0.9um.

[0093] In step S140, a cathode is formed on the side of the pixel defining layer and the expansion layer away from the substrate, or a cathode is formed on the side of the expansion layer away from the substrate.

[0094] In some embodiments, in step S140, the expansion layer is formed on the side of the pixel defining layer away from the substrate, and the expansion layer at least partially surrounds the opening in which the color deviation light emitting device is defined, comprising:

[0095] In step S141, the temperature variation performance decay of the light emitting device is determined according to the color deviation of the display substrate, and the color deviation light emitting device is determined. This step is used to determine which light emitting device needs to be provided with an expansion layer to change the brightness of the corresponding sub-pixel of the light emitting device.

[0096] In step S142, the expansion layer is formed by doping a thermal expansion material on the end surface of the pixel defining layer away from the substrate around the opening in which the color deviation light emitting device is defined.

[0097] In some embodiments, in step S142, doping a thermal expansion material on the end surface of the pixel definition layer away from the substrate to form the expansion layer includes: calculating the temperature performance attenuation of the color deviation light emitting device, and determining the expansion coefficient and the doping concentration of the thermal expansion material according to the calculation result. This design can accurately improve the high-temperature color deviation problem of the display panel. After the thermal expansion material is doped on the end surface of the same body as the pixel definition layer, a secondary photolithography process is performed to form the expansion layer above the pixel definition layer.

[0098] It should be understood that the above is only an exemplary solution, and the preparation of the expansion layer of the present application is not limited to the above solution, but can also be formed by doping a thermal expansion material using a pixel definition layer as a body, which can be selected and designed according to specific production conditions.

[0099] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A display substrate, characterized in that, include: Base; A pixel defining layer is located on the substrate and includes multiple openings; Multiple light-emitting devices are defined in the opening, and some of the light-emitting devices are color-biased light-emitting devices; as well as An expansion layer is located on the side of the pixel defining layer opposite to the substrate; The expansion layer at least partially surrounds and defines the opening of the color-shifting light-emitting device. When the ambient temperature of the display substrate increases, the expansion layer blocks part of the light emitted by the color-shifting light-emitting device. The end face of the expansion layer away from the color-shifting pixel defining layer has a guiding structure, which is configured to increase the surface area of ​​the end face of the expansion layer away from the substrate.

2. The display substrate according to claim 1, characterized in that, The shape of the portion of the expansion layer surrounding the opening, projected onto the surface of the substrate, is a straight line segment; or The shape of the portion of the expansion layer surrounding the opening on the surface of the substrate is a non-closed ring; or The portion of the expansion layer surrounding the opening has a closed ring shape when projected onto the surface of the substrate.

3. The display substrate according to claim 1, characterized in that, The expansion layer is disposed only around the periphery of the opening defining the color-distorting light-emitting device; or Each of the openings is surrounded by an expansion layer, and the expansion coefficient of the portion of the expansion layer surrounding the color-changing light-emitting device is greater than the expansion coefficient of the portion surrounding the other light-emitting devices.

4. The display substrate according to claim 3, characterized in that, The expansion layer is formed by doping a thermally expanding material into the main film layer.

5. The display substrate according to claim 4, characterized in that, The main film layer and the pixel defining layer are integrally formed.

6. The display substrate according to claim 4, characterized in that, The coefficient of thermal expansion of the thermal expansion material is: .

7. The display substrate according to claim 1, characterized in that, The guide structure consists of multiple protrusions, or The guide structure consists of multiple grooves.

8. The display substrate according to claim 7, characterized in that, The protrusion is a linear protrusion, and the extension direction of the linear protrusion is substantially parallel to the edge of the corresponding opening.

9. The display substrate according to claim 7, characterized in that, The grooves are linear grooves, and the linear grooves intersect each other to form a cross shape and / or a grid shape.

10. The display substrate according to any one of claims 1 to 6, characterized in that, The expansion layer has a semi-transparent structure.

11. The display substrate according to claim 10, characterized in that, The transparency of the expanded layer is 30% to 50%.

12. The display substrate according to any one of claims 1 to 6, characterized in that, The light-emitting device further includes a cathode covering the pixel defining layer and the opening, and The cathode is made of a malleable electrode material.

13. The display substrate according to claim 12, characterized in that, The stretchable electrode material includes any one or a combination of silver, metal nanowires, carbon nanotubes, and graphene.

14. The display substrate according to claim 12, characterized in that, The edge of the orthographic projection of the cathode onto the surface of the substrate is curved.

15. The display substrate according to claim 14, characterized in that, The curve shape is either sawtooth or wavy.

16. A display panel, characterized in that, The display substrate includes any one of claims 1 to 15.

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