Display panel and electronic device

Abstract

This application discloses a display panel and an electronic device. The display panel includes a substrate and light-emitting devices. The light-emitting devices of the display panel include a first light-emitting device and a second light-emitting device with two different emitting colors. Since the luminous efficiency of a single light-emitting unit in the first light-emitting device is lower than that of a single light-emitting unit in the second light-emitting device, this application improves the overall luminous efficiency of the first light-emitting device by including at least two light-emitting units stacked and connected in series, thereby reducing the power consumption of the first light-emitting device. Furthermore, the number of light-emitting units in the second light-emitting device is less than that in the first light-emitting device to reduce the difference in luminous efficiency between the two devices. This avoids excessively low driving current for the second light-emitting device at low grayscale levels, thereby improving the display uniformity of the display panel at low grayscale levels.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to a display panel and electronic device. Background Technology

[0002] A display panel is a device with display function.

[0003] Current display panels employ either single-emitting devices or series-connected devices. Series-connected devices link multiple single-emitting devices together via a connecting layer, achieving higher luminous efficiency. Therefore, to achieve the same brightness, series-connected devices require less driving current, reducing power consumption and extending lifespan.

[0004] However, the luminous efficiency of light-emitting devices of different colors in the display panel varies greatly, and the use of series-connected light-emitting devices will increase the difference in luminous efficiency. At low gray levels, the driving current of light-emitting devices with higher luminous efficiency is smaller, and even a small change in current will cause a change in brightness, resulting in poor display uniformity of the display panel at low gray levels. Utility Model Content

[0005] This application provides a display panel and an electronic device. The technical solution is as follows:

[0006] According to one aspect of this application, a display panel is provided, comprising: a substrate, and a plurality of light-emitting devices located on one side of the substrate;

[0007] The plurality of light-emitting devices include a plurality of first light-emitting devices and a plurality of second light-emitting devices, wherein the light-emitting color of the first light-emitting devices is different from the light-emitting color of the second light-emitting devices;

[0008] Each of the first light-emitting devices includes at least two light-emitting units stacked in series, and each of the second light-emitting devices includes fewer light-emitting units than each of the first light-emitting devices, wherein the luminous efficiency of a single light-emitting unit in the first light-emitting device is less than the luminous efficiency of a single light-emitting unit in the second light-emitting device.

[0009] Optionally, each of the second light-emitting devices includes one light-emitting unit, and / or each of the first light-emitting devices includes two light-emitting units.

[0010] Optionally, the light-emitting unit includes a hole injection layer, a hole transport layer, and a light-emitting layer stacked along a direction away from the substrate, wherein the hole injection layer and the hole transport layer are homojunction structures.

[0011] Optionally, the hole injection layer is a membrane structure made of a first host material and a first guest material, and the hole transport layer is a membrane structure made of the first host material.

[0012] Optionally, the light-emitting unit further includes an electron transport layer, which is located on the side of the light-emitting layer opposite to the substrate;

[0013] The first light-emitting device further includes: a connection layer located between two adjacent light-emitting units;

[0014] In the first light-emitting device, the electron transport layer that is in contact with the connecting layer and the connecting layer are homojunction structures.

[0015] Optionally, the connecting layer is a film structure made of a second host material and a second guest material; the electron transport layer is a film structure made of the second host material.

[0016] Optionally, the thickness of a single light-emitting layer in the first light-emitting device ranges from 18 nanometers to 22 nanometers;

[0017] The thickness of a single light-emitting layer in the second light-emitting device ranges from 28 nanometers to 32 nanometers, or the thickness of a single light-emitting layer in the second light-emitting device ranges from 38 nanometers to 42 nanometers.

[0018] Optionally, the light-emitting layer of at least one light-emitting unit in the first light-emitting device is a fluorescent light-emitting layer, and / or, the light-emitting layer in the second light-emitting device is a fluorescent light-emitting layer.

[0019] Optionally, the light-emitting unit further includes a microcavity adjustment layer, which is located between the hole transport layer and the light-emitting layer;

[0020] The thickness of a single microcavity adjustment layer in the first light-emitting device is less than the thickness of a single microcavity adjustment layer in the second light-emitting device.

[0021] Optionally, the thickness of a single microcavity adjustment layer in the first light-emitting device ranges from 40 nanometers to 50 nanometers;

[0022] The thickness of a single microcavity adjustment layer in the second light-emitting device ranges from 55 nanometers to 65 nanometers, or the thickness of a single microcavity adjustment layer in the second light-emitting device ranges from 95 nanometers to 105 nanometers.

[0023] Optionally, the first light-emitting device is a blue light-emitting device.

[0024] Optionally, the second light-emitting device includes a green light-emitting device and / or a red light-emitting device.

[0025] Optionally, each of the light-emitting devices includes: a first electrode, the light-emitting unit, and a second electrode stacked in a direction away from the substrate.

[0026] The first electrode of the first light-emitting device and the first electrode of the second light-emitting device are disposed in the same layer;

[0027] And / or, the second electrode of the first light-emitting device and the second electrode of the second light-emitting device are disposed in the same layer.

[0028] Optionally, the first electrode includes a first conductive layer, a reflective layer, and a second conductive layer stacked in a direction away from the substrate, wherein the thickness of the first conductive layer ranges from 3 nanometers to 12 nanometers, the thickness of the reflective layer ranges from 80 nanometers to 120 nanometers, and the thickness of the second conductive layer ranges from 7 nanometers to 12 nanometers.

[0029] And / or, the second electrode includes a third conductive layer and a fourth conductive layer stacked in a direction away from the substrate, wherein the work function of the third conductive layer is less than the work function of the fourth conductive layer, the thickness of the third conductive layer is in the range of 1 nanometer to 2 nanometers, and the thickness of the fourth conductive layer is in the range of 9 nanometers to 15 nanometers.

[0030] On the other hand, an electronic device is provided, which includes any of the above-described display panels.

[0031] The beneficial effects of the technical solutions provided in this application include at least the following:

[0032] The provided display panel includes a first light-emitting device and a second light-emitting device with two different emitting colors. Since the luminous efficiency of a single emitting unit in the first light-emitting device is lower than that of a single emitting unit in the second light-emitting device, this application improves the overall luminous efficiency of the first light-emitting device by including at least two emitting units stacked and connected in series, thereby reducing the power consumption of the first light-emitting device. Furthermore, the second light-emitting device has fewer emitting units than the first light-emitting device to reduce the difference in luminous efficiency between the two devices. This avoids excessively low driving current for the second light-emitting device at low grayscale levels, thereby improving the display uniformity of the display panel at low grayscale levels. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the structure of a display panel provided by a related technology;

[0035] Figure 2 This is a structural diagram of a display panel provided by another related technology;

[0036] Figure 3 This is a schematic diagram of the structure of a display panel provided in an embodiment of this application;

[0037] Figure 4 This is a schematic diagram of another display panel structure provided in an embodiment of this application;

[0038] Figure 5 This is a schematic diagram of another display panel structure provided in an embodiment of this application;

[0039] Figure 6 This is a schematic diagram of another display panel structure provided in an embodiment of this application;

[0040] Figure 7 This is a schematic diagram of another display panel structure provided in an embodiment of this application.

[0041] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0043] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a display panel provided by a related technology. The display panel 20 includes: a substrate 21, and a plurality of light-emitting devices 22 located on one side of the substrate 21. The plurality of light-emitting devices 22 include: a blue light-emitting device 22A, a green light-emitting device 22B, and a red light-emitting device 22C. Figure 1The light-emitting device 22 is a single light-emitting device, meaning each light-emitting device 22 includes only one light-emitting unit 222, which is located between the first electrode 221 and the second electrode 223. The luminous efficiency of the light-emitting units 222 of different colors varies considerably. Luminous efficiency is the luminous intensity per unit current, measured in candela per ampere (cd / A). For example, the luminous efficiency of the light-emitting unit 222 in the blue light-emitting device 22A is approximately 5 cd / A to 10 cd / A, the luminous efficiency of the green light-emitting device 22B is approximately 100 cd / A to 200 cd / A, and the luminous efficiency of the red light-emitting device 22C is approximately 50 cd / A to 90 cd / A.

[0044] Please refer to Figure 2 , Figure 2 This is a structural diagram of a display panel provided by another related technology. Figure 2 The light-emitting devices 22 in the display panel are tandem light-emitting devices. Each light-emitting device 22 includes two light-emitting units 222 stacked in series, and a connecting layer 224 located between two adjacent light-emitting units 222. This multiplies the luminous efficiency of the light-emitting devices 22, resulting in a multiplying difference in luminous efficiency between light-emitting devices 22 of different colors. However, to achieve the same brightness, light-emitting devices 22 with higher luminous efficiency require smaller driving currents, such as green light-emitting device 22B and red light-emitting device 22C. Therefore, at low grayscale levels, the driving current of light-emitting devices 22 with higher luminous efficiency is too small and difficult to control. Even a small change in current can cause a change in brightness, resulting in poor display uniformity of the display panel 20 at low grayscale levels.

[0045] in addition, Figure 2 The tandem light-emitting device shown leads to an increase in the number of film layers. On the one hand, it increases the number of photomasks and the number of evaporation chambers in the evaporation equipment. On the other hand, since some film layers in the tandem light-emitting device are integral structures, they are prone to lateral leakage. The increase in the number of film layers will further increase the risk of lateral leakage.

[0046] This application provides a display panel that can use active matrix organic light-emitting diode (AMOLED) technology. AMOLED technology means that each sub-pixel is controlled by a thin film transistor (TFT). AMOLED technology has advantages such as ultra-thinness and flexibility, low driving voltage, and can achieve high resolution and high contrast display effects.

[0047] Please refer to Figure 3 , Figure 3This is a schematic diagram of a display panel structure provided in an embodiment of this application. The display panel 10 includes a substrate 11 and a plurality of light-emitting devices 12 located on one side of the substrate 11. Here, the substrate 11 is used to support the plurality of light-emitting devices 12. The substrate 11 may also be provided with a driving circuit, which includes a thin-film transistor array and is electrically connected to the plurality of light-emitting devices 12. Thus, the substrate 11 can be used to drive the plurality of light-emitting devices 12 to emit light. The plurality of light-emitting devices 12 are used to emit light of different colors and brightness under the control of the driving circuit, so that the display panel 10 can realize the display function. The light-emitting device 12 provided in the exemplary embodiment of this application can be an organic light-emitting diode (OLED).

[0048] The plurality of light-emitting devices 12 includes a plurality of first light-emitting devices 12A and a plurality of second light-emitting devices 12B, wherein the light-emitting color of the first light-emitting devices 12A is different from the light-emitting color of the second light-emitting devices 12B. Here, the display panel 10 provided in the embodiments of this application may include: light-emitting devices 12 with different light-emitting colors such as red light-emitting devices, green light-emitting devices, and blue light-emitting devices.

[0049] Each first light-emitting device 12A includes at least two light-emitting units 122 stacked in series, and each second light-emitting device 12B includes fewer light-emitting units 122 than each first light-emitting device 12A includes more light-emitting units 122, wherein the luminous efficiency of a single light-emitting unit 122 in the first light-emitting device 12A is less than the luminous efficiency of a single light-emitting unit 122 in the second light-emitting device 12B.

[0050] It should be noted that the luminous efficiency of a single light-emitting unit 122 in the light-emitting device 12 depends on the characteristics of the light-emitting material. The luminous efficiency of light-emitting materials of different colors is different. In this application, the luminous efficiency of a single light-emitting unit 122 in the red light-emitting device is less than that in the green light-emitting device, and the luminous efficiency of a single light-emitting unit 122 in the red light-emitting device is greater than that in the blue light-emitting device.

[0051] For a light-emitting device 12 that includes multiple light-emitting units 122, the overall luminous efficiency of the light-emitting device 12 can be considered as the sum of the luminous efficiencies of the multiple light-emitting units 122. For a light-emitting device 12 that includes only one light-emitting unit 122, the overall luminous efficiency of the light-emitting device 12 is the luminous efficiency of the single light-emitting unit 122.

[0052] In summary, the light-emitting devices of the display panel provided in this application include a first light-emitting device and a second light-emitting device with two different emitting colors. Since the luminous efficiency of a single light-emitting unit in the first light-emitting device is lower than that of a single light-emitting unit in the second light-emitting device, this application improves the overall luminous efficiency of the first light-emitting device by setting the first light-emitting device to include at least two light-emitting units stacked and connected in series, thereby reducing the power consumption of the first light-emitting device. Furthermore, by setting the number of light-emitting units in the second light-emitting device to be less than the number of light-emitting units in the first light-emitting device, the difference in luminous efficiency between the first and second light-emitting devices is reduced, thereby avoiding excessively low driving current of the second light-emitting device at low grayscale levels, and thus improving the display uniformity of the display panel at low grayscale levels.

[0053] The quantity and type of the first and second light-emitting devices are explained below:

[0054] Alternatively, please refer to Figure 3 Each second light-emitting device 12B includes one light-emitting unit 122, and / or each first light-emitting device 12A includes two light-emitting units 122. This includes the following two cases:

[0055] 1) Each second light-emitting device 12B includes one light-emitting unit 122, and each first light-emitting device 12A includes more than two light-emitting units 122.

[0056] Please refer to Figure 4 , Figure 4 This is a schematic diagram of another display panel structure provided in an embodiment of this application. Each first light-emitting device 12A includes more than two light-emitting units 122. For example, each first light-emitting device 12A includes three light-emitting units 122. In this case, since the second light-emitting device 12B has higher luminous efficiency, this arrangement can not only reduce the difference in luminous efficiency between the first light-emitting device 12A and the second light-emitting device 12B, but also ensure that the number of film layers in the second light-emitting device 12B is smaller. This reduces the number of photomasks and the number of evaporation chambers in the vapor deposition equipment, and lowers the risk of lateral leakage.

[0057] In addition, this application can also design the number of light-emitting units 122 included in the first light-emitting device 12A based on the difference in luminous efficiency of a single light-emitting unit 122 in the first light-emitting device 12A and the second light-emitting device 12B. For example, the difference in luminous efficiency can be positively correlated with the number of light-emitting units 122 included in the first light-emitting device 12A.

[0058] 2) Each second light-emitting device 12B includes one light-emitting unit 122, and each first light-emitting device 12A includes two light-emitting units 122.

[0059] Please refer to Figure 3 In this case, since each second light-emitting device 12B includes fewer light-emitting units 122 than each first light-emitting device 12A, the number of light-emitting units 122 included in each second light-emitting device 12B is one. This configuration not only reduces the difference in luminous efficiency between the first light-emitting device 12A and the second light-emitting device 12B, but also ensures that the number of film layers in both the first light-emitting device 12A and the second light-emitting device 12B is relatively small. This reduces the number of photomasks and the number of evaporation chambers in the vapor deposition equipment, and lowers the risk of lateral leakage.

[0060] In addition to the three cases mentioned above, in this application, the number of light-emitting units 122 included in each second light-emitting device 12B may also be greater than one. However, in this case, the first light-emitting device 12A needs to be provided with more light-emitting units 122 in order to balance the difference in luminous efficiency between the first light-emitting device and the second light-emitting device.

[0061] Alternatively, please refer to Figure 5 , Figure 5 This is a schematic diagram of another display panel structure provided in an embodiment of this application. The first light-emitting device 12A is a blue light-emitting device, and the plurality of second light-emitting devices 12B include a plurality of green light-emitting devices and / or a plurality of red light-emitting devices. This includes the following three cases:

[0062] 1) The first light-emitting device 12A is a blue light-emitting device A1, and the second light-emitting device 12B is a green light-emitting device B1.

[0063] 2) The first light-emitting device 12A is a blue light-emitting device A1, and the second light-emitting device 12B is a red light-emitting device B2.

[0064] 3) The first light-emitting device 12A is a blue light-emitting device A1, and the second light-emitting device 12B includes a green light-emitting device B1 and a red light-emitting device B2.

[0065] Thus, the number of light-emitting units 122 included in the blue light-emitting device A1, green light-emitting device B1, and red light-emitting device B2 can be determined by reference. Figure 3 and Figure 4 The two scenarios shown will not be elaborated upon further in this application.

[0066] In one exemplary embodiment, please refer to Figure 6 , Figure 6This is a schematic diagram of another display panel structure provided in an embodiment of this application. The plurality of light-emitting devices 12 include: a plurality of blue light-emitting devices A1, a plurality of green light-emitting devices B1 and a plurality of red light-emitting devices B2. The blue light-emitting device A1 includes two light-emitting units 122, and the green light-emitting device B1 and the red light-emitting device B2 each include one light-emitting unit 122.

[0067] The film structure of the light-emitting device 12 is described below:

[0068] Optionally, each light-emitting device 12 includes a first electrode 121, a light-emitting unit 122, and a second electrode 123 stacked in a direction away from the substrate 11.

[0069] The first electrode 121 can be an anode, and the first electrode 121 can be used to provide holes. The manufacturing process of the first electrode 121 can include a magnetron sputtering process. The first electrode 121 can be a stacked structure. For example, the first electrode 121 includes a first conductive layer 1211, a reflective layer 1212, and a second conductive layer 1213 stacked along a direction away from the substrate 11.

[0070] The first conductive layer 1211 may be made of indium tin oxide (ITO), and its thickness ranges from 3 nm to 12 nm. The reflective layer 1212 may be made of silver (Ag), and its thickness ranges from 80 nm to 120 nm. The second conductive layer 1213 may be made of indium tin oxide (ITO), and its thickness ranges from 7 nm to 12 nm. Since both the first conductive layer 1211 and the second conductive layer 1213 are made of transparent conductive materials, by setting the reflective layer 1212 to be relatively thick, the light emitted by the light-emitting unit 122 can be reflected, thereby improving the light extraction efficiency. Therefore, the first electrode 121 can be a total internal reflection electrode.

[0071] The second electrode 123 can be a cathode, such as a common cathode. The second electrode 123 can be used to provide electrons. The manufacturing process of the first electrode 121 and the second electrode 123 can also include magnetron sputtering. The second electrode 123 can be a stacked structure. For example, the second electrode 123 includes a third conductive layer 1231 and a fourth conductive layer 1232 stacked along the direction away from the substrate 11. The work function of the third conductive layer 1231 is less than the work function of the fourth conductive layer 1232. Therefore, the third conductive layer 1231 can reduce the contact barrier between the fourth conductive layer 1232 and the light-emitting unit 122, thereby facilitating electron injection.

[0072] The material of the third conductive layer 1231 may include ytterbium (Yb), and the thickness of the third conductive layer 1231 ranges from 1 nanometer to 2 nanometers. The material of the fourth conductive layer 1232 may include magnesium (Mg) and silver (Ag), that is, the fourth conductive layer 1232 may be a magnesium-silver alloy. Magnesium-silver alloys have advantages such as low work function and high stability. Increasing the proportion of silver can reduce the thickness of the magnesium-silver alloy and increase its transmittance, so the second electrode 123 can be a semi-transparent and semi-reflective electrode. For example, the ratio of Mg to Ag is 1:9, and the thickness of the fourth conductive layer 1232 ranges from 9 nanometers to 15 nanometers.

[0073] Optionally, the first electrode 121 of the first light-emitting device 12A and the first electrode 121 of the second light-emitting device 12B are disposed on the same layer. In this way, the first electrodes 121 of multiple light-emitting devices 12 in the display panel can be manufactured in the same step, thereby saving process.

[0074] And / or, the second electrode 123 of the first light-emitting device 12A and the second electrode 123 of the second light-emitting device 12B are disposed on the same layer. In this way, the second electrodes 123 of multiple light-emitting devices 12 in the display panel can also be manufactured in the same step, thereby saving process.

[0075] The light-emitting unit 122 is driven to emit light in cooperation with the first electrode 121 and the second electrode 123. Each light-emitting unit 122 includes a light-emitting layer C1. The light-emitting process of the light-emitting unit 122 may include: under the action of an electric field, the first electrode 121 generates holes and the second electrode 123 generates electrons. When the holes provided by the first electrode 121 and the electrons provided by the second electrode 123 are transported to the light-emitting layer C1, the holes and electrons combine to generate excitons. The excitons can excite the light-emitting layer C1 to generate photons to achieve the light-emitting function.

[0076] Optionally, the thickness of the light-emitting layer C1 of different colored light-emitting devices 12 can be different. For example, the thickness of a single light-emitting layer C1 in the first light-emitting device 12A is less than the thickness of a single light-emitting layer C1 in the second light-emitting device 12B. For example, the thickness of a single light-emitting layer C1 in the blue light-emitting device A1 ranges from 18 nanometers to 22 nanometers, the thickness of a single light-emitting layer C1 in the green light-emitting device B1 ranges from 28 nanometers to 32 nanometers, and the thickness of a single light-emitting layer C1 in the red light-emitting device B2 ranges from 38 nanometers to 42 nanometers.

[0077] The luminescent layer C1 may include a host luminescent material and a guest luminescent material doped into the host luminescent material. The guest luminescent material may include phosphorescent or fluorescent materials, and the doping mass ratio of the guest material may range from 2% to 10%. When holes and electrons recombine to form excitons, paired singlet excitons and unpaired triplet excitons are generated in a 1:3 ratio according to the spin configuration. For phosphorescent materials, both triplet and singlet excitons participate in luminescence, while for fluorescent materials, only singlet excitons participate in luminescence. Therefore, the phosphorescent luminescent layer can effectively improve luminescence efficiency, but the lifetime of the phosphorescent luminescent layer is relatively low.

[0078] Optionally, the light-emitting layer C1 of at least one light-emitting unit 122 in the first light-emitting device 12A is a fluorescent light-emitting layer, and / or, the light-emitting layer C1 in the second light-emitting device 12B is a fluorescent light-emitting layer. Since the first light-emitting device 12A can be a blue light-emitting device A1, and the second light-emitting device 12B can be a green light-emitting device B1 and a red light-emitting device B2, this arrangement ensures that the lifespan of the blue light-emitting device A1, the green light-emitting device B1, and the red light-emitting device B2 is not too low, facilitating mass production. For example, Figure 6 The blue light-emitting device A1 shown includes two light-emitting units 122. The light-emitting layer C1 of one light-emitting unit is a fluorescent light-emitting layer, and the light-emitting layer C1 of the other light-emitting unit is a phosphorescent light-emitting layer, thereby taking into account both the high lifetime of the fluorescent light-emitting layer and the high luminous efficiency of the phosphorescent light-emitting layer.

[0079] In this application, the light-emitting unit also includes several film layers to form a stepped energy level state, thereby facilitating the transport of holes and electrons. The film layer structure of the light-emitting unit is described below:

[0080] Please refer to Figure 6 Each light-emitting unit 122 may further include: a hole injection layer HIL, a hole transport layer HTL, a microcavity adjustment layer C2, a hole blocking layer HBL, and an electron transport layer ETL.

[0081] The hole injection layer HIL is located between the first electrode 121 and the hole transport layer HTL. The hole injection layer HIL can be used to inject holes provided by the first electrode 121 into the hole transport layer HTL. The hole injection layer HIL can be a film structure made of a first host material and a first guest material, with the doping concentration of the first guest material ranging from 0.5% to 5.0% by mass. The thickness of the hole injection layer HIL ranges from 5 nanometers to 20 nanometers.

[0082] The hole transport layer (HTL) is located between the hole injection layer (HIL) and the microcavity adjustment layer (C2). The HTL can be used to transport holes provided by the first electrode (121) to the light-emitting layer (C1). The HTL can be made of a single material. The thickness of the HTL ranges from 18 nm to 27 nm.

[0083] Furthermore, in the first light-emitting device 12A, the hole transport layer HTL of the first light-emitting unit 122 starting from the substrate 11 can be a single-layer structure, while the hole transport layer HTL of the second light-emitting unit 122 starting from the substrate 11 can be a double-layer structure, using different materials. In the first light-emitting unit 122, holes are injected by the first electrode 121, and in the second light-emitting unit 122, holes are injected by the connecting layer 124. Since the hole injection capability of the connecting layer 124 is weaker than that of the first electrode 121, the hole transport layer HTL of the second light-emitting unit 122 adopts a double-layer structure, which facilitates the formation of stepped energy levels and is beneficial for hole transport.

[0084] Optionally, the hole injection layer HIL and the hole transport layer HTL in each light-emitting unit 122 are homojunction structures. A homojunction is a semiconductor device or interface that occurs between similar material layers with equal band gaps but different doping concentrations. That is, if the first host material of the hole injection layer HIL and the hole transport layer HTL are the same, then the hole transport layer HTL is a film structure made of the first host material. In this way, the hole injection layer HIL and the hole transport layer HTL have the same band gap, which can reduce the potential barrier for hole transport.

[0085] The microcavity adjustment layer C2 is located between the hole transport layer HTL and the light-emitting layer C1. The microcavity adjustment layer C2 can be used to adjust the cavity length of the microcavity and the transport of holes. When the first electrode 121 is a total internal reflection electrode and the second electrode 123 is a semi-transparent and semi-reflective electrode, a microcavity can be formed between the first electrode 121 and the second electrode 123. In the microcavity, light in the wavelength range corresponding to the cavity length of the microcavity can resonate, thereby the light can be enhanced by constructive interference.

[0086] Since the light-emitting devices 12 emit different colors, the wavelength range of the light emitted is different. Therefore, the cavity length of the microcavity can be adjusted by adjusting the thickness of the microcavity adjustment layer C2 so that the cavity length of the microcavity corresponds to the wavelength range of the light emitted by the light-emitting layer C1.

[0087] Optionally, the thickness of a single microcavity adjustment layer C2 in the first light-emitting device 12A is less than the thickness of a single microcavity adjustment layer C2 in the second light-emitting device 12B.

[0088] The thickness of a single microcavity adjustment layer C2 in the blue light-emitting device A1 ranges from 40 nanometers to 50 nanometers, and can be, for example, 43 nanometers, 44 nanometers, 48 ​​nanometers, or 49 nanometers; the thickness of a single microcavity adjustment layer C2 in the green light-emitting device B1 ranges from 55 nanometers to 65 nanometers, and can be, for example, 58 nanometers, 59 nanometers, 63 nanometers, or 64 nanometers; the thickness of a single microcavity adjustment layer C2 in the red light-emitting device B2 ranges from 95 nanometers to 105 nanometers, and can be, for example, 98 nanometers, 99 nanometers, 103 nanometers, or 104 nanometers.

[0089] The hole blocking layer HBL is located between the light-emitting layer C1 and the electron transport layer ETL. The hole blocking layer HBL blocks holes and transports electrons provided by the second electrode 123 to the light-emitting layer C1. The hole blocking layer HBL can be made of a single material. The thickness of the hole blocking layer HBL ranges from 5 nanometers to 10 nanometers.

[0090] An electron transport layer (ETL) is located between the hole blocking layer (HBL) and the second electrode 123. The ETL can be used to transport electrons provided by the second electrode 123 to the hole blocking layer (HBL). The ETL can include two different materials and be formed by a mixed vapor deposition process. For example, one material in the ETL can be lithium 8-hydroxyquinoline (Liq), and the proportion of Liq can be 40%, 35%, 30%, 25%, or 20%.

[0091] Optionally, a connecting layer 124 is provided between every two adjacent light-emitting units 122 in the first light-emitting device 12A. The connecting layer 124 can connect two adjacent light-emitting units 122 in series, so that multiple light-emitting units 122 in the first light-emitting device 12A can be driven at the same current density, and can transfer charge carriers (electrons or holes) between two adjacent light-emitting units 122, so as to ensure that the charge carriers can excite the light-emitting layer C1 of multiple light-emitting units 122 to emit light.

[0092] The connecting layer 124 can be a film structure made of a second host material and a second guest material. The second host material can be the same as or different from another material in the electron transport layer (ETL). The second guest material can be lithium metal (Li) or ytterbium metal (Yb), and the doping mass ratio of the second guest material can be 1%, 2%, or 3%. The thickness of the connecting layer 124 can be 10 nanometers or 15 nanometers.

[0093] In the first light-emitting device 12A, the electron transport layer (ETL) in contact with the connecting layer 124 and the connecting layer 12A form a homojunction structure. For example, the electron transport layer (ETL) of the first light-emitting unit 122, starting from the substrate 11, forms a homojunction structure with the connecting layer 124. That is, if the other material of the electron transport layer (ETL) is the same as the second main material of the connecting layer 124, then the electron transport layer (ETL) is a film structure made of the second main material. In this way, the electron transport layer (ETL) and the connecting layer 124 have the same band gap, which can reduce the potential barrier for electron transport.

[0094] The display panel provided in this application embodiment may further include a pixel defining layer and an encapsulation layer. Please refer to... Figure 7 , Figure 7 This is a schematic diagram of another display panel structure provided in an embodiment of this application. A pixel defining layer 13 is located on the substrate 11, and the pixel defining layer 13 defines multiple openings that can be used to divide multiple light-emitting devices 12. An encapsulation layer 14 can be used to encapsulate the multiple light-emitting devices 12 to prevent the intrusion of external water and oxygen. For example, the encapsulation layer 14 may include: a first inorganic encapsulation layer 141, an organic encapsulation layer 142, and a second inorganic encapsulation layer 143 stacked together.

[0095] In summary, the light-emitting devices of the display panel provided in this application include a first light-emitting device and a second light-emitting device with two different emitting colors. Since the luminous efficiency of a single light-emitting unit in the first light-emitting device is lower than that of a single light-emitting unit in the second light-emitting device, this application improves the overall luminous efficiency of the first light-emitting device by setting the first light-emitting device to include at least two light-emitting units stacked and connected in series, thereby reducing the power consumption of the first light-emitting device. Furthermore, by setting the number of light-emitting units in the second light-emitting device to be less than the number of light-emitting units in the first light-emitting device, the difference in luminous efficiency between the first and second light-emitting devices is reduced, thereby avoiding excessively low driving current of the second light-emitting device at low grayscale levels, and thus improving the display uniformity of the display panel at low grayscale levels.

[0096] On the other hand, embodiments of this application also provide an electronic device, which may include any of the display panels provided in the above embodiments. This electronic device can be various devices that include display functions, such as mobile phones, tablets, wearable devices, televisions, in-vehicle display devices, etc.

[0097] Since the electronic device includes the display panel provided in the above embodiments, it can also have a similar effect, namely, it can improve display uniformity.

[0098] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0099] In this application, the term "at least one of A and B" merely describes the relationship between related objects, indicating that three relationships can exist. For example, "at least one of A and B" can represent: A existing alone, A and B existing simultaneously, and B existing alone. Similarly, "at least one of A, B, and C" indicates that seven relationships can exist, representing: A existing alone, B existing alone, C existing alone, A and B existing simultaneously, A and C existing simultaneously, C and B existing simultaneously, and A, B, and C existing simultaneously. Likewise, "at least one of A, B, C, and D" indicates that fifteen relationships can exist, representing: A existing alone, B existing alone, C existing alone, D existing alone, A and B existing simultaneously, A and C existing simultaneously, A and D existing simultaneously, C and B existing simultaneously, D and B existing simultaneously, C and D existing simultaneously, A, B, and C existing simultaneously, A, B, and D existing simultaneously, A, C, and D existing simultaneously, and A, B, C, and D existing simultaneously.

[0100] It should be noted that the dimensions of layers and regions may be exaggerated in the accompanying drawings for clarity. Furthermore, it is understood that when an element or layer is referred to as being "on" another element or layer, it can be directly on the other element, or there may be intermediate layers. Additionally, it is understood that when an element or layer is referred to as being "below" another element or layer, it can be directly below the other element, or there may be more than one intermediate layer or element. Furthermore, it is also understood that when a layer or element is referred to as being "between" two layers or two elements, it can be the only layer between the two layers or two elements, or there may be more than one intermediate layer or element. Similar reference numerals throughout indicate similar elements.

[0101] In this application, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "multiple" means two or more, unless otherwise expressly defined.

[0102] The above description is merely an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A display panel, characterized by, include: A substrate (11), and a plurality of light-emitting devices (12) located on one side of the substrate (11). The plurality of light-emitting devices (12) includes a plurality of first light-emitting devices (12A) and a plurality of second light-emitting devices (12B), wherein the light-emitting color of the first light-emitting device (12A) is different from the light-emitting color of the second light-emitting device (12B); Each of the first light-emitting devices (12A) includes at least two light-emitting units (122) stacked in series, and each of the second light-emitting devices (12B) includes fewer light-emitting units (122) than each of the first light-emitting devices (12A), wherein the luminous efficiency of a single light-emitting unit (122) in the first light-emitting device (12A) is less than the luminous efficiency of a single light-emitting unit (122) in the second light-emitting device (12B).

2. The display panel of claim 1, wherein, Each of the second light-emitting devices (12B) includes one light-emitting unit (122), and / or each of the first light-emitting devices (12A) includes two light-emitting units (122).

3. The display panel of claim 1 or 2, wherein, The light-emitting unit includes a hole injection layer (HIL), a hole transport layer (HTL), and a light-emitting layer (C1) stacked along a direction away from the substrate (11), wherein the hole injection layer (HIL) and the hole transport layer (HTL) are homojunction structures.

4. The display panel according to claim 3, characterized in that, The hole injection layer (HIL) is a membrane structure made of a first host material and a first guest material, and the hole transport layer (HTL) is a membrane structure made of the first host material.

5. The display panel of claim 3, wherein, The light-emitting unit further includes an electron transport layer (ETL), which is located on the side of the light-emitting layer (C1) away from the substrate (11). The first light-emitting device (12A) further includes a connecting layer (124) located between two adjacent light-emitting units (122). The electron transport layer (ETL) in the first light-emitting device (12A) that is in contact with the connecting layer (124) and the connecting layer (124) are homojunction structures.

6. The display panel of claim 5, wherein, The connecting layer (124) is a film structure made of a second host material and a second guest material; the electron transport layer (ETL) is a film structure made of the second host material.

7. The display panel of claim 3, wherein, The thickness of a single light-emitting layer (C1) in the first light-emitting device (12A) ranges from 18 nanometers to 22 nanometers; The thickness of a single light-emitting layer (C1) in the second light-emitting device (12B) ranges from 28 nanometers to 32 nanometers, or the thickness of a single light-emitting layer (C1) in the second light-emitting device (12B) ranges from 38 nanometers to 42 nanometers.

8. The display panel of claim 3, wherein, The light-emitting layer (C1) of at least one light-emitting unit (122) in the first light-emitting device (12A) is a fluorescent light-emitting layer, and / or the light-emitting layer (C1) in the second light-emitting device (12B) is a fluorescent light-emitting layer.

9. The display panel of any of claims 4 to 8, wherein, The light-emitting unit (122) further includes a microcavity adjustment layer (C2), which is located between the hole transport layer (HTL) and the light-emitting layer (C1); The thickness of a single microcavity adjustment layer (C2) in the first light-emitting device (12A) is less than the thickness of a single microcavity adjustment layer (C2) in the second light-emitting device (12B).

10. The display panel of claim 9, wherein, The thickness of a single microcavity adjustment layer (C2) in the first light-emitting device (12A) ranges from 40 nanometers to 50 nanometers; The thickness of a single microcavity adjustment layer (C2) in the second light-emitting device (12B) ranges from 55 nanometers to 65 nanometers, or the thickness of a single microcavity adjustment layer (C2) in the second light-emitting device (12B) ranges from 95 nanometers to 105 nanometers.

11. The display panel of any of claims 1-2, 4-8, 10, wherein, The first light-emitting device (12A) is a blue light-emitting device.

12. The display panel of claim 11, wherein, The plurality of second light-emitting devices (12B) include a plurality of green light-emitting devices (B1) and / or a plurality of red light-emitting devices (B2).

13. The display panel of any of claims 1-2, 4-8, 10, wherein, Each of the light-emitting devices (12) includes: a first electrode (121), a light-emitting unit (122), and a second electrode (123) stacked in a direction away from the substrate (11); The first electrode (121) of the first light-emitting device (12A) and the first electrode (121) of the second light-emitting device (12B) are disposed in the same layer; And / or, the second electrode (123) of the first light-emitting device (12A) and the second electrode (123) of the second light-emitting device (12B) are disposed in the same layer.

14. The display panel of claim 13, wherein, The first electrode (121) includes a first conductive layer (1211), a reflective layer (1212), and a second conductive layer (1213) stacked in a direction away from the substrate (11), wherein the thickness of the first conductive layer (1211) ranges from 3 nanometers to 12 nanometers, the thickness of the reflective layer (1212) ranges from 80 nanometers to 120 nanometers, and the thickness of the second conductive layer (1213) ranges from 7 nanometers to 12 nanometers; And / or, the second electrode (123) includes a third conductive layer (1231) and a fourth conductive layer (1232) stacked in a direction away from the substrate (11), wherein the work function of the third conductive layer (1231) is less than the work function of the fourth conductive layer (1232), the thickness of the third conductive layer (1231) is in the range of 1 nanometer to 2 nanometers, and the thickness of the fourth conductive layer (1232) is in the range of 9 nanometers to 15 nanometers.

15. An electronic device, comprising: The electronic device includes the display panel as described in any one of claims 1 to 14.

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