Display panel and display device

Abstract

This application provides a display panel and display device. The display panel includes multiple light-emitting devices. The light-emitting layers of the first light-emitting device and the second light-emitting device are located at different positions in the thickness direction, which can reduce the leakage current path between pixels, effectively suppress sub-pixel leakage current, and improve the accuracy of display colors.

Description

Technical Field

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

[0002] In Organic Light-Emitting Diode (OLED) devices, there is a technical problem of subpixel "light leakage," which manifests as lateral current leakage between adjacent pixels, leading to color shift in the display. The reason is that the overlapping of the vapor-deposited film layers of adjacent pixels forms a leakage path. When there are differences in the activation voltages of the red (R), green (G), and blue (B) pixels in an OLED device (for example, the activation voltage of the R pixel is lower than that of the G and B pixels), and the pixel driving voltage difference is small during low-brightness, low-grayscale operation, current from one pixel can easily flow to other pixels through the leakage path, causing the pixel to emit light unnecessarily, i.e., pixel leakage, which in turn leads to abnormal display colors. Summary of the Invention

[0003] This application provides a display panel and display device that can reduce leakage current paths between pixels, effectively suppress sub-pixel leakage current, and improve the accuracy of display colors.

[0004] To achieve the above objectives, according to a first aspect of this application, a display panel is provided, comprising: Multiple light-emitting devices, each of which includes a light-emitting layer; The plurality of light-emitting devices include a first light-emitting device and a second light-emitting device spaced apart along a first direction, wherein the first light-emitting device is configured to emit a different color than the second light-emitting device, and the first direction is perpendicular to the thickness direction of the display panel; The light-emitting layer of the first light-emitting device and the light-emitting layer of the second light-emitting device are located at different positions in the thickness direction of the display panel.

[0005] Optionally, the light-emitting device includes a first electrode and a second electrode disposed opposite to each other, an organic functional layer is included between the first electrode and the second electrode, the organic functional layer includes the light-emitting layer, and the organic functional layer is connected to the first electrode to form a first interface; The first light-emitting device has a first light-emitting center in its light-emitting layer, and the second light-emitting device has a second light-emitting center in its light-emitting layer. The distance between the first light-emitting center and the first interface is d1=(2m-1)×1 / 4×λ1, and the distance between the second light-emitting center and the first interface is d2=(2n-1)×1 / 4×λ2. Where m and n are both positive integers greater than or equal to 1, and m is not equal to n; λ1 is the wavelength corresponding to the emission peak of the first light-emitting device, and λ2 is the wavelength corresponding to the emission peak of the second light-emitting device.

[0006] Optionally, mn=1.

[0007] Optionally, m=2, n=1.

[0008] Optionally, the organic functional layer includes a first organic functional sublayer located between the first electrode and the light-emitting layer; m is greater than n, and the thickness of the first organic functional sublayer of the first light-emitting device is greater than the thickness of the first organic functional sublayer of the second light-emitting device.

[0009] Optionally, one of the first light-emitting device and the second light-emitting device is configured to have a peak emission value in the red band, and the other is configured to have a peak emission value in the green band.

[0010] Optionally, the first organic functional sublayer is selected from the hole transport layer, λ1 is located in the red light band, λ2 is located in the green light band, and the thickness of the hole transport layer of the first light-emitting device is greater than the thickness of the hole transport layer of the second light-emitting device.

[0011] Optionally, the plurality of light-emitting devices further includes a third light-emitting device, which is configured to emit a different color than the first and second light-emitting devices. The multiple light-emitting devices emit light together to form mixed light. In the mixed light, the light intensity ratio of the third light-emitting device is less than that of the first light-emitting device and less than that of the second light-emitting device. The light-emitting layer of the third light-emitting device has a third light-emitting center, and the distance between the third light-emitting center and the first interface is d3=(2a-1)×1 / 4×λ3; Wherein, λ3 is the wavelength corresponding to the emission peak of the third light-emitting device, a is a positive integer, and a = m or n.

[0012] Optionally, m is greater than n, and a = n.

[0013] A second aspect of this application also provides a display device, the display device including the above-described display panel.

[0014] This application provides a display panel and display device. The display panel includes multiple light-emitting devices, wherein the light-emitting layers of the first light-emitting device and the second light-emitting device are located at different positions in the thickness direction, which can reduce the leakage current path between pixels, effectively suppress sub-pixel leakage current, and improve the accuracy of display colors.

[0015] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description 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 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.

[0016] Figure 1 This is a schematic diagram of a display panel structure according to an embodiment of this application; Figure 2 This is a schematic diagram of the display panel structure according to another embodiment of this application; Figure 3 This is a schematic diagram of the display panel structure according to another embodiment of this application; Explanation of reference numerals in the attached figures: 100. Display panel; 1. Array substrate; 2. Light-emitting device; 2a. First light-emitting device; 2b. Second light-emitting device; 2c. Third light-emitting device; 20. First interface; 21. First electrode; 22. Organic functional layer; 221. Hole injection layer; 222. First organic functional sublayer; 223. Microcavity adjustment layer; 224. Light-emitting layer; 225. Electron transport layer; 226. Electron injection and conduction composite layer; 227. Electron injection layer; 23. Second electrode; 24. Cover layer; 25. Protective layer; 3. Packaging structure.

[0017] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0019] Existing OLED devices suffer from pixel stealth. To solve this problem, see [link to relevant documentation]. Figures 1-3The first aspect of this application provides a display panel 100, which includes a plurality of light-emitting devices 2, each of which includes a light-emitting layer 224. Along a first direction perpendicular to the thickness direction of the display panel 100, the plurality of light-emitting devices 2 include a first light-emitting device 2a and a second light-emitting device 2b disposed at intervals. The first light-emitting device 2a is configured to emit a different color than the second light-emitting device 2b. The light-emitting layers 224 of the first light-emitting device 2a and the second light-emitting device 2b are located at different positions in the thickness direction (x) of the display panel 100.

[0020] The display panel 100 provided in this application includes multiple light-emitting devices 2, wherein the light-emitting layers 224 of the first light-emitting device 2a and the second light-emitting device 2b are located at different positions in the thickness direction, which can reduce the leakage current path between pixels, effectively suppress the leakage current of sub-pixels, and improve the accuracy of display colors.

[0021] In some embodiments, the light-emitting device 2 includes a first electrode 21 and a second electrode 23 disposed opposite to each other. An organic functional layer 22 is included between the first electrode 21 and the second electrode 23. The organic functional layer 22 includes a light-emitting layer 224, and the organic functional layer 22 is connected to the first electrode 21 to form a first interface 20. The distance between the first light-emitting center and the first interface 20 is d1=(2m-1)×1 / 4×λ1, and the distance between the second light-emitting center and the first interface 20 is d2=(2n-1)×1 / 4×λ2. Wherein, m and n are both positive integers greater than or equal to 1, and m is not equal to n. λ1 is the wavelength corresponding to the emission peak of the first light-emitting device 2a, and λ2 is the wavelength corresponding to the emission peak of the second light-emitting device 2b.

[0022] It is understood that, in the embodiments of this application, the term "light-emitting center" refers to the location in the light-emitting layer 224 where holes and electrons form excitons, which can typically be measured using a single-carrier device.

[0023] In this embodiment, the organic functional layer 22 may include multiple organic functional layer sub-layers, such as a hole injection layer 221 (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), an emitting layer 224 (EML), a hole blocking layer (HBL), an electron transport layer 225 (ETL), and an electron injection layer 227 (EIL). The first interface 20 is the contact surface between the organic functional layer 22 and the first electrode 21, and is a reflective surface in the optical cavity structure (the resonant cavity structure formed by the first electrode 21 and the second electrode 23), participating in optical resonance modulation.

[0024] This application sets the distance between the first light-emitting center and the first interface 20 to d1 = (2m-1) × 1 / 4 × λ1, and the distance between the second light-emitting center and the first interface 20 to d2 = (2n-1) × 1 / 4 × λ2. Setting the distances between the first and second light-emitting centers and the first interface 20 to odd multiples of a quarter wavelength of the corresponding emission peak wavelength λ1 or λ2 can improve the extraction efficiency and color purity of the target wavelength light through the coherent enhancement effect of the optical cavity, and reduce viewing angle color shift, thereby optimizing the optical display performance of the OLED device. Where m is not equal to n, light-emitting devices 2 of different emission colors are located at different light-emitting nodes. When the light-emitting layers 224 of the first light-emitting device 2a and the second light-emitting device 2b avoid each other in thickness, excellent optical performance can be maintained. In some embodiments, mn=1. In this case, the first light-emitting center and the second light-emitting center are located at adjacent light-emitting nodes, which avoids the increase in the overall power consumption of the display panel 100 due to the excessive voltage difference between different pixels, which would lead to a higher driving voltage.

[0025] For example, m=2, n=1, that is, the first light-emitting center is located at 3λ1 / 4 and the second light-emitting center is located at 1λ1 / 4, which ensures that the start-up voltage of the light-emitting device 2 is low, greatly simplifying the design and manufacturing process of the thickness of the organic functional layer 22.

[0026] In this embodiment, by adjusting the thickness of the organic functional sublayer located between the first electrode 21 and the light-emitting layer 224, the purpose of having the light-emitting center located at different light-emitting nodes is achieved. For example, the organic functional layer 22 includes a first organic functional sublayer 222 located between the first electrode 21 and the light-emitting layer 224. When m is greater than n, the thickness of the first organic functional sublayer 222 of the first light-emitting device 2a is greater than the thickness of the first organic functional sublayer 222 of the second light-emitting device 2b.

[0027] The organic functional sublayer located between the first electrode 21 and the light-emitting layer 224 includes HIL, HTL, microcavity adjustment layer 223 (FL), etc. The HTL is made of hole transport material and is usually thicker than other organic functional sublayers of the first electrode 21 and the light-emitting layer 224, providing more adjustment space. Therefore, the first organic functional sublayer 222 includes or is selected from HTL. When m > n, the HTL of the first light-emitting device 2a is greater than that of the second light-emitting device 2b, and the light-emitting center can be adjusted to the corresponding position. For example, when the first light-emitting device 2a is configured to have a light emission peak in the red light band, and the second light-emitting device 2b is configured to have a light emission peak in the green light band, m=2, n=1, and the HTL of the first light-emitting device 2a and the HTL of the second light-emitting device 2b differ by at least 500 Å. Specifically, the film thickness of the first light-emitting device 2a is in the range of 1100~1400 Å, and the film thickness of the second light-emitting device 2b is in the range of 100~400 Å.

[0028] It is understood that in the embodiments of this application, after adjusting the positions of the first light-emitting center and the second light-emitting center by HTL, the distance between the first electrode 21 and the second electrode 23 will also be different. For example, the distance between the first electrode 21 and the second electrode 23 of the first light-emitting device 2a is in the range of 2590~3190 Å, and the distance between the first electrode 21 and the second electrode 23 of the second light-emitting device 2b is in the range of 1010~1610 Å.

[0029] Of course, it is understandable that in this embodiment, one of the first light-emitting device 2a and the second light-emitting device 2b is configured to have a peak emission value in the red band, and the other is configured to have a peak emission value in the green band. The first light-emitting device 2a is configured to have a peak emission value in the red band (i.e., λ1 and λ2 are both in the red band), and the second light-emitting device 2b is configured to have a peak emission value in the green band. That is, red light has a longer wavelength, and the emission center of the light-emitting layer 224 of the red-emitting device needs to be furthest from the reflective interface. When the first light-emitting device 2a is configured to emit red light, the adjustment required is smaller than when it is configured to emit green or blue light, further reducing process costs.

[0030] In some embodiments, the plurality of light-emitting devices 2 further includes a third light-emitting device 2c, which is configured to emit a different color than the first light-emitting device 2a and the second light-emitting device 2b. The plurality of light-emitting devices 2 emit light together to form mixed light. In the mixed light, the light intensity ratio of the third light-emitting device 2c is less than that of the first light-emitting device 2a and less than that of the second light-emitting device 2b. The light-emitting layer 224 of the third light-emitting device 2c has a third light-emitting center. The distance between the third light-emitting center and the first interface 20 is d3 = (2a-1) × 1 / 4 × λ3. Wherein, λ3 is the light intensity ratio of the light-emitting peak of the third light-emitting device 2c. When the light intensity ratio is less than that of the second light-emitting device 2b, the overall display effect of the display panel 100 is less under low grayscale working conditions. At this time, its light-emitting center can be set to be the same as that of the first light-emitting device 2a or the second light-emitting device 2b, so that the cross voltage of the light-emitting device 2 located at the same light-emitting node is reduced, which is more conducive to reducing the driving voltage.

[0031] It is understood that in the embodiments of this application, λ1, λ2 and λ3 are obtained by detecting the light emitted by their respective corresponding light-emitting devices 2.

[0032] See Figure 1 For example, a=m, meaning the third light-emitting center and the first light-emitting center are located at the same light-emitting node. In this design, a common HTL material can be deposited first, and then a thicker HTL material can be deposited on a fine metal mask (FMM) with the openings aligned with the positions of the first light-emitting device 2a and the third light-emitting device 2c. This makes the first light-emitting center and the third light-emitting center located at the same light-emitting node, and different from the light-emitting node of the second light-emitting center.

[0033] It is understood that, in the embodiments of this application, the organic functional layer 22 further includes a microcavity conditioning layer 223 (Functional Layer, abbreviated as FL) located between the first organic functional sublayer 222 and the light-emitting layer 224.

[0034] When FL is present, the FL material of the first light-emitting device 2a and the HTL material of the second vapor deposition are vapor deposited using the FMM cavity aligned with the first light-emitting device 2a, and the FL material of the third light-emitting device 2c and the HTL material of the second vapor deposition are vapor deposited using the FMM cavity aligned with the third light-emitting device 2c.

[0035] See Figure 2For example, a=n, that is, the third light-emitting center 205c and the second light-emitting center are located at the same light-emitting node. In this design, a common HTL material can be deposited first, and then a fine metal mask (FMM) with the opening aligned only with the first light-emitting device 2a can be used to deposit a thicker HTL material, so that the second light-emitting center and the third light-emitting center are located at the same light-emitting node, and the light-emitting node is different from that of the first light-emitting center.

[0036] When FL is present, the FL material of the first light-emitting device 2a and the HTL material of the second evaporation are evaporated using the FMM cavity aligned with the first light-emitting device 2a.

[0037] In some preferred embodiments, m is greater than n, and a = n. That is, the third light-emitting center is located at the same light-emitting node as the second light-emitting center, reducing the raw materials required for the fabrication of the third light-emitting device 2c and helping to control the fabrication cost. Moreover, when a = n, only one opening needs to be used in the process of fabricating the HTL to align with the FMM of the first light-emitting device 2a, reducing the process difficulty and cost.

[0038] Furthermore, in some embodiments, the third light-emitting device 2c is configured to have a peak emission value in the blue band.

[0039] It is understood that in the embodiments of this application, one of the first electrode 21 and the second electrode 23 is an anode and the other is a cathode.

[0040] It is understood that in the embodiments of this application, the red light band is 620 nm to 750 nm, the green light band is 495 nm to 570 nm, and the blue light band is 450 nm to 490 nm.

[0041] In some embodiments, the organic functional layer 22 further includes a HIL located between the HTL and the first electrode 21, an ETL located on the side of the light-emitting layer 224 away from the FL, an electron injection and conduction composite layer 226 (EICL) located on the side of the ETL away from the light-emitting layer 224, an EIL located on the side of the EICL, and a second electrode 23 located on the side of the EIL away from the EICL.

[0042] In some embodiments, the light-emitting device 2 further includes a capping layer 24 (CPL) located on the side of the second electrode 23 away from the light-emitting layer 224, and a protective layer 25 located on the side of the CPL away from the second electrode 23.

[0043] It is understood that in the embodiments of this application, the first electrode 21, second electrode 23, HIL, ETL, EICL, EIL, and CPL of each light-emitting device 2 can be set individually or shared by multiple light-emitting devices 2. For example, each light-emitting device 2 has an independent first electrode 21 and HIL, and multiple light-emitting devices 2 share ETL, EICL, EIL, and CPL. In this embodiment, the HIL material can be formed by HTL doping with P-type dopant material, the ETL material includes Liq, and the EIL material includes Yb.

[0044] In this embodiment, the first electrode 21 is made of a reflective material, and the second electrode 23 is made of a translucent material. In some specific embodiments, the first electrode 21 includes a first ITO layer, a metal Ag material layer, and a second ITO layer, which are stacked together. The second electrode 23 is made of Ag and Mg.

[0045] See Figure 3 In some embodiments, the display panel 100 further includes an encapsulation structure 3 and an array substrate 1, with the light-emitting device 2 located on the array substrate 1. The encapsulation structure 3 covers the array substrate 1 and the light-emitting device 2. The array substrate 1 is used to drive the light-emitting device 2, and the encapsulation structure 3 is used to protect the array substrate 1 and the light-emitting device 2, preventing water and oxygen intrusion and reducing the probability of corrosion of the light-emitting device 2.

[0046] In some embodiments, the array substrate 1 includes a substrate and a thin-film transistor layer disposed on the substrate.

[0047] In some embodiments, the substrate can be a rigid substrate, such as a glass substrate; or, the substrate can be a flexible substrate, such as a substrate formed of polyimide. When the substrate is a flexible substrate, the substrate can be formed of multiple sub-substrates of the same material, such as polyimide, and adjacent sub-substrates are bonded together by adhesive sub-layers.

[0048] In some embodiments, the thin-film transistor layer includes a thin-film transistor, which includes a semiconductor located on a substrate. The semiconductor may be formed of polycrystalline silicon or a metal oxide (such as indium gallium zinc oxide). The semiconductor is divided into a channel region and source and drain regions formed on either side of the channel region. The thin-film transistor layer also includes a first gate insulating layer covering the semiconductor. The thin-film transistor also includes a first gate formed on the first gate insulating layer, overlapping the channel region. The first gate may be formed as multiple layers or a single layer comprising a low-resistance material such as Al, Ti, Mo, Cu, Ni, or alloys thereof, or a material with high corrosion resistance. The thin-film transistor layer also includes a second gate insulating layer covering the first gate. The thin-film transistor also includes a second gate located on the second gate insulating layer, overlapping the first gate. The second gate may be formed as multiple layers or a single layer comprising a low-resistance material such as Al, Ti, Mo, Cu, Ni, or alloys thereof, or a material with high corrosion resistance. The thin-film transistor layer also includes a first interlayer insulating layer formed on the second gate. The first interlayer insulating layer, the first gate insulating layer, and the second gate insulating layer include source contact holes and drain contact holes, and the source region and the drain region are exposed through the source contact holes and drain contact holes, respectively.

[0049] The thin-film transistor also includes a source and a drain disposed on the same layer. Both the source and drain are formed on the first interlayer insulating layer. The source is connected to the source region through a source contact hole, and the drain is connected to the drain region through a drain contact hole. The source and drain can be multiple layers or a single layer formed of low-resistance materials such as Al, Ti, Mo, Cu, Ni, or their alloys, or materials with high corrosion resistance. For example, the source and drain can be a triple layer of Ti / Cu / Ti, Ti / Ag / Ti, Ti / Al / Ti, or Mo / Al / Mo, or other single-layer or multi-layer structures.

[0050] In some embodiments, the thin-film transistor layer further includes at least one planarization layer located on the side of the first interlayer insulating layer away from the substrate, the at least one planarization layer covering the source and drain.

[0051] A second aspect of this application also provides a display device, which includes the display panel 100 of the foregoing embodiment.

[0052] A display device is an electronic device capable of receiving, processing, and displaying image or video information. It typically consists of a display panel 100, a driving circuit, a control unit, a power module, and a housing. For example, a display device could be a smartphone, where the display panel 100 is integrated into the phone's overall structure to provide a user interface and display multimedia content; or it could be a television set, where the display panel 100 serves as the core component, using a driving circuit and control unit to display large-size images. As a final product, the design of a display device must ensure that all internal components work together to provide the expected display performance and user experience.

[0053] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0054] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0055] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0056] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A display panel, characterized in that, include: Multiple light-emitting devices, each of which includes a light-emitting layer; The plurality of light-emitting devices include a first light-emitting device and a second light-emitting device spaced apart along a first direction, wherein the first light-emitting device is configured to emit a different color than the second light-emitting device, and the first direction is perpendicular to the thickness direction of the display panel; The light-emitting layer of the first light-emitting device and the light-emitting layer of the second light-emitting device are located at different positions in the thickness direction of the display panel.

2. The display panel according to claim 1, characterized in that, The light-emitting device includes a first electrode and a second electrode disposed opposite to each other, an organic functional layer is included between the first electrode and the second electrode, the organic functional layer includes the light-emitting layer, and the organic functional layer is connected to the first electrode to form a first interface; The first light-emitting device has a first light-emitting center in its light-emitting layer, and the second light-emitting device has a second light-emitting center in its light-emitting layer. The distance between the first light-emitting center and the first interface is d1=(2m-1)×1 / 4×λ1, and the distance between the second light-emitting center and the first interface is d2=(2n-1)×1 / 4×λ2. Where m and n are both positive integers greater than or equal to 1, and m is not equal to n; λ1 is the wavelength corresponding to the emission peak of the first light-emitting device, and λ2 is the wavelength corresponding to the emission peak of the second light-emitting device.

3. The display panel according to claim 2, characterized in that, mn=1.

4. The display panel according to claim 2, characterized in that, m=2, n=1.

5. The display panel according to claim 2, characterized in that, The organic functional layer includes a first organic functional sublayer located between the first electrode and the light-emitting layer; m is greater than n, and the thickness of the first organic functional sublayer of the first light-emitting device is greater than the thickness of the first organic functional sublayer of the second light-emitting device.

6. The display panel according to any one of claims 1 to 5, characterized in that, One of the first light-emitting device and the second light-emitting device is configured to have a light emission peak in the red band, and the other of the first light-emitting device and the second light-emitting device is configured to have a light emission peak in the green band.

7. The display panel according to claim 5, characterized in that, The first organic functional sublayer includes a hole transport layer, λ1 is located in the red light band, λ2 is located in the green light band, and the thickness of the hole transport layer of the first light-emitting device is greater than the thickness of the hole transport layer of the second light-emitting device.

8. The display panel according to claim 2, characterized in that, The plurality of light-emitting devices further includes a third light-emitting device, which is configured to emit a different color than both the first and second light-emitting devices. The multiple light-emitting devices emit light together to form mixed light. In the mixed light, the light intensity ratio of the third light-emitting device is less than that of the first light-emitting device and less than that of the second light-emitting device. The light-emitting layer of the third light-emitting device has a third light-emitting center, and the distance between the third light-emitting center and the first interface is d3=(2a-1)×1 / 4×λ3; Wherein, λ3 is the wavelength corresponding to the emission peak of the third light-emitting device, a is a positive integer, and a = m or n.

9. The display panel according to claim 8, characterized in that, m is greater than n, and a = n.

10. A display device, characterized in that, The display device includes a display panel as described in any one of claims 1 to 9.

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