Patent Publication Number: US-2023138001-A1

Title: Display panel and display device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     For all purposes, the present application claims priority to the Chinese patent application No. 202120339751.1 filed on Feb. 3, 2021, the disclosure of which is incorporated herein by reference in its entirety as part of the embodiment of the present disclosure. 
     TECHNICAL FIELD 
     At least one embodiment of the present disclosure relates to a display panel and a display device. 
     BACKGROUND 
     Generally, driving transistors in drive circuits of pixel units that emit light of different colors have a same width-to-length ratio of a channel. 
     SUMMARY 
     At least one embodiment of the present disclosure relates to a display panel and a display device. 
     At least one embodiment of the present disclosure provides a display panel including: a plurality of pixel units, each of the plurality of pixel units includes a pixel circuit and a light-emitting element, the pixel circuit is configured to drive the light-emitting element, the pixel circuit includes a driving transistor, the plurality of pixel units include a first pixel unit and a second pixel unit, the first pixel unit is configured to emit light of a first color, the second pixel unit is configured to emit light of a second color, the driving transistor of the pixel circuit of the first pixel unit includes a first channel, and the driving transistor of the pixel circuit of the second pixel unit includes a second channel, a width-to-length ratio of the first channel is greater than a width-to-length ratio of the second channel, and a shape of the first channel is different from a shape of the second channel. 
     For example, a width of the first channel is the same as a width of the second channel, and a length of the first channel is less than a length of the second channel. 
     For example, the shape of the first channel includes a U-shape. 
     For example, the shape of the second channel includes a mirror image of S-shape, a serpentine shape, a square waveform, a zigzag shape, or a double U-shape. 
     For example, the shape of the second channel includes a double U-shape, and the double U-shape includes a first U-shaped portion and a second U-shaped portion, the first U-shaped portion and the second U-shaped portion share a same side, and opening directions of the first U-shaped portion and the second U-shaped portion are different. 
     For example, the second channel includes a first portion, a second portion, a third portion, a fourth portion, and a fifth portion that are connected in sequence, the first portion, the third portion, and the fifth portion all extend in a first direction X, both the second portion and the fourth portion extend in a second direction Y, the first direction X intersects with the second direction Y. 
     For example, the plurality of pixel units further includes a third pixel unit, the third pixel unit is configured to emit light of a third color, the driving transistor of the pixel circuit of the third pixel unit includes a third channel, and the width-to-length ratio of the first channel is different from a width-to-length ratio of the third channel. 
     For example, the width-to-length ratio of the first channel, the width-to-length ratio of the second channel, and the width-to-length ratio of the third channel are different from one another. 
     For example, the width-to-length ratio of the second channel is greater than or equal to the width-to-length ratio of the third channel. 
     For example, a shape of the third channel is the same as the shape of the second channel. 
     For example, the shape of the third channel includes a mirror image of S-shape, a serpentine shape, a square waveform, a zigzag shape, or a double U-shape. 
     For example, a width of the third channel is the same as a width of the second channel, and a length of the third channel is greater than or equal to a length of the second channel. 
     For example, the pixel circuit further includes a storage capacitor, a first transistor, a second transistor, a third transistor, and a fourth transistor, a first electrode plate of the storage capacitor is connected with a gate electrode of the driving transistor, a second electrode plate of the storage capacitor is connected with a first power supply line, and a first electrode of the driving transistor is connected with the first power supply line, a gate electrode of the first transistor is connected with a gate line, a first electrode of the first transistor is connected with the first electrode of the driving transistor, a second electrode of the first transistor is connected with a data line, a gate electrode of the second transistor is connected with the gate line, a first electrode of the second transistor is connected with a second electrode of the driving transistor, and a second electrode of the second transistor is connected with the gate electrode of the driving transistor, a gate electrode of the third transistor is connected with a light-emitting control signal line, a first electrode of the third transistor is connected with the second electrode of the driving transistor, and a second electrode of the third transistor is connected with a first electrode of the light-emitting element, a second electrode of the light-emitting element is connected with a second power supply line, a gate electrode of the fourth transistor is connected with a reset control signal line, a first electrode of the fourth transistor is connected with the gate electrode of the driving transistor, and a second electrode of the fourth transistor is connected with an initialization signal line. 
     For example, the display panel further includes a first connection electrode, a second connection electrode, and a third connection electrode, one end of the first connection electrode is connected with the first electrode of the light-emitting element, and the other end of the first connection electrode is connected with the second electrode of the third transistor; the second electrode plate of the storage capacitor has an opening, one end of the second connection electrode passes through the opening and is connected with the gate electrode of the driving transistor, and the other end of the second connection electrode is connected with the first electrode of the fourth transistor and the second electrode of the second transistor; one end of the third connection electrode is connected with the second electrode of the fourth transistor, and the other end of the third connection electrode is connected with the initialization signal line. 
     For example, the display panel further includes a base substrate, the pixel unit is located on the base substrate, and the driving transistor of the pixel circuit of the first pixel unit includes a first gate electrode, the driving transistor of the pixel circuit of the second pixel unit includes a second gate electrode, an orthographic projection of the first gate electrode on the base substrate partially overlaps with an orthographic projection of the first channel on the base substrate, an orthographic projection of the second gate electrode on the base substrate partially overlaps with an orthographic projection of the second channel on the base substrate. 
     For example, the display panel further includes a base substrate, the pixel unit is located on the base substrate, and the driving transistor of the pixel circuit of the third pixel unit includes a third electrode, an orthographic projection of the third gate electrode on the base substrate partially overlaps with an orthographic projection of the third channel on the base substrate. 
     For example, the first pixel unit includes a pixel unit emitting blue light, the second pixel unit includes a pixel unit emitting red light, and the third pixel unit includes a pixel unit emitting green light. 
     For example, the light-emitting element includes an organic light-emitting diode, and the display panel includes an organic light-emitting diode display panel. 
     At least one embodiment of the present disclosure provides a display device including any one of the display panels as described above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Hereinafter, the drawings accompanying embodiments of the present disclosure are simply introduced in order to more clearly explain technical solution(s) of the embodiments of the present disclosure. Obviously, the described drawings below are merely related to some of the embodiments of the present disclosure without constituting any limitation thereto. 
         FIG.  1    is a diagram illustrating a principle of a pixel circuit of a display panel provided by an embodiment of the present disclosure. 
         FIG.  2    is a pixel layout diagram of the display panel provided by an embodiment of the present disclosure. 
         FIG.  3 A  is a plan view of an active layer in the display panel provided by an embodiment of the present disclosure. 
         FIG.  3 B  is a plan view of an active layer in the display panel provided by an embodiment of the present disclosure. 
         FIG.  3 C  is a plan view of a first conductive layer in the display panel provided by an embodiment of the present disclosure. 
         FIG.  3 D  is a plan view of the active layer and the first conductive layer in the display panel provided by an embodiment of the present disclosure. 
         FIG.  3 E  is a plan view of a second conductive layer in the display panel provided by an embodiment of the present disclosure. 
         FIG.  3 F  is a plan view of a via hole penetrating at least one of a first insulating layer, a second insulating layer, and a third insulating layer in the display panel provided by an embodiment of the present disclosure. 
         FIG.  3 G  is a plan view of a third conductive layer in the display panel provided by an embodiment of the present disclosure. 
         FIG.  3 H  is a plan view of a via hole penetrating a fourth insulating layer in the display panel provided by an embodiment of the present disclosure. 
         FIG.  3 I  is a plan view of a first electrode layer in the display panel provided by an embodiment of the present disclosure. 
         FIG.  4    is a cross-sectional view taken along line A-B of  FIG.  2   . 
         FIG.  5    is a cross-sectional view taken along line E-F of  FIG.  2   . 
     
    
    
     DETAILED DESCRIPTION 
     In order to make objectives, technical details and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be described in a clearly and fully understandable way in connection with the drawings related to the embodiments of the present disclosure. Apparently, the described embodiments are just a part but not all of the embodiments of the present disclosure. Based on the described embodiments herein, those skilled in the art can obtain other embodiment(s), without any inventive work, which should be within the scope of the present disclosure. 
     Unless otherwise defined, all the technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. The terms “first,” “second,” etc., which are used in the present disclosure, are not intended to indicate any sequence, amount or importance, but distinguish various components. Also, the terms “comprise,” “comprising,” “include,” “including,” etc., are intended to specify that the elements or the objects stated before these terms encompass the elements or the objects and equivalents thereof listed after these terms, but do not preclude the other elements or objects. The phrases “connect”, “connected”, etc., are not intended to define a physical connection or mechanical connection, but may include an electrical connection, directly or indirectly. The terms “on,” “under,” “right,” “left” and the like are only used to indicate relative position relationship, and when the position of the described object is changed, the relative position relationship may be changed accordingly. 
     For an electroluminescent display device, a pixel unit includes a driving circuit and a light-emitting element, and the pixel circuit is configured to drive the light-emitting element. For example, the pixel circuit is configured to drive the light-emitting element to emit light. For example, the pixel circuit is configured to provide a drive current to drive the light-emitting element to emit light. 
     For example, the light-emitting element includes a first electrode, a second electrode, and a light-emitting layer between the first electrode and the second electrode. Because efficiencies and lifespans of the light-emitting layers in the pixel units emitting light of different colors are different, driving transistors with the same width-to-length ratio will lead to problems of poor display uniformity and short display lifespan. 
       FIG.  1    is a diagram illustrating a principle of a pixel circuit of a display panel provided by an embodiment of the present disclosure.  FIG.  2    is a pixel layout diagram of the display panel provided by an embodiment of the present disclosure. Please refer to  FIG.  1    and  FIG.  2    together, a display panel  100  includes a plurality of pixel units  101 . For example, the plurality of pixel units  101  are arranged in a matrix, but not limited thereto. For example, each pixel unit  101  of the plurality of pixel units  101  includes a pixel circuit  10  and a light-emitting element  20 , and the pixel circuit  10  is configured to drive the light-emitting element  20 . For example, each pixel unit  101  includes a pixel circuit  10 , a light-emitting element  20 , a gate line GL, a data line DL, and a voltage signal line (including at least one of a first power supply line PL 1 , a second power supply line PL 2 , a light-emitting control signal line EML, an initialization signal line INL, and a reset control signal line Rst etc. mentioned later) 
     For example, the light-emitting element  20  is an organic light-emitting diode (OLED) or a quantum dot light-emitting diode (QLED), and the light-emitting element  20  emits red light, green light, blue light, or white light, etc. under a driving of a corresponding pixel circuit  10 . The voltage signal line may include one voltage signal line or a plurality of voltage signal lines. For example, as illustrated in  FIG.  1   , the voltage signal line includes at least one of the first power supply line PL 1 , the second power supply line PL 2 , the light-emitting control signal line EML, the initialization signal line INL and the reset control signal line Rst etc. The gate line GL is configured to supply a scan signal SCAN to the pixel circuit  10 . The data line DL is configured to supply a data signal DATA to the pixel circuit  10 . For example, one pixel PX includes a plurality of pixel units  101 . A pixel may include a plurality of pixel units that emit light of different colors. For example, one pixel includes a pixel unit emitting red light, a pixel unit emitting green light, and a pixel unit emitting blue light, but is not limited thereto. The number of pixel units included in a pixel and a light-emitting color of each pixel unit can be determined as required. 
     For example, the first power supply line PL 1  is configured to supply a first voltage signal ELVDD that is constant to the pixel circuit  10 , the second power supply line PL 2  is configured to supply a second voltage signal ELVSS that is constant to the pixel circuit  10 , and the first voltage signal ELVDD is greater than the second voltage signal ELVSS. The light-emitting control signal line EML is configured to supply a light-emitting control signal EM to the pixel circuit  10 . The initialization signal line INL is configured to supply an initialization signal Vint to the pixel circuit  10 , and the reset control signal line Rst is configured to supply a reset control signal RESET to the pixel circuit  10 . For example, the initialization signal Vint is a constant voltage signal, and its magnitude may be between the first voltage signal ELVDD and the second voltage signal ELVSS, but not limited to this. For example, the initialization signal Vint may be less than or equal to the second voltage signal ELVSS. 
     As illustrated in  FIG.  1    and  FIG.  2   , the pixel circuit  10  includes a driving transistor Td, a first transistor T 1 , a second transistor T 2 , a third transistor T 3 , a fourth transistor T 4 , and a storage capacitor Cst. As illustrated in  FIG.  1    and  FIG.  2   , the driving transistor Td is electrically connected with the light-emitting element  20  and outputs a driving current under a control of the scan signal SCAN, the data signal DATA, the first voltage signal ELVDD, the second voltage signal ELVSS and other signals to drive the light-emitting element  20  to emit light. For example, the first transistor T 1  is a data writing transistor, the second transistor T 2  is a threshold compensation transistor, the third transistor T 3  is a light-emitting control transistor, and the fourth transistor T 4  is a reset transistor. 
     For example, as illustrated in  FIG.  1   , a first electrode plate Ca of the storage capacitor Cst is connected with a gate electrode Td 0  of the driving transistor Td, a second electrode plate Cb of the storage capacitor Cst is connected with the first power supply line PL 1 , and a first electrode Td 1  of the driving transistor Td is connected with the first power supply line PL 1 . 
     For example, as illustrated in  FIG.  1   , a gate electrode T 10  of the first transistor T 1  is connected with the gate line GL, a first electrode T 11  of the first transistor T 1  is connected with the first electrode Td 1  of the driving transistor Td, and a second electrode T 12  the first transistor T 1  is connected with the data line DL. 
     For example, as illustrated in  FIG.  1   , a gate electrode T 20  of the second transistor T 2  is connected with the gate line GL, a first electrode T 21  of the second transistor T 2  is connected with the second electrode Td 2  of the driving transistor Td, a second electrode T 22  of the second transistor T 2  is connected with the gate electrode Td 0  of the driving transistor Td. 
     For example, as illustrated in  FIG.  1   , a gate electrode T 30  of the third transistor T 3  is connected with the light-emitting control signal line EML, a first electrode T 31  of the third transistor T 3  is connected with the second electrode Td 2  of the driving transistor Td, and a second electrode T 32  of the third transistor T 3  is connected with a first electrode  201  of the light-emitting element  20 . 
     For example, as illustrated in  FIG.  1   , a second electrode  202  of the light-emitting element  20  is connected with the second power supply line PL 2 . 
     For example, as illustrated in  FIG.  1   , a gate electrode T 40  of the fourth transistor T 4  is connected with the reset control signal line Rst, a first electrode T 41  of the fourth transistor T 4  is connected with a gate electrode Td 0  of the driving transistor Td, and a second electrode T 42  of the fourth transistor T 4  is connected with the initialization signal line INL. 
     For example, the first electrode  201  of the light-emitting element  20  is an anode, and the second electrode  202  of the light-emitting element  20  is a cathode, but not limited thereto. 
     It should be noted that, the transistors used in an embodiment of the present disclosure may all be thin film transistors or field effect transistors, or other switching components with the same characteristics. A source electrode and a drain electrode of the transistor used here may be symmetrical in structure, so the source electrode and the drain electrode of the transistor may be indistinguishable in structure. In an embodiment of the present disclosure, in order to distinguish two electrodes of the transistor except the gate electrode, it is directly described that one electrode is the first electrode and the other electrode is the second electrode, so the first electrode and the second electrode of all or part of the transistors of the embodiment of the present disclosure are interchangeable as required. For example, the first electrode of the transistor described in the embodiments of the present disclosure may be the source electrode, and the second electrode may be the drain electrode; or, the first electrode of the transistor may be the drain electrode, and the second electrode may be the source electrode. 
     In addition, transistors can be classified into N-type transistor and P-type transistor according to characteristics. The embodiments of the present disclosure are described with reference to the case where the transistors all adopt P-type transistors by way of example. Based on descriptions and teachings of the present disclosure, those of ordinary skill in the art can easily think of using N-type transistors for at least part of the transistors in the pixel circuit structure of the embodiments of the present disclosure without any creative work, that is, an implementation manner of using the N-type transistor or a combination of the N-type transistor and the P-type transistor. Therefore, these implementations are also within a protection scope of the present disclosure. 
     For example, as illustrated in  FIG.  2   , the display panel includes: a plurality of pixel units  101 .  FIG.  2    illustrates three pixel units  101 . The number of pixel units  101  included in the display panel is not limited to that illustrated in the figure, and can be set as required. For example, as illustrated in  FIG.  2   , the plurality of pixel units  101  include a first pixel unit  1011 , a second pixel unit  1012 , and a third pixel unit  1013 . 
     For example, the first pixel unit  1011  is configured to emit light of a first color, the second pixel unit  1012  is configured to emit light of a second color, and the third pixel unit  1013  is configured to emit light of a third color. For example, the first pixel unit  1011  includes the pixel unit  101  that emits blue light, the second pixel unit  1012  includes the pixel unit  101  that emits red light, and the third pixel unit  1013  includes the pixel unit  101  that emits green light, the embodiments of the present disclosure are described by taking this as an example. For example, as illustrated in  FIG.  2   , the pixel PX includes a first pixel unit  1011 , a second pixel unit  1012 , and a third pixel unit  1013 , but is not limited thereto. 
       FIG.  3 A  to  FIG.  3 I  are plan views of patterns of a single layer or a stacked layer in the display panel provided by an embodiment of the present disclosure.  FIG.  3 A  is a plan view of an active layer in the display panel provided by an embodiment of the present disclosure.  FIG.  3 B  is a plan view of an active layer in the display panel provided by an embodiment of the present disclosure.  FIG.  3 C  is a plan view of a first conductive layer in the display panel provided by an embodiment of the present disclosure.  FIG.  3 D  is a plan view of the active layer and the first conductive layer in the display panel provided by an embodiment of the present disclosure.  FIG.  3 E  is a plan view of a second conductive layer in the display panel provided by an embodiment of the present disclosure.  FIG.  3 F  is a plan view of a via hole penetrating at least one of a first insulating layer, a second insulating layer, and a third insulating layer in the display panel provided by the embodiment of the present disclosure.  FIG.  3 G  is a plan view of a third conductive layer in the display panel provided by an embodiment of the present disclosure.  FIG.  3 H  is a plan view of a via hole penetrating a fourth insulating layer in the display panel provided by an embodiment of the present disclosure.  FIG.  3 I  is a plan view of a first electrode layer in the display panel provided by an embodiment of the present disclosure.  FIG.  4    is a cross-sectional view taken along line A-B of  FIG.  2   .  FIG.  5    is a cross-sectional view taken along line E-F of  FIG.  2   . Film layers above a first electrode layer LY 5  (illustrated in  FIG.  3 I ) are omitted in  FIG.  2   . The display panel provided by the embodiments of the present disclosure will be described in detail below with reference to  FIG.  2    to  FIG.  5   . 
       FIG.  2    to  FIG.  3 I  illustrate a first direction X and a second direction Y, the first direction X intersects with the second direction Y. For example, the first direction X is perpendicular to the second direction Y.  FIG.  4    to  FIG.  5    illustrate a third direction Z, which is perpendicular to the first direction X and perpendicular to the second direction Y. For example, the first direction X and the second direction Y are both parallel with a main surface of the base substrate BS (as illustrated in  FIG.  2   ,  FIG.  4    to  FIG.  5   ), and the main surface of the base substrate BS is a surface on which film layers are formed. The third direction Z may be a direction perpendicular to the main surface. For example, the third direction Z is a thickness direction of the base substrate BS. 
       FIG.  3 A  illustrates an active layer LY 0 . As illustrated in  FIG.  3 A , the active layer LY 0  includes a channel T 13  of the first transistor T 1 , a channel T 23  of the second transistor T 2 , a channel T 33  of the third transistor T 3 , and a channel T 43  of the fourth transistor T 4 . 
     For example, as illustrated in  FIG.  3 A , the driving transistor Td of the pixel circuit  10  of the first pixel unit  1011  includes a first channel CNL 1 , and the driving transistor Td of the pixel circuit  10  of the second pixel unit  1012  includes a second channel CNL 2 . 
     For example, as illustrated in  FIG.  3 A , the driving transistor Td of the pixel circuit  10  of the third pixel unit  1013  includes a third channel CNL 3 . 
     For example, the active layer of each transistor may include a source electrode region, a drain electrode region, and a channel between the source electrode region and drain electrode region. For example, the channel has characteristics of a semiconductor; the source electrode region and the drain electrode region are on two sides of the channel, and can be doped with impurities, and therefore are conductive and can be used as the first electrode and second electrode of the transistor, respectively. One of the first electrode and the second electrode of the transistor is the source electrode, and the other one of the first electrode and the second electrode of the transistor is the drain electrode. 
     For example, the material of the semiconductor layer LY 0  may include oxide semiconductor, organic semiconductor or amorphous silicon, polysilicon and so on. For example, the oxide semiconductor includes metal oxide semiconductor (for example, indium gallium zinc oxide (IGZO)), the polysilicon includes low temperature polysilicon or high temperature polysilicon, which is not limited in the embodiment of the present disclosure. It should be noted that, the above-mentioned source region and drain region may be regions doped with n-type impurities or p-type impurities, which are not limited in the embodiments of the present disclosure. 
     For example, as illustrated in  FIG.  2    and  FIG.  3 A , the width-to-length ratio of the first channel CNL 1  is greater than the width-to-length ratio of the second channel CNL 2 , and the shape of the first channel CNL 1  is different from the shape of the second channel CNL 2 . 
     In the display panel provided by the present disclosure, the channels of the driving transistors of the pixel units that emit light of different colors adopt different shapes and different width-to-length ratios, which can compensate a difference between light-emitting efficiency and lifespan of the pixel units that emit light of different colors, and effectively improving a display uniformity and the lifespan of the display device. 
     In the display panel provided by the present disclosure, the driving transistors of the pixel circuits are provided with channels of different shapes, and the driving transistors adopt different width-to-length ratios, so as to compensate for a problem of light-emitting efficiency difference of the pixel units that emit light of different colors, and improve the display uniformity and the lifespan of the display device. 
     For example, in some embodiments, a width of the first channel CNL 1  is the same as a width of the second channel CNL 2 , and a length of the first channel CNL 1  is less than a length of the second channel CNL 2 . 
     For example, as illustrated in  FIG.  2    and  FIG.  3 A , the shape of the first channel CNL 1  includes a U-shape. For example, as illustrated in  FIG.  3 B , an opening of the U-shaped first channel CNL 1  faces upward. 
     For example, as illustrated in  FIG.  3 A , the first channel CNL 1  includes a first portion P 11 , a second portion P 12 , and a third portion P 13 . The first portion P 11 , the second portion P 12 , and the third portion P 13  are sequentially connected so as to form a U-shaped structure. As illustrated in  FIG.  3 A , the first channel CNL 1  further includes a fourth portion P 14  and a fifth portion P 15 , the fourth portion P 14  is connected with the first portion P 11 , and the fifth portion P 15  is connected with the third portion P 13 . As illustrated in  FIG.  3 A , the first portion P 11  and the third portion P 13  extend in the second direction Y, and the second portion P 12  extends in the first direction X. As illustrated in  FIG.  3 A , the fourth portion P 14  and the fifth portion P 15  both extend in the first direction X. 
     For example, the shape of the second channel CNL 2  includes a mirrored S shape, a serpentine shape, a square waveform, a zigzag shape, or a double U shape. 
     For example, as illustrated in  FIG.  3 B , the shape of the second channel CNL 2  includes a double U-shape, and the double U-shape includes a first U-shaped portion  021  and a second U-shaped portion  022 , and the first U-shaped portion  021  and the second U-shaped portion  022  share the same side S 2 , and opening directions of the first U-shaped portion  021  and the second U-shaped portion  022  are different. As illustrated in  FIG.  3 A , the opening direction of the first U-shaped portion  021  is leftward, and the opening direction of the second U-shaped portion  022  is rightward. For example, as illustrated in  FIG.  3 B , the opening directions of the first U-shaped portion  021  and the second U-shaped portion  022  of the second channel CNL 2  are different from the opening direction of the U-shaped first channel CNL 1 . 
     For example, as illustrated in  FIG.  3 A , the second channel CNL 2  includes a first portion P 21 , a second portion P 22 , a third portion P 23 , a fourth portion P 24 , and a fifth portion P 25  connected in sequence; the first portion P 21 , the third portion P 23 , and the fifth portion P 25  all extend in the first direction X; the second portion P 22  and the fourth portion P 24  both extend in the second direction Y. 
     For example, in some embodiments, the width-to-length ratio of the first channel CNL 1  is different from the width-to-length ratio of the third channel CNL 3 . 
     For example, in some embodiments, the width-to-length ratio of the first channel CNL 1 , the width-to-length ratio of the second channel CNL 2 , and the width-to-length ratio of the third channel CNL 3  are all different. 
     For example, in some embodiments, the width-to-length ratio of the second channel CNL 2  is greater than or equal to the width-to-length ratio of the third channel CNL 3 . 
     For example, as illustrated in  FIG.  3 A , the shape of the third channel CNL 3  is the same as the shape of the second channel CNL 2 . For example, the shape of the third channel CNL 3  also includes a mirror image of S-shape, a serpentine shape, a square waveform, a zigzag shape, or a double U-shape. 
     For example, as illustrated in  FIG.  3 B , the shape of the third channel CNL 3  includes the double U-shape, and the double U-shape includes a first U-shaped portion  031  and a second U-shaped portion  032 , and the first U-shaped portion  031  and the second U-shaped portion  031  share the same side S 3 , and the opening directions of the first U-shaped portion  031  and the second U-shaped portion  032  are different. As illustrated in  FIG.  3 A , the opening direction of the first U-shaped portion  031  is leftward, and the opening direction of the second U-shaped portion  032  is rightward. For example, as illustrated in  FIG.  3 B , the opening direction of the first U-shaped portion  031  and the second U-shaped portion  032  of the third channel CNL 3  are different from the opening direction of the U-shaped first channel CNL 1 . For example, as illustrated in  FIG.  3 B , the opening direction of the first U-shaped portion  021  of the second channel CNL 2  is the same as the opening direction of the first U-shaped portion  031  of the third channel CNL 3 , and the opening direction of the second U-shaped portion  022  of the second channel CNL 2  is the same as the opening direction of the second U-shaped portion  032  of the third channel CNL 3 . 
     For example, as illustrated in  FIG.  3 A , the third channel CNL 3  includes a first portion P 31 , a second portion P 32 , a third portion P 33 , a fourth portion P 34 , and a fifth portion P 35  that are connected in sequence; the first portion P 31 , the third portion P 33 , and the fifth portion P 35  all extend in the first direction X; the second portion P 32  and the fourth portion P 34  both extend in the second direction Y. 
     For example, in some embodiments, a width of the third channel CNL 3  is the same as a width of the second channel CNL 2 , and a length of the third channel CNL 3  is greater than or equal to a length of the second channel CNL 2 . Thus, the width-to-length ratio of the second channel CNL 2  is greater than or equal to the width-to-length ratio of the third channel CNL 3 . 
     As illustrated in  FIG.  3 D , the width of the first channel CNL 1  is w 1 , the width of the second channel CNL 2  is w 2 , and the width of the third channel CNL 3  is w 3 . In some embodiments, w 1 =w 2 =w 3 , but not limited thereto. In other embodiments, w 1 , w 2 , w 3  are different. In some embodiments, w 1  is greater than w 2  and greater than w 3 . In other embodiments, w 1  is greater than w 2 , and w 2 =w 3 . 
     As illustrated in  FIG.  3 A  and  FIG.  3 D , a length of the first portion P 11  of the first channel CNL 1  is L 11 , a length of the second portion P 12  of the first channel CNL 1  is L 12 , and a length of the third portion P 13  of the first channel CNL 1  is L 13 , then, the length of the first channel CNL 1  L 1 =L 11 +L 12 +L 13 +L 14 +L 15 . Therefore, the width-to-length ratio of the first channel CNL 1  is w 1 /L 1 . 
     As illustrated in  FIG.  3 A  and  FIG.  3 D , a length of the first portion P 21  of the second channel CNL 2  is L 21 , a length of the second portion P 22  of the second channel CNL 2  is L 22 , and a length of the third portion P 23  of the second channel CNL 2  is L 23 , a length of the fourth portion P 24  of the second channel CNL 2  is L 24 , and a length of the fifth portion P 25  of the second channel CNL 2  is L 25 , then, the length of the second channel CNL 2  L 2 =L 21 +L 22 +L 23 +L 24 +L 25 . Therefore, the width-to-length ratio of the second channel CNL 2  is w 2 /L 2 . 
     As illustrated in  FIG.  3 A  and  FIG.  3 D , a length of the first portion P 31  of the third channel CNL 3  is L 31 , a length of the second portion P 32  of the third channel CNL 3  is L 32 , a length of the third portion P 33  of the third channel CNL 3  is L 33 , a length of the fourth portion P 34  of the third channel CNL 3  is L 34 , and a length of the fifth portion P 35  of the third channel CNL 3  is L 35 , then, the length of the third channel CNL 3  L 3 =L 31 +L 32 +L 33 +L 34 +L 35 . Therefore, the width-to-length ratio of the third channel CNL 3  is w 2 /L 3 . 
     For example, in some embodiments, L 2 =L 3 , for further example, L 21 =L 31 , L 22 =L 32 , L 23 =L 33 , L 24 =L 34 , L 25 =L 35 . 
     For example, as illustrated in  FIG.  3 A  and  FIG.  3 D , the length L 21  of the first portion P 21  of the second channel CNL 2 , the length L 23  of the third portion P 23  of the second channel CNL 2 , and the length L 25  of the fifth portion P 25  of the second channel CNL 2  are all greater than the length L 11  of the first portion P 11  of the first channel CNL 1 , and are all greater than the length L 13  of the third portion P 13  of the first channel CNL 1 . For example, the length L 21 , the length L 23 , and the length L 25  are all greater than or equal to twice the length L 11 , and are all greater than or equal to twice the length L 13 . 
     For example, as illustrated in  FIG.  3 A  and  FIG.  3 D , the length L 31  of the first portion P 31  of the third channel CNL 3 , the length L 33  of the third portion P 33  of the third channel CNL 3 , the length L 35  of the fifth portion P 35  of the third channel CNL 3  are all greater than the length L 13  of the third portion P 13  of the first channel CNL 1 . For example, the length L 31 , the length L 33 , and the length L 35  are all greater than or equal to twice the length L 11 , and are all greater than or equal to twice the length L 13 . 
     For example, in some embodiments, w 1 =w 2 =w 3 , L 1 &lt;L 2 , L 1 &lt;L 3 , and L 2 =L 3 . 
     For example, in some embodiments, w 1 =w 2 =w 3 , L 1 &lt;L 2 , L 1 &lt;L 3 , and L 2 &lt;L 3 . 
     For example, in some embodiments, w 1 &gt;w 2 =w 3 , and L 1 &lt;L 2 =L 3 . 
     For example, in some embodiments, w 1 &gt;w 2 =w 3 , and L 1 &lt;L 2 &lt;L 3 . 
     For example, as illustrated in  FIG.  2   ,  FIG.  4    and  FIG.  5   , the display panel further includes a base substrate BS, and the pixel unit  101  is located on the base substrate BS. As illustrated in  FIG.  3 D , the driving transistor Td of the pixel circuit  10  of the first pixel unit  1011  includes a first gate electrode Td 01 , and the driving transistor Td of the pixel circuit  10  of the second pixel unit  1012  includes a second gate electrode Td 02 . An orthographic projection of the first gate electrode Td 01  on the base substrate partially overlaps with an orthographic projection of the first channel CNL 1  on the base substrate, and an orthographic projection of the second gate electrode Td 02  on the base substrate partially overlaps with an orthographic projection of the second channel CNL 2  on the base substrate. 
     For example, as illustrated in  FIG.  3 D , the driving transistor Td of the pixel circuit  10  of the third pixel unit  1013  includes a third gate electrode Td 03 , an orthographic projection of the third gate electrode Td 03  on the base substrate partially overlaps with an orthographic projection of the third channel CNL 3  on the base substrate. 
     For example, in some embodiments, a size of the first gate electrode Td 01  in the first direction X, a size of the second gate electrode Td 02  in the first direction X, and a size of the third gate electrode Td 03  in the first direction X are same. For example, in some embodiments, a size of the first gate electrode Td 01  in the second direction Y, a size of the second gate electrode Td 02  in the second direction Y, and a size of the third gate electrode Td 03  in the second direction Y are same. 
       FIG.  3 C  illustrates a first conductive layer LY 1 . The first conductive layer LY 1  includes the light-emitting control signal line EML, the gate line GL, the reset control signal line Rst, the initialization signal line INL, and the first electrode plate Ca of the storage capacitor Cst (the gate electrode Td 0  of the driving transistor Td). For example, as illustrated in  FIG.  3 C , the light-emitting control signal line EML, the gate line GL, the reset control signal line Rst, and the initialization signal line INL all extend in the first direction X and are arranged in the second direction Y. As illustrated in  FIG.  3 D , both the second transistor T 2  and the fourth transistor T 4  are dual-gate transistors. 
     For example, the light-emitting element  20  includes an organic light-emitting diode or a quantum dot light-emitting diode, and the display panel includes an organic light-emitting diode display panel or a quantum dot light-emitting diode display panel. In the pixel unit of the display panel, the driving transistor is connected with the light-emitting element, and outputs the driving current to the light-emitting element under the control of signals such as the data signal and the scan signal, thereby driving an organic light-emitting element to emit light. 
     It should be noted that, in the display panel provided by the embodiments of the present disclosure, the third pixel unit  1013  may not be provided in the pixel PX. 
       FIG.  3 E  illustrates a second conductive layer LY 2 . The second conductive layer LY 2  includes the second electrode plate Cb of the storage capacitor Cst. As illustrated in  FIG.  2   ,  FIG.  3 E  and  FIG.  4   , the second electrode plate Cb of the storage capacitor Cst includes an opening OPN. 
       FIG.  3 G  illustrates a third conductive layer LY 3 . The third conductive layer LY 3  includes the data line DL, the first power supply line PL 1 , a connection electrode CE 1 , a connection electrode CE 2 , and a connection electrode CE 3 . The connection electrode CE 1  may be referred to as a first connection electrode, the connection electrode CE 2  may be referred to as a second connection electrode, and the connection electrode CE 3  may be referred to as a third connection electrode. 
     As illustrated in  FIG.  4    and  FIG.  5   , the display panel includes a buffer layer BL, an active layer LY 0 , a first insulating layer ISL 1 , the first conductive layer LY 1 , a second insulating layer ISL 2 , the second conductive layer LY 2 , a third insulating layer ISL 3 , and a third conductive layer LY 3 . A fourth insulating layer ISL 4  is located on the third conductive layer LY 3 , and the first electrode  201  of the light-emitting element  20  is connected with the connection electrode CE 1  through a via hole V 9  penetrating the fourth insulating layer ISL 4 . The connection electrode CE 1  is connected with the second electrode T 32  of the third transistor T 3  through a via hole V 5 , which penetrates the first insulating layer ISL 1 , the second insulating layer ISL 2 , and the third insulating layer ISL 3 . As illustrated in  FIG.  3 H , the via hole V 9  penetrates the fourth insulating layer ISL 4 . 
       FIG.  3 F  illustrates via holes penetrating at least one of the first insulating layer ISL 1 , the second insulating layer ISL 2 , and the third insulating layer ISL 3 .  FIG.  3 F  illustrates via hole V 1 , via hole V 2 , via hole V 3 , via hole V 4 , via hole V 5 , via hole V 6 , via hole V 7 , and via hole V 8 . 
     Referring to  FIG.  2   ,  FIG.  3 F  and  FIG.  3 G , one end of the connection electrode CE 2  is connected with the first electrode plate Ca of the storage capacitor Cst (the gate electrode Td 0  of the driving transistor Td) through the via hole V 1 , and the other end of the connection electrode CE 2  is connected with the first electrode T 41  of the fourth transistor T 4  through the via hole V 2 . 
     As illustrated in  FIG.  2    and  FIG.  4   , the first power supply line PL 1  is connected with the second electrode plate Cb of the storage capacitor Cst through the via hole V 7  penetrating the third insulating layer ISL 3 , and the first electrode plate Ca of the storage capacitor Cst and the gate electrode Td 0  of the driving transistor Td are integrally formed, and are connected with one end of the connection electrode CE 2  (as illustrated in  FIG.  2    and  FIG.  3 G ) through the via hole V 1 , and the other end of the connection electrode CE 2  (as illustrated in  FIG.  2    and  FIG.  3 G ) is connected with the second electrode T 22  of the second transistor T 2  through the via hole V 2 . For example, the via hole V 1  penetrates the second insulating layer ISL 2  and the third insulating layer ISL 3 , and the via hole V 2  penetrates the first insulating layer ISL 1 , the second insulating layer ISL 2 , and the third insulating layer ISL 3 . 
     As illustrated in  FIG.  2   , the connection electrode CE 2  passes through the opening OPN and is connected with the gate electrode Td 0  of the driving transistor Td. 
     As illustrated in  FIG.  2   , one end of the connection electrode CE 3  is connected with the second electrode T 42  of the fourth transistor T 4  through the via hole V 3 , and the other end of the connection electrode CE 3  is connected with the initialization signal line INL through the via hole V 4 . For example, the via hole V 3  penetrates the first insulating layer ISL 1 , the second insulating layer ISL 2 , and the third insulating layer ISL 3 . For example, the via hole V 4  penetrates the second insulating layer ISL 2  and the third insulating layer ISL 3 . 
     As illustrated in  FIG.  2   , the data line DL is connected with the second electrode T 12  of the first transistor T 1  through the via hole V 8 . For example, the via hole V 8  penetrates the first insulating layer ISL 1 , the second insulating layer ISL 2 , and the third insulating layer ISL 3 . 
     As illustrated in  FIG.  2   , the first power supply line PL is connected with the second electrode plate Cb of the storage capacitor Cst through the via hole V 7 . The via hole V 7  penetrates the third insulating layer ISL 3 . 
     As illustrated in  FIG.  2   , the first power supply line PL is connected with the first electrode Td 1  of the driving transistor Td through the via hole V 6 . The via hole V 6  penetrates the first insulating layer ISL 1 , the second insulating layer ISL 2 , and the third insulating layer ISL 3 . 
     As illustrated in  FIG.  5   , the light-emitting element  20  further includes the second electrode  202  and a light-emitting layer  203  located between the first electrode  201  and the second electrode  202 . In pixel units that emit light of different colors, materials of the light-emitting layer  203  are different. 
       FIG.  3 B  illustrates a via hole V 11 , a via hole V 12 , a via hole V 13 , and a via hole V 14  penetrating the first insulating layer ISL 1 .  FIG.  3 F  illustrates the via hole V 5 , the via hole V 7 , a via hole V 23 , a via hole V 24 , and a via hole V 25  penetrating at least one of the first insulating layer ISL 1 , the second insulating layer ISL 2 , and the third insulating layer ISL 3 .  FIG.  3 H  illustrates the via hole V 9  penetrating the fourth insulating layer ISL 4 . 
     As illustrated in  FIG.  2   , a part of the light-emitting control signal line EML serves as the gate electrode of the third transistor T 3 , a part of the gate line GL serves as the gate electrode of the first transistor T 1 , a part of the gate line GL serves as the gate electrode of the second transistor T 2 , and a part of the reset control signal line Rst serves as the gate electrode of the fourth transistor T 4 . 
     For example, the base substrate BS, the buffer layer BF, the first insulating layer ISL 1 , the second insulating layer ISL 2 , the third insulating layer ISL 3 , and the fourth insulating layer ISL 4  are all made of insulating materials. For example, the base substrate BS includes a flexible material such as polyimide, but is not limited thereto. At least one of the buffer layer BF, the first insulating layer ISL 1 , the second insulating layer ISL 2 , the third insulating layer ISL 3 , and the fourth insulating layer ISL 4  is made of an inorganic insulating material or an organic insulating material. For example, the inorganic insulating material includes silicon oxide, silicon nitride, silicon oxynitride, etc., and the organic insulating material includes resin, but is not limited thereto. 
     For example, the first conductive layer LY 1 , the second conductive layer LY 2 , and the third conductive layer LY 3  are all made of metal materials. The first conductive layer LY 1 , the second conductive layer LY 2 , and the third conductive layer LY 3  can be made of the same material, or can be made of different materials, which can be determined as required. 
     In the embodiments of the present disclosure, patterns of each single layer and via holes may be formed by a patterning process. For example, forming a specific pattern includes forming a thin film, forming a photoresist pattern on the thin film, and patterning the thin film by using the photoresist pattern as a mask to form the specific pattern. The first conductive layer LY 1 , the second conductive layer LY 2 , the third conductive layer LY 3 , and the via holes in the insulating layer can all be formed by this method. For the active layer LY 0 , a semiconductor pattern can be formed first, the first insulating layer ISL 1  is formed on the semiconductor pattern, the first conductive layer LY 1  is formed on the first insulating layer ISL 1 , and the first conductive layer LY 1  is used as a mask for doping the semiconductor pattern to form the active layer LY 0  including the channel, the source region and the drain region on both sides of the channel. 
     It should be noted that the layout of the pixel units of the display panel provided by the embodiments of the present disclosure is not limited to that illustrated in  FIG.  2   , and other layout diagrams may be formed by transforming on the basis of  FIG.  2   . The above description is given with reference to the case where the pixel unit has 5T1C by way of example, but the embodiments of the present disclosure are not limited thereto. For example, each pixel unit  101  may include pixel circuits and light-emitting elements with circuit structures such as a 7T1C, an 8T2C, or a 4T1C in the art, the pixel circuit works under the control of the data signal transmitted through the data line, the gate electrode scan signal transmitted through the gate line, and the light-emitting control signal provided by the light-emitting control signal line to drive the light-emitting element to emit light, so as to realize operations such as display. 
     At least one embodiment of the present disclosure provides a display device including any one of the above-mentioned display panels. 
     For example, the display device may be an organic light-emitting diode display device. The display device may be any organic light-emitting diode display device such as any product or component with a display function, for example a TV, a digital camera, a mobile phone, a watch, a tablet computer, a notebook computer, a navigator and so on. 
     It should be noted that, for the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the thickness of a layer or region is exaggerated. It can be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” or “under” another element, the element can be “directly” “on” or “under” the other element, or there may be intermediate elements. 
     In the embodiments of the present disclosure, the patterning or patterning process may only include a photolithography process, or include a photolithography process and an etching process, or may include other processes for forming predetermined patterns such as printing process and inkjet process. The photolithography process refers to the process including film formation, exposure, development, etc., using photoresist, mask, exposure machine, etc. to form patterns. The corresponding patterning process can be selected according to the structure formed in the embodiment of the present disclosure. 
     The above are only specific implementations of the present disclosure, the protection scope of the present disclosure is not limited thereto. Any changes or substitutions easily occur to those skilled in the art within the technical scope of the present disclosure should be covered in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.