Patent Publication Number: US-2023165059-A1

Title: Display panel

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. application Ser. No. 17/764,479, filed Jun. 25, 2021, which a national stage application under 35 U.S.C. § 371 of International Application No. PCT/CN2021/102249, filed Jun. 25, 2021. Each of the forgoing applications is herein incorporated by reference in its entirety for all purposes. 
    
    
     TECHNICAL FIELD 
     The present invention relates to display technology, more particularly, to a display panel. 
     BACKGROUND 
     Organic Light Emitting Diode (OLED) display is one of the hotspots in the field of flat panel display research today. Unlike Thin Film Transistor-Liquid Crystal Display (TFT-LCD), which uses a stable voltage to control brightness, OLED is driven by a driving current required to be kept constant to control illumination. The OLED display panel includes a plurality of pixel units configured with pixel-driving circuits arranged in multiple rows and columns. Each pixel-driving circuit includes a driving transistor having a gate terminal connected to one gate line per row and a drain terminal connected to one data line per column. When the row in which the pixel unit is gated is turned on, the switching transistor connected to the driving transistor is turned on, and the data voltage is applied from the data line to the driving transistor via the switching transistor, so that the driving transistor outputs a current corresponding to the data voltage to an OLED device. The OLED device is driven to emit light of a corresponding brightness. 
     SUMMARY 
     In one aspect, the present disclosure provides a display panel, comprising a base substrate, a plurality of subpixels, a respective subpixel comprising a respective light emitting element and a respective pixel driving circuit; wherein the respective pixel driving circuit comprises a third transistor; and a storage capacitor comprising a first capacitor electrode in a first conductive layer and a second capacitor electrode in a second conductor layer; wherein the second conductive layer is on a side of the first conductive layer away from the base substrate; the second capacitor electrode comprises an extension extending away from an electrode main body of the second capacitor electrode; and an orthographic projection of the extension on the base substrate at least partially overlaps with an orthographic projection of an active layer of the third transistor of the respective pixel driving circuit on the base substrate. 
     Optionally, the third transistor comprises a first gate electrode and a second gate electrode; an orthographic projection of the first gate electrode on the base substrate overlaps with an orthographic projection of a first channel part of the active layer of the third transistor on the base substrate; an orthographic projection of the second gate electrode on the base substrate overlaps with an orthographic projection of a second channel part of the active layer of the third transistor on the base substrate; the active layer of the third transistor further comprises a portion connecting the first channel part and the second channel part; and the orthographic projection of the extension on a base substrate at least partially overlaps with an orthographic projection of the portion connecting the first channel part and the second channel part on the base substrate. 
     Optionally, the display panel further comprises a first signal line layer on a side of the storage capacitor away from the base substrate; wherein multiple second capacitor electrodes respectively from multiple pixel driving circuits are sequentially connected to each other along a first direction; the first signal line layer comprises a plurality of first high voltage signal lines respectively along a first direction; and a respective one of the plurality of first high voltage signal lines is connected to the second capacitor electrode. 
     Optionally, the extension comprises a first extension part along a second direction and a second extension part along a first direction; the first extension part connects the second extension part with the electrode main body of the second capacitor electrode; and an orthographic projection of the second extension part on the base substrate at least partially overlaps with the orthographic projection of the active layer of the third transistor of the respective pixel driving circuit on the base substrate. 
     Optionally, the second extension part comprises a shielding portion and a non-shielding portion; an orthographic projection of the shielding portion on the base substrate at least partially overlaps with the orthographic projection of the active layer of the third transistor of the respective pixel driving circuit on the base substrate; an orthographic projection of the non-shielding portion on the base substrate is non-overlapping with the orthographic projection of the active layer of the third transistor of the respective pixel driving circuit on the base substrate; and a line width of the shielding portion is greater than a line width of the non-shielding portion. 
     Optionally, the respective pixel driving circuit further comprises a driving transistor, and a node connecting line connecting a drain electrode of the third transistor with a gate electrode of the driving transistor; wherein the drain electrode of the third transistor is connected to the gate electrode of the driving transistor; a source electrode of the third transistor is connected to a drain electrode of the driving transistor; and an orthographic projection of the first extension part on a line extending along the second direction at least partially overlaps with an orthographic projection of the node connecting line on the line. 
     Optionally, the display panel further comprises a plurality of data lines; wherein the first extension part is between the node connecting line and a respective data line of the plurality of data lines. 
     Optionally, the display panel further comprises a plurality of gate lines; wherein a respective gate line of the plurality of gate lines comprises a plurality of metal blocks spaced apart from each other in a first conductive layer, and a metal line along a first direction in a first signal line layer, the metal line along the first direction being connected to the plurality of metal blocks through vias, respectively. 
     Optionally, a respective metal block of the plurality of metal blocks has a L shape; an orthographic projection of a first channel part of the active layer of the third transistor on the base substrate overlaps with an orthographic projection of a first metal portion of the respective metal block of the plurality of metal blocks on the base substrate; an orthographic projection of a second channel part of the active layer of the third transistor on the base substrate overlaps with an orthographic projection of a second metal portion of the respective metal block of the plurality of metal blocks on the base substrate; and the first metal portion and the second metal portion are a first gate electrode and a second gate electrode of the third transistor. 
     Optionally, the display panel further comprises a plurality of first reset signal lines respectively along a first direction in a semiconductor material layer; and a plurality of second reset signal lines respectively along a second direction in a second signal line layer; wherein the plurality of first reset signal lines respectively cross over the plurality of second reset signal lines; a respective one of the plurality of first reset signal lines is connected to at least multiple ones of the plurality of second reset signal lines through vias; and a respective one of the plurality of second reset signal lines is connected to at least multiple ones of the plurality of first reset signal lines through vias. 
     Optionally, the display panel further comprises a plurality of second low voltage signal lines respectively along a second direction in a second signal line layer; wherein the plurality of second low voltage signal lines are electrically connected to a cathode of a light emitting element. 
     Optionally, the display panel further comprises a plurality of first high voltage signal lines respectively extending along the first direction in a first signal line layer; a plurality of second high voltage signal lines respectively extending along a second direction in a second signal line layer; wherein the plurality of first high voltage signal lines respectively cross over the plurality of second high voltage signal lines; a respective one of the plurality of first high voltage signal lines is connected to at least multiple ones of the plurality of second high voltage signal lines through vias; and a respective one of the plurality of second high voltage signal lines is connected to at least multiple ones of the plurality of first high voltage signal lines through vias. 
     Optionally, a respective one of the plurality of first high voltage signal lines comprises a main body extending along a first direction; a first protrusion protruding away from the main body along a second direction, and a second protrusion protruding away from the first protrusion along the second direction; wherein the second protrusion connects to the main body through the first protrusion; and the second protrusion is a portion of the respective one of the plurality of second high voltage signal line where the respective one of the plurality of second high voltage signal line is connected to a respective one of the plurality of first high voltage signal lines through one or more vias. 
     Optionally, the respective pixel driving circuit further comprises a driving transistor, and a node connecting line connecting a drain electrode of the third transistor with a gate electrode of the driving transistor; wherein the drain electrode of the third transistor is connected to the gate electrode of the driving transistor; a source electrode of the third transistor is connected to a drain electrode of the driving transistor; and an orthographic projection of the respective one of the plurality of second high voltage signal lines on the base substrate covers an orthographic projection of the node connecting line on the base substrate. 
     Optionally, an orthographic projection of the respective one of the plurality of second high voltage signal lines on the base substrate at least partially overlaps with an orthographic projection of at least one gate electrode of the third transistor on the base substrate. 
     Optionally, the display panel comprises a plurality of light emitting elements; and an interconnected first voltage supply network configured to provide a first voltage signal to cathodes of the plurality of light emitting elements; wherein the interconnected first voltage supply network comprises signal lines in a display area of the display panel, the display area being at least partially surrounded by a peripheral area; the signal lines comprise a plurality of first signal lines in a first signal line layer and a plurality of second signal lines in a second signal line layer; the display panel further comprises a planarization layer between the first signal line layer and the second signal line layer; and the plurality of first signal lines are electrically connected to the plurality of second signal lines. 
     Optionally, the interconnected first voltage supply network comprises a plurality of first-first voltage signal lines respectively along a first direction; and a plurality of second-first voltage signal lines respectively along a second direction; wherein the plurality of first-first voltage signal lines respectively cross over the plurality of second-first voltage signal lines. 
     Optionally, the interconnected first voltage supply network comprises a first sub-network formed by the plurality of first-first voltage signal lines and a second sub-network formed by the plurality of second-first voltage signal lines. 
     Optionally, a respective one of the plurality of first-first voltage signal lines is connected to at least multiple ones of the plurality of second-first voltage signal lines; and a respective one of the plurality of second-first voltage signal lines is connected to at least multiple ones of the plurality of first-first voltage signal lines. 
     Optionally, the plurality of first-first voltage signal lines and the plurality of second-first voltage signal lines interconnect through first vias respectively extending through the planarization layer, at least some of the first vias being in the display area; a respective one of the plurality of first-first voltage signal lines is connected to at least multiple ones of the plurality of second-first voltage signal lines respectively through multiple first vias extending through the planarization layer; and a respective one of the plurality of second-first voltage signal lines is connected to at least multiple ones of the plurality of first-first voltage signal lines respectively through multiple first vias extending through the planarization layer. 
     In another aspect, the present disclosure provides a display panel, comprising a plurality of subpixels, a respective subpixel comprising a respective light emitting element and a respective pixel driving circuit; wherein the display panel comprises a plurality of light emitting elements; and an interconnected first voltage supply network configured to provide a first voltage signal to cathodes of the plurality of light emitting elements; wherein the interconnected first voltage supply network comprises signal lines in a display area of the display panel, the display area being at least partially surrounded by a peripheral area; the signal lines comprise a plurality of first signal lines in a first signal line layer and a plurality of second signal lines in a second signal line layer; the display panel further comprises a planarization layer between the first signal line layer and the second signal line layer; and the plurality of first signal lines are electrically connected to the plurality of second signal lines. 
     Optionally, the interconnected first voltage supply network comprises a plurality of first-first voltage signal lines respectively along a first direction; and a plurality of second-first voltage signal lines respectively along a second direction; wherein the plurality of first-first voltage signal lines respectively cross over the plurality of second-first voltage signal lines. 
     Optionally, the interconnected first voltage supply network comprises a first sub-network formed by the plurality of first-first voltage signal lines and a second sub-network formed by the plurality of second-first voltage signal lines. 
     Optionally, a respective one of the plurality of first-first voltage signal lines is connected to at least multiple ones of the plurality of second-first voltage signal lines; and a respective one of the plurality of second-first voltage signal lines is connected to at least multiple ones of the plurality of first-first voltage signal lines. 
     Optionally, the plurality of first-first voltage signal lines and the plurality of second-first voltage signal lines interconnect through first vias respectively extending through the planarization layer, at least some of the first vias being in the display area; a respective one of the plurality of first-first voltage signal lines is connected to at least multiple ones of the plurality of second-first voltage signal lines respectively through multiple first vias extending through the planarization layer; and a respective one of the plurality of second-first voltage signal lines is connected to at least multiple ones of the plurality of first-first voltage signal lines respectively through multiple first vias extending through the planarization layer. 
     Optionally, the display panel further comprises a gate-on-array circuit in a peripheral area of the display panel; wherein the interconnected first voltage supply network comprises a first peripheral first voltage line in the peripheral area on a first side of the display panel; and an orthographic projection of the first peripheral first voltage line on a base substrate at least partially overlaps with an orthographic projection of the gate-on-array circuit on the base substrate. 
     Optionally, the display panel further comprises an anode metal layer on a side of the first peripheral first voltage line away from the gate-on-array circuit; and a cathode layer on a side of the anode metal layer away from the first peripheral first voltage line; wherein the cathode layer is connected to the anode metal layer through one or more first peripheral vias in the peripheral area and extending through a third planarization layer, the anode metal layer is connected to the first peripheral first voltage line through one or more second peripheral vias in the peripheral area and extending through a second planarization layer, thereby providing the first voltage signal to the cathodes of the plurality of light emitting elements; the one or more first peripheral vias connecting the cathode layer and the anode metal layer, and the one or more second peripheral vias connecting the anode metal layer and the interconnected first voltage supply network are limited in the peripheral area, and absent in the display area; and the first peripheral first voltage line and the anode metal layer connected to the first peripheral first voltage line respectively partially surround a display area. 
     Optionally, the display panel further comprises an interconnected reset signal supply network configured to provide a reset signal to a plurality of pixel driving circuits; wherein the interconnected reset signal supply network comprises signal lines in a display area of the display panel. 
     Optionally, the interconnected reset signal supply network comprises a plurality of first reset signal lines respectively along a first direction; and a plurality of second reset signal lines respectively along a second direction; wherein the plurality of first reset signal lines respectively cross over the plurality of second reset signal lines. 
     Optionally, a respective one of the plurality of first reset signal lines is connected to at least multiple ones of the plurality of second reset signal lines; and a respective one of the plurality of second reset signal lines is connected to at least multiple ones of the plurality of first reset signal lines. 
     Optionally, a minimal distance between a respective second reset signal line of the plurality of second reset signal lines and a respective second-first voltage signal line of the plurality of second-first voltage signal lines that is most adjacent to the respective second reset signal line is less than a minimal distance between the respective second reset signal line and a respective data line of a plurality of data line that is most adjacent to the respective second reset signal line. 
     Optionally, a total of three data lines and a total of one second-first voltage signal line are between two most adjacent second reset signal lines of the plurality of second reset signal lines. 
     Optionally, the display panel comprises a base substrate; a semiconductor material layer on the base substrate; a planarization layer on a side of the semiconductor material layer away from the base substrate; a second signal line layer on a side of the planarization layer away from the semiconductor material layer; wherein the display panel further comprises an interconnected reset signal supply network configured to provide a reset signal to a plurality of pixel driving circuits; the interconnected reset signal supply network comprises a plurality of first reset signal lines respectively along a first direction and a plurality of second reset signal lines respectively along a second direction; and the semiconductor material layer comprises the plurality of first reset signal lines, and the second signal line layer comprises the plurality of second reset signal lines. 
     Optionally, the plurality of first reset signal lines and the plurality of second reset signal lines interconnect through second vias respectively extending through at least the planarization layer; wherein the display panel further comprises a gate insulating layer on a side of the semiconductor material layer away from the base substrate; an insulating layer on a side of the gate insulating layer away from the semiconductor material layer; and an inter-layer dielectric layer a side of the insulating layer away from the gate insulating layer; wherein the planarization layer is on a side of the inter-layer dielectric layer away from the insulating layer; and the plurality of first reset signal lines and the plurality of second reset signal lines interconnect through second vias, a respective second via extending through the planarization layer, the inter-layer dielectric layer, the insulating layer, and the gate insulating layer. 
     Optionally, a respective one of the plurality of first reset signal lines is connected to at least multiple ones of the plurality of second reset signal lines respectively through multiple second vias extending through at least the planarization layer; and a respective one of the plurality of second reset signal lines is connected to at least multiple ones of the plurality of first reset signal lines respectively through multiple second vias extending through at least the planarization layer. 
     Optionally, the plurality of first reset signal lines comprise a semiconductor material; the plurality of second reset signal lines comprise a metallic material; and the plurality of first reset signal lines and at least active layers of a plurality of thin film transistors are in the semiconductor material layer, and comprise a same semiconductor material. 
     Optionally, the display panel further comprises an interconnected second voltage supply network configured to provide a second voltage signal to a plurality of pixel driving circuits; wherein the interconnected second voltage supply network comprises a plurality of first-second voltage signal lines respectively along a first direction; and a plurality of second-second voltage signal lines respectively along a second direction; wherein the plurality of first-second voltage signal lines respectively cross over the plurality of second-second voltage signal lines. 
     Optionally, a respective one of the plurality of first-second voltage signal lines is connected to at least multiple ones of the plurality of second-second voltage signal lines; and a respective one of the plurality of second-second voltage signal lines is connected to at least multiple ones of the plurality of first-second voltage signal lines. 
     Optionally, the display panel comprises a base substrate; a first signal line layer on the base substrate; a planarization layer on a side of the first signal line layer away from the base substrate; a second signal line layer on a side of the planarization layer away from the first signal line layer; wherein the interconnected second voltage supply network comprises a plurality of first-second voltage signal lines respectively along a first direction and a plurality of second-second voltage signal lines respectively along a second direction; wherein the first signal line layer comprises the plurality of first-second voltage signal lines, and the second signal line layer comprises the plurality of second-second voltage signal lines. 
     Optionally, the plurality of first-second voltage signal lines and the plurality of second-second voltage signal lines interconnect through third vias respectively extending through the planarization layer; a respective one of the plurality of first-second voltage signal lines is connected to at least multiple ones of the plurality of second-second voltage signal lines respectively through multiple third vias extending through the planarization layer; and a respective one of the plurality of second-second voltage signal lines is connected to at least multiple ones of the plurality of first-second voltage signal lines respectively through multiple third vias extending through the planarization layer. 
     Optionally, a respective one of a plurality of first-second voltage signal lines comprises a main body extending along a first direction; a first protrusion protruding away from the main body along a second direction, and a second protrusion protruding away from the first protrusion along the second direction; wherein the second protrusion connects to the main body through the first protrusion; the first protrusion is a portion of the respective one of the plurality of first-second voltage signal lines where the respective one of a plurality of first-second voltage signal lines connects to a second capacitor electrode; and the second protrusion is a portion of the respective one of the plurality of first-second voltage signal lines where the respective one of the plurality of first-second voltage signal lines connects to a source electrode of a fourth transistor of a respective pixel driving circuit, a drain electrode of the fourth transistor being connected to a source electrode of a driving transistor. 
     Optionally, the display panel further comprises a plurality of second-second voltage signal lines at least partially in the display area; and a peripheral second voltage signal line in the peripheral area on a second side of the display panel; wherein the interconnected first voltage supply network comprises a plurality of first-first voltage signal lines and a plurality of second-first voltage signal lines at least partially in the display area; and a second peripheral first voltage signal line and a third peripheral first voltage signal line in the peripheral area on the second side of the display panel; wherein one or more of the plurality of second-second voltage signal lines are connected to the peripheral second voltage signal line; one or more of the plurality of second-first voltage signal lines are connected to the second peripheral first voltage signal line; the second peripheral first voltage signal line and the third peripheral first voltage signal line are connected to each other through a plurality of bridges; the plurality of first-first voltage signal lines, the peripheral second voltage signal line, and the plurality of bridges are in a first signal line layer; the plurality of second-second voltage signal lines, the second peripheral first voltage signal line are in a second signal line layer; and the third peripheral first voltage signal line comprise a first sub-layer in the first signal line layer and a second sub-layer in the second signal line layer. 
     Optionally, the display panel further comprises a plurality of gate lines; wherein a respective gate line of the plurality of gate lines comprises a plurality of metal blocks spaced apart from each other in a first conductive layer, and a metal line along a first direction in the first signal line layer, the signal line along the first direction being connected to the plurality of metal blocks, respectively. 
     Optionally, the display panel further comprises a plurality of first reset control signal line and a plurality of second reset control signal lines; a respective first reset control signal line and a respective second reset control signal line are respectively configured to reset a gate electrode of a driving transistor and an anode of a respective light emitting element; the respective first reset control signal line comprises a plurality of first metal blocks spaced apart from each other in a first conductive layer, and a first metal line along a first direction in the first signal line layer, the first metal line along the first direction being connected to the plurality of first metal blocks, respectively; and the respective second reset control signal line comprises a plurality of second metal blocks spaced apart from each other in the first conductive layer, and a second metal line along the first direction in the first signal line layer, the second metal line along the first direction being connected to the plurality of second metal blocks, respectively. 
     Optionally, a respective first-first voltage signal line of a plurality of first-first voltage signal lines comprises a first linear portion, a second linear portion, and a connecting portion connecting the first linear portion and the second linear portion; a virtual extension of the first linear portion crosses over the plurality of first metal blocks of the respective first reset control signal line; and an orthographic projection of the second linear portion on a base substrate is spaced apart from orthographic projections the plurality of first metal blocks on the base substrate. 
     Optionally, the display panel further comprises a second capacitor electrode of a storage capacitor in a second conductive layer; the second capacitor electrode comprises an extension extending away from an electrode main body of the second capacitor electrode; an orthographic projection of the extension on a base substrate at least partially overlaps with an orthographic projection of an active layer of a third transistor of the respective pixel driving circuit on the base substrate; and a portion of the extension is between a first node of the respective pixel driving circuit and a respective data line, configured to prevent interference from signals passing through the respective data line to the first node, the first node being configured to have a same voltage level as a gate electrode of a driving transistor. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The following drawings are merely examples for illustrative purposes according to various disclosed embodiments and are not intended to limit the scope of the present invention. 
         FIG.  1    is a schematic diagram illustrating the structure of a display panel in some embodiments according to the present disclosure. 
         FIG.  2    is a plan view of a display panel in some embodiments according to the present disclosure. 
         FIG.  3    is a circuit diagram illustrating the structure of a pixel driving circuit in some embodiments according to the present disclosure. 
         FIG.  4 A  is a diagram illustrating the structure of three pixel driving circuits for driving light emission of three light emitting elements of a display panel in some embodiments according to the present disclosure. 
         FIG.  4 B  is a diagram illustrating the structure of a semiconductor material layer in a display panel depicted in  FIG.  4 A . 
         FIG.  4 C  is a diagram illustrating the structure of a first conductive layer in a display panel depicted in  FIG.  4 A . 
         FIG.  4 D  is a diagram illustrating the structure of a second conductive layer in a display panel depicted in  FIG.  4 A . 
         FIG.  4 E  is a diagram illustrating the structure of a first signal line layer in a display panel depicted in  FIG.  4 A . 
         FIG.  4 F  is a diagram illustrating the structure of a second signal line layer in a display panel depicted in  FIG.  4 A . 
         FIG.  4 G  is a diagram illustrating the structure of a respective one of a plurality of first high voltage signal lines in some embodiments according to the present disclosure. 
         FIG.  4 H  is a diagram illustrating the layout of anodes of light emitting elements with respect to pixel driving circuits of a display panel in some embodiments according to the present disclosure. 
         FIG.  4 I  is a diagram illustrating the structure of anodes, a first signal line layer, and a second signal line layer in a display panel in some embodiments according to the present disclosure. 
         FIG.  4 J  is a diagram illustrating a relative position between a respective one of a plurality of first low voltage signal lines and a plurality of first metal blocks of a respective first reset control signal line in some embodiments according to the present disclosure. 
         FIG.  5 A  is a cross-sectional view along an A-A′ line in  FIG.  4 A . 
         FIG.  5 B  is a cross-sectional view along a B-B′ line in  FIG.  4 A . 
         FIG.  5 C  is a cross-sectional view along a C-C′ line in  FIG.  4 A . 
         FIG.  5 D  is a cross-sectional view along a D-D′ line in  FIG.  4 A . 
         FIG.  5 E  is a cross-sectional view along a E-E′ line in  FIG.  4 A . 
         FIG.  6 A  is a diagram illustrating the structure of an interconnected low voltage supply network, an interconnected reset signal supply network, and an interconnected high voltage supply network in a display panel in some embodiments according to the present disclosure. 
         FIG.  6 B  is a diagram illustrating the structure of an interconnected low voltage supply network in a display panel in some embodiments according to the present disclosure. 
         FIG.  6 C  is a diagram illustrating the structure of an interconnected reset signal supply network in a display panel in some embodiments according to the present disclosure. 
         FIG.  6 D  is a diagram illustrating the structure of an interconnected high voltage supply network in a display panel in some embodiments according to the present disclosure. 
         FIG.  7 A  is a schematic diagram illustrating the structure in a first region ZR 1  in  FIG.  1   . 
         FIG.  7 B  is a diagram illustrating the structure of a first signal line layer in a first region ZR 1  depicted in  FIG.  7 A . 
         FIG.  7 C  is a diagram illustrating the structure of a second signal line layer in a first region ZR 1  depicted in  FIG.  7 A . 
         FIG.  7 D  is a diagram illustrating the structure of a second planarization layer in a first region ZR 1  depicted in  FIG.  7 A . 
         FIG.  7 E  is a diagram illustrating the structure of an anode layer in a first region ZR 1  depicted in  FIG.  7 A . 
         FIG.  7 F  is a diagram illustrating the structure of a third planarization layer in a first region ZR 1  depicted in  FIG.  7 A . 
         FIG.  7 G  is a diagram illustrating the structure of a cathode layer in a first region ZR 1  depicted in  FIG.  7 A . 
         FIG.  8    is a cross-sectional view along an F-F′ line in  FIG.  7 A . 
         FIG.  9 A  shows an IR drop in a display panel in some embodiments according to the present disclosure. 
         FIG.  9 B  shows an IR drop in a related display panel without an interconnected low voltage supply network. 
         FIG.  10 A  is a schematic diagram illustrating the structure in a second zoom-in region ZR 2  in  FIG.  1   . 
         FIG.  10 B  is a schematic diagram illustrating the structure of low voltage signal lines in  FIG.  10 A . 
         FIG.  10 C  is a schematic diagram illustrating the structure of high voltage signal lines in  FIG.  10 A . 
         FIG.  10 D  is a schematic diagram illustrating the structure of reset signal lines in  FIG.  10 A . 
         FIG.  11 A  is a diagram illustrating the structure of a first sub-network of an interconnected low voltage supply network in some embodiments according to the present disclosure. 
         FIG.  11 B  is a diagram illustrating the structure of a second sub-network of an interconnected low voltage supply network in some embodiments according to the present disclosure. 
         FIG.  11 C  is a diagram illustrating the structure of an interconnected low voltage supply network comprising a first sub-network and a second sub-network in some embodiments according to the present disclosure. 
         FIG.  12 A  is a diagram illustrating the structure of a plurality of first low voltage signal lines of an interconnected low voltage supply network in some embodiments according to the present disclosure. 
         FIG.  12 B  is a diagram illustrating the structure of a sub-network of a plurality of second low voltage signal lines of an interconnected low voltage supply network in some embodiments according to the present disclosure. 
         FIG.  12 C  is a diagram illustrating the structure of an interconnected low voltage supply network comprising a plurality of first low voltage signal lines and a sub-network of a plurality of second low voltage signal lines in some embodiments according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The disclosure will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of some embodiments are presented herein for purpose of illustration and description only. It is not intended to be exhaustive or to be limited to the precise form disclosed. 
     The present disclosure provides, inter alia, a display panel that substantially obviate one or more of the problems due to limitations and disadvantages of the related art. In one aspect, the present disclosure provides a display panel including a plurality of subpixels. A respective subpixel includes a respective light emitting element and a respective pixel driving circuit. In some embodiments, the display panel includes a plurality of light emitting elements and an interconnected first voltage supply network configured to provide a first voltage signal to cathodes of the plurality of light emitting elements. Optionally, the interconnected first voltage supply network includes signal lines in a display area of the display panel. The display area is at least partially surrounded by a peripheral area. The signal lines include a plurality of first signal lines in a first signal line layer and a plurality of second signal lines in a second signal line layer. The display panel further includes a planarization layer between the first signal line layer and the second signal line layer. The plurality of first signal lines are electrically connected to the plurality of second signal lines. In one example, a first voltage signal line is a low voltage signal line, and a second voltage signal line is a high voltage signal line. 
     As used herein, the term “display area” refers to an area of the display panel where an image is actually displayed. Optionally, the display area may include both a subpixel region and an inter-subpixel region. A subpixel region refers to a light emission region of a subpixel, such as a region corresponding to a pixel electrode in a liquid crystal display or a region corresponding to a light emissive layer in an organic light emitting display. An inter-subpixel region refers to a region between adjacent subpixel regions, such as a region corresponding to a black matrix in a liquid crystal display or a region corresponding a pixel definition layer in an organic light emitting display. Optionally, the inter-subpixel region is a region between adjacent subpixel regions in a same pixel. Optionally, the inter-subpixel region is a region between two adjacent subpixel regions from two adjacent pixels. 
     As used herein the term “peripheral area” refers to an area of a display panel where various circuits and wires are provided to transmit signals to the display substrate. To increase the transparency of the display panel, non-transparent or opaque components of the display panel (e.g., battery, printed circuit board, metal frame), can be disposed in the peripheral area rather than in the display areas. 
     Various appropriate light emitting elements may be used in the present display panel. Examples of appropriate light emitting elements include organic light emitting diodes, quantum dots light emitting diodes, and micro light emitting diodes. Optionally, the light emitting element is micro light emitting diode. Optionally, the light emitting element is an organic light emitting diode including an organic light emitting layer. 
       FIG.  1    is a schematic diagram illustrating the structure of a display panel in some embodiments according to the present disclosure. Referring to  FIG.  1   , the display panel in some embodiments includes an interconnected low voltage supply network VSSN. The interconnected low voltage supply network VSSN is configured to provide a low voltage signal to cathodes of the plurality of light emitting elements. The interconnected low voltage supply network VSSN includes signal lines in a display area DA of the display panel. The display panel further includes one or more integrated circuits (e.g., IC 1 , IC 2 , IC 3 , and IC 4 ) in a peripheral area PA. The display panel further includes one or more high voltage signal line VDD, one or more reset signal line VIN, and a gate-on-array circuit GOA. 
     In some embodiments, the interconnected low voltage supply network VSSN includes a plurality of first low voltage signal lines Vss 1  respectively along a first direction DR 1 ; and a plurality of second low voltage signal lines Vss 2  respectively along a second direction DR 2 . The first direction DR 1  and the second direction DR 2  are different from each other. The plurality of first low voltage signal lines Vss 1  respectively cross over the plurality of second low voltage signal lines Vss 2 . 
       FIG.  2    is a plan view of a display panel in some embodiments according to the present disclosure. Referring to  FIG.  2   , the display panel includes an array of subpixels Sp. Each subpixel includes an electronic component, e.g., a light emitting element. In one example, the light emitting element is driven by a respective pixel driving circuit PDC. The display panel includes a plurality of gate lines GL, a plurality of data lines DL, and a plurality of high voltage signal lines Vdd. Light emission in a respective subpixel is driven by a respective pixel driving circuit PDC. In one example, a high voltage signal is input, through a respective one of the plurality of high voltage signal lines Vdd, to the respective pixel driving circuit PDC connected to an anode of the light emitting element; a low voltage signal is input to a cathode of the light emitting element. A voltage difference between the high voltage signal (e.g., the VDD signal) and the low voltage signal (e.g., the VSS signal) is a driving voltage ΔV that drives light emission in the light emitting element. 
     The display panel in some embodiments includes a plurality of subpixels. In some embodiments, the plurality of subpixels includes a respective first subpixel, a respective second subpixel, a respective third subpixel, and a respective fourth subpixel. Optionally, a respective pixel of the display panel includes the respective first subpixel, the respective second subpixel, the respective third subpixel, and the respective fourth subpixel. The plurality of subpixels in the display panel are arranged in an array. In one example, the array of the plurality of subpixels includes a S 1 -S 2 -S 3 -S 4  format repeating array, in which S 1  stands for the respective first subpixel, S 2  stands for the respective second subpixel, S 3  stands for the respective third subpixel, and S 4  stands for the respective fourth subpixel. In another example, the S 1 -S 2 -S 3 -S 4  format is a C 1 -C 2 -C 3 -C 4  format, in which C 1  stands for the respective first subpixel of a first color, C 2  stands for the respective second subpixel of a second color, C 3  stands for the respective third subpixel of a third color, and C 4  stands for the respective fourth subpixel of a fourth color. In another example, the S 1 -S 2 -S 3 -S 4  format is a C 1 -C 2 -C 3 -C 2 ′ format, in which C 1  stands for the respective first subpixel of a first color, C 2  stands for the respective second subpixel of a second color, C 3  stands for the respective third subpixel of a third color, and C 2 ′ stands for the respective fourth subpixel of the second color. In another example, the C 1 -C 2 -C 3 -C 2 ′ format is a R-G-B-G format, in which the respective first subpixel is a red subpixel, the respective second subpixel is a green subpixel, the respective third subpixel is a blue subpixel, and the respective fourth subpixel is a green subpixel. 
     In some embodiments, a minimum repeating unit of the plurality of subpixels of the display panel includes the respective first subpixel, the respective second subpixel, the respective third subpixel, and the respective fourth subpixel. Optionally, each of the respective first subpixel, the respective second subpixel, the respective third subpixel, and the respective fourth subpixel, includes the first transistor T 1 , the second transistor T 2 , the third transistor T 3 , the fourth transistor T 4 , the fifth transistor T 5 , the sixth transistor T 6 , and the driving transistor Td. 
     Various appropriate pixel driving circuits may be used in the present display panel. Examples of appropriate driving circuits include 3T1C, 2T1C, 4T1C, 4T2C, 5T2C, 6T1C, 7T1C, 7T2C, 8T1C, and 8T2C. In some embodiments, the respective one of the plurality of pixel driving circuits is an 7T1C driving circuit. Various appropriate light emitting elements may be used in the present display panel. Examples of appropriate light emitting elements include organic light emitting diodes, quantum dots light emitting diodes, and micro light emitting diodes. Optionally, the light emitting element is micro light emitting diode. Optionally, the light emitting element is an organic light emitting diode including an organic light emitting layer. 
       FIG.  3    is a circuit diagram illustrating the structure of a pixel driving circuit in some embodiments according to the present disclosure. Referring to  FIG.  3   , in some embodiments, the respective pixel driving circuit includes a driving transistor Td; a storage capacitor Cst having a first capacitor electrode Ce 1  and a second capacitor electrode Ce 2 ; a first transistor T 1  having a gate electrode connected to a respective first reset control signal line of a plurality of first reset control signal line rst 1 , a source electrode connected to a respective reset signal line VintN in a present stage of a plurality of reset signal line, and a drain electrode connected to a first capacitor electrode Ce 1  of the storage capacitor Cst and a gate electrode of the driving transistor Td; a second transistor T 2  having a gate electrode connected to a respective gate line of a plurality of gate lines GL, a source electrode connected to a respective data line of a plurality of data lines DL, and a drain electrode connected to a source electrode of the driving transistor Td; a third transistor T 3  having a gate electrode connected to the respective gate line, a source electrode connected to the first capacitor electrode Ce 1  of the storage capacitor Cst and the gate electrode of the driving transistor Td, and a drain electrode connected to a drain electrode of the driving transistor Td; a fourth transistor T 4  having a gate electrode connected to a respective light emitting control signal line of a plurality of light emitting control signal lines em, a source electrode connected to a respective voltage supply line of a plurality of high voltage signal lines Vdd, and a drain electrode connected to the source electrode of the driving transistor Td and the drain electrode of the second transistor T 2 ; a fifth transistor T 5  having a gate electrode connected to the respective light emitting control signal line, a source electrode connected to drain electrodes of the driving transistor Td and the third transistor T 3 , and a drain electrode connected to an anode of a light emitting element LE; and a sixth transistor T 6  having a gate electrode connected to a respective second reset control signal line of a plurality of second reset control signal lines rst 2 , a source electrode connected to a reset signal line Vint(N+1) in the next adjacent stage of the plurality of reset signal line, and a drain electrode connected to the drain electrode of the fifth transistor and the anode of the light emitting element LE. The second capacitor electrode Ce 2  is connected to the respective voltage supply line and the source electrode of the fourth transistor T 4 . 
     Referring to  FIG.  3   , in some embodiments, the third transistor T 3  is a “double gate” transistor, and the first transistor T 1  is a “double gate” transistor. Optionally, in a “double gate” first transistor, the active layer of the first transistor crosses over a respective reset control signal lines twice (alternatively, the respective reset control signal line crosses over the active layer of the first transistor T 1  twice). Similarly, in a “double gate” third transistor, the active layer of the third transistor T 3  crosses over a respective gate line of the plurality of gate lines GL twice (alternatively, the respective gate line crosses over the active layer of the third transistor T 3  twice). 
     The pixel driving circuit further include a first node N 1 , a second node N 2 , a third node N 3 , and a fourth node N 4 . The first node N 1  is connected to the gate electrode of the driving transistor Td, the first capacitor electrode Ce 1 , and the source electrode of the third transistor T 3 . The second node N 2  is connected to the drain electrode of the fourth transistor T 4 , the drain electrode of the second transistor T 2 , and the source electrode of the driving transistor Td. The third node N 3  is connected to the drain electrode of the driving transistor Td, the drain electrode of the third transistor T 3 , and the source electrode of the fifth transistor T 5 . The fourth node N 4  is connected to the drain electrode of the fifth transistor T 5 , the drain electrode of the sixth transistor T 6 , the drain electrode of the sensing transistor Ts, and the anode of the light emitting element LE. 
       FIG.  4 A  is a diagram illustrating the structure of three pixel driving circuits for driving light emission of three light emitting elements of a display panel in some embodiments according to the present disclosure. Referring to  FIG.  4 A , the display panel in some embodiments includes a plurality of gate lines GL respectively extending along a first direction DR 1 , a plurality of data lines DL respectively extending along a second direction DR 2 ; a plurality of first high voltage signal lines Vdd 1  respectively extending along the first direction DR 1 ; a plurality of second high voltage signal lines Vdd 2  respectively extending along the second direction DR 2 ; a plurality of first low voltage signal lines Vss 1  respectively extending along the first direction DR 1 ; a plurality of second low voltage signal lines Vss 2  respectively extending along the second direction DR 2 ; a plurality of first reset signal lines Vint 1  respectively extending along the first direction DR 1 ; and a plurality of second reset signal lines Vint 2  respectively extending along the second direction DR 2 . The plurality of first low voltage signal lines Vss 1  respectively cross over the plurality of second low voltage signal lines Vss 2 . The plurality of first reset signal lines Vint 1  respectively cross over the plurality of second reset signal lines Vint 2 . The plurality of first high voltage signal lines Vdd 1  respectively cross over the plurality of second high voltage signal lines Vdd 2 . Optionally, the display panel further includes a plurality of first reset control signal lines rst 1  respectively extending along the first direction DR 1 ; a plurality of second reset control signal lines rst 2  respectively extending along the first direction DR 1 ; and a plurality of light emitting control signal lines em respectively extending along the first direction DR 1 . Corresponding positions of the plurality of transistors in a respective pixel driving circuit are PDC depicted in  FIG.  4 A . The respective pixel driving circuit PDC includes the first transistor T 1 , the second transistor T 2 , the third transistor T 3 , the fourth transistor T 4 , the fifth transistor T 5 , the sixth transistor T 6 , the sensing transistor Ts, and the driving transistor Td. 
       FIG.  4 B  is a diagram illustrating the structure of a semiconductor material layer in a display panel depicted in  FIG.  4 A .  FIG.  4 C  is a diagram illustrating the structure of a first conductive layer in a display panel depicted in  FIG.  4 A .  FIG.  4 D  is a diagram illustrating the structure of a second conductive layer in a display panel depicted in  FIG.  4 A .  FIG.  4 E  is a diagram illustrating the structure of a first signal line layer in a display panel depicted in  FIG.  4 A .  FIG.  3 F  is a diagram illustrating the structure of a second signal line layer in a display panel depicted in  FIG.  4 A .  FIG.  5 A  is a cross-sectional view along an A-A′ line in  FIG.  4 A . Referring to  FIG.  4 A  to  FIG.  4 F , and  FIG.  5 A , in some embodiments, the display panel includes a base substrate BS, a semiconductor material layer SML on the base substrate BS, a gate insulating layer GI on a side of the semiconductor material layer SML away from the base substrate BS, a first conductive layer CT 1  on a side of the gate insulating layer GI away from the semiconductor material layer SML, an insulating layer IN on a side of the first conductive layer away from the gate insulating layer GI, a second conductive layer CT 2  on a side of the insulating layer IN away from the first conductive layer CT 1 , an inter-layer dielectric layer ILD on a side of the second conductive layer CT 2  away from the insulating layer IN, a first signal line layer SL 1  on a side of the inter-layer dielectric layer ILD away from the second conductive layer CT 2 , a planarization layer PLN on a side of the first signal line layer SL 1  away from the inter-layer dielectric layer ILD, and a second signal line layer SL 2  on a side of the planarization layer PLN 1  away from the first signal line layer SL 1 . 
     Referring to  FIG.  3   ,  FIG.  4 A , and  FIG.  4 B , in some embodiments, the semiconductor material layer has a unitary structure. In  FIG.  4 B , the respective pixel driving circuit is annotated with labels indicating regions corresponding to the plurality of transistors in the respective pixel driving circuit, including the first transistor T 1 , the second transistor T 2 , the third transistor T 3 , the fourth transistor T 4 , the fifth transistor T 5 , the sixth transistor T 6 , and the driving transistor Td. The respective pixel driving circuit is further annotated with labels indicating components of each of the plurality of transistors in the pixel driving circuit. For example, the first transistor T 1  includes an active layer ACT 1 , a source electrode S 1 , and a drain electrode D 1 . The second transistor T 2  includes an active layer ACT 2 , a source electrode S 2 , and a drain electrode D 2 . The third transistor T 3  includes an active layer ACT 3 , a source electrode S 3 , and a drain electrode D 3 . The fourth transistor T 4  includes an active layer ACT 4 , a source electrode S 4 , and a drain electrode D 4 . The fifth transistor T 5  includes an active layer ACT 5 , a source electrode S 5 , and a drain electrode D 5 . The sixth transistor T 6  includes an active layer ACT 6 , a source electrode S 6 , and a drain electrode D 6 . The driving transistor Td includes an active layer ACTd, a source electrode Sd, and a drain electrode Dd. In one example, the active layers (ACT 1 , ACT 2 , ACT 3 , ACT 4 , ACT 5 , ACT 6 , and ACTd) of the transistors (T 1 , T 2 , T 3 , T 4 , T 5 , T 6 , and Td) in the respective pixel driving circuit are parts of a unitary structure. In another example, the active layers (ACT 1 , ACT 2 , ACT 3 , ACT 4 , ACT 5 , ACT 6 , and ACTd), the source electrodes (S 1 , S 2 , S 3 , S 4 , S 5 , S 6 , and Sd), and the drain electrodes (D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , and Dd) of the transistors (T 1 , T 2 , T 3 , T 4 , T 5 , T 6 , and Td) in the respective pixel driving circuit are parts of a unitary structure. In another example, the active layers (ACT 1 , ACT 2 , ACT 3 , ACT 4 , ACT 5 , ACT 6 , and ACTd) of the transistors (T 1 , T 2 , T 3 , T 4 , T 5 , T 6 , and Td) are in a same layer. In another example, the active layers (ACT 1 , ACT 2 , ACT 3 , ACT 4 , ACT 5 , ACT 6 , and ACTd), the source electrodes (S 1 , S 2 , S 3 , S 4 , S 5 , S 6 , Ss, and Sd), and the drain electrodes (D 1 , D 2 , D 3 , D 4 , D 5 , D 6 , and Dd) of the transistors (T 1 , T 2 , T 3 , T 4 , T 5 , T 6 , and Td) are in a same layer. 
     Referring to  FIG.  4 B , in some embodiments, the unitary structure of the semiconductor material layer further includes the plurality of first reset signal lines Vint 1 . The plurality of first reset signal lines Vint 1  are in a same layer as at least the active layers (e.g., ACT 1 , ACT 2 , ACT 3 , ACT 4 , ACT 5 , ACT 6 , and ACTd) of one or more the transistors (e.g., T 1 , T 2 , T 3 , T 4 , T 5 , T 6 , and Td). 
     As used herein, the active layer refers to a component of the transistor comprising at least a portion of the semiconductor material layer whose orthographic projection on the base substrate overlaps with an orthographic projection of a gate electrode on the base substrate. As used herein, a source electrode refers to a component of the transistor connected to one side of the active layer, and a drain electrode refers to a component of the transistor connected to another side of the active layer. In the context of a double-gate type transistor (for example, the third transistor T 3 ), the active layer refers to a component of the transistor comprising a first portion of the semiconductor material layer whose orthographic projection on the base substrate overlaps with an orthographic projection of a first gate on the base substrate, a second portion of the semiconductor material layer whose orthographic projection on the base substrate overlaps with an orthographic projection of a second gate on the base substrate, and a third portion between the first portion and the second portion. In the context of a double-gate type transistor, a source electrode refers to a component of the transistor connected to a side of the first portion distal to the third portion, and a drain electrode refers to a component of the transistor connected to a side of the second portion distal to the third portion. 
     Referring to  FIG.  3   ,  FIG.  4 A , and  FIG.  4 C , the first conductive layer in some embodiments includes a gate electrode G 1  of the first transistor T 1 , a gate electrode G 3  of the third transistor T 3 , a gate electrode G 6  of the sixth transistor T 6 , a plurality of light emitting control signal lines em, and a first capacitor electrode Ce 1  of the storage capacitor Cst. Various appropriate electrode materials and various appropriate fabricating methods may be used to make the first conductive layer. For example, a conductive material may be deposited on the substrate by a plasma-enhanced chemical vapor deposition (PECVD) process and patterned. Examples of appropriate conductive materials for making the first conductive layer include, but are not limited to, aluminum, copper, molybdenum, chromium, aluminum copper alloy, copper molybdenum alloy, molybdenum aluminum alloy, aluminum chromium alloy, copper chromium alloy, molybdenum chromium alloy, copper molybdenum aluminum alloy, and the like. Optionally, the gate electrode G 1  of the first transistor T 1 , the gate electrode G 3  of the third transistor T 3 , the gate electrode G 6  of the sixth transistor T 6 , the plurality of light emitting control signal lines em, and the first capacitor electrode Ce 1  are in a same layer. 
     As used herein, the term “same layer” refers to the relationship between the layers simultaneously formed in the same step. In one example, the plurality of light emitting control signal lines em and the first capacitor electrode Ce 1  are in a same layer when they are formed as a result of one or more steps of a same patterning process performed in a same layer of material. In another example, the plurality of light emitting control signal lines em and the first capacitor electrode Ce 1  can be formed in a same layer by simultaneously performing the step of forming the plurality of light emitting control signal lines em, and the step of forming the first capacitor electrode Ce 1 . The term “same layer” does not always mean that the thickness of the layer or the height of the layer in a cross-sectional view is the same. 
     In some embodiments, a respective gate line of the plurality of gate lines comprises a plurality of metal blocks (e.g., G 3  in  FIG.  4 C ) spaced apart from each other in a first conductive layer, and a metal line (e.g., GL in  FIG.  4 E ) along a first direction in the first signal line layer. The signal line along the first direction is connected to the plurality of metal blocks, respectively. The metal line in the first signal line layer can be made with a metallic material having a relatively low resistance, as compared to the metallic material in the first conductive layer. By having this design, the overall resistance of the gate line can be lowered. 
     In some embodiments, referring to  FIG.  4 A  to  FIG.  4 C , and  FIG.  5 A , a respective metal block of the plurality of metal blocks G 3  has a L shape. An orthographic projection of a first channel part of the active layer ACT 3  of the third transistor T 3  on the base substrate BS overlaps with an orthographic projection of a first metal portion of the respective metal block of the plurality of metal blocks G 3  on the base substrate BS. An orthographic projection of a second channel part of the active layer ACT 3  of the third transistor T 3  on the base substrate BS overlaps with an orthographic projection of a second metal portion of the respective metal block of the plurality of metal blocks G 3  on the base substrate BS. The first metal portion and the second metal portion are a first gate electrode and a second gate electrode of the third transistor T 3 . 
     Referring to  FIG.  3   ,  FIG.  4 A , and  FIG.  4 D , the second conductive layer in some embodiments includes a second capacitor electrode Ce 2  of the storage capacitor Cst. Various appropriate conductive materials and various appropriate fabricating methods may be used to make the second conductive layer. For example, a conductive material may be deposited on the substrate by a plasma-enhanced chemical vapor deposition (PECVD) process and patterned. Examples of appropriate conductive materials for making the second conductive layer include, but are not limited to, aluminum, copper, molybdenum, chromium, aluminum copper alloy, copper molybdenum alloy, molybdenum aluminum alloy, aluminum chromium alloy, copper chromium alloy, molybdenum chromium alloy, copper molybdenum aluminum alloy, and the like. 
     Referring to  FIG.  3   ,  FIG.  4 A , and  FIG.  4 E , the first signal line layer in some embodiments includes a plurality of first low voltage signal lines Vss 1 , a plurality of first reset control signal lines rst 1 , a plurality of gate lines GL, a plurality of first high voltage signal lines Vdd 1 , a plurality of second reset control signal lines rst 2 , and a node connecting line Cln. Referring to  FIG.  5 A , the node connecting line Cln connects the first capacitor electrode Ce 1  and the source electrode S 3  of the third transistor T 3  in a respective pixel driving circuit together. Various appropriate conductive materials and various appropriate fabricating methods may be used to make the first signal line layer. For example, a conductive material may be deposited on the substrate by a plasma-enhanced chemical vapor deposition (PECVD) process and patterned. Examples of appropriate conductive materials for making the first signal line layer include, but are not limited to, aluminum, copper, molybdenum, chromium, aluminum copper alloy, copper molybdenum alloy, molybdenum aluminum alloy, aluminum chromium alloy, copper chromium alloy, molybdenum chromium alloy, copper molybdenum aluminum alloy, and the like. Optionally, the plurality of first low voltage signal lines Vss 1 , the plurality of first reset control signal lines rst 1 , the plurality of gate lines GL, the plurality of first high voltage signal lines Vdd 1 , the plurality of second reset control signal lines rst 2 , and the node connecting line Cln are in a same layer. 
     In some embodiments, the respective first reset control signal line rst 1  include a plurality of first metal blocks spaced apart from each other in a first conductive layer, and a first metal line along a first direction in the first signal line layer, the first metal line along the first direction being connected to the plurality of first metal blocks, respectively. In some embodiments, the respective second reset control signal line comprises a plurality of second metal blocks spaced apart from each other in the first conductive layer, and a second metal line along the first direction in the first signal line layer, the second metal line along the first direction being connected to the plurality of second metal blocks, respectively. 
     In some embodiments, a respective first low voltage signal line of a plurality of first low voltage signal lines Vss 1  includes a first linear portion, a second linear portion, and a connecting portion connecting the first linear portion and the second linear portion. A virtual extension of the first linear portion crosses over the plurality of first metal blocks (e.g., G 1  in  FIG.  4 C ) of the respective first reset control signal line rst 1 . A virtual extension of the second linear portion is spaced apart from the plurality of first metal blocks, e.g., does not cross over the plurality of first metal blocks (e.g., G 1  in  FIG.  4 C ) of the respective first reset control signal line rst 1 . An orthographic projection of the second linear portion on a base substrate is spaced apart from orthographic projections of the plurality of first metal blocks.  FIG.  4 J  is a diagram illustrating a relative position between a respective one of a plurality of first low voltage signal lines and a plurality of first metal blocks of a respective first reset control signal line in some embodiments according to the present disclosure. Referring to  FIG.  4 J , a respective first low voltage signal line of a plurality of first low voltage signal lines Vss 1  includes a first linear portion LP 1 , a second linear portion LP 2 , and a connecting portion CP connecting the first linear portion LP 1  and the second linear portion LP 2 . A virtual extension VE of the first linear portion LP 1  crosses over the plurality of first metal blocks (G 1 ) of the respective first reset control signal line rst 1 . A virtual extension of the second linear portion LP 2  is spaced apart from the plurality of first metal blocks, e.g., does not cross over the plurality of first metal blocks (G 1 ) of the respective first reset control signal line rst 1 . 
     Referring to  FIG.  3   ,  FIG.  4 A , and  FIG.  4 F , the second signal line layer in some embodiments includes a plurality of data line DL, a plurality of second low voltage signal lines Vss 2 , a plurality of second reset signal lines Vint 2 , and a plurality of second high voltage signal lines Vdd 2 . Various appropriate conductive materials and various appropriate fabricating methods may be used to make the second signal line layer. For example, a conductive material may be deposited on the substrate by a plasma-enhanced chemical vapor deposition (PECVD) process and patterned. Examples of appropriate conductive materials for making the second signal line layer include, but are not limited to, aluminum, copper, molybdenum, chromium, aluminum copper alloy, copper molybdenum alloy, molybdenum aluminum alloy, aluminum chromium alloy, copper chromium alloy, molybdenum chromium alloy, copper molybdenum aluminum alloy, and the like. Optionally, the plurality of data line DL, the plurality of second low voltage signal lines Vss 2 , the plurality of second reset signal lines Vint 2 , and the plurality of second high voltage signal lines Vdd 2  are in a same layer. 
     Referring to  FIG.  4 F , in some embodiments, a minimal distance between a respective second reset signal line of the plurality of second reset signal lines Vint 2  and a respective second low voltage signal line of the plurality of second low voltage signal lines Vss 2  that is most adjacent to the respective second reset signal line is less than a minimal distance between the respective second reset signal line and a respective data line of a plurality of data line DL that is most adjacent to the respective second reset signal line. In some embodiments, a total of three data lines and a total of one second low voltage signal line are between two most adjacent second reset signal lines of the plurality of second reset signal lines Vint 2 . Optionally, a total of three data lines, a total of one second low voltage signal line, and a total of three second high voltage signal lines are between two most adjacent second reset signal lines of the plurality of second reset signal lines Vint 2 . 
     Referring to  FIG.  3   ,  FIG.  4 D ,  FIG.  4 E , and  FIG.  5 A , in some embodiments, an orthographic projection of the second capacitor electrode Ce 2  on a base substrate BS completely covers, with a margin, an orthographic projection of the first capacitor electrode Ce 1  on the base substrate BS except for a hole region H in which a portion of the second capacitor electrode Ce 2  is absent. In some embodiments, the first signal line layer includes a node connecting line Cln on a side of the inter-layer dielectric layer ILD away from the second capacitor electrode Ce 2 . The node connecting line Cln is in a same layer as the plurality of first low voltage signal lines Vss 1 , the plurality of first reset control signal lines rst 1 , the plurality of gate lines GL, the plurality of first high voltage signal lines Vdd 1 , and the plurality of second reset control signal lines rst 2 . Optionally, the display panel further includes a first connecting via cv 1  in the hole region H and extending through the inter-layer dielectric layer ILD and the insulating layer IN. Optionally, the node connecting line Cln is connected to the first capacitor electrode Ce 1  through the first connecting via cv 1 . In some embodiments, the first capacitor electrode Ce 1  is on a side of the gate insulating layer IN away from the base substrate BS. Optionally, the display panel further includes a first connecting via cv 1  and a second connecting via cv 2 . The first connecting via cv 1  is in the hole region H and extends through the inter-layer dielectric layer ILD and the insulating layer IN. The second connecting via cv 2  extends through the inter-layer dielectric layer ILD, the insulating layer IN, and the gate insulating layer GI. Optionally, the node connecting line Cln is connected to the first capacitor electrode Ce 1  through the first connecting via cv 1 , and is connected node connecting line Cln is connected the semiconductor material layer SML through the second connecting via cv 2 . Optionally, the node connecting line Cln is connected to the source electrode S 3  of third transistor T 3 , as depicted in  FIG.  5 A . 
     In some embodiments, referring to  FIG.  4 D , the second capacitor electrode Ce 2  includes an extension E extending away from an electrode main body emb of the second capacitor electrode Ce 2 . Referring to  FIG.  4 A , an orthographic projection of the extension E on a base substrate at least partially overlaps with an orthographic projection of an active layer of a third transistor T 3  of the respective pixel driving circuit. A portion of the extension E is between a first node N 1  of the respective pixel driving circuit and a respective data line of the plurality of data lines dl, configured to prevent interference from signals passing through the respective data line to the first node N 1 . A portion of the extension E is between the node connecting line Cln and a respective data line of the plurality of data lines dl. 
     By having the extension E, the active layer of the third transistor can be protected from irradiation. Because the extension E is part of the second capacitor electrode, the extension E has a stable voltage level, obviating the need to electrically connecting the extension E to a signal line having a stable voltage level. 
     Referring to  FIG.  4 A  to  FIG.  4 F , the third transistor T 3  includes a first gate electrode and a second gate electrode. An orthographic projection of the first gate electrode on the base substrate overlaps with an orthographic projection of a first channel part of the ACT 3  of the third transistor T 3  on the base substrate. An orthographic projection of the second gate electrode on the base substrate overlaps with an orthographic projection of a second channel part of the active layer ACT 3  of the third transistor T 3  on the base substrate. The active layer ACT 3  of the third transistor T 3  further includes a portion connecting the first channel part and the second channel part. The orthographic projection of the extension E on a base substrate at least partially overlaps with an orthographic projection of the portion connecting the first channel part and the second channel part on the base substrate. 
     In some embodiments, the extension E includes a first extension part along a first direction DR 1  and a second extension part along a second direction DR 2 . The first extension part connects the second extension part with the electrode main body emb of the second capacitor electrode Ce 2 . In some embodiments, an orthographic projection of the second extension part on the base substrate at least partially overlaps with the orthographic projection of the active layer ACT 3  of the third transistor T 3  of the respective pixel driving circuit on the base substrate. 
     In some embodiments, the second extension part includes a shielding portion and a non-shielding portion. An orthographic projection of the shielding portion on the base substrate at least partially overlaps with the orthographic projection of the active layer ACT 3  of the third transistor T 3  of the respective pixel driving circuit on the base substrate. An orthographic projection of the non-shielding portion on the base substrate is non-overlapping with the orthographic projection of the active layer ACT 3  of the third transistor T 3  of the respective pixel driving circuit on the base substrate. A line width of the shielding portion is greater than a line width of the non-shielding portion, ensuring that the active layer ACT 3  of the third transistor T 3  of the respective pixel driving circuit is shielded. 
     In some embodiments, an orthographic projection of the first extension part on the base substrate at least partially overlaps with an orthographic projection of the node connecting line Cln on the base substrate. The first extension part is between the node connecting line Cln and a respective data line of the plurality of data lines dl. The first extension part between the node connecting line Cln and the respective data line is configured to prevent interference to the first node N 1  from signals passing through the respective data line. 
     In some embodiments, an orthographic projection of the first extension part on a line extending along the second direction at least partially overlaps with an orthographic projection of the node connecting line on the line. The first extension part is configured to prevent interference to the first node N 1  from signals transmitting along the first direction. 
     In some embodiments, an orthographic projection of the respective one of the plurality of second high voltage signal lines Vdd 2  on the base substrate covers an orthographic projection of the node connecting line Cln on the base substrate. By having the respective one of the plurality of second high voltage signal lines Vdd 2  shielding the node connecting line Cln, a voltage level at the node N 1  can be stabilized because a constant voltage level is provided to the respective one of the plurality of second high voltage signal lines Vdd 2 . 
     In some embodiments, an orthographic projection of the respective one of the plurality of second high voltage signal lines Vdd 2  on the base substrate at least partially overlaps with an orthographic projection of at least one gate electrode of the third transistor T 3  on the base substrate. By having the respective one of the plurality of second high voltage signal lines Vdd 2  shielding the at least one gate electrode of the third transistor T 3 , a voltage level at the node N 1  can be further stabilized. 
       FIG.  6 A  is a diagram illustrating the structure of an interconnected low voltage supply network, an interconnected reset signal supply network, and an interconnected high voltage supply network in a display panel in some embodiments according to the present disclosure. The interconnected low voltage supply network includes signal lines in a display area of the display panel. The interconnected low voltage supply network is configured to provide a low voltage signal to cathodes of the plurality of light emitting elements. The interconnected reset signal supply network is configured to provide a reset signal to a plurality of pixel driving circuits. The interconnected reset signal supply network includes signal lines in a display area of the display panel. The interconnected high voltage supply network is configured to provide a high voltage signal to a plurality of pixel driving circuits. The interconnected high voltage supply network includes signal lines in a display area of the display panel. In one example, a first voltage signal line is a low voltage signal line, and a second voltage signal line is a high voltage signal line. 
       FIG.  6 B  is a diagram illustrating the structure of an interconnected low voltage supply network in a display panel in some embodiments according to the present disclosure. Referring to  FIG.  6 A  and  FIG.  6 B , the interconnected low voltage supply network in some embodiments includes a plurality of first low voltage signal lines Vss 1  respectively along a first direction DR 1 ; and a plurality of second low voltage signal lines Vss 2  respectively along a second direction DR 2 . The plurality of first low voltage signal lines Vss 1  respectively cross over the plurality of second low voltage signal lines Vss 2 . A respective one of the plurality of first low voltage signal lines Vss 1  is connected to at least multiple ones of the plurality of second low voltage signal lines Vss 2 . A respective one of the plurality of second low voltage signal lines Vss 2  is connected to at least multiple ones of the plurality of first low voltage signal lines Vss 1 . 
       FIG.  5 B  is a cross-sectional view along a B-B′ line in  FIG.  4 A . Referring to  FIG.  5 B ,  FIG.  6 A , and  FIG.  6 B , in some embodiments, the first signal line layer SL 1  includes the plurality of first low voltage signal lines Vss 1 , and the second signal line layer SL 2  includes the plurality of second low voltage signal lines Vss 2 . The plurality of first low voltage signal lines Vss 1  and the plurality of second low voltage signal lines Vss 2  interconnect through first vias v 1   s  respectively extending through the planarization layer PLN. At least some of the first vias are in the display area. A respective one of the plurality of first low voltage signal lines Vss 1  is connected to at least multiple ones of the plurality of second low voltage signal lines Vss 2  respectively through multiple first vias extending through the planarization layer PLN. A respective one of the plurality of second low voltage signal lines Vss 2  is connected to at least multiple ones of the plurality of first low voltage signal lines Vss 1  respectively through multiple first vias extending through the planarization layer PLN. 
       FIG.  6 C  is a diagram illustrating the structure of an interconnected reset signal supply network in a display panel in some embodiments according to the present disclosure. Referring to  FIG.  6 A  and  FIG.  6 C , the interconnected reset signal supply network in some embodiments includes a plurality of first reset signal lines Vint 1  respectively along a first direction DR 1 ; and a plurality of second reset signal lines Vint 2  respectively along a second direction DR 2 . The plurality of first reset signal lines Vint 1  respectively cross over the plurality of second reset signal lines Vint 2 . A respective one of the plurality of first reset signal lines Vint 1  is connected to at least multiple ones of the plurality of second reset signal lines Vint 2 . A respective one of the plurality of second reset signal lines Vint 2  is connected to at least multiple ones of the plurality of first reset signal lines Vint 1 . 
       FIG.  5 C  is a cross-sectional view along a C-C′ line in  FIG.  4 A . Referring to  FIG.  5 C ,  FIG.  6 A , and  FIG.  6 C , in some embodiments, the semiconductor material layer SML includes the plurality of first reset signal lines Vint 1 , and the second signal line layer SL 2  includes the plurality of second reset signal lines Vint 2 . The plurality of first reset signal lines Vint 1  and the plurality of second reset signal lines Vint 2  interconnect through second vias v 2   s  respectively extending through at least the planarization layer PLN. In one example, the plurality of first reset signal lines Vint 1  and the plurality of second reset signal lines Vint 2  interconnect through second vias v 2   s , a respective second via extending through the planarization layer PLN, the inter-layer dielectric layer ILD, the insulating layer IN, and the gate insulating layer GI. A respective one of the plurality of first reset signal lines Vint 1  is connected to at least multiple ones of the plurality of second reset signal lines Vint 2  respectively through multiple second vias extending through at least the planarization layer PLN. A respective one of the plurality of second reset signal lines Vint 2  is connected to at least multiple ones of the plurality of first reset signal lines Vint 1  respectively through multiple second vias extending through at least the planarization layer PLN. 
     Optionally, the plurality of first reset signal lines Vint 1  include a semiconductor material; and the plurality of second reset signal lines Vint 2  include a metallic material. Optionally, the plurality of first reset signal lines Vint 1  and at least active layers (e.g., ACTd, and ACT 1  to ACT 6 ) of a plurality of thin film transistors (e.g., Td, and T 1  to T 6 ) are in the semiconductor material layer SML, and include a same semiconductor material. 
     Alternatively, the reset signal lines (one or both of the plurality of first reset signal lines Vint 1  and the plurality of second reset signal lines Vint 2 ) may be disposed in the first conductive layer. Alternatively, the reset signal lines (one or both of the plurality of first reset signal lines Vint 1  and the plurality of second reset signal lines Vint 2 ) may be disposed in the first signal line layer. Alternatively, the reset signal lines (one or both of the plurality of first reset signal lines Vint 1  and the plurality of second reset signal lines Vint 2 ) may be disposed in the second conductive layer. Alternatively, the reset signal lines (one or both of the plurality of first reset signal lines Vint 1  and the plurality of second reset signal lines Vint 2 ) may be disposed in the second signal line layer. Alternatively, the plurality of first reset signal lines Vint 1  and the plurality of second reset signal lines Vint 2  are in a same layer, interconnecting with each other to form a network. 
       FIG.  6 D  is a diagram illustrating the structure of an interconnected high voltage supply network in a display panel in some embodiments according to the present disclosure. Referring to  FIG.  6 A  and  FIG.  6 D , the interconnected high voltage supply network in some embodiments includes a plurality of first high voltage signal lines Vdd 1  respectively along a first direction DR 1 ; and a plurality of second high voltage signal lines Vdd 2  respectively along a second direction DR 2 . The plurality of first high voltage signal lines Vdd 1  respectively cross over the plurality of second high voltage signal lines Vdd 2 . A respective one of the plurality of first high voltage signal lines Vdd 1  is connected to at least multiple ones of the plurality of second high voltage signal lines Vdd 2 . A respective one of the plurality of second high voltage signal lines Vdd 2  is connected to at least multiple ones of the plurality of first high voltage signal lines Vdd 1 . 
       FIG.  5 D  is a cross-sectional view along a D-D′ line in  FIG.  4 A . Referring to  FIG.  5 D ,  FIG.  6 A , and  FIG.  6 D , in some embodiments, the first signal line layer SL 1  includes the plurality of first high voltage signal lines Vdd 1 , and the second signal line layer SL 2  includes the plurality of second high voltage signal lines Vdd 2 . A respective one of the plurality of first high voltage signal lines Vdd 1  is connected to second capacitor electrode through one or more third vias v 3   s  respectively extending through the inter-layer dielectric layer ILD. A respective one of the plurality of first high voltage signal lines Vdd 1  is connected to at least multiple ones of the plurality of second high voltage signal lines Vdd 2  respectively through multiple third vias extending through the planarization layer PLN. A respective one of the plurality of second high voltage signal lines Vdd 2  is connected to at least multiple ones of the plurality of first high voltage signal lines Vdd 1  respectively through multiple third vias extending through the planarization layer PLN. By having the second capacitor electrode connected to the respective one of the plurality of first high voltage signal lines Vdd 1 , resistance of the respective one of the plurality of first high voltage signal lines Vdd 1  can be reduced. 
       FIG.  5 E  is a cross-sectional view along a E-E′ line in  FIG.  4 A . Referring to  FIG.  5 E ,  FIG.  6 A , and  FIG.  6 D , in some embodiments, the first signal line layer SL 1  includes the plurality of first high voltage signal lines Vdd 1 , and the second signal line layer SL 2  includes the plurality of second high voltage signal lines Vdd 2 . A respective one of the plurality of first high voltage signal lines Vdd 1  is connected to second capacitor electrode through one or more third vias v 3   s  respectively extending through the inter-layer dielectric layer ILD. A respective one of the plurality of second high voltage signal line Vdd 2  is connected to a respective one of the plurality of first high voltage signal lines Vdd 1  through one or more fourth vias v 4   s  respectively extending through the planarization layer PLN. A respective one of the plurality of first high voltage signal lines Vdd 1  is connected to the source electrode S 4  of the fourth transistor through a third connecting via cv 4  extending through the inter-layer dielectric layer ILD, the insulating layer IN, and the gate insulating layer GI. 
       FIG.  4 G  is a diagram illustrating the structure of a respective one of a plurality of first high voltage signal lines in some embodiments according to the present disclosure. Referring to  FIG.  4 G , the respective one of a plurality of first high voltage signal lines Vdd 1  in some embodiments includes a main body md extending along the first direction DR 1 , a first protrusion pd 1  protruding away from the main body md along the second direction DR 2 , and a second protrusion pd 2  protruding away from the first protrusion pd 1  along the second direction DR 2 . The second protrusion pd 2  connects to the main body md through the first protrusion pd 1 . The first protrusion pd 1  is a portion of the respective one of a plurality of first high voltage signal lines Vdd 1  where the respective one of a plurality of first high voltage signal lines Vdd 1  connects to the second capacitor electrode. The second protrusion pd 2  is a portion of the respective one of a plurality of first high voltage signal lines Vdd 1  where the respective one of a plurality of first high voltage signal lines Vdd 1  connects to the source electrode of the fourth transistor. The second protrusion pd 2  is a portion of the respective one of the plurality of second high voltage signal line Vdd 2  where the respective one of the plurality of second high voltage signal line Vdd 2  is connected to a respective one of the plurality of first high voltage signal lines Vdd 1  through one or more vias. A drain electrode of the fourth transistor is connected to a source electrode of a driving transistor. 
       FIG.  4 H  is a diagram illustrating the layout of anodes of light emitting elements with respect to pixel driving circuits of a display panel in some embodiments according to the present disclosure.  FIG.  4 I  is a diagram illustrating the structure of anodes, a first signal line layer, and a second signal line layer in a display panel in some embodiments according to the present disclosure. Referring to  FIG.  4 H  and  FIG.  4 I , the display panel in some embodiments further includes a plurality of anodes respectively of the plurality of light emitting elements, for example, a first anode AD 1 , a second anode AD 2 , and a third anode AD 3  as depicted in  FIG.  4 H . A respective anode is connected to an anode contact pad through a via extending through a second planarization layer (e.g., PLN 2  in  FIG.  5 A  to  FIG.  5 E ), and the anode contact pad is connected to a relay electrode through a via extending through the planarization layer (e.g., PLN in  FIG.  5 A  to  FIG.  5 E ). The relay electrode is connected to the N 4  node (e.g., the drain electrode of the fifth transistor) through a via extending through the inter-layer dielectric layer. 
     Referring to  FIG.  4 H ,  FIG.  4 I ,  FIG.  4 E , and  FIG.  4 F , in one example, the first anode AD 1  is connected to a first anode contact pad ACP 1  through a via extending through the second planarization layer, the first anode contact pad ACP 1  is connected to a first relay electrode RE 1  through a via extending through the planarization layer; the second anode AD 2  is connected to a second anode contact pad ACP 2  through a via extending through the second planarization layer, the second anode contact pad ACP 2  is connected to a second relay electrode RE 2  through a via extending through the planarization layer; the third anode AD 3  is connected to a third anode contact pad ACP 3  through a via extending through the second planarization layer, the third anode contact pad ACP 3  is connected to a third relay electrode RE 3  through a via extending through the planarization layer. 
     In some embodiments, referring to  FIG.  1   , the display panel further includes a gate-on-array circuit GOA in a peripheral area PA of the display panel. The interconnected low voltage supply network VSSN includes a first peripheral low voltage line pvss 1  in the peripheral area PA on a first side S 1  of the display panel.  FIG.  7 A  is a schematic diagram illustrating the structure in a first zoom-in region ZR 1  in  FIG.  1   .  FIG.  7 B  is a diagram illustrating the structure of a first signal line layer in a first region ZR 1  depicted in  FIG.  7 A .  FIG.  7 C  is a diagram illustrating the structure of a second signal line layer in a first region ZR 1  depicted in  FIG.  7 A .  FIG.  7 D  is a diagram illustrating the structure of a second planarization layer in a first region ZR 1  depicted in  FIG.  7 A .  FIG.  7 E  is a diagram illustrating the structure of an anode layer in a first region ZR 1  depicted in  FIG.  7 A .  FIG.  7 F  is a diagram illustrating the structure of a third planarization layer in a first region ZR 1  depicted in  FIG.  7 A .  FIG.  7 G  is a diagram illustrating the structure of a cathode layer in a first region ZR 1  depicted in  FIG.  7 A . Referring to  FIG.  7 A  to  FIG.  7 G , and  FIG.  1   , the display panel in the peripheral area PA on the first side S 1  of the display panel include a gate-on-array circuit GOA in the first signal line layer on a base substrate, a first peripheral low voltage line pvss 1  in the second signal line layer on a side of the gate-on-array circuit GOA away from the base substrate, a second planarization layer PLN 2  on a side of the first peripheral low voltage line pvss 1  away from the gate-on-array circuit GOA, an anode metal layer AML in an anode layer on a side of the second planarization layer PLN 2  away from the first peripheral low voltage line pvss 1 , a third planarization layer PLN 3  on a side of the anode metal layer AML away from the second planarization layer PLN 2 , and a cathode layer CDL on a side of the third planarization layer PLN 3  away from the anode metal layer AML. 
       FIG.  8    is a cross-sectional view along an F-F′ line in  FIG.  7 A . Referring to  FIG.  1   ,  FIG.  7   , and  FIG.  8   , in some embodiments, an orthographic projection of the first peripheral low voltage line pvss 1  on a base substrate BS at least partially overlaps with an orthographic projection of the gate-on-array circuit GOA on the base substrate BS. Optionally, the orthographic projection of the first peripheral low voltage line pvss 1  on a base substrate BS at least 80% (e.g., at least 85%, at least 90%, at least 95%, at least 99%) overlaps with the orthographic projection of the gate-on-array circuit GOA on the base substrate BS. 
     Referring to  FIG.  8   , the cathode layer CDL is connected to the anode metal layer AML through one or more first peripheral vias pv 1  in the peripheral area and extending through a third planarization layer PLN 3 , and the anode metal layer AML is connected to the first peripheral first voltage line pvss 1  through one or more second peripheral vias pv 2  in the peripheral area and extending through a second planarization layer PLN 2 , thereby providing the first voltage signal to the cathodes of the plurality of light emitting elements. The display panel includes a plurality of first gas releasing vias grv 1  extending through the first peripheral first voltage line pvss 1  for releasing gases in underneath insulating layer (e.g., the planarization layer PLN) during a fabrication process of the display panel. The display panel further includes a plurality of second gas releasing vias grv 2  extending through the anode metal layer AML for releasing gases in underneath insulating layer (e.g., the second planarization layer PLN 2 ) during a fabrication process of the display panel. 
     In some embodiments, the cathode layer CDL is a unitary cathode layer extending substantially throughout the display panel and functions as cathodes for the plurality of light emitting elements. Optionally, the one or more vias connecting the cathode layer CDL and the anode metal layer AML are limited in the peripheral area PA, and absent in the display area DA. The cathode layer CDL is connected to the interconnected low voltage supply network VSSN only through the anode metal layer AML. 
     In the present display panel, the low voltage line shares a same space as the gate-on-array circuit GOA. The display panel can be made with a very narrow bezel. In one example, the present display panel has a bezel width on the first side S 1  (or the side opposite to the first side S 1 ) of approximately 1.5 mm, as compared to 2.5 mm in a related display panel. 
     Moreover, in the present display panel, the connection between the low voltage line and the cathode layer CDL (through the anode metal layer) may be made exclusively in the peripheral area PA (e.g., in the GOA region), obviating the need of making vias (or any process at all) in the display area DA to connect the low voltage line and the cathode layer CDL. The display panel can be fabricated with much less complexity, significantly lowering occurrence of defects in the display panel. 
     The inventors of the present disclosure discover that, surprisingly and unexpectedly, the implementation of the interconnected low voltage supply network dramatically reduces a degree of voltage drop of the low voltage signal (e.g., the VSS signal) throughout the display panel.  FIG.  9 A  shows an IR drop in a display panel in some embodiments according to the present disclosure.  FIG.  9 B  shows an IR drop in a related display panel without an interconnected low voltage supply network. In  FIG.  9 A  and  FIG.  9 B , a degree of darkness indicates a degree of IR drop in a local region. Comparing  FIG.  9 A  and  FIG.  9 B , the degree of voltage drop in the embodiments according to the present disclosure is dramatically reduced as compared to the degree of voltage drop in the related display panel without an interconnected low voltage supply network. Overall, the IR drop is reduced from 1.5641 V to 1.2337 V (more than 20% reduction). The advantages of the present display panel are particularly meaningful for large size display panels. In the related display panel without an interconnected low voltage supply network, as shown in  FIG.  9 B , the VSS current concentrates at outmost two ports, leading to issues such as high current burns. For example, in the related display panel without an interconnected low voltage supply network, the VSS current at the outmost port is about 26.6% of the total VSS current. In the display panel in some embodiments according to the present disclosure, the VSS current at any port is less than 11% of the total VSS current, obviating the issue of large current burns. 
     To accommodate the implementation of the interconnected network in the present display panel, the layers and signal lines in the peripheral area have adopted a novel and unique structure that is advantageous in further reducing the bezel width, improving voltage uniformity throughout the display panel, and minimizing occurrence of defects in the display panel.  FIG.  10 A  is a schematic diagram illustrating the structure in a second zoom-in region ZR 2  in  FIG.  1   .  FIG.  10 B  is a schematic diagram illustrating the structure of low voltage signal lines in  FIG.  10 A .  FIG.  10 C  is a schematic diagram illustrating the structure of high voltage signal lines in  FIG.  10 A . Referring to  FIG.  1   ,  FIG.  10 A ,  FIG.  10 B , and  FIG.  10 C , in some embodiments, the display panel includes a peripheral high voltage signal line pvdd, a second peripheral low voltage signal line pvss 2 , and a third peripheral low voltage signal line pvss 3  in the peripheral area PA on a second side S 2  of the display panel. One or more of the plurality of second high voltage signal lines Vdd 2  are connected to the peripheral high voltage signal line pvdd. One or more of the plurality of second low voltage signal lines Vss 2  are connected to the second peripheral low voltage signal line pvss 2 . The second peripheral low voltage signal line pvss 2  and the third peripheral low voltage signal line pvss 3  are connected to each other through a plurality of bridges bg. Optionally, the plurality of first low voltage signal lines, the peripheral high voltage signal line pvdd, and the plurality of bridges are in a first signal line layer SL 1  (referring to, e.g.,  FIG.  5 A  for layer arrangement of the display panel). Optionally, the plurality of second high voltage signal lines Vdd 2 , the second peripheral low voltage signal line pvss 2  are in a second signal line layer SL 2 . Optionally, the third peripheral low voltage signal line pvss 3  includes a first sub-layer in the first signal line layer SL 1  and a second sub-layer in the second signal line layer SL 2 . 
       FIG.  10 D  is a schematic diagram illustrating the structure of reset signal lines in  FIG.  10 A . Referring to  FIG.  1   ,  FIG.  10 A , and  FIG.  10 D , in some embodiments, the display panel includes a peripheral reset signal line pvint in the peripheral area PA on a second side S 2  of the display panel. One or more of the plurality of second reset signal lines Vint 2  are connected to the peripheral reset signal line pvint. Optionally, the peripheral reset signal line pvint is in a layer different from the peripheral high voltage signal line pvdd and the peripheral low voltage signal line pvss 2 . Optionally, the peripheral reset signal line pvint is in a same layer as the plurality of second reset signal lines Vint 2 . Optionally, the peripheral reset signal line pvint is in a layer different from the plurality of second reset signal lines Vint 2 . In some embodiments, the peripheral reset signal line pvint includes a first part p 1  and a second part p 2 . Optionally, the first part p 1  includes a single layer conductive material in a same layer as the second signal line layer. Optionally, the second part has a double-layer structure including conductive materials respectively in the first signal line layer and the second signal line layer. 
     Referring to  FIG.  10 A , in some embodiments, the display panel further include a anode metal layer AML. In some embodiments, the anode metal layer AML is connected to the peripheral low voltage signal line pvss 2  through vias extending through one or more insulating layers. 
     Various appropriate implementations of the interconnected low voltage supply network may be practiced according to the present disclosure.  FIG.  11 A  is a diagram illustrating the structure of a first sub-network of an interconnected low voltage supply network in some embodiments according to the present disclosure.  FIG.  11 B  is a diagram illustrating the structure of a second sub-network of an interconnected low voltage supply network in some embodiments according to the present disclosure.  FIG.  11    C is a diagram illustrating the structure of an interconnected low voltage supply network comprising a first sub-network and a second sub-network in some embodiments according to the present disclosure. Referring to  FIG.  11 A  to  FIG.  11 C , the interconnected low voltage supply network in some embodiments includes a first sub-network formed by the plurality of first low voltage signal lines Vss 1  and a second sub-network formed by the plurality of second low voltage signal lines Vss 2 . Optionally, the first sub-network is in the first signal line layer and the second sub-network is in the second signal line layer. The plurality of first signal lines Vss 1  are electrically connected to the plurality of second signal lines Vss 2 . 
     In some embodiments, the plurality of first low voltage signal lines Vss 1  form a sub-network whereas the plurality of second low voltage signal lines Vss 2  do not form a sub-network. In some embodiments, the plurality of second low voltage signal lines Vss 2  form a sub-network whereas the plurality of first low voltage signal lines Vss 1  do not form a sub-network. 
       FIG.  12 A  is a diagram illustrating the structure of a plurality of first low voltage signal lines of an interconnected low voltage supply network in some embodiments according to the present disclosure.  FIG.  12 B  is a diagram illustrating the structure of a sub-network of a plurality of second low voltage signal lines of an interconnected low voltage supply network in some embodiments according to the present disclosure.  FIG.  12 C  is a diagram illustrating the structure of an interconnected low voltage supply network comprising a plurality of first low voltage signal lines and a sub-network of a plurality of second low voltage signal lines in some embodiments according to the present disclosure. Referring to  FIG.  12 A  to  FIG.  12 C , the plurality of first low voltage signal lines Vss 1  are separated from each other and does not form a sub-network, whereas the plurality of second low voltage signal lines Vss 2  form a sub-network. The plurality of first signal lines Vss 1  are electrically connected to the plurality of second signal lines Vss 2 . 
     In another aspect, the present invention provides a display apparatus, including the display panel described herein or fabricated by a method described herein, and one or more integrated circuits connected to the display panel. Examples of appropriate display apparatuses include, but are not limited to, an electronic paper, a mobile phone, a tablet computer, a television, a monitor, a notebook computer, a digital album, a GPS, etc. Optionally, the display apparatus is an organic light emitting diode display apparatus. Optionally, the display apparatus is a liquid crystal display apparatus. 
     In another aspect, the present disclosure provides a method of fabricating a display panel. In some embodiments, the method includes forming a plurality of light emitting elements; and forming an interconnected low voltage supply network configured to provide a low voltage signal to cathodes of the plurality of light emitting elements. Optionally, forming the interconnected low voltage supply network includes forming signal lines in a display area of the display panel. 
     The foregoing description of the embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form or to exemplary embodiments disclosed. Accordingly, the foregoing description should be regarded as illustrative rather than restrictive. Obviously, many modifications and variations will be apparent to practitioners skilled in this art. The embodiments are chosen and described in order to explain the principles of the invention and its best mode practical application, thereby to enable persons skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use or implementation contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents in which all terms are meant in their broadest reasonable sense unless otherwise indicated. Therefore, the term “the invention”, “the present invention” or the like does not necessarily limit the claim scope to a specific embodiment, and the reference to exemplary embodiments of the invention does not imply a limitation on the invention, and no such limitation is to be inferred. The invention is limited only by the spirit and scope of the appended claims. Moreover, these claims may refer to use “first”, “second”, etc. following with noun or element. Such terms should be understood as a nomenclature and should not be construed as giving the limitation on the number of the elements modified by such nomenclature unless specific number has been given. Any advantages and benefits described may not apply to all embodiments of the invention. It should be appreciated that variations may be made in the embodiments described by persons skilled in the art without departing from the scope of the present invention as defined by the following claims. Moreover, no element and component in the present disclosure is intended to be dedicated to the public regardless of whether the element or component is explicitly recited in the following claims.