OLED display panels

Abstract

The present invention provides an OLED display panel, wherein the edge film layer of the display area of ​​the OLED display panel includes a substrate, a bonding electrode located on the substrate, a pixel definition layer located on the bonding electrode, and a cathode layer located on the pixel definition layer, wherein the cathode layer is electrically connected to the bonding electrode; wherein the bonding electrode at the edge position of one side of the display area close to the frame area is located on the pixel definition layer, and a plurality of openings are provided on the surface of the pixel definition layer, and the intersection edge of the bonding electrode is provided with a plurality of protruding teeth corresponding to and engaging with the openings one by one; the present invention provides a mutually interlocking structure at the interface where the pixel definition layer and the bonding electrode are bonded, thereby increasing the adhesion between the pixel definition layer and the bonding electrode, further reducing the risk of the cathode layer and the bonding electrode layer of the OLED pixel being easily separated by bending force when bent and deformed, preventing the occurrence of peeling, thereby ensuring the normal display of the OLED display panel.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to an OLED display panel. Background Art

[0002] OLED display panels are widely used in the field of flat panel displays due to their advantages such as fast response speed, zero viewing angle display, and high contrast. Flexible OLED display panels are a hot topic.

[0003] Currently, display panels use an extremely narrow bezel design to meet people's requirements for the aesthetics of display panels. In the design of traditional OLED display panels, in order to ensure that the power routing layer has sufficient effective electrical contact area under the normal driving circuit, the width of the power routing layer on the left and right side frames is generally 400um to 600um. The power routing layer is extended to the edge of the display area and electrically connected to the cathode of the OLED pixel. The power routing layer is electrically connected to the corresponding driver IC, thereby realizing the transmission of the required electrical signal to the cathode.

[0004] When a flexible display panel with a narrow bezel is bent, after long-term bending and deformation, the cathode and power wiring layers of the OLED pixel are easily separated by the bending force, causing display defects, which requires improvement. Summary of the Invention

[0005] The present invention provides an OLED display panel that can solve the technical problem in the prior art that when a flexible display panel with a narrow frame is bent, after long-term bending and deformation, the cathode and power wiring layers of the OLED pixels are easily separated by the bending force, causing display defects.

[0006] The technical solutions provided by the present invention are as follows:

[0007] An embodiment of the present invention provides an OLED display panel, comprising a display area and a frame area surrounding the display area, wherein the OLED display panel comprises at least a substrate, a driving circuit layer located above the substrate, a pixel definition layer located above the driving circuit layer, and a cathode layer located above the pixel definition layer; wherein the OLED display panel further comprises a strapping electrode electrically connected to the cathode layer, wherein the strapping electrode extends from the frame area to the display area, and the strapping electrode is located on the pixel definition layer at an edge position on one side of the display area close to the frame area, and a plurality of openings are provided on the surface of the pixel definition layer, and the intersecting edges of the strapping electrodes are provided with a plurality of protrusions that correspond one-to-one and fit into the openings.

[0008] According to a preferred embodiment of the present invention, the opening is a groove, the depth of the groove is 1 mm to 2 mm, and the width of the groove is 0.1 mm to 0.5 mm.

[0009] According to a preferred embodiment of the present invention, the cross-sectional shape of the groove is rectangular, U-shaped, triangular or arc-shaped.

[0010] According to a preferred embodiment of the present invention, the OLED display panel is connected to a driver IC, and the bonding electrode is electrically connected to the driver IC.

[0011] According to a preferred embodiment of the present invention, the cathode layer at the edge of the frame area away from the display area is directly attached to the surface of the bonding electrode and is electrically connected to the bonding electrode.

[0012] According to a preferred embodiment of the present invention, in the display area, the pixel definition layers are arranged at intervals to form pixel openings, and light-emitting devices are arranged in the pixel openings.

[0013] According to a preferred embodiment of the present invention, the light-emitting devices all include an anode, a hole injection layer and a hole transport layer located above the anode, a light-emitting material layer located above the hole injection layer and the hole transport layer, an electron transport layer and an electron injection layer located above the light-emitting material layer, and the cathode layer located above the electron transport layer and the electron injection layer. The anodes and light-emitting material layers of any two adjacent light-emitting devices are separated from each other and share one cathode layer.

[0014] According to a preferred embodiment of the present invention, the driving circuit layer includes TFT devices arranged in an array, and the anode is electrically connected to the drain of the TFT device through a via hole.

[0015] According to a preferred embodiment of the present invention, an encapsulation layer is further provided on a side of the cathode layer away from the pixel definition layer, and the encapsulation layer is a stacked film layer of an inorganic layer and an organic layer.

[0016] According to a preferred embodiment of the present invention, the bonding electrode and the cathode layer are made of the same metal oxide, and the metal oxide is transparent ITO.

[0017] Beneficial effects of the present invention: An embodiment of the present invention provides an OLED display panel, preferably a flexible OLED display panel, comprising a display area and a frame area surrounding the display area. The OLED display panel comprises at least a substrate, a drive circuit layer located above the substrate, a pixel definition layer located above the drive circuit layer, and a cathode layer located above the pixel definition layer. The OLED display panel further comprises a bonding electrode electrically connected to the cathode layer, the bonding electrode extending from the frame area to the display area, the bonding electrode located at an edge of the display area near the frame area being located above the pixel definition layer, and a plurality of openings being provided on the surface of the pixel definition layer, and a plurality of protrusions corresponding to and engaging with the openings being provided at the junction of the bonding electrodes. The present invention provides a mutually interlocking structure at the interface where the pixel definition layer and the bonding electrode meet, thereby increasing the adhesion between the pixel definition layer and the bonding electrode, further reducing the risk of separation of the cathode layer and the bonding electrode layer of the OLED pixel under bending and deformation, and preventing peeling, thereby ensuring normal display of the OLED display panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figures 1 to 2 Schematic diagram of the film layer structure of an OLED display panel in the prior art.

[0020] Figure 3 A schematic diagram of a film layer structure at the edge of a display area of ​​an OLED display panel is provided in an embodiment of the present invention.

[0021] Figure 4 for Figure 3 A local enlarged schematic diagram of point A in the middle.

[0022] Figure 5 A schematic diagram of a partial film layer structure of an OLED display panel is provided in an embodiment of the present invention.

[0023] Figure 6 A schematic diagram of a film layer structure at the edge of another display area of ​​an OLED display panel is provided according to an embodiment of the present invention.

[0024] Figure 7 A schematic diagram of a film layer structure at the edge of another display area of ​​an OLED display panel is provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following descriptions of the various embodiments are made with reference to the accompanying drawings to illustrate specific embodiments in which the present invention may be implemented. Directional terms used in the present invention, such as [up], [down], [front], [back], [left], [right], [inside], [outside], and [side], are merely referenced to the directions in the accompanying drawings. Therefore, the directional terms used are intended to illustrate and facilitate understanding of the present invention, and are not intended to limit the present invention. In the drawings, units with similar structures are denoted by the same reference numerals. Dotted lines in the drawings indicate elements that do not exist in the structure and are merely used to illustrate the shape and position of the structure.

[0026] like Figure 1 As shown in FIG. 1 , the prior art provides a schematic diagram of an edge film layer of a display area of ​​an OLED display panel 10. The edge film layer of the display area of ​​the display panel 10 includes a bonding electrode 11, a pixel definition layer 12 located on the bonding electrode 11, and pixel units 13 arrayed on the pixel definition layer 12. The direct contact surface between the pixel definition layer 12 and the pixel units 13 is a flat portion. Figure 2 As shown, the prior art provides a schematic diagram of a portion of the film layers of a display panel 10. The display panel 10 includes a substrate, a light-emitting functional film layer located on the substrate, the light-emitting functional film layer including a bonding electrode 11, a pixel definition layer 12, a light-emitting device 13 located in an opening area of ​​the pixel definition layer 12, and a cathode 131 located on the pixel definition layer 12. The cathode 131 is attached to the edge of the pixel definition layer 12 and is electrically connected to the surface of the bonding electrode 11. When the flexible display panel 10 is bent, after long-term bending and deformation, the cathode 131 of the pixel unit 13 and the bonding electrode 11 layer are easily separated by the bending force, causing a technical problem of display defects.

[0027] To solve the above technical problems, an embodiment of the present invention provides an OLED display panel, preferably a flexible OLED display panel, comprising a display area and a frame area surrounding the display area, the OLED display panel comprising at least a substrate, a driving circuit layer located above the substrate, a pixel definition layer located above the driving circuit layer, and a cathode layer located above the pixel definition layer; the OLED display panel further comprises a bonding electrode electrically connected to the cathode layer, the bonding electrode extending from the frame area to the display area, the bonding electrode located at an edge of the display area near the frame area being located above the pixel definition layer, and a plurality of openings being provided on a surface of the pixel definition layer, the junction edge of the bonding electrode being provided with a plurality of protrusions corresponding to and engaging with the openings. The present invention provides a mutually interlocking structure at the interface where the pixel definition layer and the bonding electrode bond together, thereby increasing the adhesion between the pixel definition layer and the bonding electrode, further reducing the risk of separation of the cathode layer and the bonding electrode layer of the OLED pixel under bending and deformation, and preventing peeling, thereby ensuring normal display of the OLED display panel.

[0028] The cathode layer at the edge of the frame area away from the display area is directly attached to the surface of the overlapping electrode and is electrically connected to the overlapping electrode. In the display area, the pixel definition layers are spaced to form pixel openings, and light-emitting devices are arranged in the pixel openings. The light-emitting devices each include an anode, a hole injection layer and a hole transport layer located on the anode, a light-emitting material layer located on the hole injection layer and the hole transport layer, an electron transport layer and an electron injection layer located on the light-emitting material layer, and a cathode layer located above the electron transport layer and the electron injection layer. The anodes and light-emitting material layers of any two adjacent light-emitting devices are separated from each other and share a common cathode layer. The driving circuit layer includes an array of TFT devices, and the anodes are electrically connected to the drain electrodes of the TFT devices through vias. An encapsulation layer is also provided on the side of the cathode layer away from the pixel definition layer. The encapsulation layer is a superimposed film layer of an inorganic layer and an organic layer. The overlapping electrode and the cathode layer are made of a metal oxide of the same material, and the metal oxide is transparent ITO, so that the overlapping electrode and the cathode layer have good contact and are not easy to fall off.

[0029] Specifically, if Figure 3 and Figure 5 As shown, an embodiment of the present invention provides a schematic diagram of the film layer structure at the edge of the display area of ​​an OLED display panel 20; the edge film layer of the display area includes a substrate, a bonding electrode 21 located on the substrate, a pixel definition layer 22 located on the bonding electrode 21, and a cathode layer 24 located on the pixel definition layer 22. The cathode layer 24 is electrically connected to the driver IC (not shown) through the bonding electrode 21. The cathode layer 24 at the edge of the frame area away from the display area is directly attached to the surface of the bonding electrode 21 and is electrically connected to the bonding electrode 21.

[0030] The film layer of the display area includes a substrate, a driving circuit layer, a light-emitting functional layer, and an encapsulation layer stacked in sequence on the substrate: the substrate includes a first flexible layer, a first water-blocking layer, a second flexible layer, and a second water-blocking layer stacked in layers, the first flexible layer and the second flexible layer are preferably transparent polyimide, the first water-blocking layer and the second water-blocking layer are both hard coating layers, and the material of the hard coating layer is preferably silicon dioxide.

[0031] The driving circuit layer includes an array of TFT devices, each comprising a light-shielding layer disposed on a substrate, a buffer layer disposed on the substrate and covering the light-shielding layer, an active layer disposed on the buffer layer, a first gate insulating layer disposed on the active layer, a first gate disposed on the first gate insulating layer, a second gate insulating layer disposed on the first gate insulating layer and covering the first gate, a second gate disposed on the second gate insulating layer, a first interlayer insulating layer disposed on the second gate insulating layer and covering the second gate, a source and a drain disposed on the first interlayer insulating layer, a second interlayer insulating layer disposed on the first interlayer insulating layer and covering the source and drain, and a planarization layer disposed on the second interlayer insulating layer. The active layer includes a channel region corresponding to below the first gate insulating layer, and a source contact region and a drain contact region located on either side of the channel region. The source contact region and the drain contact region are made of a conductive metal oxide semiconductor material, while the channel region is made of a metal oxide semiconductor material that maintains semiconductor properties. A source contact hole and a drain contact hole are provided on the first interlayer insulating layer, the second gate insulating layer, and the first gate insulating layer, respectively corresponding to the source contact area and the drain contact area. The source and the drain are electrically connected to the source contact area and the drain contact area of ​​the active layer through the source contact hole and the drain contact hole, respectively. The orthographic projection of the light-shielding layer on the substrate covers the orthographic projection of the active layer on the substrate, so that the light-shielding layer can completely cover the active layer, preventing the active layer from being exposed to light, thereby avoiding negative drift of the threshold voltage of the TFT device.

[0032] The driving circuit layer includes TFT devices arranged in an array, and the light-emitting functional layer includes light-emitting devices 23 arranged in an array. Each light-emitting device 23 includes an anode, a hole injection layer and a hole transport layer located on the anode, a light-emitting material layer located on the hole injection layer and the hole transport layer, an electron transport layer and an electron injection layer located on the light-emitting material layer, and a cathode layer 24 located above the electron transport layer and the electron injection layer. The anode and the light-emitting material layer of any two adjacent light-emitting devices 23 are separated from each other, but share a cathode layer 24. The anode is electrically contacted with the drain in the TFT device through the anode via. The anode in this embodiment is formed by coating and then patterned. The specific preparation steps include coating, pre-curing, exposure, development, main curing, etching and stripping. The cathode layer 24 is formed by evaporation or magnetron sputtering.

[0033] The source electrode of the TFT device is preferably connected to the positive electrode of the driver IC. The negative electrode of the driver IC transmits the corresponding electrical signal to the cathode layer 24 via the bonding electrode 21. When the positive and negative electrodes of the driver IC are at a DC voltage of 2V to 10V, holes are generated at the anode and electrons are generated at the cathode. When these electrons and holes meet in the luminescent material layer, the electrons and holes are negatively charged and positively charged, respectively. They attract each other, stimulating the organic material in the luminescent material layer to emit light, thereby achieving normal operation of the OLED display panel 20. The brightness of the luminescent material layer can be adjusted by controlling the external power supply voltage: the higher the voltage, the higher the brightness, and vice versa.

[0034] In the display area of ​​this embodiment, the pixel definition layers are spaced to form pixel openings, and a light-emitting device 23 is arranged in the pixel opening. The light-emitting device includes three rows of sub-light-emitting devices, the first row of sub-light-emitting devices is red sub-light-emitting devices 231, the second row of sub-light-emitting devices is green sub-light-emitting devices 232, and the third row of sub-light-emitting devices is blue sub-light-emitting devices 233.

[0035] The encapsulation layer is located on and covers the light-emitting functional layer. It is a superimposed film layer of inorganic and organic layers. The encapsulation layer includes a first inorganic layer, an organic layer, and a second inorganic layer. The first and second inorganic layers are prepared by physical vapor deposition. The organic layer is generally printed using inkjet printing, which not only has high light transmittance but also effectively relieves stress in the inorganic layer. A flexible touch layer is also provided on the surface of the encapsulation layer, and a polarizing cover is also provided on the surface of the flexible touch layer.

[0036] In this embodiment, a mutually interlocking structure is provided on the interface where the pixel definition layer 22 and the overlapping electrode 21 are in contact at the edge position of one side of the display area close to the frame area, thereby increasing the adhesion between the pixel definition layer and the overlapping electrode, further reducing the risk of the cathode layer 24 and the overlapping electrode layer 21 of the OLED pixel being easily separated by the bending force when being bent and deformed, preventing the occurrence of peeling, and thus ensuring the normal display of the OLED display panel.

[0037] like Figure 4 As shown, at the interface where they are bonded, a plurality of openings 221 are provided on the surface of the pixel definition layer 22, and a plurality of protrusions 211 are provided on the intersecting edge of the bonding electrode 21, which correspond one-to-one with and engage with the openings 221. In other embodiments, a plurality of openings are provided on the surface of the bonding electrode 21, and a plurality of protrusions are provided on the intersecting edge of the pixel definition layer 22, which correspond one-to-one with and engage with the openings, but this is not limited here.

[0038] Figure 4 Combine Figure 3 The cross-sectional shape of the groove is preferably rectangular, U-shaped, triangular or arc-shaped. The pixel definition layer 22 above the bonding electrode 21 is designed to be concave-convex, and its opening 221 is a groove. The depth of the groove is 1mm to 2mm, and the width of the groove is 0.1mm to 0.5mm. The contact area between the cathode layer 24 and the pixel definition layer 22 in the above technical solution is increased, and the contact area with the bonding electrode 21 is increased, and the bonding is more stable, thereby reducing the risk of poor bonding between the cathode layer and the bonding electrode when the flexible OLED display panel is bent.

[0039] In other embodiments, the interface between the pixel definition layer 22 and the bonding electrode 21 includes multiple broken line surfaces or multiple arc surfaces. The interface is in a wave shape 25. Figure 6The interface between the pixel definition layer 22 and the bonding electrode 21 is a sawtooth shape 26, refer to Figure 7 , other structures follow Figure 3 Similar, no further description is given here.

[0040] As described above, the present invention provides a mutually interlocking structure at the interface where the pixel definition layer and the overlapping electrode are bonded, thereby increasing the adhesion between the pixel definition layer and the overlapping electrode, further reducing the risk of the cathode layer and the overlapping electrode layer of the OLED pixel being easily separated by the bending force when bent and deformed, preventing the occurrence of peeling, and thus ensuring the normal display of the OLED display panel.

[0041] In summary, although the present invention has been disclosed above with reference to preferred embodiments, the above preferred embodiments are not intended to limit the present invention. A person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. An OLED display panel comprising a display area and a frame area surrounding the display area, characterized in that: The OLED display panel at least includes a substrate, a driving circuit layer located on the substrate, a pixel definition layer located on the driving circuit layer, and a cathode layer located on the pixel definition layer; The OLED display panel further includes a strapping electrode electrically connected to the cathode layer, the strapping electrode extending from the frame area to the display area, the strapping electrode at an edge of the display area close to the frame area being located below the pixel definition layer, and a plurality of openings being provided on a surface of the pixel definition layer, a plurality of protrusions corresponding one-to-one with and engaging with the openings being provided on the junction edge of the strapping electrode, and the openings being grooves; The pixel definition layer and the bonding electrode are engaged with each other at the interface where they are attached.

2. The OLED display panel according to claim 1, wherein: The depth of the groove is 1 mm to 2 mm, and the width of the groove is 0.1 mm to 0.5 mm.

3. The OLED display panel according to claim 2, wherein: The cross-sectional shape of the groove is rectangular, U-shaped, triangular or arc-shaped.

4. The OLED display panel according to claim 1, wherein: The OLED display panel is connected to a driving IC, and the bonding electrode is electrically connected to the driving IC.

5. The OLED display panel according to claim 4, wherein: The cathode layer at the edge of the frame area away from the display area is directly attached to the surface of the bonding electrode and is electrically connected to the bonding electrode.

6. The OLED display panel according to claim 1, wherein: In the display area, the pixel definition layers are spaced apart to form pixel openings, and light-emitting devices are arranged in the pixel openings.

7. The OLED display panel according to claim 6, wherein: The light-emitting devices each include an anode, a hole injection layer and a hole transport layer located above the anode, a light-emitting material layer located above the hole injection layer and the hole transport layer, an electron transport layer and an electron injection layer located above the light-emitting material layer, and the cathode layer located above the electron transport layer and the electron injection layer. The anodes and light-emitting material layers of any two adjacent light-emitting devices are separated from each other and share a common cathode layer.

8. The OLED display panel according to claim 7, wherein: The driving circuit layer includes TFT devices arranged in an array, and the anode is electrically connected to the drain of the TFT device through a via hole.

9. The OLED display panel according to claim 1, wherein: An encapsulation layer is further provided on a side of the cathode layer away from the pixel definition layer. The encapsulation layer is a stacked film layer of an inorganic layer and an organic layer.

10. The OLED display panel according to claim 1, wherein: The bonding electrode and the cathode layer are made of metal oxide of the same material, and the metal oxide is transparent ITO.

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