CN110444562B

CN110444562B - Display panel and display device

Info

Publication number: CN110444562B
Application number: CN201910760750.1A
Authority: CN
Inventors: 樊腾; 崔霜; 郭恩卿; 李之升; 王程功; 王雪丹; 李庆; 杨婷慧; 翟峰
Original assignee: Chengdu Vistar Optoelectronics Co Ltd
Current assignee: Chengdu Vistar Optoelectronics Co Ltd
Priority date: 2019-08-16
Filing date: 2019-08-16
Publication date: 2021-12-21
Anticipated expiration: 2039-08-16
Also published as: CN110444562A

Abstract

The invention discloses a display panel and a display device, wherein the display panel comprises a plurality of light-emitting devices, and each light-emitting device comprises a planar film layer and a columnar structure protruding from the planar film layer; the driving back plate is provided with bonding pads in one-to-one correspondence with the light-emitting devices, the bonding pads are covered by the flexible conductive structures, and the columnar structures of the light-emitting devices are inserted into the flexible conductive structures so that the metal electrodes wrapping the columnar structures are electrically connected with the corresponding bonding pads. According to the technical scheme, the influence of wafer warpage on the binding yield is greatly reduced, and the problem of binding dislocation caused by thermal mismatch of the driving backboard and the substrate of the light-emitting device is effectively avoided.

Description

Display panel and display device

Technical Field

The embodiment of the invention relates to the technical field of display, in particular to a display panel and a display device.

Background

Micro LED (Micro Light Emitting Diode) is known as next generation Display technology by miniaturizing and matrixing the conventional LED, and the pixel size is below hundred micrometers, which inherits the advantages of low LED power consumption, high color saturation, fast reaction speed, large contrast, etc., the brightness is 30 times higher than that of OLED (Organic Light Emitting Diode), and the power consumption is only about 10% of that of LCD (Liquid Crystal Display), which is 50% of that of OLED.

In the traditional binding process, the electrodes on the two sides are bonded by adopting solder, but the epitaxial layer of the light-emitting device has the problem of wafer warpage, so that the welding yield of the electrodes on the two sides is influenced, and the driving back plate and the substrate of the light-emitting device have the problem of thermal mismatch during binding, so that the electrodes on the two sides are staggered, and the binding yield is further reduced.

Disclosure of Invention

The invention provides a display panel and a display device, which greatly reduce the influence of wafer warpage on binding yield and effectively avoid the problem of binding dislocation caused by thermal mismatch of a driving backboard and a light-emitting device substrate.

In a first aspect, an embodiment of the present invention provides a display panel, including:

a plurality of light emitting devices, each of the light emitting devices including a planar film layer and a columnar structure protruding from the planar film layer;

the driving back plate is provided with bonding pads in one-to-one correspondence with the light-emitting devices, the bonding pads are covered by the flexible conductive structures, and the columnar structures of the light-emitting devices are inserted into the flexible conductive structures so that the metal electrodes wrapping the columnar structures are electrically connected with the corresponding bonding pads.

Further, the epitaxial layer of the light-emitting device wraps the columnar structure, and the columnar structure is an N-type semiconductor structure; or, the planar film layer of the light-emitting device comprises an epitaxial layer of the light-emitting device and the columnar structure is an undoped semiconductor structure.

The light-emitting area of the light-emitting device is increased, the light-emitting brightness of the pixels is improved, the quantum confinement Taskk effect is weakened, the dislocation density of the light-emitting device is reduced, the light-emitting efficiency of the light-emitting device is improved, the influence of wafer warping on the binding yield is reduced, and the problem that heating causes thermal mismatch in the binding process and then binding dislocation is effectively avoided.

Furthermore, the epitaxial layer of the light-emitting device wraps the columnar structure, the columnar structure is an N-type semiconductor structure, the plane film layer of the light-emitting device comprises a mask layer, a plurality of through holes are formed in the mask layer, and the columnar structure is formed at the corresponding through holes.

The opening position of the mask layer is accurate, the position of the columnar structure can be accurately positioned, and the light emitting area of the light emitting device can be adjusted by adjusting the diameter of the opening of the mask layer.

Further, the planar film layer of the light emitting device includes an epitaxial layer of the light emitting device, the columnar structure is an undoped semiconductor structure, the epitaxial layer includes a plurality of patterned epitaxial structures, at least one columnar structure is arranged on one epitaxial structure, and the epitaxial structure and the columnar structure on the epitaxial structure form one light emitting device.

So that each light emitting device independently receives an anode signal to realize active driving of the light emitting device.

Furthermore, an insulating layer is arranged on the driving back plate, a plurality of limiting holes are formed in the insulating layer corresponding to the light emitting devices, and the corresponding bonding pads and the flexible conductive structures filled in the limiting holes are arranged in the limiting holes.

The method is favorable for playing a limiting role in binding the light-emitting device, and further improves the dislocation problem of the metal electrode and the bonding pad on the basis of realizing normal-temperature binding without heating to avoid the dislocation problem caused by thermal mismatch.

Furthermore, ultraviolet curing glue is filled in a gap between the light-emitting device and the driving back plate after the light-emitting device and the driving back plate are bonded.

The ultraviolet curing adhesive is used for fixedly bonding the light-emitting device and the driving back plate, and the problem that the light-emitting device and the corresponding bonding pad are staggered due to thermal mismatch caused by heating is avoided.

Further, the display panel further includes:

and the reflecting structures are arranged around the epitaxial layers of the corresponding light-emitting devices along the direction parallel to the display panel.

The reflection structure can reflect the light emitted to two sides by the light emitting device for displaying, so that the light emitting efficiency of the light emitting device is improved.

Furthermore, the columnar structure of the light-emitting device is positioned on one side of the planar film layer, which is close to the driving backboard, and the metal electrode of the light-emitting device is electrically connected with the corresponding bonding pad;

the display panel further comprises a cathode layer positioned on one side of the light-emitting device far away from the driving back plate, the planar film layer of the light-emitting device comprises a planar N-type semiconductor layer, the planar N-type semiconductor layer is a film layer far away from the columnar structure in the planar film layer, and the planar N-type semiconductor layer is electrically connected with the cathode layer;

preferably, the surface of the plane N-type semiconductor layer away from the columnar structure is provided with an etched pattern.

The light-emitting device receives corresponding anode signals and cathode signals to realize active driving, so that the total reflection degree of light rays on the surface of the plane N-type semiconductor layer far away from the columnar structure is reduced, and the light extraction rate of the light-emitting device is improved.

Further, the ratio of the height of the columnar structure along the direction perpendicular to the plane film layer to the maximum diameter of the cross section of the columnar structure parallel to the plane film layer direction is more than or equal to 2.

The height of the columnar structure in the direction perpendicular to the plane film layer is increased, the allowance of the contact part of the columnar structure and the soft conductive structure is increased, the influence of the warping of the wafer on the binding yield is reduced, and the binding yield of the light-emitting device and the driving back plate is further improved.

In a second aspect, an embodiment of the present invention further provides a display device, including the display panel according to the first aspect.

The embodiment of the invention provides a display panel and a display device, wherein the display panel comprises a plurality of light-emitting devices and a driving back plate, each light-emitting device comprises a planar film layer and a columnar structure protruding from the planar film layer, the driving back plate is provided with bonding pads in one-to-one correspondence with the light-emitting devices, the bonding pads are covered by a flexible conductive structure, and the columnar structure of the light-emitting device is inserted into the flexible conductive structure so that a metal electrode comprising the columnar structure is electrically connected with the corresponding bonding pads, so that the influence of wafer warping on the binding yield is greatly reduced, and the problem of binding dislocation caused by thermal mismatch of the driving back plate and a substrate of the light-emitting device is effectively avoided.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings in which:

fig. 1 is a schematic cross-sectional structure diagram of a display panel according to an embodiment of the present invention;

fig. 2 is a schematic cross-sectional view of a light emitting device according to an embodiment of the present invention;

FIG. 3 is a schematic cross-sectional view of a prior art display panel;

fig. 4 is a schematic cross-sectional view of another light-emitting device according to an embodiment of the present invention;

fig. 5 is a schematic cross-sectional view illustrating another display panel according to an embodiment of the invention;

fig. 6 is a schematic cross-sectional view of another light-emitting device according to an embodiment of the present invention;

fig. 7 is a schematic cross-sectional view illustrating another display panel according to an embodiment of the invention;

fig. 8 is a schematic cross-sectional view illustrating another display panel according to an embodiment of the invention;

fig. 9 is a schematic cross-sectional view illustrating another display panel according to an embodiment of the invention;

fig. 10 is a schematic structural diagram of a display device according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures. Throughout this specification, the same or similar reference numbers refer to the same or similar structures, elements, or processes. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

Fig. 1 is a schematic cross-sectional structure diagram of a display panel according to an embodiment of the present invention, and fig. 2 is a schematic cross-sectional structure diagram of a light emitting device according to an embodiment of the present invention. With reference to fig. 1 and 2, the display panel includes a plurality of light emitting devices 1, each light emitting device 1 includes a planar film layer 2 and a columnar structure 3 protruding from the planar film layer 2, the display panel further includes a driving backboard 4, a pad 5 corresponding to the light emitting device 1 one to one is disposed on the driving backboard 4, the pad 5 is covered by a soft conductive structure 6, and the columnar structure 3 of the light emitting device 1 is inserted into the soft conductive structure 6 so that a metal electrode 7 wrapping the columnar structure 3 is electrically connected with the corresponding pad 5.

The light emitting device 1 may be a Micro LED, the flexible conductive structure 6 may be a metal having flexibility and good conductivity, for example, a metal material such as In, Ag, Sn, or Al, and the columnar structure 3 of the light emitting device 1 may be a solid structure or a hollow structure, where the columnar structure 3 of the light emitting device 1 is exemplarily set to be a solid structure. Specifically, with reference to fig. 1 and fig. 2, the flexible conductive structure 6 may be covered at a position where the pad 5 is disposed on the driving backplane 4, and the light emitting device 1 is disposed on the temporary substrate 40, when the light emitting device 1 is bound, the protruding columnar structure 3 of the light emitting device 1 is inserted into the flexible conductive structure 6, the columnar structure 3 is wrapped with the metal electrode 7, so that the metal electrode 7 wrapping the columnar structure 3 is electrically connected with the corresponding pad 5 on the driving backplane 4, so as to transmit a corresponding signal from the driving backplane 4 to the light emitting device 1, and the temporary substrate 40 is removed after the binding is completed.

The bonding technology adopted at present generally comprises the steps of coating welding materials with lower melting points on a chip electrode and a substrate electrode, carrying out contraposition bonding on the electrodes on two sides, heating the chip and the substrate to melt and fuse the welding materials on the two sides, and cooling to solidify the welding materials to achieve the purpose of welding. In addition, as shown in fig. 3, wafer warpage exists in the epitaxial layer of the Micro LED, and the solder on both sides of the area a1 with small warpage is already fused during the alignment bonding, but the electrodes on both sides of the area a2 with large warpage are not yet contacted, thereby affecting the bonding yield. In addition, the heating process during binding can lead to the drive backplate 4 and the temporary substrate 40 to have the problem of thermal mismatch, namely the heating leads to the drive backplate 4 and the temporary substrate 40 to produce deformation of different degrees, and then leads to the dislocation of the electrodes to be bound on both sides, further reducing the binding yield.

Specifically, with reference to fig. 1 and 2, each light emitting device 1 includes a planar film layer 2 and a columnar structure 3 protruding from the planar film layer 2, pads 5 corresponding to the light emitting devices 1 one to one are disposed on the driving backplane 4, the pads 5 are covered by the flexible conductive structures 6, the columnar structure 3 of the light emitting device 1 is inserted into the flexible conductive structures 6 so that the metal electrodes 7 including the columnar structures 3 are electrically connected with the corresponding pads 5, and thus the columnar structure 3 of the light emitting device 1 is bound with the corresponding pads 5 by inserting the flexible conductive structures 6, even if the epitaxial layer 8 of the light emitting device 1 has wafer warpage to cause the metal electrodes 7 to be separated from the corresponding pads 5, the metal electrodes 7 wrapping the columnar structure 3 can still be electrically connected with the corresponding pads 5 through the flexible conductive structures 6, thereby greatly reducing the influence of the wafer warpage on the binding yield, and the columnar structure 3 of the light emitting device 1 can be bound with the corresponding pads 5 at normal temperature by inserting the flexible conductive structures 6 And moreover, heating is not needed, and the problem that heating causes thermal mismatch and further causes binding dislocation in the binding process is effectively avoided.

Alternatively, referring to fig. 1 and fig. 2, the epitaxial layer 8 of the light emitting device 1 may wrap the columnar structure 3, and the columnar structure 3 may be an N-type semiconductor structure. Specifically, in conjunction with fig. 1 and 2, the columnar structure 3 may be, for example, an N-type GaN structure, the epitaxial layer 8 of the light emitting device 1 may include, for example, a multiple quantum well layer 81, an electron blocking layer 82, and a P-type semiconductor layer 83, and the P-type semiconductor layer 83 may be, for example, a P-type GaN layer. When the anode of the light emitting device 1, i.e., the metal electrode 7 and the cathode, receive corresponding signals, electrons in the columnar structures 3 recombine with holes in the P-type semiconductor layer 83 in the multiple quantum well layer 81 to make the light emitting device 1 emit light, and both the top surface and the side surface of the light emitting device 1 emit light.

Most of the currently adopted Micro LED structures are two-dimensional planar structures, namely, the light emitting device only comprises a planar film layer 2, in order to realize higher resolution, the light emitting device needs to be reduced to a nanometer level, at the moment, the light emitting area of the light emitting device with the two-dimensional structure is smaller, the light emitting brightness of a pixel can be greatly reduced, and the light emitting surface of the light emitting device with the two-dimensional structure is a polar surface, so that the light emitting device has a quantum confinement Taskk effect. In addition, the temporary substrate used for forming the light emitting device may be a sapphire substrate, the difference between the lattice arrangements of the epitaxial layer of the light emitting device and the sapphire substrate is large, and the epitaxial layer of the light emitting device with the two-dimensional structure and the temporary substrate have a large contact area, so that the light emitting device with the two-dimensional structure has a large dislocation density, which also affects the light emitting efficiency of the light emitting device.

Specifically, with reference to fig. 1 and fig. 2, the epitaxial layer 8 of the light emitting device 1 wraps the columnar structure 3, the columnar structure 3 is an N-type semiconductor structure, that is, the columnar structure 3 of the light emitting device 1 is arranged for emitting light, so that the light emitting device 1 forms the light emitting device 1 with a three-dimensional structure, the arrangement of the columnar structure 3 increases the light emitting area of the light emitting device 1, improves the light emitting brightness of pixels, and the light emitting surface of the light emitting device 1 provided with the columnar structure 3 is a non-polar surface and a semi-polar side surface, so that the quantum confinement tasky effect is weakened, and the light emitting efficiency of the light emitting device 1 is improved. In addition, the arrangement of the columnar structure 3 greatly reduces the contact area between the epitaxial layer 8 of the light-emitting device 1 and the temporary substrate 40, reduces the dislocation density of the light-emitting device 1, and further improves the light-emitting efficiency of the light-emitting device 1.

Optionally, with reference to fig. 1 and fig. 2, the epitaxial layer 8 of the light emitting device 1 may wrap the columnar structure 3, the columnar structure 3 may be an N-type semiconductor structure, the planar film layer 2 of the light emitting device 1 may include a mask layer 9, a plurality of via holes 10 are disposed on the mask layer 9, and the columnar structure 3 is formed at the corresponding via hole 10. Specifically, in conjunction with fig. 1 and 2, the material constituting the mask layer 9 may be SiO₂The mask layer 9 may be formed in a whole layer, via holes 10 may be etched at positions on the mask layer 9 where the pillar structures 3 are to be formed, and the via holes 10 may correspond to the mask layersThe GaN nano-pillar array is grown on the whole display panel through the via hole 10, as shown in fig. 4, the GaN nano-pillar is the columnar structure 3, so that the opening position of the mask layer 9 is easy to control, the opening position is accurate, the position of the columnar structure 3 can be accurately positioned to enable the columnar structure 3 to be formed at the central position of the light-emitting device 1, the diameter of the columnar structure 3 is directly determined by the opening diameter of the mask layer 9, and the diameter of the columnar structure 3 can be adjusted by adjusting the opening diameter of the mask layer 9, so that the light-emitting area of the light-emitting device 1 can be adjusted.

Alternatively, in combination with fig. 1, fig. 2 and fig. 4, the ratio of the height d1 of the columnar structure 3 in the direction perpendicular to the planar film layer 2 to the maximum diameter d2 of the cross section of the columnar structure 3 in the direction parallel to the planar film layer 2 may be set to be 2 or more. Specifically, with reference to fig. 1 to 4, setting the ratio of the height d1 of the columnar structure 3 along the direction perpendicular to the planar film layer 2 to the maximum diameter d2 of the cross section of the columnar structure 3 parallel to the planar film layer 2 to be greater than or equal to 2, for the columnar structure 3 with the same maximum diameter d2 of the cross section parallel to the planar film layer 2, it is beneficial to increase the height d1 of the columnar structure 3 along the direction perpendicular to the planar film layer 2, the larger the height d1 of the columnar structure 3 along the direction perpendicular to the planar film layer 2 is, when the light emitting device 1 is bonded with the driving backplate 4, the larger the margin of the portion of the columnar structure 3 contacting the soft conductive structure 6 is, the smaller the influence of the wafer warpage on the bonding yield is, so as to further improve the bonding yield of the light emitting device 1 and the driving backplate 4. In addition, the epitaxial layer 8 of the light emitting device 1 wraps the columnar structure 3, the height d1 of the columnar structure 3 in the direction perpendicular to the planar film layer 2 is larger, the area of the epitaxial layer 8 of the light emitting device 1 is larger, the area of the multiple quantum well layer 81 is larger, the light emitting area of the light emitting device is increased, and the light emitting brightness of the light emitting device 1 is improved.

Illustratively, with reference to fig. 1, fig. 2 and fig. 4, the columnar structure 3 may be a hexagonal prism with a hexagonal frustum at the top end, that is, the top surface of the columnar structure 3 is a platform of a regular hexagon, and the cross section of each place is a regular hexagon, so that the maximum diameter d2 of the cross section of the columnar structure 3 parallel to the direction of the planar film layer 2 is the diameter of the cross section of the columnar structure 3 except for the hexagonal frustum portion, that is, the maximum diagonal length of the regular hexagon. It should be noted that the specific shape of the cross section of the columnar structure 3 is not limited in the embodiment of the present invention.

Fig. 5 is a schematic cross-sectional structure diagram of another display panel according to an embodiment of the present invention, and fig. 6 is a schematic cross-sectional structure diagram of another light emitting device according to an embodiment of the present invention. Unlike the structures shown in fig. 1 and 2, in the structures shown in fig. 5 and 6, the planar film layer 2 of the light emitting device 1 includes the epitaxial layer 8 of the light emitting device 1, and the columnar structure 3 is an undoped semiconductor structure.

Specifically, referring to fig. 5 and 6, the epitaxial layer 8 of the light emitting structure may include a planar N-type semiconductor layer 15, e.g., an N-type GaN layer, a multiple quantum well layer 81, and a P-type semiconductor layer 83, e.g., a P-type GaN layer, that is, the epitaxial layer 8 of the light emitting structure, which are sequentially formed on the temporary substrate, and when the anode and the cathode of the light emitting device 1 receive corresponding signals, electrons in the planar N-type semiconductor layer 15 in the planar film layer 2 and holes in the P-type semiconductor layer 83 are recombined in the multiple quantum well layer 81 to make the light emitting device 1 emit light, and the columnar structure 3 is an undoped semiconductor layer, i.e., the columnar structure 3 does not participate in the light emission of the light emitting device 1. In addition, the planar film layer 2 of the light-emitting device 1 further includes a metal layer 84, such as an ITO layer, the metal layer 84 is in electrical contact with the metal electrode 7 to transmit an anode signal, and the planar film layer 2 further includes an insulating layer 85 wrapping a portion of the metal electrode 7 and the epitaxial layer 8.

With reference to fig. 5 and 6, the arrangement of the columnar structure 3 enables the light emitting device 1 to be bound with the corresponding pad 5 by inserting the columnar structure 3 into the soft conductive structure 6, even if the epitaxial layer 8 of the light emitting device 1 has wafer warpage to cause the metal electrode 7 to be separated from the corresponding pad 5, the metal electrode 7 wrapping the columnar structure 3 can still be electrically connected with the corresponding pad 5 through the soft conductive structure 6, the influence of the wafer warpage on the binding yield is greatly reduced, and the columnar structure 3 of the light emitting device 1 can be bound with the normal temperature corresponding to the pad 5 by inserting the soft conductive structure 6, without heating, thereby effectively avoiding the problem of binding dislocation caused by heating mismatch in the binding process.

Alternatively, with reference to fig. 5 and 6, the planar film layer 2 of the light emitting device 1 includes the epitaxial layer 8 of the light emitting device 1, the columnar structures 3 are undoped semiconductor structures, the epitaxial layer 8 of the light emitting device 1 includes a plurality of patterned epitaxial structures 80, at least one columnar structure 3 is disposed on one epitaxial structure 80, one epitaxial structure 80 and the columnar structure 3 on the epitaxial structure 80 form one light emitting device 1, fig. 5 and 6 exemplarily set one epitaxial structure 80 on which one columnar structure 3 is disposed, and then one epitaxial structure 80 and one columnar structure 3 disposed on the epitaxial structure 80 form one light emitting device 1.

Specifically, with reference to fig. 5 and 6, the planar film layer 2 of the light emitting device 1 may include a metal layer 84, such as an ITO layer, connected to the metal electrode 7 of the wrapping pillar-shaped structure 3, the planar film layer 2 of the light emitting device 1 further includes a P-type semiconductor layer 183 of the light emitting device 1, the light emitting device 1 patterns the epitaxial layer 8 to form a plurality of patterned epitaxial structures 80, such that the P-type semiconductor layer 183 and the metal layer 84 connected to the metal electrode 7 of the wrapping pillar-shaped structure 3 are disconnected according to the light emitting device 1, thereby avoiding a structural short circuit for transmitting an anode signal between different light emitting devices 1, and such that each light emitting device 1 independently receives the anode signal, so as to implement active driving of the light emitting device 1.

Fig. 7 is a schematic cross-sectional structure diagram of another display panel according to an embodiment of the invention. Different from the structures shown in fig. 5 and 6, in the display panel with the structure shown in fig. 7, one epitaxial structure 80 is provided with a plurality of columnar structures 3, for example, three columnar structures 3 are provided on one epitaxial structure 80, and then there are metal electrodes 7 wrapping the three columnar structures 3, compared with only one columnar structure 3 on one epitaxial structure 80, the contact area between one light emitting device 1 and the flexible conductive structure 6 is increased, the stability of the electrical connection between the metal electrode 7 and the corresponding bonding pad 5 is improved, and the bonding yield between the light emitting device 1 and the driving back plate 4 is further improved.

Optionally, with reference to fig. 1, fig. 2, and fig. 4 to fig. 7, an insulating layer 11 is disposed on the driving backplane 4, the insulating layer 11 forms a plurality of limiting holes b corresponding to the light emitting devices 1, and the limiting holes b are disposed with corresponding pads 5 and the flexible conductive structures 6 filled in the limiting holes b.

Specifically, in connection with fig. 1, 2, and 4 to 7, the material constituting the insulating layer 11 may be SiO₂The insulating layer 11 may be formed of a photoresist, preferably, SiO₂ The insulating layer 11 may cause that the insulating layer 11 cannot be too thick, cracks may occur in the insulating layer 11, and the insulating layer 11 is too thin or the cracks exist in the insulating layer 11 may cause the short circuit of the flexible conductive structure 6 corresponding to the adjacent light emitting device 1, thereby causing the short circuit of the structure of the adjacent light emitting device 1 for transmitting the anode signal, which affects the normal display of the display panel. In addition, the limiting hole b formed in the insulating layer 11 is also beneficial to playing a limiting role in binding the light emitting device 1, and the dislocation problem between the metal electrode 7 and the bonding pad 5 is further improved on the basis of realizing normal-temperature binding without heating to avoid the dislocation problem caused by thermal mismatch. For example, the limiting hole formed in the insulating layer may be a three-dimensional structure such as an inverted truncated cone-shaped hole, an inverted trapezoidal shape hole, an inverted triangular frustum-shaped hole, and an inverted hexagonal pyramid-shaped hole, which is not limited in the embodiment of the present invention.

Fig. 8 is a schematic cross-sectional structure diagram of another display panel according to an embodiment of the invention. Unlike the display panel with the structure shown in fig. 5, the display panel with the structure shown in fig. 8 has a plurality of ellipsoidal flexible conductive structures 6 disposed on the driving backplane 4. Specifically, as shown in fig. 8, a soft conductive material, such as a soft metal material, may be first wrapped on the pad 5 of the driving backplate 4, and after annealing, an ellipsoidal soft conductive structure 6 is formed under the action of surface tension, the columnar structure 3 of the light emitting device 1 is inserted into the soft conductive structure 6, the metal electrode 7 wrapping the columnar structure 3 is electrically connected to the corresponding pad 5 through the soft conductive structure 6, and no additional insulating layer is required to be made to form a limiting hole, so that the manufacturing process is simple, and the normal temperature binding of the light emitting device 1 and the driving backplate 4 can also be realized. In addition, the display panel with the structure shown in fig. 1 may also have a plurality of ellipsoidal flexible conductive structures 6 disposed on the driving backplate 4, and no additional insulating layer is required to form the limiting holes, which is not described herein again. In addition, fig. 8 exemplarily illustrates that the flexible conductive structure 6 is disposed in an ellipsoidal shape, and the specific shape of the flexible conductive structure 6 depends on the surface tension of the material constituting the flexible conductive structure 6, and the specific shape of the flexible conductive structure 6 is not limited in the embodiment of the present invention.

Alternatively, in combination with fig. 5 to 8, the ratio of the height d1 of the columnar structure 3 in the direction perpendicular to the planar film layer 2 to the maximum diameter d2 of the cross section of the columnar structure 3 in the direction parallel to the planar film layer 2 may be set to be 2 or more. Specifically, with reference to fig. 3 to 8, setting the ratio of the height d1 of the columnar structure 3 along the direction perpendicular to the planar film layer 2 to the maximum diameter d2 of the cross section of the columnar structure 3 parallel to the planar film layer 2 to be greater than or equal to 2, for the columnar structure 3 with the same maximum diameter d2 of the cross section parallel to the planar film layer 2, it is beneficial to increase the height d1 of the columnar structure 3 along the direction perpendicular to the planar film layer 2, the larger the height d1 of the columnar structure 3 along the direction perpendicular to the planar film layer 2 is, when the light emitting device 1 is bonded with the driving backplate 4, the larger the margin of the portion of the columnar structure 3 contacting the soft conductive structure 6 is, the smaller the influence of the wafer warpage on the bonding yield is, so as to further improve the bonding yield of the light emitting device 1 and the driving backplate 4.

Optionally, with reference to fig. 1, fig. 2, and fig. 4 to fig. 8, the ultraviolet curing glue 12 may be filled in the gap between the light emitting device 1 and the driving backplane 4 after bonding. Specifically, with reference to fig. 1, fig. 2, and fig. 4 to fig. 8, after the light emitting device 1 is bonded to the driving backplate 4, ultraviolet glue may be filled in a gap between the light emitting device 1 and the driving backplate 4 by capillary action, and the ultraviolet glue is cured by irradiation of an ultraviolet lamp, and the ultraviolet curing glue 12 is used to fixedly bond the light emitting device 1 and the driving backplate 4. The conventional method can also be used for setting a similar colloid structure, but the heating also can cause the problem that the temporary substrate 40 provided with the light-emitting device 1 and the driving backboard 4 have thermal mismatch, and the ultraviolet curing adhesive 12 is filled in the gap after the light-emitting device 1 and the driving backboard 4 are bonded, so that the problem that the heat mismatch is caused by heating and then the light-emitting device 1 and the corresponding bonding pad 5 are dislocated is avoided.

Optionally, with reference to fig. 1, fig. 2 and fig. 4 to fig. 8, the display panel may further include a plurality of reflective structures 13, and the reflective structures 13 are disposed around the epitaxial layers 8 of the corresponding light emitting devices 1 in a direction parallel to the display panel. Specifically, with reference to fig. 1 and fig. 2, each reflection structure 13 may be formed on a sidewall of a limiting hole b formed in the insulating layer 11, the epitaxial layer 8 of the light emitting device 1 wraps the columnar structure 3, and the columnar structure 3 is located in the limiting hole b, so that the reflection structure 13 can be disposed around the corresponding epitaxial layer 8 of the light emitting device 1 to reflect light emitted from the light emitting device 1 to the sidewall of the limiting hole b for display, thereby improving the light emitting efficiency of the light emitting device 1. In addition, with reference to fig. 4 to 8, each reflection structure 13 may wrap the corresponding planar film layer 2 of the light emitting device 1, that is, the reflection structure 13 is disposed around and on the lower surface of the planar film layer 2 in fig. 5 and 8 and exposes the columnar structure 3, the planar film layer 2 of the light emitting device 1 includes the epitaxial layer 8 of the light emitting device 1, that is, the reflection structure 13 may surround the epitaxial layer 8 of the corresponding light emitting device 1, the planar film layer 2 of the light emitting device 1 realizes a light emitting function, and similarly, the reflection structure 13 may reflect light emitted from the light emitting device 1 to both sides for display, thereby improving the light emitting efficiency of the light emitting device 1. The reflective structure 13 may be a metal film layer, or may be a DBR (distributed bragg reflector) or an ODR (all-directional reflector), which may improve the light emitting efficiency of the light emitting device 1.

Optionally, with reference to fig. 1, fig. 2, and fig. 4 to fig. 8, the pillar-shaped structure 3 of the light emitting device 1 is located on one side of the planar film layer 2 close to the driving back plate 4, the metal electrode 7 of the light emitting device 1 is electrically connected to the corresponding pad 5, the display panel further includes a cathode layer 14 located on one side of the light emitting device 1 away from the driving back plate 4, the planar film layer 2 of the light emitting device 1 includes a planar N-type semiconductor layer 15, the planar N-type semiconductor layer 15 is a film layer of the planar film layer 2 away from the pillar-shaped structure 3, and the planar N-type semiconductor layer 15 is electrically connected to the cathode layer 14.

Specifically, with reference to fig. 1 and fig. 2, the outermost side of the columnar structure 3 is wrapped with a metal electrode 7, such as an ITO electrode, and no metal structure is disposed in the planar film layer 2 of the light emitting device 1, so that the metal electrodes 7 between adjacent light emitting devices 1 are disconnected from each other, the driving backplane 4 includes a plurality of pixel driving circuits therein, each pad 5 is electrically connected to one pixel driving circuit, and after the light emitting device 1 and the driving backplane 4 are bound, the metal electrode 7 serves as an anode of the light emitting device 1 and receives an anode signal transmitted by the corresponding pixel driving circuit through the pad 5. In addition, the planar film layer 2 of the light emitting device 1 further includes a mask layer 9 and a planar N-type semiconductor layer 15, such as a planar N-type GaN layer, located on a side of the mask layer 9 away from the columnar structure 3, and since the planar N-type semiconductor layer 15 is not used for emitting light, the planar N-type semiconductor layer 15 may be provided as a lightly doped N-type semiconductor layer having a doping concentration less than that of the N-type semiconductor layer constituting the columnar structure 3. The planar N-type semiconductor layer 15 is electrically connected with the columnar structure 3 through the via hole 10 penetrating through the mask layer 9, the planar N-type semiconductor layer 15 of the light emitting device 1 is electrically connected with the cathode layer 14, so that the cathodes of all the light emitting devices 1 form a common layer, the N-type semiconductor layer of each light emitting device 1 receives a cathode signal transmitted by the cathode layer 14, and thus the light emitting device 1 receives corresponding anode signals and cathode signals to realize active driving.

Specifically, referring to fig. 4 to 8, the outermost side of the columnar structures 3 is wrapped with a metal electrode 7, such as an ITO electrode, the planar film layer 2 of the light emitting device 1 includes an epitaxial layer 8 of the light emitting device 1, the epitaxial layer 8 of the light emitting device 1 is patterned such that the metal electrodes 7 wrapping the respective columnar structures 3 are disconnected from each other, and the planar film layer 2 of the light emitting device 1 is also provided with the metal electrode 7, for example, an ITO electrode, the metal electrodes 7 in the planar film layer 2 are also disconnected after the epitaxial layer 8 of the light emitting device 1 is patterned, the metal electrodes 7 wrapping the columnar structure 3 and the metal layer 85 in the planar film layer 2 are electrically connected to serve as an anode of the light emitting device 1, after the light emitting device 1 is bound with the driving back plate 4, the metal electrode 7 wrapping the columnar structure 3 and the metal electrode 7 in the planar film layer 2 receive the anode signal transmitted by the corresponding pixel driving circuit through the bonding pad 5. In addition, the planar film layer 2 of the light emitting device 1 further includes a planar N-type semiconductor layer 15, the planar N-type semiconductor layer 15 forms an epitaxial layer 8 of the light emitting device 1 and is used for emitting light of the light emitting device 1, the planar N-type semiconductor layer 15 of the light emitting device 1 is electrically connected with the cathode layer 14, so that cathodes of all the light emitting devices 1 form a common layer, and the planar N-type semiconductor layer 15 of each light emitting device 1 receives a cathode signal transmitted by the cathode layer 14, so that the light emitting device 1 receives corresponding anode signals and cathode signals to realize active driving.

Alternatively, in conjunction with fig. 1, fig. 2, and fig. 4 to fig. 8, the surface of the planar N-type semiconductor layer 15 away from the columnar structure 3 may be provided with an etching pattern, where fig. 5 and fig. 8 only exemplarily illustrate that the surface of the planar N-type semiconductor layer 15 away from the columnar structure 3 has an etching pattern, and the display panel of the structure shown in fig. 1 may also be provided with the surface of the planar N-type semiconductor layer 15 away from the columnar structure 3 having an etching pattern.

Specifically, referring to fig. 1, fig. 2 and fig. 4 to fig. 8, the planar N-type semiconductor layer 15 is a film layer far from the columnar structure 3 in the planar film layer 2 of the light emitting device 1, and the planar structure of the light emitting device 1 is located on a side of the columnar structure 3 far from the driving backplane 4, that is, the planar N-type semiconductor layer 15 is a film layer located at the uppermost position of the light emitting device 1 along the light emitting direction of the light emitting device 1, and the surface of the planar N-type semiconductor layer 15 far from the columnar structure 3 is provided with an etching pattern, that is, the surface of the planar N-type semiconductor layer 15 far from the columnar structure 3 after the temporary substrate 40 is stripped is roughened, for example, the surface of the planar N-type semiconductor layer 15 far from the columnar structure 3 may be etched by wet etching or photolithography and dry etching to reduce the flatness of the surface of the planar N-type semiconductor layer 15 far from the columnar structure 3, for example, the surface of the planar N-type semiconductor layer 15 far from the columnar structure 3 may be etched to form a periodically arranged pattern And the total reflection degree of the light on the surface of the plane N-type semiconductor layer 15 away from the columnar structure 3 is reduced, and the light extraction rate of the light-emitting device 1 is improved.

Optionally, with reference to fig. 1, fig. 2, and fig. 4 to fig. 8, the light emitting function layer of the light emitting device 1 may include a multiple quantum well layer 81, and the materials of the multiple quantum well layer 81 are the same, the display panel further includes a color filter substrate 17, the color filter substrate 17 is located on one side of the light emitting device 1 away from the driving backplane 4, the color filter substrate 17 includes a plurality of color resistor units 18, and the color resistor units 18 are arranged in one-to-one correspondence with the light emitting device 1.

Specifically, with reference to fig. 1, fig. 2, and fig. 4 to fig. 8, the light emitting function layers of all the light emitting devices 1, that is, the multiple quantum well layers 81, are formed together to simplify the manufacturing process, so that the materials of the multiple quantum well layers 81 constituting all the light emitting devices 1 are the same, and the materials of the multiple quantum well layers 81 determine the light emitting colors of the corresponding light emitting devices 1, so that the light emitting colors of all the light emitting devices 1 are the same, the display panel further includes the color filter substrate 17, the color filter substrate 17 is located on the side of the light emitting devices 1 away from the driving backplane 4, for example, a black matrix 19 can be manufactured above the cathode layer 14, and the black matrix 19 is disposed corresponding to the light emitting devices 1 and serves as a dam for blocking the quantum dot ink.

The color filter substrate 17 includes a plurality of color resistance units 18, the color resistance units 18 are disposed in one-to-one correspondence with the light emitting devices 1, for example, the multiple quantum well layer 81 of all the light emitting devices 1 may be set as a blue multiple quantum well layer, then a corresponding pixel in the color filter substrate 17 may include three color resistance units 18, a quantum dot ink and a green quantum dot ink may be printed in two color resistance units 18 of the three color resistance units 18 respectively in a quantum dot printing manner, no quantum dot is disposed in another color resistance unit 18, for example, no quantum dot is disposed in the color resistance unit 181, the color resistance unit 182 is printed with the red quantum dot ink, the color resistance unit 183 is printed with the green quantum dot ink, so that the color resistance unit 181 emits blue light, the color resistance unit 182 emits red light, the color resistance unit 183 emits green light, the display panel realizes color display, and finally, the transparent cover plate 20 may be covered on the top of the display panel, the black matrix 19 in the color filter substrate 17 functions as a support for the transparent cover 20.

For example, taking the display panel with the structure shown in fig. 5 as an example, the transparent cover plate 20 coated with the quantum dots of the corresponding colors may be directly covered on the cathode layer 14, as shown in fig. 9, so that colorization of the display panel can be realized as well.

For example, referring to fig. 1, fig. 2, and fig. 4 to fig. 9, the planar film layer structure of the light emitting device may also be in a truncated cone shape, a truncated pyramid shape, a rectangular parallelepiped shape, or a square shape, which is not limited in this embodiment of the invention.

Specifically, with reference to fig. 1, fig. 2 and fig. 4, the manufacturing process of the display panel with the structure shown in fig. 1 includes:

s1, a lightly doped GaN layer, i.e., a planar N-type semiconductor layer 15, is grown on the temporary substrate 40.

S2 deposition of SiO on the planar N-type semiconductor layer 15₂Mask filmAnd (3) a layer 9.

S3 in SiO₂Coating photoresist on the mask layer 9, exposing and developing with a mask plate, and then BOE (HF acid and NH)₄F mixed solution), and finally removing the photoresist to form a porous array structure, wherein a lightly doped GaN layer, namely the planar N-type semiconductor layer 15, is exposed, and the diameter of a hole 10 is 50 nm-5 microns.

S4, growing a blue light GaN nanorod array structure at the opening, wherein the diameter is 100 nm-5 μm, and the height is 1 μm-10 μm.

S5, depositing the epitaxial layer 8 of the light emitting device 1 on the surface of the nanorod array, and forming ITO, i.e., the metal electrode 7, on the outermost surface, so far, the GaN nanorod epitaxial structure has been processed.

S6, manufacturing the driving back plate 4, wherein the diameter of the bonding pads 5 is smaller than that of the nanorods, and the center distance of the bonding pads 5 is equal to that of the nanorods and is distributed in an array.

S7, depositing a layer of SiO on the driving backboard 4₂And the thickness of the insulating layer is less than or equal to the height of the nano rod, namely the columnar structure 3.

S8, photoetching and etching process on SiO₂The insulating layer is provided with an inverted circular truncated cone hole, the bottom electrode is exposed, and the diameter of the bottom of the circular truncated cone is larger than that of the nanorod.

And S9, depositing a metal reflecting layer 13 on the side wall of the hole.

S10, filling the holes with a metal having low hardness and good conductivity, including but not limited to In, Ag, Sn, etc., and thus completing the processing of the back plate.

And S11, carrying out contraposition bonding, and inserting the GaN nanorod into the truncated cone-shaped hole.

And S12, filling transparent ultraviolet glue in the bonded gap by using capillary action, and curing the ultraviolet glue by irradiating with an ultraviolet lamp.

S13, laser lift off temporary substrate 40.

S14, a common transparent electrode, i.e. cathode layer 14, is deposited on the stripped surface.

And S15, manufacturing the color film substrate 17.

Specifically, with reference to fig. 5 and 6, the manufacturing process of the display panel with the structure shown in fig. 5 includes:

s1, the epitaxial structure 8 of the light emitting device 1 is in-situ deposited in Metal Organic Chemical Vapor Deposition (MOCVD) or Hydride Vapor Phase Epitaxy (HVPE), comprising the steps of:

and (3) baking the temporary substrate 40 at high temperature to remove surface impurities, wherein the temperature is 900-1100 ℃, and the atmosphere is mixed hydrogen and nitrogen gas or pure hydrogen gas or pure nitrogen gas.

Depositing N-type GaN, i.e., a planar N-type semiconductor layer 15, on a temporary substrate 40, the gallium sources all being TMGa and the nitrogen sources all being NH₃The ratio of V/III is 200-1000 (gas flow ratio of group V source to group III source, namely NH)₃Flow rate of (d)/flow rate of TMGa), the Si source is SiH₄The pressure of the reaction cavity is 100 mbar-500 mbar, the growth temperature is 900 ℃ -1100 ℃, and the thickness is 500 nm-3 μm.

Depositing InGaN/GaN multiple quantum well 81 on the N-type GaN, wherein the InGaN is a well layer, the In source is TMIn, the growth temperature is 500-700 ℃, the thickness is 1 nm-5 nm, the GaN is a barrier layer, the growth temperature is 700-900 ℃, and the thickness is 3-15 nm. The Ga sources of the two layers are both TMGa and the N source is both NH₃The two layers form a period, and the period of the two layers is 3-20 periods.

Depositing P-type GaN on the multiple quantum well layer 81, i.e. P-type semiconductor extraction layer 83, wherein the gallium source is TMGa, the nitrogen source is NH₃The Mg source is Cp2Mg, the growth temperature is 800-1000 ℃, and the thickness is 100 nm-1 μm.

S2, after the structure is grown, taking out the epitaxial wafer, depositing a layer of ITO (indium tin oxide), namely a metal layer 85, on the surface of the P-type GaN by adopting methods such as electron beam Evaporation (EB) or sputtering (Sputter), and annealing, wherein the thickness is 10-100 nm, the annealing temperature is 500-600 ℃, and the annealing time is 5-20 min.

S3, depositing a mask layer of SiO on the surface of ITO, i.e. the metal layer 85, by Plasma Enhanced Chemical Vapor Deposition (PECVD) or Atomic Layer Deposition (ALD)₂Or SiN_xEtc. with a thickness of 10nm to 1 μm.

S4, coating photoresist on the mask layer, exposing and developing with the mask plate, and BOE (HF acid and NH)₄Mixed solution of F) solution and ITO (indium tin oxide) etchingEtching the solution to corrode, finally removing the photoresist to form a porous array structure, exposing the P-type GaN, namely the P-type semiconductor layer 83, wherein the diameter of the hole is 10 nm-5 mu m, and the mask layer can enable the subsequent non-doped GaN nano rod to grow on the exposed part, namely the selective area, and also can protect the epitaxial layer which grows well below from being damaged in the high-temperature environment when the non-doped GaN nano rod grows.

S5, placing the structure obtained in the previous step into MOCVD or HVPE to grow the non-doped GaN nanorod structure, wherein the gallium source is TMGa, and the nitrogen source is NH₃The V/III ratio is 10-200, the pressure of the reaction cavity is 600-800 mbar, and the carrier gas is N₂The growth temperature is 900-1100 deg.C. Preferably, a pulse growth method is adopted, and a gallium source and a nitrogen source are alternately introduced into the reaction cavity: introducing TMGa for 5-50 s, pausing for 1-10 s, NH₃Introducing 5-50 s, pausing for 1-10 s, taking the four sections as a cycle, and carrying out 10-500 cycles, wherein N is in the process₂The introduction was continued. The diameter of the non-doped GaN nano rod is 10 nm-5 mu m, and the height is 100 nm-10 mu m.

And S6, removing the mask layer by using BOE solution to expose ITO, namely the metal layer 85, and heating the corrosive liquid to increase the corrosion rate.

S7, patterning the epitaxial layer, wherein the patterning comprises the following steps:

photoresist is coated on the ITO, namely the metal layer 85, and a photoetching mask plate is used to expose the area to be etched through exposure and development processes.

And patterning the ITO layer by using an ITO etching solution.

And patterning the rest epitaxial layers by adopting a dry etching technology, etching a deep channel, separating the Micro LED chips, and etching the channel to the substrate to form the separated epitaxial structure 10.

And removing the photoresist, and finishing the patterning step, wherein the non-doped GaN nanorod is positioned at the center of the Micro LED chip. The shape of the chip can be cylindrical, truncated cone, square or cuboid, and is determined by the pattern of the photoetching mask plate and the anisotropy of the dry etching technology.

S8, depositing a metal electrode 7 including but not limited to Cr/Pt/Au, Ti/Au and other alloys or Al, Au, Cu and other pure metals on the surface of the undoped GaN nanorod and the surface of the ITO, namely the metal layer 85.

Further, steps S7 and S8 may be replaced with the following steps:

s7', metal electrode 7 is deposited on the whole surface of the epitaxial layer by EB or Sputter method, including the surface of the non-doped GaN nano rod and the surface of the ITO metal layer 85.

S8', the epitaxial layer is patterned, and the method comprises the following steps:

and coating photoresist on the metal, and exposing and developing the channel region to be etched by using a photoetching mask plate.

And etching the metal in the channel region by using a dry etching technology, wherein the specific metal can also be corroded by using a specific metal corrosive liquid.

And etching the channel ITO by using an ITO etching solution.

And patterning the rest epitaxial layers by adopting a dry etching technology, etching a deep channel, separating the Micro LED chip, and etching the substrate in the channel.

And removing the photoresist, and finishing the patterning step, wherein the non-doped GaN nanorod is positioned at the center of the Micro LED chip.

S9, depositing a passivation layer, such as SiO on the side wall of the LED chip and the upper surface of the two-dimensional epitaxial layer by PECVD or ALD₂The thickness is 50 nm-500 nm.

S10, evaporating DBR structure, such as SiO, on the surface of the passivation layer by ion beam sputtering₂/TiO₂、 MgF/ZrO₂And the two layers form a period, and evaporation is carried out for 3-50 periods.

S11, manufacturing a driving backboard 4, wherein a CMOS or TFT circuit is arranged in the backboard, bonding pads 5 are led out to the surface of the driving backboard 4 and distributed in an array mode, the distance between the bonding pads 5 is equal to the structure of the non-doped GaN nanorod array, and the diameter of each bonding pad 5 is smaller than or equal to that of the non-doped GaN nanorod.

S12, spin-coating a layer of flat photoresist on the backboard, wherein the thickness of the photoresist is less than or equal to the height of the non-doped GaN nanorod

And S13, carrying out photoetching, and developing to form holes which are distributed in an array form, namely limiting holes b, exposing the bottom electrode, wherein the holes can be in the shapes of a cylinder, an inverted truncated cone, a quadrangular prism and a hexagonal prism, and the diameter is larger than that of the undoped GaN nanorod.

S14, filling the holes with soft and good conductive metal including but not limited to In, Ag, Sn, Al, etc., wherein the filling amount of the metal is less than the difference between the volume of the holes and the volume of the non-doped GaN nanorods, so as to avoid short circuit caused by metal overflow during binding, and thus, the processing of the back plate is completed.

And S15, carrying out para-position bonding, and inserting the non-doped GaN nanorod into the hole of the backboard. Due to the fact that wafer warping exists in the epitaxial layer, the depth of the non-doped GaN nanorods inserted into the holes in each area is different, but the insertion depth has no influence on the display effect, and the non-doped GaN nanorods only contact with soft metal in the holes, so that the influence of wafer warping can be relieved.

And S16, filling ultraviolet glue in the bonded gap by using capillary action, and curing the ultraviolet glue by irradiating with an ultraviolet lamp. The ultraviolet glue has an insulating effect, can be transparent or opaque, has good viscosity, and can tightly adhere the epitaxial layer 8 and the driving back plate 4.

S17, peeling off the temporary substrate 40. For the sapphire substrate, a laser stripping technology can be adopted, the ultraviolet glue can play a supporting role, the stripping yield is improved, and for the silicon substrate, wet etching can be adopted, and at the moment, the ultraviolet glue needs to have the characteristic of corrosion resistance.

And S18, roughening the exposed N-type GaN surface after the substrate is stripped, and improving the light extraction efficiency. The surface of the N-type GaN can be randomly coarsened by adopting a wet etching method, and the surface of the N-type GaN can be etched into a periodically arranged pattern by adopting photoetching and dry etching.

S19, depositing a layer of ITO on the roughened N-type GaN surface by adopting methods such as electron beam Evaporation (EB) or sputtering (Sputter) to serve as a common transparent electrode, namely the cathode layer 14, and annealing, wherein the thickness is 10-100 nm, the annealing temperature is 500-600 ℃, and the annealing time is 5-20 min. The cathode layer 14 includes, but is not limited to, ITO, FTO (fluorine doped SnO)₂) AZO (Al-doped)ZnO) may be used.

S20, a black matrix 19 is formed on the cathode layer 14 by photolithography to separate the Micro LED chips as a barrier for the quantum dot ink. The method is characterized in that three Micro LEDs are used as a unit, red and green quantum dot ink is printed above two Micro LED chips of each unit to realize colorized display, and finally a transparent cover plate 20 covers the upper part of the unit, and the black matrix 19 plays a supporting role. Alternatively, as shown in fig. 9, a transparent cover plate 20 coated with red and green quantum dots may be directly covered over the cathode layer 14.

Specifically, the manufacturing process of the display panel having the structure shown in fig. 8 steps S11 to S13 in the manufacturing process of the display panel having the structure shown in fig. 5 are replaced as follows:

s11', a soft metal is wrapped on the pad 5 of the driving backplate 4, and after annealing, the metal is in an ellipsoidal shape under the action of surface tension, i.e. the soft conductive structure 6.

And S12', carrying out para-position bonding, and inserting the non-doped GaN nanorod into the soft conductive structure 6.

S13', filling ultraviolet glue in the bonded gap by capillary action, and curing the ultraviolet glue by ultraviolet lamp irradiation.

It should be noted that the drawings of the embodiments of the present invention only show the sizes of the elements by way of example, and do not represent the actual sizes of the elements in the display panel.

An embodiment of the present invention further provides a display device, and fig. 10 is a schematic structural diagram of the display device provided in the embodiment of the present invention. As shown in fig. 10, the display device 200 includes the display panel 190 of the above embodiment, and thus the display device 200 provided in the embodiment of the present invention also has the beneficial effects described in the above embodiment, which are not repeated herein. For example, the display device may be a mobile phone, or may be an electronic device such as a computer or a wearable device, and the embodiment of the present invention does not limit the specific form of the display device.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments illustrated herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A display panel, comprising:

the driving back plate is provided with bonding pads in one-to-one correspondence with the light-emitting devices, the bonding pads are covered by the soft conductive structures, the soft conductive structures are made of metal, the columnar structures of the light-emitting devices are inserted into the soft conductive structures so that the metal electrodes of the columnar structures are wrapped with the corresponding bonding pads to be electrically connected, and the light-emitting devices and the driving back plate are bound at normal temperature.

2. The display panel according to claim 1, wherein an epitaxial layer of the light emitting device wraps the columnar structure and the columnar structure is an N-type semiconductor structure; or, the planar film layer of the light-emitting device comprises an epitaxial layer of the light-emitting device and the columnar structure is an undoped semiconductor structure.

3. The display panel according to claim 1, wherein the columnar structure is wrapped by an epitaxial layer of the light emitting device and is an N-type semiconductor structure, the planar film layer of the light emitting device comprises a mask layer, a plurality of via holes are formed in the mask layer, and the columnar structure is formed at the corresponding via hole.

4. The display panel of claim 1, wherein the planar film layer of the light emitting device comprises an epitaxial layer of the light emitting device and the columnar structures are undoped semiconductor structures, the epitaxial layer comprises a plurality of patterned epitaxial structures, at least one of the columnar structures is disposed on one of the epitaxial structures, and one of the epitaxial structures and the columnar structure on the epitaxial structure constitute one of the light emitting devices.

5. The display panel according to any one of claims 1 to 4, wherein an insulating layer is disposed on the driving backplane, a plurality of limiting holes are formed in the insulating layer corresponding to the light emitting devices, and the limiting holes are disposed with the corresponding bonding pads and the flexible conductive structures filled in the limiting holes.

6. The display panel according to any one of claims 1 to 4, wherein a gap between the light emitting device and the driving backplane after bonding is filled with an ultraviolet curing adhesive.

7. The display panel according to any one of claims 1 to 4, further comprising:

8. The display panel according to any one of claims 1 to 4, wherein the columnar structure of the light emitting device is located on a side of the planar film layer adjacent to the driving backplane, and the metal electrode of the light emitting device is electrically connected to the corresponding bonding pad;

9. The display panel according to any one of claims 1 to 4, wherein the ratio of the height of the columnar structure in the direction perpendicular to the plane film layer to the maximum diameter of the cross section of the columnar structure in the direction parallel to the plane film layer is 2 or more.

10. A display device characterized by comprising the display panel according to any one of claims 1 to 9.