Display device

Abstract

The invention discloses a display device and a manufacturing method thereof, the display device comprises a driving backboard and a plurality of display units located on the driving backboard, and each display unit comprises a carrier plate; the carrier plate comprises a plurality of bonding pads; at least two light-emitting chips, wherein the colors of emergent light of the light-emitting chips are different; one light-emitting chip is positioned on one bonding pad and is electrically connected with the bonding pad; the common electrode is positioned on one bonding pad and is electrically connected with the bonding pad; the side, away from the carrier plate, of each light-emitting chip is connected to the common electrode. The light-emitting chip in the display unit is of a vertical structure, the light-emitting area proportion is higher, a smaller chip can be used under the same brightness requirement, and the chip cost is reduced. Only one electrode is arranged at the bottom of the light-emitting chip, and the size of the electrode is the same as that of the light-emitting chip, so that a series of risks such as short circuit and metal migration caused by too small electrode distance are reduced. The light-emitting chip adopting the vertical structure is larger in heat conduction area and lower in thermal resistance.

Description

Technical Field

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

[0002] Light Emitting Diode (LED) display technology refers to the display technology that uses LED directly as the light-emitting unit. As the requirements for the resolution and display effect of display devices become higher and higher, LED display devices usually use Mini LED (Mini Light Emitting Diode, Mini LED for short) chips or Micro LED (Micro Light Emitting Diode, Micro LED for short) chips as the light-emitting unit.

[0003] At present, the mainstream way to package Mini LED chips or Micro LED chips is MIP (Micro / Mini LED in Package). In the currently mass-produced MIP packaging structure, Mini LED chips or Micro LED chips are arranged in parallel, and the parallel light-emitting chips use flip chips. Due to the limitations of current technology, the reduction in the distance between the two pads on the circuit board used to solder the flip chip is limited, resulting in the inability to further reduce the size of the flip chip and the packaging structure. As the distance between the two electrodes of the flip chip continues to decrease, there are reliability risks such as metal migration. In addition, in order to match the circuit of multiple flip chips, the packaging unit needs to be routed and punched, and the thermal resistance of the entire packaging unit will increase. Summary of the invention

[0004] According to a first aspect of an embodiment of the present invention, a display device is provided, including:

[0005] A driving backplane, used for providing a driving signal; and

[0006] A plurality of display units are located on the driving backplane, and the plurality of display units are electrically connected to the driving backplane respectively;

[0007] Wherein, the display unit comprises:

[0008] A carrier board; the carrier board comprises a plurality of pads;

[0009] at least two light-emitting chips, each of which emits light of different colors; one of the light-emitting chips is located on one of the pads and is electrically connected to the pad; and

[0010] A common electrode is located on one of the pads and electrically connected to the pad; a side of each of the light-emitting chips facing away from the carrier is connected to the common electrode.

[0011] In some embodiments of the present invention, the light emitting chip comprises:

[0012] substrate;

[0013] A first electrode is located between the substrate and the carrier; the first electrode is electrically connected to the corresponding pad on the carrier;

[0014] a bonding layer, located on a side of the substrate facing away from the first electrode;

[0015] A first semiconductor layer, located on a side of the bonding layer facing away from the substrate;

[0016] A light emitting layer, located on a side of the first semiconductor layer away from the bonding layer;

[0017] A second semiconductor layer is located on a side of the light emitting layer away from the first semiconductor layer; and

[0018] The second electrode is located on a side of the second semiconductor layer away from the light-emitting layer; the second electrode is electrically connected to the common electrode.

[0019] In some embodiments of the present invention, the orthographic projections of the first semiconductor layer, the light-emitting layer, and the second semiconductor layer in the light-emitting chip on the substrate are located within the orthographic projection of the bonding layer on the substrate, and the orthographic projection of the second electrode on the substrate is located within the orthographic projection of the second semiconductor layer on the substrate; the edges of the bonding layer, the first semiconductor layer, the light-emitting layer, the second semiconductor layer, and the second electrode are stepped;

[0020] The light emitting chip further comprises:

[0021] The insulating layer covers the stepped edges of the bonding layer, the first semiconductor layer, the light-emitting layer and the second semiconductor layer and exposes the second electrode; the surface of the second electrode facing away from the substrate is higher than the surface of the insulating layer facing away from the substrate.

[0022] In some embodiments of the present invention, the bonding layer is made of metal material, and the substrate is made of silicon.

[0023] In some embodiments of the present invention, the display unit further includes:

[0024] An encapsulation layer filled between each of the light-emitting chips and the common electrode; the encapsulation layer exposes the second electrode of each of the light-emitting chips and a portion of the common electrode;

[0025] a conductive layer, covering each of the second electrodes and the common electrode exposed by the encapsulation layer; and

[0026] The protection layer is located on a side of the conductive layer away from the packaging layer.

[0027] In some embodiments of the present invention, the encapsulation layer includes a first encapsulation layer and a second encapsulation layer; the first encapsulation layer is located between the second encapsulation layer and the carrier;

[0028] The first encapsulation layer is doped with dark material; the second encapsulation layer is doped with light diffusion material.

[0029] In some embodiments of the present invention, a surface of the first packaging layer facing away from the carrier is flush with a surface of the substrate facing away from the carrier.

[0030] In some embodiments of the present invention, the carrier includes a plurality of through holes corresponding one-to-one to the plurality of pads;

[0031] The pads include a first pad and a second pad, the first pad is located on a side of the carrier facing the driving backplane, the second pad is located on a side of the carrier away from the driving backplane, and the first pad and the second pad are electrically connected through the corresponding through holes.

[0032] According to a second aspect of an embodiment of the present invention, a method for manufacturing a display device is provided, comprising:

[0033] forming a plurality of pads on a carrier board;

[0034] forming a plurality of common electrodes on a plurality of pads of the carrier;

[0035] Transferring a plurality of light-emitting chips to the pads of the carrier and electrically connecting them to the corresponding pads;

[0036] Encapsulating each of the light-emitting chips so that the encapsulation layer exposes a portion of the second electrode of each of the light-emitting chips and each of the common electrodes;

[0037] forming a conductive layer on the packaging layer;

[0038] forming a protective layer on the conductive layer to form a display unit structure plate;

[0039] Cutting the display unit structural plate to form a plurality of display units;

[0040] Each of the display units is transferred to a driving backplane and electrically connected to the driving backplane.

[0041] In some embodiments of the present invention, the step of packaging each of the light-emitting chips comprises:

[0042] A first encapsulation layer is formed between each of the light-emitting chips and each of the common electrodes on the carrier; the first encapsulation layer is doped with a dark material, and a surface of the first encapsulation layer facing away from the carrier is flush with a surface of the substrate of the light-emitting chip facing away from the carrier;

[0043] A second encapsulation layer is formed on the first encapsulation layer; the second encapsulation layer is doped with a light diffusion material, and the second encapsulation layer exposes a portion of the second electrode of each of the light-emitting chips and each of the common electrodes.

[0044] In the display device and manufacturing method provided by the embodiment of the present invention, the display device includes a driving backplane and a plurality of display units located on the driving backplane, and the display unit includes: a carrier; the carrier includes a plurality of pads; at least two light-emitting chips, each light-emitting chip has a different color of emitted light; a light-emitting chip is located on a pad and electrically connected to the pad; a common electrode is located on a pad and electrically connected to the pad; the side of each light-emitting chip facing away from the carrier is connected to the common electrode. The light-emitting chip in the display unit adopts a vertical structure, and the light-emitting area accounts for a higher proportion. Smaller chips can be used under the same brightness requirements, and the chip cost is reduced. There is only one electrode at the bottom of the light-emitting chip and its size is the same as that of the light-emitting chip, thereby reducing a series of risks such as short circuit and metal migration caused by too small an electrode spacing. The light-emitting chip with a vertical structure has a larger thermal conductivity area and lower thermal resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings introduced below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0046] Figure 1 It is a structural schematic diagram of a MIP packaging structure in the related art;

[0047] Figure 2 It is a schematic diagram of the cross-sectional structure of a flip chip in the related art;

[0048] Figure 3 A schematic diagram of the planar structure of a display device provided by an embodiment of the present invention;

[0049] Figure 4 A schematic diagram of a cross-sectional structure of a display device provided by an embodiment of the present invention;

[0050] Figure 5 One of the structural schematic diagrams of the display unit provided by the embodiment of the present invention;

[0051] Figure 6A schematic diagram of the planar structure of a carrier provided in an embodiment of the present invention;

[0052] Figure 7 A schematic diagram of the cross-sectional structure of a carrier provided in an embodiment of the present invention;

[0053] Figure 8 A schematic diagram of the cross-sectional structure of a light-emitting chip provided in an embodiment of the present invention;

[0054] Fig. 9 A second structural schematic diagram of a display unit provided in an embodiment of the present invention;

[0055] Fig.10 A flow chart of a method for manufacturing a display device provided by an embodiment of the present invention;

[0056] Fig.11 A third structural schematic diagram of a display unit provided in an embodiment of the present invention;

[0057] Fig.12 The fourth structural schematic diagram of the display unit provided in the embodiment of the present invention. DETAILED DESCRIPTION

[0058] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described below with reference to the accompanying drawings and examples. However, the exemplary embodiments can be implemented in various forms and should not be understood as being limited to the embodiments described herein; on the contrary, these embodiments are provided to make the present invention more comprehensive and complete, and to fully convey the concepts of the exemplary embodiments to those skilled in the art. The same figure marks in the figures represent the same or similar structures, and thus their repeated descriptions will be omitted. The words expressing position and direction described in the present invention are all explained using the accompanying drawings as examples, but changes can be made as needed, and the changes made are all included in the scope of protection of the present invention. The drawings of the present invention are only used to illustrate the relative position relationship and do not represent the true proportions.

[0059] Light Emitting Diode (LED) display technology refers to the display technology that uses LED directly as the light-emitting unit. Mini LED (Mini Light Emitting Diode, Mini LED for short) chip or Micro LED (Micro Light Emitting Diode, Micro LED for short) chip is a miniaturized LED chip, and its size can reach the micron level. For example, the size of Mini LED chip is less than 500μm, and the size of Micro LED is less than 100μm. When the size of LED chip is reduced to pixel level, Mini LED or Micro LED can be directly used as the light-emitting unit for image display.

[0060] Because Mini LED and Micro LED have the characteristics of low power consumption, long life, high stability, and self-luminescence without the need for a backlight, they have the advantages of energy saving and high integration. They can be applied to almost all mainstream display fields and are considered to be the ideal form of future display technology.

[0061] Current Mini LED or Micro LED display devices usually require the driver backplane and Mini LED, Micro LED to be manufactured separately, and then use mass transfer technology to transfer the Mini LED, Micro LED to the driver backplane for assembly, resulting in a low production yield.

[0062] In order to overcome the above problems, multiple Mini LED chips or Micro LED chips can be packaged into a packaging unit first, and then the packaging unit can be transferred to the driver backplane to reduce the number of transfers. LED packaging has evolved from dual in-line package (DIP), plastic leaded chip carrier (PLCC), top-emitting surface mount devices (SMD), chip type SMD, matrix integrated package (IMD), chip on board package (COB) to the current mainstream microchip package (Micro / Mini LED in Package, MIP).

[0063] Figure 1 is a schematic diagram of the structure of the MIP packaging structure in the related art, Figure 2 It is a schematic diagram of the cross-sectional structure of a flip chip in the related art.

[0064] like Figure 1 and Figure 2 As shown, the light emitting chip 22 in the currently mass-produced MIP packaging structure is usually a flip chip, and a MIP packaging structure includes a plurality of light emitting chips 22 arranged in parallel. For a flip chip, each light emitting chip needs to be provided with two pads for connecting the two electrodes of the light emitting chip ( Figure 2 The first electrode e1 and the second electrode e2 in the circuit board are shown in FIG. 1 ). Due to the current technology, the distance between the two pads for soldering the flip chip on the circuit board is limited, resulting in the inability to further reduce the size of the flip chip and the size of the packaging structure. As the distance between the two electrodes of the flip chip is reduced, there are reliability risks such as metal migration. In addition, in order to match the circuits of multiple flip chips, the packaging structure needs to be routed and punched, and the thermal resistance of the entire packaging structure will increase.

[0065] In view of this, an embodiment of the present invention provides a display device. Figure 3 A schematic diagram of the planar structure of a display device provided in an embodiment of the present invention, Figure 4 A schematic cross-sectional structure diagram of a display device provided by an embodiment of the present invention.

[0066] like Figure 3 and Figure 4 As shown, the display device includes: a driving backplane 1 and a plurality of display units 2.

[0067] The driving backplane 1 is located at the bottom of the display device. Usually, its size is adapted to the overall size of the display device, and the size of the driving backplane 1 is slightly smaller than the size of the display device.

[0068] The shape of the driving backplane 1 is the same as the overall shape of the display device, and can be set to a rectangular or square shape in general. When the display device is a special-shaped display device, the shape of the driving backplane can be adaptively set to other shapes, which is not limited here.

[0069] The driving backplane 1 can be manufactured using the currently mature thin film process, and the driving backplane 1 can be manufactured as an active driving backplane. Alternatively, the driving backplane 1 can also use a printed circuit board (PCB), for example, a high density interconnect (HDI) circuit board.

[0070] In some embodiments, the display device may also include multiple driving backplanes 1, which are spliced ​​to provide driving signals for the display device. In order to avoid optical problems caused by splicing driving backplanes 1, the seams between adjacent driving backplanes 1 are minimized, or even seamless splicing is achieved.

[0071] The driving backplane 1 is used to provide a driving signal, and the display unit 2 is located on the driving backplane 1 and is electrically connected to the driving backplane 1. The display unit 2 is a pixel for image display, and at least two light-emitting chips can be packaged using MIP packaging technology as the display unit 2. In order to achieve full-color display, the display unit 2 can include three light-emitting chips, namely a red chip, a green chip, and a blue chip.

[0072] Figure 5 One of the structural schematic diagrams of the display unit provided by the embodiment of the present invention; Figure 6 A schematic diagram of the planar structure of a carrier provided in an embodiment of the present invention; Figure 7 A schematic diagram of the cross-sectional structure of a carrier provided in an embodiment of the present invention.

[0073] like Figure 5As shown, the display unit 2 includes: a carrier board 21 , at least two light emitting chips 22 and a common electrode 23 .

[0074] Specifically, if Figure 6 and Figure 7 As shown, the carrier 21 is used to carry the light emitting chip 22 and the common electrode 23, and also serves as a substrate of the MIP packaging structure. Generally, the carrier 21 is rectangular or square, which is not limited here.

[0075] The carrier 21 includes a plurality of pads p for electrically connecting to the light emitting chip 22 and the common electrode 23. In a specific implementation, a display unit may include three light emitting chips and one common electrode; the three light emitting chips are used to emit red light, green light, and blue light, respectively. Accordingly, four pads p may be provided on the carrier 21, three of which are used to provide the three light emitting chips 22, and another pad is used to provide the common electrode 23. The pads may be arranged as follows: Figure 6 In the two rows and two columns shown, the arrangement order of the light emitting chips 22 and the common electrodes 23 can be set as required and is not limited here.

[0076] The pads p on the carrier are not only used to electrically connect to the light emitting chip 22 and the common electrode 23, but also used to electrically connect to the driving backplane 1. Figure 7 As shown, the carrier also includes a plurality of through holes h corresponding to the plurality of pads p one by one; the pads p include a first pad p1 and a second pad p2, the first pad p1 is located on the side of the carrier facing the driving backplane, the second pad p2 is located on the side of the carrier away from the driving backplane, and the first pad p1 and the second pad p2 are electrically connected through the corresponding through holes h. Thus, the first pad p1 is electrically connected to the driving backplane 1, and the second pad p2 is electrically connected to the light emitting chip 22 and the common electrode 23, so that the circuit connection between the driving backplane and the display unit is realized, and the luminous brightness of the display unit is controlled by the driving backplane.

[0077] like Figure 5 As shown, each display unit includes at least two light emitting chips 22, and the light emitted by each light emitting chip 22 has different colors. For example, each display unit may include three light emitting chips 22 for emitting three primary color lights, so that one display unit can be used as a pixel.

[0078] The substrate 21 is provided with pads p corresponding to each light emitting chip 22, and each light emitting chip 22 is located on and electrically connected to the corresponding pad p. At the same time, another pad p is provided on the substrate 21 for providing a common electrode 23, and the common electrode 23 is located on and electrically connected to the corresponding pad p.

[0079] Figure 8 A schematic diagram of the cross-sectional structure of a light-emitting chip provided in an embodiment of the present invention.

[0080] like Figure 8 As shown, the light emitting chip includes: a substrate 221, a bonding layer 222, a first semiconductor layer 223, a light emitting layer 224, a second semiconductor layer 225, an insulating layer 226, a first electrode e1 and a second electrode e2.

[0081] In the embodiment of the present invention, the light-emitting chip 23 adopts a vertical chip, and the electrodes of the vertical chip are located at both ends of the chip, wherein the electrode on one side is connected to the pad p on the carrier, and the electrode on the other side is connected to the common electrode 23, thereby realizing the common electrode setting of multiple light-emitting chips 23. The light-emitting chip of the display unit in the embodiment of the present invention adopts a vertical structure. Compared with the traditional upright structure, the electrode can be smaller, the light-emitting area accounts for a higher proportion, and a smaller chip can be used under the same brightness requirement, and the chip cost is reduced; at the same time, the wire bonding process is omitted, and a series of risks such as solder joint detachment and wire breakage caused by the wire bonding are eliminated. Compared with the traditional flip-chip structure, there is only one electrode at the bottom and the size is the same as the light-emitting chip, so a series of risks such as short circuit and metal migration caused by too small electrode spacing are reduced; and the light-emitting chip with a vertical structure has a larger thermal conductivity area and lower thermal resistance. The pad in the display unit directly contacts the light-emitting chip and the common electrode through a through hole, so the internal circuit of the carrier is omitted, the heat dissipation path is shortened, and the thermal resistance is lower; and the carrier adopts a through-hole design, which reduces the deposition line routing, and the cost is relatively reduced.

[0082] Specifically, if Figure 8 As shown, the first electrode e1 is located between the substrate 221 and the carrier 21, and the first electrode e1 is electrically connected to the corresponding pad p on the carrier 21; the bonding layer 222 is located on the side of the substrate 221 away from the first electrode e1; the first semiconductor layer 223 is located on the side of the bonding layer 222 away from the substrate 221; the light-emitting layer 224 is located on the side of the first semiconductor layer 223 away from the bonding layer 222; the second semiconductor layer 225 is located on the side of the light-emitting layer 224 away from the first semiconductor layer 223; the second electrode e2 is located on the side of the second semiconductor layer 225 away from the light-emitting layer 224, and the second electrode e2 is electrically connected to the common electrode 23.

[0083] In the embodiment of the present invention, each light-emitting chip 22 in the display unit can be a Mini LED chip or a Micro LED chip. The Mini LED chip or the Micro LED chip can be manufactured by a vapor deposition method. The first semiconductor layer 223 can be a P-type doped semiconductor layer, the second semiconductor layer 225 can be an N-type doped semiconductor layer, and the light-emitting layer 224 can be a multiple quantum well (MQW) light-emitting layer.

[0084] The materials used in the light-emitting chips that emit light of different colors are also different. Among them, the light-emitting layer of the green light chip can be made of compound materials such as indium gallium nitride (InGaN), gallium nitride (GaN), gallium phosphide (GaP), aluminum gallium indium phosphide (AlGaInP), and aluminum gallium phosphide (AlGaP). The light-emitting layer of the blue light chip can be made of compound materials such as gallium nitride (GaN), indium gallium nitride (InGaN), and zinc arsenide (ZnSe). The light-emitting layer of the red light chip can be made of compound materials such as aluminum gallium arsenide (AlGaAs), gallium arsenic phosphide (GaAsP), aluminum gallium indium phosphide (AlGaInP), gallium phosphide (GaP), and indium gallium nitride (InGaN).

[0085] It is worth noting that the substrate 221 of the light emitting chip 22 is not the growth substrate when the light emitting chip is manufactured, but the growth substrate is peeled off after the epitaxial structure is manufactured in the manufacturing process, and the conductive substrate 221 is bonded, and the bonding layer 222 is used to connect the epitaxial structure of the light emitting chip with the conductive substrate 221, so that the first electrode e1 can be formed on the side of the substrate 221 away from the bonding layer 222. In a specific implementation, the bonding layer 222 can be made of a bonding material such as metal, and the substrate 221 can be made of a conductive material such as silicon, which is not limited here.

[0086] like Figure 8 As shown, the orthographic projections of the first semiconductor layer 223, the light-emitting layer 224, and the second semiconductor layer 225 in the light-emitting chip on the substrate 221 are located within the orthographic projection of the bonding layer 222 on the substrate 221, and the orthographic projection of the second electrode e2 on the substrate 221 is located within the orthographic projection of the second semiconductor layer 225 on the substrate 221, that is, the size of the first semiconductor layer 223, the light-emitting layer 224, and the second semiconductor layer 225 is smaller than the size of the bonding layer 222, and the size of the second electrode e2 is smaller than the size of the second semiconductor layer 225, so that the edges of the bonding layer 222, the first semiconductor layer 223, the light-emitting layer 224, the second semiconductor layer 225, and the second electrode e2 are in a stepped shape. The insulating layer 226 covers the edges of the bonding layer 222, the first semiconductor layer 223, the light-emitting layer 224, and the second semiconductor layer 225 in a stepped shape and exposes the second electrode e2, so that the surface of the second electrode e2 on the side facing away from the substrate 221 is higher than the surface of the insulating layer 226 on the side facing away from the substrate 221. The insulating layer 226 covers the edges of the first semiconductor layer 223, the light-emitting layer 224, and the second semiconductor layer 225 to provide insulation protection for the light-emitting chip. The insulating layer 226 can be made of insulating materials such as silicon dioxide. The light emitted from the light-emitting layer 224 is emitted from the side through the insulating layer 226, thereby improving the utilization rate of the light emitted from the light-emitting layer 224.

[0087] Fig. 9 The second structural schematic diagram of the display unit provided in the embodiment of the present invention.

[0088] like Fig. 9 As shown, the display unit further includes: an encapsulation layer 24 , a conductive layer 25 and a protective layer 26 .

[0089] The encapsulation layer 24 is filled between each light emitting chip 22 and the common electrode 23 to encapsulate and protect the light emitting chip. The encapsulation layer 24 needs to expose the second electrode e2 of each light emitting chip 22 and the top area of ​​the common electrode 23 .

[0090] The conductive layer 25 covers the second electrodes e2 and the common electrode 23 exposed by the encapsulation layer 24, so that the second electrodes e2 and the common electrode 23 are electrically connected to form a common electrode structure. Generally, the first electrode e1 of the light-emitting chip is a P electrode, and the second electrode e2 is an N electrode, so the display unit and each light-emitting chip 22 can form a common N electrode structure.

[0091] The protection layer 26 is located on a side of the conductive layer 25 away from the encapsulation layer 24 , and is used to provide insulation protection for the conductive layer 25 .

[0092] In a specific implementation, the electrodes of the light-emitting chip 22 can be made of metal materials, the common electrode 23 can be made of metal materials or transparent conductive materials, and the conductive layer 25 needs to be made of transparent conductive materials. The specific materials used for the electrodes of the light-emitting chip 22, the common electrode 23 and the conductive layer 25 are not limited herein.

[0093] In some embodiments, Fig. 9 As shown, the encapsulation layer 24 includes a first encapsulation layer 241 and a second encapsulation layer 242; the first encapsulation layer 241 is located between the second encapsulation layer 242 and the carrier 21, and the first encapsulation layer 241 is arranged closer to one side of the carrier 21. The first encapsulation layer 241 and the second encapsulation layer 242 can both be made of epoxy resin, silicone resin, modified resin of epoxy resin or modified resin of silicone resin. Among them, the dark material (such as carbon black or dye) in the first encapsulation layer 241 makes the first encapsulation layer 241 black; the second encapsulation layer 242 is doped with a light diffusion material, so that the second encapsulation layer 242 has a light diffusion performance. Setting the first encapsulation layer 241 to black can make the display units have the same background color, avoiding the problem of inconsistent display caused by the color difference of the carrier. At the same time, setting the first encapsulation layer 241 to black can also improve the contrast of the display unit. Doping the light diffusion material in the second encapsulation layer 242 can homogenize the output light of the light-emitting chip, avoiding the problem of inconsistent display when viewing the display device at a large angle.

[0094] In the embodiment of the present invention, the surface of the first encapsulation layer 241 facing away from the carrier 21 is flush with the surface of the substrate 221 of the light emitting chip facing away from the carrier 21. Thus, the first encapsulation layer 241 is kept at a certain distance from the light emitting layer of the light emitting chip, thereby avoiding the brightness loss caused by the first encapsulation layer 241 absorbing the emitted light of the light emitting chip.

[0095] For a flip chip, the light-emitting layer is only about 10um away from the light-emitting chip. If a black encapsulation layer like the first encapsulation layer 241 is used, it will absorb a large amount of the emitted light from the light-emitting chip, resulting in excessive light loss. Therefore, the blackness of the black encapsulation layer has to be reduced, which will result in low contrast and poor ink color consistency. If the concentration of the black encapsulation layer is too low, it will lead to uneven distribution and large mixing errors. In an embodiment of the present invention, the light-emitting chip adopts a vertical structure, the light-emitting layer is above the light-emitting chip, and the black encapsulation layer is located at the bottom of the encapsulation structure. Therefore, the color of the black encapsulation layer can be darker, with higher contrast and better ink color consistency.

[0096] In addition, the second encapsulation layer 242 needs to expose the second electrode e2 of each light-emitting chip 22 and the top of the common electrode 23, so that when the conductive layer 25 is formed, the conductive layer can contact the second electrode e2 of each light-emitting chip 22 and the top of the common electrode 23 to form a common electrode structure.

[0097] Another aspect of the embodiments of the present invention further provides a method for manufacturing a display device. Fig.10 The present invention provides a flowchart of a method for manufacturing a display device according to an embodiment of the present invention.

[0098] like Fig.10 As shown, a method for manufacturing a display device includes:

[0099] S10, forming a plurality of pads on the carrier;

[0100] S20, forming a plurality of common electrodes on a plurality of pads of the carrier;

[0101] S30, transferring the plurality of light-emitting chips to the pads of the carrier and electrically connecting the plurality of light-emitting chips to the corresponding pads;

[0102] S40, encapsulating each light-emitting chip so that the encapsulation layer exposes a portion of the second electrode of each light-emitting chip and each common electrode;

[0103] S50, forming a conductive layer on the packaging layer;

[0104] S60, forming a protective layer on the conductive layer to form a display unit structure plate;

[0105] S70, cutting the display unit structural plate to form a plurality of display units;

[0106] S80, transferring each display unit to the driving backplane and electrically connecting the driving backplane.

[0107] The manufacturing method of the display device provided by the present invention requires that the driving backplane and the display unit are manufactured separately, and then the display unit is transferred to the driving backplane and electrically connected to the driving backplane. The driving backplane can be manufactured using the process in the related art, which will not be described here. The display units are not manufactured one by one, but a structural plate including a plurality of display units is first manufactured, and then the display unit structural plate is cut to form a plurality of display units.

[0108] Specifically, the light-emitting chip in the embodiment of the present invention can adopt Mini LED chip or Micro LED chip. First, an LED epitaxial layer must be produced, and an N-type doped semiconductor layer, a light-emitting layer and a P-type doped semiconductor layer are sequentially formed on a growth substrate by vapor deposition. Then, the P-type doped half-layer body layer is bonded to the conductive substrate material by metal bonding. The LED epitaxial layer on the conductive substrate is etched into a plurality of LED epitaxial units, and an insulating layer is formed at the edge of the LED epitaxial unit. Finally, a first electrode layer is formed on the substrate, and a second electrode is formed on the N-type doped semiconductor layer of each LED epitaxial unit. The formed structure is cut to obtain a plurality of structures such as Figure 8 The light-emitting chip shown.

[0109] Next, a plurality of pads are formed on the carrier, which is not a carrier of a display unit, but a carrier with a larger area before cutting. The pads on the carrier can be arranged in an array according to the plurality of pads required in the display unit as a pad group, and manufactured according to the above arrangement rules.

[0110] A common electrode is formed at the same position of each pad group, thereby reducing the number of device transfers. The common electrode can be made by evaporation, which is not limited here.

[0111] The light-emitting chips are transferred to the remaining pads in each pad group and soldered. Specifically, the first electrodes of the light-emitting chips are soldered to the pads.

[0112] After transferring each light-emitting chip, each light-emitting chip is packaged, and the packaging layer needs to expose the second electrode of each light-emitting chip and the top of each common electrode.

[0113] Then, a conductive layer is formed on the encapsulation layer to electrically connect the second electrode of each light-emitting chip to each common electrode. Specifically, the conductive layer can be made of a transparent conductive material, such as indium tin oxide (ITO) and other materials, which are not limited here. A protective layer is formed on the conductive layer to insulate and protect the conductive layer, thereby forming a display unit structure board. Both the conductive layer and the protective layer can be made by magnetron sputtering, which is not limited here.

[0114] Finally, the display unit structural plate is cut to form multiple display units, and the single display unit is tested, sorted, etc. Then, the display unit that meets the requirements is transferred to the driving backplane and electrically connected to the driving backplane, thereby obtaining the display device provided by the embodiment of the present invention.

[0115] When packaging the light-emitting chip, it is necessary to first form a first packaging layer and then form a second packaging layer. Fig.11 A third structural schematic diagram of a display unit provided in an embodiment of the present invention; Fig.12 The fourth structural schematic diagram of the display unit provided in the embodiment of the present invention.

[0116] Specifically, if Fig.11 As shown, first, a first encapsulation layer is formed between each light-emitting chip and each common electrode on the carrier; the first encapsulation layer can be made of materials such as epoxy resin, silicone resin, modified resin of epoxy resin or modified resin of silicone resin, wherein dark materials are doped, so that the first encapsulation layer is black. The first encapsulation layer can be made by thermal lamination, inkjet printing, primer coating, etc. The height of the first encapsulation layer needs to be set so that its surface on the side away from the carrier is flush with the surface of the substrate of the light-emitting chip on the side away from the carrier, so that there is a certain distance between the first encapsulation layer and the light-emitting layer, so as to avoid the first encapsulation layer absorbing the emitted light of the light-emitting chip and affecting the brightness of the light-emitting chip.

[0117] Then, if Fig.12 As shown, a second encapsulation layer is formed on the first encapsulation layer; the second encapsulation layer can be made of materials such as epoxy resin, silicone resin, modified resin of epoxy resin or modified resin of silicone resin, wherein light diffusion material is doped, so that the emitted light of the light-emitting chip can be homogenized. The height of the second encapsulation layer needs to be set to expose the top area of ​​the second electrode of each light-emitting chip and each common electrode, so that the conductive layer formed subsequently can contact the top of the second electrode and the common electrode of each light-emitting chip.

[0118] In the display device and manufacturing method provided by the embodiment of the present invention, the display device includes a driving backplane and a plurality of display units located on the driving backplane, and the display unit includes: a carrier; the carrier includes a plurality of pads; at least two light-emitting chips, each light-emitting chip has a different color of emitted light; a light-emitting chip is located on a pad and electrically connected to the pad; a common electrode is located on a pad and electrically connected to the pad; the side of each light-emitting chip facing away from the carrier is connected to the common electrode. The light-emitting chip in the display unit adopts a vertical structure, and the light-emitting area accounts for a higher proportion. Smaller chips can be used under the same brightness requirements, and the chip cost is reduced. There is only one electrode at the bottom of the light-emitting chip and its size is the same as that of the light-emitting chip, thereby reducing a series of risks such as short circuit and metal migration caused by too small an electrode spacing. The light-emitting chip with a vertical structure has a larger thermal conductivity area and lower thermal resistance.

[0119] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0120] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A display device, characterized in that: include: A driving backplane, used for providing a driving signal; and A plurality of display units are located on the driving backplane, and the plurality of display units are electrically connected to the driving backplane respectively; Wherein, the display unit comprises: A carrier board; the carrier board comprises a plurality of pads; at least two light-emitting chips, each of which emits light of different colors; one of the light-emitting chips is located on one of the pads and is electrically connected to the pad; and A common electrode is located on one of the pads and electrically connected to the pad; a side of each of the light-emitting chips facing away from the carrier is connected to the common electrode.

2. The display device according to claim 1, wherein: The light emitting chip comprises: substrate; A first electrode is located between the substrate and the carrier; the first electrode is electrically connected to the corresponding pad on the carrier; a bonding layer, located on a side of the substrate facing away from the first electrode; A first semiconductor layer, located on a side of the bonding layer facing away from the substrate; A light emitting layer, located on a side of the first semiconductor layer away from the bonding layer; A second semiconductor layer is located on a side of the light emitting layer away from the first semiconductor layer; and The second electrode is located on a side of the second semiconductor layer away from the light-emitting layer; the second electrode is electrically connected to the common electrode.

3. The display device according to claim 2, wherein: The orthographic projections of the first semiconductor layer, the light-emitting layer, and the second semiconductor layer in the light-emitting chip on the substrate are located within the orthographic projection of the bonding layer on the substrate, and the orthographic projection of the second electrode on the substrate is located within the orthographic projection of the second semiconductor layer on the substrate; The edges of the bonding layer, the first semiconductor layer, the light emitting layer, the second semiconductor layer and the second electrode are in a step shape; The light emitting chip further comprises: an insulating layer, covering the stepped edges of the bonding layer, the first semiconductor layer, the light emitting layer and the second semiconductor layer and exposing the second electrode; A surface of the second electrode facing away from the substrate is higher than a surface of the insulating layer facing away from the substrate.

4. The display device according to claim 2, wherein: The bonding layer is made of metal material, and the substrate is made of silicon.

5. The display device according to claim 2, wherein: The display unit further comprises: An encapsulation layer filled between each of the light-emitting chips and the common electrode; the encapsulation layer exposes the second electrode of each of the light-emitting chips and a portion of the common electrode; a conductive layer, covering each of the second electrodes and the common electrode exposed by the encapsulation layer; and The protection layer is located on a side of the conductive layer away from the packaging layer.

6. The display device according to claim 5, characterized in that The packaging layer includes a first packaging layer and a second packaging layer; the first packaging layer is located between the second packaging layer and the carrier; The first encapsulation layer is doped with dark material; the second encapsulation layer is doped with light diffusion material.

7. The display device according to claim 6, wherein: A surface of the first packaging layer facing away from the carrier is flush with a surface of the substrate facing away from the carrier.

8. The display device according to any one of claims 1 to 7, characterized in that: The carrier board includes a plurality of through holes corresponding to the plurality of pads one by one; The pads include a first pad and a second pad, the first pad is located on the side of the carrier facing the driving backplane, the second pad is located on the side of the carrier away from the driving backplane, and the first pad and the second pad are electrically connected through the corresponding through holes.

9. A method for manufacturing a display device, characterized in that: include: forming a plurality of pads on a carrier board; forming a plurality of common electrodes on a plurality of pads of the carrier; Transferring a plurality of light-emitting chips to the pads of the carrier and electrically connecting them to the corresponding pads; Encapsulating each of the light-emitting chips so that the encapsulation layer exposes a portion of the second electrode of each of the light-emitting chips and each of the common electrodes; forming a conductive layer on the packaging layer; forming a protective layer on the conductive layer to form a display unit structure plate; Cutting the display unit structural plate to form a plurality of display units; Each of the display units is transferred to a driving backplane and electrically connected to the driving backplane.

10. The manufacturing method according to claim 9, characterized in that: The step of packaging each of the light-emitting chips comprises: A first encapsulation layer is formed between each of the light-emitting chips and each of the common electrodes on the carrier; the first encapsulation layer is doped with a dark material, and a surface of the first encapsulation layer facing away from the carrier is flush with a surface of the substrate of the light-emitting chip facing away from the carrier; A second encapsulation layer is formed on the first encapsulation layer; the second encapsulation layer is doped with a light diffusion material, and the second encapsulation layer exposes a portion of the second electrode of each of the light-emitting chips and each of the common electrodes.

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