Light emitting device, light emitting substrate, and display device

Abstract

The embodiment of the utility model provides a light-emitting device, a light-emitting substrate and a display device, relates to the technical field of display, and is used for improving the production efficiency and the yield. The light-emitting device comprises a plurality of light-emitting units, an adhesive layer and a conductive pattern which are stacked. The light-emitting area of the light-emitting unit located on the lower side is larger than the light-emitting area of the light-emitting unit located on the upper side. The light emitting unit includes a first semiconductor layer, a light emitting layer, and a second semiconductor layer. Every two adjacent light-emitting units are a first light-emitting unit and a second light-emitting unit, and at least part of the edge of the second semiconductor layer of the first light-emitting unit exceeds the first semiconductor layer of the second light-emitting unit. The bonding layer is arranged between two adjacent light-emitting units. The conductive pattern is in electrical contact with an edge portion of the second semiconductor layer of the first light-emitting unit beyond the first semiconductor layer of the second light-emitting unit, and is in electrical contact with an edge portion of the first semiconductor layer of the second light-emitting unit beyond the light-emitting layer. The light-emitting device is used for the light-emitting substrate.

Description

Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a light-emitting device, a light-emitting substrate and a display apparatus. Background Art

[0002] With the development of light emitting diode technology, display devices using sub-millimeter (Mini) or even micron (Micro) light emitting diodes (LED) have been widely used. As a result, not only can the picture contrast of display devices using Micro LED or Mini LED reach the level of organic light emitting diode (OLED) display devices, but also the display devices can retain the technical advantages of liquid crystal display such as low cost, high brightness and high reliability, thereby improving the display effect of the picture and providing users with a better visual experience.

[0003] Among them, the light-emitting device includes a plurality of light-emitting units connected in series, and uses a high voltage to transmit a driving signal to form a high-voltage driven light-emitting device to reduce the driving current and power consumption. However, in the related art, the process of high-voltage driven light-emitting devices is difficult, and the production efficiency and yield are reduced. Utility Model Content

[0004] An object of the embodiments of the present disclosure is to provide a light-emitting device, a light-emitting substrate and a display apparatus, so as to improve production efficiency and yield.

[0005] To achieve the above objectives, the embodiments of the present disclosure provide the following technical solutions:

[0006] On the one hand, a light-emitting device is provided. The light-emitting device includes a plurality of light-emitting units, an adhesive layer, and a conductive pattern stacked in sequence. The light-emitting area of ​​the light-emitting unit located on the lower side is greater than the light-emitting area of ​​the light-emitting unit located on the upper side. The light-emitting unit includes a first semiconductor layer, a light-emitting layer, and a second semiconductor layer stacked in sequence, and at least part of the edge of the first semiconductor layer exceeds the light-emitting layer. Furthermore, two adjacent light-emitting units are respectively a first light-emitting unit and a second light-emitting unit, and at least part of the edge of the second semiconductor layer of the first light-emitting unit exceeds the first semiconductor layer of the second light-emitting unit.

[0007] The adhesive layer is disposed between two adjacent light-emitting units. The conductive pattern is connected to two adjacent light-emitting units. A portion of the conductive pattern is in electrical contact with an edge portion of the second semiconductor layer of the first light-emitting unit that extends beyond the first semiconductor layer of the second light-emitting unit, and another portion of the conductive pattern is in electrical contact with an edge portion of the first semiconductor layer of the second light-emitting unit that extends beyond the light-emitting layer.

[0008] In the above-mentioned light-emitting device, a plurality of light-emitting units stacked in sequence can be bonded and fixed by an adhesive layer by an adhesive process, and electrically connected by a conductive pattern by a deposition and / or patterning process. In this case, the formation of the adhesive layer does not need to consider the conductive performance, and only the bonding process is used to form a reliable connection between the plurality of light-emitting units, and the process difficulty is low. Moreover, the formation of the conductive pattern does not need to consider the reliability of the connection of the plurality of light-emitting units, and only the deposition and / or patterning process is used to form a good conductive connection between the plurality of light-emitting units, and the process difficulty is low. It can be seen from the above that, compared with the related art, the light-emitting device provided in the embodiment of the present disclosure has a low difficulty in the preparation process, and the process is controlled for a single property (connection reliability or conductive performance), and has high controllability, which is conducive to improving production efficiency and yield.

[0009] In some embodiments, the light emitting device further includes a first barrier layer, wherein the first barrier layer covers the conductive pattern and exposed surfaces of one side of the plurality of light emitting units close to the conductive pattern.

[0010] In some embodiments, the light emitting device further comprises a second barrier layer, the second barrier layer being disposed between the conductive pattern and the light emitting unit. The second barrier layer is provided with a first connection hole and a second connection hole. The conductive pattern extends into the first connection hole and the second connection hole, and is in electrical contact with the first semiconductor layer and the second semiconductor layer, respectively.

[0011] In some embodiments, the light emitting device includes a first barrier layer, the first barrier layer includes a first sub-section and a second sub-section. The first sub-section covers the exposed surface of the plurality of light emitting units close to the conductive pattern. The second sub-section covers the conductive pattern. The thickness of the first sub-section is greater than the thickness of the second sub-section.

[0012] In some embodiments, the conductive pattern includes a first overlap portion, a second overlap portion, and a first connection portion. The first overlap portion is disposed on the second semiconductor layer. The second overlap portion is disposed on the first semiconductor layer. The first connection portion is disposed between the first overlap portion and the second overlap portion, and one end of the first connection portion is connected to the first overlap portion, and the other end is connected to the second overlap portion.

[0013] In some embodiments, on a first cross section, the length of the first overlap portion and / or the second overlap portion is greater than or equal to 1 μm. The first cross section is perpendicular to the plane where the first semiconductor layer is located, and perpendicular to the boundary where the first semiconductor layer contacts the second overlap portion. And / or, the distance between the boundary of the first overlap portion and the boundary of the second semiconductor layer of the first light-emitting unit connected thereto is 0 μm to 5 μm. And / or, the distance between the boundary of the second overlap portion and the boundary of the light-emitting layer of the second light-emitting unit connected thereto is 0 μm to 5 μm.

[0014] In some embodiments, on a first cross section, along a first direction, the length of the first connection portion is 2 μm to 4 μm. The first cross section is perpendicular to the plane where the first semiconductor layer is located, and perpendicular to the boundary where the first semiconductor layer contacts the second overlap portion; the first direction is parallel to the plane where the first semiconductor layer is located. And / or, the angle between the first connection portion and the second semiconductor layer is 60° to 80°.

[0015] In some embodiments, current values ​​corresponding to peak values ​​of the luminous efficiency of at least two of the light-emitting units are not equal.

[0016] In some embodiments, the light emitting device includes two light emitting units, and the ratio of the current value corresponding to the peak value of the light emitting efficiency of one of the two light emitting units to the current value corresponding to the peak value of the light emitting efficiency of the other light emitting unit is 5-20.

[0017] In some embodiments, a current value corresponding to a peak value of the luminous efficiency of the light-emitting unit is less than or equal to 0.5 mA.

[0018] In some embodiments, the ratio of the light emitting area of ​​the second light emitting unit to the light emitting area of ​​the first light emitting unit is 10% to 80%.

[0019] In some embodiments, the light emitting device further includes a first electrode, and the first electrode is disposed on an upper surface of the uppermost second semiconductor layer.

[0020] In some embodiments, the light emitting device further includes a second electrode, and the second electrode is disposed on an upper surface of a lowermost portion of the first semiconductor layer that exceeds an edge portion of the light emitting layer.

[0021] In some embodiments, the shape of the orthographic projection of the first semiconductor layer on a reference plane is a rectangle, and the reference plane is a plane where the first semiconductor layer located at the bottom is located. Moreover, in the light-emitting unit located at the bottom, the light-emitting layer exposes a corner area of ​​the first semiconductor layer, and the second electrode is disposed at the corner area.

[0022] In some embodiments, in an orthographic projection onto the reference plane, along the second direction, the second electrode is located on one side of the first semiconductor layer of the second light-emitting unit. Furthermore, the conductive pattern covers a first boundary of the first semiconductor layer of the corresponding second light-emitting unit, the first boundary being perpendicular to the second direction and located between the first electrode and the second electrode.

[0023] In some embodiments, in an orthographic projection onto the reference plane, the second electrode is located on an extension line of a second boundary of the first semiconductor layer of the second light-emitting unit, and the conductive pattern covers the corresponding second boundary of the first semiconductor layer of the second light-emitting unit.

[0024] In some embodiments, the light emitting device further comprises a conductive substrate, a conductive bonding layer, a first electrode and a second electrode. The conductive substrate is disposed on the upper side of the plurality of light emitting units. The conductive bonding layer is disposed between the conductive substrate and the plurality of light emitting units. The first electrode is disposed on a side of the first semiconductor layer farthest from the conductive substrate away from the conductive substrate. The second electrode is disposed on a side of the conductive substrate away from the plurality of light emitting units.

[0025] In another aspect, a light-emitting substrate is provided, wherein the light-emitting substrate comprises a driving backplane and a light-emitting device as described in any one of the above embodiments, wherein the light-emitting device is connected to the driving backplane.

[0026] In another aspect, a display device is provided, wherein the display device comprises the light-emitting substrate as described in the above embodiment.

[0027] The above-mentioned light-emitting substrate and display device have the same structure and beneficial technical effects as the light-emitting devices provided in some of the above-mentioned embodiments, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the present disclosure, the following briefly introduces the drawings required to be used in some embodiments of the present disclosure. Obviously, the drawings described below are only drawings of some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can also be obtained based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams, and are not limitations on the actual size of the product involved in the embodiments of the present disclosure, the actual process of the method, the actual timing of the signal, etc.

[0029] Figure 1 is a structural diagram of a display device according to some embodiments;

[0030] Figure 2 is a structural diagram of another display device according to some embodiments;

[0031] Figure 3 for Figure 1 A sectional view along section line AA;

[0032] Figure 4 for Figure 1 Another cross-sectional view along section line AA;

[0033] Figure 5 is a top view of a light emitting device according to some embodiments;

[0034] Figure 6 for Figure 5 A cross-sectional view along section line BB;

[0035] Figure 7 is a structural diagram of a light emitting device according to some embodiments;

[0036] Figure 8 is a structural diagram of another light emitting device according to some embodiments;

[0037] Fig. 9 is a top view of another light emitting device according to some embodiments;

[0038] Fig.10 is a structural diagram of another light emitting device according to some embodiments;

[0039] Fig.11 is a structural diagram of another light emitting device according to some embodiments;

[0040] Fig.12 is a graph showing the relationship between the luminous efficiency and the current of three light emitting devices according to some embodiments;

[0041] Fig.13 is a graph showing the relationship between the luminous efficiency and the current of two light-emitting units in the same light-emitting device according to some embodiments;

[0042] Fig.14 A comparison diagram of the current magnitude and the peak luminous efficiency of the luminous efficiency of the luminous device at different luminous areas according to some embodiments;

[0043] Fig.15 is a top view of yet another light emitting device according to some embodiments;

[0044] Fig.16 is a top view of yet another light emitting device according to some embodiments;

[0045] Fig.17 is a top view of yet another light emitting device according to some embodiments;

[0046] Fig.18 is a structural diagram of another light emitting device according to some embodiments;

[0047] Fig.19 is a flow chart of a method for preparing a light emitting device according to some embodiments;

[0048] Fig. 20 is a flow chart of a method for preparing a light emitting device according to some embodiments;

[0049] Figure 21 to Figure 24 is a diagram of the preparation steps of a method for preparing a light-emitting device with a vertical structure according to some embodiments;

[0050] Figure 25 to Figure 29 is a diagram showing the steps of manufacturing a method for manufacturing a light-emitting device with a flip-chip structure according to some embodiments;

[0051] Fig.30 is a flow chart of a method for preparing a light emitting device according to some embodiments;

[0052] Fig.31 is a diagram of the preparation steps of a method for preparing a light-emitting device with a vertical structure according to some embodiments;

[0053] Fig.32 is a diagram showing the steps of manufacturing a method for manufacturing a light-emitting device with a flip-chip structure according to some embodiments;

[0054] Fig.33 is a flow chart of a method for preparing a light emitting device according to some embodiments;

[0055] Fig.34 is a diagram of the preparation steps of a method for preparing a light-emitting device with a vertical structure according to some embodiments;

[0056] Fig.35 is a diagram showing the steps of manufacturing a method for manufacturing a light-emitting device with a flip-chip structure according to some embodiments;

[0057] Fig.36 is a diagram of the preparation steps of a method for preparing a light-emitting device with a vertical structure according to some embodiments;

[0058] Fig.37 is a diagram showing the steps of manufacturing a method for manufacturing a light-emitting device with a flip-chip structure according to some embodiments;

[0059] Fig.38 is a diagram of the preparation steps of a method for preparing a light-emitting device with a vertical structure according to some embodiments;

[0060] Fig.39 is a flow chart of a method for preparing a light emitting device according to some embodiments;

[0061] Fig.40is a diagram of the preparation steps of a method for preparing a light-emitting device with a vertical structure according to some embodiments;

[0062] Fig.41 is a diagram of the preparation steps of a method for preparing a light-emitting device with a vertical structure according to some embodiments;

[0063] Fig.42 is a flow chart of a method for preparing a light emitting device according to some embodiments;

[0064] Fig.43 FIG. 1 is a diagram showing the preparation steps of a method for preparing a light-emitting device with a flip-chip structure according to some embodiments. DETAILED DESCRIPTION

[0065] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present disclosure.

[0066] Unless the context requires otherwise, throughout the specification and claims, the term "comprise" and other forms thereof, such as the third person singular form "comprises" and the present participle form "comprising", are to be interpreted as open, inclusive, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific example" or "some examples" and the like are intended to indicate that specific features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present disclosure. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0067] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present disclosure, unless otherwise specified, "plurality" means two or more.

[0068] When describing some embodiments, the expressions "coupled" and "connected" and their derivatives may be used. The term "connected" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. The term "coupled" indicates, for example, that two or more components are in direct physical or electrical contact. The term "coupled" or "communicatively coupled" may also refer to two or more components that are not in direct contact with each other, but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the contents of this document.

[0069] “At least one of A, B, and C” has the same meaning as “at least one of A, B, or C” and both include the following combinations of A, B, and C: A only, B only, C only, the combination of A and B, the combination of A and C, the combination of B and C, and the combination of A, B, and C.

[0070] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0071] The use of "adapted to" or "configured to" herein is meant to be open and inclusive language that does not exclude devices adapted or configured to perform additional tasks or steps.

[0072] Additionally, the use of “based on” is meant to be open and inclusive, as a process, step, calculation, or other action “based on” one or more stated conditions or values ​​may, in practice, be based on additional conditions or values ​​beyond those stated.

[0073] As used herein, "about," "substantially," or "approximately" includes the stated value and an average value that is within an acceptable range of variation from the particular value as determined by one of ordinary skill in the art taking into account the measurements in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

[0074] As used herein, "parallel", "perpendicular", and "equal" include the conditions described and conditions similar to the conditions described, the range of which is within an acceptable range of deviations, wherein the acceptable range of deviations is determined by a person of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, "equal" includes absolute equality and approximate equality, wherein the acceptable range of deviations for approximate equality may include, for example, a difference between the two being equal that is less than or equal to 5% of either.

[0075] It will be understood that when a layer or an element is referred to as being on another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may be present between the layer or element and the other layer or substrate.

[0076] Exemplary embodiments are described herein with reference to cross-sectional views and / or plan views that are idealized exemplary drawings. In the drawings, the thickness of the layers and the area of ​​the regions are exaggerated for clarity. Therefore, variations in the shapes relative to the drawings due to, for example, manufacturing techniques and / or tolerances are conceivable. Therefore, the exemplary embodiments should not be interpreted as being limited to the shapes of the regions shown herein, but include shape deviations due to, for example, manufacturing. For example, an etched region shown as a rectangle will typically have curved features. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shapes of the regions of the device, and are not intended to limit the scope of the exemplary embodiments.

[0077] like Figure 1 and Figure 2 As shown, some embodiments of the present disclosure provide a display device 1000, which may be any device that displays images, whether in motion (eg, video) or fixed (eg, still image), and whether text or images.

[0078] For example, see Figure 1 and Figure 2 The display device 1000 can be a television, a laptop computer, a tablet computer, a car display, a flight display, a portable display product (such as a mobile phone), a wearable device (such as a watch), a camera, a camcorder, a projector, a calculator, a wireless device, a personal digital assistant (PDA), a clock, a global positioning system (GPS) receiver / navigator, a virtual reality (VR) device, an augmented reality (AR) device, an electronic billboard or signboard, or any other product or component with a display function.

[0079] For example, Figure 1 As shown, the display device 1000 may be a portable display product; for example, the display device 1000 may be Figure 1 For another example, see Figure 2 , the display device 1000 may be a wearable device; for example, the display device 1000 may be Figure 2 The watch shown in.

[0080] It should be noted that, according to different application scenarios, the display device 1000 can be a flat display device, a curved display device, a folding display device, etc., and the shape of the display surface of the display device 1000 can be any one of a circular, elliptical, polygonal or irregular shape, but the embodiments of the present disclosure are not limited to this.

[0081] The display device 1000 is used as an example below. Figure 1 Taking the mobile phone shown as an example, some embodiments of the present disclosure are schematically described, but the implementation of the present disclosure is not limited thereto, and any other display device can also be considered as long as the same technical concept is applied.

[0082] In some embodiments, see Figure 3 and Figure 4 The display device 1000 includes a light emitting substrate 100, and the light emitting substrate 100 has a light emitting side and a non-light emitting side opposite to each other. The light emitting side refers to a side of the light emitting substrate 100 that can emit light ( Figure 3 and Figure 4 The non-light-emitting side refers to the other side opposite to the light-emitting side ( Figure 3 and Figure 4 The lower side of the light emitting substrate 100).

[0083] For example, see Figure 3 and Figure 4 The display device 1000 also includes a driving circuit board 200, a housing 300 and a cover plate 400. The cover plate 400 is arranged on the light-emitting side of the light-emitting substrate 100 to protect the light-emitting substrate 100. The driving circuit board 200 is connected to the light-emitting substrate 100 to provide a light-emitting signal to the light-emitting substrate 100.

[0084] The shell 300 may be a box-shaped structure with an opening, the light-emitting substrate 100 and the driving circuit board 200 may be arranged in the shell 300 , and the cover plate 400 is arranged on the light-emitting side of the light-emitting substrate 100 and located at the opening of the shell 300 .

[0085] It should be understood that the above-mentioned display device 1000 can be a liquid crystal display device (Liquid Crystal Display, LCD for short) or a micro light emitting display device (Mini / Micro Light Emitting Display, MLED for short), and the embodiments of the present disclosure do not specifically limit this.

[0086] In some embodiments, Figure 3As shown, the display device 1000 may be a liquid crystal display device. In this case, the light-emitting substrate 100 may be used as a backlight source in the liquid crystal display device to provide backlight for the display panel 500, and the display panel 500 may adjust the light intensity (gray scale) passing through the display panel 500 to realize image display.

[0087] For example, see Figure 3 The display device 1000 further includes a display panel 500, which is disposed on the light-emitting side of the light-emitting substrate 100. The display panel 500 may be, for example, a liquid crystal display panel.

[0088] The light-emitting substrate 100 can directly emit white light, which is then emitted to the display panel 500 after being homogenized. The display panel 500 adjusts the intensity (grayscale) of the light passing through the display panel 500 and realizes full-color display after color conversion.

[0089] Alternatively, the light-emitting substrate 100 may also emit light of other colors (eg, blue), which is then directed to the display panel 500 after color conversion and light homogenization processing. The display panel 500 adjusts the intensity (grayscale) of the light passing through the display panel 500 to achieve full-color display.

[0090] Alternatively, the light emitting substrate 100 can emit light of multiple colors (eg, red, blue, and green), which is then directed toward the display panel 500 after being uniformly treated. The display panel 500 adjusts the intensity (grayscale) of light passing through the display panel 500 to achieve full-color display.

[0091] In other embodiments, see Figure 4 The display device 1000 may be a micro-luminescent display device. In this case, the light-emitting substrate 100 may be used as a display panel of the micro-luminescent display device to directly display.

[0092] The light-emitting substrate 100 can directly emit white light or light of other colors (such as blue) and realize full-color display through color conversion. Alternatively, the light-emitting substrate 100 can directly emit light of multiple colors (such as red, blue and green) to realize full-color display.

[0093] Some embodiments of the present disclosure are exemplarily described below by taking the display device 1000 as a micro-luminescent display device, but the implementation of the present disclosure is not limited thereto, and any other display device may also be considered as long as the same technical concept is applied.

[0094] In some embodiments, see Figure 3 and Figure 4The light-emitting substrate 100 includes a driving backplane 10 and a light-emitting device 20. The light-emitting device 20 is disposed on the driving backplane 10 and connected to the driving backplane 10 to receive a first power signal and a second power signal, thereby driving the light-emitting device 20 to emit light.

[0095] It should be noted that the first power signal and the second power signal are used to provide power voltage to the light emitting device 20. For example, the first power signal is connected to the positive electrode of the power supply, and the second power signal is connected to the negative electrode of the power supply.

[0096] The orthographic projection of the above-mentioned light-emitting device 20 on the driving backplane 10 may be any one of a circle, an ellipse and a polygon, but the embodiments of the present disclosure are not limited thereto. Moreover, the light-emitting device 20 may include Micro LED and / or Mini LED. For example, the radial length of the orthographic projection of the Micro LED on the driving backplane 10 is less than 50 μm, such as 10 μm to 50 μm. For another example, the radial length of the orthographic projection of the MiniLED on the driving backplane 10 is 50 μm to 150 μm, such as 80 μm to 120 μm.

[0097] It should be noted that the radial length of the orthographic projection refers to the length of the connecting line segment between two points on the orthographic projection boundary and passing through the geometric center of the orthographic projection. For example, when the orthographic projection is a quadrilateral, the radial length includes the length of the side and the length of the diagonal. For example, when the orthographic projection is a circle, the radial length is the diameter.

[0098] In some embodiments, see Figure 3 and Figure 4 The light emitting substrate 100 further includes an encapsulation layer 600, and the encapsulation layer 600 covers the light emitting device 20 to protect the light emitting device 20. The material of the encapsulation layer 600 includes transparent silicone.

[0099] In some embodiments, see Figure 5 and Figure 6 , the light emitting device 20 includes a plurality of light emitting units 210 connected in series, and the light emitting unit 210 includes a first semiconductor layer 21, a light emitting layer 22, and a second semiconductor layer 23 which are stacked in sequence, that is, the light emitting layer 22 is arranged between the first semiconductor layer 21 and the second semiconductor layer 23. At this time, the overlapping area of ​​the first semiconductor layer 21, the light emitting layer 22, and the second semiconductor layer 23 is the light emitting area of ​​one light emitting unit 210. In this case, the light emitting device 20 can use a high voltage to transmit a driving signal to form a high voltage driven light emitting device 20, so as to reduce the driving current and reduce the power consumption.

[0100] It should be noted that the shape of the orthographic projection of the light emitting unit 210 on the driving backplane 10 may be any one of a circle, an ellipse and a polygon, but the embodiments of the present disclosure are not limited thereto.

[0101] Among them, one of the first semiconductor layer 21 and the second semiconductor layer 23 is a P-type semiconductor layer, and the other is an N-type semiconductor layer. The light-emitting layer 22 can be, for example, a multiple quantum well layer (Multiple Quantum Well, referred to as MQW). At this time, when a voltage is applied to the light-emitting unit 210, the electrons in the N-type semiconductor layer will migrate to the light-emitting layer 22 and enter the light-emitting layer 22. The holes in the P-type semiconductor layer also migrate to the light-emitting layer 22 and enter the light-emitting layer 22. The electrons entering the light-emitting layer 22 recombine with the holes, thereby generating spontaneous radiation light.

[0102] In the following, some embodiments of the present disclosure are illustrated by taking the first semiconductor layer 21 as an N-type semiconductor layer and the second semiconductor layer 23 as a P-type semiconductor layer as an example, but the implementation mode of the present disclosure is not limited to this, and the first semiconductor layer 21 may be a P-type semiconductor layer and the second semiconductor layer 23 may be an N-type semiconductor layer, as long as the same technical concept is applied.

[0103] In some embodiments, see Figure 4 , Figure 5 and Figure 6 , multiple light-emitting units 210 are stacked in sequence along a direction perpendicular to the driving backplane 10, so that the orthographic projections of the multiple light-emitting units 210 on the driving backplane 10 at least partially overlap, and they can jointly occupy a partial area on the driving backplane 10, thereby compressing the area occupied by the light-emitting device 20 on the driving backplane 10, which is beneficial to improving the arrangement density of the light-emitting device 20 on the driving backplane 10, and further improving the resolution of the display device 1000.

[0104] Here, the shapes of the outer contours of the orthographic projections of the plurality of light-emitting units 210 on the driving backplane 10 may be the same, which is beneficial to the size control between the different light-emitting units 210 and can reduce the difficulty of the process.

[0105] In the related art, multiple light-emitting units are connected by a transparent conductive layer (such as heavily doped N-type gallium nitride) formed by a growth process, or multiple light-emitting units are bonded and connected through a transparent conductive layer (indium tin oxide or indium gallium zinc oxide) by a bonding process, which has low production efficiency and yield. The inventors have found that in the process of forming the transparent conductive layer by the two processes, it is necessary to take into account the reliability of the connection and the conductive performance of the transparent conductive layer. The process is uncontrollable and difficult, resulting in a decrease in production efficiency and yield.

[0106] Based on this, see Figure 5 and Figure 6 Some embodiments of the present disclosure provide a light emitting device 20 , further comprising an adhesive layer 24 and a conductive pattern 25 .

[0107] The material of the adhesive layer 24 may include transparent benzocyclobutene. The material of the conductive pattern 25 may include a metal material, for example, the material of the conductive pattern 25 includes at least one of gold, silver, aluminum, tungsten, nickel, copper and iron.

[0108] The bonding layer 24 is disposed between two adjacent light emitting units 210 to bond and fix the two light emitting units 210 , and the conductive pattern 25 is connected to the two adjacent light emitting units 210 so that a plurality of light emitting units 210 are connected in series.

[0109] For example, see Figure 6 and Fig.10 Among the multiple light-emitting units 210 stacked in sequence, the light-emitting area of ​​the light-emitting unit 210 located on the lower side is larger than the light-emitting area of ​​the light-emitting unit 210 located on the upper side, and at least part of the edge of the first semiconductor layer 21 exceeds the light-emitting layer 22.

[0110] For the convenience of distinguishing and describing, two adjacent light-emitting units 210 are respectively a first light-emitting unit 211 and a second light-emitting unit 212, and the first semiconductor layers 21 of the first light-emitting unit 211 and the second light-emitting unit 212 are respectively marked as 21-1 and 21-2, the light-emitting layers 22 of the first light-emitting unit 211 and the second light-emitting unit 212 are respectively marked as 22-1 and 22-2, and the second semiconductor layers 23 of the first light-emitting unit 211 and the second light-emitting unit 212 are respectively marked as 23-1 and 23-2.

[0111] At this time, at least a portion of the edge of the second semiconductor layer 23 - 1 of the first light emitting unit 211 exceeds the first semiconductor layer 21 - 2 of the second light emitting unit 212 .

[0112] On this basis, if Figure 5 , Figure 6 , Fig. 9 and Fig.10 As shown, a portion of the conductive pattern 25 is electrically in contact with an edge portion of the second semiconductor layer 23-1 of the first light-emitting unit 211 that extends beyond the first semiconductor layer 21-2 of the second light-emitting unit 212, and another portion is electrically in contact with an edge portion of the first semiconductor layer 21-2 of the second light-emitting unit 212 that extends beyond the light-emitting layer 22-2.

[0113] In this case, the multiple light-emitting units 210 stacked in sequence can be bonded and fixed by the bonding layer 24 using a bonding process, and electrically connected by the conductive pattern 25 using a deposition and / or patterning process. In this case, the formation of the bonding layer 24 does not need to consider the conductive performance, and the multiple light-emitting units 210 can be reliably connected only by the bonding process, and the process difficulty is low. In addition, the formation of the conductive pattern 25 does not need to consider the reliability of the connection of the multiple light-emitting units 210, and the multiple light-emitting units 210 can be well conductively connected only by the deposition and / or patterning process, and the process difficulty is low. As can be seen from the above, compared with the related art, the preparation process difficulty of the light-emitting device 20 provided in the embodiment of the present disclosure is low, and the process is controlled for a single property (connection reliability or conductive performance), with high controllability, which is conducive to improving production efficiency and yield.

[0114] In the following, some embodiments of the present disclosure are exemplified by taking the light-emitting device 20 including two stacked light-emitting units 210, and the two stacked light-emitting units 210 are respectively a first light-emitting unit 211 and a second light-emitting unit 212 as an example, but the embodiments of the present disclosure are not limited thereto, and it is also possible to consider including 3, 4 or more light-emitting units 210, as long as the same technical concept is applied.

[0115] In some embodiments, Figure 7 , Figure 8 , Fig.10 and Fig.11 As shown, the light emitting device 20 further includes a first barrier layer 26 , which covers the conductive pattern 25 and the exposed surface of the plurality of light emitting units 210 close to the conductive pattern 25 , so as to play an insulating protection role, thereby improving the service life of the light emitting device 20 .

[0116] It should be noted that the material of the first barrier layer 26 includes an inorganic insulating material. Exemplarily, the material of the first barrier layer 26 includes silicon oxide and / or silicon nitride. For example, the material of the first barrier layer 26 includes silicon dioxide.

[0117] In some embodiments, Figure 7 and Fig.10 As shown, the conductive pattern 25 contacts the side wall of the first semiconductor layer 21 - 2 of the second light emitting unit 212 , that is, there is no other film layer between the conductive pattern 25 and the side wall of the first semiconductor layer 21 - 2 of the second light emitting unit 212 .

[0118] In other embodiments, Figure 8 and Fig.11As shown, the light emitting device 20 further includes a second barrier layer 27, which is disposed between the conductive pattern 25 and the light emitting unit 210. The second barrier layer 27 is provided with a first connection hole 271 and a second connection hole 272, and the conductive pattern 25 extends into the first connection hole 271 and the second connection hole 272, and is electrically in contact with the first semiconductor layer 21-2 of the second light emitting unit 212 and the second semiconductor layer 23-1 of the first light emitting unit 211, respectively.

[0119] It should be noted that the shapes of the first connection hole 271 and the second connection hole 272 may be bar-shaped or frame-shaped, but the embodiments of the present disclosure are not limited thereto.

[0120] In this case, the conductive pattern 25 has no contact with the side wall of the first semiconductor layer 21-2 of the second light-emitting unit 212 and is formed on the second barrier layer 27. Since there are defects in the side wall of the first semiconductor layer 21-2 of the second light-emitting unit 212, the conductive pattern 25 is formed on the second barrier layer 27, and has good adhesion, which is conducive to the formation of the conductive pattern 25, and the conductive pattern 25 and the first semiconductor layer 21-2 of the second light-emitting unit 212 have high conductivity.

[0121] It should be noted that the material of the second barrier layer 27 includes an inorganic insulating material. Exemplarily, the material of the second barrier layer 27 includes silicon oxide and / or silicon nitride. For example, the material of the second barrier layer 27 includes silicon dioxide.

[0122] On this basis, if Figure 8 and Fig.11 As shown, the first barrier layer 26 may include, for example, a first sub-portion 261 and a second sub-portion 262, wherein the first sub-portion 261 covers the exposed surface of the plurality of light-emitting units 210 close to the conductive pattern 25, and the second sub-portion 262 covers the conductive pattern 25. Moreover, the thickness of the first sub-portion 261 is greater than the thickness of the second sub-portion 262.

[0123] Here, if Figure 8 As shown, the first sub-portion 261 may include a first sub-layer 2611 and a second sub-layer 2612, the first sub-layer 2611 covers the exposed surface of the plurality of light-emitting units 210 close to the conductive pattern 25, and the second sub-layer 2612 is disposed on the side of the first sub-layer 2611 away from the light-emitting unit 210. Moreover, the first sub-layer 2611 may be made of the same material as the second barrier layer 27, the first sub-layer 2611 and the second barrier layer 27 are prepared in the same process step, and the second sub-layer 2612 and the second sub-portion 262 are prepared in the same process step, which can simplify the process flow and improve production efficiency.

[0124] The thickness of the first sub-portion 261 may be 2 μm to 4 μm. For example, the thickness of the first sub-portion 261 may be any one of 2 μm, 2.2 μm, 2.4 μm, 2.5 μm, 2.7 μm, 3 μm, 3.3 μm, 3.5 μm, 3.6 μm, 3.8 μm and 4 μm.

[0125] The thickness of the second sub-portion 262 may be 1 μm to 2 μm. For example, the thickness of the second sub-portion 262 may be any one of 1 μm, 1.2 μm, 1.4 μm, 1.5 μm, 1.7 μm, 1.8 μm and 2 μm.

[0126] In some embodiments, see Figure 6 The conductive pattern 25 includes a first overlap portion 251, a second overlap portion 252 and a first connection portion 253. The first overlap portion 251 is arranged on the second semiconductor layer 23-1 of the first light-emitting unit 211, and the second overlap portion 252 is arranged on the first semiconductor layer 21-2 of the second light-emitting unit 212. The first connection portion 253 is arranged between the first overlap portion 251 and the second overlap portion 252, and one end is connected to the first overlap portion 251, and the other end is connected to the second overlap portion 252.

[0127] On this basis, if Figure 6 As shown, on the first cross section, the length D1 of the first overlap portion 251 and / or the second overlap portion 252 is greater than or equal to 1 μm, so that the first overlap portion 251 can form a good conductive contact with the corresponding second semiconductor layer 23-1, and the second overlap portion 252 can form a good conductive contact with the corresponding first semiconductor layer 21-2. The first cross section is perpendicular to the plane where the first semiconductor layer 21-2 is located, and is perpendicular to the boundary where the first semiconductor layer 21-2 and the second overlap portion 252 are in contact.

[0128] Here, in the process of preparing the first overlap portion 251 and the second overlap portion 252, the process accuracy of the etching process and the process accuracy of the bonding process can be comprehensively considered, and the difference between the design value of the overlap length of the first overlap portion 251 and the second overlap portion 252 and the sum of the process accuracy of the etching process and the process accuracy of the bonding process is greater than or equal to 1μm. For example, the process accuracy of the etching process is ±1μm, and the process accuracy of the bonding process is ±2μm. At this time, the design value of the overlap length of the first overlap portion 251 and the second overlap portion 252 can be greater than or equal to 4μm.

[0129] The distance D2 between the boundary of the first overlap portion 251 and the boundary of the second semiconductor layer 23 of the connected first light emitting unit 211 is 0 μm to 5 μm to avoid the problem of short circuit caused by the first overlap portion 251 connecting to the first semiconductor layer 21 under the corresponding second semiconductor layer 23 .

[0130] The distance D3 between the boundary of the second overlap portion 252 and the boundary of the light emitting layer 22 of the connected second light emitting unit 212 is 0 μm to 5 μm to avoid the problem of short circuit caused by the second overlap portion 252 connecting to the second semiconductor layer 23 on the upper side of the corresponding first semiconductor layer 21 .

[0131] In some embodiments, see Figure 6 , the angle between the first connection portion 253 and the second semiconductor layer 23-1 of the first light emitting unit 211 is 60° to 80°. Exemplarily, the angle between the first connection portion 253 and the second semiconductor layer 23-1 of the first light emitting unit 211 is any one of 60°, 62°, 65°, 67°, 70°, 73°, 75°, 78° and 80°, but the embodiments of the present disclosure are not limited thereto.

[0132] On this basis, if Figure 6 As shown, on the first cross section, along the first direction X, the length D4 of the first connection portion 253 may be 2 μm to 4 μm, and the first direction X is parallel to the plane where the first semiconductor layer 21-2 is located. For example, the length D4 of the first connection portion 253 may be any one of 2 μm, 2.2 μm, 2.4 μm, 2.5 μm, 2.7 μm, 3 μm, 3.3 μm, 3.5 μm, 3.6 μm, 3.8 μm and 4 μm.

[0133] Fig.12 is a graph showing the relationship between the luminous efficiency and the current of three light-emitting devices according to some embodiments. Fig.12 In the embodiment, the light emitting device A, the light emitting device B and the light emitting device C are optimized in different current ranges. The light emitting units 210 of the same light emitting device 20 are of the same type, and the light emitting units 210 of different light emitting devices 20 are of different types, that is, the light emitting devices A, the light emitting devices B and the light emitting devices C include light emitting units 210 of different types.

[0134] It should be noted that the same type means that the current values ​​corresponding to the peak values ​​of the luminous efficiency of the light-emitting unit 210 are substantially equal, while the opposite is true for different types.

[0135] Depend on Fig.12 It can be seen that the current values ​​corresponding to the peak values ​​of the luminous efficiency of the light-emitting device A, the light-emitting device B and the light-emitting device C are very different. Using any one of the light-emitting devices 20 cannot make the luminous efficiency of the light-emitting device 20 higher in the entire grayscale.

[0136] Fig.13 is a graph showing the relationship between the luminous efficiency and the current of two light-emitting units in the same light-emitting device according to some embodiments. Fig.13In the embodiment, the luminous efficiency of the light emitting unit D and the light emitting unit E in the same light emitting device 20 in the working current range under the whole gray scale is optimized. The light emitting unit D and the light emitting unit E are of different types.

[0137] Depend on Fig.13 It can be seen that the current values ​​corresponding to the peak values ​​of the luminous efficiency of the light-emitting unit D and the light-emitting unit E are different. The luminous efficiencies of the light-emitting unit D and the light-emitting unit E compensate each other, so that the luminous efficiency of the light-emitting device 20 is higher in a larger current range and the change of the luminous efficiency is relatively gentle.

[0138] Based on this, see Fig.11 and Fig.13 In the light-emitting device 20 provided by some embodiments of the present disclosure, the current values ​​corresponding to the peak values ​​of the luminous efficiency of at least two light-emitting units 210 in the light-emitting device 20 are not equal. In this way, the two light-emitting units 210 with unequal current values ​​corresponding to the peak values ​​of the luminous efficiency can be compensated by differentiation, so that the luminous efficiency of the light-emitting device 20 in the whole gray scale is higher, and the change of the luminous efficiency in the whole gray scale is relatively gentle.

[0139] For example, for two light-emitting units 210 with unequal current values ​​corresponding to the peak values ​​of the luminous efficiency, at low grayscale, one has lower luminous efficiency and the other has higher luminous efficiency; at high grayscale, one has lower luminous efficiency and the other has higher luminous efficiency, so that the luminous efficiency of the light-emitting device 20 is relatively stable under the entire grayscale, thereby reducing the difficulty of algorithm correction.

[0140] In addition, the current value corresponding to the peak value of the luminous efficiency of the above-mentioned light-emitting unit 210 is less than or equal to 0.5 mA, so as to avoid the luminous efficiency of the light-emitting device 20 being very low when the current is small.

[0141] In some embodiments, Figure 6 and Fig.13 As shown, the light emitting device 20 includes two light emitting units 210. Among the two light emitting units 210, the current value at the intersection of the luminous efficiency and current curve of one and the luminous efficiency and current curve of the other is the first target current value.

[0142] Moreover, in the entire grayscale, the minimum current value of the light emitting device 20 is the first preset current value, the maximum current value of the light emitting device 20 is the second preset current value, and the difference between the second preset current value and the first preset current value is the first difference. The difference between the first target current value and the first preset current value is the second difference, and the ratio of the second difference to the first difference is 1 / 2 to 2 / 3, so that the compensation effect of the two light emitting units 210 in the entire grayscale is more uniform, and the change of the luminous efficiency is more gentle.

[0143] In some embodiments, Figure 6and Fig.13 As shown, the light emitting device 20 includes two light emitting units 210. Among the two light emitting units 210, the current value corresponding to the peak value of the luminous efficiency of one and the current value corresponding to the peak value of the luminous efficiency of the other are 5 to 20. For example, the current value corresponding to the peak value of the luminous efficiency of one is 0.03mA, and the current value corresponding to the peak value of the luminous efficiency of the other is 0.3mA. In this case, by compensating the luminous efficiency of different light emitting units 210, the luminous efficiency of the light emitting device 20 in the entire grayscale can be higher and the change is relatively gentle.

[0144] It should be understood that the current value corresponding to the peak value of the luminous efficiency of the light-emitting unit 210 can be adjusted according to the doping concentration of the first semiconductor layer 21, the doping concentration of the second semiconductor layer 23 and the thickness of the light-emitting layer 22, and can also be adjusted according to the light-emitting area of ​​the light-emitting unit 210, but the embodiments of the present disclosure are not limited to this.

[0145] Fig.14 FIG. 4 is a comparison diagram of the current magnitude and the peak luminous efficiency of the luminous device at different luminous areas according to some embodiments. Fig.14 It can be seen that the current at the peak of the luminous efficiency is roughly linearly related to the luminous area. 2 (e.g. 40μm*40μm) down to 225μm 2 In this way, the light emitting area of ​​the plurality of light emitting units 210 in the light emitting device 20 can be set based on the linear relationship between the current at the peak light emitting efficiency and the light emitting area and the required brightness.

[0146] In addition, based on Fig.14 It can be seen that the current value corresponding to the peak value of the luminous efficiency of the light-emitting unit 210 can be shifted to the left (reduced) by reducing the light-emitting area of ​​the light-emitting unit 210. For example, when the light-emitting device 20 includes two light-emitting units 210, the area of ​​the upper light-emitting unit 210 can be reduced to reduce the current value corresponding to the peak value of the luminous efficiency of the light-emitting unit 210.

[0147] It should be noted that, based on the relationship between the peak luminous efficiency and the luminous area, when the decrease in the peak luminous efficiency is less than or equal to 10%, the current value corresponding to the peak luminous efficiency of the light-emitting unit 210 can be adjusted by reducing the light-emitting area of ​​the light-emitting unit 210, so that the current value corresponding to the peak luminous efficiency can be adjusted when the luminous efficiency decreases slightly.

[0148] In some embodiments, Figure 5 and Fig. 9As shown, the ratio of the light emitting area of ​​the second light emitting unit 212 to the light emitting area of ​​the first light emitting unit 211 is 10% to 80%. Exemplarily, the ratio of the light emitting area of ​​the second light emitting unit 212 to the light emitting area of ​​the first light emitting unit 211 is 10%, 20%, 40%, 50%, 60%, 70% and 80%, which can be adjusted by adjusting the overlap of the conductive pattern 40 and the overlap area, but the embodiments of the present disclosure are not limited thereto.

[0149] In some embodiments, see Figure 7 and Figure 8 The light emitting device 20 further includes a first electrode 281, which is disposed on the upper surface of the uppermost second semiconductor layer 23. The first electrode 281 may be bonded to the driving backplane 10, for example, to receive a first power signal.

[0150] It should be noted that the material of the first electrode 281 includes a transparent metal oxide. Transparent metal oxide refers to a metal oxide with a light transmittance greater than or equal to 90%. Exemplarily, the material of the first electrode 281 includes at least one of indium tin oxide, indium tin zinc oxide, indium gallium zinc oxide, indium tin zinc oxide, and indium gallium tin oxide.

[0151] At this time, the light-emitting device 20 can be a vertically mounted structure. Moreover, the light-emitting device 20 can be a Micro LED, and the radial length of the positive projection of the light-emitting device 20 on the driving backplane 10 can be 30μm to 40μm. On this basis, after a plurality of light-emitting devices 20 are transferred to the driving backplane 10 in large quantities, the first semiconductor layer 21 of the plurality of light-emitting devices 20, which is farthest from the first electrode 281, can be connected to the driving backplane 10 through the second electrode layer and the wiring to receive the second power signal. At the same time, in the light-emitting device 20 with a vertically mounted structure, the light-emitting unit 210 located at the bottom does not need to prepare the second electrode, so the light-emitting area of ​​the light-emitting unit 210 adjacent to the upper side can be 80% of the light-emitting area of ​​the light-emitting unit 210 at the bottom.

[0152] In other embodiments, see Fig.10 and Fig.11 The light emitting device 20 further includes a first electrode 281 and a second electrode 282. The first electrode 281 is disposed on the upper surface of the second semiconductor layer 23 at the uppermost side. The first electrode 281 can be bonded to the driving backplane 10, for example, to receive the first power signal. The second electrode 282 is disposed on the upper surface of the edge portion of the first semiconductor layer 21 at the lowermost side that exceeds the light emitting layer 22. The second electrode 282 can also be bonded to the driving backplane 10, for example, to receive the second power signal.

[0153] Here, the second electrode 282 may be a single-layer structure or a multi-layer structure. For example, the second electrode 282 includes a first sub-electrode 2821 and a second sub-electrode 2822 that are stacked, and the second sub-electrode 2822 is located on the upper side of the first sub-electrode 2821. The first sub-electrode 2821 is used to reduce contact resistance, and the second sub-electrode 2822 is used to improve welding yield. Fig.10 and Fig.11 In the figure, the second electrode 282 includes a first sub-electrode 2821 and a second sub-electrode 2822 as an example for illustration, but the embodiments of the present disclosure are not limited thereto.

[0154] It should be noted that the materials of the first electrode 281 and the second electrode 282 include transparent metal oxides. Transparent metal oxides refer to metal oxides with a light transmittance greater than or equal to 90%. Exemplarily, the materials of the first electrode 281 and the second electrode 282 include at least one of indium tin oxide, indium tin zinc oxide, indium gallium zinc oxide, indium tin zinc oxide, and indium gallium tin oxide.

[0155] At this time, the light emitting device 20 is a flip-chip structure. Moreover, the light emitting device 20 may be a Micro LED or a Mini LED. For example, the light emitting device 20 may be a Micro LED, and the radial length of the orthographic projection of the light emitting device 20 on the driving backplane 10 may be 30 μm to 50 μm.

[0156] It should be noted that, when the light emitting device 20 is a flip-chip structure, the light emitting device 20 may further include a first substrate 110 , and a plurality of light emitting units 210 are sequentially stacked on the first substrate 110 .

[0157] For some examples, see Fig. 9 , Fig.15 , Fig.16 and Fig.17 The shape of the orthographic projection of the first semiconductor layer 21 on the reference plane is a rectangle, and the reference plane is the plane where the first semiconductor layer 21 located at the bottom is located.

[0158] On this basis, in the light-emitting unit 210 located at the lowermost side, the light-emitting layer 22 exposes a corner area S of the first semiconductor layer 21, and the second electrode 282 is arranged in the corner area S, which is beneficial to reduce the avoidance area of ​​the light-emitting layer 22 and increase the area of ​​the light-emitting layer 22, thereby increasing the light-emitting area and improving the light-emitting efficiency.

[0159] It should be noted that the boundary of the corner area S may be, for example, arc-shaped, so as to further reduce the avoidance area of ​​the light-emitting layer 22 and increase the area of ​​the light-emitting layer 22 , thereby increasing the light-emitting area and improving the light-emitting efficiency.

[0160] In some examples, such as Fig.15As shown, in the orthographic projection onto the reference plane, along the second direction Y, the second electrode 282 is located on one side of the first semiconductor layer 21-2 of the second light-emitting unit 212. Moreover, the conductive pattern 25 covers the first boundary L1 of the first semiconductor layer 21-2 of the corresponding second light-emitting unit 212, and the first boundary L1 is perpendicular to the second direction Y and is located between the first electrode 281 and the second electrode 282. At this time, most of the current flows from the first boundary L1 to the second electrode 282, and the effective light-emitting area can be considered to be Fig.15 In the M region shown in FIG, the effective luminous area is 1 / 4 of the luminous area.

[0161] In some examples, such as Fig.16 As shown, in the orthographic projection onto the reference plane, the second electrode 282 is located on the extension line of the second boundary L2 of the first semiconductor layer 21-2 of the second light-emitting unit 212. Moreover, the conductive pattern 25 covers the second boundary L2 of the first semiconductor layer 21-2 of the corresponding second light-emitting unit 212. At this time, most of the current flows from the second boundary L2 to the second electrode 282, and the effective light-emitting area can be considered as Fig.16 In the N region shown in the figure, the effective light-emitting area is 1 / 4 of the light-emitting area.

[0162] It should be noted that the first boundary L1 and the second boundary L2 may be two intersecting boundaries of the first semiconductor layer 21 - 2 of the second light emitting unit 212 that are close to the corner area S.

[0163] In some examples, such as Fig.17 As shown, in the orthographic projection onto the reference plane, along the second direction Y, the second electrode 282 is located on one side of the first semiconductor layer 21 - 2 of the second light emitting unit 212 . Also, the second electrode 282 is located on the extension line of the second boundary L2 of the first semiconductor layer 21 - 2 of the second light emitting unit 212 .

[0164] On this basis, the conductive pattern 25 covers the first boundary L1 and the second boundary L2 of the first semiconductor layer 21-2 of the corresponding second light-emitting unit 212. At this time, part of the current flows from the first boundary L1 to the second electrode 282, and part of the current flows from the second boundary L2 to the second electrode 282. The effective light-emitting area can be considered as Fig.17 In the T region shown in , the effective luminous area is 1 / 2 of the luminous area.

[0165] It should be understood that when the conductive pattern 25 covers all the boundaries around the first semiconductor layer 21-2 of the corresponding second light-emitting unit 212, since the first boundary L1 and the second boundary L2 are close to the second electrode 282, most of the current will still flow from the first boundary L1 and the second boundary L2 to the second electrode 282. Therefore, the conductive pattern 25 only covers the first boundary L1 and / or the second boundary L2, and the manufacturing cost can be reduced without significantly reducing the effective light-emitting area.

[0166] Based on the above, the effective light emitting area can also be adjusted by covering the boundary of the first semiconductor layer 21 - 2 of the second light emitting unit 212 with the conductive pattern 25 , thereby adjusting the current value corresponding to the peak value of the light emitting efficiency.

[0167] In addition, when the light-emitting device 20 includes 3, 4 or more light-emitting units 210, the conductive pattern 25 can only cover the first boundary L1 and / or the second boundary L2 to reduce the shading area of ​​the conductive pattern 25 and improve the light extraction efficiency without significantly reducing the effective light-emitting area.

[0168] In some other embodiments, Fig.18 As shown, the light emitting device 20 further includes a first electrode 281 , a second electrode 282 , a conductive substrate 291 and a conductive bonding layer 292 .

[0169] like Fig.18 As shown, the conductive substrate 291 is disposed on the upper side of the plurality of light emitting units 210 ( Fig.18 The conductive bonding layer 292 may be disposed between the conductive substrate 291 and the plurality of light emitting units 210 to bond the conductive substrate 291 to the plurality of light emitting units 210 .

[0170] Furthermore, the first electrode 281 is disposed on a side of the first semiconductor layer 21 farthest from the conductive substrate 291 and away from the conductive substrate 291; the first electrode 281 can be bonded to the driving backplane 10, for example, to receive the first power signal. The second electrode 282 is disposed on a side of the conductive substrate 291 farthest from the plurality of light-emitting units 210, and the second electrode 282 can, for example, cover the entire conductive substrate 291; the second electrode 282 can, for example, be connected to the driving backplane 10 through a wire to receive the second power signal.

[0171] At this time, the light emitting device 20 may be a vertical structure. Moreover, the light emitting device 20 may be a Mini LED, and the radial length of the orthographic projection of the light emitting device 20 on the driving backplane 10 may be greater than or equal to 50 μm. On this basis, multiple light emitting devices 20 may be transferred to the driving backplane 10 individually for die bonding.

[0172] It should be understood that when the light emitting device 20 emits red light, the first substrate 110 (see below for details) used in the process of forming the light emitting device 20 by the growth process may be a gallium arsenide substrate, and the first substrate 110 is opaque. In the flip-chip structure light emitting device 20, the light emitting device 20 needs to be transferred again, resulting in yield loss. Based on this, the light emitting device 20 with a red light emitting color may be a vertical structure to improve the production yield.

[0173] Some embodiments of the present disclosure also provide a method for preparing a light emitting device 20, see Fig.19 , the preparation method includes S100~S200.

[0174] S100 : forming a plurality of light emitting units 210 and an adhesive layer 24 .

[0175] In the above steps, a plurality of light emitting units 210 are stacked in sequence, and the adhesive layer 24 is disposed between two adjacent light emitting units 210 to bond and fix the two light emitting units 210 .

[0176] The light emitting area of ​​the light emitting unit 210 located at the lower side is greater than the light emitting area of ​​the light emitting unit 210 located at the upper side. The light emitting unit 210 includes a first semiconductor layer 21, a light emitting layer 22, and a second semiconductor layer 23 which are stacked in sequence, and at least part of the edge of the first semiconductor layer 21 exceeds the light emitting layer 22. Moreover, two adjacent light emitting units 210 are respectively a first light emitting unit 211 and a second light emitting unit 212, and at least part of the edge of the second semiconductor layer 23-1 of the first light emitting unit 211 exceeds the first semiconductor layer 21-2 of the second light emitting unit 212.

[0177] In some embodiments, Fig. 20 As shown, S100 includes S110 to S140.

[0178] Figure 21 to Figure 24 is a diagram of the preparation steps of a method for preparing a light-emitting device with a vertical structure according to some embodiments; Figure 25 to Figure 29 FIG. 1 is a diagram showing the preparation steps of a method for preparing a light-emitting device with a flip-chip structure according to some embodiments.

[0179] S110: Fig.21 and Fig.25 As shown, a first light emitting unit 211 is formed on the first substrate 110 .

[0180] In the above steps, the first semiconductor film 21', the light-emitting film 22' and the second semiconductor film 23' can be sequentially formed on the first substrate 110 through a growth process; then, the first semiconductor film 21', the light-emitting film 22' and the second semiconductor film 23' can be divided into a plurality of first light-emitting units 211 arranged at intervals through an etching process, and the light-emitting layer 22 and the second semiconductor layer 23 are retracted relative to the first semiconductor layer 21 to form a step. It should be noted that the first substrate 110 can be any one of a sapphire substrate, a silicon substrate and a gallium arsenide substrate, and the embodiments of the present disclosure are not limited thereto.

[0181] S120: Fig. 22 and Fig.26 As shown, the second light emitting unit 212 is formed on the second substrate 120 .

[0182] In the above steps, the first semiconductor film 21', the light-emitting film 22' and the second semiconductor film 23' can be sequentially formed on the second substrate 120 through a growth process; then, the first semiconductor film 21', the light-emitting film 22' and the second semiconductor film 23' can be divided into a plurality of second light-emitting units 212 arranged at intervals through an etching process, and the light-emitting layer 22 and the second semiconductor layer 23 are retracted relative to the first semiconductor layer 21 to form a step. The light-emitting area of ​​the second light-emitting unit 212 is smaller than the light-emitting area of ​​the first light-emitting unit 211.

[0183] It should be noted that the second substrate 120 can be any one of a sapphire substrate, a silicon substrate and a gallium arsenide substrate, and the embodiments of the present disclosure are not limited thereto. In addition, the order of S110 and S120 is not fixed, and S110 can be performed first and then S120; or S120 can be performed first and then S110; or S110 and S120 can be performed simultaneously.

[0184] S130: Fig.23 and Fig. 27 As shown, the third substrate 130 is connected to the side of the second light emitting unit 212 away from the second substrate 120 by means of a temporary bonding adhesive 30, and the second substrate 120 is removed.

[0185] In the above steps, the second substrate 120 can be removed by any one of mechanical grinding, mechanical stripping and etching processes. In addition, the material of the temporary bonding glue 30 includes resin and / or polydimethylsiloxane, so that the third substrate 130 and the second light-emitting unit 212 can be separated in a subsequent process. It should be noted that the third substrate 130 can be any one of a sapphire substrate, a silicon substrate, a glass substrate and a gallium arsenide substrate, and the embodiments of the present disclosure are not limited thereto.

[0186] S140: Fig.24 and Fig.28As shown, the side of the second light emitting unit 212 away from the third substrate 130 is connected to the side of the first light emitting unit 211 away from the first substrate 110 through the adhesive layer 24, and the third substrate 130 is removed.

[0187] In the above steps, the adhesive layer 24 can be formed on the side of the second light-emitting unit 212 away from the third substrate 130, or the side of the first light-emitting unit 211 away from the first substrate 110, by coating or printing. In addition, the third substrate 130 can be removed by any one of mechanical grinding, mechanical stripping and etching processes. For example, the third substrate 130 can be dissociated by laser, so that the temporary bonding glue 30 and the third substrate 130 are removed.

[0188] In the case where the light emitting device 20 is a flip-chip structure, between S110 and S130, refer to Fig.29 and Fig.30 , S100 also includes S150.

[0189] S150: Fig.29 As shown, a first sub-electrode 2821 is formed.

[0190] In the above steps, the first sub-electrode 2821 is disposed on the upper surface of the edge portion of the first semiconductor layer 21 that exceeds the light-emitting layer 22, that is, the first sub-electrode 2821 is disposed on a step to reduce contact resistance. The first sub-electrode 2821 can be formed using a mask plate and an evaporation process, but the embodiments of the present disclosure are not limited thereto.

[0191] In this case, after preparing the first light-emitting unit 211, the first sub-electrode 2821 directly contacts the first semiconductor layer 21, which can avoid over-etching or incomplete removal of other subsequent film layers (such as the second blocking layer 282), resulting in poor conductive connection between the first sub-electrode 2821 and the first semiconductor layer 21.

[0192] S200: Fig.31 and Fig.32 As shown, a conductive pattern 25 is formed.

[0193] In the above steps, the conductive pattern 25 is connected to two adjacent light-emitting units 210. A portion of the conductive pattern 25 is electrically in contact with the edge portion of the second semiconductor layer 23-1 of the first light-emitting unit 211 that exceeds the first semiconductor layer 21-2 of the second light-emitting unit 212, and another portion is electrically in contact with the edge portion of the first semiconductor layer 21-2 of the second light-emitting unit 212 that exceeds the light-emitting layer 22-2. The conductive pattern 25 can be formed by using a mask plate and an evaporation process, but the embodiments of the present disclosure are not limited thereto.

[0194] In some embodiments, Fig.33 As shown, S300 is included before S200.

[0195] S300: Fig.34 and Fig.35 As shown, a second barrier film 27' is formed.

[0196] In the above steps, the second barrier film 27 ′ covers the first light emitting unit 211, the second light emitting unit 212 and the adhesive layer 24. In addition, the second barrier film 27 ′ is provided with a first connection hole 271 and a second connection hole 272, wherein the first connection hole 271 exposes the first semiconductor layer 21 - 2 of the second light emitting unit 212, and the second connection hole 272 exposes the second semiconductor layer 23 - 1 of the first light emitting unit 211.

[0197] On this basis, combined with Fig.11 The conductive pattern 25 extends into the first connection hole 271 and the second connection hole 272, and is electrically connected to the first semiconductor layer 21-2 and the second semiconductor layer 23-1, respectively. Moreover, the second barrier layer 27 is a second barrier film 27'.

[0198] The portion located between the conductive pattern 25 and the light emitting unit 210 .

[0199] In some embodiments, Fig.33 As shown, after S200, the preparation method further includes S400.

[0200] S400: Fig.36 and Fig.37 As shown, a first barrier film 26' is formed.

[0201] In the above steps, the first barrier film 26 ′ covers the conductive pattern 25 and the exposed surface of the first light emitting unit 211 and the second light emitting unit 212 close to the conductive pattern 25. At this time, the first barrier layer 26 is the first barrier film 26 ′.

[0202] and the second barrier film 27 ′ is located outside the conductive pattern 25 .

[0203] After forming the first barrier film 26', the first barrier film 26' may further include a first via hole ( Fig.36 and Fig.37 The first via hole exposes the second semiconductor layer 23-2 of the second light emitting unit 212, so as to form the first electrode 281 in the subsequent process. In addition, when the light emitting device 20 is a flip-chip structure, the first barrier film 26' can also be provided with a second via hole ( Fig.37 The second via hole exposes the first sub-electrode 2821 to facilitate the subsequent process to form the second sub-electrode 2822 (see Fig.43 ).

[0204] When the light emitting device 20 is a vertically mounted structure, and the light emitting device 20 can be transferred to the driving backplane 10 by mass transfer, the driving backplane 10 is connected through the second electrode layer and the wiring to receive the second power signal, for example, when the light emitting device 20 is a Micro LED, Fig.33 As shown, after S400, the preparation method further includes S500.

[0205] S500: Fig.38 As shown, a first electrode 281 is formed.

[0206] In the above steps, the first electrode 281 extends into the first via hole and electrically contacts the second semiconductor layer 23-2 to provide a first power signal. The first electrode 281 can be formed by using a mask plate and an evaporation process, but the embodiments of the present disclosure are not limited thereto.

[0207] It should be understood that during the process of S200 to S500 , the first substrate 110 may still be used to provide support, and after S500 , the first substrate 110 may be removed to form the light emitting device 20 .

[0208] In the case where the light emitting device 20 is a vertically mounted structure and the light emitting device 20 can be transferred to the driving backplane 10 for die bonding, for example, the light emitting device 20 is a Mini LED, after 400, Fig.39 As shown, the above preparation method also includes S610 to S620.

[0209] S610: Fig.40 As shown, the conductive substrate 291 is connected to the side of the second light emitting unit 212 away from the first substrate 110 through the conductive bonding layer 292, and the first substrate 110 is removed.

[0210] In the above steps, the first substrate 110 can be removed by any one of mechanical grinding, mechanical stripping and etching processes. In addition, the conductive bonding layer 292 includes a conductive glue, and the conductive substrate 291 can be a silicon substrate.

[0211] S620: Fig.41 As shown, a first electrode 281 and a second electrode 282 are formed.

[0212] In the above steps, the first electrode 281 is disposed on a side of the first semiconductor layer 21 farthest from the conductive substrate 291 and away from the conductive substrate 291, and the second electrode 282 is disposed on a side of the conductive substrate 291 and away from the plurality of light-emitting units 210. The first electrode 281 and the second electrode 282 may be formed using a mask plate and an evaporation process, but the embodiments of the present disclosure are not limited thereto.

[0213] It should be noted that in S610, multiple second light-emitting units 212 can be connected to a conductive substrate 291 through a conductive bonding layer 292. At this time, after S620, it is necessary to cut the conductive substrate 291 and the conductive bonding layer 292 to form multiple independent light-emitting devices 20.

[0214] In the case where the light emitting device 20 is a flip-chip structure, such as Fig.42 As shown, after S400, the preparation method further includes S700.

[0215] S700: Fig.43 As shown, a first electrode 281 and a second sub-electrode 2822 are formed.

[0216] In the above steps, the first electrode 281 extends into the first via hole and electrically contacts the second semiconductor layer 23-2 to provide a first power signal. The second sub-electrode 2822 is located on a side of the first sub-electrode 2821 away from the first semiconductor layer 21-1 of the first light-emitting unit 211, and is electrically in contact with the first sub-electrode 2821. At this time, the first sub-electrode 2821 and the second sub-electrode 2822 form the second electrode 282. The first electrode 281 and the second sub-electrode 2822 can be formed by using a mask plate and an evaporation process, but the embodiments of the present disclosure are not limited thereto.

[0217] It should be understood that during the processes of S200 to S400 and S700 , the first substrate 110 may still be used to provide support, and after S700 , the first substrate 110 may be removed to form the light emitting device 20 .

[0218] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0219] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be thought of by any person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A light emitting device, characterized in that: include: A plurality of light-emitting units stacked in sequence, wherein the light-emitting area of ​​the light-emitting unit located at the lower side is greater than the light-emitting area of ​​the light-emitting unit located at the upper side; the light-emitting unit comprises a first semiconductor layer, a light-emitting layer, and a second semiconductor layer stacked in sequence, wherein at least a portion of the edge of the first semiconductor layer exceeds the light-emitting layer; and two adjacent light-emitting units are respectively a first light-emitting unit and a second light-emitting unit, wherein at least a portion of the edge of the second semiconductor layer of the first light-emitting unit exceeds the first semiconductor layer of the second light-emitting unit; An adhesive layer is disposed between two adjacent light-emitting units; A conductive pattern is connected to two adjacent light-emitting units; a portion of the conductive pattern is electrically in contact with an edge portion of the second semiconductor layer of the first light-emitting unit that extends beyond the first semiconductor layer of the second light-emitting unit, and another portion of the conductive pattern is electrically in contact with an edge portion of the first semiconductor layer of the second light-emitting unit that extends beyond the light-emitting layer.

2. The light emitting device according to claim 1, characterized in that: Also includes: The first barrier layer covers the conductive pattern and the exposed surfaces of the plurality of light emitting units close to the conductive pattern.

3. The light emitting device according to claim 1, characterized in that: Also includes: The second barrier layer is arranged between the conductive pattern and the light emitting unit; the second barrier layer is provided with a first connection hole and a second connection hole; the conductive pattern extends into the first connection hole and the second connection hole, and is in electrical contact with the first semiconductor layer and the second semiconductor layer respectively.

4. The light emitting device according to claim 3, characterized in that: comprising a first barrier layer, the first barrier layer comprising: A first sub-portion, covering the exposed surface of the plurality of light-emitting units close to the conductive pattern; The second sub-portion covers the conductive pattern; the thickness of the first sub-portion is greater than the thickness of the second sub-portion.

5. The light emitting device according to claim 1, characterized in that: The conductive pattern comprises: A first overlapping portion is disposed on the second semiconductor layer; A second overlapping portion is disposed on the first semiconductor layer; The first connecting portion is disposed between the first overlapping portion and the second overlapping portion, and one end of the first connecting portion is connected to the first overlapping portion, and the other end of the first connecting portion is connected to the second overlapping portion.

6. The light emitting device according to claim 5, characterized in that: On a first cross section, the length of the first overlapping portion and / or the second overlapping portion is greater than or equal to 1 μm; the first cross section is perpendicular to the plane where the first semiconductor layer is located, and perpendicular to the boundary where the first semiconductor layer contacts the second overlapping portion; and / or, The distance between the boundary of the first overlapping portion and the boundary of the second semiconductor layer of the first light-emitting unit connected thereto is 0 μm to 5 μm; and / or, A distance between a boundary of the second overlapping portion and a boundary of the light-emitting layer of the connected second light-emitting unit is 0 μm to 5 μm.

7. The light emitting device according to claim 5, characterized in that: On the first cross section, along the first direction, the length of the first connecting portion is 2μm to 4μm; the first cross section is perpendicular to the plane where the first semiconductor layer is located, and is perpendicular to the boundary where the first semiconductor layer contacts the second overlapping portion; the first direction is parallel to the plane where the first semiconductor layer is located; and / or the angle between the first connecting portion and the second semiconductor layer is 60° to 80°.

8. The light emitting device according to claim 1, characterized in that: The current values ​​corresponding to the peak values ​​of the luminous efficiency of at least two of the light-emitting units are not equal.

9. The light emitting device according to claim 8, characterized in that: The invention comprises two light-emitting units, wherein the ratio of the current value corresponding to the peak value of the light-emitting efficiency of one of the two light-emitting units to the current value corresponding to the peak value of the light-emitting efficiency of the other light-emitting unit is 5-20.

10. The light emitting device according to claim 8, characterized in that: The current value corresponding to the peak value of the luminous efficiency of the light-emitting unit is less than or equal to 0.5 mA.

11. The light emitting device according to claim 1, characterized in that: The ratio of the light emitting area of ​​the second light emitting unit to the light emitting area of ​​the first light emitting unit is 10% to 80%.

12. The light emitting device according to any one of claims 1 to 11, characterized in that: Also includes: The first electrode is disposed on the upper surface of the second semiconductor layer at the uppermost side.

13. The light emitting device according to claim 12, characterized in that: Also includes: The second electrode is disposed on the upper surface of the lowermost portion of the first semiconductor layer that exceeds the edge of the light emitting layer.

14. The light emitting device according to claim 13, characterized in that: The shape of the orthographic projection of the first semiconductor layer on the reference plane is a rectangle, and the reference plane is the plane where the first semiconductor layer located at the bottom is located; Furthermore, in the light-emitting unit located at the lowermost side, the light-emitting layer exposes a corner region of the first semiconductor layer, and the second electrode is disposed at the corner region.

15. The light emitting device according to claim 14, characterized in that: In the orthographic projection onto the reference plane, along the second direction, the second electrode is located on one side of the first semiconductor layer of the second light-emitting unit; and the conductive pattern covers the first boundary of the first semiconductor layer of the corresponding second light-emitting unit, and the first boundary is perpendicular to the second direction and is located between the first electrode and the second electrode.

16. The light emitting device according to claim 14, characterized in that: In an orthographic projection onto the reference plane, the second electrode is located on an extension line of a second boundary of the first semiconductor layer of the second light-emitting unit; and the conductive pattern covers the corresponding second boundary of the first semiconductor layer of the second light-emitting unit.

17. The light emitting device according to any one of claims 1 to 11, characterized in that: Also includes: A conductive substrate, disposed on the upper side of the plurality of light-emitting units; A conductive bonding layer, disposed between the conductive substrate and the plurality of light-emitting units; A first electrode is disposed on a side of the first semiconductor layer farthest from the conductive substrate and away from the conductive substrate; The second electrode is arranged on a side of the conductive substrate away from the plurality of light emitting units.

18. A light-emitting substrate, characterized in that: include: Driver backplane; The light-emitting device according to any one of claims 1 to 17, wherein the light-emitting device is connected to the driving backplane.

19. A display device, characterized in that: Comprising the light emitting substrate as claimed in claim 18.

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