LED light-emitting structure and preparation method thereof

Abstract

The invention discloses an LED light-emitting structure and a preparation method thereof, and relates to the technical field of light-emitting device manufacturing, a substrate of the LED light-emitting structure is provided with a first conductive layer, the first conductive layer comprises a target area exposed out of the first surface of the substrate, the target area is provided with a plurality of target positions where LED chips can be attached more easily, and compared with other parts of the target area, the first conductive layer is provided with a second conductive layer. And the LED chip is easier to attach to a target position. The LED chips are randomly placed in at least the target area of the substrate, the requirement for the position precision of the LED chips is greatly reduced, the production efficiency is improved, the production cost is reduced, normal light emitting can be achieved as long as one effective LED chip exists in the target area, the requirement for the reliability of the LED chips is greatly reduced, the process error-tolerant rate is higher, and the production cost is reduced. The plurality of target positions of the target area are set to be easier to attach the LED chips, so that the positions of the LED chips in the target area are more uniform, and the uniformity of light emission is improved.

Description

Technical Field

[0001] This invention relates to the field of light-emitting device manufacturing technology, and in particular to an LED light-emitting structure and its preparation method. Background Technology

[0002] Display devices comprise a large number of LED chips. For a monochrome display, it includes multiple monochrome pixels, each composed of one LED chip, and all LED chips emit the same color light. For a color display, it includes multiple color pixels, each composed of three LED chips of different colors.

[0003] Existing display devices have very high reliability requirements for LED chips. When a defective LED chip is installed on the screen, or when the LED chip is damaged during use, a certain pixel will not work properly, resulting in a dead pixel on the screen.

[0004] In addition, the manufacturing process of display devices requires the high-precision transfer of a large number of LED chips to designated positions, which places extremely high demands on the precision of the transfer equipment and requires a large number of repetitive transfer operations, resulting in low production efficiency.

[0005] With the development of technology, LED chips can be made smaller and smaller, and the cost can be reduced. However, mass transfer equipment has difficulty accurately adsorbing and releasing smaller LED chips. Moreover, the smaller the LED chip, the more LED chips there are per unit area, requiring a higher transfer speed and higher precision in LED chip placement. However, transfer speed and precision are contradictory. Therefore, existing mass transfer methods are difficult to adapt to increasingly smaller LED chips.

[0006] Therefore, it is necessary to improve the existing technology to overcome the aforementioned defects.

[0007] The above content is only used to help understand the technical solution of this application and does not constitute an admission that the above is prior art. Summary of the Invention

[0008] The purpose of this invention is to provide an LED light-emitting structure and its fabrication method, so as to reduce the requirements for the positional accuracy of LED chips.

[0009] To achieve the above-mentioned objectives, in a first aspect, the present invention provides a method for fabricating an LED light-emitting structure, comprising the following steps:

[0010] S1. A substrate and an LED chip are provided. The substrate has a first conductive layer, the first conductive layer includes a target area exposed on a first surface of the substrate, the target area has a plurality of target positions, and the LED chip is more easily attached to the target positions than other parts of the target area; the LED chip includes an electrode pair, the electrode pair including a first electrode and a second electrode respectively located on two opposite surfaces of the LED chip;

[0011] S2. Randomly place a plurality of LED chips in at least a target area of ​​the substrate, wherein the LED chip whose first electrode is in contact with the target area is a valid LED chip, and the LED chip whose first electrode is not in contact with the target area is an invalid LED chip;

[0012] S3. Prepare a package covering all the LED chips on the substrate;

[0013] S4. A second conductive layer is prepared on top of the package, and the second conductive layer is electrically connected to the second electrode of the effective LED chip.

[0014] Furthermore, in step S2, after randomly placing multiple LED chips in at least a target area of ​​the substrate, all LED chips are retained, or LED chips not located in the target area are removed.

[0015] Furthermore, the first conductive layer includes a plurality of column driving lines spaced apart along a first direction, and the second conductive layer includes a plurality of row driving lines spaced apart along a second direction. The position of the target region corresponds to the overlapping area of ​​the row driving lines and the column driving lines, and the first conductive layer has a plurality of arrayed target regions.

[0016] Furthermore, conductive adhesive is provided at the target location, which makes it easier for the LED chip to adhere to the target location.

[0017] Furthermore, by setting a guiding structure, the LED chip is made easier to attach to the target position. The guiding structure is an auxiliary component, and the auxiliary component has multiple through holes corresponding to the target position.

[0018] Further, in step S2, the step of placing the LED chip in at least the target area of ​​the substrate includes:

[0019] An auxiliary component is disposed on the first surface of the substrate;

[0020] LED chips are randomly distributed on the surface of the auxiliary component, such that at least a portion of the through-hole contains LED chips.

[0021] Furthermore, in step S2, when LED chips are randomly placed in at least the target area of ​​the substrate, LED chips are randomly placed on the entire first surface of the substrate; or, LED chips are randomly placed only in the target area.

[0022] Furthermore, the LED chips are divided into first-color LED chips, second-color LED chips, and third-color LED chips according to their different emission colors, and the target area is divided into a first-color area for carrying the first-color LED chips, a second-color area for carrying the second-color LED chips, and a third-color area for carrying the third-color LED chips;

[0023] In step S2, when LED chips are randomly placed in at least the target area of ​​the substrate, the first color LED chip, the second color LED chip, and the third color LED chip are placed in the corresponding target area.

[0024] Further, in step S2, the step of placing the LED chip in at least the target area of ​​the substrate includes:

[0025] An auxiliary component is provided on the first surface of the substrate. The auxiliary component includes a plurality of first through holes corresponding to the target positions of the first color region, second through holes corresponding to the target positions of the second color region, and third through holes corresponding to the target positions of the third color region.

[0026] First-color LED chips, second-color LED chips, and third-color LED chips are randomly distributed on the surface of the auxiliary component in stages, so that the first-color LED chips, second-color LED chips, and third-color LED chips enter the corresponding through holes.

[0027] Furthermore, when randomly distributing LED chips of a certain color, the through holes that do not correspond to LED chips of that color are blocked.

[0028] Further, in step S2, the step of placing the LED chip in at least the target area of ​​the substrate includes:

[0029] An auxiliary component is provided on the first surface of the substrate. The auxiliary component includes a plurality of first through holes corresponding to the target positions of the first color region, second through holes corresponding to the target positions of the second color region, and third through holes corresponding to the target positions of the third color region. The first through holes, the second through holes, and the third through holes have different sizes and / or cross-sectional shapes. The first color LED chip, the second color LED chip, and the third color LED chip can enter the corresponding through holes, but cannot enter the through holes that do not correspond to them.

[0030] First-color LED chips, second-color LED chips, and third-color LED chips are randomly distributed on the surface of the auxiliary component in stages, so that the first-color LED chips, second-color LED chips, and third-color LED chips enter the corresponding through holes; or, the first-color LED chips, second-color LED chips, and third-color LED chips are randomly distributed on the surface of the auxiliary component at the same time, so that the first-color LED chips, second-color LED chips, and third-color LED chips enter the corresponding through holes.

[0031] Furthermore, the center of gravity of the LED chip is close to the first electrode;

[0032] The LED chip includes a metal mass block connected to its first electrode; and / or,

[0033] The cross-sectional area of ​​the end where the first electrode of the LED chip is located is larger than the cross-sectional area of ​​the end where the second electrode is located.

[0034] Furthermore, the LED chip is in the shape of a cuboid or a cube;

[0035] The LED chip includes two sets of electrode pairs, with the first electrodes of each set of electrode pairs located on two adjacent surfaces of the LED chip; or,

[0036] The LED chip includes three sets of electrode pairs, with the first electrode of each set of electrode pairs located on three adjacent surfaces of the LED chip.

[0037] Secondly, the present invention proposes an LED light-emitting structure, comprising:

[0038] A substrate having a first conductive layer, the first conductive layer including a target area exposed on a first surface of the substrate, the target area having a plurality of target positions for attaching the LED chip;

[0039] The target area is provided with a plurality of LED chips. The positions of the LED chips are random, or the positions and orientations of the LED chips are both random. Each LED chip includes an electrode pair, which includes a first electrode and a second electrode located on opposite surfaces of the LED chip. The LED chip whose first electrode is in contact with the target area is called an effective LED chip, and the remaining LED chips are called ineffective LED chips. The target location is more likely to have the LED chip attached compared to other parts of the target area.

[0040] The package covers the exterior of all the LED chips;

[0041] The second conductive layer is electrically connected to the second electrode of the effective LED chip.

[0042] Furthermore, conductive adhesive is provided at the target location.

[0043] Thirdly, the present invention proposes an LED light-emitting structure, comprising:

[0044] A substrate, wherein the substrate is provided with a first conductive layer, the first conductive layer including a target area exposed on a first surface of the substrate;

[0045] An auxiliary component, connected to the substrate, is provided with multiple through holes;

[0046] LED chips are randomly arranged in a plurality of through holes. Each LED chip includes an electrode pair, which includes a first electrode and a second electrode located on opposite surfaces of the LED chip. The LED chip whose first electrode is in contact with the target area is called an effective LED chip, and the remaining LED chips are called ineffective LED chips.

[0047] The package covers the exterior of all the LED chips;

[0048] The second conductive layer is electrically connected to the second electrode of the effective LED chip.

[0049] Furthermore, the through hole is a tapered hole, and its end near the substrate is the smaller end. The LED chip is tapered, and its smaller end corresponds to the smaller end of the through hole.

[0050] Furthermore, the first conductive layer includes multiple colored pixel regions, each of which includes at least two target regions for carrying LED chips of different emission colors. The LED chips in the same target region emit the same emission color, while the LED chips in different target regions emit different emission colors.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] According to some embodiments of the present invention, the substrate of the LED light-emitting structure is provided with a first conductive layer. The first conductive layer includes a target area exposed on a first surface of the substrate. The target area has multiple target positions that are easier to attach LED chips to, and the LED chips are easier to attach to the target positions compared to other parts of the target area. The LED chips are randomly placed in at least the target area of ​​the substrate, which greatly reduces the positional accuracy requirements for transferring the LED chips, improves production efficiency, and reduces production costs. At the same time, the target area can emit light normally as long as there is one effective LED chip, which greatly reduces the reliability requirements of the LED chips and increases the process fault tolerance. The multiple target positions in the target area are set to be easier to attach LED chips, which helps to make the position of the LED chips in the target area more uniform and improve the uniformity of light emission. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the substrate and the first conductive layer in some embodiments of the present invention.

[0054] Figure 2 yes Figure 1 The diagram shows a top view of the substrate.

[0055] Figure 3 This is a schematic diagram of LED chips in some embodiments of the present invention.

[0056] Figure 4a This is a schematic diagram of a target area where LED chips are randomly placed in some embodiments of the present invention.

[0057] Figure 4b This is a schematic diagram of a target area where LED chips are randomly placed in some embodiments of the present invention.

[0058] Figure 5 yes Figure 1 A schematic diagram showing an LED chip placed on a substrate.

[0059] Figure 6 This is a schematic diagram of several different orientations of LED chips in some embodiments of the present invention.

[0060] Figure 7 yes Figure 5 The diagram shows a structure with an external encapsulation.

[0061] Figure 8 yes Figure 7 The diagram shows a structure with an external insulating layer.

[0062] Figure 9 yes Figure 6 The diagram shown illustrates the structure with a second conductive layer added.

[0063] Figure 10 This is a schematic diagram of LED chips in some embodiments of the present invention.

[0064] Figure 11 This is a schematic diagram of LED chips in some embodiments of the present invention.

[0065] Figure 12 This is a schematic diagram of LED chips in some embodiments of the present invention.

[0066] Figure 13 This is a three-dimensional schematic diagram of an LED chip according to some embodiments of the present invention.

[0067] Figure 14 yes Figure 13The diagram shows the front view of the LED chip.

[0068] Figure 15 This is a three-dimensional schematic diagram of an LED chip according to some embodiments of the present invention.

[0069] Figure 16 This is a schematic diagram of an LED chip in some embodiments of the present invention connected to the first conductive layer via conductive adhesive at a target location.

[0070] Figure 17 This is a schematic diagram of a substrate surface with auxiliary components in some embodiments of the present invention. In the diagram, the through holes are straight holes.

[0071] Figure 18 yes Figure 17 The diagram shows an auxiliary component with an embedded LED chip.

[0072] Figure 19 yes Figure 18 The diagram shown illustrates the structure when the encapsulation is configured.

[0073] Figure 20 yes Figure 19 The diagram shown illustrates the structure with an insulating layer.

[0074] Figure 21 This is a schematic diagram of a substrate surface with auxiliary parts in some embodiments of the present invention. In the diagram, the through hole is in the shape of a conical hole.

[0075] Figure 22 yes Figure 21 The diagram shows an auxiliary component with an embedded LED chip.

[0076] Figure 23 yes Figure 22 The diagram shown illustrates the structure when the encapsulation is configured.

[0077] Figure 24 yes Figure 23 The diagram shown illustrates the structure with an insulating layer.

[0078] Figure 25 This is a schematic diagram of a target area in some embodiments of the present invention carrying LED chips of different colors.

[0079] Figure 26 This is a schematic diagram of some embodiments of the present invention where the entire substrate surface carries LED chips of different colors.

[0080] Figure 27 This is a schematic diagram of a substrate surface having multiple color pixel areas in some embodiments of the present invention.

[0081] Figure 28This is a schematic diagram of some embodiments of the present invention when the second through hole and the third through hole are blocked.

[0082] Figure 29 This is a schematic diagram of some embodiments of the present invention when the first through hole and the third through hole are blocked.

[0083] Figure 30 This is a schematic diagram of some embodiments of the present invention when the first through hole and the second through hole are blocked.

[0084] Figure 31 This is a schematic diagram showing the positions of row driving lines and column driving lines in some embodiments of the present invention. Detailed Implementation

[0085] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0086] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0087] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0088] Some embodiments of the present invention provide a method for fabricating an LED light-emitting structure, which includes the following steps:

[0089] S1. Provides substrate 1 and LED chip 2.

[0090] like Figure 1 and Figure 2As shown, the substrate 1 is provided with a first conductive layer 10, which includes a target area 100 exposed on a first surface of the substrate 1. The target area 100 is provided with a plurality of target positions 101 for attaching the LED chip 2. Figure 2 In the diagram, the approximate location of the target area 100 is indicated by a cross-sectional line, and the approximate location of the target area 100 is indicated by a dashed circle. Compared to other parts of the target area 100, the LED chip 2 is easier to attach to the target location 101.

[0091] LED chip 2 includes electrode pairs, such as Figure 3 As shown, the electrode pair includes a first electrode 20 and a second electrode 21 located on opposite surfaces of the LED chip 2. One of the first electrode 20 and the second electrode 21 is a positive electrode, and the other is a negative electrode. It is understood that the positions of the first electrode 20 and the second electrode 21 determine the direction of current flow to illuminate the LED chip 2. In some embodiments, the LED chip 2 is a vertically oriented LED chip. By using a vertical chip, luminous efficiency can be maintained while significantly reducing the size of the LED chip.

[0092] S2. For example Figures 4a to 5 As shown, multiple LED chips 2 are randomly placed in at least the target area 100 of the substrate 1, so that the presence or absence of an LED chip 2 at each target position 101 is random, that is, it is not necessary for an LED chip 2 to be present at every target position 101, thereby greatly reducing the accuracy and reliability requirements for transferring the LED chips 2.

[0093] In some embodiments, such as Figure 4a As shown, LED chips 2 are randomly placed using a traditional point-to-point mass transfer method. For example, LED chips 2 can be moved using nano-stamping (nano-transfer printing technology). It is only necessary to move LED chips 2 to the target positions 101 at intervals. There is no requirement that LED chips 2 are placed at all target positions 101 in the target area 100. That is, it is not necessary to ensure that LED chips 2 are reliably picked up on every nano-stamp, and it is not required that all target positions 101 have LED chips 2. This greatly reduces the requirements for the reliability and accuracy of the transfer.

[0094] In other embodiments, such as Figure 4bAs shown, LED chips 2 are randomly distributed across at least the target area 100 of the substrate 1 through random placement. In this case, the position and orientation (e.g., electrode orientation) of the LED chips 2 are random. This results in the formation of valid LED chips 2a where the first electrode 20 contacts the target area 100, and invalid LED chips 2b where the first electrode 20 does not contact the target area 100. In other words, random placement includes random scattering. During random placement, the position of the LED chips 2 is random, and the orientation can be random or non-random (depending on the orientation of the LED chips 2 being transported; for example, when transported using a nano-stamp, if the orientation of the transported LED chips 2 is consistent, then the orientation of the LED chips 2 transferred to the target area 100 will also be consistent). During random scattering, both position and orientation are random. Figure 6 The diagram shows the possible orientations of several LED chips 2 when randomly placed. LED chips 2 whose first electrode 20 is in contact with the target area 100 are called effective LED chips 2a because they can be driven to emit light normally. The other LED chips 2 cannot be driven to emit light normally and are called ineffective LED chips 2b.

[0095] S3. For example Figure 7 As shown, a package 3 covering all the LED chips 2 is prepared on the substrate 1.

[0096] The package 3 can be made using existing technologies, such as by injection molding to prepare the package 3 outside the substrate 1.

[0097] S4. For example Figure 8 As shown, a second conductive layer 11 is prepared on the upper surface of the package 3, and the second conductive layer 11 is electrically connected to the second electrode 21 of the effective LED chip 2a.

[0098] Understandably, since the second electrode 21 of the effective LED chip 2a is located on top, it can be easily electrically connected to the second conductive layer 11. Thus, as... Figure 9 As shown, the first electrode 20 and the second electrode 21 of the effective LED chip 2a are electrically connected to the first conductive layer 10 below it and the second conductive layer 11 above it, respectively. With the cooperation of the first conductive layer 10 and the second conductive layer 11, the effective LED chip 2a is lit. For example, when the first electrode 20 is a negative electrode, the first conductive layer 10 is grounded or connected to a low level, and a high-level voltage is applied to the second conductive layer 11, which can drive the effective LED chip 2a to emit light.

[0099] It is understood that the target area 100 corresponds to the area of ​​the first conductive layer 10 covered by the projection of the second conductive layer 11 along the thickness direction of the substrate 1. The positive and negative electrodes at both ends of the effective LED chip 2a in the target area 100 can be electrically connected to the first conductive layer 10 and the second conductive layer 11 respectively, and can be lit up after being powered on.

[0100] It is understandable that although the ineffective LED chip 2b cannot be driven to emit light, as long as there is one luminous LED chip 2 in the target area 100, the target area 100 can achieve the function of emitting light. In addition, under constant current source driving conditions, when the forward conduction voltage (Vf) of multiple parallel LED chips is similar, the total current output by the constant current source is approximately evenly distributed among the LED chips. Since the total current is constant, the total luminous power and overall brightness remain unchanged regardless of the number of parallel LED chips. That is to say, even if the number of effective LED chips 2a on each target area 100 is different, as long as each target area 100 is driven by a constant current source, the luminous brightness of each target area 100 can be nearly consistent. Of course, more accurate consistency can be further optimized through algorithms.

[0101] It is understandable that the more LED chips 2 that can emit light within the target area 100, the more uniform the brightness of the corresponding pixels in that target area will be. Specifically, the target area 100 has multiple target positions 101 that are easier for the LED chips 2 to attach to. Therefore, the probability of the LED chips 2 being located at target positions 101 is higher. Thus, by controlling the arrangement of the target positions 101, the position of the LED chips 2 in the target area 100 can be adjusted, resulting in a more uniform distribution of the LED chips 2 and thus a more uniform brightness in the target area 100. Optionally, the target positions 101 are evenly distributed, such as in an array, which helps prevent the LED chips 2 from clustering together. It is also understood that in some embodiments, target positions 101 may not be provided, and the LED chips 2 can be randomly placed in the target area 100.

[0102] Understandably, since there are usually a large number of effective LED chips 2a in the target area 100, such as two, three or more effective LED chips 2a, when there are two or more LED chips 2, even if there are damaged LED chips 2, the target area 100 can still emit light normally, which greatly reduces the reliability requirements of LED chips 2 and increases the process fault tolerance. For example, in a display screen made of an LED light-emitting structure, even if there are damaged LED chips 2 in the target area 100, as long as there is at least one normally emitting LED chip 2, the entire screen can be displayed normally, reducing the possibility of dead pixels on the screen.

[0103] Understandably, by randomly placing the LED chip 2 in at least the target area 100, the positional requirements for a single LED chip 2 can be greatly reduced, avoiding the high precision requirements of traditional mass transfer, thus greatly improving production efficiency and reducing production costs.

[0104] LED chip 2 can be a Micro LED chip or a Mini LED chip. Since the transfer accuracy requirement is low, the size of LED chip 2 can be made very small, and the cost of a single LED chip 2 is lower. A large number of LED chips 2 can be randomly arranged in a small target area 100, such as a dozen, dozens, hundreds or even more LED chips 2, thereby improving the reliability and uniformity of light emission.

[0105] It is understandable that when a large number of LED chips 2 are randomly distributed, it is almost inevitable that there will be a valid LED chip 2a in the target area 100. In addition, the number of valid LED chips 2a in the target area 100 can be further increased through various means.

[0106] In some embodiments, the center of gravity of the LED chip 2 is set close to the first electrode 20. This makes the LED chip 2 more stable when its first electrode 20 is facing downwards when randomly placed in at least the target area 100, thus significantly increasing the probability that the first electrode 20 of the LED chip 2 is facing downwards. As a possible example, refer to... Figure 10 The LED chip 2 includes a metal mass block 200 connected to its first electrode 20. The center of gravity of the LED chip 2 is changed by adding the metal mass block 200. As a feasible example, such as... Figure 11 As shown, the first electrode 20 of the LED chip 2 is widened and / or thickened to bring its center of gravity closer to the first electrode 20. As a possible example, such as... Figure 12 As shown, the cross-sectional area of ​​the end where the first electrode 20 of the LED chip 2 is located is larger than the cross-sectional area of ​​the end where the second electrode 21 is located, and its overall shape is smaller at the top and larger at the bottom, so that its center of gravity is close to the first electrode 20. It can be understood that the above examples can be used in combination to further ensure the effect.

[0107] In some embodiments, the LED chip 2 is in the shape of a cuboid or a cube, and includes at least two sets of electrode pairs. As described above, each set of electrode pairs includes a first electrode 20 and a second electrode 21 located on opposite surfaces of the LED chip 2, respectively. The first electrodes 20 of the two sets of electrode pairs are located on two adjacent surfaces of the LED chip 2. Similarly, the two second electrodes 21 of the two sets of electrode pairs are also located on two adjacent surfaces of the LED chip 2, respectively. Optionally, the two first electrodes 20 of the two sets of electrode pairs are connected to each other and are integral, for example, extending from one surface of the LED chip 2 to another surface. The two second electrodes 21 of the two sets of electrode pairs are connected to each other and are integral, for example, extending from one surface of the LED chip 2 to another surface. Figure 13 and Figure 14 A schematic diagram is shown when two electrode pairs are provided on the LED chip 2. Since the number of first electrodes 20 on the surface of the LED chip 2 is increased, the probability of the first electrode 20 of the LED chip 2 contacting the target area 100 can be greatly increased. Specifically, assuming that the probability of each side of the LED chip 2 facing down is the same, the probability of having a first electrode 20 facing down is one-sixth when the first electrode 20 is provided on only one side and one-third when the first electrode 20 is provided on both sides.

[0108] In some embodiments, such as Figure 15 As shown, the LED chip 2 includes three sets of electrode pairs. The first electrode 20 of the three sets of electrode pairs is located on three adjacent surfaces of the LED chip 2, and the three first electrodes 10 of the three sets of electrode pairs are located on the other three adjacent surfaces of the LED chip 2. Assuming that the probability of each surface of the LED chip 2 facing down is the same, when three sets of electrode pairs are set, the probability of the first electrode 20 of the LED chip 2 facing down is one in half, which greatly increases the probability. When the number of LED chips 2 randomly distributed in the target area 100 is 10, the probability of having a valid LED chip 2 can be greater than 99.9%. If combined with the aforementioned center of gravity adjustment or other methods, the probability can be further improved. For example, the center of gravity of the LED chip 2 can be set close to one of the first electrodes 20, or it can be set close to the connection position of two or three first electrodes 20. Optionally, the three first electrodes 20 of the three sets of electrode pairs are interconnected and are integral, for example, extending from one surface of the LED chip 2 to the other two surfaces. The three second electrodes 21 of the three sets of electrode pairs are interconnected and are integral, for example, extending from one surface of the LED chip 2 to the other two surfaces.

[0109] Understandably, the probability of the first electrode 20 being on the bottom can be increased in other ways. For example, the probability can be increased by applying an external magnetic field: a small amount of magnetic metal can be deposited on the side of the first electrode 20 or unidirectional magnetic particles can be adhered, and a magnetic field can be applied below the substrate 1 to align the LED chips 2 in the correct orientation. Alternatively, the probability can be increased by applying an external sound field or electric field.

[0110] Optionally, each target area 100 carries no fewer than 8 LED chips 2 to increase the probability of a valid LED chip 2a appearing.

[0111] There are various ways to make the target location 101 easier to attach the LED chip 2 compared to other locations in the target area 100. For example, magnetic force, electrostatic force, adhesive force, mechanical restraint, solder self-alignment, or liquid surface tension can be used to make the target location 101 easier to attach the LED chip 2 compared to other areas. Understandably, once the LED chip 2 is in the target location 101, it will be more difficult to move it from that location.

[0112] In some embodiments, a small amount of magnetic metal or unidirectional magnetic particles can be deposited on the side of the first electrode 20, and a magnetic field can be applied to the area below the substrate 1 corresponding to the target position 101, so that the LED chip 2 can be magnetically attracted to the target position 101.

[0113] In some embodiments, reference Figure 16 Conductive adhesive 5 can be placed at the target position 101. Since the conductive adhesive 5 is sticky, the LED chip 2 in contact with the conductive adhesive 5 is not easy to shift and is more likely to adhere to the target position 101.

[0114] In some embodiments, a groove is provided at the target position 101. Since the LED chip 2 is relatively easier to enter the groove and is more stable in position within the groove, it is also easier to attach to the target position 101.

[0115] In some embodiments, a guiding structure is provided to make it easier for the LED chip 2 to be attached to the target position. For example, an auxiliary member 4 can be provided, which has a plurality of through holes 40 corresponding to the target position 101, making it easier for the LED chip 2 to be confined to the target position 101 through the through holes 40. The auxiliary member 4 can be, for example, plate-shaped or layered.

[0116] Specifically, step S2, which involves placing the LED chip 2 in at least the target region 100 of the substrate 1, includes:

[0117] S20. For example Figure 17As shown, an auxiliary member 4 is provided on the first surface of the substrate 1. The auxiliary member 4 has a plurality of through holes 40 corresponding to the target positions 101. For example, the through holes 40 and the target positions 101 are in a one-to-one correspondence.

[0118] S21. As Figure 17 As shown, LED chips 2 are randomly distributed on the surface of the auxiliary component 4, so that at least part of the through holes 40 can accommodate the LED chips 2.

[0119] In step S21, when LED chips 2 are randomly scattered on the surface of the auxiliary component 4, the LED chips 2 can be tilted onto the surface of the auxiliary component 4 so that the LED chips 2 are randomly embedded in the through holes 40. The LED chips 2 can be driven to move on the surface of the auxiliary component 4 by means of driving the substrate 1 to vibrate or by airflow, so as to increase the probability of the LED chips 2 entering the through holes 40 and enable more through holes 40 to embed LED chips 2 (that is, increase the filling rate of through holes 40). In this way, the light in the target area 100 is more uniform.

[0120] Understandably, the auxiliary component 4 can be retained or removed after the LED chip 2 is connected to the substrate 1. When the auxiliary component 4 needs to be retained, its thickness is set so that the LED chip 2 embedded in the through-hole 40 can protrude outside the auxiliary component 4, so that the top electrode of the LED chip 2 can be electrically connected to the second conductive layer 11. Since the LED chip 2 is only needed in the through-hole 40, the amount of LED chip 2 used is relatively smaller, which helps to reduce costs. Figure 19 It shows Figure 18 A schematic diagram of the package 3 after the structure is formed. Figure 20 It shows Figure 19 A schematic diagram of the structure when the second conductive layer 11 and the insulating layer 12 are formed.

[0121] Optional, such as Figure 21 As shown, the through-hole 40 is tapered, with one end larger than the other. The larger end is called the large end, and the smaller end is called the small end. The small end of the through-hole 40 is closer to the side where the substrate 1 is located. The through-hole 40 can be conical (circular cross-section) or prismatic (polygonal cross-section). Optionally, such as... Figure 22 As shown, the LED chip 2 is adapted to the through hole 40, and the two are configured to be similar in shape so that the LED chip 2 can be reliably embedded in the through hole 40. For example, when the through hole 40 is conical, the LED chip 2 is frustum-shaped; when the through hole 40 is pyramidal, the LED chip 2 is frustum-shaped. Since the LED chip 2 is adapted to the through hole 40, the LED chip 2 can only be embedded in the through hole 40 with its small end facing down. Obviously, the end of the LED chip 2 with a smaller outer diameter is its small end, and the end with a larger outer diameter is its large end. Figure 23 It shows Figure 22A schematic diagram of the package 3 after the structure is formed. Figure 24 It shows Figure 23 A schematic diagram of the structure when the second conductive layer 11 and the insulating layer 12 are formed.

[0122] Since the orientation of LED chip 2 within via 40 is fixed, it is easier to ensure the presence of a valid LED chip 2a.

[0123] It is understandable that the LED chip 2 does not necessarily need to be contoured to the through hole 40 (for example, the cross-section of the through hole 40 can be circular, and the cross-section of the LED chip 2 can be rectangular). As long as the two ends of the LED chip 2 are different sizes, and the larger end of the LED chip 2 cannot enter the smaller end of the through hole 40, while the smaller end of the LED chip 2 can pass through the smaller end of the through hole 40, the LED chip 2 can be inserted into the through hole 40 with its smaller end facing down. Optionally, the larger end of the LED chip 2 cannot enter the through hole 40 to further ensure that the LED chip 2 is not inserted into the through hole 40 in the opposite orientation. Of course, setting the LED chip 2 and the through hole 40 to be contoured can better ensure the relative positional accuracy of the LED chip 2 and the through hole 40, allowing the LED chip 2 to reliably remain vertical and reducing the risk of the LED chip 2 tilting.

[0124] In some embodiments, the center of gravity of the LED chip 2 is set closer to its small end, making it easier to embed into the through-hole 40 with the small end facing down. For example, the mass of the small end can be increased by adding a counterweight to the small end or by thickening the first electrode 20.

[0125] In other embodiments without auxiliary component 4, LED chips 2 not located at target position 101 can be retained or removed. Retention increases the number of effective LED chips 2 present in target area 100, improving the reliability and uniformity of light emission in target area 100, and reducing manufacturing complexity. Removal saves LED chips 2 and reduces costs. For example, LED chips 2 not located at target position 101 can be removed by vibrating the substrate 1 or by blowing air.

[0126] In some embodiments, the LED light-emitting structure is a monochromatic light-emitting structure, in which all LED chips 2 emit the same color, or, as... Figure 25 and Figure 26As shown, each target area 100 of the LED light-emitting structure carries LED chips 2 of different emitting colors. The LED chips 2 in each target area 100 emit the same emitting color after mixing. For example, each target area 100 has three different emitting colors of LED chips 2 to mix and emit light of a fixed color, such as white light. In this case, the LED light-emitting structure can be used as a white backlight or other similar device. In the figure, the letters R, G, and B represent LED chips of different emitting colors.

[0127] When the LED light-emitting structure is a monochromatic light-emitting structure, multiple LED chips 2 can be randomly distributed across the entire surface of the substrate 1, thereby reducing the positional accuracy requirements when randomly distributing the LED chips 2, such as... Figure 26 As shown. Of course, LED chips 2 can also be distributed only in the target area 100, such as... Figure 25 As shown.

[0128] LED chips 2 can be randomly distributed over at least the target area 100 in various ways.

[0129] In some embodiments, the LED chips 2 are directly poured onto at least the target area 100. Specifically, a large number of LED chips 2 can be placed in a storage container, and then the LED chips 2 are released into at least the target area 100 through the storage container. Since the posture of the LED chips 2 in the storage container is random, and the randomness of the LED chips 2 is also increased during the falling process, the LED chips 2 are also randomly distributed after falling into the target area 100. Specifically, the position and posture (e.g., the position of the electrodes) of the LED chips 2 are diverse.

[0130] In other embodiments, randomly distributing the LED chips 2 over at least the target area 100 includes the following steps:

[0131] Multiple LED chips 2 are placed in a liquid to form an LED paste;

[0132] Transfer the LED paste to at least the target area of ​​100.

[0133] It is understandable that the more uniformly the LED chip 2 is distributed in the liquid, the more uniformly the LED chip 2 is distributed in the target area 100 after it is transferred to the target area 100. When the volume of LED paste carried by each target area 100 is similar, the number of LED chips 2 contained in each target area 100 is also relatively similar, which is conducive to increasing the uniformity of light emission.

[0134] Since the orientation of the LED chip 2 in the liquid is random, its position and orientation in the target area 100 are also random after the LED slurry is transferred to the target area 100, resulting in diverse electrode positions. It is understandable that the number of LED chips 2 that may exist in the target area 100 can be controlled by controlling the concentration of the LED chip 2 (i.e., the number of LED chips 2 contained in a unit volume of slurry), thereby controlling the probability of the presence of effective LED chips 2.

[0135] The liquid can be deionized water, an aqueous solution with added surfactants, an organic solvent, or an inert liquid with a density higher than water. Understandably, the liquid does not dissolve, expand, encapsulate, or bond materials, nor does it undergo electrochemical reactions with metals.

[0136] It is understandable that the liquid on substrate 1 can be removed by methods such as solvent evaporation, solution annealing, and capillary drainage. For liquids that can be cured, they can also be cured and retained.

[0137] Optionally, the LED paste can be transferred to the target area 100 by methods such as screen printing, embossing, spraying, or printing. In screen printing, the LED paste is embossed onto the target area 100 using a screen mask. In embossing, the LED paste is first applied to an open stencil and then transferred to the target area 100. In spraying, the LED paste is sprayed onto the surface of the target area 100. Printing can be, for example, inkjet printing or dispensing printing. Of course, when the LED light-emitting structure is a monochromatic light-emitting structure, it can be printed on the entire surface of the substrate 1.

[0138] In some embodiments, the LED light-emitting structure can emit light of different colors, and the LED chip 2 is divided into a first-color LED chip, a second-color LED chip, and a third-color LED chip according to the different colors of its emitted light, such as... Figure 27 As shown, the target area is divided into a first-color region 100a for carrying a first-color LED chip, a second-color region 100b for carrying a second-color LED chip, and a third-color region 100c for carrying a third-color LED chip. The first-color LED chip, the second-color LED chip, and the third-color LED chip can, for example, emit red light, green light, and blue light, respectively. In step S2, when LED chips 2 are randomly placed in at least the target area 100 of the substrate 1, LED chips 2 of different colors (first-color LED chips, second-color LED chips, and third-color LED chips) are placed in their corresponding target areas 100. For example, the first-color LED chip, the second-color LED chip, and the third-color LED chip are placed in the corresponding target areas 100 in stages by tilting or screen printing to prevent the LED chip 2 from being placed in the wrong target area 100.

[0139] When the LED light-emitting structure has LED chips with three different light-emitting colors, as a feasible example, step S2, which involves placing the LED chip 2 in at least the target area 100 of the substrate 1, includes:

[0140] like Figure 28 As shown, an auxiliary member 4 is provided on the first surface of the substrate 1. The auxiliary member 4 includes a plurality of first through holes 40a corresponding to the target position 101 of the first color region 100a, second through holes 40b corresponding to the target position 101 of the second color region 100b, and third through holes 40c corresponding to the target position 101 of the third color region 100c.

[0141] like Figures 29 to 31 As shown, first-color LED chips, second-color LED chips, and third-color LED chips are randomly distributed on the surface of auxiliary component 4 in stages, so that the first-color LED chips, second-color LED chips, and third-color LED chips enter the corresponding through holes, that is, they enter the first through hole 40a, the second through hole 40b, and the third through hole 40c, respectively.

[0142] Optionally, when randomly distributing LED chips 2 of a certain color, the through holes that do not correspond to that color of LED chip can be blocked. For example, when distributing LED chips 2 of the first color, the second through hole 40b and the third through hole 40c can be blocked by the covering material 41. In this way, the first-color LED chip 2 can only enter the first through hole 40a, thus conveniently ensuring the accuracy of the LED chip 2's position. Similarly, when distributing LED chips 2 of the second color, the first through hole 40a and the third through hole 40c can be blocked, and when distributing LED chips of the third color, the first through hole 40a and the second through hole 40b can be blocked.

[0143] Optionally, the first through-hole 40a, the second through-hole 40b, and the third through-hole 40c have different sizes and / or cross-sectional shapes (referring to cross-sections perpendicular to the thickness direction of the substrate 1). The first-color LED chip, the second-color LED chip, and the third-color LED chip can enter their corresponding through-holes, but cannot enter through-holes that do not correspond to them. In this case, the LED chip 2 can enter the corresponding through-hole without the need for a cover 41. Furthermore, the first-color LED chip, the second-color LED chip, and the third-color LED chip can be randomly distributed on the surface of the auxiliary component 4 in stages, allowing them to enter the corresponding through-holes. Alternatively, the first-color LED chip, the second-color LED chip, and the third-color LED chip can be randomly distributed on the surface of the auxiliary component 4 simultaneously, allowing them to enter the corresponding through-holes.

[0144] It is understood that the first conductive layer 10 includes a plurality of target regions 100, which may be distributed in an array to form a large number of dot matrix pixels. Figure 31 In the illustrated embodiment, the LED light-emitting structure includes multiple arrayed target regions 100, specifically arranged in three rows and three columns. The first conductive layer 10 includes multiple column driving lines 102, and the second conductive layer 11 includes multiple row driving lines 112. The column driving lines 102 and row driving lines 112 are staggered, generally perpendicular to each other. As mentioned above, the target regions 100 correspond to the overlapping portions of the column driving lines 102 and row driving lines 112 in the top view direction, and the target regions 100 are a part of the column driving lines 102. By applying a positive voltage to the LED chip 2 within the target regions 100 that need to emit light through the cooperation of the column driving lines 102 and row driving lines 112, independent driving of each target region 100 can be achieved.

[0145] In some embodiments, the LED light-emitting structure has multiple target areas of LED chips 2 carrying different light-emitting colors. For example, it includes a first color area, a second color area, and a third color area, which are arranged alternately in sequence. Three adjacent target areas 100 of different light-emitting colors form a colored pixel area 14. Figure 27 The approximate area of ​​the color pixel region 14 is outlined with a double-dotted line. It can be understood that the first conductive layer 10 may include a large array of color pixel regions 14 to form a display panel. Three column driving lines 102 and one row driving line 112 can drive the three target regions 100 of the color pixel region 14 to emit light independently. For example, when the first electrode 20 is a negative electrode, the row driving line 112 can be controlled to be connected to a high-level voltage, and the column driving line 102 can be controlled to be grounded or connected to a low-level voltage. The voltage and current of the row and column driving lines are coordinated to control the emission of light from each target region 100.

[0146] It is understandable that the LED light-emitting structure may also have only two LED chips 2 with two light-emitting colors. For example, it may have only a first-color LED chip and a second-color LED chip, and correspondingly, a first-color region and a second-color region are provided.

[0147] In some embodiments, the substrate 1 is glass, silicon wafer, ceramic, or a thin film. The thin film is made of an insulating material, such as polyimide (PI, Kapton), polyester film (PET, Mylar), polycarbonate (PC), or polyethylene terephthalate (PEN). The first conductive layer 10 can be, for example, a metal conductive layer, ITO, or a metal mesh. Optionally, both the substrate 1 and the first conductive layer 10 are made of transparent materials.

[0148] In some embodiments, step S3 further includes the following step: thinning the upper surface of the package 3 (e.g., by grinding) to expose the second electrode 21 of the LED chip 2. This ensures that the top electrode of the LED chip 2 can be reliably electrically connected to the second conductive layer 11 during the fabrication of the second conductive layer 11. Optionally, the initial thickness of the second electrode 21 (the thickness before thinning) is not less than 10 μm, so that after the thinning process, as many, or even all, of the second electrodes 21 of the effective LED chips 2a can be reliably exposed, ensuring electrical connection with the second conductive layer 11. It is understood that if the top surface of the LED chip 2 can be reliably exposed during the fabrication of the package 3, the step of thinning the package 3 can be omitted.

[0149] In some embodiments, such as Figure 8 As shown, in step S4, when the second conductive layer 11 is prepared on the upper surface of the package 3, an insulating layer 12 is also formed to cover the second conductive layer 11. The insulating layer 12 can protect the second conductive layer 11. The second conductive layer 11 and the insulating layer 12 can be prepared, for example, by an RDL process. Optionally, the insulating layer 12 and / or the substrate 1 are made of a transparent material so that light can be emitted normally.

[0150] It is understandable that when the substrate 1, the package 3, the insulating layer 12, etc. are all made of transparent materials, and the first conductive layer 11 and the second conductive layer 11 are made of transparent materials or have a thinner line width, the LED light-emitting structure as a whole is transparent and can be used as a transparent display screen for double-sided display.

[0151] This invention proposes an LED light-emitting structure, which can be prepared using the LED light-emitting structure preparation method described above. The structure of the LED light-emitting structure has been described in detail above; the following is a brief description of its main components.

[0152] like Figure 8 As shown, the LED light-emitting structure includes a substrate 1, an LED chip 2, a package 3, and a second conductive layer 11.

[0153] The substrate 1 is provided with a first conductive layer 10, which includes a target area 100 exposed on a first surface of the substrate 1. The target area 100 is provided with a plurality of target positions 101 for attaching LED chip 2. The target positions 101 are set to be easier to attach LED chip 2 than other positions in the target area 100.

[0154] At least a plurality of LED chips 2 are randomly disposed on the target area 100. As described above, the random placement ensures that at least the positions of the LED chips 2 are random, for example, their positions are random, or both their positions and orientations are random. Each LED chip 2 includes an electrode pair, comprising a first electrode 20 and a second electrode 21 located on opposite surfaces of the LED chip 2. LED chips 2 whose first electrode 20 contacts the target area 100 are referred to as effective LED chips 2a, and the remaining LED chips 2 are referred to as ineffective LED chips 2b.

[0155] The package 3 covers the exterior of all LED chips 2.

[0156] The second conductive layer 11 is electrically connected to the second electrode 21 of the effective LED chip 2, and cooperates with the first conductive layer 10 to drive the effective LED chip 2a to emit light. The LED light-emitting structure may also include an insulating layer 12 covering the second conductive layer 11.

[0157] The target position 101 is designed to facilitate the attachment of the LED chip 2, as described above. For example, conductive adhesive can be applied to the target position 101 to increase the resistance to the LED chip 2 detaching from the target position 101. Alternatively, an auxiliary component 4 can be provided to limit the LED chip 2 to the target position 101.

[0158] When the LED light-emitting structure has auxiliary components, such as Figure 20 and Figure 24 As shown, the auxiliary component 4 is connected to the substrate 1 and has multiple through holes 40 corresponding to the target positions. The LED chip 2 protrudes to the outside of the auxiliary component 4 and is electrically connected to the second conductive layer 11. The through hole 40 can be, for example, tapered, with its small end close to the substrate 1. The LED chip 2 is also tapered, with its small end corresponding to the small end of the through hole 40. It is understood that the LED chip 2 is randomly arranged in the multiple through holes 40. For example, only some of the through holes 40 may contain LED chips 2, or all of the through holes 40 may contain LED chips 2.

[0159] like Figure 31 As shown, the first conductive layer 10 includes multiple target regions 100, which can be arranged in an array. The first conductive layer 10 includes multiple spaced column driving lines 102, and the second conductive layer 11 includes multiple spaced row driving lines 112. The column driving lines 102 and row driving lines 112 are staggered, for example, perpendicular to each other. As described above, the target regions 100 correspond to the areas where the column driving lines 102 and row driving lines 112 overlap in the top view. Through the cooperation of the row and column driving lines, the light emission of each target region 100 can be independently controlled.

[0160] In some embodiments, the LED light-emitting structure is a monochromatic light-emitting structure, which can only emit monochromatic light. In this case, it can have LED chips 2 of the same light-emitting color on the entire surface or LED chips 2 of different mixed colors on the entire surface.

[0161] In some embodiments, the LED light-emitting structure is a multi-color light-emitting structure (or a colored light-emitting structure), which can emit light of different colors. The LED chip 2 is divided into a first-color LED chip, a second-color LED chip, and a third-color LED chip according to their emitted colors. The target area is divided into a first-color region 100a for carrying the first-color LED chip, a second-color region 100b for carrying the second-color LED chip, and a third-color region 100c for carrying the third-color LED chip. For example, the first-color LED chip, the second-color LED chip, and the third-color LED chip can emit red light, green light, and blue light, respectively. The first-color region, the second-color region, and the third-color region are arranged alternately. Three adjacent target areas 100 with different emitted colors form a colored pixel area 14. That is, the colored pixel area 14 includes three target areas 100 that respectively carry LED chips 2 of different emitted colors. The LED chips 2 carried in the same target area 100 all emit the same emitted color, while the LED chips 2 carried in different target areas 100 emit different emitted colors. The first conductive layer 10 may include a large number of arrayed colored pixel areas 14.

[0162] It is understandable that an LED light-emitting structure can also have only two LED chips with two light-emitting colors.

[0163] Optionally, the substrate 1, the package 3, and the insulating layer 12 are all made of transparent materials. At the same time, the first conductive layer 11 and the second conductive layer 11 are made of transparent materials or have a thinner line width. The entire LED light-emitting structure is transparent and can be used as a transparent display screen for double-sided display.

[0164] It is understood that other embodiments or structural details of the LED light-emitting structure can be found in the description above, and will not be repeated here.

[0165] It is understood that the target areas, target locations, LED chips, and other structures shown in the accompanying drawings of this specification are illustrative and do not represent the actual form of the product. For example, the target areas, target locations, and the number of LED chips may be fewer or more.

[0166] It should be noted that, in the absence of conflict, the various embodiments described herein can be combined with each other to obtain more implementation schemes.

[0167] The above are merely specific embodiments of the present invention, and any improvements made based on the concept of the present invention shall be considered within the scope of protection of the present invention.

Claims

1. A method for preparing an LED light-emitting structure, characterized in that, Includes the following steps: S1. A substrate (1) and an LED chip (2) are provided. The substrate (1) is provided with a first conductive layer (10). The first conductive layer (10) includes a target area (100) exposed on a first surface of the substrate (1). The target area (100) is provided with a plurality of target positions (101). Compared with other parts of the target area (100), the LED chip (2) is more easily attached to the target positions (101). The LED chip (2) includes an electrode pair. The electrode pair includes a first electrode (20) and a second electrode (21) respectively located on two opposite surfaces of the LED chip (2). S2. Randomly place a plurality of LED chips (2) in at least a target area (100) of the substrate (1), wherein the LED chip (2) whose first electrode (20) is in contact with the target area (100) is a valid LED chip (2a), and the LED chip (2) whose first electrode (20) is not in contact with the target area (100) is an invalid LED chip (2b). S3. Prepare a package (3) covering all the LED chips (2) on the substrate (1); S4. A second conductive layer (11) is prepared on top of the package (3), and the second conductive layer (11) is electrically connected to the second electrode (21) of the effective LED chip (2a).

2. The method for preparing the LED light-emitting structure as described in claim 1, characterized in that, In step S2, after randomly placing multiple LED chips (2) in at least the target area (100) of the substrate (1), all LED chips (2) are retained, or LED chips (2) not in the target area (100) are removed.

3. The method for preparing the LED light-emitting structure as described in claim 1, characterized in that, The first conductive layer (10) includes a plurality of column driving lines (102) spaced apart along a first direction, and the second conductive layer (11) includes a plurality of row driving lines (112) spaced apart along a second direction. The position of the target region (100) corresponds to the overlapping area of ​​the row driving lines (112) and the column driving lines (102). The first conductive layer (10) has a plurality of array-distributed target regions (100).

4. The method for preparing the LED light-emitting structure as described in claim 1, characterized in that, The target location (101) is provided with conductive adhesive (5), and the LED chip (2) is more easily attached to the target location (101) by means of the conductive adhesive (5).

5. The method for preparing the LED light-emitting structure as described in claim 1, characterized in that, By setting a guide structure, the LED chip (2) is more easily attached to the target position (101). The guide structure is an auxiliary component (4), and the auxiliary component (4) is provided with a plurality of through holes (40) corresponding to the target position (101).

6. The method for preparing the LED light-emitting structure as described in claim 5, characterized in that, In step S2, the step of placing the LED chip (2) in at least the target area (100) of the substrate (1) includes: An auxiliary component (4) is provided on the first surface of the substrate (1); LED chips (2) are randomly scattered on the surface of the auxiliary component (4) so ​​that at least part of the through hole (40) contains LED chips (2).

7. The method for preparing the LED light-emitting structure as described in claim 1, characterized in that, In step S2, when LED chips (2) are randomly placed in at least the target area (100) of the substrate (1), LED chips (2) are randomly placed on the entire first surface of the substrate (1); or, LED chips (2) are randomly placed only in the target area (100).

8. The method for preparing the LED light-emitting structure as described in claim 1, characterized in that, The LED chip (2) is divided into a first-color LED chip, a second-color LED chip and a third-color LED chip according to the different colors of its light emission. The target area is divided into a first-color area (100a) for carrying the first-color LED chip, a second-color area (100b) for carrying the second-color LED chip and a third-color area (100c) for carrying the third-color LED chip. In step S2, when LED chips (2) are randomly placed in at least the target area (100) of the substrate (1), the first color LED chip, the second color LED chip and the third color LED chip are placed in the corresponding target area.

9. The method for preparing the LED light-emitting structure as described in claim 8, characterized in that, In step S2, the step of placing the LED chip (2) in at least the target area (100) of the substrate (1) includes: An auxiliary member (4) is provided on the first surface of the substrate (1). The auxiliary member (4) includes a plurality of first through holes (40a) corresponding to the target position (101) of the first color region, second through holes (40b) corresponding to the target position of the second color region, and third through holes (40c) corresponding to the target position of the third color region. First-color LED chips, second-color LED chips, and third-color LED chips are randomly distributed on the surface of the auxiliary component (4) in stages, so that the first-color LED chips, second-color LED chips, and third-color LED chips enter the corresponding through holes.

10. The method for preparing the LED light-emitting structure as described in claim 9, characterized in that, When randomly scattering LED chips of a certain color, block the through holes that do not correspond to LED chips of that color.

11. The method for preparing the LED light-emitting structure as described in claim 8, characterized in that, In step S2, the step of placing the LED chip (2) in at least the target area (100) of the substrate (1) includes: An auxiliary component (4) is provided on the first surface of the substrate (1). The auxiliary component (4) includes a plurality of first through holes (40a) corresponding to the target position (101) of the first color region, second through holes (40b) corresponding to the target position of the second color region, and third through holes (40c) corresponding to the target position of the third color region. The first through holes (40a), the second through holes (40b), and the third through holes (40c) have different sizes and / or cross-sectional shapes. The first color LED chip, the second color LED chip, and the third color LED chip can enter the corresponding through holes, but cannot enter the through holes that do not correspond to them. First-color LED chips, second-color LED chips, and third-color LED chips are randomly distributed on the surface of the auxiliary component (4) in stages, so that the first-color LED chips, second-color LED chips, and third-color LED chips enter the corresponding through holes; or, the first-color LED chips, second-color LED chips, and third-color LED chips are randomly distributed on the surface of the auxiliary component (4) at the same time, so that the first-color LED chips, second-color LED chips, and third-color LED chips enter the corresponding through holes.

12. The method for preparing an LED light-emitting structure according to any one of claims 1 to 11, characterized in that, The center of gravity of the LED chip (2) is close to the first electrode (20). The LED chip (2) includes a metal mass block connected to its first electrode (20); and / or, The cross-sectional area of ​​the end where the first electrode (20) of the LED chip (2) is located is greater than the cross-sectional area of ​​the end where the second electrode (21) is located.

13. The method for preparing the LED light-emitting structure according to any one of claims 1 to 11, characterized in that, The LED chip (2) is in the shape of a cuboid or a cube; The LED chip (2) includes two sets of electrode pairs, with the first electrode (20) of each set of electrode pairs located on two adjacent surfaces of the LED chip (2); or, The LED chip (2) includes three sets of electrode pairs, and the first electrode (20) of the three sets of electrode pairs is located on three adjacent surfaces of the LED chip (2).

14. An LED light-emitting structure, characterized in that, include: The substrate (1) has a first conductive layer (10) and the first conductive layer (10) includes a target area (100) exposed on a first surface of the substrate (1) and the target area (100) has a plurality of target positions (101) for attaching the LED chip (2). LED chips (2), at least the target area (100) is provided with a plurality of LED chips (2), the position of the LED chips (2) is random, or the position and orientation of the LED chips (2) are both random, the LED chips (2) include an electrode pair, the electrode pair includes a first electrode (20) and a second electrode (21) respectively located on two opposite surfaces of the LED chips (2), the LED chips (2) that are in contact with the target area (100) by the first electrode (20) are called effective LED chips (2a), and the remaining LED chips (2) are called ineffective LED chips (2b), the target position (101) is more likely to have the LED chips (2) attached than other parts of the target area (100); The package (3) covers the exterior of all the LED chips (2); The second conductive layer (11) is electrically connected to the second electrode (21) of the effective LED chip (2a).

15. The LED light-emitting structure as described in claim 14, characterized in that, The target location (101) is provided with conductive adhesive.

16. An LED light-emitting structure, characterized in that, include: The substrate (1) is provided with a first conductive layer (10), the first conductive layer (10) including a target area (100) exposed on a first surface of the substrate (1). The auxiliary component (4) is connected to the substrate (1) and has multiple through holes (40). LED chip (2), LED chip (2) is randomly arranged in a plurality of through holes (40), LED chip (2) includes an electrode pair, the electrode pair includes a first electrode (20) and a second electrode (21) respectively located on two opposite surfaces of the LED chip (2), the LED chip (2) whose first electrode (20) contacts the target area (100) is called an effective LED chip (2a), and the remaining LED chips (2) are called ineffective LED chips (2b); The package (3) covers the exterior of all the LED chips (2); The second conductive layer (11) is electrically connected to the second electrode (21) of the effective LED chip (2a).

17. The LED light-emitting structure as described in claim 16, characterized in that, The through hole (40) is a tapered hole, and the end of it closest to the substrate (1) is the small end. The LED chip (2) is tapered, and its small end corresponds to the small end of the through hole (40).

18. The LED light-emitting structure as described in claim 17, characterized in that, The first conductive layer (10) includes multiple color pixel areas (14), each color pixel area (14) includes at least two target areas (100) for carrying LED chips (2) of different emission colors. The emission colors of LED chips (2) on the same target area (100) are the same, and the emission colors of LED chips (2) on different target areas (100) are different.

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