Transfer device and transfer method of micro light-emitting diode

Abstract

The invention provides a micro light-emitting diode transfer device and transfer method, and the device comprises an alignment module which is configured to enable a transfer substrate carrying a plurality of micro light-emitting diodes to directly face a receiving substrate; the receiving substrate comprises a substrate and a plurality of bonding pads arranged on the substrate, and the bonding pads are in one-to-one correspondence with the micro light-emitting diodes; the film forming module is configured to form a water film on the side, facing the transfer substrate, of the receiving substrate; and the transfer module is configured to knock down the micro light-emitting diodes on the transfer substrate onto the receiving substrate, and the micro light-emitting diodes are kept fixed through the water film and are electrically connected with the bonding pads.

Description

Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a transfer device and a transfer method of a micro light emitting diode. Background Art

[0002] Micro LED Display is known as the next generation of display technology, which has the advantages of high efficiency, high brightness, low power consumption, high reliability and long life. This display technology is to make the LED structure thin-film, miniaturized and arrayed, with a size of ≤50um, and then transfer a large number of micro LEDs to the substrate, and after bonding and packaging, form a micro LED display panel. Summary of the invention

[0003] The present disclosure provides a transfer device for a micro light emitting diode, the transfer device comprising:

[0004] An alignment module is configured to align the transfer substrate carrying the plurality of micro-LEDs with a receiving substrate; the receiving substrate comprises a substrate and a plurality of pads arranged on the substrate, the pads corresponding to the micro-LEDs one by one;

[0005] a film forming module configured to form a water film on a side of the receiving substrate facing the transfer substrate;

[0006] The transfer module is configured to knock the micro-LED on the transfer substrate onto the receiving substrate, and the micro-LED is fixed by the water film and is electrically connected to the pad.

[0007] In some embodiments, the film forming module includes: a cooling platform for carrying the second substrate and cooling the receiving substrate to a dew point temperature to form a water film on the receiving substrate, wherein the water film covers the surface of the pad away from the substrate.

[0008] In some embodiments, the micro light emitting diode includes a light emitting body and a connecting electrode, and the connecting electrode is located on a side of the light emitting body away from the transfer substrate;

[0009] The thickness of the water film is greater than the thickness of the connecting electrode, and is less than or equal to half of the total thickness of the light-emitting body and the connecting electrode.

[0010] In some embodiments, the alignment module includes: a carrier, a driving module, a first control module, a second control module and a third control module, wherein:

[0011] The carrying platform comprises a carrying surface facing the cooling module, and the carrying surface is used to carry the transfer substrate;

[0012] The first control module is configured to send a first driving signal to the driving module, so that the driving module adjusts the position of the carrier until the transfer substrate is adjusted to a first target position;

[0013] The second control module is configured to send a second driving signal to the driving module, so that the driving module adjusts the position of the cooling platform until the receiving substrate is adjusted to a second target position;

[0014] The third control module is configured to send a third driving signal to the driving module, so that the driving module moves the transfer substrate according to a position difference between the first target position and the second target position until the transfer substrate faces the receiving substrate.

[0015] In some embodiments, the first control module includes:

[0016] A first image acquisition unit is configured to capture an image of at least a partial area of ​​the transfer substrate;

[0017] The first adjustment unit is configured to obtain a current position of at least one first feature point of the transfer substrate according to the collected image; and send a first driving signal to the driving module according to the current position of at least one first feature point.

[0018] In some embodiments, the second control module includes:

[0019] A second image acquisition unit is configured to acquire an image of at least a partial area of ​​the receiving substrate;

[0020] The second adjustment unit is configured to obtain a current position of at least one second feature point of the receiving substrate according to the collected image; and send a second driving signal to the driving module according to the current position of at least one second feature point.

[0021] In some embodiments, the transfer module includes: a light source configured to irradiate target light to the transfer substrate so that the micro-LEDs are separated from the transfer substrate and fall onto the pad;

[0022] There is an adhesive layer between the micro light emitting diode and the transfer substrate, and the adhesive layer can be debonded or dissociated under the irradiation line of the target light.

[0023] In some embodiments, the target light is ultraviolet light and / or laser light.

[0024] In some embodiments, the transfer substrate is a substrate that is transparent to the target light, so that the target light can pass through the transfer substrate to irradiate the glue layer.

[0025] The present disclosure also provides a method for transferring a micro light emitting diode, the method comprising:

[0026] Aligning the transfer substrate carrying the plurality of micro-LEDs with a receiving substrate; the receiving substrate comprises a substrate and a plurality of pads arranged on the substrate, the pads corresponding to the micro-LEDs one by one;

[0027] forming a water film on a side of the receiving substrate facing the transfer substrate;

[0028] The micro-LED on the transfer substrate is knocked down onto the receiving substrate, and the micro-LED is fixed by the water film and is electrically connected to the pad.

[0029] In some embodiments, forming a water film on a side of the receiving substrate facing the transfer substrate comprises:

[0030] The receiving substrate is cooled to a dew point temperature to form a water film on the receiving substrate, wherein the water film covers a surface of the pad away from the substrate.

[0031] In some embodiments, the micro light emitting diode includes a light emitting body and a connecting electrode, and the connecting electrode is located on a side of the light emitting body away from the transfer substrate;

[0032] The thickness of the water film is greater than the thickness of the connecting electrode, and is less than or equal to half of the total thickness of the light-emitting body and the connecting electrode.

[0033] In some embodiments, placing the transfer substrate carrying the plurality of micro-LEDs opposite to the receiving substrate comprises:

[0034] adjusting the transfer substrate to a first target position;

[0035] adjusting the receiving substrate to a second target position;

[0036] According to the position difference between the first target position and the second target position, the transfer substrate is moved until the transfer substrate is directly opposite to the receiving substrate.

[0037] In some embodiments, adjusting the transfer substrate to a first target position includes:

[0038] capturing an image of at least a partial area of ​​the transfer substrate;

[0039] Acquire a current position of at least one first feature point of the transfer substrate according to the acquired image;

[0040] The position of the transfer substrate is adjusted according to the current position of at least one of the first feature points until the transfer substrate is adjusted to the first target position.

[0041] In some embodiments, adjusting the receiving substrate to a second target position includes:

[0042] Acquiring an image of at least a partial area of ​​the receiving substrate;

[0043] Acquire a current position of at least one second feature point of the receiving substrate according to the acquired image;

[0044] The position of the receiving substrate is adjusted according to the current position of at least one of the second feature points until the receiving substrate is adjusted to the second target position.

[0045] In some embodiments, knocking the micro LEDs on the transfer substrate onto the receiving substrate comprises:

[0046] irradiating the transfer substrate with target light so that the micro light emitting diode is separated from the transfer substrate and falls on the pad;

[0047] There is an adhesive layer between the micro-LED and the transfer substrate, and the adhesive layer can be debonded or dissociated under the irradiation of the target light.

[0048] In some embodiments, the target light is ultraviolet light and / or laser light.

[0049] In some embodiments, the transfer substrate is a substrate that is transparent to the target light, so that the target light can pass through the transfer substrate to irradiate the glue layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0051] Figure 1 A schematic diagram of the structure of a transfer device provided in an embodiment of the present disclosure.

[0052] Figure 2 A schematic diagram of the structure of a transfer device before alignment provided in an embodiment of the present disclosure.

[0053] Figure 3 for Figure 2 Schematic diagram of the position adjustment principle of the transfer substrate in the embodiment.

[0054] Figure 4 for Figure 2 Schematic diagram of the position adjustment principle of the receiving substrate in the embodiment.

[0055] Figure 5 It is a partial structural schematic diagram of a transfer device in an alignment state provided in an embodiment of the present disclosure.

[0056] Figure 6 A schematic diagram of transferring a micro light emitting diode to a receiving substrate provided in an embodiment of the present disclosure.

[0057] Figure 7 It is a partial structural schematic diagram of a transfer device provided in an embodiment of the present disclosure.

[0058] Figure 8 A partial structural schematic diagram of another transfer device provided in an embodiment of the present disclosure.

[0059] Fig. 9 This is a partial structural schematic diagram of another transfer device provided in an embodiment of the present disclosure.

[0060] Fig.10 The present invention is a flow chart of a light emitting diode transfer method provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0061] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0062] In this specification, for the sake of convenience, the words and phrases indicating the orientation or positional relationship such as "middle", "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like are used to illustrate the positional relationship of the constituent elements with reference to the drawings. This is only for the purpose of facilitating the description of this specification and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation of the present disclosure. The positional relationship of the constituent elements is appropriately changed according to the direction in which each constituent element is described. Therefore, it is not limited to the words and phrases described in the specification and can be appropriately replaced according to the situation.

[0063] Unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The words "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. The terms "install", "connect" and "connect" should be understood in a broad sense. For example, it can be fixedly connected, or detachably connected, or connected in one piece; it can be mechanically connected, or connected; it can be directly connected, or indirectly connected through an intermediate, or the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0064] At present, the mass transfer technology of micro-LEDs such as Micro-LED and Mini-LED is widely used. Among them, the transfer process of micro-LEDs includes: setting a plurality of micro-LEDs on the side of the transfer substrate facing the receiving substrate, and setting a plurality of pads on the side of the receiving substrate facing the transfer substrate. Then, the micro-LEDs on the transfer substrate are laser-lifted (LLO) or peeled off by other means, so that the micro-LEDs are transferred to the receiving substrate, and the pins of the micro-LEDs transferred to the receiving substrate must be oriented correctly and stably electrically connected to the pads on the receiving substrate.

[0065] Figure 1 FIG. 1 is a schematic diagram of a structure of a transfer device in an alignment state provided in an embodiment of the present disclosure, such as Figure 1 As shown, the present disclosure provides a transfer device for micro-LEDs, the transfer device comprising: an alignment module 1, a film forming module 2, and a transfer module 3. The alignment module 1 is configured to align a transfer substrate 4 carrying a plurality of micro-LEDs with a receiving substrate 5, wherein the receiving substrate 5 comprises a substrate 500 and a plurality of pads 501 arranged on the substrate 500, and the pads 501 correspond to the micro-LEDs 7 one by one. The alignment module can make the transfer substrate 4 and the receiving substrate 5 face each other, thereby preventing some micro-LEDs on the transfer substrate from falling outside the receiving substrate 5.

[0066] The film forming module 2 is configured to form a water film 8 on the side of the receiving substrate 5 facing the transfer substrate 4 .

[0067] The transfer module is configured to knock the micro LED 7 on the transfer substrate onto the receiving substrate 5 . The micro LED 7 is fixed by the water film 8 and is electrically connected to the pad 501 .

[0068] In the disclosed embodiment, the film forming module 2 can form a water film 8 on the receiving substrate 5. The surface of the water film 8 has a certain tension, which can increase the intermolecular force between the micro-LED 7 and the pad 501, and receive and temporarily fix the fallen micro-LED 7. In addition, the setting of the water film 8 can also solve the problem of introducing new materials due to the inability to fix the micro-LED 7, thereby increasing the process and cost. Therefore, the setting of the water film 8 is not only simple and effective in process, which can reduce production costs, but also can improve the transfer efficiency of the micro-LED 7.

[0069] In some embodiments, Figure 1 As shown, the film forming module 2 includes a cooling platform 201 , wherein the cooling platform 201 is used to carry the receiving substrate 5 and cool the receiving substrate 5 to a dew point temperature to form a water film 8 on the receiving substrate 5 , and the water film 8 covers the surface of the pad 501 away from the substrate 500 .

[0070] It should be noted that the dew point temperature refers to the temperature at which the air is cooled to saturation under the condition that the water vapor content in the air remains unchanged and the air pressure is kept constant. The unit of the dew point temperature is ℃.

[0071] The water film 8 may only cover the surface of the pad 501 away from the substrate 500. When the receiving substrate 5 is cooled to the dew point temperature, a layer of fine water droplets condenses on the surface of the pad 501. After a period of time, the water droplets are connected to form a water film 8 with a smooth surface. The position of the receiving substrate 5 corresponding to the spacing area of ​​the pad 501 may be formed with a water film 8, or may not be formed with a water film 8. However, it should be noted that in actual production, the cooling temperature and / or cooling time may be controlled so that when the water film 8 is formed in the spacing area of ​​the pad 501, the water film 8 in the spacing area is not connected to the water film 8 on the surface of the pad 501, so as to prevent the micro-LED 7 from moving on the surface of the pad 501 with the water flow.

[0072] In some embodiments, the micro-LED 7 includes a light-emitting body 701 and a connecting electrode 702, and the connecting electrode 702 is used to connect to the pad 501; after the micro-LED 7 is aligned with the pad 501, the orthographic projection of the connecting electrode 702 on the pad 501 is located within the orthographic projection range of the water film 8 on the pad 501, so as to ensure the fixing stability of the micro-LED 7 on the pad 501.

[0073] In some embodiments, the micro-LED 7 includes a light-emitting body 701 and a connecting electrode 702, the connecting electrode 702 is used to connect to the pad 501; the orthographic projection area of ​​the pad 501 on the substrate 500 is larger than the orthographic projection area of ​​the connecting electrode 702 on the transfer substrate 4; and, after the micro-LED 7 is aligned with the pad 501, the orthographic projection of the connecting electrode 702 on the substrate 500 is located within the orthographic projection range of the water film 8 on the substrate 500, so as to ensure the fixing stability of the micro-LED 7 on the pad 501.

[0074] In some embodiments, the micro-LED 7 includes a light-emitting body 701 and a connecting electrode 702, and the connecting electrode 702 is used to connect to the pad 501; when the micro-LED 7 is aligned with the pad 501, the orthographic projection of the connecting electrode 702 on the substrate 500 is located within the orthographic projection range of the pad 501 on the substrate 500; and, when the micro-LED 7 is aligned with the pad 501, the orthographic projection of the connecting electrode 702 on the substrate 500 is located within the orthographic projection range of the water film 8 on the substrate 500, so as to ensure the fixing stability of the micro-LED 7 on the pad 501.

[0075] In some embodiments, after the micro-LED 7 is aligned with the pad 501 , the orthographic projection of the pad 501 on the substrate 500 is located within the orthographic projection range of the water film 8 on the substrate 500 .

[0076] In some embodiments, Figure 1 As shown, the micro light emitting diode 7 includes a light emitting body 701 and a connecting electrode 702 . The connecting electrode 702 is located on a side of the light emitting body 701 away from the transfer substrate 4 .

[0077] Among them, the thickness of the water film 8 is greater than the thickness of the connecting electrode 702, and is less than or equal to half of the total thickness of the light-emitting body 701 and the connecting electrode 702. Among them, if the thickness of the water film 8 is too thick, the micro-LED 7 will be suspended on the water film 8, and then the micro-LED 7 suspended on the water film 8 will deviate from the original position due to factors such as vibration, thereby causing position deviation and poor transfer. The thickness of the water film 8 should not be too thin. If the thickness of the water film 8 is too thin, the fixing effect of the micro-LED 7 will be poor, and the position of the micro-LED 7 will be affected by external factors, resulting in position deviation and poor transfer. In the embodiment of the present disclosure, the thickness of the water film 8 is greater than the thickness of the connecting electrode 702, and is less than or equal to half of the total thickness of the light-emitting body 701 and the connecting electrode 702, which can improve the fixing stability of the micro-LED 7 on the surface of the pad 501.

[0078] In one example, the total thickness of the light-emitting body 701 and the connecting electrode 702 (that is, the total thickness of the micro-LED 7) ranges from 6um to 8.5um, the thickness of the connecting electrode 702 ranges from 1μm to 2μm, and the thickness of the water film ranges from 4μm to 7.5μm. Therefore, the receiving substrate 5 only needs a thin layer of water film 8 to complete the fixation.

[0079] Figure 2 This is a schematic diagram of the structure of a transfer device before alignment provided by an embodiment of the present disclosure. Figure 3 for Figure 2 The principle diagram of the position adjustment of the transfer substrate in the embodiment, Figure 4 for Figure 2 The principle diagram of position adjustment of the receiving substrate in the embodiment, Figure 5 FIG. 1 is a partial structural diagram of a transfer device in an alignment state provided in an embodiment of the present disclosure, such as Figures 1 to 5 As shown, in some embodiments, the alignment module 1 includes: a carrier 101, a driving module 102, a first control module 103, a second control module 104 and a third control module 105. The carrier 101 includes a carrier surface facing the cooling module 201, and the carrier surface is used to carry the transfer substrate 4.

[0080] The first control module 103 is configured to send a first drive signal to the drive module 102, so that the drive module 102 adjusts the position of the carrier 101 until the transfer substrate 4 is adjusted to the first target position. The second control module 104 is configured to send a second drive signal to the drive module 102, so that the drive module 102 adjusts the position of the cooling platform 201 until the receiving substrate 5 is adjusted to the second target position.

[0081] In some embodiments, Figure 2 As shown, the first control module 103 includes a first image acquisition unit 103a and a first adjustment unit 103d, wherein the first image acquisition unit 103a is configured to acquire an image of at least a partial area of ​​the transfer substrate 4. The first adjustment unit 103d is configured to acquire the current position of at least one first feature point of the transfer substrate 4 according to the acquired image; and send a first driving signal to the driving module 102 according to the current position of the at least one first feature point.

[0082] like Figure 2As shown, the first image acquisition unit 103a may include multiple cameras, and the first feature point may include the spatial position coordinates of two endpoints of any diagonal line of the transfer substrate 4. For example, in some embodiments, the first image acquisition unit 103a includes two cameras, namely, a first camera 103b and a second camera 103c, wherein the first camera 103b and the second camera 103c are used to capture images of at least a partial area of ​​the current transfer substrate 4, and the first adjustment unit 103d acquires the spatial position coordinates M1 and M2 of two endpoints of any diagonal line of the current transfer substrate 4 according to the images captured by the first camera 103b and the second camera 103c, and uses the position coordinates M1 and M2 as endpoint values ​​to determine a current diagonal line of the transfer substrate 4, which are recorded as first calibration marks.

[0083] like Figure 2 and Figure 3 As shown, the first adjustment unit 103d is preset with the position coordinates M3 and M4 of the two end points of one of the preset diagonals of the transfer substrate 4, and the preset diagonal is recorded as the first alignment mark. The angle α between the first alignment mark and the first calibration mark is obtained. When the angle α is not 0, the first adjustment unit 103d sends a first driving signal to the driving module 102, so that the driving module 102 adjusts the position of the carrier 101, and then adjusts the position of the transfer substrate 4, until the value of the angle α is adjusted to 0, so that the transfer substrate 4 is adjusted from the current position to the first target position.

[0084] In some embodiments, Figure 2 As shown, the second control module 104 includes a second image acquisition unit 104a and a second adjustment unit 104d, wherein the second image acquisition unit 104a is configured to acquire an image of at least a partial area of ​​the receiving substrate 5. The second adjustment unit 104d is configured to acquire the current position of at least one second feature point of the receiving substrate 5 according to the acquired image; and send a second driving signal to the driving module 102 according to the current position of the at least one second feature point.

[0085] like Figure 2As shown, the second image acquisition unit 104a may include multiple cameras, and the second feature point may include the spatial position coordinates of two endpoints of any diagonal line of the receiving substrate 5. For example, in some embodiments, the second image acquisition unit 104a includes two cameras, namely, a third camera 104b and a fourth camera 104c, wherein the third camera 104b and the fourth camera 104c are used to capture images of at least a partial area of ​​the current receiving substrate 55, and the second adjustment unit 104d acquires the spatial position coordinates N1 and N2 of two endpoints of any diagonal line of the current receiving substrate 5 according to the images captured by the third camera 104b and the fourth camera 104c, and uses the position coordinates N1 and N2 as endpoint values ​​to determine a current diagonal line of the receiving substrate 5, which is recorded as a second calibration mark.

[0086] like Figure 2 and Figure 4 As shown, the second adjustment unit 104d is preset with the position coordinates N3 and N4 of the two end points of one of the preset diagonals of the receiving substrate 5, and the preset diagonal is recorded as the second alignment mark. An angle β is obtained between the second alignment mark and the second calibration mark. When the angle β is not 0, the second adjustment unit 104d sends a second driving signal to the driving module 102, so that the driving module 102 adjusts the position of the current cooling platform 201, and then adjusts the position of the receiving substrate 5, until the value of the angle β is adjusted to 0, so that the receiving substrate 5 is adjusted from the current position to the second target position.

[0087] The third control module 105 is configured to send a third driving signal to the driving module 102 so that the driving module 102 moves the transfer substrate 4 according to the position difference between the first target position and the second target position until the transfer substrate 4 faces the receiving substrate 5 .

[0088] For example, Figure 3 and Figure 4 As shown, the first adjustment unit 103d obtains the position coordinate O1 of the center point of any diagonal line of the transfer substrate 4 according to the first alignment mark; the second adjustment unit 104d obtains the position coordinate O3 of the center point of any diagonal line of the receiving substrate 5 according to the second alignment mark. The third control module obtains the position difference between the position coordinate O1 and the position coordinate O3, and sends a third driving signal to the driving module 102, so that the driving module 102 moves the transfer substrate 4 according to the position difference until the transfer substrate 4 and the receiving substrate 5 are aligned, thereby realizing the alignment of the transfer substrate 4 and the receiving substrate 5.

[0089] In the disclosed embodiment, by aligning the transfer substrate 4 and the receiving substrate 5 , the micro LEDs 7 on the transfer substrate 4 can be accurately transferred to the pads 501 on the receiving substrate 5 corresponding to the micro LEDs 7 .

[0090] In the above embodiment, the first adjustment unit 103d, the second adjustment unit 104d, and the third control module 105 may be integrated into the same controller.

[0091] Figure 6 A schematic diagram of transferring a micro light emitting diode to a receiving substrate provided in an embodiment of the present disclosure is shown in FIG. Figure 6 As shown, in some embodiments, the transfer module 3 includes a light source 301, and the light source 301 is configured to irradiate target light to the transfer substrate 4, so that the micro-LED 7 is separated from the transfer substrate 4 and falls on the pad 501. There is an adhesive layer 6 between the micro-LED 7 and the transfer substrate 4, and the adhesive layer 6 can be reduced in viscosity or dissociated under the irradiation line of the target light, so that the micro-LED 7 on the transfer substrate 4 can be separated from the transfer substrate 4, and then fall on the receiving substrate 5.

[0092] In some embodiments, the target light is ultraviolet light and / or laser. For example, the target light is ultraviolet light, and the adhesive layer 6 can be an ultraviolet light-dissociated adhesive. For another example, the target light is laser, and the adhesive layer 6 can be a laser-dissociated adhesive.

[0093] In one example, if Figure 6 As shown, the transfer module 3 may also include a beam expander 302, a spot shaper 303, a first galvanometer 304, a second galvanometer 305, and a field lens 306. Among them, the light source 301 is a laser generator for generating laser light. According to the implementation requirements, the specific type of the laser generator may be a gas laser, a solid laser, a semiconductor laser, a dye laser, etc. The spot shaper 303 is used to shape the spot formed by the target light emitted by the light source 301, so that the spot formed by the target light is converted from a Gaussian spot to a flat-top spot. The first galvanometer 304 and the second galvanometer 305 are a vector scanning device that can deflect the target light in different predetermined dimensions to achieve different processing actions. The field lens 306 is used to focus the target light, control the effective area of ​​the target light, and then irradiate the flat-top spot to the corresponding position of the transfer substrate 4, so as to achieve the dissociation of the dissociated glue on the transfer substrate 4, and make the micro-light-emitting diode 7 fall onto the receiving substrate.

[0094] In some embodiments, Figures 1 to 6 As shown, the transfer substrate 4 is a substrate that is transparent to the target light, so that the target light can pass through the transfer substrate 4 and irradiate the glue layer 6 .

[0095] Figure 7 is a partial structural schematic diagram of a transfer device provided in an embodiment of the present disclosure, Figure 8 It is a partial structural schematic diagram of another transfer device provided in an embodiment of the present disclosure, Fig. 9It is a partial structural schematic diagram of another transfer device provided in an embodiment of the present disclosure, Fig.10 Flow chart of a light emitting diode transfer method provided in an embodiment of the present disclosure, such as Figures 7 to 10 As shown, the present disclosure also provides a method for transferring a micro light emitting diode, which can be performed by the above-mentioned transfer device. The method for transferring a micro light emitting diode comprises the following steps:

[0096] S1. Align the transfer substrate carrying a plurality of micro-LEDs with the receiving substrate; the receiving substrate comprises a substrate and a plurality of pads arranged on the substrate, and the pads correspond to the micro-LEDs one by one.

[0097] S2. Forming a water film on the side of the receiving substrate facing the transfer substrate.

[0098] S3. Knock the micro-LED on the transfer substrate onto the receiving substrate. The micro-LED is fixed by the water film and is electrically connected to the pad.

[0099] In some embodiments, Figure 8 As shown, forming a water film 8 on the side of the receiving substrate facing the transfer substrate 4 includes the following steps:

[0100] S21 , cooling the receiving substrate to a dew point temperature to form a water film on the receiving substrate, wherein the water film covers the surface of the pad away from the substrate.

[0101] Among them, cooling the receiving substrate 5 to the dew point temperature to form a water film 8 on the receiving substrate 5 means that before transferring the micro-LED on the transfer substrate 4 to the receiving substrate 5, the receiving substrate is cooled to the dew point temperature T through a cooling platform, and then the temperature is slowly lowered. A water film 8 will first be formed on the metal pad on the receiving substrate 5. When the water film 8 reaches the required thickness, the receiving substrate 5 is placed at a constant temperature T' for a certain period of time, and the micro-LED on the transfer substrate 4 is knocked down. At this time, the temperature of the cooling platform is fluctuated between the dew point temperature T and the constant temperature T' to maintain the thickness of the water film 8.

[0102] In some embodiments, the micro-LED 7 includes a light-emitting body 701 and a connecting electrode 702, wherein the connecting electrode 702 is located on a side of the light-emitting body 701 away from the transfer substrate 4. The thickness of the water film 8 is greater than the thickness of the connecting electrode 702, and is less than or equal to half of the total thickness of the light-emitting body 701 and the connecting electrode 702.

[0103] In some embodiments, Figure 7 As shown, placing the transfer substrate 4 carrying a plurality of micro-LEDs 7 opposite to the receiving substrate 5 includes the following steps:

[0104] S10, adjusting the transfer substrate to a first target position.

[0105] S11, adjusting the receiving substrate to a second target position.

[0106] S12, according to the position difference between the first target position and the second target position, move the transfer substrate 4 until the transfer substrate is directly opposite to the receiving substrate.

[0107] In some embodiments, adjusting the transfer substrate 4 to the first target position includes the following steps:

[0108] S100, capturing an image of at least a partial area of ​​a transfer substrate.

[0109] S101 . Acquire a current position of at least one first feature point of a transfer substrate according to a collected image.

[0110] S102 . Adjust the position of the transfer substrate 4 according to the current position of at least one first feature point, until the transfer substrate is adjusted to a first target position.

[0111] In some embodiments, adjusting the receiving substrate 5 to the second target position includes the following steps:

[0112] S110, capturing an image of at least a partial area of ​​a receiving substrate.

[0113] S111. Acquire a current position of at least one second feature point of the receiving substrate according to the acquired image.

[0114] S112. Adjust the position of the receiving substrate according to the current position of the at least one second feature point until the receiving substrate is adjusted to a second target position.

[0115] In some embodiments, Fig. 9 As shown, knocking down the micro-LED 7 on the transfer substrate 4 onto the receiving substrate 5 includes the following steps:

[0116] S30, irradiating the transfer substrate with target light, so that the micro light emitting diodes are separated from the transfer substrate 4 and fall onto the pads.

[0117] There is an adhesive layer 6 between the micro-LED 7 and the transfer substrate 4, and the adhesive layer 6 can be debonded or dissociated under the irradiation of the target light.

[0118] In some embodiments, the target light is ultraviolet light and / or laser light.

[0119] In some embodiments, the transfer substrate 4 is a substrate that is transparent to the target light, so that the target light can pass through the transfer substrate 4 and irradiate the adhesive layer 6 .

[0120] The principle of the transfer process of the micro-LED 7 is described in the above description of the transfer device, which will not be repeated here.

[0121] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A transfer device for a micro light emitting diode, characterized in that: The transfer device comprises: An alignment module is configured to align the transfer substrate carrying the plurality of micro-LEDs with a receiving substrate; the receiving substrate comprises a substrate and a plurality of pads arranged on the substrate, the pads corresponding to the micro-LEDs one by one; a film forming module configured to form a water film on a side of the receiving substrate facing the transfer substrate; The transfer module is configured to knock the micro-LED on the transfer substrate onto the receiving substrate, and the micro-LED is fixed by the water film and is electrically connected to the pad.

2. The transfer device according to claim 1, characterized in that The film forming module comprises: a cooling platform for carrying the second substrate and cooling the receiving substrate to a dew point temperature to form a water film on the receiving substrate, wherein the water film covers the surface of the pad away from the substrate.

3. The transfer device according to claim 1, characterized in that The micro light emitting diode comprises a light emitting body and a connecting electrode, wherein the connecting electrode is located at a side of the light emitting body away from the transfer substrate; The thickness of the water film is greater than the thickness of the connecting electrode, and is less than or equal to half of the total thickness of the light-emitting body and the connecting electrode.

4. The transfer device according to claim 1, characterized in that: The alignment module includes: a carrier, a driving module, a first control module, a second control module and a third control module, wherein: The carrying platform comprises a carrying surface facing the cooling module, and the carrying surface is used to carry the transfer substrate; The first control module is configured to send a first driving signal to the driving module, so that the driving module adjusts the position of the carrier until the transfer substrate is adjusted to a first target position; The second control module is configured to send a second driving signal to the driving module, so that the driving module adjusts the position of the cooling platform until the receiving substrate is adjusted to a second target position; The third control module is configured to send a third driving signal to the driving module, so that the driving module moves the transfer substrate according to a position difference between the first target position and the second target position until the transfer substrate faces the receiving substrate.

5. The transfer device according to claim 4, characterized in that The first control module comprises: A first image acquisition unit is configured to capture an image of at least a partial area of ​​the transfer substrate; The first adjustment unit is configured to obtain a current position of at least one first feature point of the transfer substrate according to the collected image; and send a first driving signal to the driving module according to the current position of at least one first feature point.

6. The transfer device according to claim 4, characterized in that The second control module includes: A second image acquisition unit is configured to acquire an image of at least a partial area of ​​the receiving substrate; The second adjustment unit is configured to obtain a current position of at least one second feature point of the receiving substrate according to the collected image; and send a second driving signal to the driving module according to the current position of at least one second feature point.

7. The transfer device according to any one of claims 1 to 6, characterized in that The transfer module comprises: a light source, the light source being configured to irradiate target light to the transfer substrate so that the micro-LED is separated from the transfer substrate and falls on the pad; There is an adhesive layer between the micro light emitting diode and the transfer substrate, and the adhesive layer can be debonded or dissociated under the irradiation line of the target light.

8. The transfer device according to claim 7, characterized in that The target light is ultraviolet light and / or laser.

9. The transfer device according to claim 7, characterized in that: The transfer substrate is a substrate that is transparent to the target light, so that the target light can pass through the transfer substrate and irradiate the adhesive layer.

10. A method for transferring a micro light emitting diode, characterized in that: The transfer method of the micro light emitting diode comprises: Aligning the transfer substrate carrying the plurality of micro-LEDs with a receiving substrate; the receiving substrate comprises a substrate and a plurality of pads arranged on the substrate, the pads corresponding to the micro-LEDs one by one; forming a water film on a side of the receiving substrate facing the transfer substrate; The micro-LED on the transfer substrate is knocked down onto the receiving substrate, and the micro-LED is fixed by the water film and is electrically connected to the pad.

11. The method for transferring a micro light emitting diode according to claim 10, characterized in that: Forming a water film on a side of the receiving substrate facing the transfer substrate comprises: The receiving substrate is cooled to a dew point temperature to form a water film on the receiving substrate, wherein the water film covers a surface of the pad away from the substrate.

12. The method for transferring a micro light emitting diode according to claim 10, characterized in that: The micro light emitting diode comprises a light emitting body and a connecting electrode, wherein the connecting electrode is located at a side of the light emitting body away from the transfer substrate; The thickness of the water film is greater than the thickness of the connecting electrode, and is less than or equal to half of the total thickness of the light-emitting body and the connecting electrode.

13. The method for transferring a micro light emitting diode according to claim 10, characterized in that: Placing the transfer substrate carrying the plurality of micro-LEDs opposite to the receiving substrate comprises: adjusting the transfer substrate to a first target position; adjusting the receiving substrate to a second target position; According to the position difference between the first target position and the second target position, the transfer substrate is moved until the transfer substrate is directly opposite to the receiving substrate.

14. The method for transferring a micro light emitting diode according to claim 13, characterized in that: Adjusting the transfer substrate to a first target position includes: capturing an image of at least a partial area of ​​the transfer substrate; Acquire a current position of at least one first feature point of the transfer substrate according to the acquired image; The position of the transfer substrate is adjusted according to the current position of at least one of the first feature points until the transfer substrate is adjusted to the first target position.

15. The method for transferring a micro light emitting diode according to claim 13, characterized in that: Adjusting the receiving substrate to a second target position includes: Acquiring an image of at least a partial area of ​​the receiving substrate; Acquire a current position of at least one second feature point of the receiving substrate according to the acquired image; The position of the receiving substrate is adjusted according to the current position of at least one of the second feature points until the receiving substrate is adjusted to the second target position.

16. The method for transferring a micro light emitting diode according to any one of claims 10 to 15, characterized in that: The method comprises: knocking down the micro light emitting diode on the transfer substrate onto the receiving substrate, comprising: irradiating the transfer substrate with target light so that the micro light emitting diode is separated from the transfer substrate and falls on the pad; There is an adhesive layer between the micro-LED and the transfer substrate, and the adhesive layer can be debonded or dissociated under the irradiation of the target light.

17. The method for transferring a micro light emitting diode according to claim 16, characterized in that: The target light is ultraviolet light and / or laser.

18. The method for transferring a micro light emitting diode according to claim 16, characterized in that: The transfer substrate is a substrate transparent to the target light, so that the target light can pass through the transfer substrate and irradiate the adhesive layer.

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