Transfer device and manufacturing method thereof, micro-led transfer method and display

Abstract

Embodiments of the present application provide a transfer device and a manufacturing method thereof, a micro-LED transfer method and a display. The transfer device comprises a plurality of transfer heads and a first substrate carrying the plurality of transfer heads; an end surface of an end of the transfer head away from the first substrate has a first groove, and a photo-induced deformation structure is arranged in the first groove. The micro-LED is transferred by using the transfer device provided by the embodiments of the present application, the photo-induced deformation structure in the first groove is deformed and expanded by irradiating the transfer head with light, so that the photo-induced deformation structure extrudes the micro-LED to make it separate from the transfer head. In the transfer process, the transfer head does not need to be burned by laser, which can avoid the pollution of the burning residues to the micro-LED, and does not need high-temperature process conditions, which can avoid the damage of high temperature to the micro-LED. Moreover, the photo-induced deformation structure restores the deformation after removing the light, so that the transfer head can be reused, and the transfer efficiency of the massive transfer process can be improved.

Description

Technical Field

[0001] This invention belongs to the field of display technology, and more specifically relates to a transfer device and its manufacturing method, a method for transferring micro LEDs, and a display. Background Technology

[0002] Micro-LED (micro-LED, micro-light-emitting diode) displays are formed by thinning, miniaturizing, and arraying LED structures, transferring them onto a substrate in batches, and then encapsulating them. Compared with liquid crystal displays and organic light-emitting displays, micro-LED displays have advantages such as high brightness, high response speed, low power consumption, and long lifespan, thus becoming a research hotspot for next-generation display technologies.

[0003] Micro-LEDs are difficult to grow directly on glass substrates and require transfer technology to transfer the micro-LEDs grown on the source substrate onto the glass substrate. Because the number of micro-LEDs transferred at once is enormous, ranging from tens of thousands to hundreds of thousands, this process is called mass transfer. Given the tiny size of micro-LEDs (typically around 1–10 μm), high growth density, and massive transfer volume, ultra-high precision transfer equipment and transfer heads are generally required. This presents significant difficulties and challenges for the transfer equipment and technology, becoming one of the biggest obstacles to the mass production of micro-LED displays. Summary of the Invention

[0004] In view of this, the present invention provides a transfer device and its manufacturing method, a method for transferring micro-LEDs, and a display, to solve the technical problem of damage or contamination of micro-LEDs during the transfer of micro-LEDs in the prior art.

[0005] In a first aspect, embodiments of the present invention provide a transfer device, comprising: a plurality of transfer heads and a first substrate supporting the plurality of transfer heads; a first groove is provided on the end face of one end of the transfer head away from the first substrate, and a photodeformation structure is disposed within the first groove. The photodeformation structure has photodeformation characteristics; under irradiation with light of a specific wavelength and intensity, a photophysical or photochemical effect occurs within the photodeformation structure, converting light energy into mechanical energy and causing stretching deformation; when the light of the specific wavelength and intensity disappears, the photodeformation structure recovers its deformation.

[0006] The transfer device provided in this invention transfers micro-LEDs. First, a transfer head picks up the micro-LED from the source substrate. After moving the micro-LED to a position opposite to the receiving substrate, light irradiates the transfer head, causing the photo-deformation structure in the first groove to deform and expand. The expanded photo-deformation structure then compresses the micro-LED, causing it to detach from the transfer head and land on the corresponding position on the receiving substrate, thus achieving the transfer of the micro-LED. In this transfer process, laser burning of the transfer head is unnecessary, avoiding contamination of the micro-LED by burning residue, and high-temperature processing conditions are not required, preventing damage to the micro-LED from high temperatures. Furthermore, by irradiating the photo-deformation structure in the first groove of the transfer head with light, the deformed structure compresses the micro-LED, releasing it onto the receiving substrate. After the light is removed, the photo-deformation structure recovers its deformation, allowing the transfer head to be reused and improving the transfer efficiency of mass transfer processes. Additionally, this invention can selectively release specific micro-LEDs as needed, avoiding the transfer of defective devices to the receiving substrate and improving product yield.

[0007] In one embodiment, the photodeformation structure includes an elastic substrate and photodeformation particles dispersed in the elastic substrate. The photodeformation particles are sensitive to light of a specific wavelength; the elastic substrate has elastic recovery properties. When light of a specific wavelength and intensity irradiates the photodeformation structure, the photodeformation particles in the irradiated area convert light energy into mechanical energy, causing the elastic substrate to stretch and deform, thereby causing the entire photodeformation structure to stretch and deform. When the light disappears, the photodeformation structure recovers its deformation. This achieves a precise and rapid light-driven deformation process.

[0008] In one embodiment, the elastic substrate is a transparent elastic substrate. The elastic substrate has good light transmittance, ensuring minimal difference in light intensity across different parts of the photo-deformed structure during the transfer process, thus guaranteeing uniform deformation across all parts of the photo-deformed structure.

[0009] In the transfer device provided in this embodiment of the invention, the height of the transfer head is H and the depth of the first groove is h in the direction perpendicular to the first substrate; wherein, h ≤ H / 2. While ensuring that the photodeformation structure can protrude from the end face of the transfer head after deformation, the amount of material used to fabricate the photodeformation structure can be reduced.

[0010] In the transfer device provided in this embodiment of the invention, the distance between the surface of the photodeformation structure away from the first substrate and the first substrate is a first distance, and the distance between the end face of the photodeformation structure and the first substrate is a second distance, wherein the first distance is less than the second distance. This configuration ensures that during the transfer process, the micro-LED is picked up by the end face of the transfer head, and then released during the micro-LED release process by the photodeformation structure 30 deforming under light and squeezing the micro-LED.

[0011] Secondly, embodiments of the present invention also provide a method for manufacturing a transfer device, the method comprising:

[0012] A first substrate is provided, and a first material layer is coated on the first substrate;

[0013] A transfer template is provided, which has multiple second grooves and a boss at the bottom of the second groove, the height of the boss being less than the depth of the second groove.

[0014] The first material layer is aligned with the second groove, and the first substrate is controlled to be bonded to the transfer template so that the first material layer forms a transfer head; wherein the transfer head is fitted into the second groove, and the boss is fitted into the end face of the transfer head on the side away from the first substrate.

[0015] The transfer head is separated from the transfer template, and a first groove is formed on the end face of the transfer head on the side away from the first substrate;

[0016] A photodeformation structure is fabricated within the first groove.

[0017] The manufacturing method provided in the embodiments of the present invention utilizes a transfer template with a special pattern to manufacture a transfer device by transfer printing, which can be applied to the manufacture of any of the transfer devices provided in the embodiments of the present invention.

[0018] In some embodiments, the first material layer is positioned opposite the second groove, and the first substrate is controlled to adhere to the transfer template so that the first material layer forms a transfer head, including:

[0019] The first material layer is pre-baked to bring it into a semi-fluid state;

[0020] The first material layer, which is in a semi-fluid state, is positioned opposite the second groove;

[0021] The first substrate is controlled to adhere to the transfer template so that the first material layer flows into the second groove to form the transfer head precursor, and the boss is fitted into the end face of the transfer head precursor away from the first substrate.

[0022] The first substrate and the transfer template, which are in a bonding state, are baked to dry the transfer head precursor and form the transfer head.

[0023] In some embodiments, pre-baking the first material layer to make it in a semi-fluid state includes: pre-baking the first material layer at a temperature of 50°C to 160°C for a pre-baking time of 30 seconds to 6 minutes; baking the first substrate and the transfer template in the bonding state includes: baking the first substrate and the transfer template in the bonding state at a temperature of 50°C to 160°C for a baking time of 10 minutes to 200 minutes.

[0024] In some embodiments, controlling the first substrate to bond with the transfer template so that the first material layer flows into the second groove to form the transfer head precursor includes: controlling the first substrate and the transfer template to bond and remove bubbles under vacuum.

[0025] In some embodiments, a first substrate is provided, and after a first material layer is coated on the first substrate, the process further includes: performing a spin degassing treatment on the first material layer under vacuum. This step avoids air bubbles between the first material layer and the first substrate, which could affect the adhesion performance between the final transfer head and the first substrate. This step ensures the reliability of the transfer substrate formed by the first substrate and the transfer head.

[0026] In some embodiments, a transfer template is provided, comprising: providing a second substrate, coating a photoresist layer on the second substrate; exposing the photoresist layer using a photomask; and developing the exposed photoresist layer using a developer to form a second groove and a protrusion located at the bottom of the second groove. The pattern of the transfer template is fabricated using a photolithography-development process, which is simple and easy to manufacture. Specifically, the photomask can be designed according to the shape of the transfer head in the transfer apparatus to obtain a transfer template with a pattern having a structure opposite to that of the transfer head.

[0027] In some embodiments, fabricating a photodeformable structure within a first groove includes: mixing photodeformable particles and an elastic substrate, such that the photodeformable particles are dispersed in the elastic substrate to form a precursor solution; fabricating the precursor solution within the first groove using an inkjet printing process; and heating and curing the precursor solution within the first groove to form the photodeformable structure. This embodiment uses an inkjet printing process to fabricate the photodeformable structure. Inkjet printing is a mature and stable process with high fabrication precision.

[0028] Thirdly, embodiments of the present invention also provide a method for transferring micro-LEDs, wherein the micro-LEDs are transferred using the transfer device provided in any embodiment of the present invention, and the transfer method includes:

[0029] Multiple micro-LEDs are picked up from the source substrate using a transfer head, wherein one transfer head picks up one micro-LED;

[0030] The transfer head moves multiple micro-LEDs onto the receiving substrate and aligns the micro-LEDs with the receiving substrate.

[0031] A light source is used to irradiate the photo-deformed structure, causing it to expand and deform. The expanded and deformed photo-deformed structure then presses against the micro-LED contact, causing the micro-LED to separate from the transfer head. After separation, the micro-LED is released onto the corresponding position on the receiving substrate.

[0032] In one embodiment, a transfer head is used to pick up multiple micro-LEDs from a source substrate, including: controlling the end face of the transfer head away from the first substrate to contact the micro-LEDs, and using the adhesiveness of the end face to pick up multiple micro-LEDs from the source substrate.

[0033] In one embodiment, picking up multiple micro-LEDs from a source first substrate using a transfer head includes: applying an adhesive layer to an end face of the transfer head away from the first substrate; controlling the adhesive layer on the transfer head to contact the micro-LEDs; and picking up multiple micro-LEDs from the source substrate using the adhesive layer.

[0034] Fourthly, embodiments of the present invention also provide a display, the display including a substrate and a plurality of micro-LEDs located on the substrate, the micro-LEDs being transferred onto the substrate using a transfer method provided in any embodiment of the present invention.

[0035] The transfer device and its manufacturing method, the micro-LED transfer method, and the display provided by this invention have the following beneficial effects: When using the transfer device provided in this embodiment to transfer micro-LEDs, firstly, a transfer head picks up the micro-LED from the source substrate. After moving the micro-LED to a position relative to the receiving substrate, light irradiates the transfer head, causing the photo-induced deformation structure in the first groove to deform and expand. The expanded photo-induced deformation structure then compresses the micro-LED, causing it to detach from the transfer head. The micro-LED then falls onto the corresponding position on the receiving substrate, thus achieving the transfer of the micro-LED. In this transfer process, laser burning of the transfer head is unnecessary, avoiding contamination of the micro-LED by burning residue, and high-temperature processing conditions are not required, preventing damage to the micro-LED from high temperatures. Furthermore, by irradiating the photo-induced deformation structure in the first groove of the transfer head with light, the deformed structure compresses the micro-LED, releasing it onto the receiving substrate. After the light is removed, the photo-induced deformation structure recovers its deformation, allowing the transfer head to be reused and improving the transfer efficiency of mass transfer processes. In addition, the present invention can selectively release the corresponding micro LEDs according to the needs, avoiding the transfer of defective devices to the receiving substrate, thereby improving product yield. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a process flow diagram for the mass transfer of micro-LEDs in existing technologies;

[0038] Figure 2 This is a partial schematic diagram of a transfer device provided in an embodiment of the present invention;

[0039] Figure 3 for Figure 2 Schematic diagram of the cross section at the position of the midtangent AA′;

[0040] Figure 4 This is a partial schematic diagram of another transfer device provided in an embodiment of the present invention;

[0041] Figure 5 This is a partial schematic diagram of another transfer device provided in an embodiment of the present invention;

[0042] Figure 6 for Figure 5 Schematic diagram of the cross section at the position of the tangent line BB′;

[0043] Figure 7 This is a simplified schematic diagram of a micro LED to which the present invention can be applied;

[0044] Figure 8 This is a simplified schematic diagram of another micro LED to which the present invention can be applied;

[0045] Figure 9 A flowchart illustrating a method for transferring a micro LED according to an embodiment of the present invention;

[0046] Figure 10 This is another schematic diagram of step S103 in the transfer method;

[0047] Figure 11 This is a schematic diagram of another transfer device provided in an embodiment of the present invention;

[0048] Figure 12 This is a schematic diagram of the photodeformation structure in an embodiment of the present invention;

[0049] Figure 13 This is a schematic diagram illustrating the photoinduced deformation principle of azobenzene materials.

[0050] Figure 14 A flowchart of another transfer method provided in an embodiment of the present invention;

[0051] Figure 15 A flowchart of another transfer method provided in an embodiment of the present invention;

[0052] Figure 16 A schematic diagram of a display provided in an embodiment of the present invention;

[0053] Figure 17 This is a schematic diagram of another display provided in an embodiment of the present invention;

[0054] Figure 18 A flowchart illustrating a method for manufacturing a transfer device according to an embodiment of the present invention;

[0055] Figure 19 This is a partial top view of a transfer template;

[0056] Figure 20 A flowchart illustrating another method for manufacturing the transfer device provided in an embodiment of the present invention;

[0057] Figure 21 A flowchart illustrating another method for manufacturing the transfer device provided in an embodiment of the present invention;

[0058] Figure 22 A flowchart illustrating another method for manufacturing the transfer device provided in an embodiment of the present invention. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0061] Figure 1 This is a process flow diagram for the mass transfer of micro-LEDs in existing technologies. Figure 1As shown, multiple regularly arranged microLEDs 01 are grown on the source substrate 00. Regularly arranged transfer heads 021 are disposed on the transfer substrate 02. The transfer substrate 02 is brought close to the source substrate 00, and the transfer heads 021 remove the microLEDs at corresponding positions. Then, the transfer substrate 02 approaches the receiving substrate 03, releasing the microLEDs 021 from the transfer heads 021 onto the receiving substrate 03. The microLEDs 021 then contact the contact electrodes 031 on the receiving substrate 03, completing the transfer of the microLEDs.

[0062] In a prior art, a thin film material is present on the surface of each transfer head 021 of the transfer substrate 02. In the transfer process, the adhesive properties of the thin film material are used to adhere the micro-LED 01 to the source substrate. After aligning the micro-LED 01 with the receiving substrate 03, the thin film material on the transfer head 021 is burned off by a laser to release the micro-LED 01 onto the receiving substrate 03. In this process, the residue left after laser burning of the thin film material on the transfer head 021 easily contaminates the surface of the micro-LED. Furthermore, because the thin film material on the transfer head 021 cannot be reused, the preparation time for mass transfer processes is long, affecting mass production.

[0063] In another prior art, a layer of low-melting-point metal (such as indium or tin) is present on the surface of each transfer head 021 of the transfer substrate 02. The metal is melted by heating, causing it to metal-bond with the micro-LED. After cooling, the micro-LED 01 is bonded to the transfer head 021, and then the transfer head 021 is used to bond the micro-LED to the source substrate 00. After aligning the micro-LED 01 with the receiving substrate 03, the metal is melted again by heating, causing the micro-LED 01 to detach from the transfer head 021 and transfer to the receiving substrate 03. This process requires heating to the melting point of the metal, resulting in a relatively high process temperature. The high temperature during the picking and releasing of the micro-LED 01 can cause some damage to the micro-LED device.

[0064] To address the problems of existing technologies, this invention provides a transfer device and a method for transferring micro-LEDs. The transfer head has a groove on its end face, within which a photo-deformation structure is disposed. This photo-deformation structure deforms upon exposure to light and returns to its original shape after the light is removed. In the transfer process, the transfer head picks up a micro-LED from the source substrate. When the micro-LED is moved to a corresponding position on the receiving substrate, light irradiates the transfer head, causing the photo-deformation structure within the groove to deform and expand. This expanded structure then compresses the micro-LED, causing it to detach from the transfer head and fall onto the corresponding position on the receiving substrate, thus achieving the transfer of the micro-LED. The transfer method provided by this invention eliminates the need for laser ablation of the transfer head, avoiding contamination of the micro-LED by ablation residues. It also eliminates the need for high-temperature processing conditions, preventing damage to the micro-LED from high temperatures. Furthermore, by irradiating the photo-deformation structure within the groove on the transfer head with light, the deformed structure compresses the micro-LED, releasing it onto the receiving substrate, enabling selective release of the micro-LED. In addition, the transfer head in the transfer device can be reused, which can improve the transfer efficiency of mass transfer processes.

[0065] Figure 2 This is a partial schematic diagram of a transfer device provided in an embodiment of the present invention. Figure 3 for Figure 2 A schematic diagram of the cross section at the location of the tangent AA′.

[0066] Combination Figure 2 and Figure 3 The transfer device 100 includes a first substrate 10 and a plurality of transfer heads 20. The first substrate 10 supports the plurality of transfer heads 20, which are located on one side of the first substrate 10. The plurality of transfer heads 20 and the first substrate 10 supporting them together constitute the transfer substrate in the transfer device 100. A first groove 22 is provided on the end face 21 of the transfer head 20 away from the first substrate 10, and a photodeformation structure 30 is disposed within the first groove 22. The photodeformation structure 30 has photodeformation characteristics; under irradiation with light of a specific wavelength and intensity, a photophysical or photochemical effect occurs inside the photodeformation structure 30, converting light energy into mechanical energy and causing stretching deformation; when the light of the specific wavelength and intensity disappears, the photodeformation structure 30 recovers its deformation. The deformation process of the photodeformation structure 30 is carried out under light-driven conditions, exhibiting recoverable and repeatable driving characteristics.

[0067] Figure 2 In this embodiment, the transfer head 20 is schematically shown in a cylindrical shape, consisting of... Figure 2It can be seen that the outer contour of the end face 21 of the transfer head 20, which is away from the first substrate 10, is circular. In this embodiment of the invention, the shape of the transfer head 20 is not limited; in some embodiments, the transfer head 20 may also be a polygonal prism.

[0068] In one embodiment, Figure 4 This is a partial schematic diagram of another transfer device provided in an embodiment of the present invention. Figure 4 This is a top-down view diagram, by Figure 4 It can be seen that the outer contour shape of the end face 21 of the transfer head 20 away from the first substrate 10 is quadrilateral, and in this embodiment, the shape of the transfer head 20 is a quadrangular prism.

[0069] In addition, the shape of the first groove 22 is not limited in this embodiment of the invention. Figure 2 and Figure 4 In the embodiments, the photodeformation structure 30 is shown surrounded by the sidewall of the first groove 22.

[0070] In another embodiment, Figure 5 This is a partial schematic diagram of another transfer device provided in an embodiment of the present invention. Figure 6 for Figure 5 A schematic diagram of the cross-section at the location of the midtangent BB′. (Combined with...) Figure 5 and Figure 6 As can be seen, in this embodiment, the first groove 22 extends through the end of the transfer head 20 in its extending direction.

[0071] The transfer device 100 provided in this embodiment of the invention can be used for mass transfer of micro LEDs. The micro LEDs can be lateral or vertical light-emitting diodes.

[0072] Figure 7 This is a simplified schematic diagram of a micro LED to which the present invention can be applied, such as... Figure 7 As shown, a micro-LED comprises a P-electrode, a P-type semiconductor, a multi-period quantum well active layer, an N-type semiconductor, and an N-electrode. A micro-LED is a PN junction diode constructed from a direct bandgap semiconductor material. The P-type and N-type semiconductors are fabricated on the same semiconductor substrate, forming a space charge region at their interface, known as a PN junction. Holes dominate in the P-type semiconductor (Positive, hole-dominant semiconductor), while electrons dominate in the N-type semiconductor (Negative, electron-dominant semiconductor). When a forward bias voltage is applied to the P and N electrodes of the micro-LED, causing current to flow, electrons and holes recombine within the multi-period quantum well active layer, releasing energy as light emission, emitting a single color of light. Figure 7In this embodiment, the P electrode and N electrode are located on the same side, so the micro LED 40 in this embodiment is a lateral micro light-emitting diode.

[0073] Figure 8 This is a simplified schematic diagram of another micro LED to which the present invention can be applied, as shown below. Figure 8 As shown, the P electrode and N electrode are located on both sides of the micro LED, and the micro LED illustrated in this embodiment is a vertical micro LED.

[0074] In one embodiment, Figure 9 A flowchart of a method for transferring a micro LED provided in an embodiment of the present invention is shown below. Figure 9 As shown, the transfer methods include:

[0075] Step S101: Use the transfer head 20 to pick up multiple micro LEDs 01 from the source substrate 00, wherein one transfer head 20 picks up one micro LED 01. Figure 9 The micro-LED01 is illustrated using a horizontally oriented micro-light-emitting diode. Figure 9 The diagram also illustrates the P electrode 011 and N electrode 012 of the micro LED 01.

[0076] Step S102: The transfer head 20 moves multiple micro-LEDs 01 onto the receiving substrate 200 and aligns the micro-LEDs 01 with the receiving substrate 200. For example... Figure 9 As illustrated, the receiving substrate 200 includes a substrate 210 and a thin-film transistor layer 220 located on the substrate 210. The thin-film transistor layer 220 includes a plurality of thin-film transistors, which function as devices to drive micro-LEDs to emit light.

[0077] When the micro LED 01 is a lateral micro light-emitting diode, a first contact electrode 201 corresponding to the P electrode 011 of the micro LED 01 and a second contact electrode 202 corresponding to the N electrode 012 are respectively provided on the corresponding position of the receiving substrate 200.

[0078] It can be understood that the transfer method provided in the embodiments of the present invention is used for... Figure 8 In the embodiment, when the vertical micro-LED is transferred, a contact electrode corresponding to the P-electrode of the vertical micro-LED is provided on the receiving substrate 200. Then, in step S102, the micro-LED is moved onto the receiving substrate 200, aligning the P-electrode of the micro-LED with the contact electrode.

[0079] Step S103: The photo-deformed structure 30 is irradiated by the light source 300 to cause the photo-deformed structure 30 to expand and deform. After expansion and deformation, the photo-deformed structure 30 squeezes the micro-LED 01 to separate the micro-LED 01 from the transfer head 20. After separation, the micro-LED 01 is released at the corresponding position on the receiving substrate 200.

[0080] In this embodiment of the invention, the first substrate 10 in the transfer device 100 is a light-transmitting substrate, optionally a glass substrate. This ensures the light transmittance of the first substrate 10. In the transfer process, the light emitted by the light source 300 passes through the first substrate 10 and then irradiates the photodeformation structure 30 at one end of the transfer head 20, causing the photodeformation structure 30 to deform.

[0081] After step S103, the light source 300 is removed, and the photodeformation structure 30 in the transfer head 20 recovers its original shape, that is, after recovery of deformation, it is located in the first groove. The transfer head 20 provided by the present invention can be reused in the transfer process.

[0082] Optional, Figure 10 Another schematic diagram of step S103 in the transfer method is shown below. Figure 10 As shown, the light source can be controlled to selectively illuminate the corresponding transfer head 20, causing the photodeformation structure 30 in the transfer head 20 to deform and compress the corresponding micro-LED 01. This allows for the selective release of the corresponding micro-LED 01, preventing defective devices from being transferred to the receiving substrate, thus improving product yield.

[0083] The transfer device provided in this invention transfers micro-LEDs. First, a transfer head picks up the micro-LED from the source substrate. After moving the micro-LED to a position opposite to the receiving substrate, light irradiates the transfer head, causing the photo-deformation structure in the first groove to deform and expand. The expanded photo-deformation structure then compresses the micro-LED, causing it to detach from the transfer head and land on the corresponding position on the receiving substrate, thus achieving the transfer of the micro-LED. In this transfer process, laser burning of the transfer head is unnecessary, avoiding contamination of the micro-LED by burning residue, and high-temperature processing conditions are not required, preventing damage to the micro-LED from high temperatures. Furthermore, by irradiating the photo-deformation structure in the first groove of the transfer head with light, the deformed structure compresses the micro-LED, releasing it onto the receiving substrate. After the light is removed, the photo-deformation structure recovers its deformation, allowing the transfer head to be reused and improving the transfer efficiency of mass transfer processes. Additionally, this invention can selectively release specific micro-LEDs as needed, avoiding the transfer of defective devices to the receiving substrate and improving product yield.

[0084] In one embodiment, Figure 11 This is a schematic diagram of another transfer device provided in an embodiment of the present invention. Figure 11 As shown, the transfer apparatus 100 includes a control unit 400, a light source generator 500, and a transfer substrate 600. The transfer substrate 600 includes a plurality of transfer heads 20 and a first substrate 10 supporting the transfer heads 20. A first groove is formed on the end face of each transfer head 20 away from the first substrate 10, and a photodeformation structure 30 is disposed within the first groove. The light source generator 500 and the transfer substrate 600 are respectively connected to the control unit 400. In the transfer process, the light source generator 500 is used to provide a light source 300 after being turned on.

[0085] The control unit 400 is used to control the working process of the transfer substrate 600. Specifically, in step S101, the control unit 400 controls the transfer substrate 600 to pick up multiple micro LEDs 01 from the source substrate 00; in step S102, the control unit 400 controls the transfer substrate 600 to move the multiple micro LEDs 01 and controls the micro LEDs to align with the receiving substrate 200.

[0086] The control unit 400 is also used to control the on and off states of the light source generator 500. Specifically, in step S103, the control unit 400 controls the light source generator 500 to turn on, so that the light source irradiates the photodeformation structure 30, causing the photodeformation structure 30 to expand and deform. After step S103, the control unit 400 controls the light source generator 500 to turn off, and the photodeformation structure 30 in the transfer head 20 returns to its original shape.

[0087] Furthermore, the control unit 400 is also used to control the direction of travel of the light source generator 500. Optionally, after the light source generator 500 is turned on, it provides a linear light source or a planar light source. By controlling the direction of travel of the light source generator 500 through the control unit 400, the light source can be directed to the transfer head 20 at the corresponding position, thereby enabling selective release of the micro LEDs.

[0088] Furthermore, the type of the light source generator 500 is not limited in this embodiment of the invention. The light source 300 provided by the light source generator 500 after being turned on matches the photodeformation structure 30 in the transfer head 20. In one embodiment, the photodeformation structure 30 deforms under ultraviolet light irradiation, then the light source generator 500 is an ultraviolet light generator. In one embodiment, the photodeformation structure 30 deforms under infrared light irradiation, then the light source generator 500 is an infrared light generator. In another embodiment, the photodeformation structure 30 deforms under visible light irradiation, then the light source generator 500 is a visible light generator.

[0089] In one embodiment, Figure 12This is a schematic diagram of the photodeformation structure in an embodiment of the present invention, such as... Figure 12 As shown, the photodeformation structure 30 includes an elastic substrate 31 and photodeformation particles 32 dispersed in the elastic substrate 31. The photodeformation particles 32 are sensitive to light of a specific wavelength; the elastic substrate 31 has elastic recovery properties. When light of a specific wavelength and intensity irradiates the photodeformation structure 30, the photodeformation particles 32 in the irradiated area convert light energy into mechanical energy, causing the elastic substrate 31 to undergo expansion and contraction deformation, thereby causing the photodeformation structure 30 as a whole to undergo expansion and contraction deformation; when the light disappears, the photodeformation structure 30 recovers its deformation. This achieves a precise and rapid light-driven deformation process, and the deformation process of the photodeformation structure 30 has the characteristics of recoverability and repeatable driving.

[0090] In one embodiment, the photodeformable particles 32 comprise a photodeformable polymer, such as an azophenyl polymer. Figure 13 This is a diagram illustrating the principle of photoinduced deformation of azobenzene materials, such as... Figure 13 As shown, azobenzene exists in two conformations: cis and trans. The trans conformation is more stable, but it transforms into the cis conformation under ultraviolet light. The trans conformation of azobenzene has a molecular length of approximately 0.9 nm, while the cis conformation has a length of approximately 0.55 nm. When a polymer molecular chain contains multiple azobenzene structures, numerous microscopic transformations typically lead to macroscopic mass transfer in the azobenzene polymer material, i.e., macroscopic material deformation. Azobenzene polymers exhibit high photodeformation efficiency and are less prone to material fatigue.

[0091] In one embodiment, the elastic substrate 31 is a transparent elastic substrate. In this embodiment, the elastic substrate 31 has good light transmittance, and when light irradiates the photodeformation structure 30 during the transfer process, it can ensure that the difference in light intensity among different parts of the photodeformation structure 30 is small, thus ensuring uniform deformation of different parts of the photodeformation structure 30.

[0092] Continue to refer to Figure 3 As shown, in the direction e perpendicular to the first substrate 10, the height of the transfer head 20 is H, and the depth of the first groove 22 is h; where h ≤ H / 2. In this embodiment of the invention, the first groove 22 is used to accommodate the photodeformation structure 30. The photodeformation structure 30 can deform after being illuminated. It can be understood that the deformation of the photodeformation structure 30 is related to its volume and the volume ratio of the dispersed photodeformation particles 32 inside it. By setting h ≤ H / 2, while ensuring that the photodeformation structure 30 can protrude from the end face 21 of the transfer head 20 after deformation, the amount of material used to manufacture the photodeformation structure 30 can be reduced.

[0093] like Figure 3As shown in the figure, the distance between the surface of the photo-induced deformation structure 30 on the side away from the first substrate 10 and the first substrate 10 is d, and the distance between the end face 21 of the transfer head 20 on the side away from the first substrate 10 and the first substrate 10 is substantially equal to the height H of the transfer head 20. In the embodiment of the present invention, d < H. That is to say, the photo-induced deformation structure 30 is located inside the first groove 22, and a step difference is formed between the surface of the photo-induced deformation structure 30 and the end face 21 of the transfer head 20. With such a setting, it can be ensured that in the transfer process, the micro-LEDs are picked up by relying on the end face 21 of the transfer head 20, and then during the release process of the micro-LEDs, the photo-induced deformation structure 30 is deformed by light and squeezes the micro-LEDs to release the micro-LEDs.

[0094] In one embodiment, the transfer head 20 is made of a material with viscosity. Optionally, the material for making the transfer head 20 includes polydimethylsiloxane (PDMS). The viscosity of the PDMS material changes little with temperature, which can ensure the transfer yield. The transfer method for transferring micro-LEDs using the transfer device provided in the embodiment is as Figure 14 shown. Figure 14 Another flowchart of the transfer method provided by the embodiment of the present invention, the transfer method includes:

[0095] Step S201: Control the end face 21 of the transfer head 20 on the side away from the first substrate 10 to contact the micro-LEDs, and pick up a plurality of micro-LEDs from the source substrate by using the viscosity of the end face 21.

[0096] Step S202: The transfer head 20 drives the plurality of micro-LEDs to move above the receiving substrate, and aligns the micro-LEDs with the receiving substrate. This step can refer to the Figure 9 drawings and related descriptions of step S102 in the above

[0097] Step S203: Use a light source to irradiate the photo-induced deformation structure 30 to make the photo-induced deformation structure 30 expand and deform. After the expansion and deformation, the photo-induced deformation structure 30 squeezes the micro-LEDs to separate the micro-LEDs from the transfer head 20. After the micro-LEDs are separated from the transfer head 20, they are released at the corresponding positions on the receiving substrate. This step can refer to the Figure 9 drawings and related descriptions of step S103 in the above

[0098] The transfer method provided by this embodiment uses the viscosity of the transfer head 20 itself to pick up the micro-LEDs from the source substrate.

[0099] In another embodiment, Figure 15 Another flowchart of the transfer method provided by the embodiment of the present invention, as Figure 15 shown, the transfer method includes:

[0100] Step S301: Apply an adhesive layer 23 to the end face of the transfer head 20 on the side away from the first substrate 10. The adhesive layer 23 can be made of thermoplastic olefin polymers (polyvinyl acetate, polyvinyl alcohol, chlorinated polyethylene, polyisobutylene, etc.), polyester, polyether, polyamide, polyacrylate, etc.; or it can be thermosetting epoxy resin, phenolic resin; or it can be rubber-based styrene-butadiene rubber, butyl rubber, phenolic-nitrile rubber, phenolic-chloroprene rubber.

[0101] Step S302: Control the adhesive layer 23 on the transfer head 20 to contact the micro LED 01, and use the adhesive layer 23 to pick up multiple micro LEDs 01 from the source substrate 00.

[0102] Step S303: The transfer head 20 moves multiple micro-LEDs 01 onto the receiving substrate 200 and aligns the micro-LEDs 01 with the receiving substrate 200. In this embodiment, the relevant descriptions of the micro-LEDs 01 and the receiving substrate 200 can be found above. Figure 9 The examples are explained in detail here and will not be repeated.

[0103] Step S304: The photo-deformed structure 30 is irradiated by the light source 300 to cause the photo-deformed structure 30 to expand and deform. After expansion and deformation, the photo-deformed structure 30 squeezes the micro-LED 01 to separate the micro-LED 01 from the transfer head 20. After separation, the micro-LED 01 is released at the corresponding position on the receiving substrate 200.

[0104] The transfer method provided in this embodiment uses the adhesiveness of the adhesive layer 23 coated on the transfer head 20 to pick up the micro LED from the source substrate.

[0105] This invention also provides a display. Figure 16 A schematic diagram of a display provided in an embodiment of the present invention, such as... Figure 16 As shown, the display 700 includes a substrate 710 and a plurality of micro-LEDs 720 located on the substrate 710. The micro-LEDs 720 are transferred onto the substrate 710 using any of the transfer methods provided in this embodiment of the invention. The substrate 710 is the receiving substrate 200 in the transfer process. The substrate 710 includes a substrate 711 and a thin-film transistor layer 712, in which a plurality of thin-film transistors are disposed. The thin-film transistor layer 712 is used to control the light emission of the micro-LEDs 720.

[0106] The display also includes an encapsulation layer 730 that covers the micro-LED 720 and protects the micro-LED 720. Optionally, the encapsulation layer 730 may include an inorganic encapsulation layer and an organic encapsulation layer.

[0107] When the micro LED 720 is a lateral micro light-emitting diode, after transferring the micro LED 720 to the substrate 710, the encapsulation layer 730 is directly fabricated on the micro LED 720.

[0108] When the micro LED 720 is a vertical micro light-emitting diode, after transferring the micro LED 720 to the substrate 710, a common electrode layer is first fabricated, and then an encapsulation layer 730 is fabricated on the common electrode layer.

[0109] In one embodiment, substrate 711 is a rigid substrate, such as a glass substrate. In another embodiment, substrate 711 is a flexible substrate, such as a polyimide substrate.

[0110] In another embodiment, Figure 17 This is another schematic diagram of a display provided in an embodiment of the present invention, such as... Figure 17 As shown, the display 700 also includes a driver chip 740 and a flexible circuit board 750, both of which are bonded to one end of the substrate 710. Driven by the driver chip 740 and the flexible circuit board 750, the light-emitting state of the micro-LED 720 is controlled by the thin-film transistors in the thin-film transistor layer 712.

[0111] The present invention also provides a method for manufacturing a transfer device, used to manufacture the transfer device provided in the above embodiments of the present invention. Figure 18 A flowchart illustrating a method for manufacturing a transfer device according to an embodiment of the present invention is shown below. Figure 18 As shown, the manufacturing method includes:

[0112] Step S401: Provide a first substrate 10, and coat a first material layer 40 on the first substrate 10;

[0113] Step S402: Provide a transfer template 50, the transfer template 50 having a plurality of second grooves 51, and a boss 52 at the bottom of the second grooves 51. Figure 18 As shown, the height d1 of the boss 52 is less than the depth h1 of the second groove 51. The transfer template 50 also includes a second substrate 53.

[0114] Figure 19 This is a partial top view of a transfer template, combined with... Figure 19 Understanding the shape of the transfer template 50. Figure 19In this diagram, the shape of the second groove 51 is only shown schematically. Specifically, the transfer template 50 is designed according to the required shape of the transfer head 20 in the transfer device. The second groove 51 and the boss 52 on the transfer template 50 are opposite structures to the transfer head 20 and the first groove 21 on the transfer head 20 in the transfer device manufactured using this embodiment of the invention. That is, after the transfer head 20 and the transfer template 50 are fitted together, the transfer head 20 and the second groove 51 can be interlocked, and the first groove 21 at the end of the transfer head 20 and the boss 52 inside the second groove 51 can be interlocked.

[0115] Step S403: The first material layer 40 is aligned with the second groove 51, and the first substrate 10 is bonded to the transfer template 50 so that the first material layer 40 forms a transfer head 20; wherein the transfer head 20 is fitted into the second groove 51, and the boss 52 is fitted into the end face of the transfer head 20 on the side away from the first substrate 10.

[0116] Step S404: Separate the transfer head 20 from the transfer template 50, and form a first groove 22 on the end face 21 of the transfer head 20 on the side away from the first substrate 10;

[0117] Step S405: Fabricate a photodeformation structure 30 within the first groove 22.

[0118] After step S405, the transfer head 20 and the first substrate 10 supporting the transfer head 20 together form the transfer substrate in the transfer device. In this embodiment, the order of steps S401 and S402 can be interchanged. Using the manufacturing method provided in this embodiment of the invention, a transfer substrate is manufactured by transfer using a transfer template with a special pattern. The transfer substrate includes a first substrate 10 and a plurality of transfer heads 20 located on one side of the first substrate 10. A first groove 22 is provided on the end face 21 of the transfer head 20 away from the first substrate 10, and a photodeformation structure 30 is formed in the first groove 22.

[0119] Furthermore, Figure 20 A flowchart illustrating another method for manufacturing the transfer device provided in an embodiment of the present invention is shown below. Figure 20 As shown, step S403: The first material layer 40 is aligned with the second groove 51, and the first substrate 10 is bonded to the transfer template 50, so that the first material layer 40 forms the transfer head 20, including:

[0120] Step S4031: Pre-bake the first material layer 40 to bring it into a semi-fluid state. The semi-fluid state is a state between solid and liquid, in which the first material layer 40 still retains a certain degree of fluidity.

[0121] Pre-baking the first material layer 40 effectively fixes it in place, preventing it from overflowing due to excessive fluidity and improving the uniformity of its thickness. Furthermore, pre-baking enhances the adhesion between the first material layer 40 and the first substrate 10, facilitating the separation of the transfer head 20 from the transfer template 50 in subsequent processes.

[0122] Optionally, the first material layer 40 is pre-baked at a temperature of 50℃ to 160℃ for 30 seconds to 6 minutes. By controlling the pre-baking time and temperature, the first material layer 40 is ensured to be in a semi-fluid state after pre-baking.

[0123] Step S4032: Position the first material layer 40, which is in a semi-fluid state, opposite the second groove 51.

[0124] Step S4033: Control the first substrate 10 to adhere to the transfer template 50 so that the first material layer 40 flows into the second groove 51 to form the transfer head precursor, and the boss 52 is fitted into the end face of the transfer head precursor away from the first substrate 10.

[0125] In this step, after the first substrate 10 is bonded to the transfer template 50, the first material layer 40, which is in a semi-fluid state, can flow into the space inside the second groove 51 of the transfer template 50 by means of its fluidity, thereby transferring the pattern of the second groove 51 and the boss 52 on the transfer template 50 onto the first material layer 40 to form a transfer head precursor. At this time, the shape of the transfer head precursor is the same as the shape of the expected transfer head.

[0126] Optionally, in step S403, the first substrate 10 and the transfer template 50 are bonded and debubbled under vacuum conditions, wherein the bonding and debubbling time is maintained for more than 50 seconds, and the process temperature is controlled to be 0 to 50°C.

[0127] Step S4034: Bake the first substrate 10 and the transfer template 50 in the bonding state to dry the transfer head precursor and form the transfer head 20.

[0128] Optionally, the first substrate 10 and the transfer template 50 in the bonding state are baked at a temperature of 50℃ to 160℃ for 10 min to 200 min.

[0129] In some embodiments, step S401 provides a first substrate 10. After coating the first material layer 40 onto the first substrate 10, the fabrication method further includes: performing a spin degassing treatment on the first material layer 40 under vacuum. This step avoids air bubbles between the first material layer 40 and the first substrate 10, which could affect the adhesion performance between the finally fabricated transfer head 20 and the first substrate 10. This step ensures the reliability of the transfer substrate formed by the first substrate 10 and the transfer head 20.

[0130] In one implementation, Figure 21 A flowchart illustrating another method for manufacturing the transfer device provided in an embodiment of the present invention is shown below. Figure 21 As shown, step S402 provides a transfer template 50, including:

[0131] S4021: A second substrate 53 is provided, and a photoresist layer is coated on the second substrate 53; wherein the thickness of the photoresist layer is set according to the height of the transfer head to be fabricated. Optionally, the thickness of the photoresist layer is 2 to 20 μm.

[0132] S4022: Exposure of photoresist layer 60 using photomask 70;

[0133] S4023: The exposed photoresist layer 60 is developed using a developer to form a second groove 51 and a boss 52 located at the bottom of the second groove 51.

[0134] The pattern for the transfer template is created using a photolithography-development process, which is simple and easy to manufacture. Specifically, the photomask can be designed according to the shape of the transfer head in the transfer device to produce a transfer template with a pattern that is the opposite of the structure of the transfer head.

[0135] In one implementation, Figure 22 A flowchart illustrating another method for manufacturing the transfer device provided in an embodiment of the present invention is shown below. Figure 22 As shown, step S405 involves fabricating a photodeformation structure within the first groove, including:

[0136] Step S4051: Mix the photodeformation particles 32 and the elastic substrate 31 so that the photodeformation particles 32 are dispersed in the elastic substrate 31 to form a precursor solution;

[0137] Step S4052: The precursor solution is fabricated in the first groove 22 using inkjet printing technology;

[0138] Step S4053: The precursor solution in the first groove 22 is heated and cured to form a photodeformed structure 30. Optionally, the precursor solution is cured to form the photodeformed structure 30 after being treated at 110°C for 20 to 40 minutes.

[0139] This implementation method uses inkjet printing technology to fabricate the photodeformation structure 30. Inkjet printing technology is mature, stable, and has high fabrication precision.

[0140] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0141] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A transfer device, characterized in that, The transfer device includes: Multiple transfer heads and a first substrate supporting the multiple transfer heads; the transfer heads are made of an adhesive material; The transfer head has a first groove on the end face away from the first substrate, and a photodeformation structure is provided in the first groove; The distance between the surface of the photodeformation structure away from the first substrate and the first substrate is a first distance, and the distance between the end face and the first substrate is a second distance, wherein the first distance is less than the second distance; The end face of the transfer head that forms a step with the surface of the photo-deformed structure is adhesive.

2. The transfer device according to claim 1, characterized in that, The photodeformation structure includes an elastic substrate and photodeformation particles dispersed in the elastic substrate.

3. The transfer device according to claim 2, characterized in that, The elastic substrate is a transparent elastic substrate.

4. The transfer device according to claim 1, characterized in that, In the direction perpendicular to the first substrate, the height of the transfer head is H, and the depth of the first groove is h; wherein, h≤H / 2.

5. A method for manufacturing a transfer device, characterized in that, The manufacturing method includes: A first substrate is provided, and a first material layer is coated on the first substrate; A transfer template is provided, comprising: providing a second substrate, coating a photoresist layer on the second substrate; exposing the photoresist layer using a photomask; developing the exposed photoresist layer using a developing solution to form a second groove and a boss located at the bottom of the second groove; the height of the boss is less than the depth of the second groove; the transfer template has a plurality of second grooves, and adjacent second grooves are not interconnected. The first material layer is aligned with the second groove, and the first substrate is controlled to adhere to the transfer template so that the first material layer forms a transfer head; wherein the transfer head is fitted into the second groove, and the boss is fitted into the end face of the transfer head on the side away from the first substrate; The transfer head is separated from the transfer template, and a first groove is formed on the end face of the transfer head on the side away from the first substrate. Fabricating a photodeformation structure within the first groove includes: fabricating a precursor solution within the first groove using an inkjet printing process; heating and curing the precursor solution within the first groove to form the photodeformation structure; wherein the distance between the surface of the photodeformation structure away from the first substrate and the first substrate is a first distance, the distance between the end face and the first substrate is a second distance, and the first distance is less than the second distance.

6. The manufacturing method according to claim 5, characterized in that, The method involves aligning the first material layer with the second groove and controlling the first substrate to adhere to the transfer template, thereby forming a transfer head from the first material layer. The first material layer is pre-baked to bring it into a semi-fluid state. The first material layer, which is in a semi-fluid state, is positioned opposite the second groove; The first substrate is controlled to adhere to the transfer template so that the first material layer flows into the second groove to form the transfer head precursor, and the boss is fitted into the end face of the transfer head precursor away from the first substrate. The first substrate and the transfer template, which are in a bonded state, are baked to dry the transfer head precursor and form the transfer head.

7. The manufacturing method according to claim 6, characterized in that, Pre-baking the first material layer to make it in a semi-fluid state includes: pre-baking the first material layer at a temperature of 50°C to 160°C for a pre-baking time of 30 seconds to 6 minutes. Baking the first substrate and the transfer template in the bonding state includes baking the first substrate and the transfer template in the bonding state at a temperature of 50°C to 160°C for a baking time of 10 min to 200 min.

8. The manufacturing method according to claim 6, characterized in that, Controlling the first substrate to adhere to the transfer template so that the first material layer flows into the second groove to form the transfer head precursor, includes: The first substrate and the transfer template are bonded and debubbled under vacuum.

9. The manufacturing method according to claim 5, characterized in that, The method includes providing a first substrate, coating a first material layer on the first substrate, and then further comprising performing a spin degassing treatment on the first material layer under vacuum.

10. The manufacturing method according to claim 5, characterized in that, Fabricating a photodeformable structure within the first groove includes: Photodeformable particles are mixed with an elastic substrate, thereby dispersing the photodeformable particles in the elastic substrate to form the precursor solution.

11. A method for transferring micro-LEDs, comprising using the transfer apparatus as described in any one of claims 1 to 4 to transfer the micro-LEDs, characterized in that, The transfer method includes: Multiple micro-LEDs are picked up from the source substrate using the transfer head, with one transfer head picking up one micro-LED; wherein, the end face of the transfer head away from the first substrate is controlled to contact the micro-LED, and the adhesiveness of the end face is used to pick up multiple micro-LEDs from the source substrate. The transfer head moves multiple micro-LEDs onto the receiving substrate and aligns the micro-LEDs with the receiving substrate. The photo-deformed structure is irradiated with a light source to cause it to expand and deform. After expansion and deformation, the photo-deformed structure comes into contact with and presses against the micro-LED, causing the micro-LED to separate from the transfer head. After separation, the micro-LED is released onto the corresponding position on the receiving substrate.

12. A display, characterized in that, The device includes a substrate and a plurality of microLEDs located on the substrate, the microLEDs being transferred onto the substrate using the transfer method of claim 11.

13. A display, characterized in that, It includes a substrate and a plurality of microLEDs located on the substrate, the microLEDs being transferred onto the substrate using the transfer device according to any one of claims 1 to 4.

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