Transfer device and transfer method for light-emitting devices

Abstract

This application relates to a transfer device and method for light-emitting devices. The transfer device includes a transfer substrate and a plurality of pickup units arrayed on the transfer substrate. Each pickup unit includes an electrical control and an elastic element covering the outer periphery of the electrical control. The electrical control is electrically connected to the transfer substrate. The end of the elastic element away from the transfer substrate has a concave surface. When the concave surface contacts the surface of the light-emitting device, it generates a negative pressure to attract the light-emitting device. When energized, the electrical control can extend, deforming the concave surface into a convex surface and releasing the light-emitting device. This achieves precise attraction and release of multiple light-emitting devices, simplifies the mass transfer process of light-emitting devices, and improves transfer efficiency.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to a transfer device and method for a light-emitting device. Background Technology

[0002] With the development of display technology, display devices based on miniature light-emitting devices (MiniLED or MicroLED) have begun to be used. These devices consist of only one display substrate containing tens of thousands of miniature light-emitting devices. Therefore, how to efficiently and accurately transfer these miniature light-emitting devices onto the target substrate has become a major challenge. Summary of the Invention

[0003] This application aims to provide a transfer device and method for light-emitting devices, which can achieve precise adsorption and release of multiple light-emitting devices, simplify the mass transfer process of light-emitting devices, and improve transfer efficiency.

[0004] In a first aspect, embodiments of this application propose a transfer device for a light-emitting device, including a transfer substrate and a plurality of pickup units arrayed on the transfer substrate. Each pickup unit includes an electrical control and an elastic member covering the outer periphery of the electrical control. The electrical control is electrically connected to the transfer substrate. One end of the elastic member away from the transfer substrate has a concave surface. When the concave surface contacts the surface of the light-emitting device, it can form a negative pressure to adsorb the light-emitting device. When energized, the electrical control can extend to deform the concave surface into a convex surface and release the light-emitting device.

[0005] In one possible implementation, the transfer substrate includes a substrate and a driving circuit layer formed on the substrate. The driving circuit layer includes a plurality of switching devices, which are configured one-to-one with a plurality of pickup units to control the power on and power off of the corresponding electrical control units.

[0006] In one possible implementation, the electro-control device is a column made of an electrostrictive material, including polyvinylidene fluoride or polyvinylidene fluoride trifluoroethylene.

[0007] In one possible implementation, the concave surface is spherical in shape, with a chord length of L and a depth of H, satisfying the following condition: H = 1 / 2 * L * tanθ, where θ ranges from 5° to 30°.

[0008] In one possible implementation, the length of the chord L of the concave surface is 0.7 to 0.9 times the grain size of the light-emitting device.

[0009] In one possible implementation, the elongation of the control device when energized is d = 2 * H.

[0010] In one possible implementation, the end of the elastic member away from the transfer substrate also includes a plane disposed around the concave surface.

[0011] Secondly, embodiments of this application also propose a method for transferring light-emitting devices, comprising:

[0012] A carrier substrate and a target substrate are provided. The carrier substrate is provided with multiple light-emitting devices, and the target substrate is provided with multiple electrode pads. Multiple pickup devices of the transfer device described above are aligned and attached to the multiple light-emitting devices on the carrier substrate, so that the concave surface of the elastic element of the pickup unit contacts the surface of the corresponding light-emitting device to form a negative pressure. The multiple light-emitting devices are adsorbed to a predetermined distance above the multiple electrode pads of the target substrate, wherein the center distance between two adjacent electrode pads is equal to the center distance between two adjacent pickup units. The electrical control of the pickup device is energized to deform the concave surface into a convex surface and release the light-emitting device onto the corresponding electrode pad.

[0013] In one possible implementation, the target substrate is divided into sub-pixel areas of n colors, and each carrier substrate is used to carry multiple light-emitting devices of the same color. The process of adsorbing multiple light-emitting devices to a predetermined distance above multiple electrode pads of the target substrate includes: according to a predetermined color transfer order, transferring multiple light-emitting devices of the same color as the sub-pixel area from the carrier substrate of the corresponding color to the sub-pixel area of ​​the target substrate in sequence by picking units, wherein the center distance between two adjacent picking units in the transfer device is equal to n times the center distance between two adjacent light-emitting devices on the carrier substrate.

[0014] In one possible implementation, the target substrate is divided into sub-pixel areas of n colors, and each carrier substrate is used to carry multiple light-emitting devices of the same color. The process of adsorbing multiple light-emitting devices to a predetermined distance above multiple electrode pads on the target substrate includes: according to the predetermined color arrangement order on the target substrate, picking up multiple light-emitting devices of different colors sequentially from the carrier substrate of the corresponding color through a picking unit, and then transferring them to the sub-pixel area of ​​the target substrate, wherein the center distance between two adjacent light-emitting devices on the carrier substrate is equal to n times the center distance between two adjacent picking units in the transfer device.

[0015] According to the embodiments of this application, a light-emitting device transfer apparatus and method are provided. The transfer apparatus includes a transfer substrate and a plurality of pickup units arrayed on the transfer substrate. Each pickup unit includes an electrical control and an elastic element covering the outer periphery of the electrical control. The electrical control is electrically connected to the transfer substrate. The end of the elastic element away from the transfer substrate has a concave surface. When the concave surface contacts the surface of the light-emitting device, a negative pressure is formed to adsorb the light-emitting device. When energized, the electrical control can extend to deform the concave surface into a convex surface and release the light-emitting device. Thus, based on the principle of air pressure difference, multiple light-emitting devices are precisely adsorbed by the concave surface of the elastic element of the multiple pickup units, and the concave surface is deformed into a convex surface by the electrical control when energized, thereby achieving precise release of multiple light-emitting devices, simplifying the mass transfer process of light-emitting devices, and improving transfer efficiency. Attached Figure Description

[0016] The features, advantages, and technical effects of exemplary embodiments of the present application will now be described with reference to the accompanying drawings. In the drawings, the same components are referred to by the same reference numerals. The drawings are not drawn to scale and are only used to illustrate relative positions. The layer thicknesses in some areas are exaggerated for ease of understanding; the layer thicknesses in the drawings do not represent actual layer thickness proportions.

[0017] Figure 1 A schematic diagram showing the structural changes of the transfer device for the light-emitting device provided in the first embodiment of this application is shown;

[0018] Figure 2 Show Figure 1 A magnified schematic diagram of the pickup unit;

[0019] Figure 3 A flowchart illustrating the transfer method of the light-emitting device provided in the second embodiment of this application is shown;

[0020] Figure 4 A schematic diagram illustrating a transfer method for a light-emitting device;

[0021] Figure 5 A schematic diagram illustrating another method for transferring light-emitting devices.

[0022] Explanation of reference numerals in the attached figures:

[0023] 1. Substrate; 2. Driving circuit layer; 3. Pickup unit; 31. Electrical control unit; 32. Elastic element; 321. Concave surface; 322. Convex surface; 323. Planar surface;

[0024] T, carrier substrate; O, target substrate; W, electrode pad; Ld, light-emitting device. Detailed Implementation

[0025] The features and exemplary embodiments of various aspects of this application will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a comprehensive understanding of this application. However, it will be apparent to those skilled in the art that this application can be implemented without some of these specific details. The following description of embodiments is merely intended to provide a better understanding of this application by illustrating examples. In the accompanying drawings and the following description, at least some well-known structures and techniques are not shown to avoid unnecessarily obscuring the application; and, for clarity, the dimensions of the regional structures may be exaggerated. Furthermore, the features, structures, or characteristics described below can be combined in any suitable manner in one or more embodiments.

[0026] First Embodiment

[0027] Figure 1 A schematic diagram showing the structural changes of the transfer device for the light-emitting device provided in the first embodiment of this application is shown; Figure 2 Show Figure 1 A magnified schematic diagram of the pickup unit.

[0028] like Figure 1 and Figure 2 As shown, the light-emitting device transfer device provided in the first embodiment of this application includes a transfer substrate and a plurality of pickup units 3 arrayed on the transfer substrate. The pickup unit 3 includes an electrical control 31 and an elastic member 32 covering the outer periphery of the electrical control 31. The electrical control 31 is electrically connected to the transfer substrate. The end of the elastic member 32 away from the transfer substrate 1 has a concave surface 321. When the concave surface 321 contacts the surface of the light-emitting device Ld, it can form a negative pressure to adsorb the light-emitting device Ld. When the electrical control 31 is energized, it can extend to deform the concave surface 321 into a convex surface 322 and release the light-emitting device Ld.

[0029] Optionally, the light-emitting device Ld is a micro-LED or a mini-LED. The light energy distribution of the light-emitting device Ld exhibits a Lambaugh pattern, with the highest light energy at its center. Micro-LED refers to LED chips with a die size of less than 200 micrometers, while Mini-LED refers to LED chips with a die size of approximately 200-300 micrometers. Mini-LEDs or Micro-LEDs can be used as self-emissive display elements, offering advantages such as low power consumption, high brightness, high resolution, high color saturation, fast response speed, long lifespan, and high efficiency. Furthermore, the terms "micro-LED" or "mini-LED" refer to the entire light-emitting structure formed in each step of manufacturing the light-emitting device Ld, including all layers or regions already formed.

[0030] When the power is off, the end of the elastic member 32 covering the outer periphery of the pickup unit 31 away from the transfer substrate 1 has a concave surface 321. When the concave surface 321 contacts the surface of the light-emitting device Ld on the carrier substrate T, the resulting internal air pressure is lower than the external atmospheric pressure, i.e., the internal cavity is in a negative pressure state. This allows the light-emitting device Ld to be adsorbed onto the elastic member 32 and transferred to the corresponding position on the target substrate O. Then, a predetermined voltage value is applied to the electronic member 31 through the transfer substrate. When energized, the electronic member 31 can extend, causing the concave surface 321 of the elastic member 32 to deform into a convex surface 322. By changing the shape of the elastic member 32, the currently formed negative pressure state can be broken, releasing the light-emitting device Ld, allowing it to fall onto the corresponding position on the target substrate under its own gravity, thus completing the transfer process of the light-emitting device Ld.

[0031] According to the light-emitting device transfer device provided in the embodiments of this application, based on the principle of air pressure difference, multiple light-emitting devices Ld are precisely adsorbed by the concave surface 321 of the elastic element 32 of multiple pickup units 3, and the concave surface 321 is deformed into a convex surface 322 by the electrical control 31 when energized, thereby realizing the precise release of multiple light-emitting devices Ld, simplifying the mass transfer process of light-emitting devices Ld and improving the transfer efficiency.

[0032] Furthermore, the transfer substrate includes a substrate 1 and a driving circuit layer 2 formed on the substrate 1. The driving circuit layer 2 includes multiple switching devices, which are arranged one-to-one with multiple pickup units 3 to control the power on and power off of the corresponding electrical control 31.

[0033] Optionally, the substrate 1 is a glass substrate. The light-emitting device Ld adopts COB (Chips on Board) or COG (Chips on Glass) technology, and is adhered to the substrate 1 with conductive or non-conductive adhesive, and then electrically connected by wire bonding. It does not require a support frame, gold wire, etc., uses fewer materials, and can reduce one reflow soldering in the process, avoiding the risk of secondary reflow.

[0034] The driving circuit layer 2 is formed on the substrate 1 through etching and other processes. The switching device is a thin-film transistor, which is electrically connected to the electrical control 31 through gold wire bonding and other processes. Each electrical control 31 can be controlled individually to realize power-on and power-off. Compared with using one switching device to control multiple or even all electrical control 31, the corresponding pickup unit 3 can be activated according to the arrangement and spacing of the light-emitting device Ld to be transferred, thereby improving the applicability of the transfer device.

[0035] Furthermore, the control unit 31 is a column made of electrostrictive material, including polyvinylidene fluoride or polyvinylidene fluoride trifluoroethylene, so that the length of the control unit 31 changes when energized and adjusts the amount of expansion and contraction according to the voltage value, and can return to its original shape when the power is off.

[0036] like Figure 1 As shown, the interface between the electrical control 31 and the elastic element 32 is a plane. When the electrical control 31 is energized and pressure is applied, it extends along its own length, causing the plane at the interface to bulge and deform, and pushing the concave surface 321 of the elastic element 32 to deform into a convex surface 322.

[0037] In some embodiments, the concave surface 321 is spherical in shape, with a chord length of L and a depth of H, and satisfies the following condition: H = 1 / 2 * L * tanθ, where θ ranges from 5° to 30°.

[0038] like Figure 2 As shown, when the value of θ is less than 5°, the depth H of the concave surface 321 is shallow, and the cavity between it and the surface of the light-emitting device Ld is prone to air leakage and cannot form a negative pressure. When the value of θ is greater than 30°, the depth H of the concave surface 321 is too deep and may not be able to deform into a convex surface 322 when the control component 31 is energized. In one example, θ = 10°, which can both form a negative pressure state in the cavity between the concave surface 321 and the surface of the light-emitting device Ld and deform into a convex surface 322 when the control component 31 is energized.

[0039] Furthermore, the length of the chord L of the concave surface 321 is 0.7 to 0.9 times the grain size of the light-emitting device Ld.

[0040] As mentioned earlier, Micro-LED refers to LED chips with a die size of less than 200 micrometers, while Mini-LED refers to LED chips with a die size of approximately 200 to 300 micrometers. To enable the concave surface 321 to adsorb the light-emitting device Ld, the chord length L of the concave surface 321 is 0.7 to 0.9 times the die size of the light-emitting device Ld, for example, 0.8, to prevent the light-emitting device Ld from detaching during the adsorption process. The value of the chord length L can, for example, be in the range of 20 μm to 300 μm.

[0041] Furthermore, the elongation d of the control component 31 when energized is 2*H, meaning that the height of the convex surface 322 is the same as the depth of the concave surface 321. Therefore, the supply voltage of the switching device can be calculated based on parameters such as the elongation rate of the control component 31.

[0042] In some embodiments, the end of the elastic member 32 away from the transfer substrate 1 further includes a plane 323 disposed around the concave surface 321. For example... Figure 1As shown, plane 323 also contacts the surface of the light-emitting device Ld, increasing the adsorption force and preventing the light-emitting device Ld from falling off during the transfer process.

[0043] Second Embodiment

[0044] Figure 3 A flowchart illustrating the transfer method of the light-emitting device provided in the second embodiment of this application is shown.

[0045] like Figure 3 As shown, the transfer method of the light-emitting device provided in the second embodiment of this application includes the following steps S1 to S4.

[0046] Step S1: Provide a carrier substrate T and a target substrate O. The carrier substrate T is provided with multiple light-emitting devices Ld, and the target substrate O is provided with multiple electrode pads W.

[0047] The light-emitting device (Ld) can be a blue light chip with a main wavelength in the range of 440nm-470nm. Optionally, the light-emitting device Ld has a flip-chip structure. Each light-emitting device Ld may include a first electrode and a second electrode. When the light-emitting device Ld has a flip-chip structure, the first electrode and the second electrode are located on the same side of the light-emitting device Ld. The light-emitting device Ld is electrically connected to the corresponding electrode pads W through the first electrode and the second electrode. Optionally, the light-emitting device Ld can be adhered to the carrier substrate T with a weak adhesive, or the carrier substrate T can have multiple grooves in which the light-emitting device Ld is accommodated.

[0048] Step S2: Align and attach the multiple pickup devices 3 of the transfer device as described above to the multiple light-emitting devices Ld on the carrier substrate T, so that the concave surface 321 of the elastic member 32 of the pickup unit 3 contacts the surface of the corresponding light-emitting device Ld to form a negative pressure.

[0049] Step S3: Adsorb multiple light-emitting devices Ld to a predetermined distance above multiple electrode pads W on the target substrate O, wherein the center distance between two adjacent electrode pads W is equal to the center distance between two adjacent pickup units 3; the predetermined distance is slightly higher than the sum of the heights of the light-emitting devices Ld and the electrode pads W, which can ensure that the light-emitting devices Ld will not tip over after being released.

[0050] Step S4: Power on the electrical control 31 of the pickup device to deform the concave surface 321 into a convex surface 322, and release the light-emitting device Ld onto the corresponding electrode pad W. Optionally, the light-emitting device Ld and the electrode pad W are electrically connected by bonding or binding.

[0051] Figure 4 A schematic diagram illustrating a method for transferring light-emitting devices.

[0052] In one example, the target substrate O is divided into sub-pixel regions of n colors, and each carrier substrate T is used to carry multiple light-emitting devices Ld of the same color. In step S3, attaching the multiple light-emitting devices Ld to a predetermined distance above the multiple electrode pads W of the target substrate O includes:

[0053] According to a preset color transfer order, multiple light-emitting devices Ld with the same color as the sub-pixel area are sequentially transferred from the corresponding color carrier substrate T to the sub-pixel area of ​​the target substrate O via the pickup unit 3. The center-to-center distance between two adjacent pickup units 3 in the transfer device is equal to n times the center-to-center distance between two adjacent light-emitting devices Ld on the carrier substrate T. Of course, the number of color types n can also be four or more.

[0054] like Figure 4 As shown, the light-emitting device Ld has three colors: red, green and blue. The center distance between two adjacent pickup units 3 in the transfer device is equal to three times the center distance between two adjacent light-emitting devices Ld on the carrier substrate T.

[0055] The preset color transfer order is, for example, red, green, and blue. Multiple pickup units 3 transfer multiple red light-emitting devices (Ld) on the red carrier substrate T together to the red sub-pixel area of ​​the target substrate O. Then, the green and blue light-emitting devices (Ld) are sequentially transferred together to the green and blue sub-pixel areas of the target substrate O. Since the center-to-center distance between two adjacent pickup units 3 in the transfer device is equal to three times the center-to-center distance between two adjacent light-emitting devices (Ld) on the carrier substrate T, there is no interference between the light-emitting devices (Ld) of different colors. There is also no interference between the existing light-emitting devices (Ld) on the target substrate O and the light-emitting devices (Ld) on the transfer substrate, allowing for a one-time transfer to the corresponding positions on the target substrate O.

[0056] Figure 5 A schematic diagram illustrating another method for transferring light-emitting devices.

[0057] In another example, the target substrate O is divided into n sub-pixel regions of different colors, and each carrier substrate T is used to carry multiple light-emitting devices Ld of the same color. In step S3, attaching the multiple light-emitting devices Ld to a predetermined distance above the multiple electrode pads W of the target substrate O includes:

[0058] According to the preset color arrangement order on the target substrate O, multiple pickup units 3 sequentially adsorb multiple light-emitting devices Ld of different colors from the corresponding color carrier substrate T, and then transfer them to the sub-pixel area of ​​the target substrate O. The center-to-center distance between two adjacent light-emitting devices Ld on the carrier substrate T is equal to n times the center-to-center distance between two adjacent pickup units 3 in the transfer device. Of course, the number of colors n can also be four or more.

[0059] like Figure 5 As shown, the light-emitting device Ld has three colors: red, green and blue. The center distance between two adjacent light-emitting devices Ld on the carrier substrate T is equal to three times the center distance between two adjacent pickup units 3 in the transfer device.

[0060] The preset color transfer order is, for example, red, green, and blue. Multiple picking units 3 sequentially adsorb multiple light-emitting devices Ld of the corresponding colors from the red carrier substrate T, the green carrier substrate T, and the blue carrier substrate T, and then transfer them together to the corresponding sub-pixel areas of the target substrate O. Similarly, the light-emitting devices Ld of each color will not interfere with each other, and there will be no interference between the light-emitting devices Ld already on the target substrate O and the light-emitting devices Ld on the transfer substrate.

[0061] It should be readily understood that the terms “on,” “above,” and “on top of” in this application should be interpreted in the broadest possible sense, such that “on” means not only “directly on something” but also “on something” with an intermediate feature or layer therebetween, and that “above” or “on top of” means not only “on top of something” but also “on top of something” without an intermediate feature or layer therebetween (i.e., directly on something).

[0062] As used herein, the term "layer" can refer to a portion of material comprising a region of a certain thickness. A layer may extend over the entire underlying or overlying structure, or may have a smaller extent than the underlying or overlying structure. Furthermore, a layer may be a region of a homogeneous or non-homogeneous continuous structure, with a thickness less than the thickness of that continuous structure. For example, a layer may be located between the top and bottom surfaces of the continuous structure, or between any pair of transverse planes at the top and bottom surfaces. A layer may extend laterally, vertically, and / or along a tapered surface.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application 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 therein. Such 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 this application.

Claims

1. A transfer device for a light-emitting device, characterized in that, The device includes a transfer substrate and a plurality of pickup units arrayed on the transfer substrate. Each pickup unit includes an electrical control and an elastic element covering the outer periphery of the electrical control. The electrical control is electrically connected to the transfer substrate. One end of the elastic element away from the transfer substrate has a concave surface. When the concave surface contacts the surface of a light-emitting device, it can generate a negative pressure to attract the light-emitting device. When energized, the electrical control can extend to deform the concave surface into a convex surface and release the light-emitting device. The concave surface is spherical in shape, with a chord length of L and a depth of H, satisfying the following condition: H = 1 / 2 * L * tanθ, where θ ranges from 5° to 30°.

2. The transfer device according to claim 1, characterized in that, The transfer substrate includes a substrate and a driving circuit layer formed on the substrate. The driving circuit layer includes a plurality of switching devices, which are configured one-to-one with a plurality of pickup units to control the power on and power off of the corresponding electrical control units.

3. The transfer device according to claim 1, characterized in that, The electrostrictive control is a column made of an electrostrictive material, including polyvinylidene fluoride or polyvinylidene fluoride. trifluoroethylene.

4. The transfer device according to claim 1, characterized in that, The length of the chord L of the concave surface is 0.7 to 0.9 times the grain size of the light-emitting device.

5. The transfer device according to claim 1, characterized in that, The elongation of the electrical control when energized is d=2*H.

6. The transfer device according to claim 1, characterized in that, The end of the elastic element away from the transfer substrate also includes a plane disposed around the concave surface.

7. A method for transferring light-emitting devices, characterized in that, include: A carrier substrate and a target substrate are provided, wherein a plurality of light-emitting devices are disposed on the carrier substrate and a plurality of electrode pads are disposed on the target substrate; The multiple pickup units of the transfer device as described in any one of claims 1 to 6 are aligned and attached to the multiple light-emitting devices on the carrier substrate, so that the concave surface of the elastic element of the pickup unit contacts the surface of the corresponding light-emitting device to form a negative pressure. Multiple light-emitting devices are adsorbed onto multiple electrode pads of a target substrate at a predetermined distance above them, wherein the center distance between two adjacent electrode pads is equal to the center distance between two adjacent pickup units. The electrical control of the pickup unit is energized to deform the concave surface into a convex surface and release the light-emitting device onto the corresponding electrode pad.

8. The transfer method according to claim 7, characterized in that, The target substrate is divided into n sub-pixel areas of different colors. Each carrier substrate is used to carry multiple light-emitting devices of the same color. The step of attaching the multiple light-emitting devices to a predetermined distance above the multiple electrode pads of the target substrate includes: According to a preset color transfer order, multiple light-emitting devices with the same color as the sub-pixel area are sequentially transferred from the carrier substrate of the corresponding color to the sub-pixel area of ​​the target substrate by the picking unit. The center distance between two adjacent picking units in the transfer device is equal to n times the center distance between two adjacent light-emitting devices on the carrier substrate.

9. The transfer method according to claim 7, characterized in that, The target substrate is divided into n sub-pixel areas of different colors. Each carrier substrate is used to carry multiple light-emitting devices of the same color. The step of attaching the multiple light-emitting devices to a predetermined distance above the multiple electrode pads of the target substrate includes: According to the preset color arrangement order on the target substrate, the picking unit sequentially picks up multiple light-emitting devices of different colors from the carrier substrate of the corresponding color, and then transfers them to the sub-pixel area of ​​the target substrate. The center distance between two adjacent light-emitting devices on the carrier substrate is equal to n times the center distance between two adjacent picking units in the transfer device.

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