LED conveyor

Abstract

The present disclosure relates to a light emitting diode (LED) conveying device, which includes: a pick-up unit configured to lift at least a portion of a plurality of LEDs disposed on a first substrate by receiving a control signal, and to place selected LEDs among the lifted LEDs onto a second substrate; and a controller configured to transmit a control signal to the pick-up unit so that the pick-up unit individually lifts or places each of the plurality of LEDs.

Description

Technical Field

[0001] This application claims the benefit of Korean Patent Application No. 10-2019-0173978 filed in Korea on December 24, 2019.

[0002] The present disclosure relates to a device for manufacturing a light emitting diode (LED), and more particularly, to an LED delivery device. Background Art

[0003] Various display devices with light weight and flexible characteristics have been developed. Among these display devices, liquid crystal display devices and organic light emitting display devices have been applied to common electronic devices, for example, smart phones, computers such as laptop computers, and have been applied to other devices. Such display devices have limitations in reducing the size of the border area. For example, since a sealant must be used to seal the liquid crystal and to bond the upper substrate and the lower substrate in the liquid crystal display device, there are limitations in reducing the size of the border area. In addition, because the organic light emitting element in the organic light emitting display device is made of an organic material that is very susceptible to moisture or oxygen, and thus requires a package for protecting the element, there are limitations in reducing the size of the border area. When a plurality of liquid crystal display devices or organic light emitting display devices are arranged in a tiled form to achieve a large display area, there is a problem of easily distinguishing the border area between adjacent panels during use.

[0004] As an alternative to these display devices, display devices using small light-emitting diodes (LEDs) have been developed. Since LEDs are made of inorganic materials rather than organic materials, they have excellent reliability and therefore longer life than liquid crystal display devices or organic light-emitting display devices. In addition, LED is a device suitable for application to very large display areas because it not only emits light quickly, but can also be driven with less power consumption, has excellent stability due to high impact resistance, and can display high-brightness images. In short, a display device using small LEDs as a light-emitting element can be implemented without a frame, and therefore, is advantageous for application to very large display devices when multiple display devices are subsequently manufactured.

[0005] Since it is necessary to ensure productivity for commercialization of such small-sized LED display devices, various studies and researches are conducted to improve the productivity and efficiency of LED display devices. Summary of the invention

[0006] Technical issues

[0007] An object of the present disclosure is to provide a device capable of efficiently delivering a desired number of light emitting diodes.

[0008] In particular, an object of the present disclosure is to provide a delivery device capable of selectively delivering a desired number of light emitting diodes among a plurality of light emitting diodes.

[0009] The purposes and tasks of the present disclosure are not limited to the above-mentioned purposes and tasks, and those skilled in the art will clearly understand other purposes and tasks not disclosed herein based on the following description.

[0010] Technical Solution

[0011] The present disclosure provides a light-emitting diode conveying device, which includes: a picking unit, configured to lift at least a portion of a plurality of light-emitting diodes arranged on a substrate by receiving a control signal, and to place selected ones of the lifted light-emitting diodes onto another substrate; and a controller, configured to transmit a control signal to the picking unit so that the picking unit individually lifts or places each of the plurality of light-emitting diodes.

[0012] The pickup unit may include a head including a plurality of detachable units configured to contact each of the plurality of light emitting diodes.

[0013] The head may include a plate and a stamp, the plate being connected to a conveying arm configured to move the head, wherein one surface of the stamp may be configured to contact the plate, and another surface of the stamp may be configured to contact the plurality of light emitting diodes, and the detachable unit may be protrudingly arranged on the other surface of the stamp.

[0014] The stamp may comprise an elastomer.

[0015] As an example, each of the plurality of detachable units may include a first electrode; a second electrode spaced apart from the first electrode facing the ground; a variable portion disposed between the first electrode and the second electrode, the variable portion having a size that can be changed by an electrical signal applied by the first electrode and the second electrode; and an adhesive portion detachably attached to at least one of the plurality of light-emitting diodes.

[0016] The first electrode may include a plurality of strip-shaped electrodes, and the variable portion may be arranged corresponding to each of the plurality of strip-shaped electrodes.

[0017] For example, the variable portion may be configured to expand or contract in a predetermined sequence.

[0018] Alternatively, the first electrode may include a plurality of strip-shaped electrodes having concentric circle or concentric ring shapes, and the plurality of strip-shaped electrodes may be separated from each other.

[0019] In this case, the detachable unit may include a wire connected to each of the plurality of strip-shaped electrodes.

[0020] Alternatively, the first electrode may include a plurality of strip-shaped electrodes extending along a first direction, and the second electrode may include a plurality of strip-shaped electrodes extending along a second direction intersecting the first direction.

[0021] In this case, the variable portion may be located at a position where any one of the plurality of strip-shaped electrodes extending in the first direction intersects with any one of the plurality of strip-shaped electrodes extending in the second direction.

[0022] Alternatively, the first electrode may include a plurality of strip-shaped electrodes having concentric circle or concentric ring shapes, and the plurality of strip-shaped electrodes may be electrically connected to each other.

[0023] In this case, the plurality of strip-shaped electrodes may have different thicknesses from each other.

[0024] For example, a center strip electrode among the plurality of strip electrodes may be the thickest.

[0025] Multiple strip electrodes may be gradually lowered from the center to the periphery.

[0026] Alternatively, the variable portion provided corresponding to the central strip-shaped electrode may expand or contract before the variable portions corresponding to the other strip-shaped electrodes expand or contract.

[0027] The variable portion may include an electroactive polymer.

[0028] For example, the variable portion may include a polymer selected from the group consisting of polyvinylidene fluoride, poly(vinylidene fluoride-co-trifluoroethylene), polydimethylsiloxane, an electroactive polymer, a liquid crystal elastomer, and copolymers thereof.

[0029] The adhesive part may include a polymer selected from the group consisting of polydimethylsiloxane, polyamic acid, and a combination thereof.

[0030] The plurality of detachable units may have different heights from each other.

[0031] Beneficial Effects

[0032] The light emitting diode (LED) delivery device of the present disclosure may select a desired portion and / or a desired number of LEDs among a plurality of LEDs, and transmit and / or deliver the selected LEDs.

[0033] The LED conveying device of the present disclosure can correctly install the LED at a predetermined position, which can improve the productivity of the LED display device. The technical effects of the present disclosure are not limited to the above-exemplified effects, and include more various effects in this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic perspective view showing an LED display device according to an exemplary embodiment of the present disclosure.

[0035] Figure 2 is a schematic cross-sectional view illustrating a display area of ​​an LED display device according to an exemplary embodiment of the present disclosure.

[0036] Figure 3 is a schematic cross-sectional view showing an LED according to an exemplary embodiment of the present disclosure.

[0037] Figure 4 is a schematic diagram illustrating an LED delivery device according to an exemplary embodiment of the present disclosure.

[0038] Figure 5 is a schematic perspective view illustrating a structure of a stamp having a detachable unit constituting an LED delivery device according to an exemplary embodiment of the present disclosure.

[0039] Figure 6 is a schematic cross-sectional view illustrating a structure of a stamp having a detachable unit constituting an LED delivery device according to an exemplary embodiment of the present disclosure.

[0040] Figure 7 is a schematic plan view illustrating a structure of a detachable unit according to an exemplary embodiment of the present disclosure.

[0041] Figures 8 to 10 is a schematic cross-sectional view illustrating a process of attaching an LED through a detachable unit according to an exemplary embodiment of the present disclosure.

[0042] Fig.11 is a schematic plan view illustrating a structure of a detachable unit according to another exemplary embodiment of the present disclosure.

[0043] Fig.12 is a schematic cross-sectional view illustrating a structure of a detachable unit according to another exemplary embodiment of the present disclosure.

[0044] Fig.13 is a schematic plan view illustrating a structure of a detachable unit according to still another exemplary embodiment of the present disclosure.

[0045] Figures 14 to 17 is a schematic cross-sectional view illustrating a process of attaching an LED through a detachable unit according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION

[0046] According to the embodiments described in detail below in conjunction with the accompanying drawings, the advantages and features of the present disclosure and the methods for realizing them will become apparent. However, the present disclosure is not limited to the embodiments described below, but will be implemented in various forms. It should be understood that the following embodiments are provided only to complete the present disclosure and fully inform the ordinary technicians in the field to which the present disclosure belongs, and the scope of the present disclosure is limited by the attached claims.

[0047] The shapes, proportions, angles, quantities, etc. shown in the drawings for describing the exemplary embodiments of the present disclosure are exemplary, and therefore the present disclosure is not limited to the contents shown. Throughout the specification, the same reference numerals represent the same elements. In addition, when describing the present disclosure, if it is determined that the detailed description of the related known technology may unnecessarily make the subject matter of the present disclosure difficult to understand, its detailed description will be omitted. When "including", "having", "comprising", etc. are mentioned in this article, other parts or elements may be added unless "only" is used. When expressing an element in the singular, unless otherwise explicitly stated, plural elements are included. When explaining an element, even if there is no clear description, it should be interpreted as including a margin of error.

[0048] In the case of describing a positional relationship, for example, when describing the positional relationship of two parts or elements, for example, "on", "above", "below", "next to", unless "directly" or "directly" is used, one or more parts or elements may be arranged between the two parts or elements. When a device or layer is referred to as being "on" another device or layer, the device or layer is directly located on the other device or layer, or there are any intermediate devices or layers between them. When describing an element as being "connected", "coupled" or "bonded" to another element, it should be understood that the element may be directly connected or bonded to the other element, but other elements may be inserted between each element, or each element may be "connected", "coupled" or "bonded" through other elements.

[0049] Although first, second, etc. are used to describe various elements, these elements are not limited by these terms. These terms are only used to distinguish one element from another element. Therefore, within the spirit of the present disclosure, the first element described below can be a second element. For ease of description, the size and thickness of each element shown in the accompanying drawings are shown, and the present disclosure is not limited to the size and thickness of the elements shown. Hereinafter, various exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0050] Figure 1 is a schematic perspective view showing a light emitting diode (LED) display device according to an exemplary embodiment of the present disclosure. Figure 1As shown, the LED display device 100 includes a plurality of pixels P arranged on a substrate 110. The pixel P may include a red sub-pixel 140R, a green sub-pixel 140G, and a blue sub-pixel 140B.

[0051] Thin film transistor TFT ( Figure 2 ) and LED 140 ( Figure 2 ) may be located in each of the sub-pixels 140R, 140G, and 140B. The LED 140 and the thin film transistor TFT may be connected to a driving portion such as a gate control circuit, a data control circuit, etc. through lines such as a gate line, a data line, etc. When the chip size (width) of the LED 140 is 100 μm or less, it is also referred to as a micro LED display device. On the other hand, if the chip size of the LED 140 is about several hundred microns, it is also referred to as a miniature LED display device.

[0052] The LED 140 may be manufactured separately from the array process of the substrate 110. Although the thin film transistor TFT and the light emitting element are manufactured by a photo process in the organic light emitting display device, the LED 140 may be manufactured in a separate process and then transferred to the substrate 110 in the LED display device. As an example, the LED 140 may be manufactured by growing an inorganic material such as Al, Ga, N, P, As, In, etc. on a growth substrate (e.g., a sapphire substrate or a silicon substrate) and then separating the grown inorganic material from the growth substrate.

[0053] Figure 2 is a schematic cross-sectional view showing a display area of ​​an LED display device according to an exemplary embodiment of the present disclosure. Figure 2 As shown, an active area for displaying an image and an inactive area surrounding the active area may be defined in the LED display device 100. A light emitting element (e.g., LED 140) and a driving element (e.g., thin film transistor TFT) for driving the light emitting element may be arranged in the active area. The inactive area is an area where no image is displayed, and various lines and control circuits connected to the elements arranged in the active area may be arranged in the inactive area. Figure 2 In the LED display device 100 according to the exemplary embodiment of the present disclosure, various functional components are stacked on the substrate 110. For example, the substrate 110 may include glass, resin, polymer, or plastic. In some embodiments, the substrate 110 may be made of a material having flexibility or foldability.

[0054] The thin film transistor TFT may include a gate electrode 101 disposed on a substrate 110 , a gate insulating layer 112 covering the gate electrode 101 , a semiconductor layer 103 disposed on the gate insulating layer 112 , and a source electrode 105 and a drain electrode 107 disposed on the semiconductor layer 103 .

[0055] The gate electrode 101 may be made of Cr, Ta, Cu, Ti, Al or an alloy thereof, and the gate insulating layer 112 may have a single-layer structure or a multi-layer structure. Each gate insulating layer 112 may include a silicon-based material such as SiO x or SiN x Inorganic insulating materials.

[0056] The semiconductor layer 103 may include an amorphous semiconductor such as amorphous silicon or an oxide semiconductor such as IGZO (indium gallium zinc oxide), TiO2, ZnO, WO3, and SnO2. The semiconductor layer 103 of the thin film transistor TFT is not limited to the above-mentioned specific materials, and the semiconductor layer 103 may include all kinds of semiconductor materials used in current thin film transistors.

[0057] The source electrode 105 and the drain electrode 107 may be made of a metal such as Cr, Mo, Ta, Cu, Ti, Al, etc., or an alloy thereof. The drain electrode 107 serves as a first electrode for applying a signal to the LED 140 .

[0058] Although Figure 2 The thin film transistor TFT shown in FIG. 1 is a bottom gate thin film transistor, but other types of thin film transistors such as a top gate thin film transistor may also be applied to the LED display device 100 of the present disclosure.

[0059] The second electrode 109 is disposed on the gate insulating layer 112 in the active region. The second electrode 109 may be made of Cr, Mo, Cu, Ti, Al or alloys thereof, and may be manufactured by the same process as the drain electrode 107 of the thin film transistor TFT.

[0060] The first insulating layer 114 is disposed on the source electrode 105, the drain electrode 107 and the second electrode 109, and the LED 140 is disposed on the first insulating layer 114. Figure 2 In one aspect, a portion of the first insulating layer 114 is removed and the LED 140 is arranged in the removed area, but the first insulating layer 114 may not be removed. The first insulating layer 114 may be an organic layer including photo-acryl or a layer such as SiO x or SiN x Alternatively, the first insulating layer 114 may have a double-layer structure of an inorganic layer / organic layer or a triple-layer structure of an inorganic layer / organic layer / inorganic layer.

[0061] The second insulating layer 116 is disposed on the first insulating layer 114. The second insulating layer 116 may be an organic layer of photo-acrylic or SiO x or SiN xAlternatively, the second insulating layer 116 may have a double-layer structure of an inorganic layer / organic layer or a triple-layer structure of an inorganic layer / organic layer / inorganic layer, and cover an upper region of the LED 140.

[0062] A first contact hole 114a and a second contact hole 114b are formed in the first insulating layer 114 and the second insulating layer 116 over the thin film transistor TFT and the second electrode 109. The drain electrode 107 and the second electrode 109 of the thin film transistor TFT are exposed to the outside through the first contact hole 114a and the second contact hole 114b, respectively. In addition, a third contact hole 116a and a fourth contact hole 116b are formed in the second insulating layer 116 over the p-type electrode 141 of the LED 140 and the n-type electrode 143 of the LED 140, respectively. The p-type electrode 141 and the n-type electrode 143 are exposed to the outside through the third contact hole 116a and the fourth contact hole 116b, respectively.

[0063] A first connection electrode 117a and a second connection electrode 117b, each made of a transparent metal oxide such as ITO, IGZO, and IGO, are disposed on the second insulating layer 116. The drain electrode 107 of the thin film transistor TFT and the p-type electrode 141 of the LED 140 are electrically connected to the first connection electrode 117a through the first contact hole 114a and the third contact hole 116a, respectively. In addition, the second electrode 109 and the n-type electrode 143 are electrically connected to the second connection electrode 117b through the second contact hole 114b and the fourth contact hole 116b, respectively.

[0064] A buffer layer 118 made of an inorganic material and / or an organic material may be disposed over the substrate 110 to cover and protect the LED 140 .

[0065] Figure 3 1 is a schematic cross-sectional view showing an LED according to an exemplary embodiment of the present disclosure. As an example, LED 140 may be a micro-LED having a size of 10 μm to 100 nm. LED 140 may include an undoped GaN layer 144, an n-type GaN layer 145 disposed on the undoped GaN layer 144, an active layer 146 disposed on the n-type GaN layer 145 and having a multi-quantum well (MQW) structure, a p-type GaN layer 147 disposed above the active layer 146, an ohmic contact layer 148 made of a transparent conductive material and disposed on the p-type GaN layer 147, a p-type electrode 141 contacting a portion of the ohmic contact layer 148, and an n-type electrode 143 contacting a portion of the n-type GaN layer 145 exposed by etching a portion of the active layer 146, the p-type GaN layer 147, and the ohmic contact layer 148.

[0066] The n-type GaN layer 145 is a layer that supplies electrons to the active layer 146 and may be formed by doping a GaN semiconductor layer with n-type impurities such as Si.

[0067] The active layer 146 is a layer where injected electrons and holes recombine to emit light. The MQW structure in the active layer 146 has a plurality of barrier layers and well layers that alternate. As an example, the well layer may be an InGaN layer, and the barrier layer may be a GaN layer, but is not limited thereto.

[0068] The p-type GaN layer 147 is a layer that provides holes to the active layer 146 and may be formed by doping a GaN semiconductor layer with p-type impurities such as Mg, Zn, and Be.

[0069] The ohmic contact layer 148 allows the p-type GaN layer 147 to ohmically contact the p-type electrode 141 , and may include, but is not limited to, transparent metal oxides such as ITO (Indium Tin Oxide), IGZO (Indium Gallium Zinc Oxide), and IZO (Indium Zinc Oxide).

[0070] Each of the p-type electrode 141 and the n-type electrode 143 may have a single-layer structure or a multi-layer structure, each layer of which is made of at least one metal of Ni, Au, Pt, Ti, Al, Cr or an alloy thereof.

[0071] When voltage is applied to the p-type electrode 141 and the n-type electrode 143 in the LED 140 having the above structure, and thus holes and electrons are injected from the n-type GaN layer 145 and the p-type GaN layer 147 into the active layer 145, excitons are generated in the active layer 146. As the generated excitons decay in the active layer 146, light corresponding to the energy gap between the LUMO (lowest unoccupied molecular orbital) energy level and the HOMO (highest occupied molecular orbital) energy level is generated to be emitted outward. The wavelength of light emitted from the LED 140 can be adjusted by adjusting the thickness of the barrier layer in the MQW structure of the active layer 146.

[0072] LED 140 can be manufactured by forming a buffer layer on a growth substrate and growing a GaN thin film on the buffer layer. The substrate for growing the GaN thin film may include but is not limited to sapphire, silicon (Si), GaN, silicon carbide (SiC), GaAs, ZnO, etc.

[0073] When the substrate for growing the GaN thin film is made of a material other than GaN and the buffer layer may include AlN or GaN, the buffer layer prevents quality degradation caused by lattice mismatch caused during the process of directly growing the n-type GaN layer 145 of the epitaxial layer on the growth substrate.

[0074] The n-type GaN layer 145 may be manufactured by growing an undoped GaN layer 144 and then doping an n-type impurity such as Si on the undoped GaN layer 144. Similarly, the p-type GaN layer 147 may be manufactured by growing an undoped GaN layer and then doping a p-type impurity such as Mg, Zn, Be, etc.

[0075] like Figure 1 and 2 As shown, the LED 140 is transferred to the substrate 110 used in the LED display device 100 .

[0076] In this case, the process of delivering the LED 140 from the growth substrate or the production substrate to the display device is called transfer.

[0077] Currently, two or more LEDs are usually arranged in one sub-pixel 140R, 140G or 140B ( Figure 1 ) in order to cope with LED failures generated during the manufacturing and / or transfer process. However, with the increase in the number of sub-pixels in display devices that have developed to high resolution, the number of LEDs to be transferred becomes too large if the prepared LEDs are taken into account. This is a huge loss in production time and cost. In addition, when all the LEDs arranged in two or more sub-pixels are defective, the sub-pixels 140R, 140G and 140G cannot be repaired, so there is a problem of product quality degradation. In addition, the current technology is to transfer all LEDs on one substrate to another substrate, and therefore, it is impossible to transfer only a selected portion of the LEDs on one substrate. Therefore, even if a defective LED is found during inspection, it is difficult to separate or exclude the defective LED during the transfer process.

[0078] The inventors have recognized the shortcomings in current LED delivery processes and devices, and have designed a delivery device that can provide transfer or delivery selectivity of LEDs and increase installation accuracy.

[0079] Figure 4 is a schematic diagram showing an LED delivery device according to an exemplary embodiment of the present disclosure, Figure 5 is a schematic perspective view showing a structure of a stamp having a detachable unit constituting an LED delivery device according to an exemplary embodiment of the present disclosure, Figure 6 is a schematic cross-sectional view illustrating a structure of a stamp having a detachable unit constituting an LED delivery device according to an exemplary embodiment of the present disclosure.

[0080] The LED delivery device according to an exemplary embodiment of the present disclosure may include a plurality of functional units. Hereinafter, the LED delivery device will be described with a focus on the pickup unit 210 that lifts the LED 140 from one substrate (e.g., a growth substrate) and puts the LED 140 down on another substrate (e.g., a display substrate). The LED 140 may be a micro LED having a chip size (width) of 100 micrometers (μm) or less.

[0081] The LED delivery device 200 may include a controller 202 to control a plurality of functional units including the pickup unit 210 . Figure 4 The substrate 10 shown is a substrate before the LED is delivered, and may be a growth substrate for generating the LED 140, or a substrate for the LED 140 to be finally mounted and transferred to the LED display device 100 ( Figure 1 and 2 ) before conveying the substrate.

[0082] The pick-up unit 210 is configured to selectively transfer and convey the LEDs 140. In particular, the pick-up unit 210 is configured to lift at least some of the plurality of LEDs 140 arranged on one substrate 10 by a control signal received from the controller 202, and to place selected LEDs 140 among the lifted LEDs 140 onto other substrates. To this end, the pick-up unit 210 is configured to independently lift and / or place each LED 140. For example, the pick-up unit 210 may have a plurality of detachable units 235 configured to contact, lift, and place each of the plurality of LEDs 140.

[0083] As an exemplary embodiment, the pickup unit 210 may include a head 230 provided with a plurality of detachable units 235 and a delivery arm 220 configured to move the head 230. Meanwhile, the controller 202 controls the LED 140 to be attached to or detached from the detachable unit 230 by transmitting a control signal. In addition, the LED delivery device 200 may further include a support 240 configured to place one substrate 10 or other substrates thereon. In another exemplary embodiment, the support 240 may be configured separately from the LED delivery device 200.

[0084] The head 230 may include a plate 231 connected to the conveying arm 220, and a stamp 232 below the plate 231. One surface of the stamp 232 is bonded to the plate 231, and the other surface of the stamp 232 configured to contact the LED 140 includes a detachable unit 235. In the figure, the plate 231 and the stamp 232 are shown separately, but the two elements may be formed integrally. That is, the stamp having the detachable unit 235 on one side may be directly connected to the conveying arm 220.

[0085] Figure 5 and 6 An example of the stamp 232 is shown. The stamp 232 may be made of an elastic body having a predetermined elasticity so as not to apply an impact when in contact with the LED 140. For example, the stamp 232 may be made of rubber or polymerized organic silicon (eg, PDMS (polydimethylsiloxane)), but is not limited thereto. Figure 6 As shown, the stamp 232 may include a body 234 and a detachable unit 235 , and the detachable unit 235 may have a protrusion shape protruding from one surface of the body 234 .

[0086] The stamp 232 may have one or more detachable units 235 on one surface. The detachable unit 235 may have a cylindrical shape, a conical cylindrical shape, or a polygonal cylindrical shape, and the one or more detachable units 235 may correspond to the upper surface of the LED 140. The detachable unit 235 may be configured to be detachably attached to the LED 140 depending on whether the internal structure is expanded.

[0087] The conveying arm 220 is connected to the head 230, and moves the head 230 three-dimensionally under the control of the controller 202. The controller 202 transmits a control signal to the pick-up unit 210 so that the pick-up unit 210 individually lifts or puts down each of the plurality of LEDs 140. For example, the controller 202 may control whether to lift and / or put down the corresponding LED 140 by transmitting a predetermined signal (e.g., voltage, current) to a specific detachable unit 235. The controller 202 may determine how to hold or release a specific LED 140, and may transmit a corresponding signal to the detachable unit 235.

[0088] Figure 6 Detailed structure of the detachable unit 235 is shown. The detachable unit 235 may include a first electrode 251; a second electrode 252 spaced apart from and facing the first electrode 251; a variable portion 240 disposed between the first electrode 251 and the second electrode 252, which has a size, such as a volume, that can be changed by an electrical signal applied by the first electrode 251 and the second electrode 252; and an adhesive portion 260 configured to be detachably attached to at least one LED 140 among the plurality of LEDs 140. The first electrode 251 and / or the second electrode 252 may be made of a material having a variable shape.

[0089] A control signal is transmitted to each of the first electrode 251 and the second electrode 252. In the figure, an electrical signal is transmitted to the first electrode 251 and the second electrode 252. The size of the variable portion 240 can be adjusted by a control signal applied to the first electrode 251 and the second electrode 252. The variable portion 240 may be made of an electroactive polymer, and in this case, when a constant voltage / current is applied, the molecular arrangement of the electroactive polymer changes and expands and / or contracts to change its size. The degree of expansion and / or contraction of the electroactive polymer varies according to the intensity of the applied voltage / current, and therefore, the total height of the detachable unit 235 can be changed. The shape of the first electrode 251 and / or the second electrode 252 may change according to the expansion and / or contraction of the variable portion 240.

[0090] When there are a plurality of detachable units 235, the detachable units 235 may have heights different from each other by changing the electrical signal applied to each detachable unit 235, thereby changing the variable size of the variable portion 240. Therefore, when the LED 140 is lifted, the detachable unit 235 having the variable portion 240 that is more expanded contacts the LED 140 to lift the LED 140 from one substrate 10. In addition, when the LED 140 is lowered, the LED 140 attached to the detachable unit 235 having the variable portion 240 that is more expanded contacts the target substrate, so that only the corresponding LED 140 is mounted on the target substrate. In this case, the height variation of the detachable unit 235 may be greater than the height of the corresponding LED 140.

[0091] The variable portion 240 may include: a polymer having electrostrictive properties, such as PVDF (polyvinylidene fluoride) and / or P(VDF-TrFE) (poly(vinylidene fluoride-trifluoroethylene); a polymer having dielectric properties, such as PDMS (polydimethylsiloxane); and copolymers thereof. Alternatively, the polymer making up the variable portion 240 may include: an electroactive polymer including liquid crystal molecules, rubber molecules, and mesogen molecules; a liquid crystal elastomer and copolymers thereof.

[0092] The adhesive portion 260 is made of a material having adhesiveness and is in direct contact with the LED 140. The adhesive portion 260 is required to hold the LED 140 when transferring the LED 140 from one substrate 10 to another substrate while having a certain degree of adhesiveness. In addition, since the adhesive force of the adhesive portion 260 is less than the adhesive force applied by the point where the LED 140 is mounted in the target substrate, the LED 140 placed on the target substrate can remain there. The adhesive portion 260 can be made of a patternable photosensitive adhesive composition, for example, a material based on PDMS (polydimethylsiloxane), a polyimide resin precursor (polyamic acid), or a polyimide resin.

[0093] Figure 6 Each of the first electrode 251, the second electrode 252, and the variable portion 240 in the detachable unit 235 is shown to have a single shape. Alternatively, as described below, the first electrode 251 and / or the second electrode 252 includes two or more strip-shaped electrodes, and the variable portion 240 is provided to correspond to each strip-shaped electrode. In addition, the variable portion 240 provided to correspond to each strip-shaped electrode may be configured to expand or contract sequentially in a predetermined order.

[0094] In such a structure of the strip-shaped electrode and the variable part 240, the size of the variable part 240 can be variously changed even in one detachable unit 235. Therefore, the detachable unit 235 can more accurately perform the operation of lifting or lowering the LED 140. Some examples and operations of the detachable unit 235 including a plurality of strip-shaped electrodes and the variable part 240 will be described below.

[0095] Figure 7 is a schematic plan view illustrating a structure of a detachable unit according to an exemplary embodiment of the present disclosure. Figures 8 to 10 is a schematic cross-sectional view illustrating a process of attaching an LED through a detachable unit according to an exemplary embodiment of the present disclosure.

[0096] The detachable unit 235 according to an exemplary embodiment of the present disclosure includes a first electrode 251 and a variable portion 240, each of which includes a plurality of segments of a circular shape and / or a ring shape. Figures 7 to 10 In the exemplary embodiment shown, the first electrode 251 includes a plurality of strip electrodes 251-1, 251-2, and 251-3 having concentric circles or concentric ring shapes, and the strip electrodes 251-1, 251-2, and 251-3 are separated from each other. The first strip electrode 251-1 having a circular shape is located in the center, and the second strip electrode 251-2 and the third strip electrode 251-3 having a ring shape with a larger diameter are arranged on the outside of the first strip electrode 251-1. The adhesive portion 260 may be applied to one surface of each strip electrode (or a surface in contact with each strip electrode). The second electrode 252 has a single, non-separated shape.

[0097] An insulating layer 255 is provided between each strip electrode 251-1, 251-2, and 251-3 constituting the first electrode 251. Each detachable unit 235 may include a wire connected to each strip electrode 251-1, 251-2, and 251-3 so that a separate control signal can be transmitted to each strip electrode 251-1, 251-2, and 251-3.

[0098] As an example, when the LED 140 is lifted and then placed on the target substrate, as shown in FIG. Fig. 9 As shown, an electrical signal is applied only to the third strip electrode 251-3 disposed at the outermost portion of the strip electrodes, so that only the variable portion 240 corresponding to the third strip electrode 251-3 can be expanded. Fig.10 As shown, an electrical signal may be applied only to the second strip-shaped electrode 251 - 2 of the inner ring, so that only the variable portion 240 corresponding to the second strip-shaped electrode 251 - 2 may be expanded.

[0099] Therefore, a height difference "d" may occur between the expanded portion of the variable portion 240 and the non-expanded portion of the variable portion 240. Thus, when only a portion of the variable portion 240 becomes larger, only a corresponding portion of the detachable unit 235 contacts the LED 140, and the other portion of the detachable unit 235 is separated from the LED 140. Therefore, since the overall adhesive force between the detachable unit 235 and the LED 140 is weakened, the LED 140 may be more easily mounted on a target substrate.

[0100] As another exemplary embodiment, a control signal (expansion signal) is sequentially transmitted from the central circular first belt electrode 251-1 to the outer ring type second belt electrode 251-2 and the third belt electrode 251-3 to expand the variable portion 240. When the LEDs are dropped in this manner, the LEDs 140 are attached to the target substrate in the order from the LEDs 140 corresponding to the central detachable unit 235 to the LEDs 140 corresponding to the peripheral detachable units 235, so that the LEDs 140 can be accurately attached to the target point without deformation.

[0101] Fig.11 is a schematic plan view illustrating a structure of a detachable unit according to another exemplary embodiment of the present disclosure. Fig.12 is a schematic cross-sectional view showing the structure of a detachable unit according to another exemplary embodiment of the present disclosure. The detachable unit 335 according to this exemplary embodiment includes a first electrode 351, a second electrode 352, and a variable portion 340, each of which includes a plurality of segments. Fig.11 and 12 In the example of FIG. 3 , the first electrode 351 includes a plurality of strip-shaped electrodes extending along the first direction. Fig.11 , the first electrode 351 includes six strip electrodes, but the present disclosure is not limited thereto. Some of the plurality of strip electrodes constituting the first electrode 351 may have the same shape as the variable portion 340. For example, some of the plurality of strip electrodes constituting the first electrode 350 are formed in the same shape as the variable portion 340, and four circular portions are provided in one strip electrode, but is not limited thereto.

[0102] In addition, the second electrode 352 includes a plurality of strip-shaped electrodes extending and arranged along a second direction intersecting the first direction. Fig.11 The second electrode 352 includes four strip electrodes extending in a vertical direction, but the present disclosure is not limited thereto. The insulating layer 355 may be disposed between the strip electrodes of the first electrode 351 and between the strip electrodes of the second electrode 352 .

[0103] The variable portion 340 may be located at a point where any one of the plurality of strip-shaped electrodes constituting the first electrode 351 extending in the first direction intersects with any one of the plurality of strip-shaped electrodes constituting the second electrode 352 extending in the second direction. Fig.11 and 12 , a small circular variable portion 340 may be provided at each intersection between one strip-shaped electrode constituting the first electrode 351 and one strip-shaped electrode constituting the second electrode 352. In this way, if the variable portion 340 has a so-called point arrangement, a controller (not shown) may select only a specific variable portion 340 according to the size or shape of the LED 140 to expand and / or contract the selected variable portion 340. Therefore, the detachable unit 350 may handle LEDs 140 of various sizes and shapes.

[0104] Fig.13 is a schematic plan view illustrating a structure of a detachable unit according to still another exemplary embodiment of the present disclosure. Figures 14 to 17 is a schematic cross-sectional view showing a process of attaching an LED through a detachable unit according to an exemplary embodiment of the present disclosure. The detachable unit 435 according to the third embodiment of the present disclosure includes a first electrode 451 and a variable portion 440, each of the first electrodes 451 including a plurality of circular and / or annular band electrodes 451-1, 451-2, and 451-3. Figures 13 to 17 In the embodiment of the present invention, the first electrode 451 includes a plurality of strip electrodes 451-1, 451-2 and 451-3 formed in concentric circles or concentric rings, and each of the strip electrodes 451-1, 451-2 and 451-3 is electrically connected to each other. A circular first strip electrode 451-1 is formed in the center, and a second strip electrode 451-2 and a third strip electrode 451-3 with gradually increasing diameters are arranged outside the first strip electrode 451-1. The adhesive portion 460 may be applied to one surface of each strip electrode constituting the first electrode 451 (or a surface in contact with each strip electrode). The second electrode 452 has a single, non-separated shape.

[0105] The insulating layer 455 may be provided between each of the strip-shaped electrodes 451-1, 451-2, and 451-3 constituting the first electrode 451. Figures 7 to 10Unlike the embodiment in, the detachable unit 435 includes wires connected to all the strip electrodes 451-1, 451-2 and 451-3 constituting the first electrode 451, so that a control signal can be transmitted to each of the strip electrodes 451-1, 451-2 and 451-3.

[0106] Each of the strip electrodes 451-1, 451-2, and 451-3 constituting the first electrode 451 may have different thicknesses from each other. For example, the central strip electrode 451-1 among the strip electrodes constituting the first electrode 451 may be the thickest, and the variable portion 440-1 corresponding to the central strip electrode 451-1 may be the thinnest. With this configuration, when an electrical signal is applied, the first strip electrode 451-1 located at the center has the highest current density, and the corresponding first variable portion 440-1 is the thinnest, and therefore, the first variable portion 440-1 corresponding to the first strip electrode 451-1 located at the center expands and / or contracts first compared to the other variable portions 440-2 and 440-3 corresponding to the other strip electrodes 451-1 and 451-2.

[0107] Then, the outer ring-shaped second strip electrode 451-1 and the third strip electrode 451-3 and the corresponding second variable part 440-2 and the third variable part 440-3 gradually expand and / or contract. As described above, when the sizes of the variable parts 440-1, 440-2 and 440-3 increase sequentially from the center to the outside, the LED 140 is separated from the adhesive part 460 in the same direction, so that the LED 140 can be installed in an appropriate position without deformation and rotation. Therefore, according to this embodiment, the accuracy of LED transfer can be improved.

[0108] Compared with the conventional conveying device, the LED conveying device can selectively transfer the LEDs and improve the transfer accuracy of the LEDs, which can improve the productivity of the LED display device.

[0109] Although the embodiments of the present disclosure have been described in detail with reference to the accompanying drawings, the present disclosure is not necessarily limited to those embodiments, and various modifications may be made within the scope of the present disclosure without departing from the technical spirit of the present disclosure. Therefore, the embodiments disclosed in the specification are used to explain rather than limit the technical spirit of the present disclosure, and the scope of the technical spirit of the present disclosure is not limited by those embodiments. Each feature of the various embodiments of the present disclosure may be partially or completely associated or combined with each other, and may be interlocked and driven differently by those skilled in the art, and each embodiment may be implemented independently of each other or together in a related relationship. The scope of the present disclosure should be interpreted by the attached claims, and all technical concepts within the scope equivalent thereto should be interpreted as included within the scope of the present disclosure.

Claims

1. A light emitting diode delivery device, include: a picking unit configured to lift at least a portion of the plurality of light emitting diodes disposed on the first substrate by a received control signal, and to place selected light emitting diodes among the lifted light emitting diodes onto the second substrate; as well as a controller configured to transmit the control signal to the picking unit so that the picking unit individually lifts or puts down each of the plurality of light emitting diodes, wherein the pickup unit comprises a head, the head comprising a plurality of detachable units configured to contact each of the plurality of light emitting diodes, Wherein, each of the plurality of detachable units comprises: a first electrode; a second electrode spaced apart from and facing the first electrode; a variable portion disposed between the first electrode and the second electrode, the variable portion having a size changeable by an electrical signal applied by the first electrode and the second electrode; and An adhesive portion is disposed on the first electrode, the adhesive portion being configured to be detachably attached to at least one of the plurality of light emitting diodes according to a size change of the variable portion.

2. The light emitting diode conveying device according to claim 1, in, The head includes a plate and a stamp, the plate being connected to a transport arm configured to move the head, wherein one surface of the stamp is configured to be in contact with the plate, and the detachable unit is protrudingly arranged on the other surface of the stamp.

3. The light emitting diode conveying device according to claim 2, in, The stamp includes an elastomer.

4. The light emitting diode conveying device according to claim 1, in, The first electrode includes a plurality of strip-shaped electrodes separated from each other, and a plurality of variable portions are arranged corresponding to the plurality of strip-shaped electrodes.

5. The light emitting diode conveying device according to claim 4, in, The plurality of variable portions are configured to expand or contract in a predetermined order.

6. The light emitting diode conveying device according to claim 4, in, The first electrode includes a plurality of strip-shaped electrodes having concentric circles or concentric ring shapes.

7. The light emitting diode conveying device according to claim 4, in, The detachable unit includes a plurality of conductive lines respectively connected to the plurality of strip-shaped electrodes to transmit an individual control signal to each of the plurality of strip-shaped electrodes.

8. The light emitting diode conveying device according to claim 4, in, The first electrode includes a plurality of strip-shaped electrodes extending along a first direction, and the second electrode includes a plurality of strip-shaped electrodes extending along a second direction intersecting the first direction.

9. The light emitting diode conveying device according to claim 8, in, Each of the plurality of variable portions is located at a position where any one of the plurality of strip-shaped electrodes extending in the first direction intersects with any one of the plurality of strip-shaped electrodes extending in the second direction.

10. The light emitting diode conveying device according to claim 1, in, The first electrode includes a plurality of strip-shaped electrodes having concentric circular or concentric annular shapes, and the plurality of strip-shaped electrodes are electrically connected to each other to transmit one control signal to each of the plurality of strip-shaped electrodes.

11. The light emitting diode conveying device according to claim 10, in, The plurality of strip-shaped electrodes have different thicknesses from each other.

12. The light emitting diode conveying device according to claim 11, in, A central strip electrode among the plurality of strip electrodes is the thickest.

13. The light emitting diode delivery device according to claim 12, in, The thickness of each of the plurality of strip-shaped electrodes decreases sequentially from the center to the periphery.

14. The light emitting diode delivery device according to claim 13, in, The variable portion provided corresponding to the central strip-shaped electrode expands or contracts before the variable portions corresponding to the other strip-shaped electrodes expand or contract.

15. The light emitting diode delivery device according to claim 1, in, The variable portion includes a polymer selected from the group consisting of an electroactive polymer, a liquid crystal elastomer, and copolymers thereof.

16. The light emitting diode delivery device according to claim 1, in, The variable portion includes a polymer selected from the group consisting of PVDF (polyvinylidene fluoride), P(VDF-TrFE) (poly(vinylidene fluoride-co-trifluoroethylene)), PDMS (polydimethylsiloxane) and copolymers thereof.

17. The light emitting diode delivery device according to claim 1, in, The adhesive part includes a polymer selected from the group consisting of PDMS (polydimethylsiloxane), polyamic acid, and a combination thereof.

18. The light emitting diode delivery device according to claim 1, in, The plurality of detachable units have heights different from each other by changing an electrical signal applied to each of the plurality of detachable units.

Images