Method for transferring light emitting elements, display panel, method for making display panel, and substrate

{
  "publication_number": "US11088182B2",
  "country": "US",
  "kind": "B2",
  "title": "Method for transferring light emitting elements, display panel, method for making display panel, and substrate",
  "abstract": "A method for transferring light emitting elements precisely during manufacture of display panels includes providing light emitting elements; providing a first electromagnetic plate defining magnetic adsorption positions; providing a receiving substrate defining receiving areas; energizing the first electromagnetic plate to magnetically adsorb one light emitting element at one adsorption position; facing the first electromagnetic plate to the receiving substrate; and transferring the light emitting elements to one receiving area of the receiving substrate.",
  "claims": [
    "1. A method for transferring light emitting elements, comprising: providing a plurality of light emitting elements, wherein a magnetic material layer is on an end of each of the plurality of light emitting elements; providing a first electromagnetic plate, wherein the first electromagnetic plate defines a plurality of adsorption positions, wherein each of the light emitting elements is magnetically positioned and attracted to a corresponding one of the adsorption positions when the first electromagnetic plate is energized; providing a receiving substrate, wherein providing the receiving substrate comprising comprises providing a base layer, forming an electromagnetic circuit layer on a side of the base layer, and forming a bonding layer on a side of the electromagnetic circuit layer away from the base layer, wherein the electromagnetic circuit layer comprises a coil, the bonding layer defines a plurality of receiving areas, each of the plurality of receiving areas is configured for receiving one of the plurality of light emitting elements; energizing the first electromagnetic plate to magnetically adsorbs one of the plurality of light emitting elements at the corresponding one of the adsorption positions; facing a surface of the first electromagnetic plate on which the plurality of light emitting elements are magnetically adsorbed to a surface of the receiving substrate defining the plurality of receiving areas; aligning the plurality of the light emitting elements with the plurality of the receiving areas one by one; and applying a current to the coil to form a magnetic field, and powering off the first electromagnetic plate so that each of the plurality of light emitting elements is detached from the first electromagnetic plate by the magnetic field and transferred to the corresponding one of the receiving areas on the receiving substrate.",
    "2. The method according to claim 1, wherein the coil comprises an annular portion, and the coil is arranged such that a plane in which the annular portion located is perpendicular to a thickness direction of the receiving substrate.",
    "3. The method for according to claim 1, further comprising: forming an insulating nonmagnetic material layer on a surface of the first electromagnetic plate; and defining a plurality of through holes, wherein the first electromagnetic plate is exposed to the insulating nonmagnetic material layer where the plurality of through holes are, wherein the plurality of through holes are the plurality of adsorption positions.",
    "4. The method according to claim 1, wherein forming the bonding layer further comprises forming a thin film transistor (TFT) array layer on a side of the electromagnetic circuit layer away from the base layer and forming a pixel defining layer on a side of the TFT array layer away from the base layer, wherein the pixel defining layer defines a plurality of contact holes, the TFT array layer is exposed where the plurality of contact holes are, the plurality of contact holes are the plurality of receiving areas.",
    "5. The method for according to claim 4, wherein forming the receiving substrate further comprises forming an insulating layer between the electromagnetic circuit layer and the TFT array layer.",
    "6. A method for making a display panel, comprising: providing a plurality of light emitting elements, wherein a magnetic material layer is on an end of each of the plurality of light emitting elements; providing a first electromagnetic plate, wherein the first electromagnetic plate defines a plurality of adsorption positions, each of the plurality of adsorption positions is capable of magnetically attracting one light emitting element on being energized; providing a receiving substrate, wherein providing the receiving substrate comprising comprises providing a base layer, forming an electromagnetic circuit layer on a side of the base layer, and forming a bonding layer on a side of the electromagnetic circuit layer away from the base layer, wherein the electromagnetic circuit layer comprises a coil, the bonding layer defines a plurality of receiving areas, each of the plurality of receiving areas is configured for receiving one of the plurality of light emitting elements; energizing the first electromagnetic plate to magnetically adsorb one of the plurality of light emitting elements at the corresponding one of the adsorption positions; facing a surface of the first electromagnetic plate on which the plurality of light emitting elements are magnetically adsorbed to a surface of the receiving substrate defining the plurality of receiving areas; aligning the plurality of the light emitting elements with the plurality of the receiving areas one by one; and applying a current to the coil to form a magnetic field, and powering off the first electromagnetic plate so that each of the plurality of light emitting elements is detached from the first electromagnetic plate by the magnetic field and transferred to the corresponding one of the receiving areas on the receiving substrate.",
    "7. The method according to claim 6, wherein the coil comprises an annular portion, and the coil is arranged such that a plane in which the annular portion located is perpendicular to a thickness direction of the receiving substrate.",
    "8. The method according to claim 6, wherein forming the bonding layer further comprises forming a thin film transistor (TFT) array layer on a side of the electromagnetic circuit layer away from the base layer and forming a pixel defining layer on a side of the TFT array layer away from the base layer, wherein the pixel defining layer defines a plurality of contact holes, the TFT array layer is exposed where the plurality of contact holes are, the plurality of contact holes are defined as the plurality of receiving areas.",
    "9. The method according to claim 8, wherein forming the receiving substrate further comprises forming an insulating layer between the electromagnetic circuit layer and the TFT array layer.",
    "10. The method according to claim 8, wherein forming the TFT array layer comprises forming a plurality of thin film transistors (TFTs), each of the plurality of light emitting elements having a first electrode and a second electrode, the first electrode of each of the plurality of light emitting elements is electrically connected with one of the plurality of TFTs.",
    "11. The method according to claim 10, after each of the plurality of light emitting elements is detached from the first electromagnetic plate by the magnetic field and transferred to a corresponding receiving area of the receiving substrate, the method further comprising forming a planarization layer on a side of the pixel defining layer away from the base layer, and the planarization layer fills a gap between adjacent two of the plurality of light emitting elements and exposes the second electrode of each of the plurality of light emitting elements.",
    "12. The method according to claim 11, further comprising forming a common electrode layer on a side of the planarization layer away from the pixel defining layer, wherein the common electrode layer is electrically connected to the second electrode of each of the plurality of light emitting elements.",
    "13. A substrate in a display panel, comprising: a base layer; an electromagnetic circuit layer on a side of the base layer, the electromagnetic circuit layer comprising a plurality of coils; and a thin film transistor (TFT) array layer on a side of the electromagnetic circuit layer away from the base layer; wherein the plurality of coils is spaced apart from each other, each of the plurality of coils comprises an annular portion and two connecting portions extending from ends of the annular portion, each of the plurality of coils is arranged such that a plane in which the annular portion located is perpendicular to a thickness direction of the base layer, a plurality of the annular portions extends to form a plurality of concentric circles, and inner diameters of the plurality of the annular portions sequentially increase in a direction away from the center of the plurality of concentric circles.",
    "14. The substrate in the display panel according to claim 13, further comprising an insulating layer between the electromagnetic circuit layer and the TFT array layer.",
    "15. The substrate in the display panel according to claim 13, further comprising a pixel defining layer on a side of the TFT array layer away from the base layer, wherein the pixel defining layer defines a plurality of contact holes, the TFT array layer is exposed where the plurality of contact holes are.",
    "16. A display panel comprising a substrate and a plurality of light emitting elements on the substrate, wherein the substrate comprises: a base layer; an electromagnetic circuit layer on a side of the base layer, the electromagnetic circuit layer comprising a plurality of coils; and a thin film transistor (TFT) array layer on a side of the electromagnetic circuit layer away from the base layer; wherein the plurality of light emitting elements is electrically connected to the TFT array layer, and a magnetic material layer is on an end of each of the plurality of light emitting elements; wherein the plurality of coils is spaced apart from each other, each of the plurality of coils comprises an annular portion and two connecting portions extending from ends of the annular portion, each of the plurality of coils is arranged such that a plane in which the annular portion located is perpendicular to a thickness direction of the base layer, a plurality of the annular portions extends to form a plurality of concentric circles, and inner diameters of the plurality of the annular portions sequentially increase in a direction away from the center of the plurality of concentric circles; wherein the electromagnetic circuit layer is configured to form a magnetic field to magnetically adsorb the magnetic material layer of each of the plurality of light emitting elements in a process of transferring the plurality of light emitting elements to the substrate."
  ],
  "description_excerpt": "The subject matter herein generally relates to display field, and particularly relates to a method for transferring light emitting elements, a display panel, a method for making the display panel, and a substrate.\n\nThe size of a light emitting element such as light emitting diode (LED) generally tends towards smaller size, as a result, transferring a large number of light emitting elements to a receiving substrate is challenging. Therefore, there is room for improvement in the art.\n\nImplementations of the present disclosure will now be described, by way of embodiment, with reference to the attached figures. FIG. 1 is a flow chart of a method for transferring light emitting elements. FIG. 2 is a cross-sectional view illustrating the light emitting elements during Block S 11 of the method as disclosed in FIG. 1. FIG. 3 is a cross-sectional view illustrating the first electromagnetic plate during Block S 12 of the method as disclosed in FIG. 1. FIG. 4 is a cross-sectional view illustrating the receiving substrate during Block S 13 of the method as disclosed in FIG. 1. FIG. 5 shows a receiving substrate of FIG. 4 made according to the method. FIG. 6 is an arrangement diagram of coils of the receiving substrate shown in FIG. 5. FIG. 7 is a schematic diagram of distribution of magnetic lines of force after the coils shown in FIG. 5 is energized. FIG. 8 shows projections of the electromagnetic unit and the receiving area of the receiving substrate shown in FIG. 4 according to an embodiment.",
  "cpc": [
    "H10P 72/3408",
    "B65G 47/92",
    "H01L 27/1248",
    "H01L 27/1259",
    "H10D 86/021",
    "H10D 86/451",
    "H10D 86/60",
    "H10H 20/01",
    "H10H 29/142",
    "H10P 72/3412",
    "H10P 72/74",
    "H10W 90/00"
  ],
  "ipc": [
    "B65G 47/92",
    "H01L 27/12"
  ],
  "assignees": [
    "CENTURY TECH SHENZHEN CORPORATION LIMITED"
  ],
  "inventors": [
    "CHEN PO-LIANG",
    "LIN YUNG-FU"
  ],
  "filing_date": "2019-11-13",
  "publication_date": "2021-08-10",
  "grant_date": "2021-08-10",
  "priority_date": "2019-07-05",
  "application_number": "US-201916681949-A",
  "family_id": "67924688",
  "citations": [
    "CN106571371A",
    "CN107808835A",
    "CN109378370A",
    "CN109755162A",
    "CN1967865A",
    "TW201626555A",
    "US2008303774A1",
    "US2014320759A1",
    "US2017104009A1",
    "US2019304818A1",
    "US8416174B2",
    "US9696768B2"
  ]
}