Driving backplane, transfer method for light-emitting diode chip, display apparatus

Patent metadata

Field	Value
Publication number	US-12368144-B2
Application number	US-202117922139-A
Country	US
Kind code	B2
Filing date	May 14, 2021
Priority date	May 25, 2020
Publication date	Jul 22, 2025
Grant date	Jul 22, 2025

Abstract

A driving backplane, a transfer method for a light-emitting diode chip ( 21 ), and a display apparatus. The driving backplane comprises: a base substrate ( 10 ), a driving circuit, a plurality of electromagnetic structures ( 13 ), and a plurality of contact electrodes ( 12 ). The plurality of electromagnetic structures ( 13 ) in the driving backplane are symmetrically arranged relative to a first straight line (L 1 ) and a second straight line (L 2 ). A current signal can be applied to each electromagnetic structure ( 13 ) by means of the driving circuit. Stress generated by a transfer carrier plate ( 20 ) according to the magnetic force of each electromagnetic structure ( 13 ) moves the transfer carrier plate ( 20 ). When the transfer carrier plate ( 20 ) is stress balanced in each direction parallel to the surface of the transfer carrier plate ( 20 ), the light-emitting diode chip ( 21 ) is precisely aligned to corresponding contact electrodes ( 12 ).

First claim

What is claimed is:

1. A driving backplane, comprising:
a base substrate;
a plurality of contact electrodes on a side of the base substrate, wherein the plurality of contact electrodes are distributed in array in a first direction and a second direction and define a display region, and the first direction intersects with the second direction;
a plurality of electromagnetic structures on a side of the base substrate, wherein the plurality of electromagnetic structures are symmetrically arranged relative to a first straight line and a second straight line, the first straight line is a straight line where a center line of the display region in the first direction is located, and the second straight line is a straight line where a center line of the display region in the second direction is located; and
a driving circuit between the base substrate and a layer where the contact electrodes are located, wherein the driving circuit is electrically connected to each of the electromagnetic structures and configured to supply a current signal to the electromagnetic structure during an alignment process of transferring a light-emitting diode chip so that the electromagnetic structure generates a magnetic field having the same magnetism as the light-emitting diode chip, and stop supplying the current signal to the electromagnetic structure after alignment is completed, so that the light-emitting diode chip makes contact with the contact electrodes corresponding to the light-emitting diode chip under an action of a pressure.

2. The driving backplane according to claim 1 , wherein in at least part of the display region, at least four of the electromagnetic structures symmetrically arranged relative to each of the contact electrodes are arranged around the contact electrode.

3. The driving backplane according to claim 2 , wherein four of the electromagnetic structures symmetrically arranged relative to each of the contact electrodes are arranged around each of the contact electrode.

4. The driving backplane according to claim 1 , wherein the driving backplane includes at least four alignment regions in an edge region and symmetrically arranged relative to the first straight line and the second straight line; the edge region is a region beyond the display region; and
the electromagnetic structures are arranged in all the alignment regions.

5. The driving backplane according to claim 1 , wherein each of the electromagnetic structures comprises: a conductive column and a conductive coil surrounding the conductive column; and
an extension direction of the conductive column is perpendicular to a surface of the driving backplane.

6. The driving backplane according to claim 5 , wherein the conductive coil comprises: a plurality of sub-coils stacked;
each of the electromagnetic structure further comprises: an insulation layer between sub-coils which are adjacent to each other; and
the sub-coils which are adjacent to each other are electrically connected with each other through a through hole in the insulation layer.

7. The driving backplane according to claim 6 , wherein the driving circuit comprises: a thin film transistor; and
at least part of the sub-coils of the conductive coil is in a same layer as a source electrode and a gate electrode of the thin film transistor.

8. A display apparatus, comprising: the driving backplane according to claim 1 , and the plurality of light-emitting diode chips bound to the plurality of contact electrodes of the driving backplane.

9. A transfer method for a light-emitting diode chip, comprising:
providing a transfer carrier plate; wherein a surface of the transfer carrier plate has a plurality of light-emitting diode chips, each of the light-emitting diode chips comprises two extraction electrodes, and the two extraction electrodes are on a side of the light-emitting diode chip facing away from the transfer carrier plate;
magnetizing the two extraction electrodes of the light-emitting diode chip so that magnetism of all the extraction electrodes is the same;
moving the transfer carrier plate onto the driving backplane according to claim 1 , wherein the surface of the transfer carrier plate having the plurality of light-emitting diode chips is opposite to a surface of the driving backplane having the contact electrodes;
supplying a current signal to each of the electromagnetic structures of the driving backplane after performing a first alignment between the transfer carrier plate and the driving backplane by using alignment marks, so that the electromagnetic structure generates a magnetic field having a same magnetism as the extraction electrodes;
applying a pressure to the transfer carrier plate, so that the transfer carrier plate approaches the driving backplane and a certain distance is between the transfer carrier plate and the driving backplane;
moving the transfer carrier plate according to stress generated by a detected magnetic force of the electromagnetic structures for the transfer carrier plate;
stopping moving the transfer carrier plate when the transfer carrier plate is under stress balance in each direction parallel to the surface of the transfer carrier plate, so that a second alignment between the transfer carrier plate and the driving backplane is completed; and
stopping supplying the current signal to the electromagnetic structure, so that the magnetic field of the electromagnetic structure disappears;
performing heating and press fit on the transfer carrier plate and the driving backplane so that the extraction electrodes are fixedly connected to the corresponding contact electrodes; and
separating the transfer carrier plate from the light-emitting diode chips and removing the transfer carrier plate.

10. The transfer method according to claim 9 , wherein the surface of the transfer carrier plate has a pyrolytic adhesive; the plurality of light-emitting diode chips are glued to the transfer carrier plate through the pyrolytic adhesive; and
the separating the transfer carrier plate from the light-emitting diode chips comprises:
heating the transfer carrier plate to reduce viscosity of the pyrolytic adhesive so that the transfer carrier plate is separated from the light-emitting diode chips.

11. The transfer method according to claim 9 , wherein the surface of the transfer carrier plate has a photolytic adhesive; the plurality of light-emitting diode chips are glued to the transfer carrier plate through the photolytic adhesive; and
the separating the transfer carrier plate from the light-emitting diode chips comprises:
irradiating the photolytic adhesive by using a light ray within a set wavelength range to reduce viscosity of the photolytic adhesive so that the transfer carrier plate is separated from the light-emitting diode chips.

12. The transfer method according to claim 9 , wherein the providing a transfer carrier plate comprises:
forming multiple light-emitting diode chips on a wafer, wherein the extraction electrodes of each of the multiple light-emitting diode chips are on a side of the multiple light-emitting diode chips facing away from the wafer;
detecting each of the multiple light-emitting diode chips on the wafer;
moving the wafer onto a middle carrier plate, wherein a surface of the wafer having the multiple light-emitting diode chips faces the middle carrier plate, and light-emitting diode chips which are qualified after detection are transferred onto the middle carrier plate; and
transferring the light-emitting diode chips which are qualified on the middle carrier plate onto the transfer carrier plate so that the extraction electrodes of each of the light-emitting diode chips which are qualified are lo

Assignees

• Boe Technology Group Co Ltd

Inventors

• Lv Zhijun
• Zhang Feng
• Liu Wenqu
• Song Xiaoxin
• Cui Zhao
• Dong Liwen
• Meng Detian
• Wang Libo
• Hou Dongfei
• Zhang Lizhen

Classifications

• H10W90/00 Primary

  Package configurations · CPC title

• H10W72/0198

  batch processes · CPC title

• H10W72/9445

  Top-view layouts, e.g. mirror arrays · CPC title

• H10W72/07332

  Compression bonding, e.g. thermocompression bonding · CPC title

• H10W72/355

  of outermost layers of multilayered die-attach connectors, e.g. material of a coating · CPC title