Transfer substrate, method of fabricating micro light emitting diode display substrate, and micro light emitting diode display substrate

Patent metadata

Field	Value
Publication number	US-11289537-B2
Application number	US-201916483734-A
Country	US
Kind code	B2
Filing date	Feb 12, 2019
Priority date	Sep 27, 2018
Publication date	Mar 29, 2022
Grant date	Mar 29, 2022

Abstract

A transfer substrate for transferring an array of a plurality of micro light emitting diodes (micro LEDs) onto a target substrate. The transfer substrate includes a base substrate and an array of a plurality of electroactive actuators. A respective one of the plurality of electroactive actuators includes a ring-shaped frame structure substantially surrounding a central opening, the ring-shaped frame structure made of an electroactive material. The ring-shaped frame structure is configured to undergo a reversible deformation between a first state and a second state upon a change in an electric field applied on the ring-shaped frame structure. A distance between two positions on an inner wall of the ring-shaped frame structure and across the central opening having a first value in the first state and a second value in the second state. The first value is greater than the second value.

First claim

What is claimed is:

1. A transfer substrate for transferring an array of a plurality of micro light emitting diodes (micro LEDs) onto a target substrate, comprising:
a base substrate; and
an array of a plurality of electroactive actuators;
wherein a respective one of the plurality of electroactive actuators comprises a ring-shaped frame structure substantially surrounding a central opening, the ring-shaped frame structure made of an electroactive material;
the ring-shaped frame structure is configured to undergo a reversible deformation between a first state and a second state upon a change in an electric field applied on the ring-shaped frame structure, a distance between two positions on an inner wall of the ring-shaped frame structure and across the central opening having a first value in the first state and a second value in the second state, the first value being greater than the second value;
a respective one of the plurality of electroactive actuators further comprises a controlling electrode;
the controlling electrode comprises a first controlling sub-electrode on a first side of the ring-shaped frame structure of the respective one of the plurality of electroactive actuators, and a second controlling sub-electrode on a second side of the ring-shaped frame structure of the respective one of the plurality of electroactive actuators;
a same row of the array of the plurality of electroactive actuators shares a same integral first controlling sub-electrode along a row direction of the array of the plurality of electroactive actuators; and
the same row of the array of the plurality of electroactive actuators shares a same integral second controlling sub-electrode along the row direction of the array of the plurality of electroactive actuators.

2. The transfer substrate of claim 1 , wherein the array of the plurality of electroactive actuators has a pattern substantially the same as a pattern of the array of a plurality of micro LEDs;
the central opening in the first state has a size greater than a size of a respective one of the plurality of micro LEDs, and the respective one of the plurality of micro LEDs being freely removable from the central opening in the first state; and
the central opening in the second state has a size equal to or less than the size of the respective one of the plurality of micro LEDs, and the ring-shaped frame structure is configured to secure the respective one of the plurality of micro LEDs therein.

3. The transfer substrate of claim 1 , wherein the ring-shaped frame structure has a closed ring shape.

4. The transfer substrate of claim 1 , wherein the electroactive material comprises a material selected from a group consisting of zinc oxide, lead magnesium niobate, lead magnesium niobate-lead titanate, lead lanthanum zirconate titanate, and lead barium zirconate titanate.

5. The transfer substrate of claim 1 , wherein a height of the ring-shaped frame structure along a direction perpendicular to a main surface of the base substrate is equal to or greater than one half of a height of a respective one of the plurality of micro LEDs to be transferred.

6. The transfer substrate of claim 1 , wherein a maximum width of the central opening between two positions on an inner wall of the ring-shaped frame structure is in a range of approximately 1 μm to approximately 100 μm; and
a thickness of a wall of the ring-shaped frame structure is in a range of approximately 1 μm to approximately 100 μm.

7. The transfer substrate of claim 1 , wherein an electric field is not applied to the ring-shaped frame structure in the first state;
upon application of an electric field on the ring-shaped frame structure, a wall of the ring-shaped frame structure is configured to expand toward a center of the central opening to reduce the distance between two positions on the inner wall of the ring-shaped frame structure from the first value to the second value; and
upon removal of the electric field on the ring-shaped frame structure, the wall of the ring-shaped frame structure is configured to withdraw away from the center of the central opening to increase the distance between two positions on an inner wall of the ring-shaped frame structure from the second value to the first value.

8. A transfer substrate for transferring an array of a plurality of micro light emitting diodes (micro LEDs) onto a target substrate, comprising:
a base substrate; and
an array of a plurality of electroactive actuators;
wherein a respective one of the plurality of electroactive actuators comprises a ring-shaped frame structure substantially surrounding a central opening, the ring-shaped frame structure made of an electroactive material;
the ring-shaped frame structure is configured to undergo a reversible deformation between a first state and a second state upon a change in an electric field applied on the ring-shaped frame structure, a distance between two positions on an inner wall of the ring-shaped frame structure and across the central opening having a first value in the first state and a second value in the second state, the first value being greater than the second value;
a respective one of the plurality of electroactive actuators further comprises a controlling electrode;
the controlling electrode comprises a first controlling sub-electrode on a first side of the ring-shaped frame structure of the respective one of the plurality of electroactive actuators, and a second controlling sub-electrode on a second side of the ring-shaped frame structure of the respective one of the plurality of electroactive actuators;
the controlling electrode and the ring-shaped frame structure are on a same layer;
the first controlling sub-electrode is on a side of a wall of the ring-shaped frame structure away from a center of the central opening;
the second controlling sub-electrode is on a side of the wall of the ring-shaped frame structure away from the center of the central opening; and
the first side is substantially opposite to the second side.

9. The transfer substrate of claim 8 , wherein the array of the plurality of electroactive actuators has a pattern substantially the same as a pattern of the array of a plurality of micro LEDs;
the central opening in the first state has a size greater than a size of a respective one of the plurality of micro LEDs, and the respective one of the plurality of micro LEDs being freely removable from the central opening in the first state; and
the central opening in the second state has a size equal to or less than the size of the respective one of the plurality of micro LEDs, and the ring-shaped frame structure is configured to secure the respective one of the plurality of micro LEDs therein.

10. The transfer substrate of claim 8 , wherein the ring-shaped frame structure has a closed ring shape.

11. The transfer substrate of claim 8 , wherein the electroactive material comprises a material selected from a group consisting of zinc oxide, lead magnesium niobate, lead magnesium niobate-lead titanate, lead lanthanum zirconate titanate, and lead barium zirconate titanate.

12. The transfer substrate of claim 8 , wherein a height of the ring-shaped frame structure along a direction perpendicular to a main surface of the base substrate is equal to or greater than one half of a height of a respective one of the plurality of micro LEDs to be transferred.

13. The transfer substrate of claim 8 , wherein a maximum width of the central opening between two positions on an inner wall of the ring-shaped frame structure is in a range of approximately 1 μm to approximately 100 μm; and
a thickness of a wall of the ring-shaped frame structure i

Assignees

• Beijing Boe Optoelectronics Tech Co Ltd
• Boe Technology Group Co Ltd

Inventors

• Fang Liyu
• Sun Lingyu
• Du Jingjun
• Liang Fei
• Hou Tingxiu

Classifications

• H10P72/0446

  Apparatus for mounting on conductive members, e.g. leadframes or conductors on insulating substrates · CPC title

• H10W90/00

  Package configurations · CPC title

• H10D86/60

  wherein the TFTs are in active matrices · CPC title

• H10D86/411

  characterised by materials, geometry or structure of the substrates · CPC title

• H10D86/021

  of multiple TFTs · CPC title