Redundant pixel architecture in ILED displays
Described herein are ILED displays including redundancy in micro-light emitting diode (micro-LED) dies and methods of manufacturing the ILED displays. A micro-LED die emits light of a particular wavelength. The redundancy is added during manufacturing if defective micro-LED dies are identified. Additional micro-LED dies are included in inoperable sub-pixel assemblies to repair the inoperable sub-pixel assemblies that are identified to include defective micro-LED dies. An ILED display therefore includes at least one repaired sub-pixel assembly that includes two defective micro-LED dies and an operable micro-LED die that are coupled to separate branches of a current path from a current source.
1. A method for manufacturing a display device comprising sub-pixel assemblies, the method comprising:
placing a primary micro-light emitting diode (micro-LED) in each of the sub-pixel assemblies to create first sub-pixel assemblies;
identifying second sub-pixel assemblies among the first sub-pixel assemblies, the primary micro-LED of each second sub-pixel assembly identified as being defective by at least supplying current via a switch;
responsive to identifying the second sub-pixel assemblies;
turning off the switch to disconnect supply of the current to the primary micro-LED of each second sub-pixel assembly; and
placing a first replacement micro-LED in each of the second sub-pixel assemblies;
identifying third sub-pixel assemblies among the second sub-pixel assemblies, the primary micro-LED and the first replacement micro-LED of each third sub-pixel assembly being defective;
responsive to identifying the third sub-pixel assemblies:
physically severing a current path to the primary micro-LED and the first replacement micro-LED in each of the third sub-pixel assemblies, and
placing a second replacement micro-LED in each of the third sub-pixel assemblies.
2. The method of claim 1 , wherein the current is supplied by a driving circuitry.
3. The method of claim 2 , wherein placing the primary micro-LED comprises coupling the primary micro-LED to a first terminal of the switch.
4. The method of claim 3 , wherein placing the first replacement micro-LED comprises coupling the first replacement micro-LED to a second terminal of the switch.
5. The method of claim 2 , wherein physically severing a current path to the primary micro-LED and the first replacement micro-LED comprises creating a laser cut along the current path between the driving circuitry and the first replacement micro-LED.
6. The method of claim 2 , wherein placing the second replacement micro-LED comprises coupling the second replacement micro-LED to the driving circuitry.
7. The method of claim 2 , wherein identifying the second sub-pixel assemblies further comprises:
measuring an intensity of light emitted by each of the first sub-pixel assemblies, and
identifying one or more of the first sub-pixel assemblies emitting light having the intensity lower than a threshold intensity as the second sub-pixel assemblies.
8. The method of claim 2 , further comprising:
programming a memory element coupled to the switch in each of the second sub-pixel to turn off the switch.
9. The method of claim 1 , further comprising storing a location of each identified second sub-pixel assembly.
10. The method of claim 1 , wherein identifying the third sub-pixel assemblies comprises regulating a driving circuitry to supply the current to the first replacement micro-LED in each of the second sub-pixel assemblies.
11. The method of claim 10 , wherein identifying the third sub-pixel assemblies further comprises:
measuring an intensity of light emitted by each of the second sub-pixel assemblies, and
identifying one or more of the second sub-pixel assemblies emitting light having the intensity lower than a threshold intensity as the third sub-pixel assemblies.
12. A display device, comprising:
a first repaired sub-pixel assembly comprising:
a defective micro-light emitting diode (micro-LED) coupled to a first current source,
a first operable micro-LED connected to the first current source, and
a first switch coupled between the first operable micro-LED and the defective LED, the first switch configured to be turned off to disconnect the defective micro-LED from the first current source; and
a second repaired sub-pixel assembly comprising:
two defective micro-LEDs connected to a branch of a current path physically severed from a second current source, the branch of the current path connected to a third current source separate from the second current source, and
a second operable micro-LED connected to another branch of the current path connected to the second current source.
13. The display device of claim 12 , wherein the second repaired sub-pixel assembly comprises a laser cut point severing the second current source from the two defective micro-LEDs.
14. The display device of claim 12 , wherein the first repaired sub-pixel assembly comprises a second switch controlled by a control signal to turn on or turn off the first switch.
15. The display device of claim 12 , further comprising: an unrepaired sub-pixel assembly comprising:
a third operable micro-LED, and
a second switch coupled between the third operable micro-LED and the third current source, the second switch configured to connect the third operable micro-LED to the third current source.
16. The display device of claim 15 , wherein a first control signal to control the first switch is reverse of a second control signal to control the second switch.
17. The display device of claim 15 , wherein the first repaired sub-pixel assembly comprises a first memory element to control the first switch to turn on or off, and the unrepaired sub-pixel assembly comprises a second memory element to control the second switch to turn on or off.
18. The display device of claim 17 , wherein the each of the first memory element and the second memory element comprises a capacitor and a bias pad coupled to the capacitor.
19. The display device of claim 17 , wherein the first memory element stores a first bias charge, and the second memory element stores a second bias charge that is reverse of the first bias charge.
20. A display device made by a method comprising:
placing a primary micro-light emitting diode (micro-LED) in each of a plurality of sub-pixel assemblies to create first sub-pixel assemblies;
identifying second sub-pixel assemblies among the first sub-pixel assemblies, the primary micro-LED of each second sub-pixel assembly identified as being defective by at least supplying current via a switch;
responsive to identifying the second sub-pixel assemblies:
turning off the switch to disconnect supply of the current to the primary micro-LED of each second sub-pixel assembly, and
placing a first replacement micro-LED in each of the second sub-pixel assemblies;
identifying third sub-pixel assemblies among the second sub-pixel assemblies, the primary micro-LED and the first replacement micro-LED of each third sub-pixel assembly being defective;
responsive to identifying the third sub-pixel assemblies:
physically severing a current path to the primary micro-LED and the first replacement micro-LED in each of the third sub-pixel assemblies, and
placing a second replacement micro-LED in each of the third sub-pixel assemblies.