Emissive element harvest
A method is provided for the selective harvest of microLED devices from a carrier substrate. Defect regions are predetermined that include a plurality of adjacent defective microLED devices on a carrier substrate. A solvent-resistant binding material is formed overlying the predetermined defect regions and exposed adhesive is dissolved with an adhesive dissolving solvent. Non-defective microLED devices located outside the predetermined defect regions are separated from the carrier substrate while adhesive attachment is maintained between the microLED devices inside the predetermined defect regions and the carrier substrate. Methods are also provided for the dispersal of microLED devices on an emissive display panel by initially optically measuring a suspension of microLEDs to determine suspension homogeneity and calculate the number of microLEDs per unit volume. If the number of harvested microLED devices in the suspension is known, a calculation can be made of the number of microLED devices per unit of suspension volume.
1. A system for selectively segregating regions of a micro light emitting diode (microLED) carrier substrate, the system comprising:
a controller having an output to supply a first map of predetermined defect regions in the carrier substrate;
a printer having an input to accept the first map and a nozzle to apply a solvent-resistant binding material to selected regions of the carrier substrate in response to the first map; and;
wherein microLEDs in the selected regions remain attached to the carrier substrate despite exposure to an adhesive dissolving solvent.
2. The system of claim 1 where the solvent-resistant binding material is selected from the group consisting of SU-8, epoxy resin, polyethylene terephthalate (PET), acrylonitrile butadiene styrene (ABS), or polyimide.
3. The system of claim 1 further comprising:
an inspection subsystem having an optical input and an output connected to the controller identifying non-predetermined defective microLED device regions on the carrier substrate; and,
wherein the printer accepts a second map of the non-predetermined defective microLED device regions from the controller and applies the solvent-resistant binding material to detected defective microLED device regions in response to the second map.