So you admit that what you are describing isn’t microLED. Those LED walls aren’t pitched or sold as microLED and they aren’t even using individual microLED pixels because they are significantly higher power devices with higher luminosities.
And nobody is doing that.Really you are going to say a technique, that picks up microLEDs with static electricity, and places them where where they need to be, isn't analogous with standard Pick and Place machines?
All transfer techniques related to MicroLEDs are analogous to pick and place. MicroLEDs do not use patterned bulk chemical deposition to create emitters directly on the substrate. They all use prefabricated components (the LEDs) that are placed on a substrate in a specific location and orientation by some type of gripping device.
The processes are more analogous to film transfer processes than individualized pick and place. Pick and place is a specific process and has a very specific meaning and these processes aren’t it.
So what positions and orients the LED components on the film prior to transfer to the final substrate?
As far as I can tell, the difference is one of scale and type of gripper. MicroLED obviously won't/doesn't use actual pick and place machines since they're too coarse, but I haven't read anything that suggests that a similar machine that operates on a smaller scale isn't what is used.
I did some microCPV stuff in a previous life. I did not do transfer printing but have talked to people who have. One common method that I have described here is to take the wafer of devices you want transfer printed and apply a transfer tape. After that, you either singulate devices or remove the substrate. Then you stretch the film until you get the desired device pitch and the. You bond the whole thing in one go. It looks, feels, and tastes like a film transfer process and nothing like pick and place. Pick and place is not commercially viable (though to be fair, neither was CPV).
Only one of those you mentioned is pick and place and it was developed by a nothing company Apple bought for pocket change.
OK, now I understand what you meant by "dilating the film in x and y after substrate removal".
No, not really. MicroLED is very much at the micro scale, not the nano scale. Phone screens have pixel pitches in the 50-60µm range, so the LEDs subpixels for an equivalent microLED screen would still be over 10µm apart. A 1µm positional variance wouldn't be visible to the naked eye, so you could have oversized bonding pads to handle less than perfect precision.
Sure, but we're talking modern materials science for the film, probably aided by applied softening/stretching agents during the stretching process, done on precision stretching machines, not drawing on a rubber band with a sharpie and then stretching it and pressing it against your finger. It's plausible to be economical for this use, unlike pick and place. It'll still cost more than OLED, bit it isn't obvious it'll cost so much more that it isn't viable for any application.
Uh, what? Subpixels have never been grouped like that, from actual ink on paper processes, to CRTs, to LCDs and plasma and OLEDs. Why would microLED have strongly grouped, very uneven spacing instead of the even to only slightly uneven spacing we've had for ages?
This statement is false. Tons of work is going into mass transfer because the technology requires it in order to be commercially viable.
