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MicroLED

Samsung: the 146" TV, aka the Wall , showcased in CES2019


MicroLED shares a number of traits with OLED technology, making comparisons a little easier than LCD vs OLED debates. For starters, both have LED in their name, meaning that they’re both constructed from light emitting diodes. The two are “self-emitting” technologies, so each red, green, and blue sub-pixel produces its own light, unlike LCD, which requires a dedicated backlight. 




architecture

TFT vs OLED vs MicroLED






Where microLED differs from OLED is in the makeup of the LED materials. The O in OLED stands for organic and refers to the organic materials used in light producing part of the pixel stack. MicroLED technology changes this to an inorganic Gallium Nitride (GaN) material, which is typically found in regular LED lighting. This switch also reduces the need for a polarizing and encapsulation layer, making panels thinner. As a result, MicroLED components are tiny, hence the name, measuring less than 100 µm. That’s less than the width of a human hair.




Pros and Cons

pros:

wider gamut

higher intensity

lower power consumption
longer lifetime

cons:

manufacturing cost

how to mass transfer and bond million of LEDs over to the control circuit panel. One potential solution sees the LEDs picked and placed into a larger array, to then be soldered to complete a display. The issue is that the accuracy of current pick and place manufacturing is ±34µm, which doesn’t meet the ±1.5µm accuracy requirements to place these tiny LED components.

Flip-chip technology isn’t without its problems either, even though it is currently the favored method for producing microLED panels. In this method, a wafer carrying the light emitting layer is flip-bonded onto the driver circuitry and then soldered. Unfortunately, this method is done one substrate at a time is therefore very slow. Investments are being made to improve yields, which suffer due to thermal mismatching and those pesky alignment accuracy issues.


Where microLED differs from OLED is in the makeup of the LED materials. The O in OLED stands for organic and refers to the organic materials used in light producing part of the pixel stack. MicroLED technology changes this to an inorganic Gallium Nitride (GaN) material, which is typically found in regular LED lighting. This switch also reduces the need for a polarizing and encapsulation layer, making panels thinner. As a result, MicroLED components are tiny, hence the name, measuring less than 100 µm. That’s less than the width of a human hair.

JBD is developing a fabrication approach based on monolithic hybrid integration technology that should be better suited to small pitch LED for very high-density displays. JBD’s manufacturing method that bonds the LED to IC layer and then strips away the bonding material using a familiar semiconductor fabrication process, facilitating more cost-effective development. Taiwan’s PlayNitride and  AUO are also working on LED chip technologies for this style of manufacturing, and talks have been taking place between them and Apple and Samsung.



Technnical players:
PlayNitride
AUO
TSMC
Radiant

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