lasers - Page 3

Researchers at Zhejiang University developed a laser-driven programmable non-contact transfer printing technique that could be applicable to the transfer of Micro-LED chips. The researchers used an innovative design based on an active elastomeric micro-structured stamp with tunable adhesion.

The tunable adhesive used in this technique features cavities filled with air and encapsulated by a micro-patterned surface membrane, used in easily available sandpapers. The micro-patterned surface membrane can be inflated dynamically to control the interfacial adhesion by heating the air in cavities.

Laser equipment maker Coherent says that its customer have expressed a "reasonable amount of interest " in its Micro-LED solutions. The company is taking orders for R&D tools, but it says that mass production of Micro-LED displays is "still years away".

Coherent offers several laser-based tools used to produce Micro-LED displays, including Laser Lift-Off equipment (LLO) used to separate micro-LEDs from the sapphire wafer and Laser Induced Forward Transfer (LIFT) used to move micro-LEDs from the donor to substrate.

During a presentation at SID Displayweek 2018, laser developer Coherent showed a nice chart that summarizes the performance difference between LCDs, OLEDs and Micro-LED displays.

Coherent says that its lasers could be used in the pick-and-place process when making micro-LEDs. A laser lift-off process (LLO) removes the LED chips from the sapphire growth wafer (or any other carrier wafer) and a the laser-inducted forward-transfer (LIFT) process transfer selected dies from carrier to substrate in a high-precision way that can be massively parallel (over 25,000 dies per shot).