Selective Transfer of Light-Emitting Diodes onto a Flexible Substrate via Laser Lissajous Scanning.

As the light-emitting diode (LED) size gradually decreases, it is difficult to conventionally transfer an LED onto a donor substrate. In this paper, we propose a print transfer method that selectively transfers an LED onto a UV release tape, i.e., the donor substrate, via focused laser scanning with Lissajous patterns. We implemented an optical system based on focused laser scanning to perform selective transfer; this can adjust the scanning area immediately without changing the donor substrate size according to the LED size. Because the commercialized UV release tape is utilized as a donor substrate, the adhesion between the LED and donor substrate can be constantly maintained even after repeated experiments. In this study, several LEDs were transferred to a flexible printed circuit board-arranged in a circular and square shape to demonstrate a high degree of freedom of the system-and turned on.