Fully Operating MicroLED Arrays with Pixel Sizes as Small as 5 μm

Different LED pixel switching patterns obtained from 8 × 8 microLED array showing line (left), and full array with lower (middle) and higher (right) driving powers.

Institute of Semiconductor Technology (IHT) and the Laboratory for Emerging Nanometrology (LENA) at the Technische Universität Braunschweig, Braunschweig, Germany have produced and demonstrated the first fully operating microLED arrays with pixel sizes as small as 5 μm. The fabrication of 8 × 8 microLED arrays with separately addressable pixels includes multiple photolithography, etching, bonding, and other advanced chip processing steps, which are carried out in the IHT cleanroom.

The exceptionality and novelty of this technology locate on the miniaturization of the whole array down to 5 μm, which is considered as one of the smallest microLED array in the world with individually controllable pixels. This size is much smaller than a human hair. However, similar fabrication process can be used for producing bigger microLED arrays with up to 100 μm pixel size. Concomitant customized software allows easy control of light pattern, brightness, and modulation frequency. This microLED can be operated up to 2 MHz. These parameters play a role in the imaging process, and have to be controlled not to overexpose or burn a living cell. The optical properties of the microLEDs, such as radiance, angular intensity distribution, and total flux, have been measured using a goniometry system enabling further understanding of the devices and their subsequent improvement.

The 5 μm microLED array is currently being used for integration with the CMOS detector to build the Chipscope microscope, paving the way towards the chip-based superresolution microscopy.

Contact and further information:

Dr. Hutomo Suryo Wasisto,  Technische Universität Braunschweig, h.wasisto@tu-bs.de