Active matrix (AM) mini-LED backlight units (BLUs) based on amorphous silicon (a-Si) thin-film transistor (TFT) on a glass substrate for 75-inch 8K liquid crystal displays (LCDs) are developed, with each consisting of 5184 local dimming (LD) zones. The 75-inch 8K LCDs perform a high dynamic contrast ratio of 1,000,000:1 and high typical brightness of more than 1000 nits with 10% capable screen area. In addition, the LCDs show an excellent high dynamic range (HDR) and a real black state, which are comparable to that of other high-end displays (dual cells and organic light-emitting diode displays [OLEDs]). Also, the mini-LED BLUs feature a low fabrication cost.

We have successfully prepared GaN based high electron mobility transistors (HEMTs) on metallic substrates transferred from silicon substrates by electroplating technique. GaN HEMTs on Cu substrates are demonstrated to basically have the same good electric characteristics as the chips on Si substrates. Furthermore, the better heat dissipation of HEMTs on Cu substrates compared to HEMTs on Si substrates is clearly observed by thermoreflectance imaging, showing the promising potential for very high-power and high-temperature operation. This work shows the outstanding ability of HEMT chips on Cu substrates for solving the self-heating effect with the advantages of process simplicity, high yield, and low production requirement.

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