In‐pixel temperature sensor for high‐luminance active matrix micro‐light‐emitting diode display using low‐temperature polycrystalline silicon and oxide thin‐film‐transistors

Abstract

We propose an in‐pixel temperature sensor using low‐temperature polycrystalline silicon and oxide (LTPO) thin‐film transistor (TFTs) for high‐luminance active matrix (AM) micro‐light‐emitting diode (LED) displays. By taking advantage of the different off‐current characteristics of p‐type LTPS TFTs and n‐type a‐IGZO TFTs under temperature change, we designed and fabricated a temperature sensor consists of only LTPO TFTs without additional sensing component or material. The fabricated sensor exhibits excellent temperature sensitivity of up to 71.8 mV/°C. In addition, a 64 × 64 temperature sensor array with 3T sensing pixel and integrated gate driver has also been fabricated, which demonstrates potential approach for maxing out the performance of high‐luminance AM micro‐LED display with real‐time in‐pixel temperature monitoring.

Contact Doping as a Design Strategy for Compact TFT-Based Temperature Sensing

“…In such cases, tuning of barrier properties would be a preferred route (e.g., pixels in highresolution sensing arrays). One possible application with strict areal requirements would be display and signage, as in-pixel temperature sensing is a desirable feature [28] and autonomous compensation exploiting NTD might be of value.…”

“…The principles outlined here translate to other contactcontrolled devices [15], as well as to different means of barrier engineering in diverse materials [17]- [19], [29], with applications in unsupervised temperature-dependent control, such as homeostasis. Here, the ability to produce an output current that decreases with temperature would lead to smart systems beyond display technology [28]. For example, smart therapeutic systems [30]- [32] integrated into wound dressings to maintain an optimum healing environment [33].…”

Gate driver with low‐temperature polycrystalline silicon and oxide thin‐film‐transistor circuits for low power consumption and narrow bezel AMOLED displays

“…LTPO TFTs have been fabricated with self‐aligned coplanar p‐type LTPS TFTs and dual gate (DG) back channel etch (BCE) a‐IGZO TFTs. Details of process were described in our previous reports 11,12 . Figure 1A shows the cross‐section view of LTPO TFT structure.…”

“…Details of process were described in our previous reports. 11,12 Figure 1A shows the cross-section view of LTPO TFT structure. Blue laser annealing (BLA) was performed to crystallize a-Si to take advantage of high mobility compared to ELA due to large grain size.…”

“…Recently, lowtemperature polycrystalline silicon and oxide (LTPO) TFTs are of increasing interest attention to take advantage of high current driving capability of LTPS TFTs and low off-state leakage current of oxide TFTs. [11][12][13][14][15][16][17] However, for applying LTPO technology to gate driver circuit, driving ability of the circuit under depletion mode of oxide TFTs should be considered.…”