| Summary: | 碩士 === 國立交通大學 === 光電工程研究所 === 104 === In this paper, we present a [novel sentinel voltage control method] of
external compensating driving circuit which could mainly be applied to the
active-matrix organic light-emitting diode displays (AMOLED). The pixel driving
current is gradually increased by the ramp voltage at gate and converted to voltage in
real time. When the sensed voltage is equal to the sentinel voltage, the gate voltage
stops changing. Thus, the gate voltage is pinched at the value corresponding to the
target driving current. The pixel contains only three thin-film transistors (TFTs) and
one capacitor, which is suitable for high PPI display. Owing to the small area of the
high PPI pixel, the operation current of driving TFT may drop down to an extremely
low level. However, this compensation circuit can work for low current level, even
when the TFT is operated in the subthreshold where the current exponentially varies
III
with its gate voltage.
Although the compensation circuit can be successfully operated, there are still
some issue needs to solve when it works. Hence, we proposed an advanced version of
this external compensation circuit in the following chapter. Regarding to different
issue, we present multiply approaches to overcome them and make the circuit design
complete.
Thus, using these compensation circuit can conquer the operation difficulty of high
PPI AMOLED and make external driver IC work simple by pinching off signal at
expected value. Along with display panels in mobile devices, wearable devices,
Augmented Reality (AR) products and Virtual Reality (VR) products being
indispensable tools in recent years, these techniques are sure to be widely used.
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