AMOLED microdisplay device with active temperature control

摘要

An active-matrix organic light-emitting diode microdisplay device having a temperature control system including a temperature sensor and a control means for regulating the temperature of the OLED. The temperature is regulated by a bias transistor within the circuit, operating as a function of the temperature of the panel, such that low panel temperatures cause an increase in voltage of the bias transistor which draws a higher current through the top voltage drive transistor for self-heating the area surrounding the OLED.

主权项

1. An active-matrix organic light-emitting diode (AMOLED) display including:
a temperature sensor that is operative for providing a first signal that is based on a temperature of the AMOLED microdisplay; a voltage controlled oscillator that is operatively coupled with the temperature sensor, the voltage controlled oscillator operative for generating a control signal based on the first signal; and a plurality of pixels, each pixel including an organic light-emitting diode (OLED), wherein a first pixel of the plurality thereof includes a first pixel drive circuit comprising: a first drive transistor that is configured as a voltage follower, the first drive transistor receiving a first reference voltage and providing a first bias voltage to a first OLED of the plurality thereof, the first bias voltage being based on the first reference voltage; and a first bias transistor that is thermally coupled with the first OLED and that is dimensioned and arranged to:
(1) control a first current through the first drive transistor based on the control signal; and(2) dissipate power by sinking a second current that includes at least a portion of the first current; wherein the first bias transistor, first drive transistor, and first OLED are directly connected at first node that receives the first current from the first drive transistor and distributes the first current into the second current and a third current that is directed to the first OLED; wherein the temperature of the first OLED is based on the power dissipated by the first bias transistor.