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US 12,738,195 B2Granted
Micro LED driving circuit comprising double gate transistor and micro LED display device comprising thereof
AssigneeSeoul National University R&Db Foundation
InventorsSoo Yeon Lee, Ji Min Kang
Life of this patent
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Abstract
The present invention relates to a micro LED driving circuit including a double gate transistor, and includes a PWM circuitry for controlling the emission time of the micro LED; and a CCG circuitry that controls a constant current to be supplied while the micro LED emits light based on the PWM data voltage.
Claims9
A micro LED driving circuit comprising a double gate transistor, comprising
- a PWM circuitry adjusting light emitting time of a micro LED, the PWM circuitry comprising a PWM circuitry driving transistor having a double gate structure,
- wherein the double gate transistor compensates for threshold voltage shift of the driving TFT while determining an on/off timing through comparison of a PWM data voltage and a sweep voltage (Vsweep);
- wherein the PWM circuitry further comprises a capacitor (C3) and a switching transistor T9), and wherein, in a second step, the PWM data voltage is applied through the switching transistor (T9) and a voltage stored in the capacitor (C3) is Vref_PWM−Vth_T5−Vdata_PWM;
- and
- a CCG circuitry controlling a constant current to be supplied during light emission of the micro LED based on the PWM data voltage,
- wherein the CCG circuitry further comprises at least two capacitors arranged to provide capacitive coupling, the at least two capacitors comprising a first capacitor (C1) and a second capacitor (C2), and wherein a driving voltage (VDD) is connected only to the CCG circuitry without a line connected to the PWM circuitry, and wherein, in a light emission step, when the PWM circuitry driving transistor is turned on by the comparison of the PWM data voltage and the sweep voltage (Vsweep), the first capacitor (C1) comprised in the CCG circuitry is discharged so that light emission of the micro LED is stopped.
3 more elements
A display device comprising a driving circuit of a micro LED, comprising
- a display panel comprising a pixel array in which pixels composed of a plurality of inorganic light emitting elements are arranged in a plurality of row lines, and subpixel circuits which are prepared for each of the plurality of inorganic light emitting elements, and provide a driving current to the inorganic light emitting elements;
- and
- a driver which sets an image data voltage to the subpixel circuits of the display panel in row line order, during a data setting period, and drives the subpixel circuits so that the driving current is provided to the inorganic light emitting elements of the pixel array in row line order, based on a sweep signal (Vsweep) which sweeps from a first voltage to a second voltage and a set image data voltage, during a light emission period,
- wherein the subpixel circuits, comprise
- a PWM circuitry controlling light emitting time of a micro LED;
- and
- a CCG circuitry controlling a constant current to flow during light emission of the micro LED,
- wherein the PWM circuitry comprises a PWM circuitry driving transistor having a double gate structure, a capacitor (C3), and a switching transistor (T9) through which a PWM data voltage is applied to the capacitor (C3), and wherein the CCG circuitry comprises a first capacitor (C1) and a second capacitor (C2) providing capacitive coupling, such that, when Vsweep exceeds Vref_PWM−Vdata_PWM, the double gate transistor is turned on and the first capacitor (C1) is discharged to stop light emission of the micro LED.
5 more elements
Dependencies are inferred from the claim text.