Pixel Circuit with Dual LEDs for Emission Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In display devices using light emitting diodes (LEDs), the emission efficiency is compromised due to parasitic capacitance and uneven voltage application, leading to some LEDs not emitting light when both electrodes are biased with the same voltage.
Innovation Solution
A pixel design that includes transistors to manage driving currents and voltage application, with specific power supply lines and transistors configured to ensure that both LEDs emit light by initializing parasitic capacitance and applying voltages effectively, allowing for sequential or concurrent light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If both electrodes are biased with the same voltage, then the manufacturing process is simplified, but emission efficiency deteriorates because no current flows to some LEDs
Solution Approach 1:
The pixel electrode is divided into multiple sub-electrodes (first electrode and second electrode) with different voltage levels. This segmentation allows different regions of the electrode to drive different LEDs independently, ensuring that current flows to all LEDs even when power consumption is reduced. The segmentation resolves the contradiction by maintaining simple voltage application (only two voltage levels needed) while improving emission efficiency through differentiated voltage biasing across sub-electrodes.
2Device complexity
If parasitic capacitance is not initialized, then the circuit structure is simpler, but LED emission is compromised due to voltage imbalance
Solution Approach 1:
A capacitor is introduced to initialize and maintain the voltage difference between the first and second electrodes during non-emission periods. This preliminary action of voltage initialization ensures that when emission occurs, the electrodes are already in the correct voltage state to drive current through the LEDs. The capacitor performs the preliminary action of maintaining voltage differential, resolving the contradiction between circuit simplicity and emission reliability.
3Loss of energy
If voltage is continuously applied to maintain LED emission, then emission efficiency is improved, but power consumption increases
Solution Approach 1:
The system employs periodic voltage application where the first electrode receives a higher voltage during emission periods and a lower voltage during non-emission periods, while the second electrode maintains a constant intermediate voltage. This periodic action ensures that LEDs receive sufficient current during emission (improving emission efficiency) while reducing overall power consumption during non-emission periods. The timing controller coordinates this periodic voltage switching to match the display refresh cycle.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves the emission efficiency of LEDs by ensuring all LEDs emit light, enhancing display performance and accuracy in gray-scale representation.
Implementation Method 1
a light emitting diode (LED) emits light corresponding to electrical signals applied to respective electrodes
Implementation Method 2
configured to emit light by the driving current
Data Source
AI summary
A pixel includes: a first transistor configured generate a driving current corresponding to a data signal transmitted from a corresponding data line; a first light emitting diode (LED) including a cathode connected to a first power supply line and an anode connected to a second power supply line, and configured to emit light by the driving current; a second light emitting diode (LED) including a cathode connected to the second power supply line and an anode connected to the first power supply line, and configured to emit light by the driving current; a second transistor connected to the anode of the first light emitting diode (LED), and configured to transmit the driving current to the first light emitting diode (LED); and a third transistor connected to the anode of the second light emitting diode (LED), and configured to transmit the driving current to the second light emitting diode (LED.