Pixel Driving Circuit With Time-Controlled Compensation for Uniform Brightness
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Solution Overview
Problem
Micro light-emitting devices in pixel driving circuits exhibit inconsistent turn-on voltages and photoelectric conversion characteristics due to manufacturing variations, leading to uneven luminous efficiency and high power consumption, affecting display quality.
Innovation Solution
A pixel driving circuit with a driving control sub-circuit and time control sub-circuit, including capacitors and transistors, to regulate current and duration, ensuring consistent luminous efficiency and reduced power consumption by controlling the driving signal magnitude and duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If micro light-emitting devices are used in pixel driving circuits, then the device size is reduced and glass-based backplane is enabled, but manufacturing uniformity causes inconsistent turn-on voltages and photoelectric conversion characteristics
Solution Approach 1:
The patent employs dual data signal writing mechanisms: one controls the driving current magnitude through a driving transistor, while another controls the operating duration through a time control transistor. This parameter separation allows independent optimization of current level and time duration to compensate for device variations.
Solution Approach 2:
The circuit dynamically adjusts the operating duration of the light-emitting device based on the second data signal. By controlling the turn-off timing of the time control transistor, the circuit adapts the current flow duration to achieve consistent luminous output despite variations in device characteristics.
2Duration of action of moving object
If current density is reduced to extend operating duration, then luminous duration increases, but luminous efficiency decreases and power consumption increases
Solution Approach 1:
The circuit dynamically controls the operating duration through a time control transistor that responds to a second data signal. This allows the current to flow for precisely the required duration without extending it unnecessarily, thereby avoiding the energy waste that would result from prolonged low-current operation.
Solution Approach 2:
The patent implements periodic control cycles where the driving transistor is activated only during the specific time window determined by the time control transistor. This periodic activation ensures the light-emitting device operates at high current density only when needed, maintaining efficiency while achieving the required luminous duration.
3Manufacturing precision
If manufacturing process uniformity is improved, then turn-on voltage consistency increases, but manufacturing complexity and cost increase
Solution Approach 1:
The circuit performs self-compensation by using the actual device characteristics (turn-on voltage, photoelectric conversion efficiency) to dynamically adjust operating parameters. The dual data signal mechanism automatically adapts to each device's specific characteristics, eliminating the need for external calibration or complex manufacturing control.
Solution Approach 2:
Instead of attempting to manufacture all devices with identical characteristics, the patent changes the operational parameters (current magnitude and time duration) based on each device's actual properties. This approach accepts manufacturing variations and compensates through electrical parameter adjustment rather than mechanical precision.
4Use of energy by moving object
If driving current magnitude is increased to improve luminous efficiency, then luminous efficiency increases, but the operating duration must be reduced which affects display brightness control
Solution Approach 1:
The circuit dynamically balances current magnitude and time duration through two independent control pathways. The driving transistor controls current magnitude for efficiency, while the time control transistor adjusts operating duration for brightness control, allowing the system to maintain high efficiency across different gray levels.
Solution Approach 2:
The patent uses periodic control cycles where high-current pulses are delivered for precisely controlled durations. By adjusting the pulse width (operating duration) while maintaining high current density, the circuit achieves both high luminous efficiency and variable brightness levels through pulse width modulation.
Data Source
AI summary
A pixel driving circuit includes a driving control sub-circuit and a time control sub-circuit. The driving control sub-circuit includes a first driving sub-circuit. The first driving sub-circuit is configured to output a driving signal to drive an element to be driven to operate. The time control sub-circuit includes a second driving sub-circuit. The second driving sub-circuit is configured to output a third voltage signal to make the first driving sub-circuit stop outputting the driving signal, so as to control operating duration of the element to be driven.