Pixel Driving Circuit With Dynamic Emission Timing for Mini/Micro LEDs
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Solution Overview
Problem
Existing pixel driving circuits for mini LED and micro LED display apparatuses face challenges in achieving high pixel density and uniform brightness, particularly at low gray scales due to limitations in transistor size and stability, leading to poor brightness uniformity.
Innovation Solution
A pixel driving circuit with a driving sub-circuit and control sub-circuit that includes transistors and capacitors, allowing for precise control of current paths and enable signals to manage luminance and brightness uniformity by adjusting current density and emission times, using Mini LEDs or Micro LEDs as light-emitting elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transistor size is reduced to achieve higher pixel density, then pixel density is improved, but brightness uniformity deteriorates
Solution Approach 1:
The patent introduces an enable signal control terminal that dynamically adjusts the emission time of the light-emitting element based on gray scale levels. For low gray scales, the emission time is shortened to prevent excessive current density from causing brightness non-uniformity in mini/micro LEDs. This dynamic control allows the use of smaller transistors for high pixel density while maintaining brightness uniformity through adaptive emission time adjustment.
2Illumination intensity
If current density is increased to improve luminance, then luminance is improved, but brightness uniformity deteriorates at low gray scales
Solution Approach 1:
The patent uses periodic pulse-width modulation (PWM) through the enable signal to control the emission time of the light-emitting element. By adjusting the duty cycle of the enable signal, the patent achieves different gray scales while maintaining appropriate current density. For low gray scales, the emission time is reduced, which prevents excessive current density and maintains brightness uniformity while still achieving the desired luminance level.
Data Source
AI summary
A pixel driving circuit includes a driving sub-circuit and a control sub-circuit. The driving sub-circuit is coupled to a data signal terminal, a scan signal terminal, a first power supply voltage terminal, an enable signal control terminal and an element to be driven, and the driving sub-circuit is configured to, in response to an enable signal, transmit a generated driving signal to the element to be driven, and control a current path transmitting the driving signal to be turned on and off. The control sub-circuit is coupled to the enable signal control terminal, and the control sub-circuit is configured to, in response to a signal received at the control signal terminal, transmit a signal received at a first enable signal terminal or a signal received at a second enable signal terminal to the enable signal control terminal.