Micro-LED Pixel Circuit Current Density Control
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Solution Overview
Problem
Micro-LED display devices face challenges in achieving high contrast and efficient power usage due to limitations in current density, leading to display defects and reduced performance.
Innovation Solution
A pixel circuit with a specific configuration including resetting, data writing, charging and discharging, output control, and switch sub-circuits, along with a driving current supply circuit, is used to control voltage and current to the Micro-LED, allowing for precise adjustment of current density and operation time to optimize display performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If current density is increased to improve display brightness, then illumination intensity is improved, but color cast and efficiency reduction occur
Solution Approach 1:
The patent implements dynamic control of the Micro-LED operating state by using a charging and discharging sub-circuit to adjust the current density in real-time. The circuit transitions the Micro-LED between different operating states (charging state for brightness, discharging state for color stability), allowing the system to maintain high brightness while avoiding color cast by dynamically adjusting operational parameters rather than maintaining a fixed high current density
Solution Approach 2:
The patent employs periodic charging and discharging cycles of the Micro-LED through the charging and discharging sub-circuit. During charging phases, the Micro-LED operates at higher current density for brightness; during discharging phases, it operates at lower current density to maintain color stability. This periodic alternation allows the display to achieve high average brightness while preventing continuous high current density from causing color cast
2Illumination intensity
If current density is increased to improve display brightness, then illumination intensity is improved, but power consumption increases
Solution Approach 1:
The patent uses periodic charging and discharging cycles to control Micro-LED operation. During charging phases, the Micro-LED consumes more power for higher brightness; during discharging phases, power consumption is reduced. This periodic action pattern allows the display to achieve high average brightness while reducing overall power consumption compared to continuous high-current operation
Solution Approach 2:
The charging and discharging sub-circuit recovers energy by capturing and storing electrical energy in capacitive elements during charging phases, then releasing this stored energy during discharging phases to maintain Micro-LED operation. This energy recovery mechanism reduces overall power consumption while maintaining display brightness by reusing energy that would otherwise be lost
3Illumination intensity
If current density is increased to improve display performance, then illumination intensity is improved, but display defects increase
Solution Approach 1:
The patent implements dynamic state transitions of the Micro-LED through the charging and discharging sub-circuit, switching between charging state (for brightness enhancement) and discharging state (for defect prevention). This dynamic operation allows the system to achieve high display performance while maintaining reliability by avoiding sustained high current density that causes display defects
Solution Approach 2:
The circuit design incorporates protective mechanisms that preemptively prevent display defects by controlling the maximum current density and duration. The charging and discharging cycles are designed with built-in limits that prevent the Micro-LED from operating in conditions that would cause defects, providing beforehand cushioning against reliability issues
Data Source
AI summary
The present disclosure provides a pixel circuit including: a first resetting sub-circuit for writing a reference voltage and an initialization voltage to a first node and a second node, respectively; a first data writing sub-circuit for writing a first data voltage to a second node; a first output control sub-circuit for supplying a voltage at the first node to the switch sub-circuit; a charging and discharging sub-circuit for performing charge processing or discharge processing on the first node in response to control of the first data voltage; a switch sub-circuit coupled to the signal supply terminal and an element to be driven for controlling electrical coupling and decoupling between the signal supply terminal and the element to be driven under control of the voltage at the first node. The present disclosure also provides a driving method of the pixel circuit and a display device.