Dual-LED Pixel Circuit With Current Splitting for Stable Low Brightness
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Solution Overview
Problem
Existing pixel circuits using micro LEDs face challenges in maintaining luminous efficiency and stability at both high and low display brightness levels, particularly at low current densities.
Innovation Solution
A pixel circuit design incorporating a first driver and a second driver in parallel, with a current splitting path, allows for adjusting brightness by varying the current density through the second driver, enabling the first and second light-emitting elements to emit light independently or together based on display data, thereby maintaining luminous efficiency and stability across different brightness levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single light-emitting element is used in the pixel circuit, then the device complexity is reduced, but the luminous efficiency and stability cannot be maintained at both high and low display brightness levels
Solution Approach 1:
The pixel circuit is divided into two separate light-emitting elements (first light-emitting element and second light-emitting element) with independent driving paths. The first driver controls the first light-emitting element for high brightness output, while the second driver controls the second light-emitting element for low brightness output. This segmentation allows each element to operate in its optimal brightness range, maintaining luminous efficiency and stability across the full brightness spectrum without requiring a complex single-element solution.
2Illumination intensity
If the current density is reduced to achieve low display brightness, then the display can show dimmer images, but the luminous stability of micro LEDs deteriorates at low current densities
Solution Approach 1:
The driving function is segmented into two independent drivers: the first driver maintains sufficient current density for stable operation of the first light-emitting element at high brightness, while the second driver independently controls the second light-emitting element at low brightness levels. This segmentation eliminates the problem of luminous instability that occurs when a single element operates at low current density, as each element has its own optimized driving path.
3Illumination intensity
If the brightness of the first light-emitting element is reduced to achieve low display brightness, then the display can show dimmer images, but the operating efficiency of the pixel circuit deteriorates
Solution Approach 1:
The pixel circuit is segmented into two parallel light-emitting paths, each with its own driver. The first driver and first light-emitting element handle high brightness requirements with high operating efficiency, while the second driver and second light-emitting element handle low brightness requirements. This segmentation allows the circuit to maintain high operating efficiency across the full brightness range by selecting the appropriate path, rather than forcing a single element to operate inefficiently at low brightness.
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
The solution effectively maintains luminous efficiency and improves stability of micro LEDs by adjusting current density and brightness, ensuring high operating efficiency in both high and low brightness regions.
Implementation Method 1
The first light-emitting element receives the driving current and emits light according to the driving current. The second light-emitting element receives the driving current and the splitting current, and emits light according to the driving current and the splitting current.
Data Source
AI summary
Disclosed are a pixel circuit and a display brightness adjusting method thereof. The pixel circuit includes a first driver, a first light-emitting element, a second driver, and a second light-emitting element. The first driver is used to provide a driving current according to a display data. The first light-emitting element receives the driving current and emits light according to the driving current. The second driver forms a current splitting path and provides a splitting current according to the display data. The second light-emitting element receives the driving current and the splitting current, and emits light according to the driving current and the splitting current.