Pixel Circuit Grayscale Control for Micro LED
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Solution Overview
Problem
Traditional current control driving circuits are inadequate for achieving grayscale display requirements of Micro LED and Mini LED due to their high brightness and high reliability, as they fail to maintain consistent light emitting efficiency and color coordinates under varying current densities.
Innovation Solution
A pixel circuit design incorporating a light emitting element, driving circuit, reset circuits, and data writing-in circuits, along with control terminals and control signals, to manage current flow and initial voltage settings, ensuring precise grayscale control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional current control driving circuits are used, then the circuit structure is simple, but the light emitting efficiency and color coordinates cannot be maintained consistent under varying current densities
Solution Approach 1:
The pixel circuit is divided into multiple functional modules: a driving circuit for current control, a reset circuit for voltage initialization, and a data writing-in circuit for sequential voltage input. This segmentation allows each module to perform its specific function optimally, ensuring consistent light emitting efficiency while managing complexity through modular design
Solution Approach 2:
The reset circuit performs preliminary action by initializing the voltage of the light emitting element to a first initial voltage before data writing. This preliminary voltage setting ensures that the light emitting element starts from a known state, enabling consistent light emitting characteristics during subsequent operation and resolving the reliability issue
2Illumination intensity
If high current density is applied to achieve grayscale display, then the brightness requirement is met, but the light emitting efficiency and color coordinates change
Solution Approach 1:
The invention changes the voltage parameter of the light emitting element through the reset circuit, which initializes the voltage to a first initial voltage before data writing. This parameter control ensures that even at high current densities required for brightness, the light emitting efficiency and color coordinates remain consistent by maintaining proper voltage conditions
3Manufacturing precision
If sequential voltage writing is implemented, then the grayscale control precision is improved, but the writing time increases
Solution Approach 1:
The data writing-in circuit implements periodic action by sequentially providing different voltages to the light emitting element at different time periods: first initial voltage during a first time period, first display data voltage during a second time period, and second display data voltage during a third time period. This periodic sequential writing achieves precise grayscale control while managing the writing time through structured timing
Data Source
AI summary
A pixel circuit, a driving method and a display device are provided. The pixel circuit includes a driving circuit, a first reset circuit and a data writing-in circuit; the data writing-in circuit sequentially provides a display data voltage and a light emitting time control data voltage to the writing-in node under the control of a writing-in control signal; the first reset circuit writes a first initial voltage into the first electrode of the light emitting element under the control of a first reset control signal during a reset time period set between a time period for writing the display data voltage and a time period for writing the light emitting time control data voltage.