Micro LED Pixel Circuit with Dual Current and Time Control

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Solution Overview

Problem

Micro LED display technologies face challenges in achieving high contrast and efficient light emission across full grayscale, due to limitations in controlling current density and light-emitting efficiency.

Innovation Solution

A pixel circuit comprising a current control circuit, a time control circuit, and a light-emitting component, where the intensity and passage time of the driving current are controlled to adjust grayscale, improving contrast and light-emitting efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If traditional current control methods are used in Micro LED display, then the circuit structure is simple, but the contrast ratio and light-emitting efficiency cannot be improved across full grayscale

Engineering Contradiction:
Improvecontrast ratioVSAvoidcircuit structure
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The pixel circuit is segmented into two independent control paths: a current control circuit (CCC) that controls driving current intensity, and a time control circuit (TCC) that controls light emission duration. This segmentation allows independent optimization of brightness and timing, enabling high contrast ratio across full grayscale while maintaining manageable circuit complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention adds a time dimension to the traditional current-only control method. By controlling both the intensity (current magnitude) and duration (passage time) of the driving current, the system creates a two-dimensional control space that significantly expands the grayscale range and contrast capability beyond what single-parameter control can achieve

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Illumination intensity

If higher current density is applied to Micro LED, then brightness increases, but light-emitting efficiency decreases

Engineering Contradiction:
ImprovebrightnessVSAvoidlight-emitting efficiency
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The time control circuit implements periodic on/off control of the driving current through pulse width modulation. By delivering current in controlled pulses rather than continuous flow, the system allows the Micro LED to operate at high current density during active periods (achieving high brightness) while reducing average power consumption and heat generation (maintaining light-emitting efficiency) through off periods

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts both the magnitude and duration of driving current based on required brightness levels. Rather than using static high current for all grayscale levels, the circuit dynamically modulates current parameters to keep the Micro LED operating in its high-efficiency region while achieving the desired brightness output

Inventive Principle:
Principle #15Dynamics

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 enhances display contrast and reduces color coordinate shifts by allowing the Micro LED to operate at higher light-emitting efficiency regions across full grayscale.

Implementation Method 1

a light-emitting component (300), which are configured to emit a light in response to the driving current

Methodology Applied
Scientific EffectLight emission: Light Emitting Diode

Data Source

PatentEP3818516B1Pixel circuit, driving method thereof, and display panel
Publication Date: 2025.04.23 BOE TECHNOLOGY GROUP CO LTD
  • EP3818516B1 patent drawingFigure 1
  • EP3818516B1 patent drawingFigure 2
  • EP3818516B1 patent drawingFigure 3

AI summary

A pixel circuit (10), its driving method, and a display panel (2000) having the pixel circuit (10) are provided. The pixel circuit (10) includes a current control circuit (100), a time control circuit (200), and a light-emitting component (300), which are electrically coupled to one another in series along a common passage path of a driving current. The current control circuit (100) is configured to control an intensity of the driving current according to a display data signal (Vdata1) received thereby. The time control circuit (200) is configured to control a passage time of the driving current according to a time data signal (Vdata2) and a switch control signal (Em1) received thereby. The light-emitting component (300) is configured to emit a light according to the intensity and the passage time of the driving current.