Multi-Stage Pixel Circuit Control for Luminance Uniformity

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Self-luminous devices in display apparatuses suffer from non-uniform luminance and grayscale uniformity issues due to variations in current density, leading to display defects such as grayscale disorder and color shift.

Innovation Solution

A pixel circuit design that controls the light-emitting duration and driving current of self-luminous devices like LEDs through a combination of control circuits and transistors, adjusting the amplitude and frequency of driving signals to maintain efficient operation and uniform grayscale display.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the light-emitting duration and driving current are not controlled, then the self-luminous device can operate continuously, but non-uniform luminance and grayscale uniformity issues occur due to variations in current density

Engineering Contradiction:
Improvegrayscale uniformityVSAvoidcontrol circuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control circuit is divided into multiple functional modules: a first control circuit that generates first control signals based on input signals, and a second control circuit that generates second control signals based on the first control signals. This segmentation allows independent optimization of each control stage to achieve uniform luminance and grayscale display while managing overall system complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic control of the light-emitting device by adjusting both the amplitude and frequency of driving signals in real-time. The control circuits dynamically modify operating parameters based on feedback, enabling adaptive current density regulation that maintains uniform luminance and prevents grayscale defects during continuous operation

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If the amplitude and frequency of driving signals are adjusted to maintain efficient operation, then uniform grayscale display is achieved, but the control system becomes more complex

Engineering Contradiction:
Improveluminance consistencyVSAvoidsignal control complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The control system incorporates feedback mechanisms where the second control circuit receives first control signals and generates adjusted second control signals based on them. This feedback loop enables continuous monitoring and adjustment of driving parameters to maintain consistent luminance and grayscale uniformity, automatically compensating for variations in current density

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent systematically varies multiple parameters including amplitude and frequency of driving signals to optimize performance. By coordinating changes in these parameters through the multi-stage control circuits, the system achieves uniform grayscale display and prevents luminance non-uniformity while managing control complexity through parameter coordination rather than independent adjustment of each parameter

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4145434B1Pixel circuit and driving method therefor, display panel, and display device
Publication Date: 2025.10.08 BOE TECHNOLOGY GROUP CO LTD
  • EP4145434B1 patent drawingFigure 1
  • EP4145434B1 patent drawingFigure 2~3
  • EP4145434B1 patent drawingFigure 4

AI summary

A pixel circuit (101), comprising a driving circuit (30), a first control circuit (10), and a second control circuit (20). The driving circuit (30) writes a data signal of a data signal end (DATA) in response to a scan signal of a scan signal end (GATE), and generates a driving signal according to a first voltage of a first voltage end (V1) and the written data signal in response to a first enable signal of a first enable signal end (EM); the first control circuit (10) writes a first input signal of a first input signal end (S1) in response to a first control signal of a first control signal end (Q1), and transmits a third input signal of a third input signal end (S3) in response to the first input signal; or the first control circuit (10) writes a second input signal of a second input signal end (S2) in response to a second control signal of a second control signal end (Q2), and transmits a second enable signal of a second enable signal end (EM') in response to the second input signal; and the second control circuit (20) responds to and receives one of the third input signal and the second enable signal, transmits the driving signal to an element to be driven (L), and controls a working duration of said element (L).