Multiplexer Timing for Uniform Luminance in OLED Displays

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Solution Overview

Problem

The degradation of image quality in organic light-emitting display devices due to the driving characteristics of the organic light-emitting elements is a significant issue that needs to be addressed.

Innovation Solution

The implementation of a display device with a multiplexer (MUX) that controls the turn-on periods of data lines to prevent overlap and ensure synchronized charging of pixels, thereby maintaining consistent luminance across the display panel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple data lines are driven simultaneously with overlapping control signals, then the charging speed of pixels is improved, but image quality degrades due to luminance inconsistency

Engineering Contradiction:
Improvecharging speedVSAvoidluminance consistency
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies periodic action by dividing the frame period into multiple sub-periods, where each data line is driven in a specific time slot. The control signals are generated periodically with non-overlapping enabling periods, ensuring that each pixel is charged in sequence rather than simultaneously. This temporal segmentation maintains luminance consistency while still achieving complete charging within the frame period.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent segments the simultaneous charging process into multiple sequential stages. Instead of driving all data lines at once, the system divides the charging operation into discrete time slots, with each data line receiving its dedicated charging period. This segmentation prevents signal overlap and ensures uniform luminance across all pixels.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If the turn-on period of data lines is extended to ensure complete charging, then luminance consistency is improved, but the response time of the display increases

Engineering Contradiction:
Improveluminance consistencyVSAvoidresponse time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent uses periodic action to structure the charging process into efficient time slots within each frame period. By organizing data line driving in sequential periods with optimized durations, the system achieves complete pixel charging without extending the overall response time. Each data line receives sufficient charging time in its designated slot, maintaining luminance consistency while adhering to the frame rate requirements.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements preliminary action by pre-planning the charging sequence of data lines within the frame period. The control signals are generated in advance with predetermined enabling periods that ensure each pixel is fully charged before the next data line is activated. This proactive timing arrangement prevents charging deficiencies without requiring extended response times.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If multiplexers are used to control multiple data lines, then device complexity is reduced, but image quality degrades due to driving characteristics of organic light-emitting elements

Engineering Contradiction:
Improvenumber of control signalsVSAvoidimage quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies periodic action to the multiplexer control by generating enable signals that activate different data lines in sequential periods. The multiplexer switches between data lines according to a periodic pattern, ensuring that each line receives appropriate charging time. This periodic switching mechanism maintains image quality while utilizing the complexity-reducing benefits of multiplexer architecture.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent segments the control signal generation into distinct time slots for each data line. The multiplexer is controlled to switch between different data lines in sequence, with each switching event occurring in a dedicated period. This segmentation allows the system to manage multiple data lines with fewer control circuits while maintaining precise timing for optimal image quality.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4024382B1Display device including multiplexer
Publication Date: 2026.01.28 LG DISPLAY CO LTD
  • EP4024382B1 patent drawingFigure 1
  • EP4024382B1 patent drawingFigure 2
  • EP4024382B1 patent drawingFigure 3~4

AI summary

Proposed is a display device (1) including a display panel (50) including multiple pixels (PX) each of which includes multiple sub-pixels (SPX), and the display device includes multiple data lines (DL1, ..., DLm) respectively connected to the multiple sub-pixels (SPX), multiple gate lines (GL1, ..., GLn) respectively connected to the multiple pixels (PX), and N multiplexers (MUX) (N is a natural number larger than 1) (MUX1, MUX2, MUX3) disposed at each input terminal of the multiple data lines (DL1, ..., DLm), wherein, in one H period (1H), a length of a turn-on period ((2)) of a first MUX (MUX1) may be different from that of a turn-on period ((4)) of an Nth MUX (MUX3), wherein the one H period (1H) is a period in which a scan signal (Scan) is supplied through one gate line.