Backlight Brightness Compensation for LCD RC Delay

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Solution Overview

Problem

Large LCD panels face brightness non-uniformity due to RC delay, which existing methods attempt to address by using two gate driver ICs, increasing costs and bezel size in multi-display systems.

Innovation Solution

A display apparatus and method that compensates for brightness non-uniformity by increasing backlight brightness away from the gate driver IC, using a synchronization signal and a lookup table to match pixel positions with appropriate brightness values, allowing the backlight driver to adjust brightness linearly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If two gate driver ICs are connected to both side surfaces of the display panel to compensate for RC delay, then brightness non-uniformity is reduced, but the bezel size increases and device complexity increases

Engineering Contradiction:
Improvebrightness uniformityVSAvoidbezel size
Core Design Contradiction:
Illumination intensityVSArea of stationary object

Solution Approach 1:

The patent changes the brightness parameter of the backlight unit dynamically along the gate line direction. By adjusting the backlight brightness to be higher at positions farther from the gate driver IC, the patent compensates for the RC delay effect without requiring additional driver ICs or larger bezels.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces the backlight unit as an intermediary element to compensate for RC delay effects. Instead of adding more gate driver ICs, the backlight brightness is modulated to counterbalance the voltage drop along the gate lines, serving as a mediator to achieve uniform display brightness.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If two gate driver ICs are connected to both side surfaces of the display panel to compensate for RC delay, then brightness non-uniformity is reduced, but the number of components increases

Engineering Contradiction:
Improvebrightness uniformityVSAvoidnumber of driver ICs
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent modifies the backlight driving parameters (brightness intensity) as a function of position along the gate line. This parameter change approach replaces the need for additional gate driver ICs, reducing device complexity while maintaining brightness uniformity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The backlight unit serves multiple functions: it provides illumination for the display and simultaneously acts as a compensation mechanism for RC delay effects. By making the backlight brightness position-dependent, a single backlight unit performs what would otherwise require multiple gate driver ICs.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Area of stationary object

If gate driver IC is mounted on only one side surface of the display panel, then bezel size is reduced and device complexity is reduced, but brightness non-uniformity increases due to RC delay

Engineering Contradiction:
Improvebezel sizeVSAvoidbrightness uniformity
Core Design Contradiction:
Area of stationary objectVSIllumination intensity

Solution Approach 1:

The patent applies position-dependent brightness modulation to the backlight unit, creating a brightness gradient that compensates for the RC delay effect. This allows single-sided gate driver IC mounting while maintaining uniform display brightness through parameter optimization.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3259751B1Display apparatus and method for controlling the same
Publication Date: 2021.05.19 SAMSUNG ELECTRONICS CO LTD
  • EP3259751B1 patent drawingFigure 1A
  • EP3259751B1 patent drawingFigure 1B
  • EP3259751B1 patent drawingFigure 2~3B

AI summary

A display apparatus includes a display panel including pixels arranged at an intersection of data lines and gate lines, a source driver IC configured to be disposed on one side surface of the display panel to apply a data voltage to the data lines, a gate driver IC configured to be disposed on any one of two side surfaces which are adjacent to the one side surface of the display panel to apply a gate driving voltage to the gate lines, and a controller configured to receive feedback on a gate driving voltage applied to at least one pixel, detect a distortion of the gate driving voltage applied to the pixel based on the feedback, adjust a level of the gate driving voltage applied to the gate lines to compensate for the distortion of the gate driving voltage, and apply the adjusted gate driving voltage to the gate lines.