Display Driver Voltage Drop Correction Circuit

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Solution Overview

Problem

Flat-panel displays, particularly AMOLEDs, suffer from luminance uniformity issues due to voltage drops in the electroluminescence voltage supply, leading to color shifts and decreased luminosity across the display panel, especially as panel size increases.

Innovation Solution

Incorporating a correction circuit within the display driver integrated circuit to sense and calculate voltage drops, allowing for the adjustment of pixel data voltage to match the electroluminescence voltage drop, either by mirroring the drop or predistorting the electroluminescence voltage to maintain consistent brightness and color across the panel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the display panel size is increased, then the display area is improved, but voltage drop increases causing luminance non-uniformity

Engineering Contradiction:

Improvedisplay areaVSAvoidluminance uniformity

Core Design Contradiction:

Area of stationary objectVSIllumination intensity

Solution Approach 1:

The correction circuit pre-calculates and applies compensation values to counteract the voltage drop before it affects the display output. By sensing the electroluminescence voltage and calculating the voltage drop in advance, the system adjusts the pixel data voltage proactively to maintain uniform luminance across the enlarged display panel.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where the correction circuit continuously senses the electroluminescence voltage supplied to the display panel, calculates the actual voltage drop, and adjusts the pixel data voltage accordingly. This closed-loop control ensures that luminance uniformity is maintained despite the increased panel size causing greater voltage drops.

Inventive Principle:

Principle #23Feedback

2Illumination intensity

If the electroluminescence voltage supply is increased to compensate for voltage drop, then luminance uniformity is improved, but power consumption increases

Engineering Contradiction:

Improveluminance uniformityVSAvoidpower consumption

Core Design Contradiction:

Illumination intensityVSUse of energy by moving object

Solution Approach 1:

Instead of uniformly increasing the electroluminescence voltage across the entire panel, the correction circuit dynamically adjusts the pixel data voltage based on the sensed voltage drop at different locations. This selective parameter adjustment compensates for luminance non-uniformity while minimizing overall power consumption by only applying corrections where needed.

Inventive Principle:

Principle #35Parameter changes

3Illumination intensity

If a correction circuit is added to sense and calculate voltage drops, then luminance uniformity is improved, but device complexity increases

Engineering Contradiction:

Improveluminance uniformityVSAvoidcircuit complexity

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The correction circuit functionality is integrated into the existing display driver architecture, merging the voltage sensing, calculation, and compensation functions with the pixel data voltage supply. This consolidation achieves luminance uniformity correction while minimizing the increase in device complexity by utilizing existing circuit resources.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS10796629B2Display panel voltage drop correction

Publication Date: 2020.10.06 APPLE INC

AI summary

A flat-panel display device and method to compensate for a voltage drop by supply voltage in the flat-panel display.